Chemistry Redspot Olevel

Syllabus
Cambridge IGCSE®
Chemistry 0620
For examination in June and November 2020 and 2021.
Also available for examination in March 2020 and 2021 for India only.
Version 1
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Contents
1 Why choose this syllabus? ..................................................................................................... 2
2 Syllabus overview .................................................................................................................... 5

Aims 5
Content overview 6
Assessment overview 7
Assessment objectives 8
3 Subject content .......................................................................................................................10
4 Details of the assessment ................................................................................................... 28

Core Assessment 28
Extended Assessment 28
Practical Assessment 29
Glossary of terms used in science papers 33
5 Appendix................................................................................................................................... 34
The Periodic Table 34
Safety in the laboratory 35
Mathematical requirements 35
Presentation of data 36
ICT opportunities 37
Conventions (e.g. signs, symbols, terminology and nomenclature) 37
6 What else you need to know .............................................................................................. 38

Before you start 38
Making entries 39
After the exam 40
How students and teachers can use the grades 40
Grade descriptions 40
Changes to this syllabus for 2020 and 2021 41
Changes to this syllabus

For information about changes to this syllabus for 2020 and 2021, go to page 41.
The latest syllabus is version 1, published September 2017. There are no significant changes which affect
teaching.
Any textbooks endorsed to support the syllabus for examination from 2016 are still suitable for use with this
syllabus.
Cambridge IGCSE Chemistry 0620 syllabus for 2020 and 2021.
1 Why choose this syllabus?
Key benefits
Cambridge IGCSE® syllabuses are created especially for international students. For over 25 years, we have worked
with schools and teachers worldwide to develop syllabuses that are suitable for different countries, different types
of schools and for learners with a wide range of abilities.
Cambridge IGCSE Chemistry enables learners to:

•• increase their understanding of the technological world
•• take an informed interest in scientific matters
•• recognise the usefulness (and limitations) of scientific method, and how to apply this to other disciplines and in
everyday life
•• develop relevant attitudes, such as a concern for accuracy and precision, objectivity, integrity, enquiry, initiative
and inventiveness
•• develop an interest in, and care for, the environment
•• better understand the influence and limitations placed on scientific study by society, economy, technology,
ethics, the community and the environment
•• develop an understanding of the scientific skills essential for both further study and everyday life.
Our programmes balance a thorough knowledge and understanding of a subject and help to develop the skills
learners need for their next steps in education or employment.
Our approach encourages learners to be:
Cambridge
learner
‘The strength of Cambridge IGCSE qualifications is internationally recognised and has provided
an international pathway for our students to continue their studies around the world.’
Gary Tan, Head of Schools and CEO, Raffles International Group of Schools, Indonesia
2 www.cambridgeinternational.org/igcse Back to contents page

Cambridge IGCSE Chemistry 0620 syllabus for 2020 and 2021. Why choose this syllabus?
Recognition and progression

The combination of knowledge and skills in Cambridge IGCSE Chemistry gives learners a solid foundation for
further study. Candidates who achieve grades A* to C are well prepared to follow a wide range of courses including
Cambridge International AS & A Level Chemistry.
Cambridge IGCSEs are accepted and valued by leading universities and employers around the world as evidence of
academic achievement. Many universities require a combination of Cambridge International AS & A Levels and
Cambridge IGCSEs or equivalent to meet their entry requirements.
UK NARIC, the national agency in the UK for the recognition and comparison of international qualifications and
skills, has carried out an independent benchmarking study of Cambridge IGCSE and found it to be comparable to
the standard of GCSE in the UK. This means students can be confident that their Cambridge IGCSE qualifications
are accepted as equivalent to UK GCSEs by leading universities worldwide.
Learn more at www.cambridgeinternational.org/recognition
‘Cambridge IGCSE is one of the most sought-after and recognised qualifications in the world. It
is very popular in Egypt because it provides the perfect preparation for success at advanced level
programmes.’
Mrs Omnia Kassabgy, Managing Director of British School in Egypt BSE
Back to contents page www.cambridgeinternational.org/igcse 3

Cambridge IGCSE Chemistry 0620 syllabus for 2020 and 2021. Why choose this syllabus?
Supporting teachers
We provide a wide range of practical resources, detailed guidance, and innovative training and professional
development so that you can give your learners the best possible preparation for Cambridge IGCSE.
Teaching resources Exam preparation resources

• School Support Hub • Question papers
www.cambridgeinternational.org/support • Mark schemes
• Syllabus • Example candidate responses to understand
• Scheme of work what examiners are looking for at key grades
• Learner guide • Examiner reports to improve future teaching
• Discussion forum
• Resource list
• Endorsed textbooks and digital resources Support for
Cambridge
Training IGCSE Community
• Face-to-face workshops around the world You can find useful information, as well as
• Online self-study training share your ideas and experiences with other
teachers, on our social media channels and
• Online tutor-led training
community forums.
• Cambridge Professional Development
Find out more at
Qualifications
www.cambridgeinternational.org/social-media

2 Syllabus overview
Aims
The aims describe the purposes of a course based on this syllabus.
You can deliver some of the aims using suitable local, international or historical examples and applications, or
through collaborative experimental work.
The aims are to:

•• p
rovide an enjoyable and worthwhile educational experience for all learners, whether or not they go on to
study science beyond this level
•• enable learners to acquire sufficient knowledge and understanding to:
–– become confident citizens in a technological world and develop an informed interest in scientific matters
–– be suitably prepared for studies beyond Cambridge IGCSE
•• a llow learners to recognise that science is evidence based and understand the usefulness, and the limitations, of
scientific method
•• develop skills that:
–– are relevant to the study and practice of chemistry
–– are useful in everyday life
–– encourage a systematic approach to problem solving
–– encourage efficient and safe practice
–– encourage effective communication through the language of science
•• develop attitudes relevant to chemistry such as:
–– concern for accuracy and precision
–– objectivity
–– integrity
–– enquiry
–– initiative
–– inventiveness
•• enable learners to appreciate that:
–– science is subject to social, economic, technological, ethical and cultural influences and limitations
–– the applications of science may be both beneficial and detrimental to the individual, the community and
the environment.

Cambridge IGCSE Chemistry 0620 syllabus for 2020 and 2021. Syllabus overview
Content overview
Candidates study the following topics:
1 The particulate nature of matter
2 Experimental techniques
3 Atoms, elements and compounds
4 Stoichiometry
5 Electricity and chemistry
6 Chemical energetics
7 Chemical reactions
8 Acids, bases and salts
9 The Periodic Table
10 Metals
11 Air and water
12 Sulfur
13 Carbonates
14 Organic chemistry
Support for Cambridge IGCSE Chemistry

Our School Support Hub www.cambridgeinternational.org/support provides Cambridge schools with a
secure site for downloading specimen and past question papers, mark schemes, grade thresholds and other
curriculum resources specific to this syllabus. The School Support Hub community offers teachers the
opportunity to connect with each other and to ask questions related to the syllabus.

Assessment overview
All candidates take three papers.
Candidates who have studied the Core subject content, or who are expected to achieve a grade D or below should
be entered for Paper 1, Paper 3 and either Paper 5 or Paper 6. These candidates will be eligible for grades C to G.
Candidates who have studied the Extended subject content (Core and Supplement), and who are expected to
achieve a grade C or above should be entered for Paper 2, Paper 4 and either Paper 5 or Paper 6. These candidates
will be eligible for grades A* to G.
Core candidates take: Extended candidates take:
Paper 1 45 minutes Paper 2 45 minutes

Multiple Choice 30% Multiple Choice 30%
40 marks 40 marks
40 four-choice multiple-choice questions 40 four-choice multiple-choice questions
Questions will be based on the Core subject Questions will be based on the Extended
content subject content (Core and Supplement)
Assessing grades C–G Assessing grades A*–G
Externally assessed Externally assessed
and Core candidates take: and Extended candidates take:
Paper 3 1 hour 15 minutes Paper 4 1 hour 15 minutes

Theory 50% Theory 50%
80 marks 80 marks
Short-answer and structured questions Short-answer and structured questions
Questions will be based on the Core subject Questions will be based on the Extended
content subject content (Core and Supplement)
Assessing grades C–G Assessing grades A*–G
All candidates take

either: or:
Paper 5 1 hour 15 minutes Paper 6 1 hour

Practical Test 20% Alternative to Practical 20%
40 marks 40 marks
Questions will be based on the experimental Questions will be based on the experimental
skills in Section 4 skills in Section 4
Assessing grades A*–G Assessing grades A*–G

Assessment objectives
The assessment objectives (AOs) are:
AO1 Knowledge with understanding
Candidates should be able to demonstrate knowledge and understanding of:

•• scientific phenomena, facts, laws, definitions, concepts and theories
•• scientific vocabulary, terminology and conventions (including symbols, quantities and units)
•• scientific instruments and apparatus, including techniques of operation and aspects of safety
•• scientific and technological applications with their social, economic and environmental implications.
Subject content defines the factual material that candidates may be required to recall and explain. Candidates will
also be asked questions which require them to apply this material to unfamiliar contexts and to apply knowledge
from one area of the syllabus to another.
Questions testing this objective will often begin with one of the following words: define, state, describe, explain
(using your knowledge and understanding) or outline (see the Glossary of terms used in science papers).
AO2 Handling information and problem solving
Candidates should be able, in words or using other written forms of presentation (i.e. symbolic, graphical and
numerical), to:
•• locate, select, organise and present information from a variety of sources
•• translate information from one form to another
•• manipulate numerical and other data
•• use information to identify patterns, report trends and draw inferences
•• present reasoned explanations for phenomena, patterns and relationships
•• make predictions and hypotheses
•• solve problems, including some of a quantitative nature.
Questions testing these skills may be based on information that is unfamiliar to candidates, requiring them to apply
the principles and concepts from the syllabus to a new situation, in a logical, deductive way.
Questions testing these skills will often begin with one of the following words: predict, suggest, calculate or
determine (see the Glossary of terms used in science papers).
AO3 Experimental skills and investigations
Candidates should be able to:

•• demonstrate knowledge of how to safely use techniques, apparatus and materials (including following a
sequence of instructions where appropriate)
•• plan experiments and investigations
•• make and record observations, measurements and estimates
•• interpret and evaluate experimental observations and data
•• evaluate methods and suggest possible improvements.

Weighting for assessment objectives

The approximate weightings allocated to each of the assessment objectives (AOs) are summarised below.
Assessment objectives as a percentage of the qualification
Assessment objective Weighting in IGCSE %
AO1 Knowledge with understanding 50
AO2 Handling information and problem solving 30
AO3 Experimental skills and investigations 20
Assessment objectives as a percentage of each component
Assessment objective Weighting in components %
Papers 1 and 2 Papers 3 and 4 Papers 5 and 6
AO1 Knowledge with understanding 63 63 0
AO2 Handling information and problem solving 37 37 0
AO3 Experimental skills and investigations 0 0 100

3 Subject content
All candidates should be taught the Core subject content. Candidates who are only taught the Core subject content
can achieve a maximum of grade C. Candidates aiming for grades A* to C should be taught the Extended subject
content. The Extended subject content includes both the Core and the Supplement.
Scientific subjects are, by their nature, experimental. Learners should pursue a fully integrated course which allows
them to develop their practical skills by carrying out practical work and investigations within all of the topics listed.
1 The particulate nature of matter

1.1 The particulate nature of matter
Core Supplement
•• State the distinguishing properties of solids,
liquids and gases
•• Describe the structure of solids, liquids and gases
in terms of particle separation, arrangement and
types of motion
•• Describe changes of state in terms of melting, •• Explain changes of state in terms of the kinetic
boiling, evaporation, freezing, condensation and theory
sublimation
•• Describe qualitatively the pressure and
temperature of a gas in terms of the motion of
its particles
•• Show an understanding of the random motion •• Describe and explain Brownian motion in terms
of particles in a suspension (sometimes known of random molecular bombardment
as Brownian motion) as evidence for the kinetic •• State evidence for Brownian motion
particle (atoms, molecules or ions) model of
matter
•• Describe and explain diffusion •• Describe and explain dependence of rate of
diffusion on molecular mass
2 Experimental techniques
2.1 Measurement
Core
•• Name appropriate apparatus for the
measurement of time, temperature, mass
and volume, including burettes, pipettes and
measuring cylinders

Cambridge IGCSE Chemistry 0620 syllabus for 2020 and 2021. Subject content
2.2 Purity
2.2.1 Criteria of purity
Core Supplement
•• Demonstrate knowledge and understanding of •• Interpret simple chromatograms, including the
paper chromatography use of Rf values
•• Interpret simple chromatograms •• Outline how chromatography techniques can
•• Identify substances and assess their purity from be applied to colourless substances by exposing
melting point and boiling point information chromatograms to substances called locating
agents. (Knowledge of specific locating agents is
•• Understand the importance of purity in
not required.)
substances in everyday life, e.g. foodstuffs and
drugs
2.2.2 Methods of purification

Core
•• Describe and explain methods of purification
by the use of a suitable solvent, filtration,
crystallisation and distillation (including use of
a fractionating column). (Refer to the fractional
distillation of petroleum in section 14.2 and
products of fermentation in section 14.6.)
•• Suggest suitable purification techniques, given
information about the substances involved
3 Atoms, elements and compounds

3.1 Atomic structure and the Periodic Table
Core Supplement
•• State the relative charges and approximate
relative masses of protons, neutrons and
electrons
•• Define proton number (atomic number) as the
number of protons in the nucleus of an atom
•• Define nucleon number (mass number) as the
total number of protons and neutrons in the
nucleus of an atom
•• Use proton number and the simple structure of
atoms to explain the basis of the Periodic Table
(see section 9), with special reference to the
elements of proton number 1 to 20
•• Define isotopes as atoms of the same element •• Understand that isotopes have the same
which have the same proton number but a properties because they have the same number
different nucleon number of electrons in their outer shell
•• State the two types of isotopes as being
radioactive and non-radioactive continued

3.1 Atomic structure and the Periodic Table continued

Core
•• State one medical and one industrial use of
radioactive isotopes
•• Describe the build-up of electrons in ‘shells’
and understand the significance of the noble
gas electronic structures and of the outer
shell electrons. (The ideas of the distribution
of electrons in s and p orbitals and in d block
elements are not required.)
Note: a copy of the Periodic Table, as shown in the
Appendix, will be available in Papers 1, 2, 3 and 4.
3.2 Structure and bonding

3.2.1 Bonding: the structure of matter
Core
•• Describe the differences between elements,
mixtures and compounds, and between metals
and non-metals
•• Describe an alloy, such as brass, as a mixture of a
metal with other elements
3.2.2 Ions and ionic bonds

Core Supplement
•• Describe the formation of ions by electron loss •• Describe the formation of ionic bonds between
or gain metallic and non-metallic elements
•• Describe the formation of ionic bonds between •• Describe the lattice structure of ionic compounds
elements from Groups I and VII as a regular arrangement of alternating positive
and negative ions
3.2.3 Molecules and covalent bonds

Core Supplement
•• Describe the formation of single covalent bonds •• Describe the electron arrangement in more
in H2, Cl2, H2O, CH4, NH3 and HCl as the sharing complex covalent molecules such as N2, C2H4,
of pairs of electrons leading to the noble gas CH3OH and CO2
configuration •• Explain the differences in melting point and
•• Describe the differences in volatility, solubility boiling point of ionic and covalent compounds in
and electrical conductivity between ionic and terms of attractive forces
covalent compounds

3.2.4 Macromolecules
Core Supplement
•• Describe the giant covalent structures of graphite •• Describe the macromolecular structure of
and diamond silicon(IV) oxide (silicon dioxide)
•• Relate their structures to their uses, e.g. graphite •• Describe the similarity in properties between
as a lubricant and a conductor, and diamond in diamond and silicon(IV) oxide, related to their
cutting tools structures
3.2.5 Metallic bonding

Supplement
•• Describe metallic bonding as a lattice of positive
ions in a ‘sea of electrons’ and use this to describe
the electrical conductivity and malleability of
metals
4 Stoichiometry
4.1 Stoichiometry
Core Supplement
•• Use the symbols of the elements and write the •• Determine the formula of an ionic compound
formulae of simple compounds from the charges on the ions present
•• Deduce the formula of a simple compound from •• Construct equations with state symbols,
the relative numbers of atoms present including ionic equations
•• Deduce the formula of a simple compound from •• Deduce the balanced equation for a chemical
a model or a diagrammatic representation reaction, given relevant information
•• Construct word equations and simple balanced
chemical equations
•• Define relative atomic mass, Ar, as the average
mass of naturally occurring atoms of an element
on a scale where the 12C atom has a mass of
exactly 12 units
•• Define relative molecular mass, Mr, as the sum
of the relative atomic masses. (Relative formula
mass or Mr will be used for ionic compounds.)
(Calculations involving reacting masses in simple
proportions may be set. Calculations will not
involve the mole concept.)

4.2 The mole concept

Supplement
•• Define the mole and the Avogadro constant
•• Use the molar gas volume, taken as 24 dm3 at
room temperature and pressure
•• Calculate stoichiometric reacting masses,
volumes of gases and solutions, and
concentrations of solutions expressed in g / dm3
and mol / dm3. (Calculations involving the idea of
limiting reactants may be set. Questions on the
gas laws and the conversion of gaseous volumes
to different temperatures and pressures will not
be set.)
•• Calculate empirical formulae and molecular
formulae
•• Calculate percentage yield and percentage purity
5 Electricity and chemistry

5.1 Electricity and chemistry
Core Supplement
•• Define electrolysis as the breakdown of an ionic •• Relate the products of electrolysis to the
compound, molten or in aqueous solution, by the electrolyte and electrodes used, exemplified
passage of electricity by the specific examples in the Core together
•• Describe the electrode products and the with aqueous copper(II) sulfate using carbon
observations made during the electrolysis of: electrodes and using copper electrodes (as used
in the refining of copper)
–– molten lead(II) bromide
•• Describe electrolysis in terms of the ions present
–– concentrated hydrochloric acid
and reactions at the electrodes in the examples
–– concentrated aqueous sodium chloride given
–– dilute sulfuric acid
between inert electrodes (platinum or carbon)
•• State the general principle that metals or
hydrogen are formed at the negative electrode
(cathode), and that non-metals (other than
hydrogen) are formed at the positive electrode
(anode)
•• Predict the products of the electrolysis of a •• Predict the products of electrolysis of a specified
specified binary compound in the molten state halide in dilute or concentrated aqueous solution
•• Describe the electroplating of metals •• Construct ionic half-equations for reactions at
•• Outline the uses of electroplating the cathode
continued

5.1 Electricity and chemistry continued

Core Supplement
•• Describe the reasons for the use of copper and •• Describe the transfer of charge during electrolysis
(steel-cored) aluminium in cables, and why to include:
plastics and ceramics are used as insulators –– the movement of electrons in the metallic
conductor
–– the removal or addition of electrons from the
external circuit at the electrodes
–– the movement of ions in the electrolyte
•• Describe the production of electrical energy from
simple cells, i.e. two electrodes in an electrolyte.
(This should be linked with the reactivity series in
section 10.2 and redox in section 7.4.)
•• Describe, in outline, the manufacture of:
–– aluminium from pure aluminium oxide in
molten cryolite (refer to section 10.3)
–– chlorine, hydrogen and sodium hydroxide
from concentrated aqueous sodium chloride
(Starting materials and essential conditions
should be given but not technical details or
diagrams.)
6 Chemical energetics
6.1 Energetics of a reaction
Core Supplement
•• Describe the meaning of exothermic and •• Describe bond breaking as an endothermic
endothermic reactions process and bond forming as an exothermic
•• Interpret energy level diagrams showing process
exothermic and endothermic reactions •• Draw and label energy level diagrams for
exothermic and endothermic reactions using data
provided
•• Calculate the energy of a reaction using bond
energies
6.2 Energy transfer

Core Supplement
•• Describe the release of heat energy by burning •• Describe the use of hydrogen as a fuel reacting
fuels with oxygen to generate electricity in a fuel cell.
•• State the use of hydrogen as a fuel (Details of the construction and operation of a
fuel cell are not required.)
•• Describe radioactive isotopes, such as 235U, as a
source of energy

7 Chemical reactions
7.1 Physical and chemical changes
Core
•• Identify physical and chemical changes, and
understand the differences between them
7.2 Rate (speed) of reaction

Core Supplement
•• Describe and explain the effect of concentration, •• Devise and evaluate a suitable method for
particle size, catalysts (including enzymes) and investigating the effect of a given variable on the
temperature on the rate of reactions rate of a reaction
•• Describe the application of the above factors to
the danger of explosive combustion with fine
powders (e.g. flour mills) and gases (e.g. methane
in mines)
•• Demonstrate knowledge and understanding of a •• Describe and explain the effects of temperature
practical method for investigating the rate of a and concentration in terms of collisions between
reaction involving gas evolution reacting particles. (An increase in temperature
•• Interpret data obtained from experiments causes an increase in collision rate and more of
concerned with rate of reaction the colliding molecules have sufficient energy
(activation energy) to react whereas an increase
Note: Candidates should be encouraged to use the
in concentration only causes an increase in
term rate rather than speed.
collision rate.)
•• Describe and explain the role of light in
photochemical reactions and the effect of light
on the rate of these reactions. (This should be
linked to section 14.4.)
•• Describe the use of silver salts in photography as
a process of reduction of silver ions to silver; and
photosynthesis as the reaction between carbon
dioxide and water in the presence of chlorophyll
and sunlight (energy) to produce glucose and
oxygen
7.3 Reversible reactions

Core Supplement
•• Understand that some chemical reactions can •• Predict the effect of changing the conditions
be reversed by changing the reaction conditions. (concentration, temperature and pressure) on
(Limited to the effects of heat and water on other reversible reactions
hydrated and anhydrous copper(II) sulfate and •• Demonstrate knowledge and understanding of
cobalt(II) chloride.) (Concept of equilibrium is the concept of equilibrium
not required.)

7.4 Redox
Core Supplement
•• Define oxidation and reduction in terms of oxygen •• Define redox in terms of electron transfer
loss/gain. (Oxidation state limited to its use •• Identify redox reactions by changes in oxidation
to name ions, e.g. iron(II), iron(III), copper(II), state and by the colour changes involved when
manganate(VII).) using acidified potassium manganate(VII), and
potassium iodide. (Recall of equations involving
KMnO4 is not required.)
•• Define oxidising agent as a substance which
oxidises another substance during a redox
reaction. Define reducing agent as a substance
which reduces another substance during a redox
reaction.
•• Identify oxidising agents and reducing agents
from simple equations
8 Acids, bases and salts

8.1 The characteristic properties of acids and bases
Core Supplement
•• Describe the characteristic properties of acids •• Define acids and bases in terms of proton
as reactions with metals, bases, carbonates and transfer, limited to aqueous solutions
effect on litmus and methyl orange
•• Describe the characteristic properties of bases as •• Describe the meaning of weak and strong acids
reactions with acids and with ammonium salts and bases
and effect on litmus and methyl orange
•• Describe neutrality and relative acidity and
alkalinity in terms of pH measured using
universal indicator paper (whole numbers only)
•• Describe and explain the importance of
controlling acidity in soil
8.2 Types of oxides

Core Supplement
•• Classify oxides as either acidic or basic, related to •• Further classify other oxides as neutral or
metallic and non-metallic character amphoteric

8.3 Preparation of salts

Core Supplement
•• Demonstrate knowledge and understanding of •• Demonstrate knowledge and understanding of
preparation, separation and purification of salts the preparation of insoluble salts by precipitation
as examples of some of the techniques specified •• Suggest a method of making a given salt from
in section 2.2.2 and the reactions specified in a suitable starting material, given appropriate
section 8.1 information
8.4 Identification of ions and gases

Core
•• Describe the following tests to identify:
aqueous cations:
aluminium, ammonium, calcium, chromium(III),
copper(II), iron(II), iron(III) and zinc (using
aqueous sodium hydroxide and aqueous
ammonia as appropriate). (Formulae of complex
ions are not required.)
cations:
use of the flame test to identify lithium, sodium,
potassium and copper(II)
anions:
carbonate (by reaction with dilute acid and then
limewater), chloride, bromide and iodide (by
reaction under acidic conditions with aqueous
silver nitrate), nitrate (by reduction with
aluminium), sulfate (by reaction under acidic
conditions with aqueous barium ions) and sulfite
(by reaction with dilute acids and then aqueous
potassium manganate(VII))
gases:
ammonia (using damp red litmus paper),
carbon dioxide (using limewater), chlorine
(using damp litmus paper), hydrogen (using
lighted splint), oxygen (using a glowing splint),
and sulfur dioxide (using aqueous potassium
manganate(VII))

9 The Periodic Table

9.1 The Periodic Table
Core
•• Describe the Periodic Table as a method of
classifying elements and its use to predict
properties of elements
9.2 Periodic trends

Core Supplement
•• Describe the change from metallic to non- •• Describe and explain the relationship between
metallic character across a period Group number, number of outer shell electrons
and metallic/non-metallic character
9.3 Group properties

Core Supplement
•• Describe lithium, sodium and potassium in •• Identify trends in Groups, given information
Group I as a collection of relatively soft metals about the elements concerned
showing a trend in melting point, density and
reaction with water
•• Predict the properties of other elements in
Group I, given data, where appropriate
•• Describe the halogens, chlorine, bromine and
iodine in Group VII, as a collection of diatomic
non-metals showing a trend in colour and density
and state their reaction with other halide ions
•• Predict the properties of other elements in
Group VII, given data where appropriate
9.4 Transition elements

Core Supplement
•• Describe the transition elements as a collection •• Know that transition elements have variable
of metals having high densities, high melting oxidation states
points and forming coloured compounds, and
which, as elements and compounds, often act as
catalysts

9.5 Noble gases

Core
•• Describe the noble gases, in Group VIII or 0, as
being unreactive, monoatomic gases and explain
this in terms of electronic structure
•• State the uses of the noble gases in providing an
inert atmosphere, i.e. argon in lamps, helium for
filling balloons
10 Metals
10.1 Properties of metals
Core
•• List the general physical properties of metals
•• Describe the general chemical properties of
metals, e.g. reaction with dilute acids and
reaction with oxygen
•• Explain in terms of their properties why alloys are
used instead of pure metals
•• Identify representations of alloys from diagrams
of structure
10.2 Reactivity series

Core Supplement
•• Place in order of reactivity: potassium, sodium, •• Describe the reactivity series as related to the
calcium, magnesium, zinc, iron, (hydrogen) and tendency of a metal to form its positive ion,
copper, by reference to the reactions, if any, of illustrated by its reaction, if any, with:
the metals with: –– the aqueous ions
–– water or steam –– the oxides
–– dilute hydrochloric acid of the other listed metals
and the reduction of their oxides with carbon •• Describe and explain the action of heat on the
hydroxides, carbonates and nitrates of the listed
metals
•• Account for the apparent unreactivity of
aluminium in terms of the oxide layer which
adheres to the metal
•• Deduce an order of reactivity from a given set of
experimental results

10.3 Extraction of metals

Core Supplement
•• Describe the ease in obtaining metals from their •• Describe in outline, the extraction of zinc from
ores by relating the elements to the reactivity zinc blende
series
•• Describe and state the essential reactions in the
extraction of iron from hematite
•• Describe the conversion of iron into steel using
basic oxides and oxygen
•• Know that aluminium is extracted from the ore
bauxite by electrolysis
•• Discuss the advantages and disadvantages •• Describe in outline, the extraction of aluminium
of recycling metals, limited to iron/steel and from bauxite including the role of cryolite and
aluminium the reactions at the electrodes
10.4 Uses of metals

Core Supplement
•• Name the uses of aluminium: •• Explain the uses of zinc for galvanising and for
–– in the manufacture of aircraft because of its making brass
strength and low density
–– in food containers because of its resistance
to corrosion
•• Name the uses of copper related to its properties
(electrical wiring and in cooking utensils)
•• Name the uses of mild steel (car bodies and •• Describe the idea of changing the properties of
machinery) and stainless steel (chemical plant iron by the controlled use of additives to form
and cutlery) steel alloys
11 Air and water

11.1 Water
Core Supplement
•• Describe chemical tests for water using cobalt(II) •• Discuss the implications of an inadequate supply
chloride and copper(II) sulfate of water, limited to safe water for drinking and
•• Describe, in outline, the treatment of the water water for irrigating crops
supply in terms of filtration and chlorination
•• Name some of the uses of water in industry and
in the home

11.2 Air
Core Supplement
•• State the composition of clean, dry air as being •• Describe the separation of oxygen and nitrogen
approximately 78% nitrogen, 21% oxygen and from liquid air by fractional distillation
the remainder as being a mixture of noble gases
and carbon dioxide
•• Name the common pollutants in the air as
being carbon monoxide, sulfur dioxide, oxides of
nitrogen and lead compounds
•• State the source of each of these pollutants: •• Describe and explain the presence of oxides
–– carbon monoxide from the incomplete of nitrogen in car engines and their catalytic
combustion of carbon-containing substances removal
–– sulfur dioxide from the combustion of fossil
fuels which contain sulfur compounds
(leading to ‘acid rain’)
–– oxides of nitrogen from car engines
–– lead compounds from leaded petrol
•• State the adverse effect of these common
pollutants on buildings and on health and discuss
why these pollutants are of global concern
•• State the conditions required for the rusting of
iron
•• Describe and explain methods of rust prevention, •• Describe and explain sacrificial protection in
specifically paint and other coatings to exclude terms of the reactivity series of metals and
oxygen galvanising as a method of rust prevention
11.3 Nitrogen and fertilisers

Core Supplement
•• Describe the need for nitrogen-, phosphorus- and •• Describe and explain the essential conditions
potassium-containing fertilisers for the manufacture of ammonia by the Haber
•• Describe the displacement of ammonia from its process including the sources of the hydrogen
salts and nitrogen, i.e. hydrocarbons or steam and air

11.4 Carbon dioxide and methane

Core Supplement
•• State that carbon dioxide and methane are
greenhouse gases and explain how they may
contribute to climate change
•• State the formation of carbon dioxide: •• Describe the carbon cycle, in simple terms, to
–– as a product of complete combustion of include the processes of combustion, respiration
carbon-containing substances and photosynthesis
–– as a product of respiration
–– as a product of the reaction between an acid
and a carbonate
–– from the thermal decomposition of a
carbonate
•• State the sources of methane, including
decomposition of vegetation and waste gases
from digestion in animals
12 Sulfur
12.1 Sulfur
Core Supplement
•• Name some sources of sulfur •• Describe the manufacture of sulfuric acid by the
•• Name the use of sulfur in the manufacture of Contact process, including essential conditions
sulfuric acid and reactions
•• State the uses of sulfur dioxide as a bleach in the •• Describe the properties and uses of dilute and
manufacture of wood pulp for paper and as a concentrated sulfuric acid
food preservative (by killing bacteria)
13 Carbonates
13.1 Carbonates
Core
•• Describe the manufacture of lime
(calcium oxide) from calcium carbonate
(limestone) in terms of thermal decomposition
•• Name some uses of lime and slaked lime
such as in treating acidic soil and neutralising
acidic industrial waste products, e.g. flue gas
desulfurisation
•• Name the uses of calcium carbonate in the
manufacture of iron and cement

14 Organic chemistry
14.1 Names of compounds
Core Supplement
•• Name and draw the structures of methane, •• Name and draw the structures of the unbranched
ethane, ethene, ethanol, ethanoic acid and the alkanes, alkenes (not cis-trans), alcohols and
products of the reactions stated in sections acids containing up to four carbon atoms per
14.4–14.6 molecule
•• State the type of compound present, given a •• Name and draw the structural formulae of the
chemical name ending in ‑ane, ‑ene, ‑ol, or ‑oic esters which can be made from unbranched
acid or a molecular structure alcohols and carboxylic acids, each containing up
to four carbon atoms
14.2 Fuels
Core
•• Name the fuels: coal, natural gas and petroleum
•• Name methane as the main constituent of
natural gas
•• Describe petroleum as a mixture of hydrocarbons
and its separation into useful fractions by
fractional distillation
•• Describe the properties of molecules within a
fraction
•• Name the uses of the fractions as:
–– refinery gas for bottled gas for heating and
cooking
–– gasoline fraction for fuel (petrol) in cars
–– naphtha fraction for making chemicals
–– kerosene/paraffin fraction for jet fuel
–– diesel oil/gas oil for fuel in diesel engines
–– fuel oil fraction for fuel for ships and home
heating systems
–– lubricating fraction for lubricants, waxes and
polishes
–– bitumen for making roads

14.3 Homologous series

Core Supplement
•• Describe the concept of homologous series as •• Describe the general characteristics of a
a ‘family’ of similar compounds with similar homologous series
chemical properties due to the presence of the •• Recall that the compounds in a homologous
same functional group series have the same general formula
•• Describe and identify structural isomerism
14.4 Alkanes
Core Supplement
•• Describe the properties of alkanes (exemplified •• Describe substitution reactions of alkanes with
by methane) as being generally unreactive, chlorine
except in terms of burning
•• Describe the bonding in alkanes
14.5 Alkenes
Core Supplement
•• Describe the manufacture of alkenes and of •• Describe the properties of alkenes in terms of
hydrogen by cracking addition reactions with bromine, hydrogen and
•• Distinguish between saturated and unsaturated steam
hydrocarbons:
–– from molecular structures
–– by reaction with aqueous bromine
•• Describe the formation of poly(ethene) as an
example of addition polymerisation of monomer
units
14.6 Alcohols
Core Supplement
•• Describe the manufacture of ethanol by •• Outline the advantages and disadvantages of
fermentation and by the catalytic addition of these two methods of manufacturing ethanol
steam to ethene
•• Describe the properties of ethanol in terms of
burning
•• Name the uses of ethanol as a solvent and as a
fuel

14.7 Carboxylic acids

Core Supplement
•• Describe the properties of •• Describe the formation of ethanoic acid by the oxidation
aqueous ethanoic acid of ethanol by fermentation and with acidified
potassium manganate(VII)
•• Describe ethanoic acid as a typical weak acid
•• Describe the reaction of a carboxylic acid with an alcohol in the
presence of a catalyst to give an ester
14.8 Polymers
14.8.1 Polymers
Core Supplement
•• Define polymers as large •• Understand that different polymers have different units and/or
molecules built up from small different linkages
units (monomers)
14.8.2 Synthetic polymers

Core Supplement
•• Name some typical uses of •• Explain the differences between condensation and addition
plastics and of man-made fibres polymerisation
such as nylon and Terylene •• Deduce the structure of the polymer product from a given
•• Describe the pollution problems alkene and vice versa
caused by non-biodegradable •• Describe the formation of nylon (a polyamide) and Terylene
plastics (a polyester) by condensation polymerisation, the structure of
nylon being represented as:
O O O O O
C C N N C C N N C
H H H H
and the structure of Terylene as:
O O O O
C C O O C C O O
(Details of manufacture and mechanisms of these

polymerisations are not required.)

14.8.3 Natural polymers

Core Supplement
•• Name proteins and carbohydrates •• Describe proteins as possessing the same (amide) linkages as
as constituents of food nylon but with different units
•• Describe the structure of proteins as:
H O H O
N C N C N C
H O
•• Describe the hydrolysis of proteins to amino acids. (Structures

and names are not required.)
•• Describe complex carbohydrates in terms of a large number of
sugar units, considered as HO OH,
joined together by condensation polymerisation, e.g.
O O O O
•• Describe the hydrolysis of complex carbohydrates (e.g. starch),
by acids or enzymes to give simple sugars
•• Describe the fermentation of simple sugars to produce ethanol
(and carbon dioxide). (Candidates will not be expected to give
the molecular formulae of sugars.)
•• Describe, in outline, the usefulness of chromatography in
separating and identifying the products of hydrolysis of
carbohydrates and proteins

4 Details of the assessment
All candidates take three papers.
Core Assessment
Core candidates take the following papers that have questions based on the Core subject content only:
Paper 1 – Multiple Choice (Core)
45 minutes, 40 marks
Forty compulsory multiple-choice items of the four-choice type. This paper tests assessment objectives AO1
and AO2.
Paper 3 – Theory (Core)
1 hour 15 minutes, 80 marks
Short-answer and structured questions testing assessment objectives AO1 and AO2.
Extended Assessment
Extended candidates take the following papers that have questions based on the Core and Supplement subject
content:
Paper 2 – Multiple Choice (Extended)
45 minutes, 40 marks
Forty compulsory multiple-choice items of the four-choice type. This paper tests assessment objectives AO1
and AO2.
Paper 4 – Theory (Extended)
Short-answer and structured questions testing assessment objectives AO1 and AO2.

Cambridge IGCSE Chemistry 0620 syllabus for 2020 and 2021. Details of the assessment
Practical Assessment
All candidates take one practical component from a choice of two:
Paper 5 – Practical Test
This paper tests assessment objective AO3 in a practical context.
or
Paper 6 – Alternative to Practical Test
1 hour, 40 marks
This paper tests assessment objective AO3 in a written paper.
Whichever practical paper you choose please be aware that:

•• they test the same assessment objective, AO3
•• they require the same experimental skills to be learned and developed
•• the same sequence of practical activities is appropriate.
Candidates must not use textbooks or any of their course notes in the practical component.
Questions in the practical papers are structured to assess performance across the grade ranges A* to G. The
information candidates need to answer the questions is in the question paper itself or the experimental context and
skills listed below. The questions do not assess specific syllabus content.
Experimental skills tested in Paper 5 Practical Test and Paper 6 Alternative to Practical
Candidates may be asked questions on the following experimental contexts:
•• simple quantitative experiments involving the measurement of volumes and/or masses
•• rates (speeds) of reaction
•• measurement of temperature based on a thermometer with 1 °C graduations
•• problems of an investigatory nature, possibly including suitable organic compounds
•• filtration
•• electrolysis
•• identification of ions and gases (Paper 5 will include notes on qualitative analysis for the use of candidates in
the examination).
Candidates may be required to do the following:

•• take and record readings from apparatus, including:
–– reading a scale with appropriate accuracy and precision
–– interpolating between scale divisions
–– taking repeated measurements, where appropriate
•• describe, explain or comment on experimental arrangements and techniques

•• complete tables of data, and process data, using a calculator where necessary
•• draw an appropriate conclusion, justifying it by reference to the data and using an appropriate explanation
•• interpret and evaluate observations and experimental data
•• plot graphs and/or interpret graphical information
•• identify sources of error and suggest possible improvements in procedures
•• plan an experiment or investigation, including making reasoned predictions of expected results and suggesting
suitable apparatus and techniques.
Teaching experimental skills

We expect you to look for suitable opportunities to embed practical techniques and investigative work throughout
the course.
The best way to prepare candidates for these papers is to integrate practical work fully into the course so that it
becomes a normal part of your teaching. Practical work helps candidates to:
•• develop a deeper understanding of the syllabus topics
•• learn to appreciate the way in which scientific theories are developed and tested
•• develop experimental skills and positive scientific attitudes such as objectivity, integrity, cooperation,
enquiry and inventiveness.
Apparatus list
This list contains the items you will need for teaching the experimental skills needed for both practical papers, as
well as the Paper 5 exam. It is not exhaustive and does not include standard equipment such as Bunsen burners or
tripods. The Confidential Instructions we send you before the Paper 5 exam will give the detailed requirements for
the exam.
•• a burette, 50 cm3
•• a pipette, 25 cm3
•• a pipette filler
•• two conical flasks, within the range 150 cm3 to 250 cm3
•• measuring cylinder, 50 cm3, 25 cm3, 10 cm3
•• a filter funnel
•• beaker, squat form with lip, 250 cm3 and 100 cm3
•• a thermometer, –10 °C to + 110 °C at 1 °C graduations
•• a polystyrene or other plastic beaker of approximate capacity 150 cm3
•• clocks (or wall-clock) to measure to an accuracy of 1 s (where clocks are specified, candidates may use their
own wrist-watch if they prefer)
•• wash bottle
•• test-tubes (Pyrex or hard glass), approximately 125 mm × 16 mm
•• boiling tubes, approximately 150 mm × 25 mm
•• stirring rod

Notes for use in qualitative analysis
Tests for anions

anion test test result
carbonate (CO32–) add dilute acid effervescence, carbon dioxide produced
chloride (Cl –) acidify with dilute nitric acid, then add white ppt.
[in solution] aqueous silver nitrate
bromide (Br–) acidify with dilute nitric acid, then add cream ppt.
iodide (I–) acidify with dilute nitric acid, then add yellow ppt.
nitrate (NO3–) add aqueous sodium hydroxide, then ammonia produced
[in solution] aluminium foil; warm carefully
sulfate (SO42–) acidify, then add aqueous barium nitrate white ppt.
[in solution]
sulfite (SO32–) add dilute hydrochloric acid, warm gently sulfur dioxide produced will turn acidified
and test for the presence of sulfur dioxide aqueous potassium manganate(VII) from
purple to colourless

Tests for aqueous cations

cation effect of aqueous sodium hydroxide effect of aqueous ammonia
aluminium (Al 3+) white ppt., soluble in excess, giving a white ppt., insoluble in excess
colourless solution
ammonium (NH4+) ammonia produced on warming –
calcium (Ca2+) white ppt., insoluble in excess no ppt. or very slight white ppt.
chromium(III) (Cr3+) green ppt., soluble in excess grey-green ppt., insoluble in excess
copper(II) (Cu2+) light blue ppt., insoluble in excess light blue ppt., soluble in excess, giving a
dark blue solution
iron(II) (Fe2+) green ppt., insoluble in excess green ppt., insoluble in excess
iron(III) (Fe3+) red-brown ppt., insoluble in excess red-brown ppt., insoluble in excess
zinc (Zn2+) white ppt., soluble in excess, giving a white ppt., soluble in excess, giving a
colourless solution colourless solution
Tests for gases

gas test and test result
ammonia (NH3) turns damp red litmus paper blue
carbon dioxide (CO2) turns limewater milky

chlorine (Cl 2) bleaches damp litmus paper
hydrogen (H2) ‘pops’ with a lighted splint
oxygen (O2) relights a glowing splint
sulfur dioxide (SO2) turns acidified aqueous potassium manganate(VII) from purple to colourless
Flame tests for metal ions

metal ion flame colour
lithium (Li+) red
sodium (Na+) yellow
potassium (K+) lilac
copper(II) (Cu2+) blue-green

Glossary of terms used in science papers

This glossary (which is relevant only to science subjects) will prove helpful to candidates as a guide, but it is neither
exhaustive nor definitive. The glossary has been deliberately kept brief, not only with respect to the number of
terms included, but also to the descriptions of their meanings. Candidates should appreciate that the meaning of a
term must depend, in part, on its context.
1 Define (the term(s) … ) is intended literally, only a formal statement or equivalent paraphrase being required.
2
What do you understand by/What is meant by (the term(s) … ) normally implies that a definition should be given,
together with some relevant comment on the significance or context of the term(s) concerned, especially where
two or more terms are included in the question. The amount of supplementary comment intended should be
interpreted in the light of the indicated mark value.
3 State implies a concise answer with little or no supporting argument (e.g. a numerical answer that can readily
be obtained ‘by inspection’).
4 List requires a number of points, generally each of one word, with no elaboration. Where a given number of
points is specified this should not be exceeded.
5 (a) Explain may imply reasoning or some reference to theory, depending on the context. It is another way of
asking candidates to give reasons. The candidate needs to leave the examiner in no doubt why something
happens.
(b) G
ive a reason/Give reasons is another way of asking candidates to explain why something happens.
6 Describe requires the candidate to state in words (using diagrams where appropriate) the main points.
Describe and explain may be coupled, as may state and explain.
7 Discuss requires the candidate to give a critical account of the points involved.
8 Outline implies brevity (i.e. restricting the answer to giving essentials).
9 Predict implies that the candidate is expected to make a prediction not by recall but by making a logical
connection between other pieces of information.
10 Deduce implies that the candidate is not expected to produce the required answer by recall but by making a
logical connection between other pieces of information.
11 Suggest is used in two main contexts, i.e. either to imply that there is no unique answer (e.g. in chemistry, two
or more substances may satisfy the given conditions describing an ‘unknown’), or to imply that candidates are
expected to apply their general knowledge of the subject to a ‘novel’ situation, one that may be formally ‘not in
the syllabus’ – many data response and problem-solving questions are of this type.
12 Find is a general term that may variously be interpreted as calculate, measure, determine, etc.
13 Calculate is used when a numerical answer is required. In general, working should be shown, especially where
two or more steps are involved.
14 Measure implies that the quantity concerned can be directly obtained from a suitable measuring instrument
(e.g. length using a rule, or mass using a balance).
15 Determine often implies that the quantity concerned cannot be measured directly but is obtained from a graph
or by calculation.
16 Estimate implies a reasoned order of magnitude statement or calculation of the quantity concerned, making
such simplifying assumptions as may be necessary about points of principle and about the values of quantities
not otherwise included in the question.
17 Sketch, when applied to graph work, implies that the shape and/or position of the curve need only be
qualitatively correct, but candidates should be aware that, depending on the context, some quantitative
aspects may be looked for (e.g. passing through the origin, having an intercept).
In diagrams, sketch implies that simple, free-hand drawing is acceptable; nevertheless, care should be taken
over proportions and the clear exposition of important details.

34
5 Appendix
The Periodic Table

Group
I II III IV V VI VII VIII
1 2
H He
hydrogen helium
Key 1 4
3 4 atomic number 5 6 7 8 9 10
Li Be atomic symbol B C N O F Ne
www.cambridgeinternational.org/igcse
lithium beryllium name boron carbon nitrogen oxygen fluorine neon
7 9 relative atomic mass 11 12 14 16 19 20
11 12 13 14 15 16 17 18
Na Mg Al Si P S Cl Ar
sodium magnesium aluminium silicon phosphorus sulfur chlorine argon

23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
caesium barium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Fl Lv
francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium flerovium livermorium
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
lanthanoids La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
actinoids Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium
– 232 231 238 – – – – – – – – – – –
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.)
Back to contents page

Cambridge IGCSE Chemistry 0620 syllabus for 2020 and 2021. Appendix
Safety in the laboratory

Responsibility for safety matters rests with Centres. Further information can be found from the following UK
associations, publications and regulations.
Associations
CLEAPSS is an advisory service providing support in practical science and technology.
www.cleapss.org.uk
Publications
CLEAPSS Laboratory Handbook, updated 2009 (available to CLEAPSS members only)
CLEAPSS Hazcards, 2007 update of 1995 edition (available to CLEAPSS members only)
UK regulations
Control of Substances Hazardous to Health Regulations (COSHH) 2002 and subsequent amendment in 2004
www.legislation.gov.uk/uksi/2002/2677/contents/made
www.legislation.gov.uk/uksi/2004/3386/contents/made
a brief guide may be found at

www.hse.gov.uk/pubns/indg136.pdf
Mathematical requirements
Calculators may be used in all parts of the examination.
Candidates should be able to:

•• add, subtract, multiply and divide
•• use averages, decimals, fractions, percentages, ratios and reciprocals
•• use standard notation, including both positive and negative indices
•• understand significant figures and use them appropriately
•• recognise and use direct and inverse proportion
•• use positive, whole number indices in algebraic expressions
•• draw charts and graphs from given data
•• interpret charts and graphs
•• determine the gradient and intercept of a graph
•• select suitable scales and axes for graphs
•• make approximate evaluations of numerical expressions
•• understand the meaning of angle, curve, circle, radius, diameter, circumference, square, rectangle and diagonal
•• solve equations of the form x = y + z and x = yz for any one term when the other two are known.

Presentation of data
The solidus (/) is to be used for separating the quantity and the unit in tables, graphs and charts, e.g. time / s for
time in seconds.
(a) Tables
•• Each column of a table should be headed with the physical quantity and the appropriate unit, e.g. time / s.
•• The column headings of the table can then be directly transferred to the axes of a constructed graph.
(b) Graphs
•• Unless instructed otherwise, the independent variable should be plotted on the x-axis (horizontal axis) and
the dependent variable plotted on the y-axis (vertical axis).
•• Each axis should be labelled with the physical quantity and the appropriate unit, e.g. time / s.
•• Unless instructed otherwise, the scales for the axes should allow more than half of the graph grid to be
used in both directions, and be based on sensible ratios, e.g. 2 cm on the graph grid representing 1, 2 or 5
units of the variable.
•• The graph is the whole diagrammatic presentation, including the best-fit line when appropriate. It may
have one or more sets of data plotted on it.
•• Points on the graph should be clearly marked as crosses (×) or encircled dots ().
•• Large ‘dots’ are penalised. Each data point should be plotted to an accuracy of better than one half of each
of the smallest squares on the grid.
•• A best-fit line (trend line) should be a single, thin, smooth straight-line or curve. The line does not need to
coincide exactly with any of the points; where there is scatter evident in the data, Examiners would expect
a roughly even distribution of points either side of the line over its entire length. Points that are clearly
anomalous should be ignored when drawing the best-fit line.
•• The gradient of a straight line should be taken using a triangle whose hypotenuse extends over at least half
of the length of the best-fit line, and this triangle should be marked on the graph.
(c) Numerical results
•• Data should be recorded so as to reflect the precision of the measuring instrument.
•• The number of significant figures given for calculated quantities should be appropriate to the least number
of significant figures in the raw data used.
(d) Pie charts
•• These should be drawn with the sectors in rank order, largest first, beginning at ‘noon’ and proceeding
clockwise. Pie charts should preferably contain no more than six sectors.
(e) Bar charts
•• These should be drawn when one of the variables is not numerical. They should be made up of narrow
blocks of equal width that do not touch.
(f) Histograms
•• These are drawn when plotting frequency graphs with continuous data. The blocks should be drawn in
order of increasing or decreasing magnitude and they should touch.

ICT opportunities
In order to play a full part in modern society, candidates need to be confident and effective users of ICT. This
syllabus provides candidates with a wide range of opportunities to use ICT in their study of chemistry.
Opportunities for ICT include:

•• gathering information from the internet, DVDs and CD-ROMs
•• gathering data using sensors linked to data-loggers or directly to computers
•• using spreadsheets and other software to process data
•• using animations and simulations to visualise scientific ideas
•• using software to present ideas and information on paper and on screen.
Conventions (e.g. signs, symbols, terminology and nomenclature)

Syllabuses and question papers conform with generally accepted international practice. In particular, the following
document, produced by the Association for Science Education (ASE), should be used as a guideline.
•• Signs, Symbols and Systematics: The ASE Companion to 16–19 Science (2000).
Litre/dm3
To avoid any confusion concerning the symbol for litre, dm3 will be used in place of l or litre.
Decimal markers
In accordance with current ASE convention, decimal markers in examination papers will be a single dot on the line.
Candidates are expected to follow this convention in their answers.
Numbers
Numbers from 1000 to 9999 will be printed without commas or spaces. Numbers greater than or equal to 10 000
will be printed without commas. A space will be left between each group of three whole numbers, e.g. 4 256 789.

6 What else you need to know
This section is an overview of other information you need to know about this syllabus. It will help to share the
administrative information with your exams officer so they know when you will need their support. Find more
information about our administrative processes at www.cambridgeinternational.org/examsofficers
Before you start

Previous study
We recommend that learners starting this course should have studied a chemistry curriculum such as the
Cambridge Lower Secondary programme or equivalent national educational framework such as the Key Stage 3
programme of study within the National Curriculum for England.
Guided learning hours

We design Cambridge IGCSE syllabuses based on learners having about 130 guided learning hours for each subject
during the course but this is for guidance only. The number of hours a learner needs to achieve the qualification
may vary according to local practice and their previous experience of the subject.
Availability and timetables

You can enter candidates in the June and November exam series. If your school is in India, you can enter your
candidates in the March exam series. You can view the timetable for your administrative zone at
www.cambridgeinternational.org/timetables
Private candidates can enter for this syllabus.
Combining with other syllabuses

Candidates can take this syllabus alongside other Cambridge International syllabuses in a single exam series. The
only exceptions are:
•• Cambridge IGCSE (9–1) Chemistry (0971)
•• Cambridge IGCSE Physical Science (0652)
•• Cambridge IGCSE Combined Science (0653)
•• Cambridge IGCSE Co-ordinated Sciences (Double Award) (0654)
•• Cambridge IGCSE (9–1) Co-ordinated Sciences (Double Award) (0973)
•• Cambridge O Level Combined Science (5129)
•• syllabuses with the same title at the same level.
Cambridge IGCSE, Cambridge IGCSE (9–1) and Cambridge O Level syllabuses are at the same level.

Cambridge IGCSE Chemistry 0620 syllabus for 2020 and 2021. What else you need to know
Group awards: Cambridge ICE

Cambridge ICE (International Certificate of Education) is a group award for Cambridge IGCSE. It allows schools
to offer a broad and balanced curriculum by recognising the achievements of learners who pass examinations in a
range of different subjects.
Learn more about Cambridge ICE at www.cambridgeinternational.org/cambridgeice
Making entries
Exams officers are responsible for submitting entries to Cambridge International. We encourage them to work
closely with you to make sure they enter the right number of candidates for the right combination of syllabus
components. Entry option codes and instructions for submitting entries are in the Cambridge Guide to Making
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Changes to this syllabus for 2020 and 2021

The syllabus has been updated. This is version 1, published September 2017.
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Copyright © UCLES September 2017

Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
*0123456789*
CHEMISTRY 0620/01
Paper 1 Multiple Choice (Core) For Examination from 2016
SPECIMEN PAPER
45 minutes
Additional Materials: Multiple Choice Answer Sheet
Soft clean eraser
Soft pencil (type B or HB is recommended)
READ THESE INSTRUCTIONS FIRST
Write in soft pencil.

Do not use staples, paper clips, glue or correction fluid.
Write your name, Centre number and candidate number on the Answer Sheet in the spaces provided unless
this has been done for you.
DO NOT WRITE IN ANY BARCODES.
There are forty questions on this paper. Answer all questions. For each question there are four possible
answers A, B, C and D.
Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet.
Read the instructions on the Answer Sheet very carefully.
Each correct answer will score one mark. A mark will not be deducted for a wrong answer.
Any rough working should be done in this booklet.
A copy of the Periodic Table is printed on page 18.
Electronic calculators may be used.
The syllabus is accredited for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 18 printed pages.
© UCLES 2014 [Turn over

2
1 The diagrams show the arrangement of particles in three different physical states of substance X.
state 1 state 2 state 3
Which statement about the physical states of substance X is correct?
A Particles in state 1 vibrate about fixed positions.

B State 1 changes to state 2 by diffusion.
C State 2 changes directly to state 3 by condensation.
D The substance in state 3 has a fixed volume.
2 What is always true for a pure substance?
A It always boils at 100 °C.

B It contains only one type of atom.
C It has a sharp melting point.
D It is solid at room temperature.
3 Element Y has a nucleon number of 19 and a proton number of 9.
Which group in the Periodic Table does it belong to?
A I B III C VII D VIII
4 The nucleon number and proton number of the lithium atom are shown by the symbol 73 Li.
What is the correct symbol for the lithium ion in lithium chloride?
6 6 7 7
A 2
Li– B 3
Li+ C 3
Li+ D 3
Li–
5 What is the relative molecular mass, Mr, of HNO3?
A 5 B 31 C 32 D 63
© UCLES 2014 0620/01/SP/16

3
6 The table shows the structure of different atoms and ions.
particle proton nucleon number of number of number of

number number protons neutrons electrons
Mg 12 24 12 W 12
Mg2+ X 24 12 12 10
F 9 19 9 Y 9
F– 9 19 9 10 Z
What are the values of W, X, Y and Z?
W X Y Z
A 10 10 9 9
B 10 12 10 9
C 12 10 9 10
D 12 12 10 10
7 The diagram shows the structure of an atom.
key
+ = proton
+ +
– – n = neutron
n n
– = electron
Which diagram shows the structure of an isotope of this atom?
A B C D
+ + + + + + + + + + +
– – – – – – – –
n n n n n n n n n
© UCLES 2014 0620/01/SP/16 [Turn over

4
8 Which two elements react together to form an ionic compound?
element electronic structure
R 2,4
T 2,8
X 2,8,1
Z 2,8,7
A R and T B T and X C X and Z D Z and R
9 Element X forms an acidic, covalent oxide.
Which row shows how many electrons there could be in the outer shell of an atom of X?
1 2 6 7
A
B
C
D
10 Which diagram does not show the outer shell electrons in the molecule correctly?
A B C D
H H H Cl H C H Cl Cl
11 The chemical formulae of two substances, W and X, are given.
W NaAl Si3O8
X CaAl2Si2O8
Which statements are correct?
1 W and X contain the same amount of oxygen.
2 W contains three times as much silicon as X.
3 X contains twice as much aluminium as W.
A 1 and 2 B 1 and 3 C 2 and 3 D 1, 2 and 3
© UCLES 2014 0620/01/SP/16

5
12 The diagram shows apparatus used in an attempt to electroplate a metal ring with copper.
battery
+ –
bulb
metal ring copper electrode

aqueous copper(II)
sulfate (electrolyte)
The experiment did not work.
Which change is needed in the experiment to make it work?
A Add solid copper(II) sulfate to the electrolyte.

B Increase the temperature of the electrolyte.
C Replace the copper electrode with a carbon electrode.
D Reverse the connections to the battery.
13 Three electrolysis cells are set up. Each cell has inert electrodes.
The electrolytes are listed below.
cell 1 aqueous sodium chloride
cell 2 dilute sulfuric acid
cell 3 molten lead(II) bromide
In which of these cells is a gas formed at both electrodes?
A 1 and 2 B 1 and 3 C 2 only D 3 only

6
14 Which process is not exothermic?
A burning a fossil fuel

B obtaining lime from limestone
C radioactive decay of 235U
D reacting hydrogen with oxygen
15 The apparatus shown can be used to measure the rate of some chemical reactions.
gas syringe
reaction mixture
For which two reactions would this apparatus be suitable?
reaction 1 AgNO3(aq) + HCl(aq) → AgCl(s) + HNO3(aq)
reaction 2 2H2O2(aq) → 2H2O(I) + O2(g)
reaction 3 MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O(I)
reaction 4 ZnCO3(s) + 2HCl(aq) → ZnCl2(aq) + CO2(g) + H2O(I)
A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4
© UCLES 2014 0620/01/SP/16

7
16 A student investigates the rate of reaction between magnesium and excess sulfuric acid.
The volume of hydrogen given off in the reaction is measured over time.
The graph shows the results of two experiments, R and S.
R
volume of S
hydrogen
given off
time
Which change in conditions would cause the difference between R and S?
A A catalyst is added in S.
B The acid is more concentrated in R than in S.
C The magnesium is less finely powdered in R than in S.
D The temperature in R is lower than in S.
17 When pink cobalt(II) chloride crystals are heated they form steam and a blue solid.
When water is added to the blue solid, it turns pink and becomes hot.
Which terms describe the pink cobalt(II) chloride crystals and the reactions?
pink cobalt(II) chloride reactions
A aqueous irreversible
B anhydrous reversible
C hydrated irreversible
D hydrated reversible

8
18 The red colour in some pottery glazes may be formed as a result of the reactions shown.
heat
CuCO3 CuO + CO2
CuO + SnO Cu + SnO2
These equations show that ......1...... is oxidised and ......2...... is reduced.
Which substances correctly complete gaps 1 and 2 in the above sentence?
1 2
A CO2 SnO2
B CuCO3 CuO
C CuO SnO
D SnO CuO
19 Carbon dioxide gas reacts with aqueous sodium hydroxide.
Which type of reaction takes place?
A decomposition
B fermentation
C neutralisation
D oxidation
20 An aqueous solution of the organic compound methylamine has a pH greater than 7.
Which statement about methylamine is correct?
A It neutralises an aqueous solution of sodium hydroxide.

B It reacts with copper(II) carbonate to give carbon dioxide.
C It reacts with hydrochloric acid to form a salt.
D It turns blue litmus red.
21 A solution contains barium ions and silver ions and one type of anion.
What could the anion be?
A chloride only
B nitrate only
C sulfate only
D chloride or nitrate or sulfate
© UCLES 2014 0620/01/SP/16

9
22 A mixture containing two anions was tested and the results are shown below.
test result
dilute nitric acid added effervescence of a gas which

turned limewater milky
dilute nitric acid added, followed yellow precipitate formed

by aqueous silver nitrate
Which anions were present?
A carbonate and chloride

B carbonate and iodide
C sulfate and chloride
D sulfate and iodide
23 Astatine is an element in Group VII of the Periodic Table. It has only ever been produced in very
small amounts.
What are the likely properties of astatine?
reaction with aqueous

colour state
potassium iodide
A black solid no reaction

B dark brown gas brown colour
C green solid no reaction
D yellow liquid brown colour

10
24 The diagram shows the positions of elements L, M, Q, R and T in the Periodic Table.
These letters are not the chemical symbols of the elements.
R T
M Q
Which statement about the properties of these elements is correct?
A L reacts more vigorously with water than does M.

B L, M and Q are all metals.
C T exists as diatomic molecules.
D T is more reactive than R.
25 The table compares the properties of Group I elements with those of transition elements.
Which entry in the table is correct?
property Group I elements transition elements
A catalytic activity low high

B density high low
C electrical conductivity low low
D melting point high low
26 X is a monatomic gas.
gas X
Which statement about gas X is correct?
A X burns in air.
B X is coloured.
C X is unreactive.
D X will displace iodine from potassium iodide.
© UCLES 2014 0620/01/SP/16

11
27 Aluminium is an important metal with many uses.
Some of its properties are listed.
1 It is a good conductor of heat.
2 It has a low density.
3 It has an oxide layer that prevents corrosion.
Which set of properties help to explain the use of aluminium for cooking and storing food?
A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3
28 Which diagram could represent the structure of an alloy?
A B
– + – +
+ – + –
– + – +
C D

12
29 The table shows the results of adding three metals, P, Q and R, to dilute hydrochloric acid and to
water.
metal dilute hydrochloric acid water
P hydrogen produced hydrogen produced
Q no reaction no reaction
R hydrogen produced no reaction
What is the order of reactivity of the metals?
most reactive least reactive
A P R Q
B P Q R
C R Q P
D R P Q
30 The table gives the composition of the atmosphere of four newly discovered planets.
planet composition of atmosphere
W argon, carbon dioxide and oxygen
X argon, nitrogen and oxygen
Y argon, carbon dioxide and methane
Z methane, nitrogen and oxygen
On which planets is the greenhouse effect likely to occur?
A W only
B W, X and Z
C W and Y only
D W, Y and Z
© UCLES 2014 0620/01/SP/16

13
31 Compound X is heated with carbon using the apparatus shown.
compound X and reaction tube

carbon
heat
limewater
A brown solid is formed in the reaction tube and the limewater turns cloudy.
What is compound X?
A calcium oxide
B copper(II) oxide
C magnesium oxide
D sodium oxide
32 The diagram shows some reactions of substance Y.
heat with an
ammonium compound
ammonia
substance Y
a salt
heat with
dilute acid
Which type of substance is Y?
A an alcohol
B a base
C a catalyst
D a metal

14
33 A test-tube containing damp iron wool is inverted in water.
After three days, the water level inside the test-tube has risen.
damp iron wool
water
Which statement explains this rise?
A Iron oxide has been formed.

B Iron wool has been reduced.
C Oxygen has been formed.
D The temperature of the water has risen.
34 Greenhouse gases may contribute to climate change.
Two of these gases are emitted into the atmosphere as a result of processes within animals.
Gas …..1….. is produced by process …..3….. .
Gas …..2….. is produced by process …..4….. .
Which row correctly complete gaps 1, 2, 3 and 4?
1 2 3 4
A CO C2H6 digestion respiration

B CO C2H6 respiration digestion
C CO2 CH4 digestion respiration
D CO2 CH4 respiration digestion
© UCLES 2014 0620/01/SP/16

15
35 To grow rose plants, a fertiliser containing nitrogen, phosphorus and potassium is often used.
For the best rose flowers, the fertiliser should contain a high proportion of potassium.
Which fertiliser is best for producing rose flowers?
proportion by mass
fertiliser
N P K
A 9 0 25
B 13 13 20
C 29 5 0
D 29 15 5
36 Air containing an acidic impurity was neutralised by passing it through a column containing
substance X.
substance X
acidic air neutralised air
What is substance X?
A calcium oxide
B sand
C sodium chloride
D concentrated sulfuric acid

16
37 In an oil refinery, petroleum is separated into useful fractions.
The diagram shows some of these fractions.
refinery gases
gasoline
X
pre-heat diesel oil
400 °C Y
Z
What are fractions X, Y and Z?
X Y Z
A fuel oil bitumen paraffin (kerosene)

B fuel oil paraffin (kerosene) bitumen
C paraffin (kerosene) bitumen fuel oil
D paraffin (kerosene) fuel oil bitumen
38 The structures of three compounds are shown.
H H H H H H H H H H
C C H C C C C H H C C C C C C H
H H H H H H H H H H
Why do these substances all belong to the same homologous series?
A They all contain an even number of carbon atoms.

B They all contain the same functional group.
C They are all hydrocarbons.
D They are all saturated.
39 Which bond is not in a molecule of ethanoic acid?
A C–O B C=O C C=C D O–H
© UCLES 2014 0620/01/SP/16

17
40 Which structure is incorrect?
A B C D
H H H O H H H H
H C C H H C C O H H C C H H C C O H
H H H H H H H
© UCLES 2014 0620/01/SP/16

18
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2014 0620/01/SP/16

CHEMISTRY 0620/01
Paper 1 Multiple Choice For Examination from 2016
SPECIMEN MARK SCHEME
45 minutes
MAXIMUM MARK: 40

2
Question Question
Key Key
Number Number
1 D 21 B
2 C 22 B
3 C 23 A
4 C 24 B
5 D 25 A
6 D 26 C
7 A 27 D
8 C 28 D
9 C 29 A
10 D 30 D
11 B 31 B
12 D 32 B
13 A 33 A
14 B 34 D
15 C 35 B
16 B 36 A
17 D 37 D
18 D 38 B
19 C 39 C
20 C 40 C
© UCLES 2014 0620/01/SM/16

*0123456789*
CHEMISTRY 0620/02
Paper 2 Multiple Choice (Extended) For Examination from 2016
SPECIMEN PAPER
45 minutes
Soft clean eraser


2
1 Amino acids are colourless and can be separated and identified by chromatography.
glass cover
beaker
chromatography
paper solvent
What additional apparatus is required to identify the amino acids present in a mixture?
A a locating agent
B a ruler
C a ruler and a locating agent
D neither a ruler or a locating agent
2 The diagram shows the diffusion of hydrogen chloride and ammonia in a glass tube.
The gases are given off by the solutions at each end of the tube.
When hydrogen chloride and ammonia mix they produce a white solid, ammonium chloride.
Which line shows where the white solid is formed?
A B C D
cotton wool soaked in cotton wool soaked in

concentrated ammonia concentrated
solution hydrochloric acid
© UCLES 2014 0620/02/SP/16

3
key
+ = proton
+ +
– – n = neutron
n n
– = electron
A B C D
+ + + + + + + + + + +
– – – – – – – –
n n n n n n n n n
proton nucleon number of number of number of

particle
Mg 12 24 12 W 12
Mg2+ X 24 12 12 10
F 9 19 9 Y 9
F– 9 19 9 10 Z
W X Y Z
A 10 10 9 9
B 10 12 10 9
C 12 10 9 10
D 12 12 10 10

4
5 Iron is a metal. The structure of iron is described as a lattice of positive ions in a sea of electrons.
Which of the following statements about iron are correct?
1 iron conducts electricity because the electrons are free to move
2 iron has a high melting point due to the strong covalent bonds
3 iron is an alloy
4 iron is malleable because the layers of atoms can slide over one another
A 1 only
B 1 and 3
C 1 and 4
D 2, 3 and 4
R 2,4
T 2,8
X 2,8,1
Z 2,8,7
7 Ethene is an unsaturated hydrocarbon.
H H
C C
H H
Which description of the bonding in ethene is correct?
A All atoms in the molecule have a share of eight electrons.

B Each carbon atom shares two of its electrons with hydrogen atoms and two of its electrons
with a carbon atom.
C Each carbon atom shares two of its electrons with hydrogen atoms and one of its electrons
with a carbon atom.
D The two carbon atoms share a total of six electrons with other atoms.
8 What is the relative molecular mass, Mr, of butanol?
A 15 B 37 C 74 D 148
© UCLES 2014 0620/02/SP/16

5
W NaAl Si3O8
X CaAl2Si2O8
10 What is the concentration of a solution containing 1.0 g of sodium hydroxide in 250 cm3 of
solution?
A 0.025 mol / dm3

B 0.10 mol / dm3
C 0.25 mol / dm3
D 1.0 mol / dm3
11 Four students prepared hydrated copper(II) sulfate by adding an excess of dilute sulfuric acid to
copper(II) oxide.
Each student used a different mass of copper(II) oxide.
dilute sulfuric acid

CuO CuSO4.5H2O
Mr = 80 Mr = 250
After the copper(II) sulfate had crystallised the students dried and weighed the crystals.
Which student produced the highest percentage yield of hydrated copper(II) sulfate?
mass of copper(II) mass of crystals

oxide used / g produced / g
A 4.0 11.5
B 8.0 23.5
C 12.0 35.0
D 16.0 46.5

6
12 20 cm3 of ethyne, C2H2, are reacted with 500 cm3 of oxygen.
The equation for the reaction is
2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(l)
What is the total volume of gas remaining at the end of the reaction?
(all volumes are measured at room temperature and pressure)
A 400 cm3
B 450 cm3
C 490 cm3
D 520 cm3
13 Different metals were tested using the apparatus shown.
V
metal 1 metal 2
Which pair of metals would produce the largest voltage?
A copper and silver

B magnesium and silver
C magnesium and zinc
D zinc and copper
© UCLES 2014 0620/02/SP/16

7
15 The statements refer to the electrolysis of concentrated copper(II) chloride solution.
1 Electrons are transferred from the cathode to the copper(II) ions.
2 Electrons move around the circuit from the cathode to the anode.
3 Chloride ions are attracted to the anode.
4 Hydroxide ions transfer electrons to the cathode.
Which statements about the electrolysis of concentrated copper(II) chloride are correct?
A 1 and 3
B 1 and 4
C 2 and 3
D 2 and 4
16 Water can be used to produce hydrogen gas.
2H2O → 2H2 + O2
Which row describes bond breaking in the reactant?
A endothermic heat absorbed

B endothermic heat released
C exothermic heat absorbed
D exothermic heat released
17 Dinitrogen tetroxide, N2O4, breaks down into nitrogen dioxide, NO2.
N2O4(g) ⇌ 2NO2(g)
The reaction is reversible and endothermic.
Which conditions will give the largest yield of nitrogen dioxide, NO2?
temperature pressure
A high high
B high low
C low high
D low low

8
gas syringe
reaction mixture
R
volume of S
hydrogen
given off
time
© UCLES 2014 0620/02/SP/16

9
20 Which of these reactions shows only reduction?
A Cu2+ + 2e– Cu
B Fe2O3 + 3CO 2Fe + 3CO2
C HCl + NaOH NaCl + H2O
D Mg + ZnSO4 Zn + MgSO4
heat
CuCO3 CuO + CO2
CuO + SnO Cu + SnO2
1 2
A CO2 SnO2
B CuCO3 CuO
C CuO SnO
D SnO CuO
22 Acids are compounds which donate protons (hydrogen ions).
NH3(aq) + H2O(l) → NH4+(aq) + OH–(aq)
Which compound in this equation is behaving as an acid?
A ammonia
B ammonium hydroxide
C none of them
D water

10
23 The reactions of four different oxides W, X, Y and Z are shown.
W reacts with hydrochloric acid but not sodium hydroxide.
X reacts with both hydrochloric acid and sodium hydroxide.
Y does not react with either hydrochloric acid or sodium hydroxide.
Z reacts with sodium hydroxide but not hydrochloric acid.
Which row shows the correct types of oxide?
acidic basic amphoteric neutral
A W Z X Y
B X Y W Z
C Z X Y W
D Z W X Y
A chloride only
B nitrate only
C sulfate only
test result



© UCLES 2014 0620/02/SP/16

11
26 Part of the Periodic Table is shown.
The letters are not the chemical symbols of the elements.
W X
Z Y
Which statement about the elements is not correct.
A W has two electrons in the outermost shell.

B Y is in Group IV of the Periodic Table.
C X and Y bond covalently to form a molecule XY4.
D Z has more metallic character than Y.
small amounts.

colour state
potassium iodide

12
water.
A P R Q
B P Q R
C R Q P
D R P Q

carbon
heat
limewater
What is compound X?
A calcium oxide
B copper(II) oxide
C magnesium oxide
D sodium oxide
© UCLES 2014 0620/02/SP/16

13
30 Zinc is extracted from zinc blende. Zinc blende is an ore of zinc and consists mainly of zinc
sulfide.
One of the steps in the process involves zinc sulfide reacting with oxygen from the air.
What is the equation for this reaction?
A 2ZnS + 3O2 → 2ZnO + 2SO2
B 2ZnS + O2 → 2Zn + SO2
C 2ZnS + O2 → 2ZnO + S
D ZnS + 2O2 → ZnSO4
31 The diagram shows the carbon cycle.
carbon dioxide in
atmosphere
gradual production of
fossil fuels
coal, oil
and
natural gas
Which process is shown by the arrow marked X?
A combustion
B photosynthesis
C respiration
D transpiration

14
32 A catalytic converter removes harmful gases from motor car exhausts.
Which reaction does not take place in a catalytic converter?
A 2CO + O2 → 2CO2
B N2 + 2CO2 → 2NO + 2CO
C 2NO2 → N2 + 2O2
D 2NO2 + 4CO → N2 + 4CO2
heat with an
ammonium compound
ammonia
substance Y
a salt
heat with
dilute acid
A an alcohol
B a base
C a catalyst
D a metal
© UCLES 2014 0620/02/SP/16

15
34 Which row shows the conditions for the manufacture of sulfuric acid?
pressure / atm temperature / °C catalyst
A 2 450 vanadium(V) oxide

B 2 250 iron
C 200 450 iron
D 200 250 vanadium(V) oxide
substance X.
substance X
A calcium oxide
B sand
C sodium chloride

16
refinery gases
gasoline
X
pre-heat diesel oil
400 °C Y
Z
X Y Z

37 Which reaction does not take place in the dark?
A CH4 + 2O2 → CO2 + 2H2O

B CH4 + Cl2 → CH3Cl + HCl
C C2H4 + H2O → C2H5OH
D C2H4 + H2 → C2H6
38 Ethane and ethene are both hydrocarbons.
Ethane reacts with chlorine and ethene reacts with bromine.
Which row describes the type of reaction that ethane and ethene undergo?
ethane ethene
A addition addition
B addition substitution
C substitution substitution
D substitution addition
© UCLES 2014 0620/02/SP/16

17
39 Esters are made by reacting an alcohol with a carboxylic acid.
Which acid and alcohol react together to form the following ester?
O
CH3CH2 C
OCH3
A propanoic acid and ethanol

B propanoic acid and methanol
C ethanoic acid and ethanol
D ethanoic acid and methanol
40 Which structure represents a polymer?
H O H O
C N C N C N C
H O
© UCLES 2014 0620/02/SP/16

18
© UCLES 2014 0620/02/SP/16

CHEMISTRY 0620/02
Paper 2 Multiple Choice For Examination from 2016
45 minutes
MAXIMUM MARK: 40

2
Question Question
Key Key
Number Number
1 C 21 D
2 D 22 D
3 A 23 D
4 D 24 B
5 C 25 B
6 C 26 C
7 B 27 A
8 C 28 A
9 B 29 B
10 B 30 A
11 B 31 C
12 C 32 B
13 B 33 B
14 A 34 A
15 A 35 A
16 A 36 D
17 B 37 B
18 C 38 D
19 B 39 B
20 A 40 C
© UCLES 2014 0620/02/SM/16

*0123456789*
CHEMISTRY 0620/03
Paper 3 Theory (Core) For Examination from 2016
SPECIMEN PAPER
1 hour 15 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
Write your Centre number, candidate number and name on all the work you hand in.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Answer all questions.

You may lose marks if you do not show your working or if you do not use appropriate units.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
This document consists of 15 printed pages and 1 blank page.

2
1 The structures of diamond and chlorine are shown below.
diamond chlorine
= carbon atom = chlorine atom
(a) Describe the structure of these two substances.

Use the list of words to help you.
covalent diatomic giant macromolecule molecule structure
diamond
chlorine
[4]
(b) The structure of a compound containing carbon and chlorine is shown below.
Cl Cl
Cl Cl
C
Cl C C Cl
Cl C C Cl
C
Cl Cl
Cl Cl
What is the molecular formula of this compound?
[1]
© UCLES 2014 0620/03/SP/16

3
(c) Chlorine is a halogen.
(i) State the colour of chlorine.
[1]
The table shows some properties of the halogens.
density in liquid
element boiling point / °C colour
state / g per cm3
fluorine –188 1.51 yellow
chlorine –35 1.56
bromine –7 red-brown
iodine +114 4.93 grey-black
Use the information in the table to answer the following questions.
(ii) Predict the density of liquid bromine.
[1]
(iii) Describe the trend in boiling point of the halogens down the group.
[1]
(d) (i) Complete the word equation for the reaction of bromine with aqueous potassium iodide.
bromine + potassium iodide → …………………... + …………………...
…………………... [2]
(ii) Suggest why bromine does not react with aqueous potassium chloride.
[1]
(e) Potassium chloride is an ionic substance but iodine is a molecular substance.

How do most ionic and molecular substances differ in their
solubility in water?
electrical conductivity?
[2]
[Total: 13]

4
2 Bromine is an element in Group VII of the Periodic Table.
(a) State the formula for a molecule of bromine.
[1]
(b) A teacher placed a small amount of liquid bromine in the bottom of a sealed gas jar of air.
After two minutes red-brown fumes were seen just above the liquid surface. After one hour
the red-brown colour had spread completely throughout the gas jar.
air
liquid
bromine
start after 2 minutes after 1 hour
Use the kinetic particle model of matter to explain these observations.
[3]
[Total: 4]
© UCLES 2014 0620/03/SP/16

5
3 The structures of some substances containing nitrogen are shown below.
A B C
K+ NO3– K+
N N
H H NO3– K+ NO3– I I
H I
K+ NO3– K+
D E
N
N N O O
Answer the following questions by choosing from the structures A, B, C, D or E.

You can use each structure once, more than once or not at all.
Which structure represents
(a) an acidic oxide, [1]
(b) an ionic structure, [1]
(c) a gas which turns damp red litmus paper blue, [1]
(d) a compound which is formed under conditions [1]

of high temperature and pressure in car engines,
(e) a molecule containing halogen atoms, [1]
(f) a salt? [1]
[Total: 6]

6
4 The diagram shows a rotary lime kiln used to make lime from limestone.
Limestone is fed in at the top of the kiln and lime comes out at the bottom.
kiln moves air out

round limestone
hot air
lime
(a) State the chemical name for lime?
[1]
(b) State the name of the type of chemical reaction that takes place in the kiln.
[1]
(c) Suggest why the air coming out of the kiln has a greater percentage of carbon dioxide than
the air entering the kiln.
[1]
(d) State one use for lime.
[1]
(e) A student compared the rates of reaction of three metal carbonates.

She measured the volume of gas released using the apparatus shown.
gas syringe
metal carbonate
heat
State one thing that must be kept constant if the rates of the three reactions are to be
compared in a fair way.
[1]
© UCLES 2014 0620/03/SP/16

7
(f) The graph shows the volume of carbon dioxide released when the three metal carbonates
were heated.
50
calcium
40 carbonate
30 strontium
volume of carbonate
carbon dioxide
/ cm3
20
barium
carbonate
10
0
0 2 4 6 8 10 12
time / minutes
(i) Which carbonate produced carbon dioxide at the highest rate?
[1]
(ii) What volume of carbon dioxide was produced by strontium carbonate in twelve minutes?
[1]
(iii) How do the rates of the reactions of these three metal carbonates relate to the position
of calcium, strontium and barium in the Periodic Table?
[2]
(g) Describe how hydrochloric acid and limewater can be used to show that carbonate ions are
present in calcium carbonate.
[3]
[Total: 12]

8
5 Iron is a transition element.
(a) State three properties of transition elements which are not shown by the Group I elements.
1.
2.
3. [3]
(b) The symbols for two isotopes of iron are shown below.
54 57
26
Fe 26
Fe
(i) How do these two isotopes differ in their atomic structure?
[1]
57
(ii) Determine the number of neutrons present in one atom of the isotope 26
Fe.
[1]
(iii) Determine the number of electrons in one Fe3+ ion?
[1]
(c) Pure iron rusts very easily.
Describe and explain one method of preventing rusting.
method
explain why this method works
[2]
(d) Iron can be recycled.
Explain two advantages of recycling metals.
[2]
© UCLES 2014 0620/03/SP/16

9
(e) In the blast furnace, iron(III) oxide reacts with carbon monoxide.
Fe2O3 + 3CO → 2Fe + 3CO2
Which substance gets reduced in this reaction?

Explain your answer.
substance
explanation
[2]
(f) (i) Carbon monoxide is a pollutant gas produced in motor car engines.
State why carbon monoxide is formed.
[1]
(ii) State one harmful effect of carbon monoxide.
[1]
[Total: 14]

10
6 Concentrated hydrochloric acid can be electrolysed using the apparatus shown.
concentrated
hydrochloric acid
positive electrode negative electrode

+ –
(a) Define the term electrolysis?
[1]
(b) What is the name given to the positive electrode?

Put a ring around the correct answer.
anion anode cathode cation electrolyte

[1]
(c) State the name of the gas given off at the negative electrode.
[1]
(d) Complete the following sentence about electrolysis using words from the list.
inert magnesium platinum reactive solid
Electrodes made of graphite or …………………… are generally used in electrolysis
because they are …………………… . [2]
© UCLES 2014 0620/03/SP/16

11
(e) When concentrated hydrochloric acid is electrolysed, chlorine is released.
(i) Draw the shells and the electronic structure in an atom of chlorine.
[1]
(ii) Draw the electronic structure of a chlorine molecule.

Show only the outer electron shells.
[2]
(iii) Describe a test for chlorine.
test
result [2]
(f) Hydrochloric acid reacts with the base calcium hydroxide.
(i) Complete the word equation for this reaction.
hydrochloric acid + calcium hydroxide → …………………… + ……………………
…………………… [2]
(ii) Hydrochloric acid also reacts with zinc.

Complete the symbol equation for this reaction.
Zn + ........HCl → ZnCl2 + ........

[2]
[Total: 14]

12
7 The pie chart shows the composition of air.
nitrogen
oxygen
other gases
(a) (i) What is the percentage of nitrogen in the air?
[1]
(ii) Apart from nitrogen and oxygen, state the names of two gases present in unpolluted air.
and [2]
(b) The percentage of oxygen in air can be found using the apparatus shown below.
air copper wire air
gas syringe
heat
Air is passed backwards and forwards over the heated copper using the syringes. The
copper reacts with oxygen in the air.
copper + oxygen → copper(II) oxide
As the experiment proceeds, suggest what happens to
(i) the total volume of air in the gas syringes,
[1]
(ii) the mass of the wire in the tube.
[1]
(c) State one use of copper.
[1]
[Total: 6]
© UCLES 2014 0620/03/SP/16

13
8 Ethene, C2H4, is manufactured by cracking petroleum fractions.
(a) (i) What do you understand by the term fraction?
[1]
(ii) Complete the symbol equation for the manufacture of ethene from dodecane, C12H26.
C12H26 → C2H4 + …………

[1]
(b) Two fractions obtained from the distillation of petroleum are refinery gas and gasoline.
State one use of each of these fractions.
refinery gas
gasoline [2]
(c) Ethene is an unsaturated hydrocarbon.

What do you understand by the following terms?
unsaturated
hydrocarbon [2]
(d) Ethene is used to make ethanol.
(i) Which of these reactions is used to make ethanol from ethene?

Tick one box.
catalytic addition of steam
fermentation
oxidation using oxygen
reduction using hydrogen

[1]

14
(ii) Draw the structure of ethanol, showing all atoms and bonds.
[2]
(e) Ethene is used to make poly(ethene).

Complete the following sentences about this reaction.
Use words from the list below.
additions carbohydrates catalysts monomers polymers
The ethene molecules which join to form poly(ethene) are the .
The poly(ethene) molecules formed are . [2]
[Total: 11]
© UCLES 2014 0620/03/SP/16

15
BLANK PAGE
© UCLES 2014 0620/03/SP/16

16
© UCLES 2014 0620/03/SP/16

CHEMISTRY 0620/03
Paper 3 Theory (Core) For Examination from 2016
1 hour 15 minutes
MAXIMUM MARK: 80

2
mark scheme abbreviations
; separates marking points
/ alternative responses for the same marking point
not do not allow
allow accept the response
ecf error carried forward
avp any valid point
ora or reverse argument
owtte or words to that effect
underline actual word given must be used by candidate (grammatical variants excepted)
() the word / phrase in brackets is not required but sets the context
max indicates the maximum number of marks
Any [number] from: accept the [number] of valid responses
note: additional marking guidance
© UCLES 2014 0620/03/SM/16

3
1 (a) diamond:
covalent;
giant structure / macromolecule;
chlorine: any two of:
molecule;
covalent;
diatomic; [4]
(b) C6Cl12 [1]
(c) (i) green / yellow-green / light green [1]
(ii) value between 2.5–4(.0) (g per dm3) (actual = 3.12) [1]
(iii) increases [1]
(d) (i) potassium bromide [1]

not: potassium bromine
iodine [1]
not: iodide
(ii) chlorine is more reactive than bromine / ora [1]

not: chloride is more reactive than bromide
(e) solubility in water:

ionic compounds are soluble and molecular compounds are not soluble [1]
note: both needed for mark
electrical conductivity:
ionic compounds conduct electricity when molten / in (aqueous) solution
and molecular compounds do not [1]
2 (a) Br2 [1]
(b) Any three of: [3]

• bromine evaporates / liquid evaporates;
• more energetic particles change from liquid to vapour or gas;
• diffusion;
• random movement of particles / particles move everywhere / air and bromine particles
are moving;
• (bromine and air) particles get mixed up / collision of bromine and air particles;
allow: molecules in place of particles
© UCLES 2014 0620/03/SM/16 [Turn over

4
3 (a) E / nitrogen (di)oxide / NO2 [1]
(b) B / potassium nitrate / KNO3 [1]
(c) A / ammonia / NH3 [1]
(d) E / nitrogen (di)oxide / NO2 [1]
(e) C / NI3 / nitrogen (tri)iodide [1]
(f) B / potassium nitrate / KNO3 [1]
4 (a) calcium oxide [1]

allow: CaO
(b) thermal decomposition [1]
(c) carbon dioxide has been removed from the limestone / it comes from the limestone / carbon
dioxide is a product [1]
(d) neutralising acidic soils / treating acidic lakes / flue gas desulfurisation
allow: any suitable use [1]
(e) temperature of Bunsen / distance of Bunsen from the tube / mass of carbonate used / owtte
[1]
(f) (i) calcium carbonate [1]
(ii) 27 (cm3) [1]
(iii) calcium faster than strontium which is faster than barium / idea of
trend down the group; [1]
correct trend, i.e. less rapid reaction the further down the group / ora; [1]
(g) add acid to carbonate; [1]

bubble gas or carbon dioxide (evolved) through limewater / test gas or carbon
dioxide with limewater; [1]
limewater goes milky or cloudy; [1]
© UCLES 2014 0620/03/SM/16

5
5 (a) Any three of:

high melting / boiling point;
high density;
form coloured compounds or have coloured ions;
form ions of more than one charge / variable valency / variable oxidation state;
allow: form complex ions; hard / hardness; catalysts; [3]
(b) (i) different number of neutrons / different nucleon number [1]
(ii) 31 [1]
(iii) 23 [1]
(c) suitable method, e.g. coating with paint / zinc / unreactive metal / plastic / oil / grease /
galvanising / sacrificial protection; [1]
suitable reason, e.g. stops air / water reaching surface; [1]
note: reason must be consequential to the method chosen
(d) Any two of:

recycling promotes sustainable development / owtte;
uses less energy than extraction;
preserves limited natural resources;
correct reference to cost;
reference to landfill; [2]
(e) Fe2O3 / iron oxide; [1]

it loses oxygen / gains electrons / iron decreases oxidation number; [1]
(f) (i) incomplete combustion / insufficient or limited or not enough oxygen [1]
(ii) toxic / suffocates you / stops red blood cells carrying oxygen / binds with hemoglobin in
place of oxygen [1]
6 (a) break down (of substance / electrolyte) by electricity / splitting up of substance by electricity /
decomposition by electricity [1]
allow: current / voltage for electricity
(b) anode [1]
(c) hydrogen [1]

allow: H2
(d) platinum; [1]

inert; [1]

6
(e) (i) 2,8,7 as shown in an electron shell diagram [1]
(ii) pair of electrons between two chlorine atoms; [1]

rest of electrons correct; [1]
(iii) (damp) litmus (paper) / Universal indicator (paper); [1]

allow: indicator paper / pH paper
bleaches / goes white / goes red then bleaches; [1]
(f) (i) calcium chloride + water (1 mark each) [2]

not: calcium chlorine
(ii) 2 on left; [1]

H2 on right; not: 2H [1]
7 (a) (i) 78 (%) [1]

allow: 78–80
(ii) Any two of: [2]

carbon dioxide; argon; neon; xenon; helium; radon; water;
not: hydrogen
(b) (i) decreases / gets less / gets lower / gets used up [1]
(ii) increases / gets more / greater [1]
(c) any suitable use e.g. electrical conductor / electrical wiring / saucepans [1]
8 (a) (i) (group of) molecules with similar boiling points / (group of) molecules with similar relative
molecular masses / molecules with limited range of boiling points / molecules with limited
range of molecular masses / molecules coming off at the same place in the fractionation
column / owtte [1]
(ii) C10H22
allow: reasonable mixtures, e.g. C7H16 + C3H6 [1]
(b) refinery gas: (fuel) for heating / (fuel) for cars / (fuel) for cooking; [1]
gasoline: (fuel) for cars / mowers etc.; [1]
(c) unsaturated: contains double bonds / contains C=C bonds; [1]

hydrocarbon: containing carbon and hydrogen only; [1]
(d) (i) 1st box down ticked (catalytic addition of steam) [1]
(ii) correct structure of ethanol; [1]

bond between O-H; [1]
(e) monomers; [1]

polymers; [1]
© UCLES 2014 0620/03/SM/16

*0123456789*
CHEMISTRY 0620/04
Paper 4 Theory (Extended) For Examination from 2016
SPECIMEN PAPER
1 hour 15 minutes

This document consists of 18 printed pages and 2 blank pages.

2
1 The following table gives information about six substances.
melting point boiling point electrical conductivity electrical conductivity

substance
/ °C / °C as a solid as a liquid
A 839 1484 good good
B –188 –42 poor poor
C 776 1497 poor good
D –117 78 poor poor
E 1607 2227 poor poor
F –5 102 poor good
(a) Which substance could be a metal?
[1]
(b) State all the substances that are liquid at room temperature?
[1]
(c) Which substance could have a macromolecular structure similar to that of silicon(IV) oxide?
[1]
(d) Which substance could be propane?
[1]
(e) Which substance could be sodium chloride?
[1]
[Total: 5]
© UCLES 2014 0620/04/SP/16

3
2 The table gives the composition of three particles.
number of number of number of

particle
protons electrons neutrons
A 15 15 16
B 15 18 16
C 15 15 17
(a) What is the evidence in the table for each of the following?
(i) Particle A is an atom.
[1]
(ii) A, B and C are all particles of the same element.
[1]
(iii) Particles A and C are isotopes of the same element.
[2]
(b) (i) What is the electronic structure of particle A?
[1]
(ii) Is element A, a metal or a non-metal? Give a reason for your choice.
[1]
[Total: 6]

4
3 Kinetic theory explains the properties of matter in terms of the arrangement and movement of
particles.
(a) Nitrogen is a gas at room temperature. Nitrogen molecules, N2, are spread far apart and
move in a random manner at high speed.
(i) Draw the electronic structure of a nitrogen molecule.

[2]
(ii) Compare the movement and arrangement of the molecules in solid nitrogen to those in
nitrogen gas.
[3]
(b) A sealed container contains nitrogen gas. The pressure of the gas is due to the molecules of
the gas hitting the walls of the container.
Use the kinetic theory to explain why the pressure inside the container increases when the
temperature is increased.
[2]
© UCLES 2014 0620/04/SP/16

5
The following apparatus can be used to measure the rate of diffusion of a gas.
constant
pressure
applied metal foil,
gas escapes
gas syringe gas through small
hole in foil
The following results were obtained.
temperature rate of diffusion

gas
/ °C in cm3 / min
nitrogen 25 1.00
chlorine 25 0.63
nitrogen 50 1.05
(c) (i) Explain why nitrogen gas diffuses faster than chlorine gas.
[2]
(ii) Explain why the nitrogen gas diffuses faster at the higher temperature.
[1]
[Total: 10]

6
4 Chromium is a transition element.
(a) (i) State two differences in the physical properties of chromium and sodium.
[2]
(ii) State two differences in the chemical properties of chromium and sodium.
[2]
(b) Chromium is used to electroplate steel objects. The diagram shows how this could be done.
+ –
lead anode object to

be plated
chromium(III)
sulfate(aq)
(i) Give two reasons why steel objects are plated with chromium.
[2]
(ii) The formula of the chromium(III) ion is Cr3+ and of the sulfate ion is SO42–. Give the
formula of chromium(III) sulfate.
[1]
(iii) Write the ionic half-equation for the reaction at the negative electrode (cathode).
[2]
(iv) A colourless gas, which relights a glowing splint, is formed at the positive electrode
(anode).
State the name of this gas.
[1]
© UCLES 2014 0620/04/SP/16

7
(v) During electroplating, it is necessary to add more chromium(III) sulfate but during
copper plating using a copper anode, it is not necessary to add more copper(II) sulfate.
Explain this difference.
[2]
[Total: 12]

8
5 Iron is extracted from its ore, hematite, in the blast furnace.
waste gases
raw materials::
coke, C
iron ore, Fe2O3
firebrick lining limestone, CaCO3
air
slag
molten iron
Describe the reactions involved in this extraction.
Include one equation for a redox reaction and one for an acid/base reaction.
[5]
[Total: 5]
© UCLES 2014 0620/04/SP/16

9
BLANK PAGE

10
6 Soluble salts can be made using a base and an acid.
(a) Complete this method of preparing dry crystals of the soluble salt
cobalt(II) chloride-6-water from the insoluble base cobalt(II) carbonate.
step 1
Add an excess of cobalt(II) carbonate to hot dilute hydrochloric acid.
step 2
step 3
step 4
[4]
© UCLES 2014 0620/04/SP/16

11
(b) (i) 5.95 g of cobalt(II) carbonate were added to 40 cm3 of hydrochloric acid, concentration
2.0 mol / dm3.
Calculate the maximum yield of cobalt(II) chloride-6-water and show that the cobalt(II)
carbonate was in excess.
CoCO3 + 2HCl → CoCl2 + CO2 + H2O
CoCl2 + 6H2O → CoCl2.6H2O
maximum yield:
number of moles of HCl used = ………………………………………………...…..…….
number of moles of CoCl2 formed = ……………………………………………..….……
number of moles of CoCl2.6H2O formed = ………………………………………..…..…
mass of one mole of CoCl2.6H2O = 238 g
maximum yield of CoCl2.6H2O = …………………………………………………..…..… g
to show that cobalt(II) carbonate is in excess:
number of moles of HCl used = ……………………….……… (use your value from above)
mass of one mole of CoCO3 = 119 g
number of moles of CoCO3 in 5.95 g of cobalt(II) carbonate = ………………………… [5]
(ii) Explain how these calculations show that cobalt(II) carbonate is in excess.
[1]
[Total: 10]

12
7 Iodine reacts with chlorine to form dark brown iodine monochloride.
I2 + Cl2 → 2ICl
This reacts with more chlorine to give yellow iodine trichloride.

An equilibrium forms between these iodine chlorides.
ICl(l) + Cl2(g) =⇌ ICl3(s)

dark brown yellow
(a) What do you understand by the term equilibrium?
[2]
(b) When the equilibrium mixture is heated, it becomes a darker brown colour.
Suggest if the reverse reaction is endothermic or exothermic. Give a reason for your choice.
[1]
(c) The pressure on the equilibrium mixture is decreased.
(i) How would this affect the position of equilibrium? Give a reason for your choice.
It would move to the
reason
[1]
(ii) Describe what you would observe.
[1]
© UCLES 2014 0620/04/SP/16

13
(d) Calculate the overall energy change for the reaction between iodine and chlorine using the
bond energy values shown.
I2 + Cl2 → 2ICl
Bond Energy / kJ per mol
I–I 151
Cl – Cl 242
I – Cl 208
Show your working.
[3]
(e) Draw a labelled energy level diagram for the reaction between iodine and chlorine using the
information in (d).
[2]
[Total: 10]

14
8 The alcohols form an homologous series.
(a) Give three characteristics of an homologous series.
[3]
(b) The following two alcohols are members of an homologous series and they are isomers.
CH3 ― CH2 ― CH2 ― CH2 ― OH and (CH3)2CH ― CH2 ― OH
(i) Explain why they are isomers.
[2]
(ii) Deduce the structural formula of another alcohol which is also an isomer of these
alcohols.
[1]
© UCLES 2014 0620/04/SP/16

15
(c) Copper(II) oxide can oxidise butanol to liquid X, whose pH is 4.
mineral wool
soaked in butanol copper(II) oxide
heat
liquid X
formed by
oxidation of
butanol.
(i) Give the name of another reagent which can oxidise butanol.
[1]
(ii) Which homologous series does liquid X belong to?
[1]
(iii) State the formula of liquid X.
[1]

16
(d) The alcohol ethanol can be made by fermentation. Yeast is added to aqueous glucose.
C6H12O6(aq) → 2C2H5OH(aq) + 2CO2(g)
Carbon dioxide is given off and the mixture becomes warm, as the reaction is exothermic.
The graph shows how the rate of reaction varies over several days.
rate of
reaction
time
(i) Suggest a method of measuring the rate of this reaction.
[2]
(ii) Why does the rate initially increase?
[1]
(iii) Suggest two reasons why the rate eventually decreases.
[2]
[Total: 14]
© UCLES 2014 0620/04/SP/16

17
BLANK PAGE

18
9 There are two types of polymerisation, addition and condensation.
(a) Explain the difference between these two types of polymerisation.
[2]
(b) Some plastics, formed by polymerisation, are non-biodegradable.
Describe two pollution problems that are caused by non-biodegradable plastics.
[2]
© UCLES 2014 0620/04/SP/16

19
(c) The polymer known as PVA is used in paints and adhesives. Its structural formula is shown
below.
―CH2―CH―CH2―CH―
│ │
OCOCH3 OCOCH3
Deduce the structural formula of its monomer.
[1]
(d) A condensation polymer can be made from the following monomers.
HOOC(CH2)4COOH and H2N(CH2)6NH2
Draw the structural formula of this polymer.
[3]
[Total: 8]
© UCLES 2014 0620/04/SP/16

20
© UCLES 2014 0620/04/SP/16

CHEMISTRY 0620/04
Paper 4 Theory (Extended) For Examination from 2016
1 hour 15 minutes
MAXIMUM MARK: 80

2
not do not allow
avp any valid point
© UCLES 2014 0620/04/SM/16

3
1 (a) A [1]
(b) D and F note: both needed for mark [1]
(c) E [1]
(d) B [1]
(e) C [1]
2 (a) (i) same number of protons and electrons [1]
(ii) all have the same number of protons / same proton number / same atomic number [1]
(iii) same number of protons / same proton number / same atomic number; [1]
different number of neutrons / different nucleon number / different mass number; [1]
(b) (i) 2, 8, 5 [1]
(ii) non-metal because it accepts electrons / needs 3e to complete outer energy level /
because it is in Group V or 5e in outer shell [1]
note: need both non-metal and reason for one mark
3 (a) (i) 6e between two nitrogen atoms; note: can be any combination of dots or crosses [1]
1 lone pair on each nitrogen atom; [1]
(ii) solid gas
pattern: regular / lattice random / irregular / no pattern; [1]
distance: close far apart / spread out; [1]
movement: vibrate / fixed position moving; [1]
note: comparison must be made
(b) particles have more energy / move faster; [1]

collide harder / collide more frequently / more collisions / collide with more force; [1]
allow: molecules instead of particles
(c) (i) nitrogen has smaller Mr; [1]

nitrogen (molecules) move faster (than chlorine molecules) / ora; [1]
(ii) (at higher temperature) molecules move faster / have more energy [1]
© UCLES 2014 0620/04/SM/16

4
4 (a) (i) Any two from:

chromium
is harder;
has higher density;
has higher melting point / boiling point;
stronger;
ora; [2]
(ii) Any two from:

sodium is more reactive;
chromium has more than one oxidation state, sodium has one;
chromium forms coloured compounds, sodium compounds are white;
sodium reacts with cold water, chromium does not;
chromium forms complex ions, sodium does not;
chromium has catalytic properties, sodium does not; [2]
note: difference must be clear
(b) (i) Any two from:

appearance / shiny / more attractive / decoration;
resists corrosion / resists rusting;
hard surface; [2]
(ii) Cr2(SO4)3 [1]

ignore: correct charges on ions
(iii) Cr3+ + 3e → Cr [2]

note: one mark for equation and one mark for correct balancing
(iv) oxygen / O2 [1]
(v) to replace chromium ions (used to plate steel) / chromium ions used up; [1]
copper ions replaced from copper anode; [1]
5 one redox equation from: [1]

Fe2O3 + 3CO → 2Fe + 3CO2
2Fe2O3 + 3C → 4Fe + 3CO2
Fe2O3 + 3C → 2Fe + 3CO
C + O2 → CO2
CO2 + C → 2CO
one acid/base equation: [1]

CaO + SiO2 → CaSiO3
CaCO3 + SiO2 → CaSiO3 + CO2
Any three additional equations or comments from: [3]

carbon burns or reacts to form carbon dioxide;
this reaction is exothermic or produces heat;
carbon dioxide is reduced to carbon monoxide;
carbon monoxide reduces hematite to iron;
carbon reduces hematite to iron;
limestone removes silica to form slag;
limestone decomposes;
© UCLES 2014 0620/04/SM/16

5
6 (a) filter / centrifuge / decant; [1]

(partially) evaporate / heat / boil; [1]
allow to crystallise / cool / let crystals form; [1]
dry crystals / dry between filter paper / leave in a warm place to dry; [1]
(b) (i) number of moles of HCl used = 0.04 × 2 = 0.08; [1]

number of moles CoCl2 formed = 0.04; [1]
number of moles CoCl2.6H2O formed = 0.04; [1]
maximum yield of CoCl2.6H2O = 9.52; [1]
allow: 9.5
allow: ecf on number of moles of HCl
number of moles of HCl used = 0.08 note: must use their value
allow: ecf
number of moles of CoCO3 in 5.95 g of cobalt(II) carbonate = 5.95/119 = 0.05; [1]
(ii) 0.05 > 0.04 or stated in words;

allow: ecf on number of moles of CoCl2 formed [1]
7 (a) rates equal; [1]

concentrations do not change / macroscopic properties remain constant; [1]
(b) endothermic and because this direction is favoured by high temperatures; [1]
note: reason is required
(c) (i) move to left hand side / reactants favoured and because bigger volume / more moles on
left hand side [1]
(ii) less (yellow) solid / more (dark brown) liquid / green gas visible / turns darker brown /
smell chlorine [1]
allow: ecf from (c)(i)
(d) (bond breaking =) 151 + 242 = 393; [1]

(bond making =) 208 × 2 = –416; not: 416 [1]
(overall =) 393 – 416 = –23; allow: ecf [1]
note: sign must be given
(e) Any two from:

diagram shows exothermic reaction;
activation energy shown;
reactants and products labelled / both axes labelled;
note: labelling is one mark only
allow: ecf from (d) [2]
© UCLES 2014 0620/04/SM/16

6
8 (a) Any three from:

same general formula;
consecutive members differ by CH2;
similar chemical properties;
same functional group;
physical properties vary in a predictable way / give trend such as mp increases with n; [3]
(b) (i) they have the same molecular formula; [1]

not: general formula
different structures / structural formulae; [1]
(ii) CH3-CH2-CH(OH)-CH3 / (CH3)3C-OH [1]

allow: butan-2-ol and 2-methylpropan-2-ol
(c) (i) (acidified) potassium manganate(VII) [1]

allow: oxygen / air / (acidified) potassium chromate(VI)
(ii) carboxylic acid [1]

allow: aldehyde / ketone
(iii) CH3-CH2-CH2-COOH / C3H7COOH / C4H8O2 [1]

allow: C4H7OOH
allow: ecf on (c)(ii)
(d) (i) measure volume of gas; [1]

measure time; [1]
(ii) increase in temperature / more yeast present / yeast multiplies [1]
(iii) glucose used up; [1]

concentration of ethanol high enough to kill yeast; [1]
9 (a) addition: polymer is the only product / only one product; [1]
condensation: polymer and water formed / small molecule formed; [1]
(b) Any two from:

ingestion can be fatal to animals / owtte;
animals can be caught in plastics e.g. fishing line / owtte;
combustion releases toxins / owtte;
land-fill uses natural resources / owtte;
allow: any appropriate example [2]
(c) CH2=CHOCOCH3 [1]

note: double bond does not need to be shown
(d) -OC(CH2)4CONH(CH2)6NH-
amide linkage correct; [1]
correct repeat units; [1]
continuation bonds shown; [1]
© UCLES 2014 0620/04/SM/16

*0123456789*
CHEMISTRY 0620/05
Paper 5 Practical Test For Examination from 2016
SPECIMEN PAPER
1 hour 15 minutes
Additional Materials: As listed in the Confidential Instructions

Notes for use in qualitative analysis are provided on pages 9 and 10.

2
1 You are going to investigate the reaction between excess magnesium and two different dilute
acids, X and Y.
Read all the instructions below carefully before starting the experiments.
Instructions
You are going to carry out two experiments.
(a) Experiment 1
Set up the apparatus as shown in the diagram below.
rubber connector stand and

clamp
bung
inverted 100 cm3
measuring cylinder
conical flask
water
trough
Remove the bung from the conical flask and move the measuring cylinder away from the
delivery tube without letting any water run out. Twist one of the strips of magnesium to break
it into four pieces and place all four pieces into the conical flask.
Using a different measuring cylinder, measure 50 cm3 of dilute acid X. Pour it into the conical
flask and replace the bung firmly. Place the measuring cylinder back over the delivery tube
and start the timer. In the table, record the volume of gas collected in the measuring cylinder
every 30 seconds for three minutes.
time / s 0 30 60 90 120 150 180
volume of gas / cm3

[2]
(b) Experiment 2
Repeat the whole of Experiment 1 using 50 cm3 of dilute acid Y.

In the table, record the volume of gas collected in the measuring cylinder every 30 seconds
for three minutes.
time / s 0 30 60 90 120 150 180
volume of gas / cm3

[2]
© UCLES 2014 0620/05/SP/16

3
(c) Plot the results you have obtained for both experiments on the grid below. For each set of
results, draw a smooth line graph. Indicate clearly which line represents Experiment 1 and
which line represents Experiment 2.
[4]
(d) State which experiment had the faster rate of reaction and suggest why the rate was faster in
this experiment.
[1]
(e) From your graph, deduce the time required to collect 25 cm3 of gas in Experiment 1.
Show clearly on the graph how you worked out your answer.
[1]

4
(f) The rate of this reaction can be calculated using:
volume of gas / cm 3
rate =
time taken / s
For the experiment with the higher rate, calculate the rate of reaction for the first 30 seconds
of the reaction. Deduce the units.
rate [2]
(g) A student suggested that the magnesium should be rubbed with sandpaper before starting
the experiment. Explain why the magnesium should be rubbed with sandpaper.
[2]
(h) Give one advantage and one disadvantage of using a measuring cylinder to add the acids to
the flask.
advantage
disadvantage [2]
(i) Suggest and explain one improvement to this experiment.
[1]
[Total: 17]
© UCLES 2014 0620/05/SP/16

5
BLANK PAGE

6
2 You are provided with a mixture of two solids, C and D. Solid C is water-soluble and D is
insoluble in water. Carry out the following tests on C and D, recording all of your observations at
each stage.
Add 15 cm3 of distilled water to the mixture in the boiling tube. Stopper and shake the boiling tube
for two minutes. Filter the contents of the tube, keeping the filtrate and residue for the following
tests.
tests on the filtrate
(a) (i) To about 1 cm3 of the solution, add a few drops of aqueous sodium hydroxide.
observation [1]
(ii) Now add excess aqueous sodium hydroxide to the mixture.
observation [1]
(b) To about 1 cm3 of the solution add an equal volume of aqueous ammonia.
observation [1]
(c) To about 1 cm3 of the solution add excess aqueous sodium hydroxide.
Now add a small piece of aluminium foil and warm the mixture carefully. Test any gases
given off.
observation
[2]
(d) Identify solid C.
[2]
tests on the residue
Wash the residue in the filter paper with a little distilled water.
Using a spatula, transfer some of the solid residue from the filter paper into two test-tubes.
(e) Heat the solid in the first test-tube gently and then strongly. Leave the test-tube to cool.
observation
[2]
© UCLES 2014 0620/05/SP/16

7
(f) (i) Add about 2 cm3 of dilute hydrochloric acid to the second test-tube. Test any gases given
off. Keep this liquid for (f)(ii).
observation
[2]
(ii) After two minutes, add an equal volume of distilled water and shake the test-tube.
Decant off the liquid and divide the liquid into two approximately equal portions.
To the first portion add aqueous sodium hydroxide a little at a time until in excess.
observation
[2]
(iii) To the second portion add aqueous ammonia a little at a time until in excess.
observation
[2]
(g) Identify solid D?
[2]
[Total: 17]

8
3 E-numbers identify chemicals which are added to foods.
(a) E210 is benzoic acid. How could you show that a solution of benzoic acid is a weak acid?
test
result [2]
(b) E110 is Sunset Yellow.

Outline a method you could use to show the presence of E110 in a food colouring.
You may draw a diagram to help answer the question.
[4]
[Total: 6]
© UCLES 2014 0620/05/SP/16

9
NOTES FOR USE IN QUALITATIVE ANALYSIS

Test for anions
carbonate (CO32–) add dilute acid effervescence, carbon dioxide

produced
bromide (Br –) acidify with dilute nitric acid, then add cream ppt.
nitrate (NO3–) add aqueous sodium hydroxide then ammonia produced

sulfate (SO42–) acidify, then add aqueous barium white ppt.

[in solution] nitrate
sulfite (SO32–) add dilute hydrochloric acid, warm sulfur dioxide produced will turn
gently and test for the presence of acidified aqueous potassium
sulfur dioxide manganate(VII) from purple to
colourless
Test for aqueous cations
aluminium (Al 3+) white ppt., soluble in excess giving a white ppt., insoluble in excess
colourless solution
calcium (Ca2+) white ppt., insoluble in excess no ppt., or very slight white ppt.
copper (Cu2+) light blue ppt., insoluble in excess light blue ppt., soluble in excess,
giving a dark blue solution
zinc (Zn2+) white ppt., soluble in excess giving a white ppt., soluble in excess, giving a
© UCLES 2014 0620/05/SP/16

10
Test for gases Flame tests for metal ions
gas test and test results metal ion flame colour
ammonia (NH3) turns damp, red litmus paper blue lithium (Li+) red
carbon dioxide (CO2) turns limewater milky sodium (Na+) yellow
chlorine (Cl 2) bleaches damp litmus paper potassium (K+) lilac
hydrogen (H2) ‘pops’ with a lighted splint copper(II) (Cu2+) blue-green
sulfur dioxide (SO2) turns acidified aqueous potassium

manganate(VII) from purple to
colourless
© UCLES 2014 0620/05/SP/16

CHEMISTRY 0620/05
Paper 5 Practical Test For Examination from 2016
1 hour 15 minutes
MAXIMUM MARK: 40

2
not do not allow
avp any valid point
© UCLES 2014 0620/05/SM/16

3
1 (a) volume, at time = 0 given; [1]

volume correctly completed in ascending order; [1]
allow: maximum of 2 consecutive identical numbers
(b) volume, at time = 0 given; [1]

(c) appropriate scale on x-axis and y-axis and labels and units; [1]
note: scale should cover at least half of grid
points plotted to ± half a small square accuracy;; [2]
note: >12 correct = 2, 10–12 correct = 1, <10 correct = 0
two labelled smooth line graphs and must plot volume at t = 0; [1]
(d) Experiment 1 / acid X and statement that acid X is stronger or more concentrated / ora [1]
(e) value from graph to ± half a small square accuracy and indication shown on graph [1]
(f) correct calculation of rate; [1]

allow: ecf on (d)
cm3 / s / cm3 s–1 / cm3 per s; [1]
allow: sec
(g) Any two from:

magnesium has an oxide coating;
rubbing exposes magnesium to the acid / removes oxide coating;
gives true rate / owtte; [2]
(h) advantage: convenient / easy / quick to use; [1]

disadvantage: reference to inaccurate measurement; [1]
(i) graduated pipette / burette / gas syringe / mass of magnesium rather than strips / repeats
and take average / take more frequent readings / suitable method for reducing initial loss of
gas and any suitable comment on improved accuracy; [1]
note: explanation must relate to reason
2 (a) (i) white precipitate [1]
(ii) no change / precipitate remains [1]
(b) no precipitate / slight (white) precipitate [1]
© UCLES 2014 0620/05/SM/16

4
(c) Any two from:

effervescence / fizz / bubbles;
(damp) pH paper blue / purple;
ammonia smell; [2]
(d) calcium; [1]

nitrate; [1]
(e) yellow / brown / orange colour when hot; [1]

colour fades / goes white when cool; [1]
(f) (i) effervescence / bubbles / fizz; [1]

limewater turns milky; [1]
(ii) white precipitate; [1]

precipitate dissolves in excess / colourless solution formed; [1]
(iii) white precipitate; [1]

(g) zinc; [1]

allow: aluminium dependent on (f)(iii)
carbonate; [1]
3 (a) Universal indicator / pH paper; [1]

pH of 3–6 / yellow / orange; [1]
note: any suitable test with appropriate result
(b) Any four from:

chromatography;
description of applying food colouring to paper;
use of solvent;
results / number of spots;
compare results to known sample / reference to Rf value; [4]
note: marks can be obtained from a labelled diagram
© UCLES 2014 0620/05/SM/16

*0123456789*
CHEMISTRY 0620/06
Paper 6 Alternative to Practical For Examination from 2016
SPECIMEN PAPER
1 hour


2
1 The diagram shows the apparatus used to prepare a dry sample of a gas. The gas is more dense
than air.
stand and
clamp
concentrated
sulfuric acid
(a) Complete the boxes to name the apparatus. [3]
(b) Identify one mistake in the apparatus.
[1]
(c) Suggest a reason why the gas is passed through concentrated sulfuric acid.
[1]
[Total: 5]
© UCLES 2014 0620/06/SP/16

3
2 A student investigated the rate of reaction between excess magnesium and two different dilute
acids, X and Y.
Two experiments were carried out.
Experiment 1
The apparatus was set up as shown in the diagram.

clamp
inverted
bung 100 cm3
measuring
cylinder
conical flask
trough water
Using a measuring cylinder, 50 cm3 of dilute acid X was poured into the conical flask.
0.5 g of magnesium ribbon was added to the conical flask and the bung added.
The timer was started and the volume of gas collected in the measuring cylinder was measured

4
(a) Use the measuring cylinder diagrams to record the volumes of gas collected.
measuring cylinder total volume of gas

time / s
diagram collected / cm3
0
0 5
10
10
30 15
20
20
60 25
30
25
90 30
35
30
120 35
40
40
150 45
50
45
180 50
55
[2]
© UCLES 2014 0620/06/SP/16

5
Experiment 2
Experiment 1 was repeated using 50 cm3 of dilute acid Y.
(b) Use the measuring cylinder diagrams to record the volumes of gas collected.

time / s
0
0 5
10
0
30 5
10
5
60 10
15
10
90 15
20
10
120 15
20
15
150 20
25
15
180 20
25
[2]

6
(c) Plot the results for both experiments on the grid below. For each set of results, draw a
smooth line graph. Indicate clearly which line represents Experiment 1 and which line
represents Experiment 2.
[4]
this experiment.
[1]
[1]
© UCLES 2014 0620/06/SP/16

7
rate =
time taken / s
rate [2]
(g) Give one advantage and one disadvantage of using a measuring cylinder to add the acids to
the flask.
advantage
disadvantage [2]
(h) Suggest and explain one improvement to this experiment.
[1]
[Total: 15]

8
3 Concentrated aqueous sodium chloride was broken down by electricity using the apparatus
shown.
gas A gas B
concentrated aqueous
sodium chloride
electrodes
+ –
(a) Suggest a suitable material from which to make the electrodes.
[1]
(b) Gas A is chlorine. Give a test for chlorine.
test
result [2]
(c) Gas B pops when tested with a lighted splint. What is gas B?
[1]
[Total: 4]
© UCLES 2014 0620/06/SP/16

9
BLANK PAGE

10
4 Solid E was analysed. E was an aluminium salt. Some of the observations are shown below.
tests on solid E observations
Appearance of solid E. white crystalline solid
test 1
colourless drops of liquid formed at the top of
the tube
A little of solid E was heated in a test-tube.
(a) A little of solid E was dissolved in distilled water.
The solution was divided into four test-tubes and the following tests were carried out.
Complete the observations for tests 2 and 3.
(i) test 2
Drops of aqueous sodium hydroxide were added to the first test-tube.
observations [1]
(ii) Excess sodium hydroxide was then added.
observations [1]
(iii) test 3
Drops of aqueous ammonia solution were added to the second test-tube. Excess
ammonia solution was then added.
observations
[2]
Two further tests are carried out and the following observations made.
tests on solution of E observations
test 4
To the third test-tube of solution, dilute no reaction

hydrochloric acid was added, followed by
barium nitrate solution.
test 5
effervescence
To the fourth test-tube of solution, aqueous
sodium hydroxide and aluminium foil were pungent gas given off
added.
gas turned damp litmus paper blue
The mixture was warmed carefully.
© UCLES 2014 0620/06/SP/16

11
(b) What does test 1 tell you about solid E?
[1]
(c) Identify the gas given off in test 5.
[1]
(d) What conclusions can you draw about solid E?
[2]
(e) Test 5 states that the mixture should be warmed carefully.
In terms of safety, explain why it is necessary to warm carefully.
[2]
[Total: 10]

12
test
result [2]

[4]
[Total: 6]
© UCLES 2014 0620/06/SP/16

CHEMISTRY 0620/06
Paper 6 Alternative to Practical For Examination from 2016
1 hour
MAXIMUM MARK: 40

2
not do not allow
avp any valid point
© UCLES 2014 0620/06/SM/16

3
1 (a) tap / separating / dropping funnel; [1]

not: burette
delivery tube; [1]
gas jar; [1]
allow: measuring cylinder
(b) gas should be collected downwards / owtte [1]
(c) to remove water / to remove impurities [1]
2 (a) volume boxes completed correctly 0, 13, 22, 30, 36, 43, 49
note: all 7 correct = 2, 6 correct = 1, <6 correct = 0 [2]
(b) volume boxes completed correctly 0, 5, 10, 13, 17, 20, 23

(e) 71–73 s and indication shown on graph; [1]

allow: ecf from incorrect graph
(f) 13 ÷ 30 = 0.43; [1]

allow: 0.4
allow: ecf on plotting
cm3 / s / cm3 s–1 / cm3 per s; [1]
allow: sec
(g) advantage: convenient / easy / quick to use; [1]

(h) graduated pipette / burette / gas syringe / mass of magnesium rather than strips / repeats
© UCLES 2014 0620/06/SM/16

4
3 (a) platinum / graphite / carbon [1]
(b) damp blue litmus paper / Universal indicator paper / pH paper; [1]
bleaches / turns white; [1]
(c) hydrogen [1]
(ii) precipitate dissolves in excess; [1]

no change / precipitate remains; [1]
(b) contains water / hydrated [1]
(c) ammonia
not: ammonium [1]
(d) Any two from:

nitrate;
hydrated salt / contains water;
it is not a sulfate; [2]
(e) sodium hydroxide is hazardous / irritant / caustic; [1]

allow: toxic
boiling causes mixture to spit / blow-out; [1]

(b) Any four from:

chromatography;
use of solvent;
marks can be obtained from a labelled diagram
© UCLES 2014 0620/06/SM/16

Cambridge IGCSE®
CHEMISTRY 0620/01
*0123456789*
Paper 1 Multiple Choice (Core) For examination from 2020

SPECIMEN PAPER
45 minutes
Additional materials: Multiple choice answer sheet
Soft clean eraser

Write your name, centre number and candidate number on the answer sheet in the spaces provided unless
Choose the one you consider correct and record your choice in soft pencil on the separate answer sheet.
Read the instructions on the answer sheet very carefully.

2

D The substance in state 3 has a fixed volume.
2 What is always true for a pure substance?
A It always boils at 100 °C.

B It contains only one type of atom.
C It has a sharp melting point.
D It is solid at room temperature.
3 Element Y has a nucleon number of 19 and a proton number of 9.
Which group in the Periodic Table does it belong to?
A I B III C VII D VIII
7
4 The nucleon number and proton number of the lithium atom are shown by the symbol 3
Li.
6 6 7 7
A 2
Li– B 3
Li+ C 3
Li+ D 3
Li–
5 What is the relative molecular mass, Mr, of HNO3?
A 5 B 31 C 32 D 63
© UCLES 2017 0620/01/SP/20

3
particle proton nucleon number of number of number of

Mg 12 24 12 W 12
Mg2+ X 24 12 12 10
F 9 19 9 Y 9
F– 9 19 9 10 Z
W X Y Z
A 10 10 9 9
B 10 12 10 9
C 12 10 9 10
D 12 12 10 10
key
+ = proton
+ +
– – n = neutron
n n
– = electron
A B C D
+ + + + + + + + + + +
– – – – – – – –
n n n n n n n n n

4
R 2,4
T 2,8
X 2,8,1
Z 2,8,7
9 Element X forms an acidic, covalent oxide.
Which row shows how many electrons there could be in the outer shell of an atom of X?
1 2 6 7
A 9 9 8 8
B 9 8 9 8
C 8 8 9 9
D 8 9 8 9
10 Which diagram does not show the outer shell electrons in the molecule correctly?
A B C D
H H H Cl H C H Cl Cl
W NaAl Si3O8
X CaAl2Si2O8
© UCLES 2017 0620/01/SP/20

5
12 The diagram shows apparatus used in an attempt to electroplate a metal ring with copper.
battery
+ –
bulb
metal ring copper electrode

aqueous copper(II)
sulfate (electrolyte)
The experiment did not work.
Which change is needed in the experiment to make it work?
A Add solid copper(II) sulfate to the electrolyte.

B Increase the temperature of the electrolyte.
C Replace the copper electrode with a carbon electrode.
D Reverse the connections to the battery.

6
14 Which process is not exothermic?
A burning a fossil fuel

B obtaining lime from limestone
C radioactive decay of 235U
D reacting hydrogen with oxygen
gas syringe
reaction mixture
© UCLES 2017 0620/01/SP/20

7
R
volume of S
hydrogen
given off
time
17 When pink cobalt(II) chloride crystals are heated they form steam and a blue solid.
When water is added to the blue solid, it turns pink and becomes hot.
Which terms describe the pink cobalt(II) chloride crystals and the reactions?
pink cobalt(II) chloride reactions
A aqueous irreversible
B anhydrous reversible
C hydrated irreversible
D hydrated reversible

8
heat
CuCO3 CuO + CO2
CuO + SnO Cu + SnO2
1 2
A CO2 SnO2
B CuCO3 CuO
C CuO SnO
D SnO CuO
19 Carbon dioxide gas reacts with aqueous sodium hydroxide.
A decomposition
B fermentation
C neutralisation
D oxidation
20 An aqueous solution of the organic compound methylamine has a pH greater than 7.
Which statement about methylamine is correct?
A It neutralises an aqueous solution of sodium hydroxide.

B It reacts with copper(II) carbonate to give carbon dioxide.
C It reacts with hydrochloric acid to form a salt.
D It turns blue litmus red.
A chloride only
B nitrate only
C sulfate only
© UCLES 2017 0620/01/SP/20

9
test result



small amounts.

colour state
potassium iodide


10
24 The diagram shows the positions of elements L, M, Q, R and T in the Periodic Table.
These letters are not the chemical symbols of the elements.
R T
M Q
Which statement about the properties of these elements is correct?
A L reacts more vigorously with water than does M.

B L, M and Q are all metals.
C T exists as diatomic molecules.
D T is more reactive than R.
25 The table compares the properties of Group I elements with those of transition elements.
Which entry in the table is correct?
property Group I elements transition elements
A catalytic activity low high

B density high low
C electrical conductivity low low
D melting point high low
gas X
Which statement about gas X is correct?
A X burns in air.
B X is coloured.
C X is unreactive.
© UCLES 2017 0620/01/SP/20

11
27 Aluminium is an important metal with many uses.
Some of its properties are listed.
1 It is a good conductor of heat.
2 It has a low density.
3 It has an oxide layer that prevents corrosion.
Which set of properties help to explain the use of aluminium for cooking and storing food?
A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3
28 Which diagram could represent the structure of an alloy?
A B
– + – +
+ – + –
– + – +
C D

12
water.
A P R Q
B P Q R
C R Q P
D R P Q
A W only
B W, X and Z
C W and Y only
D W, Y and Z
© UCLES 2017 0620/01/SP/20

13

carbon
heat
limewater
What is compound X?
A calcium oxide
B copper(II) oxide
C magnesium oxide
D sodium oxide
heat with an
ammonium compound
ammonia
substance Y
a salt
heat with
dilute acid
A an alcohol
B a base
C a catalyst
D a metal

14
33 A test-tube containing damp iron wool is inverted in water.
After three days, the water level inside the test-tube has risen.
damp iron wool
water
Which statement explains this rise?
A Iron oxide has been formed.

B Iron wool has been reduced.
C Oxygen has been formed.
D The temperature of the water has risen.
Gas «..1«.. is produced by process «..3«.. .
Gas «..2«.. is produced by process «..4«.. .
Which row correctly complete gaps 1, 2, 3 and 4?
1 2 3 4

© UCLES 2017 0620/01/SP/20

15
35 To grow rose plants, a fertiliser containing nitrogen, phosphorus and potassium is often used.
For the best rose flowers, the fertiliser should contain a high proportion of potassium.
Which fertiliser is best for producing rose flowers?
proportion by mass
fertiliser
N P K
A 9 0 25
B 13 13 20
C 29 5 0
D 29 15 5
substance X.
substance X
A calcium oxide
B sand
C sodium chloride

16
refinery gases
gasoline
X
pre-heat diesel oil
400 °C Y
Z
X Y Z

38 The structures of three compounds are shown.
H H H H H H H H H H
C C H C C C C H H C C C C C C H
H H H H H H H H H H
A They all contain an even number of carbon atoms.

C They are all hydrocarbons.
D They are all saturated.
39 Which bond is not in a molecule of ethanoic acid?
A C–O B C=O C C=C D O–H
© UCLES 2017 0620/01/SP/20

17
40 Which structure is incorrect?
A B C D
H H H O H H H H
H C C H H C C O H H C C H H C C O H
H H H H H H H
© UCLES 2017 0620/01/SP/20

18
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of
Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2017 0620/01/SP/20

Cambridge IGCSE®
CHEMISTRY 0620/01
Paper 1 Multiple Choice (Core) For examination from 2020
MARK SCHEME
Maximum Mark: 40
Specimen

2
Question Question
Key Key
Number Number
1 D 21 B
2 C 22 B
3 C 23 A
4 C 24 B
5 D 25 A
6 D 26 C
7 A 27 D
8 C 28 D
9 C 29 A
10 D 30 D
11 B 31 B
12 D 32 B
13 A 33 A
14 B 34 D
15 C 35 B
16 B 36 A
17 D 37 D
18 D 38 B
19 C 39 C
20 C 40 C
© UCLES 2017 0620/01/SM/20

Cambridge IGCSE®
CHEMISTRY 0620/02
*0123456789*
Paper 2 Multiple Choice (Extended) For examination from 2020

SPECIMEN PAPER
45 minutes
Additional materials: Multiple choice answer sheet
Soft clean eraser

Write your name, centre number and candidate number on the answer sheet in the spaces provided unless
Choose the one you consider correct and record your choice in soft pencil on the separate answer sheet.
Read the instructions on the answer sheet very carefully.

2
1 Amino acids are colourless and can be separated and identified by chromatography.
glass cover
beaker
chromatography
paper solvent
What additional apparatus is required to identify the amino acids present in a mixture?
A a locating agent
B a ruler
C a ruler and a locating agent
D neither a ruler or a locating agent
2 The diagram shows the diffusion of hydrogen chloride and ammonia in a glass tube.
The gases are given off by the solutions at each end of the tube.
When hydrogen chloride and ammonia mix they produce a white solid, ammonium chloride.
Which line shows where the white solid is formed?
A B C D

concentrated ammonia concentrated
solution hydrochloric acid
© UCLES 2017 0620/02/SP/20

3
key
+ = proton
+ +
– – n = neutron
n n
– = electron
A B C D
+ + + + + + + + + + +
– – – – – – – –
n n n n n n n n n

particle
Mg 12 24 12 W 12
Mg2+ X 24 12 12 10
F 9 19 9 Y 9
F– 9 19 9 10 Z
W X Y Z
A 10 10 9 9
B 10 12 10 9
C 12 10 9 10
D 12 12 10 10

4
5 Iron is a metal. The structure of iron is described as a lattice of positive ions in a sea of electrons.
Which of the following statements about iron are correct?
1 iron conducts electricity because the electrons are free to move
2 iron has a high melting point due to the strong covalent bonds
3 iron is an alloy
4 iron is malleable because the layers of atoms can slide over one another
A 1 only
B 1 and 3
C 1 and 4
D 2, 3 and 4
R 2,4
T 2,8
X 2,8,1
Z 2,8,7
7 Ethene is an unsaturated hydrocarbon.
H H
C C
H H
Which description of the bonding in ethene is correct?
A All atoms in the molecule have a share of eight electrons.

B Each carbon atom shares two of its electrons with hydrogen atoms and two of its electrons
with a carbon atom.
C Each carbon atom shares two of its electrons with hydrogen atoms and one of its electrons
with a carbon atom.
D The two carbon atoms share a total of six electrons with other atoms.
8 What is the relative molecular mass, Mr, of butanol?
A 15 B 37 C 74 D 148
© UCLES 2017 0620/02/SP/20

5
W NaAl Si3O8
X CaAl2Si2O8
10 What is the concentration of a solution containing 1.0 g of sodium hydroxide in 250 cm3 of
solution?
A 0.025 mol / dm3

B 0.10 mol / dm3
C 0.25 mol / dm3
D 1.0 mol / dm3
11 Four students prepared hydrated copper(II) sulfate by adding an excess of dilute sulfuric acid to
copper(II) oxide.
Each student used a different mass of copper(II) oxide.

CuO CuSO4.5H2O
Mr = 80 Mr = 250
After the copper(II) sulfate had crystallised the students dried and weighed the crystals.
Which student produced the highest percentage yield of hydrated copper(II) sulfate?
mass of copper(II) mass of crystals

oxide used / g produced / g
A 4.0 11.5
B 8.0 23.5
C 12.0 35.0
D 16.0 46.5

6
12 20 cm3 of ethyne, C2H2, are reacted with 500 cm3 of oxygen.
The equation for the reaction is
2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(l)
What is the total volume of gas remaining at the end of the reaction?
(all volumes are measured at room temperature and pressure)
A 400 cm3
B 450 cm3
C 490 cm3
D 520 cm3
13 Different metals were tested using the apparatus shown.
V
metal 1 metal 2
Which pair of metals would produce the largest voltage?
A copper and silver

B magnesium and silver
D zinc and copper
© UCLES 2017 0620/02/SP/20

7
15 The statements refer to the electrolysis of concentrated copper(II) chloride solution.
2 Electrons move around the circuit from the cathode to the anode.
Which statements about the electrolysis of concentrated copper(II) chloride are correct?
A 1 and 3
B 1 and 4
C 2 and 3
D 2 and 4
16 Water can be used to produce hydrogen gas.
2H2O → 2H2 + O2
Which row describes bond breaking in the reactant?
A endothermic heat absorbed

B endothermic heat released
C exothermic heat absorbed
D exothermic heat released
17 Dinitrogen tetroxide, N2O4, breaks down into nitrogen dioxide, NO2.
N2O4(g) ⇌ 2NO2(g)
The reaction is reversible and endothermic.
Which conditions will give the largest yield of nitrogen dioxide, NO2?
A high high
B high low
C low high
D low low

8
gas syringe
reaction mixture
R
volume of S
hydrogen
given off
time
© UCLES 2017 0620/02/SP/20

9
20 Which of these reactions shows only reduction?
A Cu2+ + 2e– p Cu
B Fe2O3 + 3CO p 2Fe + 3CO2
C HCl + NaOH p NaCl + H2O
D Mg + ZnSO4 p Zn + MgSO4
heat
CuCO3 CuO + CO2
CuO + SnO Cu + SnO2
1 2
A CO2 SnO2
B CuCO3 CuO
C CuO SnO
D SnO CuO
22 Acids are compounds which donate protons (hydrogen ions).
NH3(aq) + H2O(l) → NH4+(aq) + OH–(aq)
Which compound in this equation is behaving as an acid?
A ammonia
B ammonium hydroxide
C none of them
D water

10
23 The reactions of four different oxides W, X, Y and Z are shown.
W reacts with hydrochloric acid but not sodium hydroxide.
X reacts with both hydrochloric acid and sodium hydroxide.
Y does not react with either hydrochloric acid or sodium hydroxide.
Z reacts with sodium hydroxide but not hydrochloric acid.
Which row shows the correct types of oxide?
acidic basic amphoteric neutral
A W Z X Y
B X Y W Z
C Z X Y W
D Z W X Y
A chloride only
B nitrate only
C sulfate only
test result



© UCLES 2017 0620/02/SP/20

11
The letters are not the chemical symbols of the elements.
W X
Z Y
Which statement about the elements is not correct.
A W has two electrons in the outermost shell.

B Y is in Group IV of the Periodic Table.
C X and Y bond covalently to form a molecule XY4.
D Z has more metallic character than Y.
small amounts.

colour state
potassium iodide

12
water.
A P R Q
B P Q R
C R Q P
D R P Q

carbon
heat
limewater
What is compound X?
A calcium oxide
B copper(II) oxide
C magnesium oxide
D sodium oxide
© UCLES 2017 0620/02/SP/20

13
30 Zinc is extracted from zinc blende. Zinc blende is an ore of zinc and consists mainly of zinc
sulfide.
One of the steps in the process involves zinc sulfide reacting with oxygen from the air.
What is the equation for this reaction?
A 2ZnS + 3O2 → 2ZnO + 2SO2
B 2ZnS + O2 → 2Zn + SO2
C 2ZnS + O2 → 2ZnO + S
D ZnS + 2O2 → ZnSO4
31 The diagram shows the carbon cycle.
carbon dioxide in
atmosphere
gradual production of
fossil fuels
coal, oil
and
natural gas
Which process is shown by the arrow marked X?
A combustion
B photosynthesis
C respiration
D transpiration

14
32 A catalytic converter removes harmful gases from motor car exhausts.
Which reaction does not take place in a catalytic converter?
A 2CO + O2 → 2CO2
B N2 + 2CO2 → 2NO + 2CO
C 2NO2 → N2 + 2O2
D 2NO2 + 4CO → N2 + 4CO2
heat with an
ammonium compound
ammonia
substance Y
a salt
heat with
dilute acid
A an alcohol
B a base
C a catalyst
D a metal
© UCLES 2017 0620/02/SP/20

15
34 Which row shows the conditions for the manufacture of sulfuric acid?
pressure / atm temperature / °C catalyst
A 2 450 vanadium(V) oxide

B 2 250 iron
C 200 450 iron
substance X.
substance X
A calcium oxide
B sand
C sodium chloride

16
refinery gases
gasoline
X
pre-heat diesel oil
400 °C Y
Z
X Y Z

37 Which reaction does not take place in the dark?
A CH4 + 2O2 → CO2 + 2H2O

B CH4 + Cl2 → CH3Cl + HCl
C C2H4 + H2O → C2H5OH
D C2H4 + H2 → C2H6
38 Ethane and ethene are both hydrocarbons.
Ethane reacts with chlorine and ethene reacts with bromine.
Which row describes the type of reaction that ethane and ethene undergo?
ethane ethene
A addition addition
B addition substitution
C substitution substitution
D substitution addition
© UCLES 2017 0620/02/SP/20

17
39 Esters are made by reacting an alcohol with a carboxylic acid.
Which acid and alcohol react together to form the following ester?
O
CH3CH2 C
OCH3
A propanoic acid and ethanol

B propanoic acid and methanol
C ethanoic acid and ethanol
D ethanoic acid and methanol
40 Which structure represents a polymer?
H O H O
C N C N C N C
H O
© UCLES 2017 0620/02/SP/20

18
© UCLES 2017 0620/02/SP/20

Cambridge IGCSE®
CHEMISTRY 0620/02
Paper 2 Multiple Choice (Extended) For examination from 2020
MARK SCHEME
Maximum Mark: 40
Specimen

2
Question Question
Key Key
Number Number
1 C 21 D
2 D 22 D
3 A 23 D
4 D 24 B
5 C 25 B
6 C 26 C
7 B 27 A
8 C 28 A
9 B 29 B
10 B 30 A
11 B 31 C
12 C 32 B
13 B 33 B
14 A 34 A
15 A 35 A
16 A 36 D
17 B 37 B
18 C 38 D
19 B 39 B
20 A 40 C
© UCLES 2017 0620/02/SM/20

Cambridge IGCSE®
CHEMISTRY 0620/03
*0123456789*
Paper 3 Theory (Core) For examination from 2020

SPECIMEN PAPER
1 hour 15 minutes
Candidates answer on the question paper.
No additional materials are required.
Write your centre number, candidate number and name on all the work you hand in.


2
1 The structures of diamond and chlorine are shown below.
diamond chlorine
= carbon atom = chlorine atom
(a) Describe the structure of these two substances.

Use the list of words to help you.
covalent diatomic giant macromolecule molecule structure
diamond
chlorine
[4]
(b) The structure of a compound containing carbon and chlorine is shown below.
Cl Cl
Cl Cl
C
Cl C C Cl
Cl C C Cl
C
Cl Cl
Cl Cl
What is the molecular formula of this compound?
[1]
© UCLES 2017 0620/03/SP/20

3
(c) Chlorine is a halogen.
(i) State the colour of chlorine.
[1]
The table shows some properties of the halogens.
density in liquid
element boiling point / °C colour
state / g per cm3
fluorine –188 1.51 yellow
chlorine –35 1.56
bromine –7 red-brown
iodine +114 4.93 grey-black
Use the information in the table to answer the following questions.
(ii) Predict the density of liquid bromine.
[1]
(iii) Describe the trend in boiling point of the halogens down the group.
[1]
(d) (i) Complete the word equation for the reaction of bromine with aqueous potassium iodide.
bromine + potassium iodide → «««««««... + «««««««...
«««««««... [2]
(ii) Suggest why bromine does not react with aqueous potassium chloride.
[1]
(e) Potassium chloride is an ionic substance but iodine is a molecular substance.

How do most ionic and molecular substances differ in their
solubility in water?
electrical conductivity?
[2]
[Total: 13]

4
2 Bromine is an element in Group VII of the Periodic Table.
(a) State the formula for a molecule of bromine.
[1]
(b) A teacher placed a small amount of liquid bromine in the bottom of a sealed gas jar of air.
After two minutes red-brown fumes were seen just above the liquid surface. After one hour
the red-brown colour had spread completely throughout the gas jar.
air
liquid
bromine
start after 2 minutes after 1 hour
Use the kinetic particle model of matter to explain these observations.
[3]
[Total: 4]
© UCLES 2017 0620/03/SP/20

5
3 The structures of some substances containing nitrogen are shown below.
A B C
K+ NO3– K+
N N
H H NO3– K+ NO3– I I
H I
K+ NO3– K+
D E
N
N N O O

(a) an acidic oxide, [1]
(b) an ionic structure, [1]
(c) a gas which turns damp red litmus paper blue, [1]
(d) a compound which is formed under conditions [1]

(e) a molecule containing halogen atoms, [1]
(f) a salt? [1]
[Total: 6]

6
4 The diagram shows a rotary lime kiln used to make lime from limestone.
Limestone is fed in at the top of the kiln and lime comes out at the bottom.
kiln moves air out

round limestone
hot air
lime
(a) State the chemical name for lime.
[1]
(b) State the name of the type of chemical reaction that takes place in the kiln.
[1]
(c) Suggest why the air coming out of the kiln has a greater percentage of carbon dioxide than
the air entering the kiln.
[1]
(d) State one use for lime.
[1]
(e) A student compared the rates of reaction of three metal carbonates.

She measured the volume of gas released using the apparatus shown.
gas syringe
metal carbonate
heat
State one thing that must be kept constant if the rates of the three reactions are to be
compared in a fair way.
[1]
© UCLES 2017 0620/03/SP/20

7
(f) The graph shows the volume of carbon dioxide released when the three metal carbonates
were heated.
50
calcium
40 carbonate
30 strontium
volume of carbonate
carbon dioxide
/ cm3
20
barium
carbonate
10
0
0 2 4 6 8 10 12
time / minutes
(i) Which carbonate produced carbon dioxide at the highest rate?
[1]
(ii) What volume of carbon dioxide was produced by strontium carbonate in twelve minutes?
[1]
(iii) How do the rates of the reactions of these three metal carbonates relate to the position
of calcium, strontium and barium in the Periodic Table?
[2]
(g) Describe how hydrochloric acid and limewater can be used to show that carbonate ions are
present in calcium carbonate.
[3]
[Total: 12]

8
5 Iron is a transition element.
(a) State three properties of transition elements which are not shown by the Group I elements.
1.
2.
3. [3]
(b) The symbols for two isotopes of iron are shown below.
54 57
26
Fe 26
Fe
[1]
57
(ii) Determine the number of neutrons present in one atom of the isotope 26
Fe.
[1]
(iii) Determine the number of electrons in one Fe3+ ion?
[1]
(c) Pure iron rusts very easily.
Describe and explain one method of preventing rusting.
method
explain why this method works
[2]
(d) Iron can be recycled.
Explain two advantages of recycling metals.
[2]
© UCLES 2017 0620/03/SP/20

9
(e) In the blast furnace, iron(III) oxide reacts with carbon monoxide.
Fe2O3 + 3CO → 2Fe + 3CO2
Which substance gets reduced in this reaction?

substance
explanation
[2]
(f) (i) Carbon monoxide is a pollutant gas produced in motor car engines.
State why carbon monoxide is formed.
[1]
(ii) State one harmful effect of carbon monoxide.
[1]
[Total: 14]

10
6 Concentrated hydrochloric acid can be electrolysed using the apparatus shown.
concentrated
hydrochloric acid

+ –
(a) Define the term electrolysis.
[1]


[1]
[1]
Electrodes made of graphite or «««««««« are generally used in electrolysis
because they are «««««««« . [2]
© UCLES 2017 0620/03/SP/20

11
(e) When concentrated hydrochloric acid is electrolysed, chlorine is released.
(i) Draw the shells and the electronic structure in an atom of chlorine.
[1]

[2]
test
result [2]
hydrochloric acid + calcium hydroxide → «««««««« + ««««««««
«««««««« [2]

Zn + ........HCl → ZnCl2 + ........

[2]
[Total: 14]

12
7 The pie chart shows the composition of air.
nitrogen
oxygen
other gases
(a) (i) What is the percentage of nitrogen in the air?
[1]
(ii) Apart from nitrogen and oxygen, state the names of two gases present in unpolluted air.
and [2]
(b) The percentage of oxygen in air can be found using the apparatus shown below.
air copper wire air
gas syringe
heat
Air is passed backwards and forwards over the heated copper using the syringes. The
copper reacts with oxygen in the air.
copper + oxygen → copper(II) oxide
As the experiment proceeds, suggest what happens to
(i) the total volume of air in the gas syringes,
[1]
(ii) the mass of the wire in the tube.
[1]
(c) State one use of copper.
[1]
[Total: 6]
© UCLES 2017 0620/03/SP/20

13
8 Ethene, C2H4, is manufactured by cracking petroleum fractions.
(a) (i) What do you understand by the term fraction?
[1]
(ii) Complete the symbol equation for the manufacture of ethene from dodecane, C12H26.
C12H26 → C2H4 + ««««

[1]
(b) Two fractions obtained from the distillation of petroleum are refinery gas and gasoline.
State one use of each of these fractions.
refinery gas
gasoline [2]
(c) Ethene is an unsaturated hydrocarbon.

What do you understand by the following terms?
unsaturated
hydrocarbon [2]
(d) Ethene is used to make ethanol.
(i) Which of these reactions is used to make ethanol from ethene?

Tick one box.
catalytic addition of steam
fermentation
oxidation using oxygen
reduction using hydrogen

[1]

14
(ii) Draw the structure of ethanol, showing all atoms and bonds.
[2]
(e) Ethene is used to make poly(ethene).

Complete the following sentences about this reaction.
additions carbohydrates catalysts monomers polymers
The ethene molecules which join to form poly(ethene) are the .
The poly(ethene) molecules formed are . [2]
[Total: 11]
© UCLES 2017 0620/03/SP/20

15
BLANK PAGE
© UCLES 2017 0620/03/SP/20

16
© UCLES 2017 0620/03/SP/20

Cambridge IGCSE®
CHEMISTRY 0620/03
Paper 3 Theory (Core) For examination from 2020
MARK SCHEME
Maximum Mark: 80
Specimen

2
not do not allow
avp any valid point
© UCLES 2017 0620/03/SM/20

3
1 (a) diamond:
covalent;
giant structure / macromolecule;
chlorine: any two of:
molecule;
covalent;
diatomic; [4]
(b) C6Cl12 [1]
(c) (i) green / yellow-green / light green [1]
(ii) value between 2.5–4(.0) (g per dm3) (actual = 3.12) [1]
(iii) increases [1]
(d) (i) potassium bromide [1]

not: potassium bromine
iodine [1]
not: iodide
(ii) chlorine is more reactive than bromine / ora [1]

not: chloride is more reactive than bromide
(e) solubility in water:

ionic compounds are soluble and molecular compounds are not soluble [1]
electrical conductivity:
ionic compounds conduct electricity when molten / in (aqueous) solution
and molecular compounds do not [1]
2 (a) Br2 [1]
(b) Any three of: [3]

• bromine evaporates / liquid evaporates;
• more energetic particles change from liquid to vapour or gas;
• diffusion;
• random movement of particles / particles move everywhere / air and bromine particles
are moving;
• (bromine and air) particles get mixed up / collision of bromine and air particles;
allow: molecules in place of particles

4
(d) E / nitrogen (di)oxide / NO2 [1]
(e) C / NI3 / nitrogen (tri)iodide [1]
4 (a) calcium oxide [1]

allow: CaO
(b) thermal decomposition [1]
(c) carbon dioxide has been removed from the limestone / it comes from the limestone / carbon
dioxide is a product [1]
(d) neutralising acidic soils / treating acidic lakes / flue gas desulfurisation
allow: any suitable use [1]
(e) temperature of Bunsen / distance of Bunsen from the tube / mass of carbonate used / owtte
[1]
(f) (i) calcium carbonate [1]
(ii) 27 (cm3) [1]
(iii) calcium faster than strontium which is faster than barium / idea of
trend down the group; [1]
correct trend, i.e. less rapid reaction the further down the group / ora; [1]
(g) add acid to carbonate; [1]

bubble gas or carbon dioxide (evolved) through limewater / test gas or carbon
dioxide with limewater; [1]
limewater goes milky or cloudy; [1]
© UCLES 2017 0620/03/SM/20

5
5 (a) Any three of:

high melting / boiling point;
high density;
form coloured compounds or have coloured ions;
form ions of more than one charge / variable valency / variable oxidation state;
allow: form complex ions; hard / hardness; catalysts; [3]
(b) (i) different number of neutrons / different nucleon number [1]
(ii) 31 [1]
(iii) 23 [1]
(c) suitable method, e.g. coating with paint / zinc / unreactive metal / plastic / oil / grease /
galvanising / sacrificial protection; [1]
suitable reason, e.g. stops air / water reaching surface; [1]
note: reason must be consequential to the method chosen
(d) Any two of:

recycling promotes sustainable development / owtte;
uses less energy than extraction;
preserves limited natural resources;
correct reference to cost;
reference to landfill; [2]
(e) Fe2O3 / iron oxide; [1]

it loses oxygen / gains electrons / iron decreases oxidation number; [1]
(f) (i) incomplete combustion / insufficient or limited or not enough oxygen [1]
(ii) toxic / suffocates you / stops red blood cells carrying oxygen / binds with hemoglobin in
place of oxygen [1]
6 (a) break down (of substance / electrolyte) by electricity / splitting up of substance by electricity /
allow: current / voltage for electricity
(b) anode [1]
(c) hydrogen [1]

allow: H2
(d) platinum; [1]

inert; [1]

6
(e) (i) 2,8,7 as shown in an electron shell diagram [1]
(ii) pair of electrons between two chlorine atoms; [1]

rest of electrons correct; [1]
(iii) (damp) litmus (paper) / Universal indicator (paper); [1]

allow: indicator paper / pH paper
bleaches / goes white / goes red then bleaches; [1]

not: calcium chlorine
(ii) 2 on left; [1]

H2 on right; not: 2H [1]
7 (a) (i) 78 (%) [1]

allow: 78–80
(ii) Any two of: [2]

carbon dioxide; argon; neon; xenon; helium; radon; water;
not: hydrogen
(b) (i) decreases / gets less / gets lower / gets used up [1]
(ii) increases / gets more / greater [1]
(c) any suitable use e.g. electrical conductor / electrical wiring / saucepans [1]
8 (a) (i) (group of) molecules with similar boiling points / (group of) molecules with similar relative
molecular masses / molecules with limited range of boiling points / molecules with limited
range of molecular masses / molecules coming off at the same place in the fractionation
column / owtte [1]
(ii) C10H22
allow: reasonable mixtures, e.g. C7H16 + C3H6 [1]
(b) refinery gas: (fuel) for heating / (fuel) for cars / (fuel) for cooking; [1]
gasoline: (fuel) for cars / mowers etc.; [1]
(c) unsaturated: contains double bonds / contains C=C bonds; [1]

hydrocarbon: containing carbon and hydrogen only; [1]
(d) (i) 1st box down ticked (catalytic addition of steam) [1]
(ii) correct structure of ethanol; [1]

bond between O-H; [1]
(e) monomers; [1]

polymers; [1]
© UCLES 2017 0620/03/SM/20

Cambridge IGCSE®
CHEMISTRY 0620/04
*0123456789*
Paper 4 Theory (Extended) For examination from 2020

SPECIMEN PAPER
1 hour 15 minutes


2
1 The following table gives information about six substances.
melting point boiling point electrical conductivity electrical conductivity

substance
/ °C / °C as a solid as a liquid
A 839 1484 good good
B –188 –42 poor poor
C 776 1497 poor good
D –117 78 poor poor
E 1607 2227 poor poor
F –5 102 poor good
(a) Which substance could be a metal?
[1]
(b) State all the substances that are liquid at room temperature.
[1]
(c) Which substance could have a macromolecular structure similar to that of silicon(IV) oxide?
[1]
(d) Which substance could be propane?
[1]
(e) Which substance could be sodium chloride?
[1]
[Total: 5]
© UCLES 2017 0620/04/SP/20

3
2 The table gives the composition of three particles.

particle
A 15 15 16
B 15 18 16
C 15 15 17
(a) What is the evidence in the table for each of the following?
(i) Particle A is an atom.
[1]
(ii) A, B and C are all particles of the same element.
[1]
(iii) Particles A and C are isotopes of the same element.
[2]
(b) (i) What is the electronic structure of particle A?
[1]
(ii) Is element A, a metal or a non-metal? Give a reason for your choice.
[1]
[Total: 6]

4
3 Kinetic theory explains the properties of matter in terms of the arrangement and movement of
particles.
(a) Nitrogen is a gas at room temperature. Nitrogen molecules, N2, are spread far apart and
move in a random manner at high speed.
(i) Draw the electronic structure of a nitrogen molecule.

[2]
(ii) Compare the movement and arrangement of the molecules in solid nitrogen to those in
nitrogen gas.
[3]
(b) A sealed container contains nitrogen gas. The pressure of the gas is due to the molecules of
the gas hitting the walls of the container.
Use the kinetic theory to explain why the pressure inside the container increases when the
temperature is increased.
[2]
© UCLES 2017 0620/04/SP/20

5
The following apparatus can be used to measure the rate of diffusion of a gas.
constant
pressure
applied metal foil,
gas escapes
gas syringe gas through small
hole in foil
The following results were obtained.
temperature rate of diffusion

gas
/ °C in cm3 / min
nitrogen 25 1.00
chlorine 25 0.63
nitrogen 50 1.05
(c) (i) Explain why nitrogen gas diffuses faster than chlorine gas.
[2]
(ii) Explain why the nitrogen gas diffuses faster at the higher temperature.
[1]
[Total: 10]

6
4 Chromium is a transition element.
(a) (i) State two differences in the physical properties of chromium and sodium.
[2]
(ii) State two differences in the chemical properties of chromium and sodium.
[2]
(b) Chromium is used to electroplate steel objects. The diagram shows how this could be done.
+ –
lead anode object to

be plated
chromium(III)
sulfate(aq)
(i) Give two reasons why steel objects are plated with chromium.
[2]
(ii) The formula of the chromium(III) ion is Cr3+ and of the sulfate ion is SO42–. Give the
formula of chromium(III) sulfate.
[1]
(iii) Write the ionic half-equation for the reaction at the negative electrode (cathode).
[2]
(iv) A colourless gas, which relights a glowing splint, is formed at the positive electrode
(anode).
[1]
© UCLES 2017 0620/04/SP/20

7
(v) During electroplating, it is necessary to add more chromium(III) sulfate but during
copper plating using a copper anode, it is not necessary to add more copper(II) sulfate.
Explain this difference.
[2]
[Total: 12]

8
5 Iron is extracted from its ore, hematite, in the blast furnace.
waste gases
raw materials::
coke, C
iron ore, Fe2O3
firebrick lining limestone, CaCO3
air
slag
molten iron
Describe the reactions involved in this extraction.
Include one equation for a redox reaction and one for an acid/base reaction.
[5]
[Total: 5]
© UCLES 2017 0620/04/SP/20

9
BLANK PAGE

10
6 Soluble salts can be made using a base and an acid.
(a) Complete this method of preparing dry crystals of the soluble salt
cobalt(II) chloride-6-water from the insoluble base cobalt(II) carbonate.
step 1
Add an excess of cobalt(II) carbonate to hot dilute hydrochloric acid.
step 2
step 3
step 4
[4]
© UCLES 2017 0620/04/SP/20

11
(b) (i) 5.95 g of cobalt(II) carbonate were added to 40 cm3 of hydrochloric acid, concentration
2.0 mol / dm3.
Calculate the maximum yield of cobalt(II) chloride-6-water and show that the cobalt(II)
carbonate was in excess.
CoCO3 + 2HCl → CoCl2 + CO2 + H2O
CoCl2 + 6H2O → CoCl2.6H2O
maximum yield:
number of moles of HCl used = ««««««««««««««««««...«..««.
number of moles of CoCl2 formed = «««««««««««««««««..«.««
number of moles of CoCl2.6H2O formed = «««««««««««««««..«..«
mass of one mole of CoCl2.6H2O = 238 g
maximum yield of CoCl2.6H2O = «««««««««««««««««««..«..« g
to show that cobalt(II) carbonate is in excess:
number of moles of HCl used = «««««««««.««« (use your value from above)
mass of one mole of CoCO3 = 119 g
number of moles of CoCO3 in 5.95 g of cobalt(II) carbonate = «««««««««« [5]
(ii) Explain how these calculations show that cobalt(II) carbonate is in excess.
[1]
[Total: 10]

12
7 Iodine reacts with chlorine to form dark brown iodine monochloride.
I2 + Cl2 → 2ICl
This reacts with more chlorine to give yellow iodine trichloride.

An equilibrium forms between these iodine chlorides.
ICl(l) + Cl2(g) ⇌ ICl3(s)

dark brown yellow
(a) What do you understand by the term equilibrium?
[2]
(b) When the equilibrium mixture is heated, it becomes a darker brown colour.
Suggest if the reverse reaction is endothermic or exothermic. Give a reason for your choice.
[1]
(c) The pressure on the equilibrium mixture is decreased.
(i) How would this affect the position of equilibrium? Give a reason for your choice.
It would move to the
reason
[1]
(ii) Describe what you would observe.
[1]
© UCLES 2017 0620/04/SP/20

13
(d) Calculate the overall energy change for the reaction between iodine and chlorine using the
bond energy values shown.
I2 + Cl2 → 2ICl
Bond Energy / kJ per mol
I–I 151
Cl – Cl 242
I – Cl 208
Show your working.
[3]
(e) Draw a labelled energy level diagram for the reaction between iodine and chlorine using the
information in (d).
[2]
[Total: 10]

14
8 The alcohols form an homologous series.
(a) Give three characteristics of an homologous series.
[3]
(b) The following two alcohols are members of an homologous series and they are isomers.
CH3 ― CH2 ― CH2 ― CH2 ― OH and (CH3)2CH ― CH2 ― OH
(i) Explain why they are isomers.
[2]
(ii) Deduce the structural formula of another alcohol which is also an isomer of these
alcohols.
[1]
© UCLES 2017 0620/04/SP/20

15
(c) Copper(II) oxide can oxidise butanol to liquid X, whose pH is 4.
mineral wool
soaked in butanol copper(II) oxide
heat
liquid X
formed by
oxidation of
butanol.
(i) Give the name of another reagent which can oxidise butanol.
[1]
(ii) Which homologous series does liquid X belong to?
[1]
(iii) State the formula of liquid X.
[1]

16
(d) The alcohol ethanol can be made by fermentation. Yeast is added to aqueous glucose.
C6H12O6(aq) → 2C2H5OH(aq) + 2CO2(g)
Carbon dioxide is given off and the mixture becomes warm, as the reaction is exothermic.
The graph shows how the rate of reaction varies over several days.
rate of
reaction
time
(i) Suggest a method of measuring the rate of this reaction.
[2]
(ii) Why does the rate initially increase?
[1]
(iii) Suggest two reasons why the rate eventually decreases.
[2]
[Total: 14]
© UCLES 2017 0620/04/SP/20

17
BLANK PAGE

18
9 There are two types of polymerisation, addition and condensation.
(a) Explain the difference between these two types of polymerisation.
[2]
(b) Some plastics, formed by polymerisation, are non-biodegradable.
Describe two pollution problems that are caused by non-biodegradable plastics.
[2]
© UCLES 2017 0620/04/SP/20

19
(c) The polymer known as PVA is used in paints and adhesives. Its structural formula is shown
below.
―CH2―CH―CH2―CH―
│ │
OCOCH3 OCOCH3
[1]
(d) A condensation polymer can be made from the following monomers.
[3]
[Total: 8]
© UCLES 2017 0620/04/SP/20

20
© UCLES 2017 0620/04/SP/20

Cambridge IGCSE®
CHEMISTRY 0620/04
Paper 4 Theory (Extended) For examination from 2020
MARK SCHEME
Maximum Mark: 80
Specimen

2
not do not allow
avp any valid point
© UCLES 2017 0620/04/SM/20

3
1 (a) A [1]
(b) D and F note: both needed for mark [1]
(c) E [1]
(d) B [1]
(e) C [1]
2 (a) (i) same number of protons and electrons [1]
(ii) all have the same number of protons / same proton number / same atomic number [1]
(iii) same number of protons / same proton number / same atomic number; [1]
different number of neutrons / different nucleon number / different mass number; [1]
(b) (i) 2, 8, 5 [1]
(ii) non-metal because it accepts electrons / needs 3e to complete outer energy level /
because it is in Group V or 5e in outer shell [1]
note: need both non-metal and reason for one mark
3 (a) (i) 6e between two nitrogen atoms; note: can be any combination of dots or crosses [1]
1 lone pair on each nitrogen atom; [1]
(ii) solid gas
pattern: regular / lattice random / irregular / no pattern; [1]
distance: close far apart / spread out; [1]
movement: vibrate / fixed position moving; [1]
(b) particles have more energy / move faster; [1]

collide harder / collide more frequently / more collisions / collide with more force; [1]
allow: molecules instead of particles
(c) (i) nitrogen has smaller Mr; [1]

nitrogen (molecules) move faster (than chlorine molecules) / ora; [1]
(ii) (at higher temperature) molecules move faster / have more energy [1]
© UCLES 2017 0620/04/SM/20

4
4 (a) (i) Any two from:

chromium
is harder;
has higher density;
has higher melting point / boiling point;
stronger;
ora; [2]
(ii) Any two from:

sodium is more reactive;
chromium has more than one oxidation state, sodium has one;
chromium forms coloured compounds, sodium compounds are white;
sodium reacts with cold water, chromium does not;
chromium forms complex ions, sodium does not;
chromium has catalytic properties, sodium does not; [2]
note: difference must be clear
(b) (i) Any two from:

appearance / shiny / more attractive / decoration;
resists corrosion / resists rusting;
hard surface; [2]
(ii) Cr2(SO4)3 [1]

ignore: correct charges on ions
(iii) Cr3+ + 3e → Cr [2]

note: one mark for equation and one mark for correct balancing
(iv) oxygen / O2 [1]
(v) to replace chromium ions (used to plate steel) / chromium ions used up; [1]
copper ions replaced from copper anode; [1]
5 one redox equation from: [1]

Fe2O3 + 3CO → 2Fe + 3CO2
2Fe2O3 + 3C → 4Fe + 3CO2
Fe2O3 + 3C → 2Fe + 3CO
C + O2 → CO2
CO2 + C → 2CO
one acid/base equation: [1]

CaO + SiO2 → CaSiO3
CaCO3 + SiO2 → CaSiO3 + CO2
Any three additional equations or comments from: [3]

carbon burns or reacts to form carbon dioxide;
this reaction is exothermic or produces heat;
carbon dioxide is reduced to carbon monoxide;
carbon monoxide reduces hematite to iron;
carbon reduces hematite to iron;
limestone removes silica to form slag;
limestone decomposes;
© UCLES 2017 0620/04/SM/20

5
6 (a) filter / centrifuge / decant; [1]

(partially) evaporate / heat / boil; [1]
allow to crystallise / cool / let crystals form; [1]
dry crystals / dry between filter paper / leave in a warm place to dry; [1]
(b) (i) number of moles of HCl used = 0.04 × 2 = 0.08; [1]

number of moles CoCl2 formed = 0.04; [1]
number of moles CoCl2.6H2O formed = 0.04; [1]
maximum yield of CoCl2.6H2O = 9.52; [1]
allow: 9.5
allow: ecf on number of moles of HCl
number of moles of HCl used = 0.08 note: must use their value
allow: ecf
number of moles of CoCO3 in 5.95 g of cobalt(II) carbonate = 5.95/119 = 0.05; [1]
(ii) 0.05 > 0.04 or stated in words;

allow: ecf on number of moles of CoCl2 formed [1]
7 (a) rates equal; [1]

concentrations do not change / macroscopic properties remain constant; [1]
(b) endothermic and because this direction is favoured by high temperatures; [1]
(c) (i) move to left hand side / reactants favoured and because bigger volume / more moles on
left hand side [1]
(ii) less (yellow) solid / more (dark brown) liquid / green gas visible / turns darker brown /
smell chlorine [1]
allow: ecf from (c)(i)
(d) (bond breaking =) 151 + 242 = 393; [1]

(bond making =) 208 × 2 = –416; not: 416 [1]
(overall =) 393 – 416 = –23; allow: ecf [1]
note: sign must be given
(e) Any two from:

diagram shows exothermic reaction;
activation energy shown;
reactants and products labelled / both axes labelled;
note: labelling is one mark only
allow: ecf from (d) [2]
© UCLES 2017 0620/04/SM/20

6
8 (a) Any three from:

similar chemical properties;
same functional group;
physical properties vary in a predictable way / give trend such as mp increases with n; [3]
(b) (i) they have the same molecular formula; [1]

not: general formula
different structures / structural formulae; [1]
(ii) CH3-CH2-CH(OH)-CH3 / (CH3)3C-OH [1]

allow: butan-2-ol and 2-methylpropan-2-ol
(c) (i) (acidified) potassium manganate(VII) [1]

allow: oxygen / air / (acidified) potassium chromate(VI)
(ii) carboxylic acid [1]

allow: aldehyde / ketone
(iii) CH3-CH2-CH2-COOH / C3H7COOH / C4H8O2 [1]

allow: C4H7OOH
allow: ecf on (c)(ii)
(d) (i) measure volume of gas; [1]

measure time; [1]
(ii) increase in temperature / more yeast present / yeast multiplies [1]
(iii) glucose used up; [1]

concentration of ethanol high enough to kill yeast; [1]
9 (a) addition: polymer is the only product / only one product; [1]
condensation: polymer and water formed / small molecule formed; [1]
(b) Any two from:

ingestion can be fatal to animals / owtte;
animals can be caught in plastics e.g. fishing line / owtte;
combustion releases toxins / owtte;
land-fill uses natural resources / owtte;
allow: any appropriate example [2]
(c) CH2=CHOCOCH3 [1]

note: double bond does not need to be shown
amide linkage correct; [1]
correct repeat units; [1]
continuation bonds shown; [1]
© UCLES 2017 0620/04/SM/20

Cambridge IGCSE®
CHEMISTRY 0620/05
*0123456789*
Paper 5 Practical Test For examination from 2020

SPECIMEN PAPER
1 hour 15 minutes
Additional materials: As listed in the confidential instructions


2
1 You are going to investigate the reaction between excess magnesium and two different dilute
acids, X and Y.
Instructions
(a) Experiment 1
Set up the apparatus as shown in the diagram below.

clamp
bung
inverted 100 cm3
measuring cylinder
conical flask
water
trough
Remove the bung from the conical flask and move the measuring cylinder away from the
delivery tube without letting any water run out. Twist one of the strips of magnesium to break
it into four pieces and place all four pieces into the conical flask.
Using a different measuring cylinder, measure 50 cm3 of dilute acid X. Pour it into the conical
flask and replace the bung firmly. Place the measuring cylinder back over the delivery tube
and start the timer. In the table, record the volume of gas collected in the measuring cylinder
time / s 0 30 60 90 120 150 180
volume of gas / cm3

[2]
(b) Experiment 2
Repeat the whole of Experiment 1 using 50 cm3 of dilute acid Y.

In the table, record the volume of gas collected in the measuring cylinder every 30 seconds
for three minutes.
time / s 0 30 60 90 120 150 180
volume of gas / cm3

[2]
© UCLES 2017 0620/05/SP/20

3
(c) Plot the results you have obtained for both experiments on the grid below. For each set of
results, draw a smooth line graph. Indicate clearly which line represents Experiment 1 and
which line represents Experiment 2.
[4]
this experiment.
[1]
[1]

4
rate =
time taken / s
rate [2]
(g) A student suggested that the magnesium should be rubbed with sandpaper before starting
the experiment. Explain why the magnesium should be rubbed with sandpaper.
[2]
(h) Give one advantage and one disadvantage of using a measuring cylinder to add the acids to
the flask.
advantage
disadvantage [2]
(i) Suggest and explain one improvement to this experiment.
[1]
[Total: 17]
© UCLES 2017 0620/05/SP/20

5
BLANK PAGE

6
2 You are provided with a mixture of two solids, C and D. Solid C is water-soluble and D is
insoluble in water. Carry out the following tests on C and D, recording all of your observations at
each stage.
Add 15 cm3 of distilled water to the mixture in the boiling tube. Stopper and shake the boiling tube
for two minutes. Filter the contents of the tube, keeping the filtrate and residue for the following
tests.
(a) (i) To about 1 cm3 of the solution, add a few drops of aqueous sodium hydroxide.
observation [1]
(ii) Now add excess aqueous sodium hydroxide to the mixture.
observation [1]
(b) To about 1 cm3 of the solution add an equal volume of aqueous ammonia.
observation [1]
(c) To about 1 cm3 of the solution add excess aqueous sodium hydroxide.
Now add a small piece of aluminium foil and warm the mixture carefully. Test any gases
given off.
observation
[2]
(d) Identify solid C.
[2]
Wash the residue in the filter paper with a little distilled water.
Using a spatula, transfer some of the solid residue from the filter paper into two test-tubes.
(e) Heat the solid in the first test-tube gently and then strongly. Leave the test-tube to cool.
observation
[2]
© UCLES 2017 0620/05/SP/20

7
(f) (i) Add about 2 cm3 of dilute hydrochloric acid to the second test-tube. Test any gases given
off. Keep this liquid for (f)(ii).
observation
[2]
(ii) After two minutes, add an equal volume of distilled water and shake the test-tube.
Decant off the liquid and divide the liquid into two approximately equal portions.
To the first portion add aqueous sodium hydroxide a little at a time until in excess.
observation
[2]
(iii) To the second portion add aqueous ammonia a little at a time until in excess.
observation
[2]
(g) Identify solid D.
[2]
[Total: 17]

8
test
result [2]

[4]
[Total: 6]
© UCLES 2017 0620/05/SP/20

9

Test for anions

produced


colourless
colourless solution
© UCLES 2017 0620/05/SP/20

10
sulfur dioxide (SO2) turns acidified aqueous potassium

colourless
© UCLES 2017 0620/05/SP/20

Cambridge IGCSE®
CHEMISTRY 0620/05
Paper 5 Practical Test For examination from 2020
MARK SCHEME
Maximum Mark: 40
Specimen

2
not do not allow
avp any valid point
© UCLES 2017 0620/05/SM/20

3
1 (a) volume, at time = 0 given; [1]

(b) volume, at time = 0 given; [1]

(e) value from graph to ± half a small square accuracy and indication shown on graph [1]
(f) correct calculation of rate; [1]

allow: ecf on (d)
cm3 / s / cm3 s–1 / cm3 per s; [1]
allow: sec
(g) Any two from:

magnesium has an oxide coating;
rubbing exposes magnesium to the acid / removes oxide coating;
gives true rate / owtte; [2]
(h) advantage: convenient / easy / quick to use; [1]

(i) graduated pipette / burette / gas syringe / mass of magnesium rather than strips / repeats
(ii) no change / precipitate remains [1]
(b) no precipitate / slight (white) precipitate [1]
© UCLES 2017 0620/05/SM/20

4
(c) Any two from:

effervescence / fizz / bubbles;
(damp) pH paper blue / purple;
ammonia smell; [2]
(d) calcium; [1]

nitrate; [1]
(e) yellow / brown / orange colour when hot; [1]

colour fades / goes white when cool; [1]
(f) (i) effervescence / bubbles / fizz; [1]

limewater turns milky; [1]
(ii) white precipitate; [1]


(g) zinc; [1]

allow: aluminium dependent on (f)(iii)
carbonate; [1]

(b) Any four from:

chromatography;
use of solvent;
note: marks can be obtained from a labelled diagram
© UCLES 2017 0620/05/SM/20

Cambridge IGCSE®
CHEMISTRY 0620/06
*0123456789*
Paper 6 Alternative to Practical For examination from 2020

SPECIMEN PAPER
1 hour


2
1 The diagram shows the apparatus used to prepare a dry sample of a gas. The gas is more dense
than air.
stand and
clamp
concentrated
sulfuric acid
(b) Identify one mistake in the apparatus.
[1]
(c) Suggest a reason why the gas is passed through concentrated sulfuric acid.
[1]
[Total: 5]
© UCLES 2017 0620/06/SP/20

3
2 A student investigated the rate of reaction between excess magnesium and two different dilute
acids, X and Y.
Experiment 1

clamp
inverted
bung 100 cm3
measuring
cylinder
conical flask
trough water
Using a measuring cylinder, 50 cm3 of dilute acid X was poured into the conical flask.
0.5 g of magnesium ribbon was added to the conical flask and the bung added.
The timer was started and the volume of gas collected in the measuring cylinder was measured

4
(a) Use the measuring cylinder diagrams to record the volumes of gas collected.

time / s
0
0 5
10
10
30 15
20
20
60 25
30
25
90 30
35
30
120 35
40
40
150 45
50
45
180 50
55
[2]
© UCLES 2017 0620/06/SP/20

5
Experiment 2
Experiment 1 was repeated using 50 cm3 of dilute acid Y.
(b) Use the measuring cylinder diagrams to record the volumes of gas collected.

time / s
0
0 5
10
0
30 5
10
5
60 10
15
10
90 15
20
10
120 15
20
15
150 20
25
15
180 20
25
[2]

6
(c) Plot the results for both experiments on the grid below. For each set of results, draw a
smooth line graph. Indicate clearly which line represents Experiment 1 and which line
represents Experiment 2.
[4]
this experiment.
[1]
[1]
© UCLES 2017 0620/06/SP/20

7
rate =
time taken / s
rate [2]
(g) Give one advantage and one disadvantage of using a measuring cylinder to add the acids to
the flask.
advantage
disadvantage [2]
(h) Suggest and explain one improvement to this experiment.
[1]
[Total: 15]

8
3 Concentrated aqueous sodium chloride was broken down by electricity using the apparatus
shown.
gas A gas B
concentrated aqueous
sodium chloride
electrodes
+ –
(a) Suggest a suitable material from which to make the electrodes.
[1]
(b) Gas A is chlorine. Give a test for chlorine.
test
result [2]
(c) Gas B pops when tested with a lighted splint. What is gas B?
[1]
[Total: 4]
© UCLES 2017 0620/06/SP/20

9
BLANK PAGE

10
4 Solid E was analysed. E was an aluminium salt. Some of the observations are shown below.
Appearance of solid E. white crystalline solid
test 1
colourless drops of liquid formed at the top of
the tube
A little of solid E was heated in a test-tube.
(a) A little of solid E was dissolved in distilled water.
The solution was divided into four test-tubes and the following tests were carried out.
Complete the observations for tests 2 and 3.
(i) test 2
Drops of aqueous sodium hydroxide were added to the first test-tube.
observations [1]
(ii) Excess sodium hydroxide was then added.
observations [1]
(iii) test 3
Drops of aqueous ammonia solution were added to the second test-tube. Excess
ammonia solution was then added.
observations
[2]
Two further tests are carried out and the following observations made.
tests on solution of E observations
test 4
To the third test-tube of solution, dilute no reaction

hydrochloric acid was added, followed by
barium nitrate solution.
test 5
effervescence
To the fourth test-tube of solution, aqueous
sodium hydroxide and aluminium foil were pungent gas given off
added.
gas turned damp litmus paper blue
The mixture was warmed carefully.
© UCLES 2017 0620/06/SP/20

11
(b) What does test 1 tell you about solid E?
[1]
(c) Identify the gas given off in test 5.
[1]
(d) What conclusions can you draw about solid E?
[2]
(e) Test 5 states that the mixture should be warmed carefully.
In terms of safety, explain why it is necessary to warm carefully.
[2]
[Total: 10]

12
test
result [2]

[4]
[Total: 6]
© UCLES 2017 0620/06/SP/20

Cambridge IGCSE®
CHEMISTRY 0620/06
Paper 6 Alternative to Practical For examination from 2020
MARK SCHEME
Maximum Mark: 40
Specimen

2
not do not allow
avp any valid point
© UCLES 2017 0620/06/SM/20

3
1 (a) tap / separating / dropping funnel; [1]

not: burette
delivery tube; [1]
gas jar; [1]
allow: measuring cylinder
(b) gas should be collected downwards / owtte [1]
(c) to remove water / to remove impurities [1]
2 (a) volume boxes completed correctly 0, 13, 22, 30, 36, 43, 49
(b) volume boxes completed correctly 0, 5, 10, 13, 17, 20, 23

(e) 71–73 s and indication shown on graph; [1]

allow: ecf from incorrect graph
(f) 13 ÷ 30 = 0.43; [1]

allow: 0.4
allow: ecf on plotting
cm3 / s / cm3 s–1 / cm3 per s; [1]
allow: sec
(g) advantage: convenient / easy / quick to use; [1]

(h) graduated pipette / burette / gas syringe / mass of magnesium rather than strips / repeats
© UCLES 2017 0620/06/SM/20

4
3 (a) platinum / graphite / carbon [1]
(b) damp blue litmus paper / Universal indicator paper / pH paper; [1]
bleaches / turns white; [1]
(c) hydrogen [1]
(ii) precipitate dissolves in excess; [1]

no change / precipitate remains; [1]
(b) contains water / hydrated [1]
(c) ammonia
not: ammonium [1]
(d) Any two from:

nitrate;
hydrated salt / contains water;
it is not a sulfate; [2]
(e) sodium hydroxide is hazardous / irritant / caustic; [1]

allow: toxic
boiling causes mixture to spit / blow-out; [1]

(b) Any four from:

chromatography;
use of solvent;
marks can be obtained from a labelled diagram
© UCLES 2017 0620/06/SM/20

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
International General Certificate of Secondary Education
CHEMISTRY 0620/11
Paper 1 Multiple Choice May/June 2011
45 Minutes
Soft clean eraser
*9373386046*

Do not use staples, paper clips, highlighters, glue or correction fluid.
You may use a calculator.
IB11 06_0620_11/2RP
2

D The substance in stage 3 has a fixed volume.
2 An aqueous solution is coloured.
Which method of separation would show that the solution contains ions of different colours?
A chromatography
B crystallisation
C distillation
D filtration
3 The table gives the solubility of four substances in ethanol and in water.
A mixture containing all four substances is added to ethanol, stirred and filtered.
The solid residue is added to water, stirred and filtered.
The filtrate is evaporated to dryness, leaving a white solid.
Which is the white solid?
solubility in
ethanol water
A insoluble insoluble
B insoluble soluble
C soluble insoluble
D soluble soluble
© UCLES 2011 0620/11/M/J/11

3
W 2,4
X 2,8
Y 2,8,1
Z 2,8,7
A W and X B X and Y C Y and Z D Z and W
5 The diagram shows part of the Periodic Table.
A B
C D
Which element is correctly matched with its electronic structure?
electronic structure
A 2,8,1
B 2,4
C 2,8,2
D 2,8
6 In the diagrams, circles of different sizes represent atoms of different elements.
Which diagram represents hydrogen chloride gas?
A B C D
© UCLES 2011 0620/11/M/J/11 [Turn over

4
7 The nucleon number and proton number of the lithium atom are shown by the symbol 73 Li .
6
A 2 Li− B 6
3 Li+ C 7
3 Li+ D 7
3 Li−
8 What is the relative molecular mass (Mr) of HNO3?
A 5 B 31 C 32 D 63
9 Electricity from a power station passes through overhead cables to a substation and then to a
school where it is used to electrolyse concentrated hydrochloric acid using inert electrodes.
Which substances are used for the overhead cables and for the electrodes?
overhead cables electrodes
A aluminium copper
B aluminium platinum
C copper platinum
D platinum aluminium
10 Which statement about the electrolysis of molten lead(II) bromide is correct?
A A colourless gas is seen at the cathode.

B A grey metal is seen at the anode.
C A red / brown gas is seen at the anode.
D A red / brown metal is seen at the cathode.
© UCLES 2011 0620/11/M/J/11

5
11 Electricity is passed through concentrated aqueous sodium chloride, as shown.
positive negative
+ –
electrode carbon electrode
rods
concentrated
aqueous sodium
chloride
What is the test for the gas formed at the positive electrode?
A bleaches damp litmus paper

B ‘pops’ with a lighted splint
C relights a glowing splint
D turns damp red litmus paper blue
12 Three processes are listed.
burning methane in air

radioactive decay of 235U
reacting hydrogen with oxygen.
Which statements about these processes are correct?
1 Hydrogen and methane are being used as fuels.

2 All the processes involve oxidation.
3 All the processes are used to produce energy.
A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

6
13 Butane, ethanol and hydrogen are fuels.
Which substances produce both carbon dioxide and water when used as a fuel?
butane ethanol hydrogen
A
B
C
D
14 The equation for the effect of heat on hydrated sodium carbonate is as shown.
Na2CO3.10H2O(s) Na2CO3(s) + 10H2O(g)
Statements made by four students about the reaction are given.
P Anhydrous sodium carbonate is formed.

Q Steam is formed.
R There is a colour change from blue to white.
S The reaction is reversible.
Which students’ statements are correct?
A P, Q and R only
B P, Q and S only
C Q, R and S only
D P, Q, R and S
© UCLES 2011 0620/11/M/J/11

7
gas syringe
For which two reactions would the apparatus be suitable?
reaction 1 AgNO3(aq) + HCl (aq) → AgCl (s) + HNO3(aq)
reaction 2 2H2O2(aq) → 2H2O(l) + O2(g)
reaction 3 MgO(s) + 2HCl (aq) → MgCl 2(aq) + H2O(l)
reaction 4 ZnCO3(s) + 2HCl (aq) → ZnCl 2(aq) + CO2(g) + H2O(l)
R
volume of S
hydrogen
given off
time

8
17 Carbon dioxide is an acidic oxide that reacts with aqueous calcium hydroxide.
A decomposition
B fermentation
C neutralisation
D oxidation
18 Which is not a typical property of an acid?
A They react with alkalis producing water.

B They react with all metals producing hydrogen.
C They react with carbonates producing carbon dioxide.
D They turn litmus paper red.
19 A solution contains barium ions and silver ions.
A chloride only
B nitrate only
C sulfate only
test result



© UCLES 2011 0620/11/M/J/11

9
gas X
Which statement about X is correct?
A X burns in air.
B X is coloured.
C X is unreactive.
22 The diagram shows a section of the Periodic Table.
I II III IV V VI VII 0
V W X
Y Z
Which elements will conduct electricity at room temperature?
A V, W and X B V, Y and W C W, X and Z D Y and Z
23 The equation shows the reaction between a halogen and aqueous bromide ions.
X2 + 2Br–(aq) → 2X–(aq) + Br2

…1… …2… …3…
Which words correctly complete gaps 1, 2 and 3?
1 2 3
A chlorine brown colourless

B chlorine colourless brown
C iodine brown colourless
D iodine colourless brown

10
24 Which statement is correct for the element of proton number 19?
A It is a gas that dissolves in water.

B It is a hard metal that is not very reactive with water.
C It is a non-metal that burns quickly in air.
D It is a soft metal that is highly reactive with water.
25 Brass is an alloy of copper and zinc.
Which statement is correct?
A Brass can be represented by a chemical formula.

B Brass is formed by a chemical reaction between copper and zinc.
C The alloy will dissolve completely in dilute hydrochloric acid.
D The zinc in the alloy will dissolve in dilute hydrochloric acid.
26 Which substance is a metal?
electrical conductivity electrical conductivity

(solid) (molten)
A high high
B high low
C low high
D low low
water.

A P R Q
B P Q R
C R Q P
D R P Q
© UCLES 2011 0620/11/M/J/11

11
28 The properties of a metal are important in deciding its use.
Which row lists a property that is not correct for the use given?
use of the metal metal property needed
A aluminium in aircraft wings low density

B aluminium in food containers resists corrosion
C mild steel in car bodies high density
D stainless steel in cutlery does not rust
29 Which row describes the conditions used to make steel from the iron produced by a blast
furnace?
calcium oxide
oxygen heat
(lime)
A
B
C
D
30 Water from a reservoir flows to the water works where purification processes 1 takes place
followed by process 2.
What are purification processes 1 and 2?
purification purification
process 1 process 2
A chlorination filtration
B filtration chlorination
C fractional distillation filtration
D filtration fractional distillation

12
31 The diagram shows the composition by volume of air.
What is X?
A argon
B carbon dioxide
C nitrogen
D oxygen

A W only
B W, X and Z
C W and Y only
D W, Y and Z
© UCLES 2011 0620/11/M/J/11

13
33 Statement 1: Alloying iron with other materials to form stainless steel prevents iron from rusting
by excluding oxygen.
Statement 2: Painting, oiling and electroplating are all methods of preventing iron from rusting.
Which is correct?
A Both statements are correct and statement 2 explains statement 1.

B Both statements are correct but statement 2 does not explain statement 1.
C Statement 1 is correct but statement 2 is incorrect.
D Statement 2 is correct but statement 1 is incorrect.
34 Which two substances, when reacted together, would form a salt that contains two of the
essential elements provided by fertilisers?
A potassium hydroxide and nitric acid

B potassium hydroxide and sulfuric acid
C sodium hydroxide and nitric acid
D sodium hydroxide and sulfuric acid
Gas ……1…… is produced by process ……3…… .

Gas ……2…… is produced by process ……4…… .
Which words correctly complete gaps 1, 2, 3 and 4?
1 2 3 4


14
36 Compounds containing five carbon atoms in a molecule may have names beginning with ‘pent…’.
What is the name of the compound shown?
key
= carbon
= oxygen
= hydrogen
A pentane
B pentanoic acid
C pentanol
D pentene
37 Which industrial process is shown in the diagram?
waste
gases
petrol
paraffin
diesel
crude lubricating
oil vapour oils
bitumen
A cracking
B fermentation
C fractional distillation
D polymerisation
© UCLES 2011 0620/11/M/J/11

15
38 The diagram shows the structures of three compounds.
O H O O H H
H C H H C C H H C C C H
H H H
Why do these three compounds belong to the same homologous series?
A They all contain carbon, hydrogen and oxygen.

C They are all carbon based molecules.
D They are all flammable liquids.
39 What is the main constituent of natural gas?
A carbon dioxide
B ethane
C hydrogen
D methane
40 What is not essential for the formation of ethanol by fermentation?
A light
B sugar
C yeast
D water
© UCLES 2011 0620/11/M/J/11

© UCLES 2011
DATA SHEET
The Periodic Table of the Elements
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Tin Antimony Tellurium Xenon
0620/11/M/J/11
Indium Iodine
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Caesium Barium Lanthanum Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine Radon
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
Francium Radium Actinium
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
*58-71 Lanthanoid series
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
90-103 Actinoid series Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium
58 59 60 61 62 63 64 65 66 67 68 69 70 71
a a = relative atomic mass 232 238
Key X X = atomic symbol Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium
b b = proton (atomic) number 90 91 92 93 94 95 96 97 98 99 100 101 102 103
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of
MARK SCHEME for the May/June 2011 question paper

for the guidance of teachers
0620 CHEMISTRY
0620/11 Paper 1 (Multiple Choice), maximum raw mark 40
Mark schemes must be read in conjunction with the question papers and the report on the
examination.
• Cambridge will not enter into discussions or correspondence in connection with these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2011 question papers for most IGCSE,
GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level
syllabuses.
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
IGCSE – May/June 2011 0620 11
Question Question
Key Key
Number Number
1 D 21 C
2 A 22 B
3 B 23 B
4 C 24 D
5 C 25 D
6 A 26 A
7 C 27 A
8 D 28 C
9 B 29 A
10 C 30 B
11 A 31 C
12 B 32 D
13 B 33 D
14 B 34 A
15 C 35 D
16 B 36 C
17 C 37 C
18 B 38 B
19 B 39 D
20 B 40 A
© University of Cambridge International Examinations 2011

*4887369687*
CHEMISTRY 0620/21
Paper 2 May/June 2011
1 hour 15 minutes
Write your Centre number, candidate number and name in the spaces at the top of this page.
You may need to use a pencil for any diagrams, graphs or rough working.

For Examiner’s Use
1
The number of marks is given in brackets [ ] at the end of each question or part
question. 2
Total
IB11 06_0620_21/4RP
2
For
1 The structures of some substances containing nitrogen are shown below. Examiner’s
Use
A B C
K+ NO3– K+ Cl
N
H H NO3– K+ NO3–
N
H
+
K NO3 K – + Cl Cl
D E
N
N N
O O

(a) an acidic oxide,
(b) an ionic giant structure,
(c) a gas which turns moist litmus paper blue,
(d) a compound which is formed under conditions

(e) a molecule containing halogen atoms,
(f) a salt?
[Total: 6]
© UCLES 2011 0620/21/M/J/11

3
For
2 Vanadium has two isotopes. Examiner’s
Use
50 51
23 V 23 V
(a) Define the term isotope.
...........................................................................................................................................
..................................................................................................................................... [1]
(b) An atom contains protons, electrons and neutrons.

Complete the table to show the number of protons, electrons and neutrons in these two
isotopes of vanadium.

isotope
50
23 V 23 23
51
23 V 28
[3]
(c) Complete these sentences using words from the list.
cancer extra industry influenza medicine non
Two types of isotopes are radioactive and ..........................-radioactive. Radioactive
isotopes are used in .......................... for treating patients with .......................... . [3]
(d) Vanadium is a transition element.

Which two of these statements about vanadium are correct?
Tick two boxes.
vanadium is a non-metal
vanadium conducts electricity
vanadium has a low melting point
vanadium is less dense than sodium
compounds of vanadium are coloured
[2]
[Total: 9]

4
For
3 Water is present in the atmosphere, the seas and in ice and snow. Examiner’s
Use
(a) Describe a chemical test for water.
test ....................................................................................................................................
result ........................................................................................................................... [2]
(b) State one use of water in industry.
..................................................................................................................................... [1]
(c) Water is a good solvent.

What do you understand by the term solvent ?
..................................................................................................................................... [1]
(d) Water vapour in the atmosphere reacts with sulfur dioxide, SO2, to produce acid rain.
(i) State one source of sulfur dioxide.
.............................................................................................................................. [1]
(ii) State two adverse effects of acid rain.
1. ................................................................................................................................
2. .......................................................................................................................... [2]
(iii) Calculate the relative molecular mass of sulfur dioxide.
[1]
(e) Water from lakes and rivers can be treated to make the water safer to drink.
Describe two of the steps in water purification.

For each of these steps, give an explanation of its purpose.
step 1 ................................................................................................................................
...........................................................................................................................................
step 2 ................................................................................................................................
..................................................................................................................................... [4]
© UCLES 2011 0620/21/M/J/11

5
For
(f) Water is formed when hydrogen burns in air. Examiner’s
Use
(i) State the percentage of oxygen present in the air.
.............................................................................................................................. [1]
(ii) When 8 g of hydrogen is burned in excess air, 72 g of water is formed.

What mass of hydrogen needs to be burnt to produce 252 g of water?
[1]
[Total: 14]

6
For
4 The structures of some organic compounds are shown below. Examiner’s
Use
A B C
H H H H H H Br Br
H C C C H C C C H H C C H
H H H H H H H
D E
H H H H
C C H C C O H
H H n
H H
(a) Which one of these structures represents
(i) a polymer,
(ii) an unsaturated hydrocarbon,
(iii) the product of the catalytic addition of steam to ethene,
(iv) a product of the addition of aqueous bromine to ethene?

[4]
(b) (i) Balance the equation for the complete combustion of compound A, C3H8.
C3H8 + ............O2 → 3CO2 + ............H2O
[2]
(ii) State the name of two substances formed when compound A undergoes incomplete
combustion.
......................................................... and ......................................................... [2]
(c) Complete the structure of ethanoic acid to show all atoms and bonds.
H C
[1]
[Total: 9]
© UCLES 2011 0620/21/M/J/11

7
For
5 Concentrated hydrochloric acid can be electrolysed using the apparatus shown. Examiner’s
Use
concentrated
hydrochloric acid

+ –
(a) What do you understand by the term electrolysis ?
...........................................................................................................................................
..................................................................................................................................... [1]


[1]
..................................................................................................................................... [1]
Electrodes made of graphite or .......................... are generally used in electrolysis
because they are .......................... . [2]

8
For
(e) When concentrated hydrochloric acid is electrolysed, chlorine is released at the positive Examiner’s
electrode. Use
(i) Draw the arrangement of the electrons in an atom of chlorine.
[1]

[2]
test .............................................................................................................................
result .................................................................................................................... [2]
hydrochloric acid + calcium hydroxide → ............................. + .............................
.............................
[2]

Zn + ........HCl → ZnCl 2 + ........

[2]
[Total: 14]
© UCLES 2011 0620/21/M/J/11

9
For
6 A student observed the reaction of various metals with both cold water and steam. Her results Examiner’s
are shown below. Use
metal reaction with cold water reaction with steam
calcium reacts rapidly reacts very rapidly

copper no reaction no reaction
magnesium reacts very slowly reacts rapidly
zinc no reaction reacts
(a) (i) Put these metals in order of their reactivity.
least reactive most reactive
[1]
(ii) Iron is a metal between zinc and copper in the reactivity series.
Predict the reactivity of iron with
cold water, .................................................................................................................
steam. .................................................................................................................. [2]
(b) The equation for the reaction of zinc with steam is:
Zn + H2O → ZnO + H2
Write a word equation for this reaction.
[1]
(c) State three physical properties which are characteristic of most metals.
1. .......................................................................................................................................
2. .......................................................................................................................................
3. ................................................................................................................................. [3]

10
For
(d) Some properties of the Group I metals are shown in the table. Examiner’s
Use
melting point density

metal hardness
/ °C / g per cm3
lithium fairly hard 0.53

sodium 98 fairly soft
potassium 63 soft
rubidium 39 very soft 1.53
caesium 29 extremely soft 1.88
(i) Estimate the melting point of lithium.
.............................................................................................................................. [1]
(ii) How does the hardness of these metals change down the group?
.............................................................................................................................. [1]
(iii) Estimate the density of potassium.
.............................................................................................................................. [1]
[Total: 10]
© UCLES 2011 0620/21/M/J/11

11
For
7 The diagram shows a basic oxygen converter. This is used to convert impure iron from the Examiner’s
blast furnace into steel. During this process, some of the impurities in the iron are converted Use
into a slag.
(a) Label the diagram to show each of the following:
● where the oxygen enters;

● the slag;
● the molten steel. [3]
(b) In the converter, the oxygen oxidises sulfur, carbon and phosphorus to their oxides.
(i) Explain why sulfur dioxide and carbon dioxide are easily removed from the
converter.
.............................................................................................................................. [1]
(ii) Explain how calcium oxide is used to remove phosphorus(V) oxide from the
converter.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]

12
For
(c) Stainless steel is an alloy. Examiner’s
Use
(i) Which one of the diagrams, A, B, C or D, best represents an alloy?
A B C D
[1]
(ii) State one use of stainless steel.
.............................................................................................................................. [1]
[Total: 9]
© UCLES 2011 0620/21/M/J/11

13
For
8 Bromine is a red-brown liquid. When warmed, it forms an orange vapour. Examiner’s
Use
(a) Describe what happens to the arrangement and motion of the particles when bromine
changes state from a liquid to a vapour.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(b) Bromine can be obtained from bromide ions in seawater.
(i) The symbol equation for this reaction is:
Cl 2 + 2Br – → 2Cl – + Br2
Complete the word equation for this reaction.
...................... + bromide ions → ...................................... + ......................

[1]
(ii) Bromine is very volatile, so it can be removed from solution by bubbling air through
the solution.
What do you understand by the term volatile ?
.............................................................................................................................. [1]
(c) Hydrogen reacts with bromine in the presence of a hot platinum catalyst to form hydrogen
bromide.
(i) Define the term catalyst.
.............................................................................................................................. [1]
(ii) Hydrogen bromide reduces hydrogen peroxide, H2O2.
2HBr + H2O2 → Br2 + 2H2O
Explain how this equation shows that hydrogen peroxide is reduced.
....................................................................................................................................
.............................................................................................................................. [1]

14
For
(iii) A solution of hydrogen bromide in water is called hydrobromic acid. Examiner’s
Hydrobromic acid has similar reactions to hydrochloric acid. Use
State the names of three products formed when hydrobromic acid reacts with sodium
carbonate.
.............................................................................................................................. [2]
[Total: 9]
© UCLES 2011 0620/21/M/J/11

15
BLANK PAGE
© UCLES 2011 0620/21/M/J/11

© UCLES 2011
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/21/M/J/11
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included the

0620 CHEMISTRY
0620/21 Paper 2 (Core Theory), maximum raw mark 80
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of
the examination. It shows the basis on which Examiners were instructed to award marks. It does not
indicate the details of the discussions that took place at an Examiners’ meeting before marking began,
which would have considered the acceptability of alternative answers.
examination.
syllabuses.
(d) E / nitrogen(di)oxide / NO2 [1]
(e) C / NCl3 / nitrogen (tri)chloride [1]
2 (a) atoms of same element with different number of neutrons / same type of atom with different
mass number / atoms with same proton number but different number of neutrons / atoms
with same proton number but different nucleon number/ atoms with same atomic number but
different nucleon number [1]
(b) 23 protons [1]

23 electrons [1]
27 neutrons [1]
(c) non [1]

medicine [1]
cancer [1]
(d) 2nd box ticked [1]

5th box ticked [1]

3 (a) anhydrous copper sulfate / white copper sulfate [1]

ignore oxidation numbers
turns blue [1]
OR
anhydrous cobalt chloride / blue cobalt chloride (1 mark)

ignore oxidation numbers
turns pink (1 mark)
note second mark is dependent on the first being correct BUT cobalt chloride turns pink = 1
mark
(b) coolant / solvent / hydroelectric power [1]

allow for cooling / to cool
allow specific reactions e.g. making sulfuric acid / making ethanol
allow: for washing or cleaning if specific industrial process mentioned
allow for agriculture / for growing crops (on a large scale) / brewing
ignore for cooking / for drinking / for power (unqualified) / for watering plants / for cooling food
(c) substance OR liquid which dissolves another (substance) /

substance which does the dissolving [1]
ignore it dissolves / it is a liquid / names of solvents
(d) (i) burning coal / burning fossil fuels / burning petrol petrol / burning specified fuel (as long
as it contains sulfur) / from volcanoes / from heating sulphide ores [1]
ignore burning pure substances e.g. hydrogen, methane / car exhausts
ignore from ores without qualification /
(ii) any two effects (1 mark each) e.g. [2]

• forest death / kills trees / deforestation / destroys trees / damages trees
ignore kills plants / rots trees / kills crops
• acidification of lakes / acidification of rivers
ignore acidifies soils
• kills fish / aquatic plants / plant in lakes or rivers
ignore kills fish or plants in the sea / kills animal (unqualified) / kills plants
(unqualified)
• erodes buildings made from limestone / erodes carbonate rocks / damages buildings
made from limestone / damages carbonate rocks
allow destroys building made from limestone / destroys carbonate rocks
ignore just erosion of buildings or rocks unqualified / dissolves buildings / chemical
weathering
• corrosion of metal structures / corrosion of named metal structures e.g. bridges or
railings / damages metal structures
allow erosion of metal structures / damaging metal structures / destroys metal
structures / reacts with metals
ignore dissolves metals
ignore effects on humans
(iii) 64 (g) [1]

(e) In each of these points, the explanation mark depends on the correct step
filtration or words to that effect [1]
removal of undissolved substances / solids / impurities get trapped / removes insoluble

impurities [1]
allow removes dirt
ignore solids which would sediment rapidly or are large e.g. pieces of metal, batteries, twigs
etc. / removes impurities
chlorination / adding chlorine [1]

allow chlorification
kills bacteria [1]

allow kills microbes / kills germs / disinfection / sterilisation
ignore kills bugs / removes bacteria
allow other stages with correct explanation e.g.

screening (1 mark) removing large objects / removing twigs etc. (1 mark)
sedimentation (1 mark) allowing particles to settle (1 mark)
adding carbon (1 mark) removes tastes / removes smells (1 mark)
flocculation (1 mark) coagulates clay / makes small particles clump together (1 mark)
lime (1 mark) idea of neutralisation or removal of acids (1 mark)
(f) (i) 20 (%) allow 19–21 (%) [1]
(ii) 28 (g) [1]

4 (a) (i) D [1]
(ii) B [1]
(iii) E [1]
(iv) C [1]
(b) (i) 4 (H2O) [1]

5 (O2) [1]
note 2nd mark dependent on 4 (H2O) being correct
(ii) any 2 of:

carbon monoxide / carbon
allow soot
water
allow correct formulae [2]
(c)
O
║
-C–O–H [1]

5 (a) breakdown (of substance / electrolyte) by electricity / splitting up of substance by electricity /

allow current / voltage for electricity
ignore separation by electricity / division by electricity
note idea of breakdown AND idea of current / electricity for the mark
(b) anode [1]
(c) hydrogen [1]

allow H2
(d) platinum [1]

inert [1]
(e) (i) 2,8,7 as numbers or as shown in electron shell diagram [1]
(ii) pair of electrons between two chlorine atoms [1]

rest of electrons correct [1]
ignore inner shells
(iii) (damp) litmus (paper) / universal indicator (paper) [1]

allow indicator paper / pH paper
bleaches / goes white [1]

allow goes red then bleaches
reject changes colour of bromides / iodides

apply listing for extra elements / compounds
allow correct formulae
(ii) H2 on right [1]

ignore numbers in front of H2 unless equation balanced
2 on left [1]

6 (a) (i) copper → zinc → magnesium → calcium [1]
(ii) cold water → no reaction [1]

steam → fairly rapid / moderately rapidly / moderately / slowly / very slowly
ignore less rapidly than zinc / more rapidly that copper / it reacts [1]
reject rapidly
(b) zinc + water → zinc oxide + hydrogen [1]

allow steam in place of water
(c) Any three of: [3]

• conducts electricity
• conducts heat
• malleable / can be bent
• ductile /
• shiny / lustrous
• sonorous / rings when hit
• solid
ignore reference to melting point / boiling point / density / strength

ignore colours e.g. grey
(d) (i) allow any figures in the range 120–200°C [1]

(actual = 181°C)
(ii) less hard (down the Group) / softer (down the Group) [1]
allow decreases (in hardness)
ignore from hard to soft / the softer is at the bottom and the harder at the top / gets softer
as melting point decreases
(iii) allow any figures in the range 0.7–1.3 (g / cm3) [1]

(actual = 0.86)

7 (a) top left box → oxygen [1]

bottom right box → slag [1]
bottom left box → (molten) steel [1]
(b) (i) they are gases / gases escape easily / sulphur oxides are gases / named sulfur oxides
are gases / carbon dioxide is a gas / named oxide of carbon is gas / the products are
gases [1]
(ii) any three of:

• phosphorus(V) oxide is acidic oxide
ignore it is acidic
• calcium oxide is basic oxide
• idea of calcium oxide neutralising OR reacting with phosphorus oxide
allow they combine together / they react together / it reacts with the phosphorus
oxide
ignore they react (unqualified)
• slag formed (by the reaction) / slag is removed [3]
(c) (i) D [1]
(ii) any suitable use e.g. chemical plant / cutlery / surgical instruments / (ball) bearings / [1]
allow facings of buildings (not buildings without qualification)
parts of aircraft engines (not aircraft without qualification)
bridges
car decoration / trim / radiator grills / exhaust pipes (not cars without qualification)
washing machine drums
razor blades
chemical tankers / road tankers (not tankers unqualified)
cooking utensils ignore for cooking
watches

8 (a) any three of [3]

• particles move faster / in liquid particles move slowly AND in gas they move rapidly
• particles more spread out / in liquid particles are touching (or very close) AND in gas
they are far apart
• particles more randomly arranged / in liquid the particles have some order AND in gas
the particles are random
• particles move more freely / in liquid particles do not move freely AND in gases particles
are freely moving / in liquid particles have limited motion (or slide over each other) AND
in gases particles are free
(b) (i) chlorine + (bromide ions) → chloride (ions) + bromine [1]

allow correct symbols
(ii) vaporises easily / forms a gas easily [1]

allow vaporises (very) fast / evaporates (very) fast / low boiling point
reject ideas of reaction
(c) (i) substance which speeds up reaction / makes reaction go faster / lowers the activation
energy [1]
allow changes rate of reaction
ignore slows down reaction
(ii) it gains hydrogen / oxygen accepts hydrogen / hydrogen peroxide accepts hydrogen /
oxidation number of oxygen decreases [1]
allow it loses oxygen / hydrogen peroxide loses oxygen / hydrogen peroxide gains
electrons / oxygen gains electrons
ignore comments related to hydrogen bromide alone
(iii) sodium bromide [1]

carbon dioxide AND water [1]
[Total: 80]

*6145201818*
CHEMISTRY 0620/31
Paper 3 (Extended) May/June 2011
1 hour 15 minutes
You may use a pencil for any diagrams, graphs or rough working.

1
question. 2
Total
IB11 06_0620_31/4RP
2
For
1 The following techniques are used to separate mixtures. Examiner’s
Use
A simple distillation B fractional distillation C evaporation
D chromatography E filtration F diffusion
From this list, choose the most suitable technique to separate the following.
(a) methane from a mixture of the gases, methane and ethane .................. [1]
(b) water from aqueous magnesium sulfate .................. [1]
(c) glycine from a mixture of the amino acids, glycine and lysine ................... [1]
(d) iron filings from a mixture of iron filings and water .................. [1]
(e) zinc sulfate crystals from aqueous zinc sulfate .................. [1]
(f) hexane from a mixture of the liquids, hexane and octane .................. [1]
[Total: 6]
2 Selenium and sulfur are in Group VI. They have similar properties.
(a) One of the main uses of selenium is in photoelectric cells. These cells can change light
into electrical energy.
(i) Name a process which can change light into chemical energy.
....................................................................................................................................
(ii) Name a device which can change chemical energy into electrical energy.
.............................................................................................................................. [2]
(b) The electron distribution of a selenium atom is 2 + 8 + 18 + 6.
(i) Selenium forms an ionic compound with potassium. Draw a diagram which shows
the formula of this ionic compound, the charges on the ions and the arrangement of
the valency electrons around the negative ion.
Use o to represent an electron from an atom of potassium.
Use x to represent an electron from an atom of selenium.
[3]
© UCLES 2011 0620/31/M/J/11

3
For
(ii) Draw a diagram showing the arrangement of the valency electrons in one molecule Examiner’s
of the covalent compound selenium chloride. Use
Use x to represent an electron from an atom of selenium.
Use o to represent an electron from an atom of chlorine.
[3]
(iii) Predict two differences in the physical properties of these two compounds.
....................................................................................................................................
.............................................................................................................................. [2]
(c) The selenide ion reacts with water.
Se2– + H2O → HSe– + OH–
What type of reagent is the selenide ion in this reaction? Give a reason for your choice.
...........................................................................................................................................
..................................................................................................................................... [3]
[Total: 13]
3 Iron from the blast furnace is impure. It contains about 4 % carbon and 0.5 % silicon. Most
of this impure iron is used to make mild steel, an alloy of iron containing less then 0.25 %
carbon.
(a) A jet of oxygen is blown through the molten iron in the presence of a base, usually
calcium oxide. Explain how the percentage of carbon is reduced and how the silicon is
removed.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]

4
For
(b) (i) Why are steel alloys used in preference to iron? Examiner’s
Use
.............................................................................................................................. [1]
(ii) State a use of the following alloys.
mild steel ...................................................................................................................
stainless steel ...................................................................................................... [2]
(c) Both iron and steel have typical metallic structures - a lattice of positive ions and a sea
of electrons.
(i) Suggest an explanation for why they have high melting points.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Explain why, when a force is applied to a piece of steel, it does not break but just
changes its shape.
....................................................................................................................................
.............................................................................................................................. [2]
[Total: 11]
4 A major ore of zinc is zinc blende, ZnS. A by-product of the extraction of zinc from this ore is
sulfur dioxide which is used to make sulfuric acid.
(a) (i) Zinc blende is heated in air. Zinc oxide and sulfur dioxide are formed. Write the
balanced equation for this reaction.
.............................................................................................................................. [2]
(ii) Zinc oxide is reduced to zinc by heating with carbon. Name two other reagents
which could reduce zinc oxide.
.............................................................................................................................. [2]
(iii) The zinc obtained is impure. It is a mixture of metals. Explain how fractional distillation
could separate this mixture.
zinc bp = 908 °C, cadmium bp = 765 °C, lead bp = 1751 °C
....................................................................................................................................
.............................................................................................................................. [2]
© UCLES 2011 0620/31/M/J/11

5
For
(b) Sulfur dioxide is used to make sulfur trioxide in the Contact Process. Examiner’s
Use
2SO2(g) + O2(g) 2SO3(g)
The forward reaction is exothermic. The conditions used are:
temperature: 450 °C
pressure: 2 atmospheres
catalyst: vanadium(V) oxide
Explain, mentioning both position of equilibrium and rate, why these conditions give the
most economic yield.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
[Total: 10]
5 Hydriodic acid, HI(aq), is a strong acid. Its salts are iodides.
(a) It has the reactions of a typical strong acid. Complete the following equations.
(i) ............Li + ............HI → ........................ + ................... [1]
(ii) zinc hydriodic .......................... ..........................

+ → + + .........................
carbonate acid .......................... ..........................
[1]
(iii) MgO + ............HI → ................... + ................... [1]
(b) Two of the reactions in (a) are acid / base and one is redox. Which one is redox? Explain
your choice.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(c) Describe how you could distinguish between hydriodic, HI(aq), and hydrobromic, HBr(aq)
acids, by bubbling chlorine through these two acids.
result with hydriodic acid ..................................................................................................
result with hydrobromic acid ....................................................................................... [2]

6
For
(d) 20.0 cm3 of aqueous sodium hydroxide, 2.00 mol / dm3, was placed in a beaker. The Examiner’s
temperature of the alkali was measured and 1.0 cm3 portions of hydriodic acid were Use
added. After each addition, the temperature of the mixture was measured. Typical results
are shown on the graph.
temperature
18.0 cm3 volume of

acid added
NaOH(aq) + HI(aq) → NaI(aq) + H2O(l)
(i) Explain why the temperature increases rapidly at first then stops increasing.
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Suggest why the temperature drops after the addition of 18.0 cm3 of acid.
.............................................................................................................................. [1]
(iii) In another experiment, it was shown that 15.0 cm3 of the acid neutralised 20.0 cm3 of
aqueous sodium hydroxide, 1.00 mol / dm3. Calculate the concentration of the acid.
....................................................................................................................................
.............................................................................................................................. [2]
[Total: 12]
6 The structural formula of a butanol is given below.
CH3 — CH2 — CH2 — CH2 — OH
(a) Butanol can be made from petroleum and also by fermentation.
(i) Describe the chemistry of making butanol from petroleum by the following route.
petroleum → butene → butanol
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]
© UCLES 2011 0620/31/M/J/11

7
For
(ii) Explain, in general terms, what is meant by fermentation. Examiner’s
Use
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]
(b) Butanol can be oxidised to a carboxylic acid by heating with acidified potassium
manganate(VII). Give the name and structural formula of the carboxylic acid.
name ........................................................................................................................... [1]
structural formula
[1]
(c) Butanol reacts with ethanoic acid to form a liquid, X, which has the sweet smell of
bananas. Its empirical formula is C3H6O and its Mr is 116.
(i) What type of compound is liquid X?
.............................................................................................................................. [1]
(ii) Give the molecular formula of liquid X.
.............................................................................................................................. [1]
(iii) Draw the structural formula of X. Show all the individual bonds.
[2]
[Total: 12]

8
For
7 Excess hydrochloric acid was added to powdered zinc. The hydrogen evolved was collected Examiner’s
and its volume measured every 20 seconds. Use
The experiments were repeated at the same temperature using the same number of moles
of powdered magnesium and aluminium.
metal B
metal A
volume of
hydrogen
metal C
time
(a) Identify metals A, B and C by choosing from zinc, magnesium and aluminium. Give a
reason for each choice.
metal A .............................................................................................................................
...........................................................................................................................................
metal B .............................................................................................................................
...........................................................................................................................................
metal C .............................................................................................................................
..................................................................................................................................... [5]
(b) Using ‘moles’, explain why two of the metals form the same volume of hydrogen but the
third metal forms a larger volume.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
[Total: 8]
© UCLES 2011 0620/31/M/J/11

9
For
8 There are two types of polymerisation - addition and condensation. Examiner’s
Use
(a) Explain the difference between them.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(b) Poly(dichloroethene) is used to package food. Draw its structure. The structural formula
of dichloroethene is shown below.
H Cl
C C
H Cl
[2]
(c) The polymer known as PVA is used in paints and adhesives. Its structural formula is
shown below.
CH2 CH CH2 CH
OOCCH3 OOCCH3
[1]

10
For
(d) A condensation polymer can be made from the following monomers. Examiner’s
Use
[3]
[Total: 8]
© UCLES 2011 0620/31/M/J/11

11
BLANK PAGE
© UCLES 2011 0620/31/M/J/11

© UCLES 2011
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
12
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/31/M/J/11
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71

0620 CHEMISTRY
0620/31 Paper 3 (Extended Theory), maximum raw mark 80
examination.
syllabuses.
1 (a) F or B diffusion / fractional distillation [1]
(b) A simple distillation [1]
(c) D chromatography [1]
(d) E filtration [1]
(e) C evaporation [1]
(f) B fractional distillation [1]
2 (a) (i) photosynthesis or a photochemical reaction [1]

not an example, question requires a process
not devices which convert light into electricity
(ii) cell [1]

accept battery
not generator
(b) (i) correct formula [1]
cond following marks conditional on correct formula

If covalent mark 1 only
correct charges [1]
6x and 2o around anion [1]
do NOT penalise for incorrect coding
ignore electrons around potassium
(ii) correct formula [1]
If ionic mark 1 only

cond
2 bp and 2 nbp around selenium [1]
1 bp and 3 nbp around both chlorine atoms [1]
(iii) the ionic compound

higher melting point / boiling point / less volatile
conducts when molten or aqueous, covalent compound does not
is soluble in water, covalent is not / ionic insoluble in organic solvents, covalent soluble
in organic solvents
harder
any two [2]
note there has to be comparison between the ionic compound and the covalent
compound
not density

(c) base [1]

not alkali
accepts a proton [2]
accepts hydrogen ion / H+ only [1]
proton and H+ [2]
3 (a) any four max 4

carbon forms carbon dioxide / carbon monoxide [1]
this is a gas it escapes / blown out / diffuses [1]
silicon forms silicon(IV) oxide / silica [1]
/ silicon(IV) oxide present in impure iron
silicon(IV) oxide reacts with calcium oxide to form slag or calcium silicate [1]
slag removed from surface [1]
accept skimmed, syphoned, poured off
not tapped max [4]
accept correct formula or equations
not calcium oxide reacts with silicon
(b) (i) any sensible suggestion – harder/stronger/can be tailored for a specific use/more
resistant to corrosion [1]
not steel does not rust
(ii) mild steel – cars or any vehicle/bicycles/white goods/screws or nails/roof/bridges/tools/

buildings/ships/pipes/machinery etc. [1]
stainless steel – chemical plants/cooking utensils/jewellery/cutlery/surgical equipment/

kitchen sinks/pipes/etc. [1]
(c) (i) strong attractive forces / strong bonds / bonds hard to break / requires a lot of
energy to break bonds [1]
not between ions, not between positive and negative ions,
not between electrons
between positive ions and (negative) electrons / opposite charges attract [1]
(ii) because the layers, lattice or rows of ions/cations [1]

accept sheets of ions
not atoms / molecules / protons / nuclei
can move / slip / slide past each other [1]
4 (a) (i) 2ZnS + 3O2 → 2ZnO + 2SO2 [2]

not balanced only [1]
(ii) two reagents from named metal(s) more reactive than zinc/carbon monoxide [2]
not hydrogen
(iii) they have different boiling points [1]

cadmium will distil first then zinc leaving lead/lead distilled last [1]

(b) for a high yield need low temperature [1]

then rate would be too slow or uneconomic [1]
a discussion of optimum temperature could score mark 1 and 2
presence of catalyst would increase rate (at same temperature) [1]

does not alter the yield (at that temperature) [1]
/ economic rate at lower temperature, therefore higher yield
higher pressure which would increase yield / rate [1]

yield high enough / high pressure expensive [1]
max [4]
accept reverse arguments

note increase yield X position of equilibrium to right
5 (a) (i) 2Li + 2HI → 2LiI + H2 [1]
(ii) zinc carbonate + hydriodic acid → zinc iodide + carbon dioxide + water [1]
(iii) MgO + 2HI → MgI2 + H2O [1]
(b) reaction 1 is redox / Li/2HI reaction [1]

cond reason either oxidation number/state / electron transfer [1]
(c) with hydriodic acid – iodine formed / goes dark brown / grey/black solid [1]
not purple vapour not purple/black solution
with hydrobromic acid – bromine formed / goes orange / yellow / brown / reddish brown / red
/ brown vapour [1]
note can accept brown for iodine provided bromine is different orange/brown etc.
(d) (i) the reaction is exothermic / reaction produces heat/energy [1]

all the sodium hydroxide used up/neutralised / reaction has stopped [1]
(ii) adding colder acid / no more heat produced [1]

if not given in (d)(i) any comments such as “reaction has stopped” can gain mark
(iii) 1.33 / 1.3 / 1.3333 (mol/dm3) scores both marks [2]

not 1.34
for a correct method – M1 V1 / moles of NaOH = 0.02
with an incorrect answer only [1]

6 (a) (i) cracking / heat with catalyst [1]

to make butane [1]
butene reacts with steam/water / hydrated [1]
accept heat and catalyst for cracking but if specified: 450 to 800°C zeolites /
aluminosilicates / silica / aluminium oxide/alumina / china / broken pot / porcelain /
chromium oxide
(ii) glucose / sugar changed to alcohol / ethanol [2]

accept an unbalanced equation
(catalysed by) enzymes / yeast [1]
(b) butanoic acid [1]

CH3-CH2-CH2-COOH [1]
hydrogen atoms omitted from ends of bonds, penalise once
(c) (i) ester [1]
(ii) C6H12O2
ignore CH3COOC4H9 [1]
(iii) correct structural formula of butyl ethanoate showing all bonds [2]
7 (a) metal A is magnesium [1]

cond most reactive or fastest reaction [1]
metal B is aluminium [1]

cond faster reaction after removal of oxide layer / it would give more hydrogen / aluminium
more reactive than zinc [1]
metal C is zinc [1]

zinc least reactive [1]
NOTE MAX [5]
If you encounter different reasoning which is correct, please award the appropriate marks.
(b) for magnesium and zinc same volume of hydrogen [1]
because both have valency of 2 / 1 mole of metal gives 1 mole of hydrogen / 1 mole of metal
reacts with 2 moles of acid [1]
bigger volume for aluminium because its valency is 3 / 1 mole of metal gives 1.5 moles of
hydrogen / 1 mole of metal reacts with 3 moles of acid [1]
If you encounter different reasoning which is correct, please award the appropriate marks.
accept balanced equations

accept ionic charges as alternative to valency

8 (a) addition – polymer only product / only one product [1]

accept monomer has C=C
accept monomer and polymer have same empirical formula
accept no loss of material in polymerisation
not only one monomer
condensation – polymer and water / small molecule formed [1]
(b) -CH2 – CCl2-

repeat unit correct [1]
COND continuation [1]
(c) CH2=CHOOCCH3 [1]
COND amide correct linkage [1]
correct repeat units [1]
continuation [1]
not NH2 or COOH endings
[Total: 80]

CHEMISTRY 0620/51
Paper 5 Practical Test May/June 2011
CONFIDENTIAL INSTRUCTIONS
Great care should be taken to ensure that any confidential information given does not reach the
*6110546425*
candidates either directly or indirectly.
The teacher responsible for preparing the examination is not allowed to consult the question paper before the
examination. Teachers should, as part of the preparation of the examination requirements, carry out any tests
indicated on page 2 in order to satisfy themselves that the supplied materials are satisfactory.
The standard Report Form to be included with the scripts is given on pages 7 and 8. Please detach and
enclose it with the scripts. If scripts are despatched in more than one envelope, it is essential that a copy of
the Supervisor’s Results and of the Report Form are sent inside each envelope.
More material may be issued if required, without penalty, but this should not be necessary. Safety spectacles
may be provided if considered necessary.
Supervisors are advised to remind candidates that all substances in the examination should be treated with
caution. Please also see under ‘General Apparatus’ on the use of pipette fillers and safety goggles.
In accordance with COSHH (Control of Substances Hazardous to Health) Regulations, operative in the UK, a
hazard appraisal of the examination has been carried out.
Attention is drawn, in particular, to certain materials used in the examination. The following codes are used
where relevant.
C = corrosive substance F = highly flammable substance
H = harmful or irritating substance O = oxidising substance
N = harmful to the environment T = toxic substance
Hazard data sheets should be available from your suppliers.
If you have any queries regarding these Instructions, please contact CIE
by e-mail: International@cie.org.uk,
by phone: +44 1223 553554,
by fax: +44 1223 553558,
stating the Centre number, the nature of the query and the syllabus number quoted above.
IB11 06_0620_51CI/5RP
2
For Question 1
Each candidate will require
(a) one 50 cm3 measuring cylinder
(b) one 50 cm3 burette
(c) one or more 250 cm3 conical flasks
(d) 100 cm3 of aqueous potassium manganate(VII), KMnO4, of concentration 3.2 g / dm3, labelled
solution A
(e) 100 cm3 of aqueous potassium manganate(VII), KMnO4 of concentration 6.4 g / dm3, labelled
solution B
(f) 100 cm3 of aqueous hydrogen peroxide, H2O2. This solution should be freshly made, i.e.
the day before, and be of concentration 35 cm3 of 20 volume hydrogen peroxide in 1 dm3 of
0.5 mol / dm3 sulfuric acid, labelled solution C. (20 volume hydrogen peroxide is equivalent to
6 % hydrogen peroxide or 1.667 M)
(g) one spatula of manganese(IV) oxide in a test-tube, labelled manganese oxide
(h) access to water and distilled water
(i) one 10 cm3 measuring cylinder
(j) a white tile
(k) a Bunsen burner and matches
(l) splints
(m) a spatula
(n) test-tube
25 cm3 of solution C should require approximately 32 cm3 of solution A for the end-point.
© UCLES 2011 0620/51/CI/M/J/11

3
For Question 2
[F][H] (a) a stoppered test-tube containing about 10 cm3 of ethanol, labelled liquid M
(b) a stoppered test-tube containing about 10 cm3 of aqueous potassium iodide, labelled
liquid N, of concentration 0.1 mol / dm3
[N][H] (c) two stoppered, dry test-tubes, each containing one crystal of iodine, labelled iodine
The Supervisor should advise candidates not to touch the crystals.
(d) distilled water
(e) splints
(f) a rack of test-tubes
(g) cork or bung to fit test-tubes
(h) two dry watch glasses
(i) aqueous copper sulfate of concentration 0.1 mol / dm3
[N][H] (j) aqueous silver nitrate of suitable concentration to give a positive halide test
[C] (k) aqueous nitric acid of concentration 1 mol / dm3
[N][F][H] (l) about 1 cm3 of cyclohexane, labelled liquid T, in a stoppered test-tube
(m) a 10 cm3 measuring cylinder
(n) a Bunsen burner and matches
(o) teat pipettes
Labels do not need to include concentrations.
© UCLES 2011 0620/51/CI/M/J/11

4
THE SUPERVISOR’S REPORT IS ON PAGES 7 AND 8
© UCLES 2011 0620/51/CI/M/J/11

5
© UCLES 2011 0620/51/CI/M/J/11

6
© UCLES 2011 0620/51/CI/M/J/11

7
This form must be completed and returned in the envelope with the scripts.
REPORT ON PRACTICAL CHEMISTRY
JUNE 2011
1 (a) Supervisor’s Results
It is recommended that the Supervisor should be a chemistry teacher.
The Supervisor is asked to carry out the experiments in Questions 1 and 2 and to record
the results on a spare copy of the question paper clearly labelled ‘Supervisor’s Results’.
Failure to enclose these results and this report form may lead to candidates being unavoidably
penalised.
(b) The candidate numbers of candidates in each session were:
First session Second session
© UCLES 2011 0620/51/CI/M/J/11

8
2 The Supervisor is invited to report details of any difficulties experienced by candidates giving names
and candidate numbers. The report should include reference to:
(a) any general difficulties encountered in making preparations for the examination;
(b) difficulties due to faulty apparatus or materials;
(c) accidents to apparatus or materials.
Other cases of individual hardship, e.g. illness, temporary disability, should be reported direct to
UCLES on the normal Application for Special Consideration form.
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
DECLARATION (to be signed by the Principal)
The preparation of this practical examination has been carried out so as to maintain fully the security
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
SIGNED .............................................................................................................................. (Principal)
© UCLES 2011 0620/51/CI/M/J/11

*5258007914*
CHEMISTRY 0620/51
1 hour 15 minutes

Practical notes are provided on page 8.
Total
IB11 06_0620_51/4RP
2
For
1 You are going to investigate the reaction between two different solutions of potassium Examiner’s
manganate(VII), A and B, and an acidic solution of substance C. Use
Instructions
You are going to carry out three experiments.
(a) Experiment 1
Fill the burette with the solution A of potassium manganate(VII) to the 0.0 cm3 mark.
Using a measuring cylinder, pour 25 cm3 of solution C into the conical flask.
Add 1 cm3 of the solution A to the flask, with shaking. Continue to add solution A to the
flask until the mixture just turns permanently pink. Record the burette readings in the
table and complete the table.
Pour away the contents of the conical flask and rinse the flask with distilled water.
final burette reading / cm3

initial burette reading / cm3
difference / cm3
[3]
(b) Experiment 2
Empty the burette and rinse it first with distilled water, and then with a little of solution B.
Fill the burette with the solution B of potassium manganate(VII) solution to the 0.0 cm3
mark.
Repeat Experiment 1.
Record the burette readings in the table and complete the table.

difference / cm3
[3]
(c) Experiment 3
To about 2 cm3 of solution C in a test-tube, add one spatula measure of manganese(IV)

oxide. Note any observations and test the gas given off.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
© UCLES 2011 0620/51/M/J/11

3
For
(d) Identify the gas given off in Experiment 3. Examiner’s
Use
..................................................................................................................................... [1]
(e) (i) What colour change was observed when potassium manganate(VII) solution was
added to the flask in Experiment 1.
from ....................................................... to ....................................................... [1]
(ii) Why is an indicator not added to the flask?
.............................................................................................................................. [1]
(f) (i) In which experiment was the greatest volume of potassium manganate(VII) solution
used?
.............................................................................................................................. [1]
(ii) Compare the volumes of potassium manganate(VII) used in Experiments 1 and 2.
.............................................................................................................................. [1]
(iii) Suggest an explanation for the difference in volumes.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(g) If Experiment 2 was repeated using 12.5 cm3 of solution C, what volume of potassium
manganate(VII) solution would be used? Explain your answer.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(h) Give one advantage and one disadvantage of using a measuring cylinder for solution C.
advantage .........................................................................................................................
disadvantage .............................................................................................................. [2]
[Total: 21]

4
For
2 You are provided with two different liquids, M and N. Examiner’s
Carry out the following tests on each liquid, recording all of your observations in the table. Use
Conclusions must not be written in the table.
tests observations
(a) (i) Place a little of liquid M in a test-tube ......................................................................

and describe its smell and colour.
................................................................ [2]
(ii) Place a little of liquid N in a test-tube ......................................................................

and describe its smell and colour.
................................................................ [1]
(b) (i) Using a teat pipette, transfer a few ......................................................................

drops of M to a dry watch glass.
Touch the liquid with a lighted splint. ................................................................ [2]
(ii) Repeat (b)(i) using liquid N. ................................................................ [1]
(c) (i) Using a teat pipette, add about

1 cm3 of liquid M to a crystal of iodine .....................................................................
provided in a test-tube.
Stopper and shake the test-tube. ................................................................ [2]
(ii) Add about 1 cm3 of N to the other .....................................................................

crystal of iodine provided.
Stopper and shake the test-tube. ................................................................ [1]
(iii) Add a few drops of liquid T to the

mixture. ................................................................ [2]
Stopper and shake the test-tube.
(d) (i) To about 1 cm3 of liquid M, add a few

drops of dilute nitric acid and then ................................................................ [1]
aqueous silver nitrate.
(ii) Repeat (d)(i) using liquid N. ................................................................ [2]
(e) To about 2 cm3 of liquid N, add about

2 cm3 of aqueous copper sulfate. .....................................................................
Shake and leave to stand for five
minutes. ................................................................ [2]
© UCLES 2011 0620/51/M/J/11

5
For
(f) What type of substance is liquid M? Examiner’s
Use
...........................................................................................................................................
..................................................................................................................................... [2]
(g) Identify one ion present in liquid N.
..................................................................................................................................... [1]
[Total: 19]
© UCLES 2011 0620/51/M/J/11

6
BLANK PAGE
© UCLES 2011 0620/51/M/J/11

7
BLANK PAGE
© UCLES 2011 0620/51/M/J/11

8
Test for anions

produced
chloride (Cl –) acidify with dilute nitric acid, then white ppt.
[in solution] add aqueous silver nitrate
iodide (I–) acidify with dilute nitric acid, then yellow ppt.
nitrate (NO3–) add aqueous sodium hydroxide ammonia produced
[in solution] then aluminium foil; warm carefully
sulfate (SO42–) acidify with dilute nitric acid, then white ppt.
[in solution] aqueous barium nitrate

white ppt., soluble in excess giving white ppt., insoluble in excess
aluminium (Al 3+)
a colourless solution
copper (Cu2+) light blue ppt., insoluble in excess light blue ppt., soluble in excess
zinc (Zn2+) white ppt., soluble in excess giving white ppt., soluble in excess giving
a colourless solution a colourless solution
Test for gases
gas test and test results

© UCLES 2011 0620/51/M/J/11


0620 CHEMISTRY
0620/51 Paper 5 (Practical), maximum raw mark 40
examination.
syllabuses.
1 (a) Table of results for Experiment 1

initial and final volumes and differences completed correctly (1)
to 1 decimal place (1)
comparable to Supervisor’s report (1) ±4 cm3 [3]
(b) Table of results for Experiment 2

initial and final volumes and differences completed correctly (1)
comparable to Supervisor’s report (1) ±4 cm3 [3]
(c) bubbles/fizz/effervescence (1) glowing splint (1) relights/brighter (1)

ignore reference to black [3]
(d) oxygen/O2 (1) [1]
(e) (i) colourless not clear to pink/purple (1) or reverse [1]
(ii) potassium manganate is coloured/is an indicator/owtte (1) [1]

allow not an acid/alkali reaction
(f) (i) experiment 1 (1) [1]
(ii) experiment 1 two times the volume of experiment 2 [1]
(iii) solution B/potassium manganate more concentrated/stronger (1) or converse

two times (1)
two times as concentrated = 2 [2]
(g) half the value of the result for experiment 2 (1) cm3 (1)
half the volume of C used (1) [3]
(h) advantage easy to use/quick/convenient/fairly accurate (1)

disadvantage not accurate owtte (1) [2]

2 (a) (i) colourless (1) smell (1) [2]
(ii) colourless/pale yellow and no smell (1) [1]
(b) (i) catches fire/ignites (1)

yellow/blue (1)
yellow flame = 2 [2]
(ii) extinguished/no reaction/owtte (1) [1]
(c) (i) yellow/brown/orange/red (1) solution/dissolves (1) not ppt. [2]
(ii) yellow/brown/orange (1) [1]
(iii) two layers/rings (1) pink/purple top layer (1) [2]
(d) (i) no reaction/no change/remains clear/stays same (1) [1]
(ii) yellow (1) precipitate (1) [2]
(e) brown/yellow/cream/white (1)

precipitate (1) [2]
(f) organic (1) alcohol/named alcohol/fuel (1) allow flammable [2]
(g) iodide/I– (1) not iodine [1]
[Total: 40]

*4839073064*
CHEMISTRY 0620/61
Paper 6 Alternative to Practical May/June 2011
1 hour
The number of marks is given in brackets [ ] at the end of each question or part For Examiner’s Use
question.
1
Total
IB11 06_0620_61/5RP
2
For
1 A student heated hydrated zinc sulfate crystals, ZnSO4.7H2O, using the apparatus below to Examiner’s
obtain a sample of water. Use
ice cubes
in water
(a) Complete the box to identify the piece of apparatus labelled. [1]
(b) Use labelled arrows to indicate:
(i) where the heat is applied,
(ii) where the sample of water would collect. [2]
(c) State the purpose of the ice cubes.
..................................................................................................................................... [1]
(d) Describe a physical test for pure water.
test ....................................................................................................................................
result ........................................................................................................................... [2]
[Total: 6]
© UCLES 2011 0620/61/M/J/11

3
For
2 Hydrochloric acid reacts with aqueous sodium thiosulfate to form a precipitate, which makes Examiner’s
the solution turn cloudy. Use
The formation of the precipitate can be used to show how fast the reaction proceeds, using
the apparatus shown below.
eye
10 cm3 of hydrochloric acid
conical flask
aqueous sodium thiosulfate
printed sheet
printed text
A student used this method to investigate the effect of changing the concentration of the
sodium thiosulfate solution on the speed of the reaction.
The student used different concentrations of sodium thiosulfate solution.
All other variables were kept the same.
(a) Give two variables which were kept the same in the investigation.
1. .......................................................................................................................................
2. ................................................................................................................................. [2]

4
For
The results of the experiments are shown plotted on the grid below. Examiner’s
Use
0.20
0.16
0.12
speed of reaction
/ arbitrary units
0.08
0.04
0.00
0.0 0.1 0.2 0.3
concentration of sodium thiosulfate in mol / dm3
(b) Draw a line of best fit on the grid. [1]
(c) Suggest two reasons why not all of the points lie on the line of best fit.
1. .......................................................................................................................................
2. ................................................................................................................................. [2]
(d) From your graph, deduce the speed of reaction when the concentration of sodium
thiosulfate is 0.075 mol / dm3. Show clearly on the graph how you worked out your
answer.
..................................................................................................................................... [2]
(e) Explain why the speed of reaction increases when the concentration of sodium thiosulfate
is increased.
...........................................................................................................................................
..................................................................................................................................... [2]
(f) Sketch on the grid the line you would expect if the experiments were repeated at a higher
temperature. [1]
[Total: 10]
© UCLES 2011 0620/61/M/J/11

5
For
3 The colours present in some fruit sweets can be separated using the apparatus below. The Examiner’s
colours are water-soluble dyes. Use
solvent
(a) Name the process used to separate the colours.
..................................................................................................................................... [1]
(b) Name the solvent used.
..................................................................................................................................... [1]
The results obtained for the colours in two different sweets, C and D, are shown below.
sweet sweet
C D
(c) What is the name for the line at position B?
..................................................................................................................................... [1]
(d) What conclusions can you draw about the colours present in sweets C and D?
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
[Total: 6]

6
For
4 A student investigated the reaction between two different solutions of deep purple potassium Examiner’s
manganate(VII), A and B, and an acidic solution of hydrogen peroxide. Use
Three experiments were carried out.
Experiment 1
A burette was filled with the solution A of potassium manganate(VII) up to the 0.0 cm3 mark.
Using a measuring cylinder, 25 cm3 of colourless hydrogen peroxide solution was poured into
the conical flask.
The potassium manganate(VII) solution A was added slowly to the flask, and shaken to mix
thoroughly. Addition of potassium manganate(VII) solution was continued until there was a
permanent pink colour in the contents of the flask.
(a) Use the burette diagram to record the volume in the table of results and complete the
column. [2]
31
32
33
final reading
Experiment 2
Experiment 1 was repeated using the solution B of potassium manganate(VII) instead of

solution A.
(b) Use the burette diagrams to record the volumes in the table of results and complete the
table. [2]
18 34
19 35
20 36
initial reading final reading
experiment 1 experiment 2
final reading / cm3

initial reading / cm3
difference / cm3
© UCLES 2011 0620/61/M/J/11

7
For
Experiment 3 Examiner’s
Use
To a little of the hydrogen peroxide solution in a test-tube, manganese(IV) oxide was added.
Rapid effervescence was observed and a glowing splint relit.
(c) Identify the gas given off in Experiment 3.
..................................................................................................................................... [1]
(d) (i) What colour change was observed when potassium manganate(VII) solution was
added to the flask?
from ..................................................... to ..................................................... [1]
(ii) Why was an indicator not added to the flask?
.............................................................................................................................. [1]
(e) (i) In which experiment was the greatest volume of potassium manganate(VII) solution
used?
.............................................................................................................................. [1]
(ii) Compare the volumes of potassium manganate(VII) used in Experiments 1 and 2.
.............................................................................................................................. [1]
(iii) Suggest an explanation for the difference in volumes.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(f) If Experiment 2 was repeated using 12.5 cm3 of the hydrogen peroxide solution, what
volume of potassium manganate(VII) solution would be needed to react completely?
...........................................................................................................................................
..................................................................................................................................... [3]
(g) Give one advantage and one disadvantage of using a measuring cylinder for the
hydrogen peroxide solution.
advantage .........................................................................................................................
disadvantage .............................................................................................................. [2]
[Total: 16]

8
For
5 Two different liquids, M and N, were analysed. N was aqueous potassium iodide. Examiner’s
The tests on the liquids and some of the observations are in the following table. Use
Complete the observations in the table.
tests observations
(a) (i) Appearance of liquid M. colourless liquid with an antiseptic smell
(ii) Appearance of liquid N. ............................................................ [2]
(b) (i) A few drops of M were transferred

to a dry watch glass. The liquid was burns with a yellow flame
touched with a lighted splint.
(ii) Test (b)(i) was repeated using liquid N. ............................................................ [1]
(c) A little of liquid M was added to a crystal

of iodine in a test-tube. The test-tube was
shaken. orange-brown solution
(d) To a little of liquid N, a few drops of dilute

nitric acid was added, followed by silver
nitrate solution. ........................................................... [2]
(e) What type of substance is liquid M?
...........................................................................................................................................
..................................................................................................................................... [2]
[Total: 7]
© UCLES 2011 0620/61/M/J/11

9
BLANK PAGE

10
For
6 The reaction between aqueous barium chloride and aqueous sodium sulfate produces a Examiner’s
white precipitate. Use
Six experiments were carried out to find the mass of precipitate produced using solution P
and solution Q.
Solution P was aqueous barium chloride.

Solution Q was aqueous sodium sulfate.
Both solutions were of the same concentration.
5 cm3 of solution P was put into each of six test-tubes. Increasing volumes of solution Q were
added to each test-tube. The mixtures were filtered to obtain the precipitates, which were
washed, dried and then weighed in a suitable container.
(a) Draw a labelled diagram to show how the mixture was filtered.
[2]
The results are shown in the table below.
(b) Complete the table.
volume of volume of mass of mass of container mass of

P / cm3 Q / cm3 container / g and precipitate / g precipitate / g
5 1 4.50 4.95
5 2 4.50 5.45
5 3 4.50 5.90
5 4 4.50 6.40
5 5 4.50 6.85
5 6 4.50 6.85
[2]
© UCLES 2011 0620/61/M/J/11

11
For
(c) Plot the points on the grid below. Join the points with two intersecting straight lines. Examiner’s
Use
2.5
2.0
1.5
mass of
precipitate / g
1.0
0.5
0.0
0 1 2 3 4 5 6
volume of Q / cm3
[3]
(d) What is the minimum volume of Q required to completely react with 5 cm3 of P?
..................................................................................................................................... [1]
[Total: 8]

12
For
7 The label shows some information on a bottle of liquid sink and drain cleaner. Examiner’s
Use
Contains:
sodium hydroxide, sodium
hypochlorite
contact with acids liberates
chlorine
rinse container with water
before throwing out
(a) Give a chemical test for the presence of sodium hydroxide.
test ....................................................................................................................................
result ........................................................................................................................... [2]
(b) Suggest why it could be dangerous to pour fizzy drinks into a sink containing this liquid
cleaner.
...........................................................................................................................................
..................................................................................................................................... [2]
(c) Why should the container be rinsed with water before throwing out?
..................................................................................................................................... [1]
(d) Give a chemical test for chlorine.
test ....................................................................................................................................
result ........................................................................................................................... [2]
[Total: 7]
© UCLES 2011 0620/61/M/J/11


0620 CHEMISTRY
0620/61 Paper 6 (Alternative to Practical), maximum raw mark 60
examination.
syllabuses.
1 (a) beaker (1) [1]
(b) (i) (arrow) labelled heat in correct position under shaded crystals (1)
(ii) arrow labelled water in test-tube at or below the level of the ice (1) [2]
(c) to cool/condense the water or steam/owtte (1) [1]
(d) physical test ignore chemical tests

boiling point/freezing point (1)
100/0°C (1) [2]
2 (a) any two variables max 2

• volume
• concentration of acid allow amount
• volume of sodium thiosulfate/total volume of solution
• temperature
• printed sheet
• same size flask
ignore reference to pressure/catalyst/surface area/light max [2]
(b) straight line drawn with a ruler, missing anomalous point but touching all other points (1)
not multiple lines [1]
(c) any two sensible errors that could be from same category max 2
• qualified measurement error e.g. volume
• qualified timing error
• recording error
• plotting error
• temperature variation
• contamination from previous experiment
not systematic error max [2]
(d) 0.056–0.064 range (1) indication on graph (1) [2]
(e) more particles/particles closer together (1) more collisions (1) [2]
(f) sketch straight line to the LEFT of the original (1) [1]

3 (a) chromatography (1) [1]
(b) water (1) [1]
(c) origin/base line/datum (1) [1]

ignore references to start/initial/pencil
(d) sweet C has 4 colours (1)

sweet D has 3 colours (1)
allow C has one more colour/more colours than D for one mark
2 colours are the same (1) [3]
4 Experiment 1
(a) and (b) initial and final volumes completed correctly (1) 0.0, 32.0
Experiment 2
initial and final volumes completed correctly (1) 19.0, 35.0
all readings in both experiments to 1 decimal place (1)

both differences correctly calculated (1) [4]
(c) oxygen(1) [1]
(d) (i) colourless not clear to purple/pink (1) or reverse [1]
(ii) potassium manganate is coloured/owtte (1) [1]

accept is not an acid/alkali reaction
(e) (i) experiment 1(1) allow ecf [1]
(ii) experiment 1 2× volume of experiment 2 [1]
(iii) solution B more concentrated/stronger (1) or converse

2× as concentrated (2) [2]
(f) half value from table result for experiment 2 / 8 (1) cm3 (1)
half volume of peroxide used (1) [3]
(g) advantage easy to use/quick/convenient/fairly accurate (1)

disadvantage not accurate owtte (1) [2]

5 (a) (ii) colourless (1) allow yellow no smell (1) [2]
(b) (ii) extinguished/owtte (1) [1]
(d) yellow (1) precipitate (1) [2]
(e) organic (1) allow hydrocarbon

fuel/alcohol/named alcohol (1) allow flammable [2]
6 (a) diagram of a filter paper in a funnel (1) label funnel/filter paper (1) [2]
(b) 0.45, 0.95, 1.40, 1.90, 2.35 and 2.35 (2), –1 for each incorrect up to 2 [2]
(c) all points plotted correctly (2), –1 for each incorrect point up to 2
two intersecting straight lines (1) ignore origin [3]
(d) 5 cm3 (1) ignore unit [1]
7 (a) appropriate test (1) result (1) [2]

e.g.
pH paper or named indicator 11–14 or correct colour
named metal salt solution/ion correct colour precipitate
ammonium salt/heat ammonia/owtte
(b) fizzy drinks may be acidic/contain carbon dioxide (1)

chlorine formed (1) toxic (1) max [2]
(c) answer connected to health and safety (1) [1]

allow to affect the environment/to clean it
(d) litmus/pH/UI paper (1) bleached owtte (1) [2]
[Total: 60]

CHEMISTRY 0620/11
45 Minutes
Soft clean eraser
*3111298563*

You may use a calculator.
IB12 06_0620_11/3RP
2
1 Which diagram shows the process of diffusion?
key
A
different
atoms
2 Which method is most suitable to obtain zinc carbonate from a suspension of zinc carbonate in
water?
A crystallisation
B distillation
C evaporation
D filtration
3 A student investigates how the concentration of an acid affects the speed of reaction with a 0.5 g
mass of magnesium at 30 °C.
The student has a beaker, concentrated acid, water and the apparatus below.
P a balance
Q a clock
R a measuring cylinder
S a thermometer
Which pieces of apparatus does the student use?
A P, Q and R only
B P, Q and S only
C Q, R and S only
D P, Q, R and S
© UCLES 2012 0620/11/M/J/12

3
4 An element Y has the proton number 18.
The next element in the Periodic Table is an element Z.
A Element Z has one more electron in its outer shell than element Y.
B Element Z has one more electron shell than element Y.
C Element Z is in the same group of the Periodic Table as element Y.
D Element Z is in the same period of the Periodic Table as element Y.
5 Which atom has twice as many neutrons as protons?

1 2 3 4
A 1H B 1H C 1H D 2 He
6 Which is a simple covalent molecule?
conducts electricity
volatile
when solid when molten
A
B
C
D
7 The electronic structures of atoms P and Q are shown.
key
P Q = electron
P and Q react to form an ionic compound.
What is the formula of this compound?
A PQ2 B P2Q C P2Q6 D P6Q2

4
8 The diagrams show the structures of two forms, P and Q, of a solid element.
P Q
What are suitable uses of P and Q, based on their structures?
use of solid P use of solid Q
A drilling drilling
B lubricating drilling
C drilling lubricating
D lubricating lubricating
9 The equation for the reaction between magnesium and dilute sulfuric acid is shown.
Mg + H2SO4 → MgSO4 + H2
Mr of MgSO4 is 120
Which mass of magnesium sulfate will be formed if 12 g of magnesium are reacted with sulfuric
acid?
A 5g B 10 g C 60 g D 120 g
© UCLES 2012 0620/11/M/J/12

5
10 Winston Churchill, a British Prime Minister, had his false teeth electroplated with gold.
The teeth were coated with a thin layer of carbon and were then placed in the apparatus shown.
switch
X Y
false teeth gold
aqueous solution
of a gold salt
Which row is correct?
the carbon powder

terminal X is
could be
A negative diamond
B negative graphite
C positive diamond
D positive graphite

6
11 The diagram shows that two gases are formed when concentrated hydrochloric acid is
electrolysed using inert electrodes.
+ve –ve
concentrated
hydrochloric acid
Which row correctly describes the colours of the gases at the electrodes?
anode (+ve) cathode (–ve)
A colourless colourless
B colourless yellow-green
C yellow-green colourless
D yellow-green yellow-green
12 The diagram shows the reaction between zinc oxide and dilute hydrochloric acid.
zinc oxide powder
dilute aqueous
hydrochloric acid zinc chloride
20 °C 22 °C
pH 1 pH 7
before after
Which terms describe the reaction?
endothermic neutralisation
A
B
C
D
© UCLES 2012 0620/11/M/J/12

7
13 The apparatus shown is used to measure the speed of a reaction.
gas syringe
reactants
Which equation represents a reaction where the speed can be measured using this apparatus?
A Mg(s) + 2HCl (aq) → MgCl 2(aq) + H2(g)
B HCl (aq) + NaOH(aq) → NaCl (aq) + H2O(l)
C Fe(s) + CuSO4(aq) → Cu(s) + FeSO4(aq)
D 2Na(s) + Br2(l) → 2NaBr(s)
14 The element vanadium, V, forms several oxides.
In which change is oxidation taking place?
A VO2 → V2O3
B V2O5 → VO2
C V2O3 → VO
D V2O3 → V2O5
15 A gas is escaping from a pipe in a chemical plant.
A chemist tests this gas and finds that it is alkaline.
What is this gas?
A ammonia
B chlorine
C hydrogen
D sulfur dioxide

8
16 The results of three tests on a solution of compound X are shown in the table.
test result
aqueous sodium hydroxide added white precipitate formed, soluble in excess

aqueous ammonia added white precipitate formed, insoluble in excess
acidified silver nitrate added white precipitate formed
What is compound X?
A aluminium bromide
B aluminium chloride
C zinc bromide
D zinc chloride
17 The graph shows how the pH changes as an acid is added to an alkali.
acid + alkali → salt + water
Which letter represents the area of the graph where both acid and salt are present?
A
14 B
pH
C
7
D
0
18 Dilute hydrochloric acid is added to a solid, S.
A flammable gas, G, is formed. Gas G is less dense than air.
What are S and G?
solid S gas G
A copper hydrogen
B copper carbonate carbon dioxide
C zinc hydrogen
D zinc carbonate carbon dioxide
© UCLES 2012 0620/11/M/J/12

9
19 The diagram shows a section of the Periodic Table.
Which element is described below?
‘A colourless, unreactive gas that is denser than air.’
20 Element X is below iodine in the Periodic Table.
Which row correctly shows the physical state of element X at room temperature and its reactivity
compared with that of iodine?
physical state
reactivity compared
of element X at
with that of iodine
room temperature
A gas less reactive

B solid less reactive
C gas more reactive
D solid more reactive
21 Which properties of the element titanium, Ti, can be predicted from its position in the Periodic
Table?
can be used conducts electricity forms coloured

has low density
as a catalyst when solid compounds
A
B
C
D

10
22 Five elements have proton numbers 10, 12, 14, 16 and 18.
What are the proton numbers of the three elements that form oxides?
A 10, 12 and 14
B 10, 14 and 18
C 12, 14 and 16
D 14, 16 and 18
23 Which statement about the uses of metals is correct?
A Aluminium is used in the manufacture of aircraft as it has a high density.

B Aluminium is used to make food containers as it conducts electricity.
C Stainless steel for cutlery is made by adding other elements to iron.
D Stainless steel is used to make chemical reactors as it corrodes readily.
24 Which statement about the extraction of iron from its ore is correct?
A Iron is more difficult to extract than zinc.

B Iron is more difficult to extract than copper.
C Iron is easy to extract because it is a transition metal.
D Iron cannot be extracted by reduction with carbon.
25 Metal X reacts violently with water.
Metal Y reacts slowly with steam.
Metal Z does not react with dilute hydrochloric acid.
What is the correct order of reactivity of these metals, most reactive first?
A X→Y→Z
B X→Z→Y
C Z→X→Y
D Z→Y→X
26 Which property is shown by all metals?
A They are extracted from their ores by heating with carbon.

B They conduct electricity.
C They form acidic oxides.
D They react with hydrochloric acid to form hydrogen.
© UCLES 2012 0620/11/M/J/12

11
27 Some uses of water are listed.
1 for drinking
2 in chemical reactions
3 in swimming pools
4 in washing
For which uses is it necessary to chlorinate the water?
28 Coal is a fossil fuel.
Which gas is not formed when coal burns?
A carbon dioxide
B carbon monoxide
C methane
D sulfur dioxide
29 Which is a use of oxygen?
A filling balloons
B filling light bulbs
C food preservation
D making steel
30 Fertilisers need to supply crops with three main elements.
Which compound contains all three of these elements?
A H3PO4 B KNO3 C NH4K2PO4 D NH4NO3

12
31 A new planet has been discovered and its atmosphere has been analysed.
atmosphere
planet
The table shows the composition of the atmosphere.
gas percentage by volume
carbon dioxide 4
nitrogen 72
oxygen 24
Which gases are present in the atmosphere of the planet in a higher percentage than they are in
the Earth’s atmosphere?
A carbon dioxide and oxygen

B carbon dioxide only
C nitrogen and oxygen
D nitrogen only
32 Gas X is a waste gas from digestion in animals.
Gas Y is formed when gas X is burnt with a small amount of oxygen.
Gas Z is formed when gas X is burnt with an excess of oxygen.
What are X, Y and Z?
X Y Z
A carbon dioxide methane carbon monoxide

B carbon monoxide methane carbon dioxide
C methane carbon dioxide carbon monoxide
D methane carbon monoxide carbon dioxide
© UCLES 2012 0620/11/M/J/12

13
substance X.
substance X
A calcium oxide
B sand
C sodium chloride
34 The structure of a compound is shown.
H H H O
H C C C C
H O H
Which functional groups are present in this compound?
alcohol alkene carboxylic acid
A
B
C
D
35 Which fraction from the fractional distillation of petroleum does not match its correct use?
fraction use
A fuel oil domestic heating

B kerosene jet fuel
C naphtha making roads
D refinery gas for heating and cooking

14
36 The diagram shows apparatus used to separate petroleum into four fractions.
thermometer
petroleum
on rock wool
water
heat
fraction
Which fraction contains the smallest hydrocarbon molecules?
fraction boiling point range / °C
A up to 70
B 70 to 120
C 120 to 170
D over 170
37 When a long chain hydrocarbon is cracked, the following products are produced.
1 C3H8
2 C2H4
3 C3H6
4 C2H6
Which products would decolourise bromine water?
© UCLES 2012 0620/11/M/J/12

15
38 PVA is a polymer. The monomer has the structure shown.
H O H
C C
H H
To which homologous series does this compound belong?
alcohols alkenes
A
B
C
D
39 Which equation represents incomplete combustion of ethane?
A C2H6 + O2 → 2CO + 3H2
B C2H6 + 2O2 → 2CO2 + 3H2
C 2C2H6 + 5O2 → 4CO + 6H2O
D 2C2H6 + 7O2 → 4CO2 + 6H2O
40 Ethanol is an important chemical produced by the ……1…… of ……2…… .
Which words correctly complete gaps 1 and 2?
1 2
A combustion ethane
B combustion glucose
C fermentation ethane
D fermentation glucose
© UCLES 2012 0620/11/M/J/12

© UCLES 2012
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/11/M/J/12
Indium Iodine
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71

0620 CHEMISTRY
examination.
syllabuses.
Question Question
Key Key
Number Number
1 C 21 A
2 D 22 C
3 D 23 C
4 B 24 B
5 C 25 A
6 D 26 B
7 B 27 B
8 B 28 C
9 C 29 D
10 B 30 C
11 C 31 A
12 C 32 D
13 A 33 A
14 D 34 C
15 A 35 C
16 B 36 A
17 D 37 B
18 C 38 A
19 D 39 C
20 B 40 D

*3940916627*
CHEMISTRY 0620/21
1 hour 15 minutes

At the end of the examination, fasten all your work securely together. For Examiner’s Use
question. 1
Total
IB12 06_0620_21/3RP
2
For
1 Stearic acid is a solid at room temperature. Examiner’s
The diagram below shows the apparatus used for finding the melting point of stearic acid. Use
The apparatus was heated at a steady rate and the temperature recorded every minute.
stirrer
water
stearic acid
heat
(a) State the name of the piece of apparatus labelled
A, ......................................................................................................................................
B. ................................................................................................................................ [2]
(b) (i) Suggest why the water needs to be kept stirred during this experiment.
....................................................................................................................................
.............................................................................................................................. [1]
(ii) Describe a chemical test for water.
test .............................................................................................................................
result .................................................................................................................... [2]
© UCLES 2012 0620/21/M/J/12

3
For
(c) A graph of temperature of stearic acid against time of heating is shown below. Examiner’s
Use
100
80
60
temperature / °C
40
20
0
0 2 4 6 8 10 12
time / minutes
(i) What was the temperature of the stearic acid after 3 minutes heating?
.............................................................................................................................. [1]
(ii) Use the information on the graph to determine the melting point of stearic acid.
.............................................................................................................................. [1]
(d) Describe the arrangement and motion of the particles in liquid stearic acid.
arrangement .....................................................................................................................
motion ......................................................................................................................... [2]

4
For
(e) A sample of stearic acid contained 1 % of another compound with a higher relative Examiner’s
molecular mass. Use
(i) Which one of the following statements about this sample of stearic acid is correct?
Tick one box.
Its density is exactly the same as that of pure stearic acid.
Its boiling point is the same as that of pure stearic acid.
Its melting point is different from pure stearic acid.
Its melting point is the same as that of pure stearic acid.
[1]
(ii) Describe one area of everyday life where the purity of substances is important.
.............................................................................................................................. [1]
[Total: 11]
© UCLES 2012 0620/21/M/J/12

5
For
2 The diagram below shows the structure of some substances, A, B, C, D and E. Examiner’s
Use
A B C
S S H H
S S
S S H C C S H
H H S
S S
H H
D E
Na+ Na+ Na+ Na+ S

S2– S2– O O
Na+ Na+ Na+ Na+

S2– S2–
(a) (i) Which one of these substances, A, B, C, D or E, is an element?
.............................................................................................................................. [1]
(ii) What do you understand by the term element ?
.............................................................................................................................. [1]
(b) Calculate the relative molecular mass of E.
[1]
(c) Write the simplest formula for D.
..................................................................................................................................... [1]
(d) Which substance, A, B, C, D or E, conducts electricity when it is molten?

...........................................................................................................................................
..................................................................................................................................... [2]
(e) The equation for the combustion of substance A is shown below.
2H2S + 3O2 → 2H2O + 2SO2
What type of chemical reaction is this?

decomposition neutralisation oxidation reversible

[1]
[Total: 7]

6
For
3 Hydrochloric acid and ethanoic acid are both acidic in nature. Examiner’s
Use
(a) Which one of the following is a pH value for an acidic solution.
pH 3 pH 7 pH 9 pH 13
[1]
(b) Describe how you would use litmus to test if a solution is acidic.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(c) Acids react with metal carbonates.
(i) Write a word equation for the reaction of calcium carbonate with hydrochloric acid.
[3]
(ii) Calcium carbonate can be used to treat acidic soil.

State one other use of calcium carbonate.
.............................................................................................................................. [1]
(iii) Name one other compound that can be used to treat acidic soil.
.............................................................................................................................. [1]
(d) Hydrochloric acid reacts with iron to form iron(II) chloride and hydrogen.
Complete the equation for this reaction.
Fe + ....HCl → FeCl 2 + ........

[2]
© UCLES 2012 0620/21/M/J/12

7
For
(e) (i) Complete the table below to show: Examiner’s
Use
● the molecular formula for ethanoic acid
● the full structural formula for ethanol.
ethanoic acid ethanol
H O
full structural formula H C C
H O H
molecular formula C 2 H6 O
[2]
(ii) Ethanol can be manufactured by the catalytic addition of steam to ethene. Complete
the equation for this reaction.
............ + .......... → C2H5OH

[1]
[Total: 14]

8
For
4 Fractional distillation is used to separate petroleum into different fractions. Examiner’s
Each fraction has a particular use. Use
(a) Match the fractions on the left with their uses on the right.
The first one has been done for you.
gas oil heating
bitumen fuel for ships
lubricating fraction surfacing roads
refinery gases waxes and polishes
naphtha making chemicals
[4]
(b) Petroleum fractions contain hydrocarbons.

What do you understand by the term hydrocarbon ?
..................................................................................................................................... [1]
(c) Methane, CH4, is a hydrocarbon.
(i) Draw the structure of methane, showing all atoms and bonds.
[1]
(ii) Complete the following equation for the burning of methane in excess oxygen.
CH4 + .....O2 → .......... + 2H2O

[2]
© UCLES 2012 0620/21/M/J/12

9
For
(iii) Methane belongs to a homologous series called the alkanes. Examiner’s
What do you understand by the term homologous series ? Use
....................................................................................................................................
.............................................................................................................................. [2]
(iv) Name the second member of the alkane homologous series.
.............................................................................................................................. [1]
[Total: 11]

10
For
5 A student investigated the reaction between zinc and hydrochloric acid using the apparatus Examiner’s
shown below. Use
The zinc was in excess.
zinc + hydrochloric acid → zinc chloride + hydrogen
measuring cylinder
small test-tube
held by a
piece of cotton
water
zinc powder
hydrochloric acid
(a) What should the student do to start the reaction?
..................................................................................................................................... [1]
(b) The student measured the volume of gas in the measuring cylinder at minute intervals.
The results are shown in the table.
time / minutes 0 1 2 3 4 5 6 7
volume of gas / cm3 0 15 23 30 33 35 35 35
(i) Plot the results on the grid below and draw the best curve through the points.
40
30
volume of
gas / cm3
20
10
0
0 1 2 3 4 5 6 7
time / minutes
[3]
© UCLES 2012 0620/21/M/J/12

11
For
(ii) Explain why the volume of gas stays the same after 5 minutes. Examiner’s
Use
....................................................................................................................................
.............................................................................................................................. [2]
(c) Complete the following sentences about this reaction using words or phrases from the
list below.
concentration decreases increases
speed stays the same volume
When the ............................. of hydrochloric acid is increased, the volume of gas given
off in the first two minutes ............................. . Decreasing the temperature of the reaction
mixture ............................. the ............................. of the reaction. [4]
(d) When the reaction is complete, the flask contains a mixture of zinc and aqueous zinc
chloride.
Describe how you can obtain pure dry crystals of zinc chloride from this reaction mixture.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
[Total: 13]

12
For
6 Lithium, sodium and potassium are in Group I of the Periodic Table. Examiner’s
Use
(a) The equation for the reaction of lithium with water is
2Li + 2H2O → 2LiOH + H2
(i) Write a word equation for this reaction.
.............................................................................................................................. [2]
(ii) Sodium reacts with water in a similar way to lithium.

Write a symbol equation for the reaction of sodium with water.
[1]
(b) Describe the reactions of lithium, sodium and potassium with water.
In your description, write about:
● the difference in the reactivity of the metals

● the observations you would make when these metals react with water.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [5]
© UCLES 2012 0620/21/M/J/12

13
For
(c) The diagram below shows an electrolysis cell used to manufacture sodium from molten Examiner’s
sodium chloride. Use
– –
A
E
+
(i) Which letter in the diagram above represents
the anode? ..............
the electrolyte? .............. [2]
(ii) State the name of the product formed
at the positive electrode, ............................................................................................
at the negative electrode. .................................................................................... [2]
(iii) Which one of the following substances is most likely to be used for the anode?
graphite iodine magnesium sodium

[1]
(d) Lithium, sodium and potassium are metals with a low density.
State two other physical properties of these metals.
1. .......................................................................................................................................
2. ................................................................................................................................. [2]
[Total: 15]

14
For
7 (a) The equations A and B below show two reactions which lead to the formation of acid Examiner’s
rain. Use
A S + O2 → SO2
B SO2 + O3 → SO3 + O2
(i) Write a word equation for reaction A.
.............................................................................................................................. [2]
(ii) Which two of the following statements about reaction B are correct?
Tick two boxes.
SO2 is oxidised to SO3
SO2 is reduced to SO3
O3 is reduced to O2
O3 is oxidised to O2 [2]
(iii) Complete the equation to show how an aqueous solution of sulfuric acid, H2SO4, is
formed from SO3.
SO3 + ........ → H2SO4

[1]
(b) Describe and explain the effect of sulfuric acid on buildings made from limestone (calcium
carbonate).
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(c) State one effect of acid rain other than on buildings.
..................................................................................................................................... [1]
[Total: 9]
© UCLES 2012 0620/21/M/J/12

15
BLANK PAGE
© UCLES 2012 0620/21/M/J/12

© UCLES 2012
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/21/M/J/12
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71

0620 CHEMISTRY
examination.
syllabuses.
1 (a) A: thermometer; [1]

B: beaker; [1]
(b) (i) idea that heat is evenly distributed e.g.

to make sure that temperature (of water) is the same throughout / the heat gets to the
(stearic) acid at steady rate / the heart gets to test tube at a constant rate / to make sure
the water is at an even temperature (throughout) / so not just hot at the bottom / so that
hot parts of the water mix with cold; [1]
(ii) anhydrous / white copper sulfate; [1]

turns blue; [1]
or
anhydrous / blue cobalt chloride;
turns pink / turns red;
allow: second mark if copper sulfate or cobalt chloride given without reference to colour
or anhydrous
(c) (i) 48(°C); [1]
(ii) 72(°C); [1]
(d) arrangement: close together / touching / irregular / random; [1]
motion: sliding over each other / moving slowly; [1]

allow: irregular / random
allow: move faster than solid but slower than gas
(e) (i) the melting point is different / 3rd box down ticked; [1]
(ii) any suitable: e.g.

food / medicines / drugs / named food / medicine / cosmetics / drinking water / water for
cooking / water for washing; [1]
allow: relevant places or processes where purity of substances is important e.g.
drinking / eating / cooking / surgeries / hospitals / kitchen
[Total: 11]
2 (a) (i) B; [1]

allow: sulfur / S8 / S
(ii) a substance containing only one type of atom; [1]

allow: a substance with the same type of atoms / a substance containing the same
atoms / a substance that cannot be broken down (by chemical means)
(b) 64 [1]
(c) Na2S [1]

(d) D; [1]
ions can move / ions are free; [1]
note: second mark dependent on first mark being correct
(e) oxidation; [1]
[Total: 7]
3 (a) pH 3; [1]
(b) dip (litmus) paper in the solution / acid or add litmus solution to the acid / add acid to litmus
paper; [1]
note: if another substance added e.g. add a metal or a further process e.g. boil the solution,
the first mark is lost but the next two marks can still be obtained.
blue litmus; [1]
turns red / pink; [1]

reject: litmus bleaches
note: if the indicator is incorrect, the second two marks cannot be obtained.
(c) (i) calcium carbonate + hydrochloric acid → calcium chloride + carbon dioxide + water [3]
note: –1 per error
(ii) extraction of iron / making cement / making lime / neutralising acidic lakes /
(flue gas) desulfurisation / making glass / neutralising acidic waste / any other suitable
use; [1]
(iii) calcium oxide; [1]

allow: calcium hydroxide / lime / milk of lime / other carbonates
allow: correct formulae
(d) H2 (on right); [1]

correct balance (i.e. 2 on left); [1]
(e) (i) molecular formula of ethanoic acid is C2H4O2; [1]

full structural formula of ethanol is: [1]
H H
│ │
H―C—C—O—H
│ │
H H
allow: OH in place of O- H
(ii) C2H4 + H2O; [1]
[Total: 14]

4 (a) bitumen → surfacing roads; [1]

lubricating fraction → waxes and polishes; [1]
refinery gases → heating; making chemicals [1]
allow: refinery gas → making chemicals
naphtha → making chemicals; [1]
(b) substance containing hydrogen and carbon only; [1]
(c) (i) H [1]

│
H—C—H
│
H
(ii) CO2 (on right); [1]
correct balance (i.e. 2 on left) [1]
note: balance mark dependent on CO2 on right
(iii) any two of: [2]

family of similar (organic) compounds /
with similar chemical properties /
presence of same functional group /
same general formula /
allow: compounds with a trend in physical properties

allow: difference of CH2 between one member and another
(iv) ethane; [1]
[Total: 11]

5 (a) lower the test tube (into the HCl) / mix the reactants / mix the zinc and hydrochloric acid; [1]
(b) (i) all points plotted correctly including the 0-0 point; [2]
curve of best fit drawn; [1]
(ii) because the reaction has finished / reaction has stopped / reaction is complete; [1]
the hydrochloric acid has been used up / hydrochloric acid is limiting / the limiting
reagent has been used up; [1]
reject: the zinc has been used up / the zinc and hydrochloric acid have been used up
(c) concentration; increases; decreases; speed; (1 mark each) [4]
(d) filter (off excess zinc) / decant (off solution); [1]

note: if no filtration or decantation no further marks can be scored
heat filtrate to crystallisation point / evaporate some of the water / heat for a little while / leave
filtrate in a warm place / leave on the windowsill; [1]
dry crystals with filter paper; [1]

allow: dry in oven below 100°C
[Total: 13]
6 (a) (i) lithium + water → lithium hydroxide + hydrogen [2]

(ii) 2Na + 2H2O → 2NaOH + H2 [1]

allow: equations doubling or halving all species

(b) 2 marks for order of reactivity:

• order of reactivity is potassium > sodium > lithium / implication of rate of bubble
formation or some other observation clearly shows the order is potassium > sodium >
lithium; [2]
note: reactivity increases down group / only two of the elements are named but they are in
correct order of reactivity e.g. potassium is more reactive than sodium = 1 mark
3 marks for observations: [3]

any 3 of:
• float on surface (with any of the 3 elements)
• bubbles given off / effervescence (with any of the 3 elements)
• fizzes / sound heard (with any of the 3 elements)
• Na / K go into a ball OR Na / K melt ignore: Li goes into ball or melts
allow: they go into a ball
• move across the surface of the water) (with any of the 3 elements)
• K (bursts into) flame
• lilac / violet flame for K
allow: Na (bursts into) flame / yellow flame
• Na / K spits / explodes (when gets very small) allow: pops or sparks (for Na or K)
• Li / Na / K disappears / gets smaller
(c) (i) anode: E; [1]

electrolyte: A; [1]
(ii) + electrode: chlorine / Cl2; [1]

– electrode: sodium / Na; [1]
reject: ions / chloride
(iii) graphite; [1]
(d) any two of: [2]

• shiny (when cut)
• conduct heat
• conduct electricity
• malleable / soft / easy to cut
• ductile
[Total: 15]
7 (a) (i) sulfur + oxygen → sulfur dioxide [2]

(sulfur + oxygen → sulfur oxide / sulfur trioxide) = 1 mark
(ii) SO2 oxidised to SO3 / 1st box ticked; [1]

O3 reduced to O2 / 3rd box ticked; [1]
(iii) H2O; [1]

(b) any 3 of; [3]

• (sulfuric acid) reacts (with calcium carbonate)
• neutralisation (reaction)
• gas released / CO2 released
• soluble substances formed (on reaction)
• buildings eroded / (surface) crumbled / damaged / pitted /
note: a correct word or symbol equation = 2 marks

note: neutralisation reaction = 2 marks
(c) kills (or harms) organisms in lakes / forest death / deforestation / kills trees / kills plants /
damages plants / irritation of throat or lungs / reference to asthma; [1]
allow: kills (or harms) animals or fish in lakes or rivers / kills corals.
allow: leaches soil minerals
allow: leaf burn
ignore: kills animals / fish in the sea / kills fish unqualified
ignore: acidifies soil / acidifies lakes
ignore: wears away / erodes carbonate rocks / erodes soil
ignore: destroys plants / animals
[Total: 9]

*0978813545*
CHEMISTRY 0620/31
1 hour 15 minutes

A copy of the Periodic Table is printed on page 12. For Examiner’s Use
At the end of the examination, fasten all your work securely together. 1
question. 2
Total
IB12 06_0620_31/4RP
2
For
1 The diagram below shows part of the Water Cycle. Examiner’s
Use
cloud
H2O(l) H2O(g)
Sun
rain
land
H2O(l) sea
(a) (i) State the name of each of the following changes of state.
H2O(l) → H2O(g)
name ..........................................................................................................................
H2O(g) → H2O(l)
name ..........................................................................................................................
[2]
(ii) Which one of the above changes of state is exothermic? Explain your choice.
....................................................................................................................................
.............................................................................................................................. [1]
(b) The rain drains into rivers and then into reservoirs. Describe how water is treated before
it enters the water supply.
...........................................................................................................................................
..................................................................................................................................... [2]
(c) (i) Explain how acid rain is formed.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [4]
© UCLES 2012 0620/31/M/J/12

3
For
(ii) Fish live in water which is neutral (neither acidic nor alkaline). Acid rain decreases Examiner’s
the pH of water in lakes and rivers. Both of the bases, calcium oxide and calcium Use
carbonate, can neutralise this acid and increase the pH. Explain why calcium
carbonate is a better choice.
....................................................................................................................................
.............................................................................................................................. [2]
[Total: 11]
2 Three ways of making salts are
● titration using a soluble base or carbonate

● neutralisation using an insoluble base or carbonate
● precipitation.
(a) Complete the following table of salt preparations.
method reagent 1 reagent 2 salt
titration ................................... ................................... sodium nitrate
................................... ...................................
neutralisation nitric acid ................................... copper(II) nitrate
...................................
precipitation ................................... ................................... silver(I) chloride
................................... ...................................
neutralisation sulfuric acid zinc(II) carbonate ...................................
...................................
[6]
(b) (i) Write an ionic equation with state symbols for the preparation of silver(I) chloride.
.............................................................................................................................. [2]
(ii) Complete the following equation.
ZnCO3 + H2SO4 → ............... + ............... + ...............

[2]
[Total: 10]

4
For
3 The Group I metals show trends in both their physical and chemical properties. Examiner’s
Use
(a) (i) How do their melting points vary down the Group?
.............................................................................................................................. [1]
(ii) Which element in the Group has the highest density?
.............................................................................................................................. [1]
(iii) All Group I metals react with cold water. Complete the following equation.
........Rb + ........H2O → ................ + ................

[2]
(b) Lithium reacts with nitrogen to form the ionic compound, lithium nitride.
(i) State the formula of the lithium ion. .............…….. [1]
(ii) Deduce the formula of the nitride ion. .............…….. [1]
(iii) In all solid ionic compounds, the ions are held together in a lattice.
Explain the term lattice.
....................................................................................................................................
.............................................................................................................................. [1]
(iv) What is the ratio of lithium ions to nitride ions in the lattice of lithium nitride?
Give a reason for your answer.
........ lithium ions : ........ nitride ions
....................................................................................................................................
.............................................................................................................................. [2]
[Total: 9]
4 Vanadium is a transition element. It has more than one oxidation state.

The element and its compounds are often used as catalysts.
(a) Complete the electron distribution of vanadium by inserting one number.
2 + 8 + .......... + 2
[1]
(b) Predict three physical properties of vanadium which are typical of transition elements.
1. .......................................................................................................................................
2. .......................................................................................................................................
3. ................................................................................................................................. [2]
© UCLES 2012 0620/31/M/J/12

5
For
(c) Vanadium(V) oxide is used to catalyse the exothermic reaction between sulfur dioxide Examiner’s
and oxygen in the Contact Process. Use
2SO2 + O2 2SO3
The rate of this reaction can be increased either by using a catalyst or by increasing the
temperature. Explain why a catalyst is used and not a higher temperature.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(d) The oxidation states of vanadium in its compounds are V(+5), V(+4), V(+3) and V(+2).
The vanadium(III) ion can behave as a reductant or an oxidant.
(i) Indicate on the following equation which reactant is the oxidant.
2V3+ + Zn → 2V2+ + Zn2+

[1]
(ii) Which change in the following equation is oxidation?

Explain your choice.
V3+ + Fe3+ → V4+ + Fe2+
....................................................................................................................................
.............................................................................................................................. [2]
[Total: 8]
5 Reactive metals tend to have unreactive compounds. The following is part of the reactivity
series.
sodium most reactive

calcium
zinc
copper
silver least reactive
(a) Sodium hydroxide and sodium carbonate do not decompose when heated.
The corresponding calcium compounds do decompose when heated.
Complete the following equations.
.................................... ....................................
calcium carbonate → +
.................................... ....................................
Ca(OH)2 → ................ + ................ [2]

6
For
(b) All nitrates decompose when heated. Examiner’s
Use
(i) The equation for the thermal decomposition of silver(I) nitrate is given below.
2AgNO3 → 2Ag + 2NO2 + O2
What are the products formed when copper(II) nitrate is heated?
.............................................................................................................................. [1]
(ii) Complete the equation for the action of heat on sodium nitrate.
..........NaNO3 → ........................ + ........................

[2]
(c) Which of the metals in the list on page 5 have oxides which are not reduced by carbon?
..................................................................................................................................... [1]
(d) Choose from the list on page 5, metals whose ions would react with zinc.
..................................................................................................................................... [2]
[Total: 8]
6 Butane is an alkane. It has the following structural formula.
H H H H
H C C C C H
H H H H
(a) The equation for the complete combustion of butane is given below. Insert the two
missing volumes.
2C4H10(g) + 13O2(g) → 8CO2(g) + 10H2O(g)
.......... .......... 40 volume of gas / cm3

[2]
(b) Butane reacts with chlorine to form two isomers of chlorobutane.
(i) What type of reaction is this?
.............................................................................................................................. [1]
(ii) Explain the term isomer.
....................................................................................................................................
.............................................................................................................................. [2]
© UCLES 2012 0620/31/M/J/12

7
For
(iii) Draw the structural formulae of these two chlorobutanes. Examiner’s
Use
[2]
(c) One of the chlorobutanes reacts with sodium hydroxide to form butan-1-ol. Butan-1-ol
can be oxidised to a carboxylic acid.
(i) State a reagent, other than oxygen, which will oxidise butan-1-ol to a carboxylic acid.
.............................................................................................................................. [1]
(ii) Name the carboxylic acid formed.
.............................................................................................................................. [1]
(iii) Butan-1-ol reacts with ethanoic acid to form an ester. Name this ester and give its
structural formula showing all the individual bonds.
name ................................................................................................................... [1]
structural formula
[2]
[Total: 12]

8
For
7 Plastics are polymers. They are formed from their monomers by polymerisation. Examiner’s
Use
(a) Two methods for the disposal of waste plastics are
● burning
● recycling.
Describe one advantage and one disadvantage of each method.
burning ..............................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
recycling ...........................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(b) (i) There are two types of polymerisation reaction. Give their names and explain the
differences between them.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [4]
(ii) Give the structural formula of a polymer which is formed from two different monomers.
[2]
[Total: 10]
© UCLES 2012 0620/31/M/J/12

9
For
8 Iron and steel rust when exposed to water and oxygen. Rust is hydrated iron(III) oxide. Examiner’s
Use
(a) The following cell can be used to investigate rusting.
electron flow
+ –
oxygen bubbled water

on to electrode
iron electrode A iron electrode B
iron(III) oxide
(rust)
(i) What is a cell?
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Which electrode will be oxidised and become smaller? Explain your choice.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]
(iii) What measurements would you need make to find the rate of rusting of the electrode
you have chosen in (ii)?
....................................................................................................................................
.............................................................................................................................. [2]
(iv) Suggest an explanation why the addition of salt to the water increases the rate of
rusting.
.............................................................................................................................. [1]

10
For
(b) A sample of rust had the following composition: Examiner’s
Use
51.85 g of iron 22.22 g of oxygen 16.67 g of water.
Calculate the following and then write the formula for this sample of rust.
number of moles of iron atoms, Fe = ................... [1]
number of moles of oxygen atoms, O = ................... [1]
number of moles of water molecules, H2O = ................... [1]
simplest mole ratio Fe : O : H2O is .......... : .......... : ..........
formula for this sample of rust is ................... [1]
[Total: 12]
© UCLES 2012 0620/31/M/J/12

11
BLANK PAGE
© UCLES 2012 0620/31/M/J/12

© UCLES 2012
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
12
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/31/M/J/12
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71

0620 CHEMISTRY
examination.
syllabuses.
1 (a) (i) evaporation / boiling / vaporisation / evaporate / vaporise; [1]

condensation / liquefaction / condense / liquefy; [1]
(ii) condensation accept: correct equation H2O(g)→H2O(l)

because energy / heat is given out / gas has more energy than liquid / need to supply
energy to change liquid to gas so reverse must give out energy / bonds form; [1]
(b) chlorination / chlorine to kill microbes; [1]
filtration or filter; [1]

accept: sedimentation or sand or gravel or grit
(c) (i) combustion of fossil fuels; [1]

(which contain) sulfur; [1]
sulfur dioxide formed; [1]
(reacts in air / with water to form) sulfurous / sulfuric acid; [1]
OR
nitrogen and oxygen in air; [1]
react at high temperatures / in engines; [1]
to form oxides of nitrogen or named oxide of nitrogen; [1]
(reacts in air / with water to form) nitrous / nitric acid; [1]
[max 4]
(ii) calcium oxide is soluble in water / reacts with water to form

calcium hydroxide; [1]
pH above 7 / the water becomes alkaline; [1]
OR
calcium carbonate insoluble in water; [1]
pH cannot be above 7 / water is neutral / does not make water alkaline; [1]
[max 2]
[Total: 11]
2 (a) nitric acid; [1]

sodium hydroxide / carbonate / hydrogen carbonate; [1]
copper(II) oxide / hydroxide / carbonate; [1]
any named soluble chloride; [1]

accept: hydrochloric acid / hydrogen chloride
silver(I) nitrate / ethanoate / sulfate; [1]
must be soluble silver salt not silver oxide / carbonate
zinc(II) sulfate [1]
(b) (i) Ag+(aq) + Cl –(aq) → AgCl(s) [2]

equation correct state symbols missing [1]
(ii) ZnCO3 + H2SO4 → ZnSO4 + CO2 + H2O [2]

correct formula for zinc sulfate = 1
[Total: 10]

3 (a) (i) decrease down group; [1]
(ii) caesium / francium; [1]
(iii) 2Rb + 2H2O → 2RbOH + H2 [2]

not balanced = [1]
(b) (i) Li+ [1]
(ii) N3– [1]
(iii) regular arrangement of ions / particles / positive and negative ions alternate; [1]
not: atoms
(iv) 3:1; [1]

ratio to balance charges / reason in terms of valency; [1]
[Total: 9]
4 (a) 2 + 8 + 11 + 2 [1]
(b) hard;
strong / high tensile strength;
high mp / bp / high fixed points;
high density; [2]
three properties = [2]

two properties = [1]
not: properties of all metals e.g. good conductor, lustre etc. or form coloured compounds
(c) catalyst would not affect yield / change position of equilibrium / affects both sides equally; [1]
(higher) temperature would reduce yield / increase in temperature would favour back
reaction; [1]
(d) (i) V3+ is oxidant; [1]
(ii) V3+ to V4+; [1]

increase in oxidation number / electron loss; [1]
[Total: 8]
5 (a) calcium carbonate → calcium oxide + carbon dioxide [1]

accept: correct symbol equation
Ca(OH)2 → CaO + H2O [1]
(b) (i) CuO and NO2 and O2; [1]

accept: names or correct formulae

(ii) 2NaNO3 → 2NaNO2 + O2 [2]

accept: NaNO3 → NaNO2 + 1/2 O2
not balanced = [1]
(c) Na / Ca; [1]
(d) Cu; Ag; [2]

accept: ions Cu2+ and Ag+
[Total: 8]
6 (a) 10 cm3; [1]

65 cm3; [1]
(b) (i) chlorination / substitution / photochemical / exothermic / halogenation / free radical; [1]
(ii) (compounds) same molecular formula; different structural formulae; [2]
(iii) CH3–CH2–CH2–CH2–Cl [1]

CH3–CH2–CH(Cl)–CH3 [1]
(c) (i) potassium manganate(VII) / potassium dichromate(VI) / copper(II) oxide; [1]

note: do not insist on oxidation numbers but if given must be correct
(ii) butanoic acid; [1]
(iii) butyl ethanoate; [1]
correct formula all bonds shown = [2]

if alkyl groups incorrect then correct ester linkage showing bonds = [1] [2]
[Total: 12]

7 (a) burning
produces toxic gases / harmful to health
increases greenhouse gases / global warming
reduces visual pollution / litter
reduces risks to wildlife
shortage of landfill sites / reduces space needed in landfill sites / saves space
non-biodegradable / long time to rot / decompose / accumulates waste
burning source of energy / used to generate electricity
recycling
conserves petroleum / natural resources
difficult to recycle / expensive / takes much energy
problems over sorting
reduces need for landfill
quality of plastic is reduced each time it is recycled
four DIFFERENT valid points which are advantages or disadvantages of burning and/or
recycling [4]
(b) (i) addition (polymerisation); [1]
(polymer) only product / no by-products; [1]
condensation (polymerisation); [1]
(polymer and) simple molecule / water / hydrogen chloride / one other product forms; [1]
(ii) a correct linkage (for a polyamide / polyester); [1]

two different monomers; [1]
[Total: 10]
8 (a) (i) device which changes chemical energy; [1]

into electrical energy; [1]
OR
produces a voltage / potential difference / electricity; [1]
due to difference in reactivity of two metals; [1]
OR
produces a voltage / potential difference / electricity; [1]
by redox reactions; [1]
(ii) negative / electrode B / right electrode; [1]

accept: anode because it is the electrode which supplies electrons to
external circuit
loses ions / iron ions / Fe2+ or Fe3+; [1]
electrons move from this electrode; [1]
(iii) change of mass of electrode / mass of rust formed; [1]

time / mention of stop watch / regular intervals; [1]
(iv) to make it a better conductor; [1]

(b) moles of Fe = 51.85/56 = 0.926 (0.93); [1]

moles of O = 22.22/16 = 1.389 (1.39); [1]
moles of H2O = 16.67/18 = 0.926 (0.93); [1]
if given as 0.9 1.4 0.9

three of the above correct = [2]
two of the above correct = [1]
simplest whole number mole ratio Fe : O : H2O is 2: 3: 2 / Fe2O3.2H2O; [1]

allow: ecf for a formula based on an incorrect whole number ratio
[Total: 12]

CHEMISTRY 0620/51
*9340926181*
where relevant.
by e-mail: International@cie.org.uk,
by phone: +44 1223 553554,
by fax: +44 1223 553558,
IB12 06_0620_51CI/RP
2
For Question 1
(a) one burette, clamped and secured in a stand
(b) one funnel to fit burette
[N][T] (c) 50 cm3 of aqueous lead nitrate, Pb(NO3)2, of concentration 0.5 mol / dm3 (165 g / dm3)
(d) 50 cm3 of aqueous potassium chloride, KCl , of concentration 0.5 mol / dm3 (37 g / dm3)
(e) one test-tube rack containing 6 identical test-tubes
(f) blank labels or marker pen to write on glass
(g) a stop clock or timer
(h) distilled water
(i) one glass stirring rod
(j) one 10 cm3 measuring cylinder
(k) ruler measuring in millimetres
© UCLES 2012 0620/51/CI/M/J/12

3
For Question 2
(a) a stoppered test-tube, containing about 2 g of sodium hydrogen carbonate, NaHCO3, labelled
solid W
(b) distilled water
(c) litmus papers
(d) pH indicator papers and chart
(e) rack of test-tubes
(f) limewater
(g) teat pipettes
[H] (h) 0.5 g ammonium chloride
(i) aqueous copper(II) sulfate of concentration 0.2 mol / dm3
(j) aqueous hydrochloric acid of concentration 1 mol / dm3
(k) spatulas
(l) one 10 cm3 measuring cylinder
(m) a Bunsen burner and matches
(n) test-tube holder
(o) one stirring thermometer 0-110 °C
(p) one boiling tube
© UCLES 2012 0620/51/CI/M/J/12

4
© UCLES 2012 0620/51/CI/M/J/12

5
© UCLES 2012 0620/51/CI/M/J/12

6
© UCLES 2012 0620/51/CI/M/J/12

7
JUNE 2012
penalised.
© UCLES 2012 0620/51/CI/M/J/12

8
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
© UCLES 2012 0620/51/CI/M/J/12

*4263914068*
CHEMISTRY 0620/51
1 hour 15 minutes

Total
IB12 06_0620_51/3RP
2
For
1 You are going to investigate the reaction between aqueous lead nitrate and aqueous Examiner’s
potassium chloride. Use
Read all the instructions below carefully before starting the experiment.
Instructions
You are going to carry out one experiment.
(a) Experiment
Using the measuring cylinder, pour 3 cm3 of the aqueous lead nitrate provided into
each of the six test-tubes in the test-tube rack. Label the test-tubes 1, 2, 3, 4, 5 and 6
respectively.
Fill the burette with the aqueous potassium chloride provided to the 0.0 cm3 mark.
From the burette add 1.0 cm3 of aqueous potassium chloride to test-tube 1.
Add 2.0 cm3 of aqueous potassium chloride to test-tube 2.
Add 4.0 cm3, 5.0 cm3, 6.0 cm3 and 7.0 cm3 of aqueous potassium chloride to test-tubes 3,
4, 5 and 6 respectively.
Using a glass rod carefully stir the contents of each of the test-tubes. Leave the contents
of the test-tubes to stand for 10 minutes.
You should start question 2 while waiting for the solid in the test-tubes to settle.
After 10 minutes, use a ruler to measure the height of the solid in each test-tube. Record
your results in the table.
volume of aqueous
test-tube number height of solid / mm
potassium chloride / cm3
6
[4]
© UCLES 2012 0620/51/M/J/12

3
For
(b) Plot your results on the grid below. Draw a line graph. Examiner’s
Use
height of solid / mm
0 1 2 3 4 5 6 7 8
volume of aqueous potassium chloride / cm3
[4]

4
For
(c) From your graph, find the height of the solid formed when 3.5 cm3 of aqueous potassium Examiner’s
chloride is added to 3 cm3 of aqueous lead nitrate. Use
Show clearly on the graph how you obtained your answer.
..................................................................................................................................... [3]
(d) What type of chemical reaction occurs when aqueous potassium chloride reacts with
aqueous lead nitrate?
..................................................................................................................................... [1]
(e) Describe the trend in the heights of the solids in test-tubes 1 to 6.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(f) Predict what would happen if the experiment were continued using three further
test-tubes with 8 cm3, 9 cm3 and 10 cm3 of aqueous potassium chloride. Explain your
answer.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(g) What difference would be observed if the experiment was repeated using aqueous silver
nitrate and aqueous potassium iodide?
...........................................................................................................................................
..................................................................................................................................... [1]
(h) Explain one improvement you could make to the experiment to obtain more accurate
results.
improvement .....................................................................................................................
explanation .......................................................................................................................
..................................................................................................................................... [2]
[Total: 19]
© UCLES 2012 0620/51/M/J/12

5
For
2 You are provided with solid W. Examiner’s
Carry out the following tests on W, recording all of your observations in the table. Use
tests observations
tests on solid W
(a) Describe the appearance of solid W. ................................................................ [1]
Use a spatula to place about one spatula

measure of W into each of four test-tubes to
carry out the tests in (b).
(b) (i) Heat solid W gently and then strongly. .....................................................................
................................................................ [2]
Leave the mixture to cool for five
minutes. Add about 2 cm3 of dilute .....................................................................
hydrochloric acid. Test the gas given
off with a lighted splint. ................................................................ [2]
(ii) Add about 2 cm3 of dilute hydrochloric .....................................................................

acid to solid W.
Test the gas given off. ................................................................ [3]
(iii) To solid W, add about 5 cm3 of

aqueous copper sulfate. .....................................................................
Heat the mixture gently. ................................................................ [2]
(iv) To solid W, add one spatula measure

of ammonium chloride and shake the
test-tube. Heat the mixture gently. .....................................................................
Test the gas given off with damp pH
indicator paper. ................................................................ [2]
tests on aqueous W
(c) Pour 10 cm3 of distilled water into a boiling

tube. Measure and record the temperature
of the water. ................................................................ [2]
Add the rest of solid W to the water and

stir with the thermometer. Measure and
record the temperature of the solution
after one minute. ................................................................ [1]
Use pH indicator paper to record the pH of

the solution. ................................................................ [1]

6
For
(d) Identify the gas given off in test (b)(ii). Examiner’s
Use
..................................................................................................................................... [1]
(e) Identify the gas given off in test (b)(iv).
..................................................................................................................................... [1]
(f) What type of change occurs when solid W dissolves in water in test (c)?
..................................................................................................................................... [1]
(g) What conclusions can you draw about solid W?
...........................................................................................................................................
..................................................................................................................................... [2]
[Total: 21]
© UCLES 2012 0620/51/M/J/12

7
BLANK PAGE
© UCLES 2012 0620/51/M/J/12

8
Test for anions

produced

aluminium (Al 3+)
Test for gases

© UCLES 2012 0620/51/M/J/12

MARK SCHEME for the May / June 2012 question paper

0620 CHEMISTRY
0620 / 51 Paper 5 (Practical), maximum raw mark 40
examination.
Cambridge is publishing the mark schemes for the May / June 2012 question papers for most IGCSE,
syllabuses.
1 (a) Table of results
volume of aqueous potassium chloride boxes completed correctly (1)

1,2,4,5, 6 and 7
heights of solid boxes completed (1) in mm (1)
ascending order / last 2 level out (1) [4]
(b) all points correctly plotted including origin (2), –1 for any incorrect
appropriate scale for y axis(at least half of grid) (1)
best fit straight line graph drawn with a ruler(1) [4]
(c) value from graph (1) unit (1) shown clearly (1) [3]
(d) precipitation / double decomposition (1) [1]
(e) height increases(1) levels off (1) [2]
(f) same heights owtte (1)
` all lead nitrate reacted / / reaction finished / excess potassium chloride (1) [2]
(g) yellow precipitate / solid (1) [1]
(h) improvement (1)
e.g. use burette or pipette / leave solid to settle longer / repeat /

wider range of volumes for KCl
explanation (1)
e.g. instead of a measuring cylinder / heights more accurate / take average /

more reliable / accurate [2]
2 (a) white (1) [1]
(b) (i) condensation / drops of liquid / water / steam (1)

solid is still white no (colour) change (1) [2]
fizzes / effervescence (1) lighted splint extinguished / owtte (1) [2]
(ii) fizz / bubbles / effervescence (1) limewater(1)

milky / cloudy / white precipitate (1) [3]
(iii) effervescence / fizz / bubbles (1)

darkens / turns black / green (1) ignore: blue [2]
(iv) description of smell of ammonia / sublimate (1)

pH paper turns blue / green or pH > 7 (1) allow: litmus goes blue [2]

(c) initial temperature recorded (1) oC (1)

final temperature recorded and lower (1) [3]
pH > 7 (1) [1]
(d) carbon dioxide (1) [1]
(e) ammonia (1) not: ammonium [1]
(f) endothermic (1) [1]
(g) hydrogencarbonate / carbonate (1) alkaline (1) not: sodium hydroxide

non transition metal (1) max 2 [2]

*0367948514*
CHEMISTRY 0620/61
1 hour
question.
Total
IB12 06_0620_61/4RP
2
For
1 A student reacted excess iron powder with sulfuric acid to prepare a solution of iron(II) Examiner’s
sulfate. Use
The diagram shows the procedure followed in three stages.
2
iron powder was added
until all the sulfuric acid
1 had reacted
50 cm3 of dilute sulfuric
acid was measured and
added to a beaker
heat
3
the mixture was solution of
allowed to cool iron(II) sulfate
(a) Complete the boxes to identify the pieces of apparatus labelled. [2]
(b) How would the student know when all of the sulfuric acid had reacted? Give two reasons.
1 ........................................................................................................................................
2 .................................................................................................................................. [2]
(c) Describe the effect of boiling the solution of iron(II) sulfate for several minutes.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
[Total: 7]
© UCLES 2012 0620/61/M/J/12

3
For
2 Heat is given out when alcohols are burned. Examiner’s
Use
A student used the apparatus below to find the amount of heat produced when four different
alcohols, methanol, ethanol, propanol and butanol, were burned.
thermometer
boiling tube
25 cm3 water
spirit burner
(a) Some methanol was put into the burner. The initial temperature of the water was measured.
The burner was lit and allowed to burn for one minute. The flame was extinguished and
the final temperature of the water was measured. The experiment was repeated with
ethanol, propanol and butanol.
Use the thermometer diagrams to record the temperatures in the table on page 4.
Complete the table by recording the temperature rise for each alcohol.

4
For
Examiner’s
initial final Use
thermometer thermometer temperature

alcohol formula temperature / °C temperature / °C
diagram diagram rise / °C
30 30
methanol CH3OH 25 25
20 20
30 40
ethanol C2H5OH 25 35
20 30
30 50
propanol C3H7OH 25 45
20 40
30 60
butanol C4H9OH 25 55
20 50
[4]
© UCLES 2012 0620/61/M/J/12

5
For
(b) Plot the results obtained on the grid and draw a straight line graph. Examiner’s
Use
50
40
30
temperature
rise / °C
20
10
0
0 1 2 3 4 5
number of carbon atoms
in the alcohol formula
[4]
(c) From your graph, work out the temperature rise expected if the experiment was repeated
using pentanol, C5H11OH.
Show clearly on the grid how you obtained your answer.
..................................................................................................................................... [3]
(d) Suggest the effect of using a copper can to contain the water instead of a boiling tube.
...........................................................................................................................................
..................................................................................................................................... [2]
[Total: 13]

6
For
3 Coffee beans contain caffeine and other compounds. Caffeine is soluble in water and in Examiner’s
trichloromethane, an organic solvent. Use
A student obtained crystals of caffeine by the following method.
Stage 1 Some coffee beans were crushed into small pieces.
Stage 2 Hot water was added to the crushed beans to dissolve the soluble substances.
Stage 3 The crushed beans were separated from the liquid solution.
Stage 4 The liquid was allowed to cool and shaken with trichloromethane to extract the
caffeine from the water.
Stage 5 The caffeine was crystallised from the trichloromethane solution.
Stage 6 The caffeine crystals were checked for purity.
(a) What apparatus should be used to crush the beans in Stage 1?
..................................................................................................................................... [2]
(b) How could the dissolving process in Stage 2 be speeded up?
..................................................................................................................................... [1]
(c) Draw a diagram of the apparatus used in Stage 3.
[2]
(d) How should Stage 5 be carried out?
...........................................................................................................................................
..................................................................................................................................... [2]
(e) What method could be used to check the purity of the crystals in Stage 6?
..................................................................................................................................... [1]
[Total: 8]
© UCLES 2012 0620/61/M/J/12

7
BLANK PAGE

8
For
4 A student investigated the reaction between aqueous lead nitrate and aqueous potassium Examiner’s
chloride. Use
(a) One experiment was carried out.
Using a measuring cylinder, 3 cm3 of aqueous lead nitrate was poured into each of six
test-tubes in a test-tube rack. The test-tubes were labelled A, B, C, D, E and F respectively.
A burette was filled with aqueous potassium chloride. A 1.0 cm3 sample of the aqueous
potassium chloride was added to test-tube A.
A 2.0 cm3 sample of aqueous potassium chloride was added to test-tube B.
A 4.0 cm3, 5.0 cm3, 6.0 cm3 and 7.0 cm3 sample of aqueous potassium chloride was added
to test-tubes C, D, E and F respectively.
Using a glass rod, the contents of the test-tubes were stirred. The contents of the
test-tubes were left to stand for 10 minutes.
After 10 minutes, a ruler was used to measure the height of the solid in each test-tube.
The diagrams show the six test-tubes in a rack. Use a ruler to measure the height of the
solid in each test-tube in the diagram. Record the heights of the solid in the table.
test-tube A B C D E F
solid
test-tube volume of aqueous

number potassium chloride / cm3
A
B
C
D
E
F
[4]
© UCLES 2012 0620/61/M/J/12

9
For
(b) Plot your results on the grid below. Draw two intersecting straight line graphs. Examiner’s
Use
25
20
15
height of
solid / mm
10
0
0 1 2 3 4 5 6 7
volume of aqueous potassium chloride / cm3
[4]
(c) From your graph, find the height of the solid formed when 3.5 cm3 of aqueous potassium
chloride was added to 3 cm3 of aqueous lead nitrate.
Show clearly on the graph how you obtained your answer.
..................................................................................................................................... [3]
(d) What type of chemical reaction occurs when aqueous potassium chloride reacts with
aqueous lead nitrate?
..................................................................................................................................... [1]
(e) (i) Compare the heights of the solids in test-tubes E and F.
.............................................................................................................................. [1]
(ii) Suggest an explanation for the heights of the solids in (e)(i).
....................................................................................................................................
.............................................................................................................................. [1]

10
For
(f) Predict what would happen if the experiment were continued using three further test- Examiner’s
tubes with 8 cm3, 9 cm3 and 10 cm3 of aqueous potassium chloride. Explain your answer. Use
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(g) What difference would be observed if the experiment was repeated using aqueous silver
nitrate and aqueous potassium iodide?
...........................................................................................................................................
..................................................................................................................................... [1]
(h) Explain one improvement the student could make to the experiment to obtain more
accurate results.
improvement .....................................................................................................................
explanation .......................................................................................................................
..................................................................................................................................... [2]
[Total: 19]
© UCLES 2012 0620/61/M/J/12

11
For
5 Solid W was analysed. W was a carbonate salt. Examiner’s
The tests on solid W, and some of the observations, are in the following table. Complete the Use
observations in the table.
Do not write any conclusions in the table.
tests observations
tests on solid W
(a) Appearance of solid W. white solid
(b) Solid W was heated. gas evolved formed a white solid at the top
of the test-tube
The gas given off was tested with damp

red litmus paper. litmus paper turned blue
(c) Dilute hydrochloric acid was added to

solid W. ..................................................................
The gas given off was tested. ..................................................................
........................................................... [3]
(d) Dilute sodium hydroxide was added to

solid W and the mixture heated. pungent gas given off
The gas given off was tested with damp pH of gas = 10

pH indicator paper.
(e) Identify the gas given off in test (d).
..................................................................................................................................... [1]
(f) What conclusions can you draw about solid W?
..................................................................................................................................... [2]
[Total: 6]

12
For
6 Examiner’s
STOP RUST! Use
Solutions of chemicals known as corrosion inhibitors are added to the water in steel radiators
to reduce rust.
You are provided with three different bottles of liquid corrosion inhibitors, R, S and T, and
some steel nails.
Plan an experiment to test if these inhibitors prevent the corrosion of steel and which of these
inhibitors is the most effective.
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
............................................................................................................................................ [7]
[Total: 7]
© UCLES 2012 0620/61/M/J/12


0620 CHEMISTRY
examination.
syllabuses.
1 (a) tripod (1) accept: stand spatula (1) not: spoon [2]
(b) fizz/bubbles/effervescence stops (1)

solid/iron/powder visible / no more iron dissolves/reacts (1) [2]
(c) evaporation of water/steam (1) solid/residue/crystals formed (1)

colour change turns brown/darker green (1)
effect of heat on solid solid breaks down (1) max 3 [3]
[Total: 7]
2 (a) thermometer readings correct (3), –1 for any incorrect

methanol 25 28 3
ethanol 26 39 13
propanol 23 46 23
butanol 24 58 34
temperature rises correct (1) [4]
(b) points plotted correctly ±1/2 small square (3)

straight line drawn with a ruler (1) [4]
(c) value from graph (1) unit (1) 44°C

extrapolation shown on grid (1) [3]
(d) temperature rises would be greater/faster/quicker (1)

copper is a good conductor (1) [2]
[Total: 13]
3 (a) pestle (1) mortar (1) [2]
(b) stir/mix/shake (1) allow: heat/boil [1]
(c) diagram showing funnel (1)

indication of filter paper (1) note: labels not necessary [2]
(d) heat/evaporation (1)

to crystallising point or description (1)
in fume cupboard (1) max 2 [2]
(e) melting point/description of (1) allow: chromatography ignore: bp [1]
[Total: 8]

4 (a) Table of results ignore: units in table

volume of aqueous potassium chloride boxes completed correctly (1) 1, 2, 4. 5, 6, 7
heights of solid boxes completed ±1mm (2) 4, 8, 16, 20, 24, 24
in mm (1) [4]
(b) all points correctly plotted (2), –1 for any incorrect

straight line graphs (2) note: one for each line, doesn’t have to go through origin [4]
(c) value from graph 14 (1) unit (1) shown clearly (1) [3]
(d) precipitation (1) allow: double decomposition ignore: exo/endothermic [1]
(e) (i) same (1) no ecf not: almost the same

all lead nitrate reacted/reaction finished/lead nitrate is limiting factor (1) [2]
(ii) same heights/owtte (1)

lead nitrate is limiting factor/same amount of lead nitrate/excess potassium chloride (1)
[2]
(g) yellow (precipitate) (1) [1]
(h) improvement (1) e.g. use burette/pipette/leave solid to settle longer/repeat

explanation (1) e.g. instead of a measuring cylinder/heights more accurate/take average [2]
[Total: 19]
5 (c) fizz/bubbles/effervescence (1) limewater (1)

milky/cloudy/white ppt (1) cond: on limewater [3]
(e) ammonia (1) [1]
(f) non-transition metal (1)

ammonium (salt or carbonate) (2) not: ammonia max [2]
[Total: 6]
6 steel nail(s) in test-tube/suitable glass container (1)

x cm3 (1)
water (1) no water = max 3
known volume of inhibitor added (1)
observe effect after suitable time (1) note: minimum time = 1 day
repeat using other inhibitors (1)
observe/comparison of results (1) [7]
[Total: 7]

CHEMISTRY 0620/11
45 Minutes
Soft clean eraser
*9639789716*

IB13 06_0620_11/RP
2
1 The diagram shows a cup of tea.
Which row describes the water particles in the air above the cup compared with the water
particles in the cup?
moving faster closer together
A
B
C
D
2 Crystals of sodium chloride were prepared by the following method.
1 25.0 cm3 of dilute hydrochloric acid was accurately measured into a conical flask.
2 Aqueous sodium hydroxide was added until the solution was neutral. The volume of
sodium hydroxide added was measured.
3 The solution was evaporated and the crystals washed with approximately 15 cm3 of
water.
Which row shows the pieces of apparatus used to measure the 25.0 cm3 of hydrochloric acid, the
volume of aqueous sodium hydroxide and the 15 cm3 of water?
25.0 cm3 of hydrochloric the volume of aqueous 15 cm3 of water

acid accurately sodium hydroxide added approximately
A burette pipette measuring cylinder

B measuring cylinder burette pipette
C pipette burette measuring cylinder
D pipette measuring cylinder burette
© UCLES 2013 0620/11/M/J/13

3
3 Lead iodide is insoluble in water.
Lead iodide is made by adding aqueous lead nitrate to aqueous potassium iodide.
Which pieces of apparatus are needed to obtain solid lead iodide from 20 cm3 of aqueous lead
nitrate?
1 2 3 4 5
A 1, 2 and 4 B 1, 3 and 5 C 1, 4 and 5 D 2, 4 and 5
27
4 Element X is represented by 13 X.
Which statement about element X is correct?
A An atom of X contains 13 protons and 13 neutrons.

B An atom of X contains 27 protons and 13 electrons.
C X forms an ion by gaining electrons.
D X is placed in Group III of the Periodic Table.
5 The positions of four elements are shown on the outline of the Periodic Table.
Which element forms a coloured oxide?
B C
D

4
6 For which substance is the type of bonding not correct?
type of bonding
substance
ionic covalent metallic
A chlorine
B potassium bromide
C sodium
D sodium chloride
7 Element X has six electrons in its outer shell.
e e key
e = electron
e
e
e e
How could the element react?
A by gaining two electrons to form a positive ion

B by losing six electrons to form a negative ion
C by sharing two electrons with two electrons from another element to form two covalent bonds
D by sharing two electrons with two electrons from another element to form four covalent bonds
8 The diagram shows an incomplete circuit.
lamp
glass tube
Which substance causes the lamp to light when added to the glass tube?
A aqueous sodium chloride

B aqueous sugar
C solid sodium chloride
D solid sugar
© UCLES 2013 0620/11/M/J/13

5
9 A compound with the formula XF2 has a relative formula mass of 78.
What is element X?
A argon
B calcium
C neon
D zirconium
10 What is the balanced chemical equation for the reaction between calcium and water?
A Ca + H2O → CaOH + H2
B Ca + H2O → Ca(OH)2 + H2
C Ca + 2H2O → CaOH + H2
D Ca + 2H2O → Ca(OH)2 + H2
11 The diagram shows an electrical cable.
plastic coating
metal core
Which statement about the substances used is correct?
A The coating is plastic because it conducts electricity well.

B The core is copper because it conducts electricity well.
C The core is copper because it is cheap and strong.
D The core is iron because it is cheap and strong.

6
12 The diagram shows an electrolysis circuit.
At which electrode is hydrogen formed?
+ – + –
A B C D
aqueous molten
sodium sodium
chloride chloride
13 Some white anhydrous copper(II) sulfate powder is put into a beaker of water and stirred.
What would show that the process was exothermic?
A A blue solution is formed.

B The beaker feels cooler.
C The beaker feels warmer.
D The powder dissolves in the water.
14 Which substance does not require oxygen in order to produce energy?
A coal
B hydrogen
C natural gas
235
D U
© UCLES 2013 0620/11/M/J/13

7
15 The equation shows the formation of anhydrous copper(II) sulfate from hydrated copper(II)
sulfate.
CuSO4.5H2O CuSO4 + 5H2O
Statements 1, 2 and 3 refer to this reaction.
1 Hydrated copper(II) sulfate is reduced to anhydrous copper(II) sulfate.
2 The (II) in the name copper(II) sulfate refers to the oxidation state of the metal.
3 The reaction is reversible.
A 1 only B 1 and 2 C 2 and 3 D 3 only
16 Calcium carbonate reacts with hydrochloric acid to form carbon dioxide.
Which changes would slow this reaction down?
1 decreasing the concentration of hydrochloric acid

2 decreasing the particle size of calcium carbonate
3 decreasing the temperature
17 The equations represent redox reactions.
In which equation is the underlined substance acting as a reducing agent?
A 3CO + Fe2O3 → 2Fe + 3CO2
B CO2 + C → 2CO
C CuO + H2 → Cu + H2O
D CaO + H2O → Ca(OH)2
18 Ant stings hurt because of the methanoic acid produced by the ant.
Which substance could, most safely, be used to neutralise the acid?
substance pH
A baking soda 8
B car battery acid 1
C lemon juice 3
D oven cleaner 14

8
19 The diagram shows one period of the Periodic Table.
Li Be B C N O F Ne
Which two elements form acidic oxides?
A carbon and lithium

B carbon and neon
C carbon and nitrogen
D nitrogen and neon
20 The diagram shows an experiment.
blue red
litmus paper litmus paper
aqueous
ammonium chloride
+
aqueous
sodium hydroxide
heat
What happens to the pieces of litmus paper?
blue litmus paper red litmus paper
A changes colour changes colour

B changes colour no colour change
C no colour change changes colour
D no colour change no colour change
© UCLES 2013 0620/11/M/J/13

9
21 Two indicators, bromophenol blue and Congo red, show the following colours in acidic solutions
and in alkaline solutions.
indicator acid alkali
bromophenol blue yellow blue

Congo red violet red
A few drops of each indicator are added to separate samples of a solution of pH 2.
What are the colours of the indicators in this solution?
in a solution of pH 2
bromophenol blue is Congo red is
A blue red
B blue violet
C yellow red
D yellow violet
22 Which property of elements increases across a period of the Periodic Table?
A metallic character
B number of electron shells
C number of outer shell electrons
D tendency to form positive ions
23 Which element is a transition metal?
colour of melting point of

chloride element / °C
A white 113
B white 1495
C yellow 113
D yellow 1495

10
24 Fluorine is at the top of Group VII in the Periodic Table.
Which row shows the properties of fluorine?
state at room reaction with aqueous

colour
temperature potassium iodide
A brown gas no reaction

B brown liquid iodine displaced
C yellow gas iodine displaced
D yellow liquid no reaction
25 Group I metals are also known as the Alkali Metals.
Which statement about the metals in Group I is not correct?
A In their reactions they lose electrons.

B Their atoms all have one electron in their outer shell.
C They form +1 ions in their reactions with non-metals.
D They form covalent compounds by sharing electrons.
26 Which element is a metal?
charge on electrical
element ion conductivity
A negative low
B positive high
C negative high
D positive low
27 Which property makes aluminium ideal for making food containers?
A conducts electricity
B conducts heat
C mechanical strength
D resistance to corrosion
© UCLES 2013 0620/11/M/J/13

11
28 Which substance is not involved in the extraction of iron from hematite?
A carbon
B carbon monoxide
C calcium carbonate
D nitrogen
29 Pure metals conduct electricity and can be hammered into different shapes.
Why are metals sometimes used as alloys?
A Alloys are cheaper than the metals they are made from.
B Alloys are easier to hammer into different shapes.
C Alloys are harder and keep their shape better.
D Alloys conduct electricity better.
30 Below are some metals in decreasing order of reactivity.
magnesium
zinc
iron
copper
Titanium reacts with acid and cannot be extracted from its ore by heating with carbon.
Where should titanium be placed in this list?
A below copper
B between iron and copper
C between magnesium and zinc
D between zinc and iron
31 Water has been contaminated with sea-water.
Which substances can be removed by chlorination and filtration?
A bacteria, sand and sodium chloride

B bacteria and sand only
C bacteria and sodium chloride only
D sand and sodium chloride only

12
32 Iron rusts when it reacts with ……1……
Rusting can be prevented by covering the iron with a more reactive metal, such as ……2……
1 2
A oxygen copper
B oxygen magnesium
C oxygen and water copper
D oxygen and water magnesium
33 Nitrogen, phosphorus and potassium are essential elements for plant growth.
Which mixture provides all three essential elements?
mixture formula
A ammonium phosphate (NH4)3PO4

+ +
potassium chloride KCl
B ammonium phosphate (NH4)3PO4

+ +
ammonium nitrate NH4NO3
C ammonium phosphate (NH4)3PO4

+ +
ammonium chloride NH4Cl
D ammonium nitrate NH4NO3

+ +
34 Which information about carbon dioxide and methane is correct?
carbon dioxide methane
A formed when vegetation decomposes key

B greenhouse gas = true
C present in unpolluted air = false
D produced during respiration
© UCLES 2013 0620/11/M/J/13

13
35 The list shows four methods that were suggested for the formation of carbon dioxide.
1 action of an alkali on a carbonate

2 action of heat on a carbonate
3 complete combustion of methane
4 reaction of a carbonate with oxygen
Which methods would result in the production of carbon dioxide?
36 Organic compounds may have names ending in -ane, -ene, -ol or -oic acid.
How many of these endings indicate the compounds contain double bonds in their molecules?
A 1 B 2 C 3 D 4
37 The table shows the boiling points of four members of the homologous series of alcohols.
compound boiling point

name formula / °C
methanol CH3OH 65
ethanol C2H5OH 78
propanol C3H7OH X
butanol C4H9OH 117
What is the value of X?
A 55 °C B 82 °C C 98 °C D 115 °C

14
38 The table shows some fractions that are obtained from petroleum by fractional distillation,
together with some of their uses.
fraction use
refinery gas cooking

gasoline fuel for cars
1 making chemicals
2 jet fuel
3 fuel for ships
bitumen making roads
Which row correctly identifies fractions 1, 2 and 3?
1 2 3
A diesel oil fuel oil lubricating fraction

B fuel oil diesel oil kerosene
C kerosene naphtha diesel oil
D naphtha kerosene fuel oil
39 Which columns describe the hydrocarbons ethane and ethene?
1 2 3 4
state at room temperature gas gas liquid liquid

reaction with oxygen burns burns burns burns
reaction with aqueous decolourises decolourises
no reaction no reaction
bromine bromine bromine
A 1 (ethane) and 2 (ethene)

B 1 (ethane) and 4 (ethene)
C 2 (ethene) and 3 (ethane)
D 3 (ethane) and 4 (ethene)
40 Which of the statements about ethanol are correct?
1 Ethanol can be formed by an addition reaction.

2 Ethanol can be formed by fermentation.
3 When ethanol burns in air, it forms carbon dioxide and water.
A 1, 2 and 3 B 1 and 2 C 1 and 3 D 2 and 3
© UCLES 2013 0620/11/M/J/13

15
BLANK PAGE
© UCLES 2013 0620/11/M/J/13

© UCLES 2013
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/11/M/J/13
Indium Iodine
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
CAMBRIDGE INTERNATIONAL EXAMINATIONS
MARK SCHEME for the May/June 2013 series
0620 CHEMISTRY
Mark schemes should be read in conjunction with the question paper and the Principal Examiner
Report for Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2013 series for most IGCSE, GCE
Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components.
Page 2 Mark Scheme Syllabus Paper
Question Question
Key Key
Number Number
1 B 21 D
2 C 22 C
3 C 23 D
4 D 24 C
5 D 25 D
6 D 26 B
7 C 27 D
8 A 28 D
9 B 29 C
10 D 30 C
11 B 31 B
12 B 32 D
13 C 33 A
14 D 34 B
15 C 35 C
16 B 36 B
17 A 37 C
18 A 38 D
19 C 39 A
20 C 40 A
© Cambridge International Examinations 2013

CHEMISTRY 0620/11
45 Minutes
Soft clean eraser
*9639789716*

IB13 06_0620_11/RP
2
1 The diagram shows a cup of tea.
A
B
C
D
2 Crystals of sodium chloride were prepared by the following method.
1 25.0 cm3 of dilute hydrochloric acid was accurately measured into a conical flask.
2 Aqueous sodium hydroxide was added until the solution was neutral. The volume of
sodium hydroxide added was measured.
3 The solution was evaporated and the crystals washed with approximately 15 cm3 of
water.
Which row shows the pieces of apparatus used to measure the 25.0 cm3 of hydrochloric acid, the
volume of aqueous sodium hydroxide and the 15 cm3 of water?
25.0 cm3 of hydrochloric the volume of aqueous 15 cm3 of water

acid accurately sodium hydroxide added approximately
A burette pipette measuring cylinder

B measuring cylinder burette pipette
C pipette burette measuring cylinder
D pipette measuring cylinder burette
© UCLES 2013 0620/11/M/J/13

3
3 Lead iodide is insoluble in water.
Lead iodide is made by adding aqueous lead nitrate to aqueous potassium iodide.
Which pieces of apparatus are needed to obtain solid lead iodide from 20 cm3 of aqueous lead
nitrate?
1 2 3 4 5
27
4 Element X is represented by 13 X.
Which statement about element X is correct?
A An atom of X contains 13 protons and 13 neutrons.

B An atom of X contains 27 protons and 13 electrons.
C X forms an ion by gaining electrons.
D X is placed in Group III of the Periodic Table.
5 The positions of four elements are shown on the outline of the Periodic Table.
Which element forms a coloured oxide?
B C
D

4
6 For which substance is the type of bonding not correct?
type of bonding
substance
ionic covalent metallic
A chlorine
B potassium bromide
C sodium
D sodium chloride
7 Element X has six electrons in its outer shell.
e e key
e = electron
e
e
e e
How could the element react?
A by gaining two electrons to form a positive ion

B by losing six electrons to form a negative ion
C by sharing two electrons with two electrons from another element to form two covalent bonds
D by sharing two electrons with two electrons from another element to form four covalent bonds
8 The diagram shows an incomplete circuit.
lamp
glass tube
Which substance causes the lamp to light when added to the glass tube?
A aqueous sodium chloride

B aqueous sugar
C solid sodium chloride
D solid sugar
© UCLES 2013 0620/11/M/J/13

5
9 A compound with the formula XF2 has a relative formula mass of 78.
What is element X?
A argon
B calcium
C neon
D zirconium
10 What is the balanced chemical equation for the reaction between calcium and water?
A Ca + H2O → CaOH + H2
B Ca + H2O → Ca(OH)2 + H2
C Ca + 2H2O → CaOH + H2
D Ca + 2H2O → Ca(OH)2 + H2
plastic coating
metal core


6
12 The diagram shows an electrolysis circuit.
At which electrode is hydrogen formed?
+ – + –
A B C D
aqueous molten
sodium sodium
chloride chloride
13 Some white anhydrous copper(II) sulfate powder is put into a beaker of water and stirred.
What would show that the process was exothermic?
A A blue solution is formed.

B The beaker feels cooler.
C The beaker feels warmer.
D The powder dissolves in the water.
14 Which substance does not require oxygen in order to produce energy?
A coal
B hydrogen
C natural gas
235
D U
© UCLES 2013 0620/11/M/J/13

7
15 The equation shows the formation of anhydrous copper(II) sulfate from hydrated copper(II)
sulfate.
Statements 1, 2 and 3 refer to this reaction.
1 Hydrated copper(II) sulfate is reduced to anhydrous copper(II) sulfate.
2 The (II) in the name copper(II) sulfate refers to the oxidation state of the metal.
3 The reaction is reversible.
A 1 only B 1 and 2 C 2 and 3 D 3 only
16 Calcium carbonate reacts with hydrochloric acid to form carbon dioxide.
Which changes would slow this reaction down?
1 decreasing the concentration of hydrochloric acid

2 decreasing the particle size of calcium carbonate
3 decreasing the temperature
17 The equations represent redox reactions.
In which equation is the underlined substance acting as a reducing agent?
A 3CO + Fe2O3 → 2Fe + 3CO2
B CO2 + C → 2CO
D CaO + H2O → Ca(OH)2
18 Ant stings hurt because of the methanoic acid produced by the ant.
Which substance could, most safely, be used to neutralise the acid?
substance pH
A baking soda 8
B car battery acid 1
C lemon juice 3
D oven cleaner 14

8
19 The diagram shows one period of the Periodic Table.
Li Be B C N O F Ne
Which two elements form acidic oxides?
A carbon and lithium

B carbon and neon
C carbon and nitrogen
D nitrogen and neon
20 The diagram shows an experiment.
blue red
litmus paper litmus paper
aqueous
ammonium chloride
+
aqueous
sodium hydroxide
heat
What happens to the pieces of litmus paper?
blue litmus paper red litmus paper
A changes colour changes colour

B changes colour no colour change
C no colour change changes colour
D no colour change no colour change
© UCLES 2013 0620/11/M/J/13

9
21 Two indicators, bromophenol blue and Congo red, show the following colours in acidic solutions
and in alkaline solutions.
indicator acid alkali
bromophenol blue yellow blue

Congo red violet red
A few drops of each indicator are added to separate samples of a solution of pH 2.
What are the colours of the indicators in this solution?
in a solution of pH 2
bromophenol blue is Congo red is
A blue red
B blue violet
C yellow red
D yellow violet
22 Which property of elements increases across a period of the Periodic Table?
A metallic character
C number of outer shell electrons
D tendency to form positive ions
23 Which element is a transition metal?

A white 113
B white 1495
C yellow 113
D yellow 1495

10
24 Fluorine is at the top of Group VII in the Periodic Table.
Which row shows the properties of fluorine?
state at room reaction with aqueous

colour
temperature potassium iodide
A brown gas no reaction

B brown liquid iodine displaced
C yellow gas iodine displaced
D yellow liquid no reaction
25 Group I metals are also known as the Alkali Metals.
Which statement about the metals in Group I is not correct?
A In their reactions they lose electrons.

B Their atoms all have one electron in their outer shell.
C They form +1 ions in their reactions with non-metals.
D They form covalent compounds by sharing electrons.
26 Which element is a metal?
charge on electrical
element ion conductivity
A negative low
B positive high
C negative high
D positive low
27 Which property makes aluminium ideal for making food containers?
A conducts electricity
B conducts heat
C mechanical strength
D resistance to corrosion
© UCLES 2013 0620/11/M/J/13

11
28 Which substance is not involved in the extraction of iron from hematite?
A carbon
B carbon monoxide
C calcium carbonate
D nitrogen
29 Pure metals conduct electricity and can be hammered into different shapes.
Why are metals sometimes used as alloys?
A Alloys are cheaper than the metals they are made from.
B Alloys are easier to hammer into different shapes.
C Alloys are harder and keep their shape better.
D Alloys conduct electricity better.
30 Below are some metals in decreasing order of reactivity.
magnesium
zinc
iron
copper
Where should titanium be placed in this list?
A below copper
31 Water has been contaminated with sea-water.
Which substances can be removed by chlorination and filtration?
A bacteria, sand and sodium chloride

B bacteria and sand only
C bacteria and sodium chloride only
D sand and sodium chloride only

12
32 Iron rusts when it reacts with ……1……
Rusting can be prevented by covering the iron with a more reactive metal, such as ……2……
1 2
A oxygen copper
B oxygen magnesium
C oxygen and water copper
D oxygen and water magnesium
33 Nitrogen, phosphorus and potassium are essential elements for plant growth.
Which mixture provides all three essential elements?
mixture formula
A ammonium phosphate (NH4)3PO4

+ +
B ammonium phosphate (NH4)3PO4

+ +
ammonium nitrate NH4NO3
C ammonium phosphate (NH4)3PO4

+ +
ammonium chloride NH4Cl
D ammonium nitrate NH4NO3

+ +

© UCLES 2013 0620/11/M/J/13

13
35 The list shows four methods that were suggested for the formation of carbon dioxide.
1 action of an alkali on a carbonate

2 action of heat on a carbonate
3 complete combustion of methane
4 reaction of a carbonate with oxygen
Which methods would result in the production of carbon dioxide?
36 Organic compounds may have names ending in -ane, -ene, -ol or -oic acid.
How many of these endings indicate the compounds contain double bonds in their molecules?
A 1 B 2 C 3 D 4
37 The table shows the boiling points of four members of the homologous series of alcohols.
compound boiling point

name formula / °C
methanol CH3OH 65
ethanol C2H5OH 78
propanol C3H7OH X
butanol C4H9OH 117
What is the value of X?
A 55 °C B 82 °C C 98 °C D 115 °C

14
38 The table shows some fractions that are obtained from petroleum by fractional distillation,
together with some of their uses.
fraction use
refinery gas cooking

gasoline fuel for cars
1 making chemicals
2 jet fuel
3 fuel for ships
bitumen making roads
Which row correctly identifies fractions 1, 2 and 3?
1 2 3
A diesel oil fuel oil lubricating fraction

B fuel oil diesel oil kerosene
C kerosene naphtha diesel oil
D naphtha kerosene fuel oil
39 Which columns describe the hydrocarbons ethane and ethene?
1 2 3 4
state at room temperature gas gas liquid liquid

reaction with oxygen burns burns burns burns
reaction with aqueous decolourises decolourises
no reaction no reaction
bromine bromine bromine
A 1 (ethane) and 2 (ethene)

B 1 (ethane) and 4 (ethene)
C 2 (ethene) and 3 (ethane)
D 3 (ethane) and 4 (ethene)
40 Which of the statements about ethanol are correct?
1 Ethanol can be formed by an addition reaction.

2 Ethanol can be formed by fermentation.
3 When ethanol burns in air, it forms carbon dioxide and water.
A 1, 2 and 3 B 1 and 2 C 1 and 3 D 2 and 3
© UCLES 2013 0620/11/M/J/13

15
BLANK PAGE
© UCLES 2013 0620/11/M/J/13

© UCLES 2013
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/11/M/J/13
Indium Iodine
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
*0286058287*
CHEMISTRY 0620/21
1 hour 15 minutes

IB13 06_0620_21/2RP
2
For
1 The electronic structures of five atoms of different elements, A, B, C, D and E, are shown Examiner’s
below. Use
A B C D E
Answer the following questions about these structures. Each structure may be used once,
more than once or not at all.
(a) Which structure
(i) is in Period 4 of the Periodic Table,
(ii) is a noble gas,
(iii) is in Group II of the Periodic Table,
(iv) has five electrons in its outer shell,
(v) has a proton (atomic) number of 7,
(vi) represents a fluorine atom? [6]
(b) Complete the following sentences about elements using words from the list below.
alkali atom covalent ion
monatomic three transition two
An element is a substance containing only one type of .......................... .
The Group VII elements exist as molecules containing .......................... atoms.
Carbon has a giant .......................... structure with many strong bonds.
Elements such as iron and copper, which form coloured compounds, are called
.......................... elements. [4]
[Total: 10]
© UCLES 2013 0620/21/M/J/13

3
For
2 The table below shows some properties of the Group I elements. Examiner’s
Use
metal density in g / cm3 melting point / °C boiling point / °C

lithium 0.53 181 1342
sodium 0.97 98 883
potassium 0.86 63
rubidium 1.53 39 686
caesium 1.88 29 669
(a) Use the information in the table to explain why caesium is a liquid when the temperature
is 34 °C.
...........................................................................................................................................
..................................................................................................................................... [1]
(b) Suggest a value for the boiling point of potassium.
.................. °C [1]
(c) (i) Describe the general trend in density down the group.
.............................................................................................................................. [1]
(ii) Which element does not follow this trend?
.............................................................................................................................. [1]
(d) State three physical properties of potassium, other than density, melting point and boiling
point.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(e) Potassium reacts with water. The products are potassium hydroxide and hydrogen.
(i) Describe two observations when potassium reacts with water.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Complete the symbol equation for this reaction.
2K + ......H2O → 2KOH + ......... [2]
[Total: 11]

4
For
3 (a) Match the name of the homologous series on the left with its formula on the right. Examiner’s
The first one has been done for you. Use
halogenoalkane C2H 6
alkane CH3COOH
alkene C2H5OH
alcohol C2H5Cl
carboxylic acid C2H 4
[4]
(b) Draw the full structural formula of the compound, C2H6, showing all atoms and bonds.
[1]
(c) The compound with the formula C2H4 is an unsaturated hydrocarbon.

Describe the difference between a saturated and an unsaturated hydrocarbon in terms
of the bonds they contain.
...........................................................................................................................................
..................................................................................................................................... [2]
(d) Describe a test to distinguish between a saturated and unsaturated hydrocarbon.
test ....................................................................................................................................
result with saturated hydrocarbon ....................................................................................
...........................................................................................................................................
result with unsaturated hydrocarbon ................................................................................
..................................................................................................................................... [3]
[Total: 10]
© UCLES 2013 0620/21/M/J/13

5
For
4 Farmers spread fertilisers on the soil where crops are to be grown. Examiner’s
Use
(a) Why do farmers use fertilisers? In your answer, include
● the names of the essential elements present in most fertilisers,

● the reasons why farmers use fertilisers.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(b) Urea can be used as a fertiliser.

The structure of urea is shown below.
H H
H N N H
C
(i) Deduce the molecular formula of urea.
.............................................................................................................................. [1]
(ii) Calculate the relative molecular mass of urea. You must show all your working.
[2]

6
For
(c) Urea is a solid at room temperature. Complete the diagram below to show the arrangement Examiner’s
of the molecules in solid urea. Use
Show a molecule of urea as
[2]
(d) When urea is heated with an alkali, ammonia is given off.

Describe a test for ammonia.
test ....................................................................................................................................
result ........................................................................................................................... [2]
[Total: 11]
© UCLES 2013 0620/21/M/J/13

7
For
5 The table shows some properties of four substances, A, B, C and D. Examiner’s
Use
does a solution of
does the solid
substance melting point / °C the solid conduct
conduct electricity?
electricity?
A 962 yes does not dissolve

B 747 no dissolves and conducts
C 113 no does not dissolve
D 3550 no does not dissolve
(a) Which one of these substances has
(i) a giant covalent structure,
(ii) a simple molecular structure,
(iii) a metallic structure? [3]
(b) A student carried out an experiment to determine the rate of reaction of calcium carbonate
with excess hydrochloric acid.
CaCO3(s) + 2HCl (aq) → CaCl 2(aq) + CO2(g) + H2O(l)
He recorded the loss of mass of the reaction mixture over a period of time.
cotton wool
small pieces of
hydrochloric acid calcium carbonate
balance
362.05
(i) Explain why the reaction mixture decreases in mass.
.............................................................................................................................. [1]

8
For
He carried out the reaction at constant temperature using 2 g of calcium carbonate in Examiner’s
small pieces. The hydrochloric acid was in excess. Use
He plotted his results on a grid. This is shown below.
1.0
0.8
0.6
loss in
mass / g
0.4
0.2
0
0 100 200 300 400 500 600
time / seconds
(ii) At what time has the reaction just finished?
................... s [1]
(iii) From the graph, deduce the loss in mass in the first 100 seconds.
................... g [1]
(iv) The student repeated the experiment keeping everything the same except for the
size of the pieces of calcium carbonate. He used smaller pieces of calcium carbonate
but the mass used was the same.
On the grid above, draw a line to show how the loss of mass changes with time when
smaller pieces of calcium carbonate are used. [2]
(v) State the effect of increasing the concentration of hydrochloric acid on the rate
(speed) of this reaction when all other factors remain constant.
.............................................................................................................................. [1]
[Total: 9]
© UCLES 2013 0620/21/M/J/13

9
For
6 (a) Propanol is a solvent. Examiner’s
Sugar is soluble in propanol. Salt (sodium chloride) is insoluble in propanol. Use
A student wants to separate a mixture of solid salt and solid sugar.
(i) Describe how she could separate the salt from the sugar.
You may draw a labelled diagram to help you answer this question.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]
(ii) Describe how the student could obtain solid sodium chloride from a solution of
sodium chloride in water.
.............................................................................................................................. [1]
(b) The diagram shows the structure of sodium chloride.
Na+ Cl – Na+ Cl –
Cl – Na+ Cl – Na+
(i) Deduce the simplest formula for sodium chloride.
.............................................................................................................................. [1]
(ii) What type of bonding is present in sodium chloride?

covalent ionic metallic weak [1]

10
For
(c) The diagram shows the apparatus used to electrolyse a concentrated aqueous solution Examiner’s
of sodium chloride. Use
+ –
B C
(i) Which letter on the diagram, A, B, C or D, represents the electrolyte?
.............................................................................................................................. [1]
(ii) Name the product formed at
the positive electrode, ................................................................................................
the negative electrode. ........................................................................................ [2]
[Total: 9]
© UCLES 2013 0620/21/M/J/13

11
For
7 (a) A student set up the apparatus shown below. Examiner’s
The concentrated hydrochloric acid gives off hydrogen chloride gas. Use
After 15 seconds, the damp blue litmus paper begins to turn red.
After 25 seconds, the litmus paper has turned completely red.
damp blue
litmus paper slightly red all red
long glass tube
cotton wool soaked

in concentrated
hydrochloric acid
at the start after 15 seconds after 25 seconds
Use ideas about moving particles to explain these observations.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(b) Hydrogen chloride reacts with ammonia to form a salt which has the formula NH4Cl.
State the name of this salt.
..................................................................................................................................... [1]
(c) (i) Hydrochloric acid reacts with iron to form iron(II) chloride and hydrogen.
Write a word equation for this reaction.
.............................................................................................................................. [1]
(ii) Describe a test for iron(II) ions.
test .............................................................................................................................
result .................................................................................................................... [2]

12
For
(d) A student investigates various methods of protecting iron from rusting. She sets up four Examiner’s
tubes as shown in the diagram below. Use
tube 1 tube 2 tube 3 tube 4
oil
iron
nail
water water water
iron iron iron iron

completely incompletely
coated with coated with
plastic plastic
(i) Tube 1 contains unprotected iron. What is the purpose of this experiment?
.............................................................................................................................. [1]
(ii) State the names of the two substances needed for iron to rust.
.......................................................... and .......................................................... [2]
(iii) Explain why the iron in tube 4 does not rust.
....................................................................................................................................
.............................................................................................................................. [1]
(iv) Explain why the iron in tube 3 eventually rusts.
....................................................................................................................................
.............................................................................................................................. [1]
[Total: 13]
© UCLES 2013 0620/21/M/J/13

13
For
8 The diagram shows a silvered light bulb. Examiner’s
Use
thin layer of
thin coil of
silver alloy
tungsten wire
brass
lamp holder plastic
copper wires
Some properties of metals used in the light bulb are shown in the table below.
electrical melting point price

metal hardness
conductivity / °C / $ per tonne
brass hard good about 1000 7 000

copper fairly soft very good 1083 9 600
silver fairly soft very good 962 1 300 000
tungsten hard good 3410 450
(a) (i) Suggest why copper rather than tungsten is used for electrical wiring?
.............................................................................................................................. [1]
(ii) Suggest why silver is not used for electrical wiring.
.............................................................................................................................. [1]
(iii) Suggest two reasons why tungsten rather than copper is used to make the bulb
filament.
reason 1 .....................................................................................................................
reason 2 ............................................................................................................... [2]
(iv) Explain why the copper wires are covered with plastic.
....................................................................................................................................
.............................................................................................................................. [2]

14
For
(b) Brass is an alloy. Examiner’s
Which one of the following diagrams, A, B, C or D, best represents an alloy? Use
A B C D
..................................................................................................................................... [1]
[Total: 7]
© UCLES 2013 0620/21/M/J/13

15
BLANK PAGE
© UCLES 2013 0620/21/M/J/13

© UCLES 2013
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/21/M/J/13
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY
1 (a) (i) E [1]
(ii) B [1]
(iii) E [1]
(iv) A [1]
(v) A [1]
(vi) D [1]
(b) 1 mark for each correct word

atom;
two;
covalent ALLOW: atom;
transition; [4]
[Total: 10]
2 (a) melting point below (34 °C) and boiling point above (34 °C) [1]
ALLOW: its melting point is 29 °C and its boiling point is 669 °C
(b) ALLOW: 740–800 °C (actual is 760 °C)` [1]
(c) (i) increases (down the group) [1]

ALLOW: goes up / goes up except for potassium
(ii) sodium / Na [1]
(d) 1 mark for each of:
• shiny (when freshly cut) ALLOW: silvery / silver colour

• conducts heat / conducts electricity / conducts
• ductile / can be drawn into wires
• malleable / can be shaped ALLOW: can be bent
• ALLOW: solid at room temperature
• soft (for 1 mark) [3]
IGNORE: sonorous / it is a metal

(e) (i) Any two of:
• bubbles
• moves (around)
• floats / on surface
• catches fire / flame
• lilac (flame) ALLOW: mauve or purple
• explodes / spits
• fizzing
• forms a ball
• beaker gets hotter
• gets smaller [2]
IGNORE: water goes cloudy / water goes purple or blue
(ii) H2 on right; [1]

2 on left (dependent on H2 or 2H on right) [1]
[Total: 11]
3 (a) 1 mark for each correct line / indication
alkane → C2H6
alkene → C2H4
alcohol → C2H5OH
carboxylic acid → CH3COOH [4]
(b) Full structural formula shown i.e.
H H
| |
H–C–C–H
| |
H H [1]
ALLOW: correct dot and cross diagram
(c) saturated has only single bonds / no double bonds; [1]
unsaturated has double bond(s) [1]

IGNORE: one has single bonds and the other has double bonds

(d) bromine water / aqueous bromine / bromine / ALLOW: correct formula; [1]
IGNORE: Br
(saturated hydrocarbon) no reaction / stays the same colour / remains orange / remains
orange-brown [1]
ALLOW: remains brown
ALLOW: remains yellow (if aqueous bromine used) / remains red (if bromine used)
IGNORE: remains yellow (if bromine used)
REJECT: incorrect colour, e.g. stays same blue colour, does not score
(unsaturated hydrocarbon) decolourises / goes colourless [1]

IGNORE: goes clear
IGNORE: initial incorrect colour of bromine
(acidified) potassium permanganate / potassium manganate(VII) (1 mark)

goes colourless / purple to colourless (1 mark)
IF: incorrect reagent 0 for this question
[Total: 10]
4 (a) two marks for names of elements present: [2]

nitrogen + phosphorus + potassium (or correct symbols) = 2 marks
NOT: N2
any two of nitrogen, phosphorus or potassium (or symbols) = 1 mark
two marks for reasons: [2]

any two of:
• soil depleted of minerals / depleted of essential elements / depleted of any of N or P

or K
ALLOW: plants use up minerals / use up essential elements / use up N or P or K
• to increase the nitrogen or phosphorus or potassium in the soil
ALLOW: to increase the nitrates in the soil / to increase the phosphates in the soil
• increased growth / more growth / better growth (idea of more growth needed)
ALLOW: more rapid growth / quicker growth
ALLOW: produce more crops
IGNORE: produce more unqualified
IGNORE: for growth / to grow / to keep plants healthy / for healthier growth
• (for making) more protein
NOTE: to increase the nitrogen (or N) in the soil = 1

(0 mark for elements and 1 for increase of that element)
to increase the N + P in the soil = 2
(1 mark for two of the elements and one for idea of increase)
(b) (i) CON2H4 [1]

ALLOW: any order
(ii) 60 [2]
if 2 marks not scored: ALLOW 1 mark for correct atomic masses
N = 14, O = 16, H = 1, C = 12 anywhere in working
NOTE: no e.c.f.

(c) regular arrangement; [1]

NOTE: minimum of 2 rows of 3 molecules required
molecules touching each other [1]

NOTE: minimum of 6 (O) are required all of which are touching or very close together.
REJECT: molecules in a single row touching
(d) (damp red) litmus (paper); [1]

ALLOW: pH paper
turns blue [1]

NOTE: second mark dependent on first being correct
ALLOW: universal indicator / full range indicator (paper) (1 mark)

turns purple / blue (1 mark)
ALLOW: hydrochloric acid (1) gives white fumes (1)
[Total: 11]
5 (a) (i) D [1]
(ii) C [1]
(iii) A [1]
(b) (i) loss of carbon dioxide / loss of gas [1]
(ii) accept values from 360–380 [1]

ALLOW: 6 min to 6 min 20 s / 6 ⅓ min
(iii) 0.5 (g) [1]
(iv) (initial) gradient greater / slope greater and starts at 0, 0; [1]

same final volume [1]
(v) (rate) increases [1]

IGNORE: more carbon dioxide per second
ALLOW : (rate) faster
[Total: 9]
6 (a) (i) Any three of: [3]
• add propanol to the mixture and shake (or stir)

• implication of filtration of solution / diagram of filter funnel and filter paper
REJECT: diagram of filter paper circle on top of funnel
• sugar solution goes through the filter paper / sugar solution is the
filtrate / diagram shows sugar solution (labelled) passing through filter paper
• salt or sodium chloride remains on filter paper / diagram shows salt or sodium
chloride (labelled) remaining on filter paper

(ii) evaporate the water / evaporation [1]

IGNORE: heat
ALLOW: distillation
(b) (i) NaCl [1]

ALLOW: Na+Cl –
REJECT: Na+ + Cl – / multiples, e.g. 2NaCl
(ii) ionic [1]
(c) (i) D [1]
(ii) positive electrode → chlorine / Cl2 [1]

IGNORE: Cl
negative electrode → hyrdrogen / H2 [1]

IGNORE: H
IF: correct electrode products reversed = 1 mark
[Total: 9]
7 (a) Any four of:
• evaporates or evaporation (of hydrogen chloride)

• movement of particles
• hydrogen chloride particles (move) / HCl particles (move)
ALLOW: hydrochloric acid particles (move)
• diffusion
• particles collide (with each other)
• spreading out of particles
• random (movement of particles)
• HCl particles hit litmus
• ALLOW: (HCl ) particles (move from higher) to lower concentration
ALLOW: molecules or atoms in place of particles
NOTE: no mark for acid turning damp blue litmus red

NOTE: hydrogen chloride particles move = 2 mark
NOTE: random movement of hydrogen chloride particles = 3 marks [4]
(b) ammonium chloride [1]

REJECT: ammonia chloride

(c) (i) iron + hydrochloric acid → iron(II) chloride + hydrogen [1]

IGNORE: symbol equation
REJECT: iron chloride
(ii) add sodium hydroxide (solution / aqueous) ammonia; [1]

ALLOW: add ammonium hydroxide
greyish-green precipitate [1]

ALLOW: green ppt.
IGNORE: what happens in excess reagent
NOTE: second mark dependent on first being correct
(d) (i) control / standard / idea of making fair comparison [1]
(ii) water / H2O [1]
air / oxygen / O2 [1]

IGNORE: O
APPLY: listing for other incorrect substances
(iii) air not present / oxygen not present / water not present [1]
(iv) air and water can get to the surface of the iron / oxygen and water can get to the
iron [1]
IGNORE: ideas that not all surface is protected
[Total: 13]
8 (a) (i) better conductor ORA [1]

IGNORE: it conducts / good conductor
IGNORE: it is softer / easier to draw into wire
(ii) too expensive / higher cost [1]

IGNORE: it has a low melting point
(iii) higher melting point; [1]

IGNORE: high melting point
cheaper [1]
(iv) (plastic) is an insulator; [1]

explanation of insulator, e.g. does not conduct electricity [1]
ALLOW: so you don’t get an electric shock
(b) B [1]
[Total: 7]

*2845008432*
CHEMISTRY 0620/31
1 hour 15 minutes

IB13 06_0620_31/2RP
2
For
1 Petroleum contains hydrocarbons which are separated by fractional distillation. Examiner’s
Use
(a) (i) Complete the following definition of a hydrocarbon.
A hydrocarbon is a compound which .........................................................................
.............................................................................................................................. [2]
(ii) Explain what is meant by the term fractional distillation.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(b) Some of the fractions obtained from petroleum are given below.
State a use for each fraction.
bitumen ....................................................................
lubricating fraction ...................................................
paraffin fraction ........................................................
gasoline fraction ...................................................... [4]
[Total: 8]
2 An element, M, has the electron distribution 2 + 8 + 18 + 3.
(a) Which group in the Periodic Table is element M likely to be in?
..................................................................................................................................... [1]
(b) Predict whether element M is a poor or a good conductor of electricity.

..................................................................................................................................... [1]
(c) Binary compounds contain two atoms per molecule, for example HCl.
Identify an element which could form a binary compound with element M.
..................................................................................................................................... [1]
(d) Predict the formula of the sulfate of M. The formula of the sulfate ion is SO42–.
..................................................................................................................................... [1]
© UCLES 2013 0620/31/M/J/13

3
For
(e) The hydroxide of M is a white powder which is insoluble in water. Examiner’s
Describe how you could show that this hydroxide is amphoteric. Use
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
[Total: 6]
3 A small piece of marble, CaCO3, was added to 5.0 cm3 of hydrochloric acid, concentration
1.0 mol / dm3, at 25 °C. The time taken for the reaction to stop was measured. The experiment
was repeated using 5.0 cm3 of different solutions of acids. The acid was in excess in all of the
experiments.
Typical results are given in the table.
experiment temperature / °C acid solution time / min

1 25 hydrochloric acid 1.0 mol / dm3 3
3 25 ethanoic acid 1.0 mol / dm3 10
(a) (i) Explain why it is important that the pieces of marble are the same size and the same
shape.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(ii) How would you know when the reaction had stopped?
.............................................................................................................................. [1]
(b) The equation for the reaction in experiment 1 is:
CaCO3(s) + 2HCl (aq) → CaCl 2(aq) + CO2(g) + H2O(l)
Complete the following ionic equation.
CaCO3(s) + 2H+(aq) → ............ + ............ + ............

[1]

4
For
(c) (i) Explain why the reaction in experiment 1 is faster than the reaction in experiment 2. Examiner’s
Use
....................................................................................................................................
.............................................................................................................................. [1]
(ii) The acids used for experiment 1 and experiment 3 have the same concentration.
Explain why experiment 3 is slower than experiment 1.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(iii) Explain in terms of collisions between reacting particles why experiment 4 is slower
than experiment 1.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]
[Total: 10]
4 The structural formula of cyclohexane is drawn below.
CH2
H 2C CH2
H 2C CH2
CH2
(a) The name gives information about the structure of the compound.
Hex because there are six carbon atoms and cyclo because they are joined in a ring.
What information about the structure of this compound is given by the ending ane?
...........................................................................................................................................
..................................................................................................................................... [2]
(b) What are the molecular and empirical formulae of cyclohexane?
molecular formula .............................
empirical formula .............................. [2]
© UCLES 2013 0620/31/M/J/13

5
For
(c) Draw the structural formula of cyclobutane. Examiner’s
Use
[1]
(d) (i) Deduce the molecular formula of hexene.
.............................................................................................................................. [1]
(ii) Explain why cyclohexane and the alkene, hexene, are isomers.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(e) Describe a test which would distinguish between cyclohexane and the unsaturated
hydrocarbon hexene.
test ....................................................................................................................................
result of test with cyclohexane ..........................................................................................
...........................................................................................................................................
result of test with hexene ..................................................................................................
..................................................................................................................................... [3]
[Total: 11]

6
For
5 The reactivity series shows the metals in order of reactivity. Examiner’s
Use
(a) The reactivity series can be established using displacement reactions. A piece of zinc is
added to aqueous lead nitrate. The zinc becomes coated with a black deposit of lead.
Zn + Pb2+ → Zn2+ + Pb
Zinc is more reactive than lead.
The reactivity series can be written as a list of ionic equations.
...... → ...... + ...... most reactive metal : the best reductant (reducing agent)
Zn → Zn2+ + 2e–
Fe → Fe2+ + 2e–
Pb → Pb2+ + 2e–
Cu → Cu2+ + 2e–
Ag → Ag+ + e–
(i) In the space at the top of the list, write an ionic equation for a metal which is more
reactive than zinc. [1]
(ii) Write an ionic equation for the reaction between aqueous silver(I) nitrate and zinc.
.............................................................................................................................. [2]
(iii) Explain why the positive ions are likely to be oxidants (oxidising agents).
.............................................................................................................................. [1]
(iv) Deduce which ion is the best oxidant (oxidising agent).
.............................................................................................................................. [1]
(v) Which ion(s) in the list can oxidise lead metal?
.............................................................................................................................. [1]
© UCLES 2013 0620/31/M/J/13

7
For
(b) A reactivity series can also be established by measuring the voltage of simple cells. The Examiner’s
diagram shows a simple cell. Use
voltmeter
V
cadmium copper
electrode electrode
sulfuric acid
Results from cells using the metals tin, cadmium, zinc and copper are given in the table
below.
electrode 1 electrode 2
cell voltage / volts
1 copper cadmium 0.74

2 copper tin 0.48
3 copper zinc 1.10
Write the four metals in order of increasing reactivity and explain how you used the data
in the table to determine this order.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
[Total: 9]
6 Ammonia is a compound which only contains the elements nitrogen and hydrogen. It is a
weak base.
(a) (i) Define the term base.
.............................................................................................................................. [1]
(ii) Given aqueous solutions of ammonia and sodium hydroxide, both having a
concentration of 0.1 mol / dm3, how could you show that ammonia is the weaker
base?
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]

8
For
(b) Ammonia is manufactured by the Haber Process. The economics of this process require Examiner’s
that as much ammonia as possible is made as quickly as possible. Use
Explain how this can be done using the following information.
The conditions for the following reversible reaction are:
● 450 °C
● 200 atmospheres pressure
● iron catalyst
N2(g) + 3H2(g) 2NH3(g) the reaction is exothermic
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [5]
(c) Another compound which contains only nitrogen and hydrogen is hydrazine, N2H4.
Complete the equation for the preparation of hydrazine from ammonia.
.....NH3 + NaCl O → N2H4 + ............ + H2O [2]
(d) The structural formula of hydrazine is given below.
H H
N N
H H
Draw a diagram showing the arrangement of the valency electrons in one molecule of
the covalent compound hydrazine.
Use x to represent an electron from a nitrogen atom.
Use o to represent an electron from a hydrogen atom.
[3]
© UCLES 2013 0620/31/M/J/13

9
For
(e) Hydrazine is a weak base and it removes dissolved oxygen from water. It is added to Examiner’s
water in steel boilers to prevent rusting. Use
(i) One way it reduces the rate of rusting is by changing the pH of water.
What effect would hydrazine have on the pH of water?
.............................................................................................................................. [1]
(ii) Give a reason, other than pH, why hydrazine reduces the rate of rusting.
.............................................................................................................................. [1]
[Total: 15]
7 The hydroxides of the Group I metals are soluble in water. Most other metal hydroxides are
insoluble in water.
(a) (i) Crystals of lithium chloride can be prepared from lithium hydroxide by titration.
burette filled with

hydrochloric acid of
concentration 2.20 mol / dm3
conical flask
25.0 cm3 of aqueous lithium hydroxide

and indicator
25.0 cm3 of aqueous lithium hydroxide is pipetted into the conical flask.
A few drops of an indicator are added. Dilute hydrochloric acid is added slowly to the
alkali until the indicator just changes colour. The volume of acid needed to neutralise
the lithium hydroxide is noted.
A neutral solution of lithium chloride, which still contains the indicator, is left. Describe
how you could obtain a neutral solution of lithium chloride which does not contain an
indicator.
....................................................................................................................................
.............................................................................................................................. [2]

10
For
(ii) You cannot prepare a neutral solution of magnesium chloride by the same method. Examiner’s
Describe how you could prepare a neutral solution of magnesium chloride. Use
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]
(b) The concentration of the hydrochloric acid was 2.20 mol / dm3. The volume of acid needed
to neutralise the 25.0 cm3 of lithium hydroxide was 20.0 cm3. Calculate the concentration
of the aqueous lithium hydroxide.
LiOH + HCl → LiCl + H2O
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(c) Lithium chloride forms three hydrates. They are LiCl.H2O, LiCl.2H2O and LiCl.3H2O.
Which one of these three hydrates contains 45.9 % of water?
Show how you arrived at your answer.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
[Total: 10]
8 There are three types of giant structure - ionic, metallic and giant covalent.
(a) In an ionic compound, the ions are held in a lattice by strong forces.
(i) Explain the term lattice.
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Explain how the ions are held together by strong forces.
....................................................................................................................................
.............................................................................................................................. [1]
© UCLES 2013 0620/31/M/J/13

11
For
(b) Describe the bonding in a typical metal. Examiner’s
Use
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(c) The electrical conductivities of the three types of giant structure are given in the following
table.
type of structure conductivity of solid conductivity of liquid
ionic poor good

metallic good good
giant covalent poor poor
Explain the differences in electrical conductivity between the three types of giant structure
and the difference, if any, between the solid and liquid states of the same structure.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [5]
[Total: 11]

© UCLES 2013
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
12
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/31/M/J/13
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY
1 (a) (i) contains carbon and hydrogen [1]

cond: only / just [1]
(ii) (different) boiling points [1]

cond: separate [1]
(b) bitumen-making roads / roofs / water-proofing, etc. [1]
lubricating fraction – waxes / vaseline / grease, etc. or machinery example, e.g. (oil a) bike /
hinges / reducing friction [1]
paraffin fraction – jet fuel / (home) heating or tractors or cooking or lighting [1]
gasoline fraction – petrol or fuel for cars / vans / trucks [1]
[Total: 8]
2 (a) 3 or III [1]
(b) good conductor and it is a metal/has delocalised (free) electrons [1]
(c) N or P or As or Sb [1]
accept Bi
(d) M2(SO4)3 [1]

accept: Ga2(SO4)3
(e) it would react with/dissolves in a named strong acid [1]

it would react with/dissolves in a named alkali [1]
it shows both basic and acid properties =1 [1]
it reacts with both acids and bases/alkalis =1 [1]
[max 2]
[Total: 6]

3 (a) (i) pieces have (same) surface area [1]

same amount / mass / quantity / volume / number of moles of carbonate [1]
(ii) no more bubbles / carbon dioxide or piece disappears / dissolves [1]
(b) experiment 1 Ca2+ + CO2 + H2O [1]
(c) (i) more concentrated or higher concentration (of acid) (in experiment 1) [1]
accept: arguments based on collision theory
(ii) ethanoic acid is a weak acid or hydrochloric acid is a strong acid [1]
accept: stronger or weaker
ethanoic acid less ionised / dissociated / lower / smaller concentration of hydrogen ions [1]
accept: less hydrogen ions and vice versa argument but not dissociation of ions
(iii) lower temperature (particles) have less energy [1]

moving more slowly [1]
fewer collisions / lower collision rate [1]
or
lower temperature (particles) have less energy [1]
fewer particles collide [1]
with the necessary energy to react [1]
note: less energy fewer successful collisions gains all 3 marks
[Total: 10]
4 (a) it is an alkane or hydrocarbon [1]

it is saturated or only C—C single bonds [1]
accept: no double bonds
(b) molecular formula C6H12 [1]

empirical formula CH2 [1]
(c) correct structural formula of cyclobutane [1]

(d) (i) C6H12 [1]

accept: a correct structural formula
(ii) same molecular formula not: chemical formula [1]

different structural formulae / structures [1]
(e) add bromine (water) or (l) [1]
cond: (remains) brown or orange or red or yellow [1]
cond: changes from brown, etc. to colourless or decolourises [1]

not: clear
OR
potassium manganate(VII) [1]
note: oxidation state not essential but if given must be correct or [0]
accept: potassium permanganate
cond: remains pink / purple [1]
cond: changes from pink to colourless (acidic) [1]

not: clear
cond: change from pink to green / brown (alkaline)
[Total: 11]
5 (a) (i) any metal above zinc

Mg → Mg2+ + 2e– [1]
(ii) Zn + 2Ag+ → Zn2+ + 2Ag [2]

Note: not balanced only [1]
(iii) because they can accept or gain electrons / change into atoms or can be reduced [1]
(iv) Ag+ or silver [1]

charge not essential but if given must be correct
(v) Ag+ and Cu2+ or silver and copper [1]

charge not essential but if given must be correct

(b) Cu Sn Cd Zn (i.e. all 4 in correct order) [1]

relates order to voltage [1]
one relevant comment from: [1]
higher reactivity metals are the negative electrode / copper is least reactive because it is the
positive electrode because copper would have the lowest voltage / copper cell V = 0 / the
bigger the difference in reactivity, the bigger the voltage / zinc has highest voltage because it
is most reactive / more reactive metals have higher voltage
[Total: 9]
6 (a) (i) proton or H+ acceptor [1]
(ii) (measure) pH or (use) UI indicator [1]

note: can be implied need not be explicit
sodium hydroxide has higher pH / ammonia(aq) has lower pH [1]
(this sentence would score 2 marks)
or
appropriate colours with UI / appropriate numerical values [1]
ammonia is closer to green, blue-green, turquoise or lighter blue
sodium hydroxide is darker blue / purple / violet [1]
or
measure electrical conductivity [1]
can be implied need not be explicit
ammonia (aq) is the poorer conductor/ sodium hydroxide is the better conductor [1]

(b) any five from:
• high pressure favours lower volume side / movement to right / ammonia side, or high
pressure increases the yield
• high pressure increases rate
• low temperature favours exothermic reaction / increases yield / favours the forward
reaction
• low temperature gives low rate or vice versa
• catalyst increases rate or lowers activation energy
• 450 °C low enough to give an economic yield but with catalyst gives a fast enough rate
note need whole concept to get this compromise temperature point [5]
(c) 2NH3 + NaClO → N2H4 + NaCl + H2O [2]

not balanced only 1
(d) 4 hydrogen atoms 1 bonding pair each [1]

2 nitrogen atoms with 1 bonding pair between them [1]
one non-bonding pair on each N (need not be seen as a pair) [1]
(e) (i) pH increases [1]
(ii) oxygen needed for rusting / removes oxygen / reacts with oxygen [1]
[Total: 15]
7 (a) (i) add carbon / animal charcoal [1]

filter [1]
OR
repeat experiment without indicator [1]

using same quantity / volume of acid [1]
(ii) add magnesium metal / carbonate / oxide / hydroxide

to (hot) (hydrochloric) acid [1]
cond: until in excess or no more dissolves or reacts [1]
cond: filter (to remove unreacted solid) [1]

(b) number of moles of HCl = 0.020 x 2.20 = 0.044 [1]

number of moles of LiOH = 0.044
concentration of LiOH = 0.044/0.025 = 1.769 (mol / dm3) [1]
accept 1.75 to 1.77 need 2 dp
correct answer scores = 2
(c) (for LiCl.2H2O)

mass of one mole = 78.5 [1]
percentage water = 36 / 78.5 x 100 [1]
45.9 so is LiCl.2H2O [1]
only award the marks if you can follow the reasoning and it gives 45.9% of water
note: if correct option given mark this and ignore the rest of the response
allow: max 2 for applying a correct method to another hydrate, [1] for the method and [1] for
the correct value, working essential
[Total: 10]
8 (a) (i) regular arrangement / repeating pattern NOT structure [1]

cond: ions [1]
not molecules / atoms
(ii) attraction between opposite charges / electrostatic attraction [1]
(b) delocalised / mobile / free / sea of electrons [1]

positive ions / cations
not atoms / protons / nuclei [1]
attraction between these electrons and ions [1]
(c) giant covalent

no ions [1]
no delocalised / free / mobile / sea of electrons or all electrons [1]
ionic
in ionic solid ions cannot move [1]
liquid ionic compound ions can move [1]
metallic
(both solid and liquid) metals have delocalised (or alternative term) electrons [1]
[Total: 11]

CHEMISTRY 0620/51
*9802488661*
where relevant.
by e-mail: info@cie.org.uk,
by phone: +44 1223 553554,
by fax: +44 1223 553558,
IB13 06_0620_51CI/3RP
2
For Question 1
(b) one beaker, 250 cm3
(c) one polystyrene cup
[H] (d) 1 g, 2 g, 3 g and 5 g samples of anhydrous potassium carbonate, K2CO3, in four dry stoppered
tubes, labelled 1 g of solid C, 2 g of solid C, 3 g of solid C and 5 g of solid C
(e) 3.5 g of potassium hydrogen carbonate, KHCO3, in a dry stoppered tube, labelled solid D
[H] (f) 200 cm3 of aqueous hydrochloric acid of concentration 2 mol / dm3, labelled hydrochloric acid
(g) access to water and distilled water
(h) one stirring thermometer, 0 – 110 °C
(i) one spatula
© UCLES 2013 0620/51/CI/M/J/13

3
For Question 2
(a) a stoppered test-tube, containing about 10 cm3 of aqueous ethanoic acid of concentration
1 mol / dm3, labelled liquid A
(b) a stoppered test-tube, containing about 5 cm3 of ethanol, labelled liquid B
(c) distilled water
(d) splints
(e) one dry watch glass
(f) pH indicator papers and chart
(g) rack of test-tubes
(h) one 2 cm strip of magnesium ribbon
(i) one small marble chip
[H] (j) spatula measure of copper(II) oxide, labelled copper oxide
(k) a very dilute solution of aqueous potassium manganate(VII) made by dissolving one crystal
of potassium manganate(VII) in about 100 cm3 of distilled water. At this concentration the
solution should be pale pink.
[T] (l) aqueous potassium dichromate(VI) solution of concentration 0.01 mol / dm3
[H] (m) aqueous sulfuric acid of concentration 1 mol / dm3
(n) spatula
(o) one 10 cm3 measuring cylinder
(p) a Bunsen burner and matches
(q) one test-tube holder
(r) teat pipettes
© UCLES 2013 0620/51/CI/M/J/13

4
© UCLES 2013 0620/51/CI/M/J/13

5
© UCLES 2013 0620/51/CI/M/J/13

6
© UCLES 2013 0620/51/CI/M/J/13

7
JUNE 2013
penalised.
© UCLES 2013 0620/51/CI/M/J/13

8
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
© UCLES 2013 0620/51/CI/M/J/13

*8601854076*
CHEMISTRY 0620/51
1 hour 15 minutes

Total
IB13 06_0620_51/3RP
2
For
1 You are going to investigate what happens when two different solids, C and D, react with Examiner’s
excess dilute hydrochloric acid. Use
Instructions
You are going to carry out five experiments.
(a) Experiment 1
Use a measuring cylinder to pour 30 cm3 of dilute hydrochloric acid into the polystyrene
cup supported in the beaker provided. Measure the temperature of the dilute hydrochloric
acid and record it in the table below. Add 1 g of solid C to the dilute hydrochloric acid and
stir the mixture with the thermometer.
Measure the maximum temperature reached by the liquid mixture. Record your result in
the table.
(b) Experiment 2
Empty the polystyrene cup and rinse it with water.

Repeat Experiment 1 using 2 g of solid C.
Record your results in the table.
(c) Experiments 3 and 4
Repeat Experiment 2 using 3 g and then 5 g of solid C.

Complete the final column in the table.
initial maximum
mass of temperature
Experiment temperature temperature
solid C / g change / °C
of acid / °C reached / °C
[4]
© UCLES 2013 0620/51/M/J/13

3
For
(d) Experiment 5 Examiner’s
Use
Repeat Experiment 1 using all of the solid D provided. Measure the minimum temperature
reached by the liquid mixture. Record your results in the spaces below.
Initial temperature of dilute hydrochloric acid = .........................°C
Final temperature of liquid mixture = .........................°C
Temperature change = .........................°C [2]
(e) Plot the results for Experiments 1, 2, 3 and 4 on the grid and draw a straight line graph.
temperature
change / °C
0 1 2 3 4 5 6
mass of solid C added / g
[4]
(f) (i) From your graph, deduce the temperature change of the solution when 6 g of solid
C is added to 30 cm3 of dilute hydrochloric acid.
Show clearly on the grid how you worked out your answer.
............................................ °C [2]
(ii) From your graph, deduce the mass of solid C that would give a temperature rise of
9 °C when added to 30 cm3 of dilute hydrochloric acid.
....................................................................................................................................
.............................................................................................................................. [2]

4
For
(g) What type of chemical process occurs when solid D reacts with dilute hydrochloric acid? Examiner’s
Use
..................................................................................................................................... [1]
(h) Suggest the effect on the results if Experiment 3 was repeated using 60 cm3 of dilute
hydrochloric acid.
...........................................................................................................................................
..................................................................................................................................... [2]
(i) Predict the temperature of the solution in Experiment 4 after 1 hour. Explain your answer.
...........................................................................................................................................
..................................................................................................................................... [2]
(j) When carrying out the experiments, what would be one advantage and one disadvantage
of taking the temperature readings after exactly one minute?
advantage .........................................................................................................................
...........................................................................................................................................
disadvantage ....................................................................................................................
..................................................................................................................................... [2]
[Total: 21]
© UCLES 2013 0620/51/M/J/13

5
For
2 You are provided with two different liquids, A and B. Examiner’s
A is an aqueous solution and B is a pure liquid. Use
Carry out the following tests on A and B, recording all of your observations in the table.
tests observations
tests on liquid A
Divide liquid A into four equal portions in

separate test-tubes.
(a) Describe the colour and smell of liquid A. ................................................................ [1]
Using a teat pipette, add a few drops of

the liquid to Universal Indicator paper.
Describe the colour and state the pH. ................................................................ [2]
(b) To the second portion of liquid A, add a .......................................................................

piece of magnesium ribbon.
After two minutes, test the gas given off .......................................................................
with a splint.
................................................................ [3]
(c) To the third portion of liquid A, add a

marble chip. ................................................................ [2]
(d) To the fourth portion of liquid A, add a

spatula measure of copper oxide.
Heat the solution gently and leave to

settle. ................................................................ [1]

6
For
tests observations Examiner’s
Use
tests on liquid B
(e) (i) To about 1 cm3 of liquid B, add a

few drops of dilute sulfuric acid ......................................................................
followed by aqueous potassium
dichromate(VI). Heat the mixture to ................................................................ [2]
boiling.
(ii) Repeat (e)(i) using aqueous ......................................................................

potassium manganate(VII) instead
of potassium dichromate(VI). ................................................................ [2]
(f) Place a few drops of liquid B on a dry

watch glass. Touch the surface of the
liquid with a lighted splint. ................................................................ [2]
(g) Identify liquid A.
..................................................................................................................................... [2]
(h) What conclusions can you draw about liquid B?
..................................................................................................................................... [2]
[Total: 19]
© UCLES 2013 0620/51/M/J/13

7
BLANK PAGE
© UCLES 2013 0620/51/M/J/13

8
Test for anions

produced

aluminium (Al 3+)
Test for gases

© UCLES 2013 0620/51/M/J/13

0620 CHEMISTRY
1 (c) Table of results for Experiments 1–4
mass of solids correctly recorded (1)
initial and maximum temperature boxes correctly completed (1)
temperature differences correct (1)
temperature changes increasing (1) [4]
(d) results for Experiment 5
initial and final temperatures completed (1)
temperature change completed correctly and shown as negative (1) [2]
(e) appropriate scale on y-axis which uses at least half of the grid (1)
all points correctly plotted (2), –1 for any incorrect ignore: origin
best fit straight line graph drawn with a ruler (1) [4]
(f) (i) value from graph (1) extrapolation shown clearly (1) [2]
(ii) value from graph (1)

shown clearly (1) [2]
(g) endothermic (1) [1]
(h) lower temperature change (1)
greater volume/more acid (1) [2]

note: halved = 2 marks
(i) room temperature / initial temperature from table (1)
reaction finished / owtte (1) [2]
(j) advantage e.g. comparability of results/fair test (1)
ignore: reference to accuracy or reliability
disadvantage e.g. reaction not finished / temperature still changing (1) [2]

2 tests on liquid A
(a) colourless (1) not: clear

and
smells acidic/vinegar/sour/pungent/bitter/strong not: sweet [1]
red/orange/yellow (1) pH = 3–6 (1) [2]
(b) bubbles/fizzes/effervesces (1)
lighted splint (1)
pops (1) ignore: hydrogen [3]
(c) slow/few (1)

bubbles/effervescence/fizz (1) [2]
(d) blue/green colour (1) not: precipitate [1]
tests on liquid B
(e) (i) yellow/orange (1)

turns green (1)
not: blue [2]
(ii) pink/purple (1) turns colourless/decolourises (1)

not: clear [2]
(f) blue/yellow/orange (1)

flame/catches fire/lights (1) [2]
(g) ethanoic acid/vinegar (2) [2]
(h) organic (1) fuel (1) not: flammable
note: ethanol/alcohol = 2 [2]

*0139348906*
CHEMISTRY 0620/61
1 hour

IB13 06_0620_61/2RP
2
For
1 Electricity was passed through a solution of concentrated hydrochloric acid using the Examiner’s
apparatus shown. Use
hydrogen
concentrated
hydrochloric acid
+ –
(a) Complete the boxes to identify the parts of the apparatus labelled. [2]
(b) Describe the test for hydrogen.
test ....................................................................................................................................
result ........................................................................................................................... [2]
(c) Describe how a sample of the gas given off at the positive electrode could be collected
and its volume measured.
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(d) The experiment was repeated using a concentrated aqueous solution of sodium chloride
instead of hydrochloric acid.
(i) State the name of the solution formed.
.............................................................................................................................. [1]
(ii) Give a test to show the presence of this product.
.............................................................................................................................. [1]
[Total: 8]
© UCLES 2013 0620/61/M/J/13

3
For
2 A student found a recipe for making elderberry wine by fermentation. Examiner’s
Use
1 kg elderberries
0.5 kg sugar
10 g yeast granules
3 dm3 water
The student decided to make some elderberry wine using the apparatus below.
airlock
water
fermenting mixture
The student carried out the following method.
Step 1 The elderberries were crushed.
Step 2 The crushed elderberries and sugar were added to the water and the mixture was
boiled for ten minutes. The crushed elderberries were then separated from the
mixture.
Step 3 Yeast was added to the liquid when it had cooled to room temperature.
(a) Suggest the purpose of the airlock in the apparatus.
..................................................................................................................................... [1]
(b) What apparatus could be used in Step 1?
..................................................................................................................................... [1]
(c) Draw a labelled diagram of the apparatus used to separate the crushed elderberries from
the mixture in Step 2.
[2]
(d) Why was the yeast in Step 3 not added until the liquid was at room temperature?
..................................................................................................................................... [1]

4
For
(e) (i) State one observation during the fermentation. Examiner’s
Use
.............................................................................................................................. [1]
(ii) Suggest how the rate of the fermentation reaction could be measured.
....................................................................................................................................
.............................................................................................................................. [2]
(f) Name the method that could be used to separate ethanol from the fermented mixture.
..................................................................................................................................... [1]
[Total: 9]
© UCLES 2013 0620/61/M/J/13

5
For
3 A student investigated the reaction between two different solids, C and D, and excess dilute Examiner’s
hydrochloric acid. Use
Five experiments were carried out.
(a) Experiment 1
A measuring cylinder was used to pour 30 cm3 of dilute hydrochloric acid into a polystyrene
cup. The temperature of the dilute hydrochloric acid was measured. 1 g of solid C was
added to the dilute hydrochloric acid and the mixture stirred with a thermometer.
The maximum temperature reached by the liquid mixture was measured.
(b) Experiment 2
The polystyrene cup was emptied and rinsed with water.

Experiment 1 was repeated using 2 g of solid C.
(c) Experiments 3 and 4
Experiment 2 was repeated using 3 g and then 5 g of solid C.
Use the thermometer diagrams to record the results in the table below.
Complete the final column in the table.
mass of initial maximum temperature

thermometer thermometer
experiment solid C temperature temperature difference
diagram diagram
/g of acid / °C reached / °C / °C
30 30
1 25 25
20 20
30 35
2 25 30
20 25
30 35
3 25 30
20 25
30 35
4 25 30
20 25
[3]

6
For
(d) Experiment 5 Examiner’s
Use
Experiment 1 was repeated using solid D. Use the thermometer diagrams to record the
results in the spaces below.
25 20
20 15
15 10
initial temperature of acid final temperature of liquid mixture
initial temperature of dilute hydrochloric acid = ....................... °C
final temperature of liquid mixture = ........................................ °C
temperature change = ............................................................. °C [2]
(e) Plot the results for Experiments 1, 2, 3 and 4 on the grid and draw a straight line graph.
15
10
temperature
difference / °C
0
0 1 2 3 4 5 6
mass of solid C / g
[4]
© UCLES 2013 0620/61/M/J/13

7
For
(f) (i) From your graph, deduce the temperature of the solution when 6 g of solid C is Examiner’s
added to 30 cm3 of dilute hydrochloric acid. Use
............................... °C [2]
(ii) From your graph, deduce the mass of solid C that would give a temperature rise of
9 °C when added to 30 cm3 of dilute hydrochloric acid.
....................................................................................................................................
.............................................................................................................................. [2]
(g) What type of chemical process occurs when solid D reacts with dilute hydrochloric acid?
..................................................................................................................................... [1]
(h) Suggest the effect on the results if Experiment 3 was repeated using 60 cm3 of dilute
hydrochloric acid.
...........................................................................................................................................
..................................................................................................................................... [2]
(i) Predict the temperature of the solution in Experiment 4 after 1 hour. Explain your answer.
...........................................................................................................................................
..................................................................................................................................... [2]
(j) When carrying out the experiments, what would be one advantage and one disadvantage
of taking the temperature readings after exactly one minute?
advantage .........................................................................................................................
...........................................................................................................................................
disadvantage ....................................................................................................................
..................................................................................................................................... [2]
[Total: 20]

8
For
4 A mixture of two solids, E and F, was analysed. Examiner’s
Solid E was the water-soluble salt aluminium chloride, Al Cl 3, and solid F was an insoluble Use
salt.
The tests on the mixture and some of the observations are in the following table.
tests observations
Distilled water was added to the mixture in a

boiling tube.
The contents of the boiling tube were shaken
and filtered, keeping the filtrate and residue for
the following tests.
The filtrate was divided into five portions in

five test-tubes.
(a) The first portion was used to describe the

appearance of the filtrate. appearance ........................................ [1]
(b) Several drops of aqueous sodium

hydroxide were added to the second
portion of the solution. ...................................................................
Excess aqueous sodium hydroxide was
then added to the test-tube. ............................................................ [3]
(c) Aqueous ammonia was added to the third ...................................................................

portion, dropwise and then in excess.
............................................................ [2]
(d) To the fourth portion of the solution, dilute

nitric acid and aqueous silver nitrate were
added. ............................................................ [2]
(e) To the fifth portion of the solution, about

1 cm3 of dilute nitric acid and barium
nitrate solution were added. ............................................................ [1]
© UCLES 2013 0620/61/M/J/13

9
For
tests observations Examiner’s
Use
(f) (i) To a little of the residue, dilute rapid effervescence

hydrochloric acid was added.
The gas given off was tested. gas turned limewater milky
(ii) The residue was heated, gently then

strongly. solid changed colour from green to black
(g) What conclusions can you draw about solid F?
...........................................................................................................................................
..................................................................................................................................... [2]
[Total: 11]

10
For
5 Identical pieces of steel were placed in two different boiling liquids for 12 hours. Examiner’s
The graphs show how the mass of each piece of steel changed. Use
graph A graph B
steel in boiling acid solution steel in boiling alkali solution
200 0.20
150 0.15
mass loss / mg
mass loss / mg
100 0.10
50 0.05
0 0
0 2 4 6 8 10 12 0 2 4 6 8 10 12
time / hours time / hours
(a) Give one similarity in the change in mass of the steel in both liquids.
..................................................................................................................................... [1]
(b) Describe two ways in which the mass loss shown in graph A is different from that shown
in graph B.
1. .......................................................................................................................................
...........................................................................................................................................
2. .......................................................................................................................................
..................................................................................................................................... [3]
(c) State two different safety precautions that would need to be taken when carrying out this
investigation.
1. .......................................................................................................................................
2. ................................................................................................................................. [2]
[Total: 6]
© UCLES 2013 0620/61/M/J/13

11
For
6 Copper(II) oxide and carbon are both black solids. Copper(II) oxide reacts with dilute sulfuric Examiner’s
acid to form aqueous copper(II) sulfate. Carbon does not react with dilute sulfuric acid. Use
You are given a mixture of copper(II) oxide and carbon and access to dilute sulfuric acid.
Plan an experiment to investigate the percentage of copper(II) oxide in the mixture.
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
............................................................................................................................................ [6]
[Total: 6]

12
BLANK PAGE
© UCLES 2013 0620/61/M/J/13

0620 CHEMISTRY
1 (a) electrode(s) / anode / cathode(either) (1)

allow: electrodes labelled wrong way round not: carbon/platinum
bulb / lamp / light (1) [2]
(b) lighted splint (1) pops (1) glowing splint = 0 [2]
(c) graduated test-tube / measuring cylinder (1) not: gas syringe as will not work
filled with electrolyte / acid / water inverted over electrode / owtte (1) [2]
(d) (i) sodium hydroxide (1) [1]
(ii) universal indicator with pH>7 / litmus turns blue (1) [1]
note: mark not awarded if (d)(i) is incorrect
2 (a) to prevent air / oxygen / bacteria entering jar (1) [1]
(b) pestle and / or mortar (1) [1]
(c) diagram of funnel and filter paper (1) labelled (1) [2]
(d) yeast would not work at high temperatures / kills yeast / denatures enzymes / owtte (1) [1]
allow: kills enzyme
(e) (i) bubbles / froth (1) [1]

not: gas / CO2 given off / turns cloudy
(ii) (collect gas) and measure volume / count bubbles (1)
over certain time interval (1) [2]

allow: one mark for timing until bubbles / reaction stopped
(f) fractional distillation (1) [1]

3 (c) Table of results for Experiments 1–4
mass of solids correctly recorded (1) 1, 2, 3, 5 g
initial and maximum temperature boxes correctly completed (1)
initial 21, 23, 22, 24
maximum 23, 27, 28, 34
temperature differences correct (1) 2, 4, 6, 10 [3]
(d) results for Experiment 5
initial and final temperatures completed 21 and 13 (1)
temperature change completed correctly and shown as negative –8 (1) [2]
(e) all points correctly plotted 3–1 for any incorrect
straight line graph drawn with a ruler (1) [4]
(f) (i) value from graph 12 °C ± half small square (1)
extrapolation shown clearly (1) allow: ecf [2]
(ii) value from graph 4.5 g ± half small square (1)
indication shown clearly (1) allow: ecf [2]
(g) endothermic (1) [1]
(h) lower temperature change (1)
3 °C (1)
greater volume/more acid (1) any 2 for [2]
(i) room temperature or initial temperature from table 24 °C (1)
reaction finished / owtte (1) [2]
(j) advantage, e.g. comparability of results / fair test (1)

ignore: reference to reliability / accuracy
disadvantage, e.g. reaction not finished / temperature still changing / may not reach
maximum temperature (1) [2]

4 tests on filtrate
(a) colourless (1) [1]

ignore: clear, not: white
(b) white (1) precipitate (1)
soluble in excess / dissolves (1) [3]
(c) white precipitate (1)

Insoluble / does not dissolve (1) [2]
(d) white (1) precipitate (1) [2]
(e) no reaction / no change / no precipitate (1) [1]
(g) transition metal / copper (1) carbonate (1) [2]
5 (a) both lose mass (1) [1]

not: change mass
(b) mass loss increases constantly in graph A (1)
becomes constant in graph B (after about 7–9 hours) (1)
mass loss or change is greater in acid/less in alkali (1) [3]
(c) goggles / lab coat / tongs / fume cupboard / well ventilated area any two [2]
ignore: reference to hair
6 weigh mixture (1)
add excess (1) sulfuric acid (1)
heat / stir (1)
filter (1) wash (1) dry (1) the carbon / residue
reweigh(1) calculate percentage (1) max 6 [6]
will not work = 0

ignore: details of evaporation of copper sulfate solution
note: must have at least one weighing for 6 marks

CHEMISTRY 0620/11
Paper 1 Multiple Choice October/November 2013
45 Minutes
Soft clean eraser
*6047676049*

IB13 11_0620_11/2RP
2
1 An attempt was made to compress a gas and a solid using the apparatus shown.
piston
gas solid
Which substance would be compressed and what is the reason for this?
substance reason
A gas the gas particles are close together

B gas the gas particles are far apart
C solid the solid particles are close together
D solid the solid particles are far apart
2 A student measures the rate of two reactions.
In one reaction, there is a change in mass of the reactants during the reaction.
In the second reaction, there is a change in temperature during the reaction.
Which piece of apparatus would be essential in both experiments?
A balance
B clock
C pipette
D thermometer
© UCLES 2013 0620/11/O/N/13

3
3 Diagram 1 shows the paper chromatogram of substance X.
diagram 1
Diagram 2 shows the cooling curve for substance Y.
temperature / °C
147
0
0 time
diagram 2
Which statement about X and Y is correct?
A X is a mixture and Y is a pure substance.

B X is a pure substance and Y is a mixture.
C X and Y are mixtures.
D X and Y are pure substances.
© UCLES 2013 0620/11/O/N/13 [Turn over

4
4 Element X has 7 protons.
Element Y has 8 more protons than X.
Which statement about element Y is correct?
A Y has more electron shells than X.

B Y has more electrons in its outer shell than X.
C Y is in a different group of the Periodic Table from X.
D Y is in the same period of the Periodic Table as X
23
5 Which statements about a sodium atom, 11 Na, are correct?
1 The number of protons and neutrons is the same.

2 The number of protons and electrons is the same.
3 The number of outer electrons is one.
A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only
6 Rubidium is in Group I of the Periodic Table and bromine is in Group VII.
Rubidium reacts with bromine to form an ionic compound.
Which row shows the electron change taking place for rubidium and the correct formula of the
rubidium ion?
electron change formula of ion formed
A electron gained Rb+

B electron gained Rb–
C electron lost Rb+
D electron lost Rb–
7 The diagrams show the electron arrangements in the atoms of four elements.
Which element does not form a covalent bond?
A B C D
key
e ee ee ee
e electron
ee ee ee ee
e e e e nucleus
e
ee ee ee
© UCLES 2013 0620/11/O/N/13

5
8 A solid mixture contains an ionic salt, X, and a covalent organic compound, Y.
Two students suggest methods of separating the mixture as shown.
method 1
shake with
water
X+Y
method 2
shake with
ethanol
X+Y
Which methods of separation are likely to work?
1 2
A
B
C
D
9 The formulae of compounds W, X and Y are shown.
W CuSO4.5H2O
X MgSO4.7H2O
Y Cu(NO3)2.6H2O
A W contains twice as many hydrogen atoms as oxygen atoms.

B X contains the most oxygen atoms.
C Y contains the most hydrogen atoms.
D Y contains the same number of hydrogen and oxygen atoms.

6
10 Which relative molecular mass, Mr, is not correct for the molecule given?
molecule Mr
A ammonia, NH3 17
B carbon dioxide, CO2 44
C methane, CH4 16
D oxygen, O2 16
11 The diagram shows the circuit for electrolysing lead(II) bromide and sodium chloride to liberate
the metal.
container for container for

lead(II) bromide sodium chloride
In what form are these salts electrolysed for liberating the metal?
lead(II) bromide sodium chloride
A concentrated solution concentrated solution

B concentrated solution molten
C molten concentrated solution
D molten molten
© UCLES 2013 0620/11/O/N/13

7
12 The diagram shows the electrolysis of concentrated aqueous sodium chloride.
+ –
anode cathode
carbon
rods
concentrated
aqueous sodium
chloride and litmus
What is the colour of the litmus at each electrode after five minutes?
colour at anode colour at cathode
A blue red
B red blue
C red colourless
D colourless blue
13 When anhydrous copper(II) sulfate is added to water a solution is formed and heat is given out.
thermometer
anhydrous
copper(II) sulfate
water
Which row correctly shows the temperature change and the type of reaction taking place?
temperature change type of reaction
A decreases endothermic
B decreases exothermic
C increases endothermic
D increases exothermic

8
14 Which fuel does not produce carbon dioxide when it burns?
A coal
B hydrogen
C methane
D petrol
15 A student investigates the rate of reaction between zinc and an excess of sulfuric acid.
The graph shows the results of two experiments, X and Y.
X
volume of
hydrogen
0
0 time
Which change explains the difference between X and Y?
A A catalyst is added in Y.
B A lower temperature is used in Y.
C Larger pieces of zinc are used in Y.
D Less concentrated acid is used in Y.
16 Anhydrous copper(II) sulfate can be made by heating hydrated copper(II) sulfate.
CuSO4.5H2O → CuSO4 + 5H2O
What can be added to anhydrous copper(II) sulfate to turn it into hydrated copper(II) sulfate?
A concentrated sulfuric acid

B sodium hydroxide powder
C sulfur dioxide
D water
© UCLES 2013 0620/11/O/N/13

9
17 The reactions shown may occur in the air during a thunder storm.
N2 + O2 → 2NO
2NO + O2 → 2NO2
NO + O3 → NO2 + O2
Which row shows what happens to the reactant molecules in each of these reactions?
N2 NO O3
A oxidised oxidised oxidised

B oxidised oxidised reduced
C reduced reduced oxidised
D reduced reduced reduced
18 Which are properties of an acid?
1 reacts with ammonium sulfate to form ammonia

2 turns red litmus blue
1 2
A
B
C
D
19 Which of the following are properties of the oxides of non-metals?
property 1 property 2
A acidic covalent
B acidic ionic
C basic covalent
D basic ionic

10
20 Compound X is tested and the results are shown in the table.
test result
aqueous sodium hydroxide is gas given off which turns damp

added, then heated gently red litmus paper blue
dilute hydrochloric acid is added effervescence, gas given off

which turns limewater milky
Which ions are present in compound X?
A ammonium ions and carbonate ions

B ammonium ions and chloride ions
C calcium ions and carbonate ions
D calcium ions and chloride ions
21 Calcium, on the left of Period 4 of the Periodic Table, is more metallic than bromine on the right of
this period.
Why is this?
Calcium has
A fewer electrons.
B fewer protons.
C fewer full shells of electrons.
D fewer outer shell electrons.
22 The diagrams show the labels of four bottles.
Which label is not correct?
A B C D
Bromine Iodine Potassium Sodium

Br2 I2 K Na
Harmful liquid. Danger Danger Danger

Do not spill. Avoid breathing vapour Store under water. Store under oil.
from the solid.
© UCLES 2013 0620/11/O/N/13

11
23 An element has a melting point of 1084 °C and a density of 8.93 g / cm3. It’s oxide can be used as
a catalyst.
In which position in the Periodic Table is the element found?
A B C
24 The diagram shows a light bulb.
filament
argon
Why is argon used instead of air in the light bulb?
A Argon is a good conductor of electricity.

B Argon is more reactive than air.
C The filament glows more brightly.
D The filament does not react with the argon.
25 Some properties of four elements W, X, Y and Z are listed.
1 W melts at 1410 °C and forms an acidic oxide.

2 X has a high density and is easily drawn into wires.
3 Y acts as a catalyst and its oxide reacts with acids.
4 Z is a red-brown solid used to make alloys.
Which of the elements are metals?
A 1 and 3 B 2, 3 and 4 C 2 and 3 only D 2 and 4 only

12
26 M is a shiny silver metal. It has a melting point of 1455 °C. Many of its compounds are green.
What is metal M?
A aluminium
B copper
C mercury
D nickel
27 Reactions of three metals and their oxides are listed in the table.
reacts with metal oxide reacts

metal
cold water with carbon
W no no
X no yes
Y yes no
A W X Y
B X W Y
C X Y W
D Y W X
28 Equations P and Q represent two reactions which occur inside a blast furnace.
P Fe2O3 + 3CO → 2Fe + 3CO2
Q CaCO3 → CaO + CO2
Which type of reactions are P and Q?
P Q
A redox redox
B redox thermal decomposition
C thermal decomposition redox
D thermal decomposition thermal decomposition
© UCLES 2013 0620/11/O/N/13

13
29 Which row describes the uses of mild steel and stainless steel?
mild steel stainless steel
A car bodies, cutlery chemical plant, machinery

B car bodies, machinery chemical plant, cutlery
C chemical plant, cutlery car bodies, machinery
D chemical plant, machinery car bodies, cutlery
30 In which process is carbon dioxide not formed?
A burning of natural gas

B fermentation
C heating lime
D respiration
31 Farmers add calcium oxide (lime) and ammonium salts to their fields.
The compounds are not added at the same time because they react with each other.
Which gas is produced in this reaction?
A ammonia
B carbon dioxide
C hydrogen
D nitrogen
32 The diagrams show four uses of iron.
In which of these uses is the iron most likely to rust?
A B C D
iron bucket iron cored iron hinges painted

electroplated aluminium on a gate iron fence
with zinc electricity cables

14
33 Which air pollutant is not made when coal burns in a power station?
A carbon monoxide
B lead compounds
C nitrogen oxides
D sulfur dioxide
34 In many countries river water is used for the washing of clothes.
The same water is not considered to be safe for drinking.
Why is it not safe for drinking?
A because river water contains dissolved salts

B because river water may contain harmful bacteria
C because river water may contain small particles of sand
D because river water may contain soap from washing clothes
35 The diagram shows a kiln used to heat limestone.
limestone
waste gases
gas burners
air
product
What is the product and what waste gas is formed?
product waste gas
A lime, CaO carbon monoxide

B lime, CaO carbon dioxide
C slaked lime, Ca(OH)2 carbon monoxide
D slaked lime, Ca(OH)2 carbon dioxide
© UCLES 2013 0620/11/O/N/13

15
36 Three types of organic compound are alkanes, alkenes and alcohols.
Which structure does not belong to any of these three types of compound?
A B
H H H
H H H
H C C C H
C C C H
H H H
H H
C D
H H H H H
H C C C O H H C C C OH
H H O H H H
37 The diagram shows some properties of two organic compounds X and Y.
reacts used
with as a
bromine fuel
steam
X and a Y
catalyst
used
polymerises as a
solvent
What are X and Y?
X Y
A ethane ethanoic acid

B ethane ethanol
C ethene ethanoic acid
D ethene ethanol

16
38 Petroleum is a mixture of hydrocarbons which can be separated into fractions using fractional
distillation.
Which fraction is used as fuel in jet engines?
A bitumen
B gasoline
C kerosene
D naphtha
39 The diagram represents ethene.
H H
C C
H H
Which compound has chemical properties similar to those of ethene?
A B C D
H H H H H H H H H H
H C C H H C C C H H C C O H H C C C
H H H H H H H H H
© UCLES 2013 0620/11/O/N/13

17
40 A chemist carried out a cracking reaction on a hydrocarbon, X, and obtained two products, Y
and Z.
H H H H H H H
X H C C C C H + H C C C
H H H H H H
Y Z
The chemist then wrote the following statements in his notebook.
1 A molecule of X has 7 carbon atoms.

2 Y is unsaturated.
3 Z will decolourise bromine water.
A 3 only B 1 and 2 C 1 and 3 D 1, 2 and 3
© UCLES 2013 0620/11/O/N/13

18
BLANK PAGE
© UCLES 2013 0620/11/O/N/13

19
BLANK PAGE
© UCLES 2013 0620/11/O/N/13

© UCLES 2013
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
20
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/11/O/N/13
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
MARK SCHEME for the October/November 2013 series
0620 CHEMISTRY
Cambridge is publishing the mark schemes for the October/November 2013 series for most IGCSE,
GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level
components.
IGCSE – October/November 2013 0620 11
Question Question
Key Key
Number Number
1 B 21 D
2 B 22 C
3 A 23 A
4 A 24 D
5 D 25 B
6 C 26 D
7 A 27 B
8 A 28 B
9 D 29 B
10 D 30 C
11 D 31 A
12 D 32 C
13 D 33 B
14 B 34 B
15 A 35 B
16 D 36 C
17 B 37 D
18 D 38 C
19 A 39 D
20 A 40 C

*7249373810*
CHEMISTRY 0620/21
Paper 2 October/November 2013
1 hour 15 minutes

IB13 11_0620_21/3RP
2
For
1 (a) Choose from the list of elements below to answer the following questions. Examiner’s
Use
calcium
helium
iodine
nickel
nitrogen
sodium
sulfur
Each element can be used once, more than once or not at all.
Which element:
(i) is an element present in most fertilisers, .................................................... [1]
(ii) is in Group VI of the Periodic Table, ........................................................... [1]
(iii) is in Period 5 of the Periodic Table, ............................................................ [1]
(iv) has a single electron shell containing two electrons, .................................. [1]
(v) is a transition element, ................................................................................ [1]
(vi) forms ions with a single negative charge? .................................................. [1]
(b) What is the meaning of the term element ?
...........................................................................................................................................
..................................................................................................................................... [1]
(c) Many of the elements in the Periodic Table have metallic properties.
Describe three physical properties which are typical of most metals.
1. .......................................................................................................................................
2. .......................................................................................................................................
3. ................................................................................................................................. [3]
[Total: 10]
© UCLES 2013 0620/21/O/N/13

3
For
2 Hydrogen chloride is an acidic gas. Examiner’s
Use
(a) (i) Complete the dot and cross diagram to show the electronic structure of hydrogen
chloride.
Cl H
[2]
(ii) Is hydrogen chloride a covalent or an ionic compound?

.............................................................................................................................. [1]
(b) Hydrogen chloride reacts with water to form hydrochloric acid.

Which one of the following is the most likely pH of hydrochloric acid?
[1]
(c) Hydrochloric acid reacts with both metal oxides and carbonates.
(i) Complete the word equation for the reaction of hydrochloric acid with calcium
carbonate.
hydrochloric + calcium → ...................... + ...................... + ......................

acid carbonate
...................... ...................... [3]
(ii) Complete the symbol equation for the reaction of magnesium oxide with hydrochloric
acid. Name the salt which is formed.
MgO + ......HCl → MgCl 2 + H2O
name of salt ......................................................................................................... [2]

4
For
(d) A student reacted magnesium with hydrochloric acid to find out how concentration Examiner’s
affects the rate of reaction. The magnesium was in excess. He measured the volume of Use
hydrogen produced at various time intervals.
The graph shows his results.
50
40
volume of hydrogen / cm3
30
20
10
0
0 50 100 150 200 250 300 350
time / seconds
(i) At what time had the reaction just finished?
.............................................................................................................................. [1]
(ii) What volume of hydrogen gas is given off during the first 50 seconds of the reaction?
volume of hydrogen ........................... cm3 [1]
(iii) The student repeated the experiment.

State two factors, apart from the concentration of hydrochloric acid, that should be
kept constant when repeating the experiment.
1. ................................................................................................................................
2. .......................................................................................................................... [2]
[Total: 13]
© UCLES 2013 0620/21/O/N/13

5
For
3 Organic compounds can be put into groups called homologous series. Examiner’s
Use
(a) Complete the following sentences about organic compounds and homologous series.
carbon chlorine different elements functional
hydrocarbon hydrogen oxide similar sulfur
Organic compounds usually contain atoms of ........................... and ........................... .
Each homologous series contains compounds with ................................. chemical
properties due to the presence of the same ................................. group. [4]
(b) Ethanol belongs to the alcohol homologous series.
(i) Draw the structure of ethanol, showing all atoms and bonds.
[2]
(ii) State the name of the two compounds formed when ethanol burns in excess air.
.......................................................... and .......................................................... [2]

6
For
(c) Salicylic acid is used to make aspirin. Examiner’s
The structure of salicylic acid is shown below. Use
O O
C
H C O H
C C
C C
H C H
(i) On this structure, put a ring around the carboxylic acid functional group. [1]
(ii) How many carbon atoms are there in one molecule of salicylic acid?
.............................................................................................................................. [1]
(iii) When making drugs and medicines, it is important that the chemicals used are pure.
State one other area of everyday life where purity is important.
.............................................................................................................................. [1]
[Total: 11]
© UCLES 2013 0620/21/O/N/13

7
For
4 The structures of diamond and graphite are shown below. Examiner’s
Use
= carbon atom
diamond graphite
(a) Describe the similarities and differences between these structures.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(b) Graphite burns in excess air to form carbon dioxide.

Describe a test for carbon dioxide.
test ....................................................................................................................................
result ........................................................................................................................... [2]
(c) When graphite is burnt in a limited supply of air, carbon monoxide is formed.
State one adverse effect of carbon monoxide on health.
..................................................................................................................................... [1]
(d) In the blast furnace for the production of iron, carbon monoxide reduces iron(III) oxide.
Fe2O3 + 3CO → 2Fe + 3CO2
How does this equation show that carbon monoxide is acting as a reducing agent?
..................................................................................................................................... [1]
(e) Iron(III) oxide and coke (carbon) are raw materials used in the production of iron.
State the names of two other raw materials used in the blast furnace for the production
of iron.
1. .......................................................................................................................................
2. ................................................................................................................................. [2]
[Total: 10]

8
For
5 Many plants contain coloured pigments. Examiner’s
A student crushes some plant leaves in alcohol to extract the pigments. Use
She then separates the pigments using the apparatus shown below.
(a) Write the correct labels in the boxes in the diagram above. [2]
(b) Draw an X on the diagram above to show where a drop of the pigment solution is placed
at the start of the experiment. [1]
(c) After leaving the apparatus for half an hour, the pigments separated from each other.
State the name given to this method of separating pigments.
..................................................................................................................................... [1]
(d) Some plants can absorb nickel from the ground. The nickel can then be extracted from
the plants and purified by electrolysis.
power supply
rod of + – rod of
impure nickel pure nickel
electrolyte
(i) Which one of the following is the most suitable electrolyte for this electrolysis.
Tick one box.
aqueous copper(II) sulfate
aqueous nickel(II) sulfate
solid nickel(II) sulfate
water [1]
© UCLES 2013 0620/21/O/N/13

9
For
(ii) Which one of the following elements is most likely to be formed at the negative Examiner’s
electrode during this electrolysis? Use
chlorine nickel sulfur oxygen

[1]
(iii) The positive electrode is called the anode.

State the name of the negative electrode.
.............................................................................................................................. [1]
(e) Electroplating is used to put a thin layer of one metal on top of another by electrolysis.
Give two reasons for electroplating metals.
1. .......................................................................................................................................
2. ................................................................................................................................. [2]
(f) (i) Hydrated nickel(II) chloride is green in colour.

When hydrated nickel(II) chloride is heated gently, it changes colour from green to
white.
NiCl 2.6H2O(s) NiCl 2(s) + ....................

hydrated nickel(II) chloride [1]
(ii) What does the sign mean?
.............................................................................................................................. [1]
(iii) How can you obtain a sample of green nickel(II) chloride starting with white nickel(II)
chloride?
.............................................................................................................................. [1]
[Total: 12]

10
For
6 The diagram shows a kettle of boiling water. Examiner’s
Use
water droplets
water vapour
kettle
As the water vapour cools it turns back to water droplets.
(a) Describe this change of state in terms of the kinetic particle theory.
In your answer, include
● the difference in the closeness of the water molecules as the water vapour changes
to water,
● the difference in the motion of the water molecules as the water vapour changes to
water.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(b) Water is a common solvent in the laboratory.
(i) What is meant by the term solvent ?
.............................................................................................................................. [1]
(ii) State the name of the solvent whose formula is C2H5OH.
.............................................................................................................................. [1]
(c) When ammonium chloride dissolves in water the temperature of the solution falls.
State the name of the energy change which results in the temperature falling.
..................................................................................................................................... [1]
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11
For
(d) Which one of the following conducts electricity. Examiner’s
Tick one box. Use
aqueous ammonium chloride
solid ammonium chloride
ammonia gas
chlorine gas
[1]
(e) (i) Complete the symbol equation for the reaction of lithium with water to form lithium
hydroxide and hydrogen.
2Li + .....H2O → 2.......... + H2

[2]
(ii) When 14 g of lithium react with water, 4 g of hydrogen are formed.

Calculate the mass of hydrogen formed when 70 g of lithium react with water.
[1]
[Total: 11]

12
For
7 The table shows some properties of seven different substances. Examiner’s
Use
relative
density relative relative electrical
substance thermal
/ g per cm3 strength conductivity
conductivity
aluminium 2.7 15 42 200.0

ceramic 2.5 15 does not conduct 1.6
copper 8.9 20 63 385.0
iron 7.9 25 11 80.0
lead 11.4 15 5 38.0
poly(ethene) 0.9 1 does not conduct 0.3
steel 7.8 90 2 25.0
(a) Use the information in this table to answer the following questions.
(i) Which substance is the best conductor of heat?
.............................................................................................................................. [1]
(ii) Suggest why copper is preferred to iron for electrical wiring in houses.
.............................................................................................................................. [1]
(iii) What property of ceramic makes it a good electrical insulator?
.............................................................................................................................. [1]
(iv) Which pure metal in the table conducts electricity least well?
.............................................................................................................................. [1]
(v) Suggest why steel rather than iron is used in making machinery.
.............................................................................................................................. [1]
(vi) Which metal in the table is the most dense?
.............................................................................................................................. [1]
(b) A solution of a metal salt reacts with aqueous sodium hydroxide to form a white precipitate.
The white precipitate is soluble in excess aqueous sodium hydroxide.
(i) Which one of the following ions is most likely to be present in the salt?
calcium copper(II) iron(II) zinc

[1]
(ii) State the name of the white precipitate.
.............................................................................................................................. [1]
© UCLES 2013 0620/21/O/N/13

13
For
(c) Copper(II) chloride can be made by the action of hydrochloric acid on copper(II) oxide. Examiner’s
Put the statements, A, B, C and D, about this preparation in the correct order. Use
A Leave the saturated solution to crystallise.

B Filter the solution to remove excess copper(II) oxide.
C Add excess copper(II) oxide to hydrochloric acid and warm.
D Evaporate the filtrate to the crystallisation point.
..................................................................................................................................... [1]
(d) The structure of copper(II) chloride is shown below.
Cl – Cl – Cl – Cl –
Cu2+ Cu2+
Cu2+ Cu2+
Cu2+ Cu2+
Write the simplest formula for copper(II) chloride.
..................................................................................................................................... [1]
(e) Suggest the product formed at each electrode when molten copper(II) chloride is
electrolysed.
at the positive electrode ....................................................................................................
at the negative electrode ............................................................................................ [2]
(f) When copper(II) chloride is heated strongly, a gas is given off.

The gas is green in colour and bleaches litmus paper.
..................................................................................................................................... [1]
[Total: 13]

14
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© UCLES 2013 0620/21/O/N/13

15
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© UCLES 2013 0620/21/O/N/13

© UCLES 2013
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/21/O/N/13
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY
components.
1 (a) (i) nitrogen [1]
(ii) sulfur [1]
(iii) iodine [1]
(iv) helium [1]
(v) nickel [1]
(vi) iodine [1]
(b) substance containing only 1 type of atom / substance which cannot be broken down further
by chemical means [1]
(c) Any 3 of: [3]
conducts electricity / conducts heat / conducts

shiny / lustrous
ductile / can be drawn into wires
malleable / can be shaped
ALLOW: high boiling point / high melting point / solid at room temperature
ALLOW: rings when hit / sonorous
[Total: 10]
2 (a) (i) pair of bonding electrons [1]

8 electrons around chlorine and no additional electrons around hydrogen [1]
(ii) covalent because has shared (pair of) electrons [1]

ALLOW: low melting point / low boiling point / it is a gas / doesn’t conduct electricity /
both non-metals
(b) pH 2 [1]
(c) (i) calcium chloride [1]

carbon dioxide [1]
water [1]
NOTE: do not allow formulae
(ii) 2 [1]
calcium chloride [1]

(d) (i) values from 215 to 245 (s) [1]
(ii) 22 (cm3) [1]
(iii) Any 2 of: [2]
temperature / mass of magnesium / particle size of magnesium / surface area of

magnesium
[Total: 13]
3 (a) 1 mark each correct answer [4]

carbon / hydrogen
hydrogen (if carbon given for first marking point) / carbon (if hydrogen given for first marking
point)
similar
functional
(b) (i)
H H
│ │
H–C– C–O–H [2]
│ │
H H
H H
│ │
H–C– C – OH (for 1 mark)
│ │
H H
(ii) carbon dioxide [1]

water [1]
(c) (i) COOH ringed [1]
(ii) 7 [1]
(iii) foodstuffs / drinks / cosmetics / water [1]

IGNORE: generalised answers e.g. kitchen / cleaning
[Total: 11]

4 (a) Any 4 of: [4]
both contain carbon atoms

both have covalent bonding
both are giant structures / lattices
both contain rings / have hexagonal patterns / rings of 6 atoms
in diamond, atoms arranged tetrahedrally
in graphite, atoms arranged in layers
flat rings in graphite
bent rings in diamond
all bonds same length in diamond
graphite has some longer bonds / weaker bonds
in diamond, each C atom joined to 4 others
in graphite, each C atom joined to 3 others
(b) lime water; [1]

turns milky / cloudy / white ppt [1]
2nd mark dependent on correct reagent
(c) poisonous / kills you / toxic [1]

ALLOW: harmful / higher level answers referring to combining with haem
IGNORE: causes respiration problems / damages lungs
(d) oxygen removed from iron oxide [1]

ALLOW: oxidation number of iron decreases / iron gains electrons / CO becomes oxidised /
oxygen adds to CO
(e) limestone [1]

air [1]
[Total: 10]
5 (a) filter paper / chromatography paper [1]

solvent / alcohol / other suitable solvent [1]
NOT: leaves / pigments in solvent
(b) X drawn on base line [1]
(c) chromatography [1]
(d) (i) 2nd box down ticked / aqueous nickel(II) sulfate [1]
(ii) nickel [1]
(iii) cathode [1]

(e) protection from corrosion / make it less reactive / make it unreactive [1]
better appearance / more shiny [1]
(f) (i) 6H2O [1]
(ii) reversible reaction / equilibrium reaction / reaction goes both ways /

reaction goes backwards as well (as forwards) [1]
IGNORE: reaction goes backwards / it is the reverse reaction
(iii) add water (to white nickel(II) chloride) / hydrate (white nickel(II) chloride) [1]
[Total: 12]
6 (a) Any 4 of: [4]
in steam, molecules are far apart

in water, molecules are close together
in steam, molecules are moving very fast
in water, molecules are moving slowly / sliding over each other
in steam more randomness in arrangement of molecules
NOTE: molecules are further apart in steam (than in water) = 2 marks
NOTE: molecules move faster in steam (than in water) = 2 marks
NOTE: for molecules the word particles can be used
NOT: implication of particles ‘apart’ in liquids
(b) (i) substance which dissolves another / it dissolves a solute / substance which dissolves a
solute / it dissolves something; [1]
(ii) ethanol [1]

IGNORE: alcohol
(c) endothermic [1]
(d) 1st box ticked /aqueous ammonium chloride [1]
(e) (i) LiOH on right [1]

2 on left (mark dependent on LiOH being correct) [1]
(ii) 20 g [1]
[Total: 11]
7 (a) (i) copper [1]
(ii) (copper is) better electrical conductor / iron is worse conductor [1]
IGNORE: copper is a good conductor

(iii) does not conduct (electricity) [1]
(iv) lead [1]
(v) stronger / has more strength [1]

IGNORE: tougher / harder / less malleable
(vi) lead [1]
(b) (i) zinc [1]
(ii) (zinc) hydroxide [1]

ALLOW: error carried forward from wrong metal in part (b)(i)
(c) C,B,D,A [1]
(d) CuCl2 [1]

ALLOW: Cl2Cu
(e) positive electrode: chlorine [1]

negative electrode: copper [1]
ALLOW: 1 mark for chlorine and copper reversed
(f) chlorine / Cl2 [1]
[Total: 13]


CHEMISTRY 0620/31
Paper 3 (Extended) October/November 2013
1 hour 15 minutes

IB13 11_0620_31/3RP R
2
For
1 For each of the following, name an element which matches the description. Examiner’s
Use
(a) It is used as a fuel in nuclear reactors.
..................................................................................................................................... [1]
(b) It is the only non-metal which is a good conductor of electricity.
..................................................................................................................................... [1]
(c) Inert electrodes are made from this metal.
..................................................................................................................................... [1]
(d) This gaseous element is used to fill balloons in preference to hydrogen.
..................................................................................................................................... [1]
(e) An element which can form an ion of the type X3–.
..................................................................................................................................... [1]
(f) It has the same electron distribution as the calcium ion, Ca2+.
..................................................................................................................................... [1]
(g) The element is in Period 5 and Group VI.
..................................................................................................................................... [1]
[Total: 7]
© UCLES 2013 0620/31/O/N/13

3
For
2 (a) Give three differences in physical properties between the Group I metal, potassium, and Examiner’s
the transition element, iron. Use
1. .......................................................................................................................................
2. .......................................................................................................................................
3. ................................................................................................................................. [3]
(b) The following metals are in order of reactivity.
potassium
zinc
copper
For those metals which react with water or steam, name the products of the reaction,
otherwise write ‘no reaction’.
potassium .........................................................................................................................
...........................................................................................................................................
zinc ...................................................................................................................................
...........................................................................................................................................
copper ...............................................................................................................................
..................................................................................................................................... [5]
[Total: 8]

4
For
3 Ammonia is manufactured by the Haber process. Examiner’s
Use
N2(g) + 3H2(g) 2NH3(g)
The forward reaction is exothermic.
(a) Describe how the reactants are obtained.
(i) Nitrogen
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Hydrogen
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [3]
(b) The percentage of ammonia in the equilibrium mixture varies with temperature and
pressure.
(i) Which pair of graphs, A, B or C, shows correctly how the percentage of ammonia at
equilibrium varies with temperature and pressure?
percentage percentage
pair A NH3 at NH3 at
equilibrium equilibrium
pair B NH3 at NH3 at
pair C NH3 at NH3 at
The pair with both graphs correct is ................................................................. [1]
© UCLES 2013 0620/31/O/N/13

5
For
(ii) Give a full explanation of why the pair of graphs you have chosen in (i) is correct. Examiner’s
Use
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [6]
(iii) Catalysts do not alter the position of equilibrium. Explain why a catalyst is used in
this process.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
[Total: 14]

6
For
4 20.0 g of small lumps of calcium carbonate and 40 cm3 of hydrochloric acid, concentration Examiner’s
2.0 mol / dm3, were placed in a flask on a top pan balance. The mass of the flask and contents Use
was recorded every minute.
cotton wool to prevent

drops of acid spray escaping
flask
40 cm3 of hydrochloric acid, 2.0 mol / dm3
20.0 g of small lumps of

calcium carbonate
balance
The mass of carbon dioxide given off was plotted against time.
mass of
carbon dioxide
0
0 time
CaCO3(s) + 2HCl (aq)  CaCl 2(aq) + H2O(l) + CO2(g)
In all the experiments mentioned in this question, the calcium carbonate was in excess.
(a) (i) Explain how you could determine the mass of carbon dioxide given off in the first five
minutes.
.............................................................................................................................. [1]
(ii) Label the graph F where the reaction rate is the fastest, S where it is slowing down
and 0 where the rate is zero. [2]
(iii) Explain how the shape of the graph shows where the rate is fastest, where it is
slowing down and where the rate is zero.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(b) Sketch on the same graph, the line which would have been obtained if 20.0 g of small
lumps of calcium carbonate and 80 cm3 of hydrochloric acid, concentration 1.0 mol / dm3,
had been used. [2]
© UCLES 2013 0620/31/O/N/13

7
For
(c) Explain in terms of collisions between reacting particles each of the following. Examiner’s
Use
(i) The reaction rate would be slower if 20.0 g of larger lumps of calcium carbonate and
40 cm3 of hydrochloric acid, concentration 2.0 mol / dm3, were used.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(ii) The reaction rate would be faster if the experiment was carried out at a higher
temperature.
....................................................................................................................................
....................................................................................................................................
.............................................................................................................................. [2]
(d) Calculate the maximum mass of carbon dioxide given off when 20.0 g of small lumps of
calcium carbonate react with 40 cm3 of hydrochloric acid, concentration 2.0 mol / dm3.
CaCO3(s) + 2HCl (aq)  CaCl 2(aq) + H2O(l) + CO2(g)
number of moles of HCl used =
mass of carbon dioxide = ................. g [4]
[Total: 15]

8
For
5 The alkenes are unsaturated hydrocarbons. They form a homologous series, the members of Examiner’s
which have the same chemical properties. Use
They undergo addition reactions and are easily oxidised.
(a) The following hydrocarbons are isomers.
CH3 CH CH CH2 CH3 CH2 CH2 CH CH2
CH3
(i) Explain why these two hydrocarbons are isomers.
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Give the structural formula of another hydrocarbon which is isomeric with the above.
[1]
(b) Give the structural formula and name of each of the products of the following addition
reactions.
(i) ethene and bromine
structural formula of product
name of product ................................................................................................... [2]
(ii) propene and hydrogen
name of product ................................................................................................... [2]
(iii) but-1-ene and water
name of product ................................................................................................... [2]
© UCLES 2013 0620/31/O/N/13

9
For
(c) Alkenes can be oxidised to carboxylic acids. Examiner’s
Use
(i) For example, propene, CH3 – CH = CH2, would produce ethanoic acid, CH3 – COOH,
and methanoic acid, H – COOH. Deduce the formulae of the alkenes which would
form the following carboxylic acids when oxidised.
ethanoic acid and propanoic acid
only ethanoic acid
[2]
(ii) Describe the colour change you would observe when an alkene is oxidised with
acidified potassium manganate(VII).
.............................................................................................................................. [2]
(d) Alkenes polymerise to form addition polymers.

Draw the structural formula of poly(cyanoethene), include at least two monomer units.
The structural formula of the monomer, cyanoethene, is given below.
H H
C C
H CN
[3]
[Total: 16]

10
For
6 Lead is an excellent roofing material. It is malleable and resistant to corrosion. Lead rapidly Examiner’s
becomes coated with basic lead carbonate which protects it from further corrosion. Use
(a) Lead has a typical metallic structure which is a lattice of lead ions surrounded by a ‘sea’
of mobile electrons. This structure is held together by attractive forces called a metallic
bond.
(i) Explain why there are attractive forces in a metallic structure.
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Explain why a metal, such as lead, is malleable.
....................................................................................................................................
.............................................................................................................................. [2]
(b) Basic lead(II) carbonate is heated in the apparatus shown below. Water and carbon
dioxide are produced.
basic lead
carbonate
heat
U-tube filled soda lime,

with silica gel carbon dioxide
to absorb water reacts here
(i) Silica gel absorbs water. Silica gel often contains anhydrous cobalt(II) chloride.
When this absorbs water it changes from blue to pink.
Suggest a reason.
.............................................................................................................................. [1]
(ii) Soda lime is a mixture of sodium hydroxide and calcium oxide. Why do these two
substances react with carbon dioxide?
....................................................................................................................................
.............................................................................................................................. [2]
(iii) Name two substances formed when soda lime reacts with carbon dioxide.
.............................................................................................................................. [2]
© UCLES 2013 0620/31/O/N/13

11
For
(c) Basic lead(II) carbonate has a formula of the type xPbCO3.yPb(OH)2 where x and y are Examiner’s
whole numbers. Use
Determine x and y from the following information.
PbCO3  PbO + CO2
Pb(OH)2  PbO + H2O
When heated, the basic lead(II) carbonate gave 2.112 g of carbon dioxide and 0.432 g of
water.
Mass of one mole of CO2 = 44 g

Mass of one mole of H2O = 18 g
Number of moles of CO2 formed = ..................... [1]
Number of moles of H2O formed = ..................... [1]
x = ..................... and y = .....................
Formula of basic lead(II) carbonate is ........................................................................ [1]
[Total: 12]

12
For
7 (a) The following are two examples of substitution reactions. Only the reaction involving Examiner’s
chlorine is a photochemical reaction. Use
CH4 + Cl 2  CH3Cl + HCl
CH4 + Br2  CH3Br + HBr
(i) Explain the phrase substitution reaction.
....................................................................................................................................
.............................................................................................................................. [1]
(ii) How do photochemical reactions differ from other reactions?
....................................................................................................................................
.............................................................................................................................. [1]
(b) Bond forming is exothermic, bond breaking is endothermic. Explain the difference
between an exothermic reaction and an endothermic reaction.
...........................................................................................................................................
..................................................................................................................................... [2]
© UCLES 2013 0620/31/O/N/13

13
For
(c) Use the bond energies to show that the following reaction is exothermic. Examiner’s
Bond energy is the amount of energy (kJ / mol) which must be supplied to break one mole Use
of the bond.
H H
H C H + Cl Cl → H C Cl + H Cl
H H
Bond energies in kJ / mol
Cl –Cl +242
C–Cl +338
C–H +412
H–Cl +431
bonds broken energy in kJ / mol
...................... .............................
...................... .............................
total energy = .............................
bonds formed energy in kJ / mol
...................... .............................
...................... .............................
total energy = .............................
...........................................................................................................................................
..................................................................................................................................... [4]
[Total: 8]

14
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© UCLES 2013 0620/31/O/N/13

15
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© UCLES 2013 0620/31/O/N/13

© UCLES 2013
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/31/O/N/13
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY
components.
1 (a) uranium / plutonium / thorium [1]
(b) graphite / carbon [1]
(c) platinum / titanium / mercury / gold [1]

NOT: carbon / graphite
(d) helium [1]
(e) nitrogen / phosphorus [1]
(f) argon [1]

ACCEPT: any ion 2 + 8 + 8 e.g. K+ etc.
(g) tellurium [1]

ACCEPT: correct symbol
[Total: 7]
2 (a) Any three of:

iron is harder
iron has higher density
ACCEPT: heavier or potassium lighter
iron has higher mp or bp
iron has higher tensile strength or stronger
iron has magnetic properties [3]
NOTE: has to be comparison, e.g. iron is hard (0) but iron is harder (1)
NOT: appearance e.g. shiny
ACCEPT: comparative statements relating to potassium
(b) potassium hydrogen (1) and potassium hydroxide (1)

zinc hydrogen (1) and zinc oxide (1)
copper no reaction (1) [5]
[Total: 8]

3 (a) (i) fractional distillation [1]

(liquid) air [1]
(ii) cracking / heat in presence of catalyst [1]

of alkane / petroleum [1]
to give an alkene and hydrogen [1]
OR: electrolysis (1)

named electrolyte (1)
hydrogen at cathode (1)
OR: from methane (1)

react water / steam (1)
heat catalyst (1)
only ACCEPT: water with methane or electrolysis
(b) (i) the pair with both graphs correct is C [1]

NOTE: mark (b)(ii) independent of (b)(i)
(ii) high pressure favours side with lower volume / fewer moles [1]
this is RHS / product / ammonia [1]
%NH3 / yield increases as pressure increases [1]
the forward reaction is exothermic [1]

exothermic reactions favoured by low temperatures [1]
%NH3 / yield decreases as temperature increases [1]
ACCEPT: reverse arguments
(iii) increases reaction rate [1]

ACCEPT: reduces activation energy [1]
OR: decreases the amount of energy particles need to react
OR: economic rate at lower temperature so higher yield
[Total: 14]
4 (a) (i) (mass at t =0) – (mass at t = 5) [1]

NOTE: must have mass at t = 5 not final mass
(ii) fastest at origin

slowing down between origin and flat section gradient = 0
where gradrient = 0
three of above in approximately the correct positions [2]
(iii) 3 correct comments about gradient = [2]

2 correct comments about gradient = [1]
1 correct comment about gradient = [0] [2]
(b) start at origin and smaller gradient [1]

same final mass just approximate rather than exact [1]

(c) (i) smaller surface area [1]

lower collision rate [1]
(ii) molecules have more energy [1]

collide more frequently / more molecules have enough energy to react [1]
(d) number of moles of HCl in 40 cm3 of hydrochloric acid,

concentration 2.0 mol / dm3 = 0.04 × 2.0 = 0.08 [1]
maximum number of moles of CO2 formed = 0.04 [1]
mass of one mole of CO2 = 44 g [1]
maximum mass of CO2 lost = 0.04 × 44 = 1.76 g [1]
[Total: 15]
5 (a) (i) have same molecular formula / both are C5H12 [1]
they have different structural formulae / different structures [1]
(ii) CH3-CH2-CH=CH-CH3 / any other correct isomer [1]
(b) (i) CH2-(Br)-CH2Br [1]

NOT: C2H4Br2
dibromoethane [1]
NOTE: numbers not required but if given must be 1, 2
(ii) CH3-CH2-CH3 [1]

NOT: C3H8
propane [1]
(iii) CH3-CH2-CH2-CH2-OH / CH3-CH2-CH(OH)-CH3 [1]

butanol [1]
numbers not required but if given must be correct and match formula
(c) (i) CH3-CH=CH-CH2-CH3 [1]

CH3-CH=CH-CH3 [1]
(ii) pink / purple [1]

colourless [1]
NOT: clear
(d) -CH2-CH(CN)-CH2-CH(CN)-
correct repeat unit CH2-CH(CN) [1]
COND: at least 2 units in diagram [1]
continuation [1]
[Total:16]

6 (a) (i) (attractive force between) positive ions [1]

and (negative) electrons [1]
opposite charges attract ONLY [1]
electrostatic attraction ONLY [1]
(ii) lattice / rows / layers of lead ions / cations / positive ions [1]
NOT: atoms / protons / nuclei
can slide past each other / the bonds are non-directional [1]
(b) (i) anhydrous cobalt chloride becomes hydrated [1]

ACCEPT: hydrous
(ii) carbon dioxide is acidic [1]

sodium hydroxide and calcium oxide are bases / alkalis [1]
(iii) Any two of:

water, calcium carbonate and sodium carbonate [2]
ACCEPT: sodium bicarbonate
(c) number of moles of CO2 formed = 2.112 / 44 = 0.048 [1]

number of moles of H2O formed = 0.432 / 18 = 0.024 [1]
x = 2 and y = 1 NOT: ecf from this line
formula is 2PbCO3.Pb(OH)2 / Pb(OH)2. 2PbCO3 [1]
[Total:12]
7 (a) (i) hydrogen (atoms) replaced by (atoms) of a different element e.g. chlorine [1]
NOT: substitute
(ii) light required [1]
(b) exothermic reaction gives out energy [1]

endothermic reaction absorbs
takes in energy [1]
(c) bonds broken energy

C-H +412
Cl-Cl +242
total energy +654 [1]
bonds formed energy

C-Cl –338
H-Cl –431
total energy –769 [1]
energy change –115 [1]
negative sign indicates exothermic [1]
[Total: 8]

CHEMISTRY 0620/51
Paper 5 Practical Test October/November 2013
*6033463552*
where relevant.
by phone: +44 1223 553554,
by fax: +44 1223 553558,
IB13 11_0620_51CI/2RP
2
For Question 1
(a) one 25 cm3 or 50 cm3 measuring cylinder
(b) one 50 cm3 burette
(c) one 250 cm3 conical flask
[H] (d) 100 cm3 of aqueous sodium hydroxide of concentration 0.2 mol / dm3 labelled sodium hydroxide
solution for question 1
(e) 100 cm3 of aqueous hydrochloric acid of concentration 0.2 mol / dm3 labelled acid K
(f) 0.3 g of powdered calcium carbonate labelled calcium carbonate
(h) phenolphthalein indicator
(i) white tile
(j) one funnel for filling burette
© UCLES 2013 0620/51/CI/O/N/13

3
For Question 2
(a) a stoppered test-tube containing about 10 cm3 of an aqueous solution of potassium iodide,
KI, of concentration 0.2 mol / dm3 labelled liquid L
(b) a stoppered test-tube containing about 3 cm3 of liquid paraffin (medicinal paraffin), labelled
liquid M
Do not use the paraffin used in heaters.
[N] [H] (c) a stoppered dry test-tube containing one small crystal of iodine, labelled iodine
The Supervisor should advise the candidates not to touch the crystal.
(d) rack of test-tubes
(e) cork or bung to fit test-tubes
(f) distilled water
(g) aqueous barium nitrate of concentration suitable to give a positive test for sulfate ions
(h) aqueous copper sulfate of concentration 0.1 mol / dm3
[F] [H] (i) 2 cm3 of ethanol, labelled ethanol
[N] [H] (j) aqueous silver nitrate of concentration suitable to give a positive halide test
[C] (k) aqueous nitric acid of concentration 1.0 mol / dm3
[C] (l) aqueous sodium hydroxide of concentration 1.0 mol / dm3
[H] (m) 2 cm3 of 20 volume hydrogen peroxide solution, labelled hydrogen peroxide
(n) starch indicator solution, labelled starch solution
(o) one 10 cm3 measuring cylinder
(p) teat pipettes
(q) access to a clock or stopwatch
© UCLES 2013 0620/51/CI/O/N/13 [Turn over

4
© UCLES 2013 0620/51/CI/O/N/13

5

6
© UCLES 2013 0620/51/CI/O/N/13

7
NOVEMBER 2013
penalised.

8
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
© UCLES 2013 0620/51/CI/O/N/13

*1146292889*
CHEMISTRY 0620/51
1 hour 15 minutes

Total
IB13 11_0620_51/2RP
2
For
1 You are going to investigate what happens when aqueous sodium hydroxide reacts with acid K. Examiner’s
Use
Instructions
(a) Experiment 1
Use a measuring cylinder to pour 25 cm3 of acid K into a conical flask. Add five drops of
phenolphthalein to the flask.
Fill the burette with the aqueous sodium hydroxide to the 0.0 cm3 mark.
Slowly add the aqueous sodium hydroxide to acid K in the flask and shake the mixture.
Continue to add aqueous sodium hydroxide to the flask until the solution shows a
permanent colour change.
Measure and record the volume in the table. Complete the table.
Pour the solution away and rinse the conical flask.
burette reading
final volume / cm3

initial volume / cm3
difference / cm3
[3]
(b) Experiment 2
Use a measuring cylinder to pour 50 cm3 of acid K into a conical flask. Add the 0.3 g of
powdered calcium carbonate to the flask and shake the flask until no further reaction is
observed.
Add five drops of phenolphthalein to the mixture in the flask.
Fill the burette with aqueous sodium hydroxide and record the burette reading. Slowly add
aqueous sodium hydroxide from the burette to the flask and shake the mixture. Continue
to add aqueous sodium hydroxide to the flask until the solution shows a permanent
colour change.
Measure and record the volume in the table. Complete the table.
burette reading
final volume / cm3

difference / cm3
[3]
© UCLES 2013 0620/51/O/N/13

3
For
(c) What colour change was observed after the sodium hydroxide solution was added to the Examiner’s
flask? Use
from ............................................................ to ............................................................ [2]
(d) What type of chemical reaction occurs when acid K reacts with sodium hydroxide?
..................................................................................................................................... [1]
(e) If Experiment 1 was repeated using 50 cm3 of acid K, what volume of sodium hydroxide
would be required to change the colour of the indicator?
..................................................................................................................................... [2]
(f) (i) What is the effect of adding 0.3 g of powdered calcium carbonate to acid K?
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Use your answers from (b) and (e) to work out the difference in the volume of sodium
hydroxide added when 0.3 g of calcium carbonate is mixed with 50 cm3 of acid K in
Experiment 2.
....................................................................................................................................
.............................................................................................................................. [2]
(iii) Estimate the mass of calcium carbonate that would need to be added to 50 cm3 of
acid K to require 0.0 cm3 of sodium hydroxide.
[1]
(g) What would be the effect on the results if the solutions of acid K were warmed before
adding the sodium hydroxide? Give a reason for your answer.
effect on results ................................................................................................................
reason ......................................................................................................................... [2]

4
For
(h) Suggest the advantage, if any, of Examiner’s
Use
(i) using a pipette to measure the volume of acid K.
....................................................................................................................................
.............................................................................................................................. [2]
(ii) using a polystyrene cup instead of a flask.
....................................................................................................................................
.............................................................................................................................. [2]
[Total: 22]
© UCLES 2013 0620/51/O/N/13

5
For
2 You are provided with two liquids, L and M. Examiner’s
Carry out the following tests on L and M, recording all of your observations in the table. Use
tests observations
tests on liquid L
(a) Describe the appearance of liquid L. ................................................................ [1]
Divide liquid L into five equal portions in

(b) (i) Add the first portion of liquid L to

the test-tube containing the iodine
crystal. Stopper the test-tube and
shake the contents. ................................................................ [1]
Now add an equal volume of liquid M

to the test-tube, stopper and shake ......................................................................
the contents. Leave to stand for five
minutes and continue to part (c). ................................................................ [2]
(ii) After five minutes, remove most of

the top layer using a teat pipette and
add ethanol to the liquid which you
have removed. Stopper the test-tube ......................................................................
and shake the contents. Leave to
stand for five minutes. ................................................................ [2]
(c) To the second portion of liquid L, add a

few drops of dilute nitric acid and about
1 cm3 of barium nitrate solution. ................................................................ [1]
(d) To the third portion of liquid L, add a few

drops of dilute nitric acid and about 1 cm3
of silver nitrate solution. ................................................................ [2]
(e) To the fourth portion of liquid L, add about ......................................................................

1 cm3 of aqueous copper sulfate, shake
and leave to stand for five minutes. ................................................................ [2]
(f) To the fifth portion of liquid L, add about ......................................................................

2 cm3 of aqueous hydrogen peroxide.
Now add about 1 cm3 of starch solution. ................................................................ [3]

6
For
(g) Why does the colour of liquid L change in test (b)(i)? Examiner’s
Use
...........................................................................................................................................
..................................................................................................................................... [1]
(h) What conclusions can you draw about liquid M from test (b)(i)?
...........................................................................................................................................
..................................................................................................................................... [2]
(i) What conclusions can you draw about liquid L?
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [1]
[Total: 18]
© UCLES 2013 0620/51/O/N/13

7
BLANK PAGE
© UCLES 2013 0620/51/O/N/13

8
Test for anions

produced

aluminium (Al 3+)
Test for gases

© UCLES 2013 0620/51/O/N/13

0620 CHEMISTRY
Cambridge is publishing the mark schemes for the October / November 2013 series for most IGCSE,
components.
1 (a) table of results for Experiment 1

initial final and difference volume boxes completed correctly (1)
readings to 1 decimal place (1)
comparable to supervisors (1) ±2 cm [3]
(b) table of results for Experiment 2

initial and final boxes completed correctly (1)
difference box completed correctly (1)
comparable to supervisors (1) ±5 cm3 [3]
(c) colourless (1) pink / magenta (1) [2]
(d) neutralisation / acid-base (1) [1]
(e) 2× volume for Experiment 1 from table (1) cm3 (1) [2]
allow: 1 mark for double the volume
(f) (i) reacts with (1) neutralises the acid (1)

less sodium hydroxide needed (1) max [2]
(ii) volume in (e) – volume added in Experiment 2 (1) e.g. 50–17

correct value (2) e.g. 33 [2]
(iii) estimate based on (ii) answer to (ii) / 3 divided into 50 × 0.1 e.g. 0.5
allow: 1 mark for 0.45–0.6g [1]
(g) no effect (1)

reason – reaction not affected by temperature / volumes / concentrations the same (1) [2]
(h) (i) more accurate (1) than a measuring cylinder (1)

not: more accurate than a burette = 0 [2]
(ii) no effect / advantage (1)

not measuring temperature changes / no temperature difference (1) [2]
2
2 (a) colourless / pale yellow (liquid) [1]

not: clear
(b) (i) liquid turns yellow / red / brown (1) [1]

(two) layers (1) top layer pink / purple (1) [2]
(ii) two layers / oil bubble (1) yellow (1) [2]
(c) no reaction / change / precipitate (1) [1]
(e) brown / white (1) precipitate (1) [2]
(f) yellow (1) bubbles / fizz / effervescence (1)

starch turns blue / black (1) [3]
not: black precipitate
(g) iodine dissolves / soluble / diffuses / owtte (1) [1]

not: reacts
(h) organic / hydrocarbon (1) solvent (1)

oil / immiscible (1) max [2]
(i) iodide / not a sulfate (1) [1]

not: iodine
3
*8106479956*
CHEMISTRY 0620/61
Paper 6 Alternative to Practical October/November 2013
1 hour

IB13 11_0620_61/2RP
2
For
1 A student investigated the products formed when ethanol was burned using the apparatus Examiner’s
shown. Use
suction
pump
liquid F
(a) Complete the box to identify the piece of apparatus. [1]
(b) Why is a suction pump used?
..................................................................................................................................... [1]
(c) (i) Suggest the purpose and identity of liquid F.
identity .......................................................................................................................
purpose ................................................................................................................ [2]
(ii) Why is the end of the delivery tube below the surface of liquid F?
....................................................................................................................................
.............................................................................................................................. [1]
(d) Give one expected observation in the horizontal part of the delivery tube.
...........................................................................................................................................
..................................................................................................................................... [2]
[Total: 7]
© UCLES 2013 0620/61/O/N/13

3
For
2 Eight steel rods of the same size were placed in solutions of different pH for one week. Examiner’s
The percentage corrosion of the rods was measured and the results plotted on the grid below. Use
30
percentage corrosion of steel rod
20
10
0
0 1 2 3 4 5 6 7 8
pH of solution
(a) Draw a best fit straight line through the points. [1]
(b) Why were the steel rods the same size?
..................................................................................................................................... [1]
(c) State one other variable which should have been kept constant.
..................................................................................................................................... [1]
(d) State one conclusion that could be drawn from the results.
..................................................................................................................................... [1]
(e) Determine the percentage corrosion of a steel rod in a solution of pH 6.5.
..................................................................................................................................... [1]
[Total: 5]

4
For
3 A student investigated the reaction between aqueous sodium hydroxide and acid K. Examiner’s
Two experiments were carried out. Use
(a) Experiment 1
Using a measuring cylinder, 25 cm3 of acid K was poured into a conical flask.
Phenolphthalein indicator was added to the flask. A burette was filled with aqueous
sodium hydroxide to the 0.0 cm3 mark. Aqueous sodium hydroxide was added from the
burette to the flask and the mixture shaken until the solution showed a permanent colour
change.
The final volume was measured. Use the burette diagram to record the final volume in
the table and complete the table.
37
38
39
final volume
burette reading
final volume / cm3
difference / cm3
[2]
(b) Experiment 2
The solution was poured away and the conical flask rinsed.
Using a measuring cylinder, 50 cm3 of acid K was poured into the conical flask. 0.3 g of
powdered calcium carbonate was added to the flask and the flask shaken until no further
reaction was observed.
Phenolphthalein was added to the mixture in the flask.
A burette was filled with the same aqueous sodium hydroxide and the initial volume
measured. Aqueous sodium hydroxide was added from the burette to the flask and the
mixture shaken until the solution showed a permanent colour change.
Use the burette diagrams to record the initial and final volumes in the table and complete
the table.
9 28
10 29
11 30
initial volume final volume
burette reading
final volume / cm 3

difference / cm3
[2]
© UCLES 2013 0620/61/O/N/13
5
For
(c) What colour change was observed after the sodium hydroxide solution was added to the Examiner’s
flask? Use
from ............................................................ to ............................................................ [2]
(d) What type of chemical reaction occurred when acid K reacted with sodium hydroxide?
..................................................................................................................................... [1]
(e) If Experiment 1 were repeated using 50 cm3 of acid K, what volume of sodium hydroxide
would be required to change the colour of the indicator?
..................................................................................................................................... [2]
(f) (i) What were the effects of adding 0.3 g of powdered calcium carbonate to acid K?
....................................................................................................................................
.............................................................................................................................. [2]
(ii) Use your answer in (e) to work out the difference between the volume of sodium
hydroxide needed to completely react with 50 cm3 of acid K and the volume of
sodium hydroxide used in Experiment 2.
....................................................................................................................................
.............................................................................................................................. [2]
(iii) Estimate the mass of calcium carbonate that would be needed to be added to 50 cm3
of acid K to require 0.0 cm3 of sodium hydroxide.
.............................................................................................................................. [1]
(g) What would be the effect on the results if the solutions of acid K were warmed before
adding the sodium hydroxide? Give a reason for your answer.
effect on results ................................................................................................................
reason ......................................................................................................................... [2]

6
For
(h) Suggest the advantage, if any, of Examiner’s
Use
(i) using a pipette to measure the volume of acid K.
....................................................................................................................................
.............................................................................................................................. [2]
(ii) using a polystyrene cup instead of a flask.
....................................................................................................................................
.............................................................................................................................. [2]
[Total: 20]
© UCLES 2013 0620/61/O/N/13

7
For
4 Two liquids, L and M, were analysed. L was aqueous potassium iodide. M was a colourless Examiner’s
liquid. Use
The tests on the liquids and some of the observations are in the following table.
tests observations
tests on liquid L
(a) Appearance of liquid L. ............................................................ [1]
Liquid L was divided into three equal portions

in separate test-tubes.
(b) (i) An iodine crystal was added to the first

portion of liquid L. The test-tube was
stoppered and the contents shaken. liquid turned orange
(ii) An equal volume of liquid M was added

to the test-tube, the contents shaken two layers were formed,
and left to stand for five minutes. pink top layer and orange lower layer
(c) To the second portion of liquid L, dilute

nitric acid and barium nitrate solution were
added. ............................................................ [1]
(d) To the third portion of liquid L, dilute nitric

acid and silver nitrate solution were added. ............................................................ [2]
(e) Why does the colour of liquid L change in test (b)(i)?
...........................................................................................................................................
..................................................................................................................................... [1]
(f) What conclusions can you draw about liquid M from test (b)(ii)?
...........................................................................................................................................
..................................................................................................................................... [2]
[Total: 7]

8
For
5 Two experiments using catalysts were carried out. Catalysts R and S were used to break Examiner’s
down 50 cm3 of aqueous hydrogen peroxide at a temperature of 20 °C. The volume of oxygen Use
given off was measured using the apparatus shown.
gas syringe
aqueous
hydrogen peroxide
catalyst
The gas syringe diagrams show the volume of oxygen formed every 30 seconds in each
experiment.
(a) Use the syringe diagrams to complete the volumes in the table.
using catalyst R using catalyst S

time / s syringe diagram volume / cm3 syringe diagram volume / cm3
0 10 0 10
0
20 30 40 10 20 30
30
30 40 50 30 40 50
60
50 60 70 50 60 70
90
60 70 80 60 70 80
120
60 70 80 60 70 80
150
60 70 80 60 70 80
180
[4]
© UCLES 2013 0620/61/O/N/13

9
For
(b) Plot a graph to show each set of results. Clearly label the graphs R and S. Examiner’s
Use
80
70
60
50
volume of
oxygen / cm3
40
30
20
10
0
0 30 60 90 120 150 180
time / s
[6]
(c) Which result using catalyst R was inaccurate?
..................................................................................................................................... [1]
(d) Which is the better catalyst in this reaction? Explain your answer.
...........................................................................................................................................
..................................................................................................................................... [2]
(e) Sketch a line on the grid to show the graph you would expect if the reaction with catalyst
R was repeated at 50 °C. [2]
[Total: 15]

10
For
6 Examiner’s
Old documents Use
Some documents are stored in containers with packets of silica gel crystals. These crystals
absorb water from air that enters the container. Water could damage the documents.
Anhydrous cobalt(II) chloride is added to the silica gel. As the crystals absorb water they
change colour from blue to pink. Heating the silica gel in an oven removes the water from the
crystals so that the crystals can be reused.
Plan an experiment to find the mass of water absorbed by a packet of silica gel crystals.
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
............................................................................................................................................ [6]
[Total: 6]
© UCLES 2013 0620/61/O/N/13

11
BLANK PAGE
© UCLES 2013 0620/61/O/N/13

12
BLANK PAGE
© UCLES 2013 0620/61/O/N/13

0620 CHEMISTRY
components.
1 (a) funnel (1) [1]
(b) to move products through the apparatus / owtte e.g. let the gases go out (1) [1]
(c) (i) limewater (1)

to detect carbon dioxide (1) [2]
(ii) so gas bubbles through liquid (1) [1]
(d) condensation / drops (1) water (1) [2]

allow: black deposit (1) soot / carbon (1)
2 (a) straight line drawn with a ruler through all points missing point at pH 5 (1) [1]
(b) idea of fair test / comparability (1) [1]
(c) temperature (1) [1]
(d) the lower the pH the greater the % corrosion / or converse / pH 1 is most corrosive (1) [1]
(e) 2.5% (1) [1]

initial, final and difference volume boxes completed correctly (1)
0.0, 38.0 difference 38.0
readings to 1dp (1) [2]

initial and final boxes completed correctly (1) 10.0, 29.0
difference (1) [2]
(c) colourless (1) pink (1) [2]
(d) neutralisation / exothermic (1) [1]

(e) 2 × volume for Experiment 1 from table / 76 (1) cm3 (1) [2]
(f) (i) reacts with the acid / neutralised (1) less sodium hydroxide needed (1) [2]
(ii) volume in (e) – volume added in Experiment 2 (1) e.g. 76–19

correct value (2) e.g. 57 cm3 [2]
(iii) estimate based on (ii) answer to (ii) / 3 divided into 19 × 0.1 + 0.3 = 0.4 g [1]
(g) no effect (1)

reason – reaction not affected by temperature (1) [2]
(h) (i) more accurate (1) than a measuring cylinder (1) [2]
(ii) no effect / advantage (1) not measuring temperature changes (1) [2]
4 tests on liquid L
(a) colourless (liquid) [1]

allow: (pale) yellow
(c) no reaction / change (1) [1]
(e) iodine dissolves / owtte (1) [1]
(f) organic (1) solvent (1) liquids do not mix (1) max [2]

5 (a) volumes completed correctly (4), –1 each incorrect [4]
time / s catalyst R catalyst S
0 0 0
30 23 16
60 34 36
90 59 51
120 66 63
150 71 69
180 72 72
(b) points plotted correctly (3) smooth curves (2) labels (1) [6]
(c) result at 60s / volume 34 / third result (1) [1]
(d) R (1) rate faster (1) [2]
(e) sketch to left of R graph / steeper (1) to same level (1) [2]
6 mass of silica gel (1)

heat in oven > 100 ˚C (1)
for specified realistic time / until turns blue (1)
reweigh (1) record (1)
heat in oven again to check constant mass / indication of colour change (1)
calculation (1) max [6]

CHEMISTRY 0620/11
45 Minutes
Soft clean eraser
*4174905704*

The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
IB14 11_0620_11/2RP
2
1 Which statement is an example of diffusion?
A A kitchen towel soaks up some spilt milk.

B Ice cream melts in a warm room.
C Pollen from flowers is blown by the wind.
D The smell of cooking spreads through a house.
2 A mixture is separated using the apparatus shown.
mixture
funnel
filter paper
What is the mixture?
A aqueous copper chloride and copper

B aqueous copper chloride and sodium chloride
C ethane and methane
D ethanol and water
3 Ethanol is made by fermentation.
How is ethanol obtained from the fermentation mixture?
A chromatography
B crystallisation
C electrolysis
D fractional distillation
4 What is different for isotopes of the same element?
A nucleon number
C number of electrons in the outer shell
D proton number
© UCLES 2014 0620/11/O/N/14

3
5 Which element has the atomic structure shown?
e e
e e
key
e e e electron
e e n neutron
e 16n e
e e nucleus
e e
A Al B P C S D Si
6 Slate has a layered structure and can easily be split into thin sheets.
Which diagram shows a structure most like that of slate?
A B C D
7 Sodium chloride is an ionic solid.
Which statement is not correct?
A Ions are formed when atoms lose or gain electrons.

B Ions in sodium chloride are strongly held together.
C Ions with the same charge attract each other.
D Sodium chloride solution can conduct electricity.

4
8 Caesium chloride and rubidium bromide are halide compounds of Group I elements.
Caesium chloride has the formula ……1……, a relative formula mass ……2…… that of rubidium
bromide and bonds that are ……3…… .
1 2 3
A CaCl different from ionic

B CaCl the same as covalent
C CsCl different from ionic
D CsCl the same as covalent
9 How many atoms of hydrogen are there in a molecule of ethanol, C2H5OH?
A 1 B 2 C 5 D 6
10 Iron forms an oxide with the formula Fe2O3.
What is the relative formula mass of this compound?
A 76 B 100 C 136 D 160
11 Which metal could not be used for electroplating by using an aqueous solution?
A chromium
B copper
C silver
D sodium
12 Which products are formed at the electrodes when a concentrated solution of sodium chloride is
electrolysed?
cathode (–) anode (+)
A hydrogen chlorine
B hydrogen oxygen
C sodium chlorine
D sodium oxygen
© UCLES 2014 0620/11/O/N/14

5
13 Which statements about exothermic and endothermic reactions are correct?
1 During an exothermic reaction, heat is given out.

2 The temperature of an endothermic reaction goes up because heat is taken in.
3 Burning methane in the air is an exothermic reaction.
14 A power station was designed to burn gaseous fuels only.
Which two substances could be used?
A carbon dioxide and hydrogen

B carbon dioxide and 235U
C hydrogen and methane
D methane and 235U
15 The rate of a reaction depends on temperature, concentration, particle size and catalysts.
A Catalysts can be used to increase the rate of reaction.

B Higher concentration decreases the rate of reaction.
C Higher temperature increases the rate of reaction.
D Larger particle size decreases the rate of reaction.
16 The diagram shows the change from an anhydrous salt to its hydrated form.
forward
anhydrous salt hydrated salt
reverse
A forward reaction requires heat and water

B forward reaction requires water only
C reverse reaction requires heat and water
D reverse reaction requires water only

6
17 The equations for two reactions P and Q are given.
P 2NaNO2 + O2 → 2NaNO3
Q 2HgO → 2Hg + O2
In which of these reactions does oxidation of the underlined substance occur?
P Q
A
B
C
D
18 Which changes decrease the rate of reaction between magnesium and air?
1 heating the magnesium to a higher temperature

2 using a higher proportion of oxygen in the air
3 using magnesium ribbon instead of powdered magnesium
A 1, 2 and 3 B 1 only C 2 only D 3 only
19 Which substance is the most acidic?
substance pH
A calcium hydroxide 12
B lemon juice 4
C milk 6
D washing up liquid 8
20 The positions of elements W, X, Y and Z in the Periodic Table are shown.
Y
X Z
Which elements form basic oxides?
A W, X and Y B W and X only C Y only D Z only
© UCLES 2014 0620/11/O/N/14

7
21 How many different salts could be made from a supply of dilute sulfuric acid, dilute hydrochloric
acid, copper, magnesium oxide and zinc carbonate?
A 3 B 4 C 5 D 6
22 The graph shows how the pH of soil in a field changes over time.
At which point was the soil neutral?
11 A
pH of 7 B
soil D
5 C
time
23 Elements in Group I of the Periodic Table react with water.
Which row describes the products made in the reaction and the trend in reactivity of the
elements?
products trend in reactivity
A metal hydroxide and hydrogen less reactive down the group

B metal hydroxide and hydrogen more reactive down the group
C metal oxide and hydrogen less reactive down the group
D metal oxide and hydrogen more reactive down the group

8
24 An element X has the two properties listed.
1 It acts as a catalyst.
2 It forms colourless ions.
Which of these properties suggest that X is a transition element?
property 1 property 2
A
B
C
D
25 An inert gas X is used to fill weather balloons.
Which descriptions of X are correct?
number of outer
structure of gas X
electrons in atoms of X
A 2 single atoms
B 2 diatomic molecules
C 8 single atoms
D 8 diatomic molecules
26 The table shows the reactions of four different metals with water.
metal reaction
W reacts vigorously with cold water

X no reaction with water
Y reacts very slowly with water, more vigorously with steam
Z reacts violently with cold water
What is the correct order of reactivity, from most reactive to least reactive?
A W→X→Y→Z
B W→Z→Y→X
C Z→W→X→Y
D Z→W→Y→X
© UCLES 2014 0620/11/O/N/14

9
27 Which information about an element can be used to predict its chemical properties?
A boiling point
B density
C melting point
D position in the Periodic Table
28 Aluminium is the most common metal in the Earth’s crust.
Which is not a property of aluminium?
A low density
B resistance to corrosion
C good conductor of electricity
D poor conductor of heat
29 The oxide of element X is reduced by heating with carbon.
Element X does not react with cold water, steam or dilute hydrochloric acid.
What is X?
A copper
B iron
C magnesium
D zinc
30 Which object is least likely to contain aluminium?
A a bicycle frame
B a hammer
C a saucepan
D an aeroplane body
31 Which reaction involves oxidation?
A heating hydrated copper(II) sulfate in the air

B polymerisation of ethene
C rusting of iron
D thermal decomposition of calcium carbonate

10
32 Which method can be used to obtain ammonia from ammonium sulfate?
A Heat it with an acid.

B Heat it with an alkali.
C Heat it with an oxidising agent.
D Heat it with a reducing agent.
33 Which method of purification would produce water most suitable for drinking?
A
filtration
B
chlorination
muddy purified
river water
water C
settlement filtration
D
filtration chlorination
34 Which statement about methane is not correct?
A It is a liquid produced by distilling petroleum.

B It is produced as vegetation decomposes.
C It is produced by animals, such as cows.
D It is used as a fuel.
35 Which is an air pollutant that affects a part of the body other than the lungs and blood system?
A lead compounds
B nitrogen
C oxides of nitrogen
D sulfur dioxide
© UCLES 2014 0620/11/O/N/14

11
36 Increasing the number of atoms in one molecule of a hydrocarbon increases the amount of
energy released when it burns.
What is the correct order?
less energy more energy

released released
A ethene ethane methane

B ethene methane ethane
C methane ethane ethene
D methane ethene ethane
37 Which molecular structure shows hexene?
A B
H H H H H H H H H H H
H C C C C C C H C C C C C C H
H H H H H H H H H H H H
C D
H H H H H H H H H H H O
H C C C C C C O H H C C C C C C
H H H H H H H H H H H O H
38 The diagram shows three repeat units in the structure of an addition polymer.
H Cl H H H Cl
C C C C C C
H H H Cl H H
Which alkene monomer is used to make this polymer?
A B C D
Cl Cl H Cl H H Cl H
H C C H H C C H C C C C
H H H H H Cl H Cl

12
39 Which statement about alkenes is not correct?
A The functional group is C=C.

B The structural difference between one member and the next is – CH3 –.
C They form a homologous series.
D They turn aqueous bromine from brown to colourless.
40 Ethanol can be manufactured from substance X.
catalyst
substance X + steam ethanol
A carbon dioxide
B ethene
C hydrogen
D oxygen
© UCLES 2014 0620/11/O/N/14

13
BLANK PAGE
© UCLES 2014 0620/11/O/N/14

14
BLANK PAGE
© UCLES 2014 0620/11/O/N/14

15
BLANK PAGE
© UCLES 2014 0620/11/O/N/14

© UCLES 2014
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/11/O/N/14
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY
Cambridge is publishing the mark schemes for the October/November 2014 series for
most Cambridge IGCSE®, Cambridge International A and AS Level components and some
Cambridge O Level components.
® IGCSE is the registered trademark of Cambridge International Examinations.

Cambridge IGCSE – October/November 2014 0620 11
Question Question
Key Key
Number Number
1 D 21 B
2 A 22 B
3 D 23 B
4 A 24 B
5 B 25 A
6 A 26 D
7 C 27 D
8 C 28 D
9 D 29 A
10 D 30 B
11 D 31 C
12 A 32 B
13 C 33 D
14 C 34 A
15 B 35 A
16 B 36 D
17 B 37 A
18 D 38 C
19 B 39 B
20 A 40 B

*4095387716*
CHEMISTRY 0620/21
1 hour 15 minutes
You may use an HB pencil for any diagrams or graphs.

IB14 11_0620_21/3RP
2
1 The structures of five carbon compounds are shown below.
A B C
H H H H H Br Br
H C C C H C C H C C H
H H H H H H H
D E
H H O
H C H H C C
H H O H
(a) Answer the following questions about these compounds. Each compound may be used once,
(i) Which compound, A, B, C, D or E, is ethanoic acid? ................................................... [1]
(ii) Which two compounds are saturated hydrocarbons? ..................... and ..................... [1]
(iii) Which compound is the main constituent of natural gas? ............................................ [1]
(iv) Which compound reacts with steam to form ethanol? .................................................. [1]
(v) Which compound is causing concern as a greenhouse gas? ...................................... [1]
(vi) Which two compounds are in the same homologous series? ................ and .............. [1]
(b) Deduce the molecular formula for compound C.
.............................................................................................................................................. [1]
(c) Complete the symbol equation for the complete combustion of compound A.
C3H8 + .....O2 → 3CO2 + .....H2O [2]
[Total: 9]
© UCLES 2014 0620/21/O/N/14

3
2 The diagram shows a bottle of mineral water. The concentration of the ions present in the water is
shown on the label. The pH of the water is also shown.
concentration
ions present in mg / 1000 cm3
poly(ethene) chloride, Cl – 0.71
bottle X, F –
0.31
magnesium, Mg2+ 0.02
2+
manganese, Mn 0.01
–
Y, NO3 0.70
+
potassium, K 0.44
sodium, Na+ 1.22
pH = 6.6
(a) (i) Which positively charged ion is present in the highest concentration?
....................................................................................................................................... [1]
(ii) State the name of:
ion X ...................................................................................................................................
ion Y ...................................................................................................................................
[2]
(iii) Calculate the mass, in mg, of sodium ions in 200 cm3 of mineral water.
..................... mg [1]
(iv) Which one of the following phrases best describes the pH of this mineral water?
Tick one box.
neutral
strongly acidic
strongly alkaline
weakly acidic
weakly alkaline
[1]
(b) Describe a test for chloride ions.
test .............................................................................................................................................
result ..........................................................................................................................................
[2]

4
(c) The mineral water bottle is made of poly(ethene).
Complete the following sentence about poly(ethene) using words from the list below.
atom ionic monomer polymer reactant saturated
Poly(ethene) is a ................................. made by the addition of ................................. units.

[2]
[Total: 9]
3 Rose oil contains 2-phenylethanol.

The structure of 2-phenylethanol is shown below.
H H
C C H H
H C C C C O H
C C H H
H H
(a) On the structure above, draw a ring around the alcohol functional group. [1]
(b) When heated with an alkali, 2-phenylethanol forms styrene.

Styrene is an unsaturated compound.
Describe a test for an unsaturated compound.
test .............................................................................................................................................
result ..........................................................................................................................................
[2]
(c) Rose petals contain a variety of different coloured pigments.

A student wants to identify these pigments.
(i) She grinds up rose petals with a solvent.

Explain why.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) She then filters the solution through some glass wool.
Suggest why she does not use filter paper.
....................................................................................................................................... [1]
© UCLES 2014 0620/21/O/N/14

5
(d) The student uses the apparatus shown below to identify the different pigments in the mixture.
glass cover
filter paper
pure solvent
(i) State the name of this method of separating the pigments.
....................................................................................................................................... [1]
(ii) On the diagram above, draw a spot, ●, to show where the mixture of pigments is placed at
the start of the experiment. [1]
(iii) What is the purpose of the glass cover?
....................................................................................................................................... [1]
(iv) The student also puts four spots of pure pigments, A, B, C and D, onto the filter paper.
The diagram below shows the results of her experiment.
pigments A B C D
from
rose petal
Which of the pigments, A, B, C and D, are present in the rose petals?
....................................................................................................................................... [1]

6
(e) The solvent used in the experiment is ethanol.

Draw the structure of a molecule of ethanol showing all atoms and bonds.
[2]
[Total: 12]
© UCLES 2014 0620/21/O/N/14

7
4 A student wants to compare the energy released when different fuels are burned.
He measures the increase in temperature of the water in a metal can when the fuels are burned.
clamp
water
metal can
glass spirit burner

fuel
top-pan balance
(a) What piece of apparatus is missing from the diagram above?
.............................................................................................................................................. [1]
(b) State two things the student should keep the same when burning each fuel.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(c) Suggest why the water in the can should be stirred.
....................................................................................................................................................
.............................................................................................................................................. [1]
(d) What happens to the reading on the top-pan balance as the fuel burns?
....................................................................................................................................................
.............................................................................................................................................. [2]

8
(e) The results of burning four fuels, D, E, F and G, are shown in the table below.
temperature of water at temperature of water at

fuel
start of experiment / °C end of experiment / °C
D 20 45
E 19 43
F 16 44
G 21 46
Which fuel produced the greatest temperature rise in the water?
.............................................................................................................................................. [1]
(f) The metal can is made of mild steel coated with tin.
(i) Steel is an alloy.

What is meant by the term alloy?
.............................................................................................................................................
....................................................................................................................................... [1]
(ii) Why does the tin prevent the steel can from rusting?
.............................................................................................................................................
....................................................................................................................................... [2]
(g) Glass is made from silicon(IV) oxide.

Part of the structure of silicon dioxide is shown below.
oxygen atom
silicon atom
Which one of the following best describes the structure of silicon dioxide?
Tick one box.
giant covalent
giant ionic
simple atomic
simple molecular
[1]
[Total: 11]
© UCLES 2014 0620/21/O/N/14

9
5 (a) Describe how acids react with metals and with metal oxides.
In your answer:
● refer to a particular metal and metal oxide,
● illustrate your answer with at least one word equation.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
(b) When metals react with hydrochloric acid, the temperature of the reaction mixture increases.
Which one of the following words best describes this reaction?
Draw a ring around the correct answer.
endothermic exothermic isotopic radioactive

[1]
(c) Uranium is a metal which has several radioactive isotopes. Some of these are used as sources
of energy.
State one other use of radioactive isotopes.
.............................................................................................................................................. [1]
(d) Complete the table below to show the number of protons, neutrons and electrons in two
isotopes of uranium.
235 238
isotope 92 U 92 U
protons
neutrons
electrons
[3]
[Total: 9]

10
6 The organic compound 1-bromobutane reacts with excess sodium hydroxide to form butan-1-ol.
A scientist studied the rate of this reaction by finding out how the concentration of sodium hydroxide
changed with time.
The graph below shows the results.
0.25
0.20
0.15
concentration of
sodium hydroxide
in mol / dm3
0.10
0.05
0.00
0 2 4 6 8 10 12
time / hours
(a) (i) Describe how the concentration of sodium hydroxide changes with time.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Determine the time it took for the concentration of sodium hydroxide to fall to 0.15 mol / dm3.
....................................................................................................................................... [1]
(iii) At what time was the reaction complete?
....................................................................................................................................... [1]
(iv) On the grid above, draw a line to show how the concentration of sodium hydroxide changes
when the concentration of 1-bromobutane in the reaction mixture is increased.
All other conditions remain the same.
[2]
(v) Increasing the concentration of 1-bromobutane increases the rate of this reaction.
Suggest one other way of increasing the rate of this reaction.
....................................................................................................................................... [1]
© UCLES 2014 0620/21/O/N/14

11
(b) The concentration of aqueous sodium hydroxide can be found by titrating samples of the
reaction mixture with hydrochloric acid.
Describe how you would carry out this titration.
In your answer, refer to:

● a burette,
● a volumetric pipette,
● an acid-base indicator solution.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
(c) Hydrochloric acid is made by dissolving hydrogen chloride gas, HCl, in water.
Draw a dot-and-cross diagram to show a molecule of hydrogen chloride.
Show hydrogen electrons as x.
Show chlorine electrons as ●.
[2]
[Total: 13]

12
7 Fertilisers usually contain compounds of nitrogen, phosphorus and potassium.
(a) Why do farmers use fertilisers?
.............................................................................................................................................. [1]
(b) Many fertilisers contain ammonium sulfate.

Ammonium sulfate is made by reacting aqueous ammonia with sulfuric acid.
What type of chemical reaction is this?
.............................................................................................................................................. [1]
(c) Aqueous ammonia reacts with nitric acid to make another compound often found in fertilisers.
State the name of this compound.
.............................................................................................................................................. [1]
(d) The structure of ammonium sulfate is shown below.
NH4+ NH4+ NH4+ NH4+
SO42– SO42–
NH4+ NH4+ NH4+ NH4+
SO42– SO42–
NH4+ NH4+ NH4+ NH4+
SO42– SO42–
Deduce the simplest ratio of ammonium and sulfate ions in ammonium sulfate.
.............................................................................................................................................. [1]
(e) Ammonium salts react with alkalis. For example:
ammonium sodium sodium

+ → + ammonia + water
sulfate hydroxide sulfate
Use this information to explain why adding slaked lime to fields which have fertilisers spread
on them may result in loss of nitrogen.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
© UCLES 2014 0620/21/O/N/14

13
(f) Many fertilisers contain potassium chloride.

When molten potassium chloride is electrolysed, two products are formed.
Complete the table below to show the name of the electrodes and the products formed.
charge on name of product formed

the electrode the electrode at the electrode
positive
negative
[3]
[Total: 9]

14
8 (a) A student placed a crystal of iodine in a test tube of solvent.

After two minutes, a dense violet colour was observed at the bottom of the test-tube. After
three hours, the violet colour had spread throughout the solvent.
solvent
at the after after

start 2 minutes 3 hours
Use the kinetic particle theory to explain these observations.
In your answer, refer to:

● the arrangement and motion of the molecules in the iodine crystal,
● the arrangement and motion of the molecules in the solution,
● the names of the processes which are occurring.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
(b) Astatine, At, is below iodine in Group VII of the Periodic Table.
(i) The table shows the states of the Group VII elements at room temperature.
element state
fluorine gas
chlorine gas
bromine liquid
iodine solid
Use this information to deduce the state of astatine at room temperature.
....................................................................................................................................... [1]
© UCLES 2014 0620/21/O/N/14

15
(ii) Astatine is radioactive. A lot of heat is given off due to this radioactivity.
The small samples of astatine that have been isolated are often liquid.
Suggest why they are often liquid.
....................................................................................................................................... [1]
(iii) Although few compounds of astatine have been made, scientists think that sodium astatide
will react with iodine.
Complete the equation for this reaction.
I2 + .....NaAt → 2NaI + ........

[2]
[Total: 8]

© UCLES 2014
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/21/O/N/14
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY

1 (a) (i) E [1]
(ii) A and D [1]
(iii) D [1]
(iv) B [1]
(v) D [1]
(vi) A and D [1]
(b) C2H4Br2 [1]
(c) 4 (H2O) [1]
5 (O2) [1]
note: mark dependent on 4 (H2O)
[Total: 9]
2 (a) (i) sodium / Na+ [1]
(ii) X is fluoride [1]
Y is nitrate [1]
(iii) 0.244 (mg) [1]

allow: 0.24
(iv) 4th box down ticked (weakly acidic) [1]
(b) (add nitric acid) add silver nitrate [1]
white precipitate [1]

note: mark dependent on correct reagent
(c) polymer [1]
monomer [1]
[Total: 9]

3 (a) ring around the OH group [1]
(b) bromine (water) [1]

allow: bromination
decolourised / turns colourless [1]

note: mark dependent on correct reagent
ignore: goes clear / gets discoloured
allow: potassium manganate(VII) / potassium permanganate (1)

turns colourless (1)
ignore: incorrect colour of reagent
(c) (i) to break up the cells / to extract the pigment / to separate the pigment from
the petals / idea of getting the colour out of the petals, e.g. otherwise the
colour won’t come out [1]
idea that solvent dissolves the pigment / idea of making a solution [1]
ignore: find out how pure the rose petals are / reference to separating
colours
(ii) pigment might be absorbed onto filter paper / pigment sticks to filter paper
[1]
(d) (i) chromatography [1]
(ii) spot near the bottom and above the solvent level [1]
(iii) to keep atmosphere in jar saturated (with solvent vapour) [1]

allow: to reduce / prevent (solvent) evaporation
(iv) A and C [1]
(e) structure of ethanol with ALL atoms and bonds shown [2]
[Total: 12]

4 (a) thermometer [1]
(b) Any two from: [2]
• same volume of water in can

• same height of burner (from can)
• wick same height
• same rate / amount of stirring of water
• allow: same temperature of water at start
• allow: same amount of fuels burnt / same temperature rise
• allow: same type of can
(c) so same temperature throughout the water / to stop differences in temperature in

the different parts of the water / otherwise the temperature will be higher at the
bottom (of the water) / so not hotter in one place [1]
ignore: to mix the water / so there are no convection currents
(d) decreases / goes down [1]
idea of liquid or fuel turning to vapour / gas; [1]

allow: gases formed
ignore: fuels evaporate
note: 2nd mark dependent on first
(e) F [1]
(f) (i) mixture of metals / mixture of metal(s) + non-metals [1]

do not allow: compound
(ii) covers surface / idea of protective layer [1]
prevents contact with air / prevents contact with water / so air (or water) does
no react with steel [1]
do not allow: reference to tin being more reactive / sacrificial protection (for
second marking point)
(g) 1st box down ticked (giant covalent) [1]
[Total: 11]

5 (a) Any four from: [4]
• suitable named metal / metal oxide e.g. reactive metal such as Mg / Zn or

• their oxides
• suitable named acid
• metal + acid gives metal salt / named metal gives named metal salt
• metal + acid gives off hydrogen
note: complete word equation for metal + acid → salt + hydrogen (2)
• metal oxide + acid gives metal salt / named metal oxide gives named metal
• salt
• water also product of reaction of metal oxide + acid
note: complete word equation for metal oxide + acid → salt + water (2)
(b) exothermic [1]
(c) suitable use of radioactive isotope e.g. detecting leaks in pipes / checking
thickness of paper / tracer / cancer treatment / investigating thyroid function [1]
ignore: atomic bombs / explosions
(d) protons 92 and 92 [1]
neutrons 143 and 146 [1]
electrons 92 and 92 [1]
[Total: 9]
6 (a) (i) (concentration) decreases [1]
then remains constant [1]

allow: levels out
(ii) 3.8 (hr) / 3 hr 48 min [1]
(iii) 9 (hr) [1]

allow: 8.8–9.2 (hr)
(iv) steeper graph line from same starting point [1]
levels off lower than 0.10 mol /dm3 [1]
(v) increase the temperature / increase concentration of sodium hydroxide [1]

allow: add a catalyst

(b) Any four from: [4]
• acid in burette
• use (volumetric) pipette to put sodium hydroxide into flask
allow: sodium hydroxide in burette / acid in flask
• idea of correct setup of apparatus, i.e.flask under burette
• indicator in flask
• run hydrochloric acid into sodium hydroxide
• until indicator changes colour
• any indication of good technique e.g. repeating experiment / add acid
• slowly / shaking flask after each addition of acid
note: answers must be in the correct context, e.g. do not allow indicator in
burette
(c) bonding pair of electrons between H and Cl and no additional electrons on the H
atom [1]
six non-bonding electrons around the chlorine atom [1]
ignore: inner shell electrons in Cl.
[Total: 13]
7 (a) for better crop / for better plant growth / to replace elements (or named elements
or minerals) lost from soil when crops harvested / for more plant protein [1]
allow: to give more nutrients to plants
ignore: for healthy plant growth / to give plants the compounds they need to grow
/ to help plants grow
(b) neutralisation acid-base (reaction) [1]
(c) ammonium nitrate [1]
(d) 2 NH4+ to 1 SO42– / 2 ammonium to 1 sulfate [1]

allow: 2:1 or 1:2 ratio unqualified
allow: (NH4)2SO4
(e) Any two from: [2]
• slaked lime can form an alkaline solution with water / slaked lime is calcium
• hydroxide / slaked lime is a hydroxide / slaked lime is basic
• slaked lime reacts with ammonium (salts)
allow:: slaked lime reacts with fertiliser
• ammonia escapes from soil / gas escapes from soil

(f) positive: anode and negative cathode [1]
at + electrode → chlorine [1]
at – electrode → potassium [1]
[Total: 9]
8 (a) Any four from: [4]
• dissolving
• diffusion
• in iodine solid the particles are close together
• in iodine solid the particles only vibrate ALLOW: particles do not move
• in solution the iodine molecules are further / far apart
• in solution the particles are randomly arranged/ no particular arrangement
• in solution, particles move (fairly) freely / in solution particles slide over
solvent molecules
allow: in solution particles move slowly (from place to place)
• in solution there is bulk movement of particles from higher to lower
concentration / particles spread out in solution / move everywhere / mix up
allow: particles move from higher to lower concentration
• ideas of explanation of dissolving in terms of solvent molecules getting
between the iodine particles
• ideas about forces between particles of iodine being weakened on dissolving
(b) (i) solid [1]
(ii) heat causes astatine to melt / energy causes astatine to melt [1]
allow:: the astatine has melted / radioactivity melts the astatine
(iii) At2 on right [1]
2 (NaAt) on left [1]

note: 2nd mark dependent on At2 or 2At on right
[Total: 8]

*5421214333*
CHEMISTRY 0620/31
1 hour 15 minutes

IB14 11_0620_31/2RP
2
1 (a) Match the following pH values to the solutions given below.
1 3 7 10 13
The solutions all have the same concentration.
solution pH
aqueous ammonia, a weak base ............
dilute hydrochloric acid, a strong acid ............
aqueous sodium hydroxide, a strong base ............
aqueous sodium chloride, a salt ............
dilute ethanoic acid, a weak acid ............

[5]
(b) Explain why solutions of hydrochloric acid and ethanoic acid with the same concentration, in
mol / dm3, have a different pH.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(c) Measuring pH is one way of distinguishing between a strong acid and a weak acid.
Describe another method.
method .......................................................................................................................................
....................................................................................................................................................
results ........................................................................................................................................
....................................................................................................................................................
[2]
[Total: 9]
© UCLES 2014 0620/31/O/N/14

3
2 Two macromolecular forms of carbon are graphite and diamond. The structures of graphite and
diamond are given below.
graphite diamond
(a) Explain in terms of its structure why graphite is soft and is a good conductor of electricity.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(b) State two uses of graphite which depend on the above properties.
It is soft ......................................................................................................................................
....................................................................................................................................................
It is a good conductor of electricity ............................................................................................
....................................................................................................................................................
[2]
(c) Silicon(IV) oxide also has a macromolecular structure.
(i) Describe the macromolecular structure of silicon(IV) oxide.
.............................................................................................................................................
....................................................................................................................................... [1]
(ii) Predict two physical properties which diamond and silicon(IV) oxide have in common.
.............................................................................................................................................
....................................................................................................................................... [2]
[Total: 8]

4
3 The main use of sulfur dioxide is the manufacture of sulfuric acid.
(a) State two other uses of sulfur dioxide.
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) One source of sulfur dioxide is burning sulfur in air.

Describe how sulfur dioxide can be made from the ore zinc sulfide.
....................................................................................................................................................
.............................................................................................................................................. [2]
(c) The Contact process changes sulfur dioxide into sulfur trioxide.
2SO2(g) + O2(g) 2SO3(g)

the forward reaction is exothermic
temperature 400 to 450 °C
low pressure 1 to 10 atmospheres
catalyst vanadium(V) oxide
(i) What is the formula of vanadium(V) oxide?
....................................................................................................................................... [1]
(ii) Vanadium(V) oxide is an efficient catalyst at any temperature in the range 400 to 450 °C.
Scientists are looking for an alternative catalyst which is efficient at 300 °C.
What would be the advantage of using a lower temperature?
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(iii) The process does not use a high pressure because of the extra expense.
Suggest two advantages of using a high pressure?
Explain your suggestions.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [4]
© UCLES 2014 0620/31/O/N/14

5
(d) Sulfuric acid is made by dissolving sulfur trioxide in concentrated sulfuric acid to form oleum.
Water is reacted with oleum to form more sulfuric acid.
Why is sulfur trioxide not reacted directly with water?
.............................................................................................................................................. [1]
[Total: 12]

6
4 Iron is extracted from the ore hematite in the Blast Furnace.
waste gases
raw materials:
coke, C
firebrick lining iron ore, Fe2O3
limestone, CaCO3
CO forms
CO2 forms
air
slag
molten iron
(a) The coke reacts with the oxygen in the air to form carbon dioxide.
C + O2 → CO2
(i) Explain why carbon monoxide is formed higher in the Blast Furnace.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Write an equation for the reduction of hematite, Fe2O3, by carbon monoxide.
....................................................................................................................................... [2]
(b) (i) Limestone decomposes to form two products, one of which is calcium oxide.
Name the other product.
....................................................................................................................................... [1]
(ii) Calcium oxide reacts with silicon(IV) oxide, an acidic impurity in the iron ore, to form slag.
Write an equation for this reaction.
....................................................................................................................................... [2]
(iii) Explain why the molten iron and the molten slag form two layers and why molten iron is
the lower layer.
.............................................................................................................................................
....................................................................................................................................... [2]
(iv) Suggest why the molten iron does not react with the air.
....................................................................................................................................... [1]
© UCLES 2014 0620/31/O/N/14

7
(c) Iron and steel rust. Iron is oxidised to hydrated iron(III) oxide, Fe2O3.2H2O, which is rust.
(i) Name the two substances which cause iron to rust.
....................................................................................................................................... [1]
(ii) Explain why an aluminium article coated with aluminium oxide is protected from further
corrosion but a steel article coated with rust continues to corrode.
.............................................................................................................................................
....................................................................................................................................... [1]
(d) There are two electrochemical methods of rust prevention.
(i) The first method is sacrificial protection.
Explain why the steel article does not rust.
steel pipe
connected block of zinc
electrically
to steel pipe
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [4]
The second method is to make the steel article the cathode in a circuit for electrolysis.
power
– +
steel girder
inert anode
bubbles of
hydrogen gas sea-water
(ii) Mark on the diagram the direction of the electron flow. [1]
(iii) The steel girder does not rust because it is the cathode. Reduction takes place at the
cathode. Give the equation for the reduction of hydrogen ions.
....................................................................................................................................... [2]
[Total: 19]

8
5 Three common pollutants in the air are carbon monoxide, the oxides of nitrogen, NO and NO2, and
unburnt hydrocarbons. They are all emitted by motor vehicles.
(a) Describe how the oxides of nitrogen are formed.
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) Describe how a catalytic converter reduces the emission of these three pollutants.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
(c) Other atmospheric pollutants are lead compounds from leaded petrol.
Explain why lead compounds are harmful.
....................................................................................................................................................
.............................................................................................................................................. [1]
[Total: 7]
© UCLES 2014 0620/31/O/N/14

9
6 Esters, polyesters and fats all contain the ester linkage.
(a) Esters can be made from alcohols and carboxylic acids. For example, the ester ethyl ethanoate
can be made by the following reaction.
CH3COOH + CH3CH2OH → CH3COOCH2CH3 + H2O
(i) Name the carboxylic acid and the alcohol from which the following ester could be made.
CH3 CH2 CH2 C
O CH3
name of carboxylic acid ......................................................................................................
name of alcohol ..................................................................................................................

[2]
(ii) 6.0 g of ethanoic acid, Mr = 60, was reacted with 5.5 g of ethanol, Mr = 46.
Determine which is the limiting reagent and the maximum yield of ethyl ethanoate, Mr = 88.
number of moles of ethanoic acid = .............................................................................. [1]
number of moles of ethanol = ....................................................................................... [1]
the limiting reagent is .................................................................................................... [1]
number of moles of ethyl ethanoate formed = .............................................................. [1]
maximum yield of ethyl ethanoate = ............................................................................. [1]
(b) The following two monomers can form a polyester.
HOOC COOH HO OH
Draw the structural formula of this polyester. Include two ester linkages.
[3]

10
(c) Fats and vegetable oils are esters. The formulae of two examples of natural esters are given
below.
CH2 CO2 C17H33 CH2 CO2 C17H35
CH CO2 C17H33 CH CO2 C17H35
CH2 CO2 C17H33 CH2 CO2 C17H35
ester 1 ester 2
(i) One ester is saturated, the other is unsaturated.

Describe a test to distinguish between them.
test ......................................................................................................................................
result with unsaturated ester ..............................................................................................
.............................................................................................................................................
result with saturated ester ..................................................................................................
.............................................................................................................................................
[3]
(ii) Deduce which one of the above esters is unsaturated. Give a reason for your choice.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(iii) Both esters are hydrolysed by boiling with aqueous sodium hydroxide.
What types of compound are formed?
............................................................... and .............................................................. [2]
[Total: 17]
© UCLES 2014 0620/31/O/N/14

11
7 Nitrogen can form ionic compounds with reactive metals and covalent compounds with non-metals.
(a) Nitrogen reacts with lithium to form the ionic compound lithium nitride, Li3N.
(i) Write the equation for the reaction between lithium and nitrogen.
....................................................................................................................................... [2]
(ii) Lithium nitride is an ionic compound. Draw a diagram which shows its formula, the charges
on the ions and the arrangement of the valency electrons around the negative ion.
Use x for an electron from a lithium atom.

Use o for an electron from a nitrogen atom.
[2]
(b) Nitrogen fluoride is a covalent compound.
(i) Draw a diagram showing the arrangement of the valency electrons in one molecule of the
covalent compound nitrogen trifluoride, NF3.
Use x for an electron from a nitrogen atom.

Use o for an electron from a fluorine atom.
[2]
(ii) Lithium nitride has a high melting point, 813 °C. Nitrogen trifluoride has a low melting point,
–207 °C.
Explain why the melting points are different.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
[Total: 8]

© UCLES 2014
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
12
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/31/O/N/14
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY

1 (a) Match the following pH values to the solutions given below.
1 3 7 10 13
The solutions all have the same concentration.
solution pH
aqueous ammonia, weak base 10
dilute hydrochloric acid, a strong acid 1
aqueous sodium hydroxide, a strong base 13
aqueous sodium chloride, a salt 7
dilute ethanoic acid, a weak acid 3 [5]
(b) Hydrochloric acid strong acid or ethanoic acid weak acid [1]
OR: hydrochloric acid completely ionised or ethanoic acid
partially ionised
hydrochloric acid greater concentration of/more H+ ions (than ethanoic acid) [1]
(c) Rate of reaction with Ca, Mg, Zn, Fe [1]
Strong (hydrochloric) acid bubbles faster or more bubbles or dissolves faster [1]
OR: rate of reaction with (metal) carbonate [1]

strong (hydrochloric) acid faster or more bubbles or dissolves faster (only if
carbonate insoluble) [1]
OR: electrical conductivity [1]

strong (hydrochloric) acid better conductor [1]
[Total: 9]
2 (a) soft because weak forces between layers/sheets/rows [1]
layers can slip/slide [1]
good conductor because electrons can move/mobile [1]
(b) it is soft: pencils or lubricant or polish [1]

good conductor: electrodes or brushes (in electric motors) [1]
(c) (i) every silicon atom is bonded/attached to 4 oxygen atoms or every oxygen
bonded/attached to two silicon atoms [1]
(ii) Any two from:

high melting point/boiling point
hard
colourless crystals/shiny
poor/non-conductor of electricity/insulator
insoluble in water [2]
[Total: 8]

3 (a) Any two from:

bleach/making wood pulp/making paper
food/fruit juice/wine preservative
fumigant/sterilising/insecticide [2]
(b) heating/roasting/burning (zinc sulfides) [1]

in air/oxygen COND on M1 [1]
(c) (i) V2O5 [1]
(ii) position of equilibrium shifts right/yield increases [1]

to save energy [1]
(iii) faster reaction/rate [1]
more collisions per second/higher collision frequency [1]
fewer moles/molecules (of gas) on right [1]
(so) position of equilibrium shifts right/yield increases [1]
(d) (the reaction is) too violent/too exothermic or produces mist/fumes (of acid) [1]
[Total: 12]
4 (a) (i) insufficient/limited oxygen [1]

or 2C + O2 → 2CO
coke/carbon reacts with carbon dioxide [1]

or C + CO2 → 2CO
(ii) Fe2O3 + 3CO → 2Fe + 3CO2

species (1) balancing (1) [2]
(b) (i) carbon dioxide [1]
(ii) CaO + SiO2 → CaSiO3 [2]

[1] each side correct
(iii) (molten) iron higher density (than slag) [2]
(iv) No oxygen in contact with iron or layer of slag prevents hot iron reacting with
oxygen/air or (all) oxygen reacts with carbon (so no oxygen left to react with
iron) [1]
(c) (i) air/oxygen and water (need both) [1]

(ii) aluminium oxide layer is impervious or non-porous or passive or unreactive

or will not allow water/air to pass through it (rust allows passage of water or
air or it flakes off) [1]
(d) (i) zinc more reactive (than iron/steel) [1]

loses electrons [1]
electrons move (from zinc) to iron [1]
Zinc reacts (with air and water) or zinc corrodes or zinc is oxidised or zinc is
anodic or zinc forms positive ions or zinc forms Zn2+ or iron and steel don’t
react with air/water or iron and steel are not oxidised or iron and steel do not
form ions or iron and steel do not lose electrons or iron and steel are
cathodic [1]
(ii) R to L in wire [1]
(iii) 2H+ + 2e– → H2

species (1) balancing (1)
[Total: 19]
5 (a) nitrogen and oxygen react [1]

at high temperatures (in engine) [1]
(b) M1 carbon monoxide (converted to) carbon dioxide or 2CO + O2 → 2CO2 [1]
M2 (by) oxides of nitrogen (which are reduced to) nitrogen

or 2NO → N2 + O2 or 2NO2 → N2 + 2O2 [1]
M3 hydrocarbons (burn) making water [1]
M4 products: any two from:

carbon dioxide, water, nitrogen [1]
(c) lead compounds are toxic or brain damage or reduce IQ or nausea or kidney
failure or anaemia [1]
[Total: 7]
6 (a) (i) butanoic acid [1]

methanol [1]
(ii) number of moles of ethanoic acid = 0.1 [1]

number of moles of ethanol = 0.12(0) [1]
the limiting reagent is ethanoic acid [1]
number of moles of ethyl ethanoate formed = 0.1 [1]
maximum yield of ethyl ethanoate is 8.8 g [1]

(b) correct ester linkage [1]

two ester linkages (COND on M1) [1]
continuation (COND on M2) [1]
(c) (i) add bromine water/bromine [1]

turns colourless [1]
remains brown/orange/reddish brown/yellow [1]
ALLOW: potassium manganate(VII) (acidic or alkaline) [1]

correct colour colourless/green or brown ppt [1]
stays pink/purple [1]
(ii) ester 1 [1]

COND alkyl group is CnH2n+1 which is NOT C17H33
or C17H35 is CnH2n+1 or less hydrogen [1]
(iii) soap or (sodium) salt (of a carboxylic acid) or carboxylate [1]
alcohol [1]
[Total: 17]
7 (a) (i) 6Li + N2 = 2Li3N

species (1) balancing (1)
(ii) N3– ion drawn correctly [1]
Charges correct (minimum 1 × Li ion and 1 nitride ion) [1]
(b) (i) 3 × shared pairs between N and 3 × F [1]
only 2 non-bonding electrons on N, 6 non-bonding electrons on each F

(COND on first point) [1]
(ii) Strong attractive forces/strong ionic bonds in lithium nitride [1]
weak (attractive) forces between molecules in NF3 [1]
[Total: 8]

CHEMISTRY 0620/51
*1100683816*
indicated on pages 2 and 3 in order to satisfy themselves that the supplied materials are satisfactory.
where relevant.
by phone: +44 1223 553554,
by fax: +44 1223 553558,
IB14 11_0620_51CI/3RP
2
For Question 1
(b) one 50 cm3 burette with stand and clamp
(d) 100 cm3 of aqueous hydrochloric acid of concentration 0.1 mol / dm3, labelled solution A
(e) 100 cm3 of aqueous hydrochloric acid of concentration 0.4 mol / dm3, labelled solution B
[H] (f) 100 cm3 of aqueous sodium hydroxide of concentration 0.1 mol / dm3, labelled solution C
[H] (g) methyl orange indicator
(i) a white tile
(j) one funnel for filling the burette
(k) teat pipette
© UCLES 2014 0620/51/CI/O/N/14

3
For Question 2
[H] (a) a stoppered test-tube containing about 1 g of chromium(III) potassium sulfate,

KCr(SO4)2.12H2O, labelled solid D
(b) one boiling tube and stopper
(c) access to water and distilled water
(d) splints
(e) rack of test-tubes including two hard glass test-tubes
(f) aqueous barium nitrate of suitable concentration to give a positive sulfate test
[N][H] (g) aqueous silver nitrate of suitable concentration to give a positive halide test
[C] (h) aqueous nitric acid of concentration 1 mol / dm3
[C] (i) aqueous sodium hydroxide of concentration 1 mol / dm3
(j) hydrogen peroxide solution of concentration 10 volume
(k) aqueous ammonia of concentration 1 mol / dm3
(l) a 10 cm3 measuring cylinder
(m) a Bunsen burner and matches
(n) teat pipettes
(o) test-tube holder

4
© UCLES 2014 0620/51/CI/O/N/14

5

6
© UCLES 2014 0620/51/CI/O/N/14

7
NOVEMBER 2014
penalised.
© UCLES 2014 0620/51/CI/O/N/14

[Turn over
8
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
© UCLES 2014 0620/51/CI/O/N/14

*3364232586*
CHEMISTRY 0620/51
1 hour 15 minutes

Total
IB14 11_0620_51/2RP
2
1 You are going to investigate the reaction between two different solutions of dilute hydrochloric acid,
A and B, and a solution of substance C which is an alkali.
Instructions
(a) Experiment 1
Fill the burette with the solution A of dilute hydrochloric acid to the 0.0 cm3 mark. Using a
measuring cylinder, pour 20 cm3 of solution C into the conical flask. Add a few drops of methyl
orange to the flask.
Add solution A to the flask, with shaking. Continue to add solution A to the flask until the
mixture just changes colour. Record the burette reading in the table and complete the table.
Pour away the contents of the conical flask and rinse the flask with distilled water.
difference / cm3
[3]
(b) Experiment 2
Empty the burette and rinse it first with distilled water, and then with a little of solution B. Fill the
burette with the solution B of dilute hydrochloric acid to the 0.0 cm3 mark.
Repeat Experiment 1 using solution B.
Record the burette readings in the table and complete the table.
difference / cm3
[3]
© UCLES 2014 0620/51/O/N/14

3
(c) (i) What colour change was observed when dilute hydrochloric acid was added to solution C?
from ............................................................ to ............................................................. [1]
(ii) Why is methyl orange added to the flask?
....................................................................................................................................... [1]
(iii) What type of chemical reaction takes place when hydrochloric acid reacts with alkaline
solutions?
....................................................................................................................................... [1]
(d) (i) In which experiment was the greater volume of dilute hydrochloric acid used?
....................................................................................................................................... [1]
(ii) Compare the volumes of dilute hydrochloric acid used in Experiments 1 and 2.
....................................................................................................................................... [1]
(iii) Suggest, in terms of the concentration of solutions A and B, an explanation for the
difference in volumes used.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(e) If Experiment 2 was repeated using 10 cm3 of solution C, what volume of dilute hydrochloric
acid would be used? Explain your answer.
....................................................................................................................................................
.............................................................................................................................................. [2]
(f) Give one advantage and one disadvantage of using a measuring cylinder for solution C.
advantage ..................................................................................................................................
disadvantage .............................................................................................................................
[2]

4
(g) Describe a method other than titration, using a different reactant, that could be used to
compare the concentrations of the two solutions of dilute hydrochloric acid, A and B.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
[Total: 21]
© UCLES 2014 0620/51/O/N/14

5
2 You are provided with solid D which is a salt.

Carry out the following tests on solid D, recording all of your observations in the table.
tests observations
tests on the solid
(a) (i) Describe the appearance of solid D. ...........................................................................
..................................................................... [2]
(ii) Place about half of solid D into a test-tube. ...........................................................................

Heat the test-tube gently and then strongly.
Leave to stand for two minutes. ...........................................................................
..................................................................... [2]
tests on the aqueous solution
Add the rest of solid D to about 10 cm3 of distilled

water in a boiling tube and shake to dissolve. Divide
the solution into five equal portions in separate
test-tubes.
(b) (i) Using a teat pipette, add several drops

of aqueous sodium hydroxide to the first
portion of the solution. ..................................................................... [2]
Now add excess aqueous sodium

hydroxide to the mixture. ..................................................................... [1]
(ii) Using a teat pipette, add several drops of

aqueous ammonia to the second portion ...........................................................................
of the solution. Now add excess aqueous
ammonia to the mixture. ..................................................................... [2]

6
tests observations
(c) To the third portion of the solution, add about ...........................................................................

1 cm3 of hydrogen peroxide solution. Heat
the mixture to boiling. Leave to stand for one ...........................................................................
minute. Test any gases given off with a splint.
..................................................................... [3]
(d) To the fourth portion of the solution, add about

1 cm3 of dilute nitric acid and aqueous silver
nitrate. ..................................................................... [1]
(e) To the fifth portion of solution, add about 1 cm3 ...........................................................................

of dilute nitric acid and aqueous barium nitrate.
Shake and leave to stand for one minute. ..................................................................... [2]
(f) What does test (a)(ii) tell you about solid D?
.............................................................................................................................................. [1]
(g) What conclusions can you draw about the identity of solid D?
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 19]
© UCLES 2014 0620/51/O/N/14

7
BLANK PAGE
© UCLES 2014 0620/51/O/N/14

8
Test for anions

produced

aluminium (Al 3+)
Test for gases

© UCLES 2014 0620/51/O/N/14

0620 CHEMISTRY

1 (a) Table of results for Experiment 1

initial and final volumes and difference completed correctly (1)
(b) Table of results for Experiment 2

Initial and final volumes completed correctly (1)
and difference (1)
(c) (i) yellow, not orange to pink / orange (1) not red [1]
(ii) as an indicator / to show end point (1)

ignore to see colour change [1]
(iii) neutralisation (1) [1]
(d) (i) experiment 1 (1) [1]

allow: ecf from tables
(ii) quantitative comparison

experiment 1 4X volume experiment 2/x cm3 more than (1) [1]
(iii) solution B more concentrated/stronger (1) or converse

explanation e.g. 4X as concentrated/less volume used (1) [2]
(e) half value / half value from table result for experiment 2 (1) cm3 (1) [2]
(f) advantage
easy to use / quick / convenient (1)
disadvantage
not accurate (1) [2]
(g) same volume of each solution (1) add suitable named reactant (1)
expected observation (1) comparison (1)
e.g. 10 cm3 of each acid (1) add strip of magnesium/named carbonate (1)
effervescence (1) more rapid bubbles means stronger acid (1) [4]

2 (a) (i) purple / black / violet (1) crystals (1) [2]
(ii) drops / condensation at top of tube (1) colour change to green/grey (1)
green on cooling (1) max [2]
(b) (i) green / grey (1) not white

precipitate (1) [2]
dissolves / clears (1) [1]
(ii) green / grey not white precipitate (1) insoluble (1) [2]
(c) blue / green (1) glowing splint (1) relights / glows brighter (1)
effervescence / bubbles (1) max [3]
(d) no reaction / no precipitate / no change / colourless solution (1) [1]
(e) white (1) precipitate (1) [2]
(f) hydrated/water (1)

allow transition metal [1]
(g) not halide / chloride / iodide (1) sulfate (1)

transition metal / iron / chromium / catalyst (1) [3]

*9261581316*
CHEMISTRY 0620/61
1 hour

IB14 11_0620_61/3RP
2
1 A student reacted dilute nitric acid with lead(II) oxide to prepare lead(II) nitrate. The diagram shows
the stages in the method used.
2 Lead(II) oxide
was added until
all the nitric acid
had reacted
1 50 cm3 of dilute nitric
acid was measured into
a beaker
DILUTE
NITRIC
ACID
heat
4 The solution was

allowed to cool
3 The mixture
was separated
solution of
lead(II) nitrate
(a) Complete the boxes to identify the pieces of apparatus. [2]
(b) Why is the dilute nitric acid heated?
.............................................................................................................................................. [1]
(c) The lead(II) oxide was weighed before and after the additions.
19 15
18 14
17 13
16 g 12 g
before after
Use the balance diagrams to work out the mass of lead(II) oxide added to the dilute nitric acid.
.............................................................................................................................................. [2]
© UCLES 2014 0620/61/O/N/14

3
(d) (i) How would the student know when all of the dilute nitric acid had reacted in stage 2?
....................................................................................................................................... [1]
(ii) What method is used to separate the mixture in stage 3?
....................................................................................................................................... [1]
(iii) What term is used to describe the unreacted lead(II) oxide?
....................................................................................................................................... [1]
(e) Describe the effect of heating the solution of lead(II) nitrate until it boils and then heating for a
further ten minutes.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 10]

4
2 Two experiments were carried out to show what factors affect the rate of decomposition of hydrogen
peroxide, H2O2.
In each experiment the volume of gas produced was measured every minute for ten minutes.
Experiment 1
The student used a mixture of 50 cm3 of hydrogen peroxide, 50 cm3 of water and
1 g of manganese(IV) oxide at a room temperature of 20 °C.
The results were plotted to obtain the graph shown.
Experiment 2
The student repeated Experiment 1 but did not record how much of each substance was used. The
points were plotted on the grid.
80 Experiment 2
70
60
50
volume of
gas / cm3
40 Experiment 1
30
20
10
0
0 1 2 3 4 5 6 7 8 9 10
time / minutes
© UCLES 2014 0620/61/O/N/14

5
(a) Complete the graph for Experiment 2. [1]
(b) Suggest the composition of the mixture used in Experiment 2. Explain your suggestion.
composition ...............................................................................................................................
....................................................................................................................................................
explanation ................................................................................................................................
.............................................................................................................................................. [4]
(c) What is the function of the manganese(IV) oxide?
.............................................................................................................................................. [1]
(d) Sketch on the grid the curve that you would expect if Experiment 1 was repeated at 10 °C. [2]
[Total: 8]
3 A student investigated the colours present in a fruit drink. The fruit drink was tested to check that
no artificial colours had been added. The apparatus below was used.
glass cover
beaker
paper
solvent
(a) (i) Name the method used.
....................................................................................................................................... [1]
(ii) Why is there a glass cover on the beaker?
....................................................................................................................................... [1]
(b) When should the paper be removed from the beaker?
.............................................................................................................................................. [1]

6
(c) The diagram shows the results of the experiment.
solvent front
colours from
artificial colours fruit drink
(i) How many different coloured compounds were present in the fruit drink?
....................................................................................................................................... [1]
(ii) Are there any of the artificial colours present in the fruit drink? Explain your answer.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
[Total: 6]
© UCLES 2014 0620/61/O/N/14

7
4 A student investigated the reaction between two different solutions of dilute hydrochloric acid, A
and B, and solution C which is alkaline.
(a) Experiment 1
A burette was filled with solution A of dilute hydrochloric acid to the 0.0 cm3 mark. Using a
measuring cylinder, 20 cm3 of solution C was poured into a conical flask. A few drops of methyl
orange were added to the flask.
Solution A was added to the flask, with shaking, until the mixture just changed colour.
Use the burette diagram to record the burette reading in the table and complete the table.
24
25
26
initial reading

difference / cm3
[2]
(b) Experiment 2
The burette was emptied and rinsed, first with distilled water, and then with a little of
solution B. The burette was filled with solution B of dilute hydrochloric acid to the 0.0 cm3 mark.
Experiment 1 was repeated using solution B.

Use the burette diagram to record the burette reading in the table and complete the table.
final reading

difference / cm3
[2]

8
(c) (i) What type of chemical reaction takes place when hydrochloric acid reacts with alkaline
solutions?
....................................................................................................................................... [1]
(ii) Why is methyl orange added to the flask?
....................................................................................................................................... [1]
(d) Why was the burette rinsed, first with distilled water and then with solution B, before starting
Experiment 2?
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(e) (i) In which experiment was the greater volume of dilute hydrochloric acid used?
....................................................................................................................................... [1]
(ii) Compare the volumes of dilute hydrochloric acid used in Experiments 1 and 2.
....................................................................................................................................... [1]
(iii) Suggest, in terms of the concentration of solutions A and B, an explanation for the
difference in volumes used.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(f) If Experiment 2 was repeated using 10 cm3 of solution C, what volume of dilute hydrochloric
acid would be used? Explain your answer.
....................................................................................................................................................
.............................................................................................................................................. [2]
(g) Give one advantage and one disadvantage of using a measuring cylinder for solution C.
advantage ..................................................................................................................................
disadvantage ....................................................................................................................... [2]
© UCLES 2014 0620/61/O/N/14

9
(h) Describe a method other than titration, using a different reactant, that could be used to
compare the concentrations of the two solutions of dilute hydrochloric acid, A and B.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
[Total: 20]

10
5 A solid D, which is a soluble metal sulfate, was analysed.

The tests on D, and some of the observations, are in the following table.
tests observations
tests on solid D
(a) (i) Appearance of solid D. pale green crystals
(ii) Solid D was heated in a

test-tube gently and then condensation formed at the top of the test-tube
strongly.
tests on the aqueous solution
Solid D was added to distilled water

and shaken to dissolve. The solution
was divided into four equal portions in
(b) (i) Several drops of aqueous

sodium hydroxide were added green precipitate
to the first portion of the solution.
Excess aqueous sodium

hydroxide was added to the green precipitate remained
mixture.
(ii) Excess aqueous ammonia was

added to the second portion of green precipitate
the solution.
(c) Aqueous silver nitrate and dilute

nitric acid were added to the third
portion of the solution. ...................................................................................... [1]
(d) Aqueous barium nitrate and dilute

nitric acid were added to the fourth
portion of the solution. ...................................................................................... [2]
© UCLES 2014 0620/61/O/N/14

11
(e) What does test (a) tell you about solid D?
.............................................................................................................................................. [2]
(f) What conclusions can you draw about the identity of solid D?
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 8]
6 Fizzy water
Fizzy water contains carbon dioxide dissolved under pressure. When the water is heated, the gas
is given off.
(a) (i) Complete the labelled diagram to show how you could collect and measure the volume of
gas given off when fizzy water is heated.
fizzy
water
heat
[2]
(ii) State a test for carbon dioxide.
.............................................................................................................................................
....................................................................................................................................... [2]

12
(b) A label on a bottle of fizzy water stated that ‘when evaporated completely the mass of solid
residue remaining is 200 mg / dm3 of water’.
Plan an experiment to check the mass of solid formed when the fizzy water is completely
evaporated. You are provided with a 500 cm3 bottle of fizzy water. You can use the space below
to draw a diagram of the apparatus used if you wish.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
[Total: 8]
© UCLES 2014 0620/61/O/N/14

0620 CHEMISTRY
Cambridge is publishing the mark schemes for the October / November 2014 series for

Cambridge IGCSE – October / November 2014 0620 61
1 (a) boxes completed to show stirrer / glass rod (1)

watchglass / evaporating dish (1) [2]
(b) to speed up the reaction (1) [1]
(c) correct answer 4.2 g (2)

if incorrect, evidence of 17.8 – 13.6 (1) [2]
(d) (i) solid / lead oxide visible / remaining (1) [1]

do not allow: mention of precipitate
(ii) filtration (1) [1]
(iii) excess (1) [1]

allow: residue
(e) Any two from:

evaporation / steam (1)
solid / crystals formed (1)
breakdown / decomposition of solid (1) [2]
2 (a) smooth curve missing anomalous point (1) [1]
(b) composition of mixture

double volume / 100 cm3 of hydrogen peroxide (1)
more than 1 g of manganese(IV) oxide / powdered (1) [2]
ignore: references to water
note: double the concentration is valid for (2)
explanation
double volume of gas (1)
faster reaction (1) [2]
(c) catalyst / increase the rate of the reaction (1) [1]
(d) sketch graph less steep than original for Experiment 1 (1)
to same level (1) [2]
3 (a) (i) chromatography (1) [1]
(ii) to prevent loss / evaporation of solvent (1) [1]
(b) when the solvent is near the top of the paper / before the solvent reaches the top of the
paper (1) [1]

(c) (i) 4 (1) [1]
(ii) yes, one artificial dye (1)

at same height / matches (1) [2]

initial volume completed correctly (1)
0 or 24.4
all readings to 1 decimal place (1) [2]

final volume completed correctly (1)
6.1
difference correct (1) [2]
(c) (i) neutralisation (1) [1]

allow: acid-base
(ii) as an indicator / to show end point (1) [1]
(d) water to remove the solution A of acid (1)

acid B to remove traces of water (1) [2]
(e) (i) Experiment 1

ecf from readings (1) [1]
(ii) any correct comparison (1) [1]
(iii) solution B more concentrated / stronger (1) or converse

less volume was needed (1) [2]
(f) half value from table result for experiment 2 (1)

cm3 (1) [2]
(g) advantage: easy to use / quick / convenient (1)

disadvantage: not accurate owtte (1) [2]
(h) same volume of each solution (1)

add suitable reactant (1)
expected observation (1)
comparison (1) [4]
note: e.g. 10 cm3 of each acid (1), add strip of magnesium / named carbonate (1)
effervescence (1), more rapid bubbles means stronger acid (1)

5 (c) no reaction / no change / no precipitate (1) [1]
(d) white (1)

precipitate (1) [2]
(e) transition metal present (1)

allow: iron
water / hydrated (1) [2]
(f) hydrated (1) iron (1) (II) (1) (sulfate) [3]
6 (a) (i) gas syringe / inverted measuring cylinder in trough of water (1)
labelled (1) [2]
(ii) limewater (1)

milky (1) [2]
(b) measured volume of water (1)

in named weighed container (1)
evaporate to dryness (1)
reweigh / measure mass of solid (1)
conclusion: e.g. double the mass of residue if 500 cm3 water used to check mass in
1000 cm3 (1) max [4]

CHEMISTRY 0620/11
45 Minutes
Soft clean eraser
*8079009177*

The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level1/Level 2 Certificate.
IB14 06_0620_11/2RP
2
1 The diagram shows the result of dropping a purple crystal into water.
water purple
after five hours solution
purple
crystal
Which processes take place in this experiment?
chemical
diffusing dissolving
reaction
A
B
C
D
2 The four pieces of apparatus shown below are used in chemical experiments.
burette measuring pipette thermometer

cylinder
Which statement about the apparatus is correct?
A The burette measures the volume of liquid added in a titration.

B The measuring cylinder measures the mass of a substance used in an experiment.
C The pipette measures the volume of gas given off in a reaction.
D The thermometer measures the density of a solution.
© UCLES 2014 0620/11/M/J/14

3
3 Alcohol and water are completely miscible. This means when mixed together they form only one
liquid layer.
Which method is used to separate alcohol from water?
A crystallisation
B filtration
C fractional distillation
D precipitation
4 The diagram shows the structure of an atom of element X.
e
key
e e e = electron
n = neutron
5p p = proton
6n
= nucleus
e e
What is X?
A boron
B carbon
C sodium
D sulfur

4
5 The diagrams show four particles.
1 2
e e
e e
2p 3p key
2n 3n e = an electron
n = a neutron
e e
p = a proton
= nucleus
3 4
e e
e e
3p 3p
3n 4n
e e
e
Which two diagrams show atoms that are isotopes of each other?
6 The ‘lead’ in a pencil is made of a mixture of graphite and clay.
‘lead’
When the percentage of graphite is increased, the pencil slides across the paper more easily.
Which statement explains this observation?
A Graphite has a high melting point.

B Graphite is a form of carbon.
C Graphite is a lubricant.
D Graphite is a non-metal.
© UCLES 2014 0620/11/M/J/14

5
7 Element X is in Group I of the Periodic Table. X reacts with element Y to form an ionic compound.
Which equation shows the process that takes place when X forms ions?
A X + e – → X+
B X – e – → X–
C X + e – → X–
D X – e – → X+
8 Solid F is an element.
Solid G is a compound.
Neither solid conducts electricity but G conducts electricity when dissolved in water.
These properties suggest that F is ……1…… and that G is ……2…… with ……3…… bonds.
1 2 3
A diamond AgCl covalent

B diamond NaCl ionic
C graphite AgCl ionic
D graphite NaCl covalent
9 A compound contains one atom of calcium, two atoms of hydrogen and two atoms of oxygen.
What is the correct chemical formula of the compound?
A CaO2H2 B HOCaOH C H2CaO2 D Ca(OH)2
10 In athletics, banned drugs such as nandrolone have been taken illegally to improve performance.
Nandrolone has the molecular formula C18H26O2.
What is the relative molecular mass, Mr, of nandrolone?
(Relative atomic mass: H = 1; C = 12; O = 16)
A 46 B 150 C 274 D 306
11 Which substance will not conduct electricity?
A aluminium
B copper
C plastic
D steel

6
12 Which products are formed at the anode and cathode when electricity is passed through molten
lead(II) bromide?
anode (+) cathode (–)
A bromide ions lead ions

B bromine molecules lead atoms
C lead atoms bromine molecules
D lead ions bromide ions
13 Some reactions are endothermic.
How does the temperature and energy change in an endothermic reaction?
temperature change energy change
A decreases energy taken in

B decreases energy given out
C increases energy taken in
D increases energy given out
14 Two chemical processes are described below.
● In the combustion of methane, energy is ......1...... .
● In the electrolysis of molten lead(II) bromide, energy is ......2...... .
1 2
A given out given out

B given out taken in
C taken in given out
D taken in taken in
15 Which equation shows an oxidation reaction?
A C + O2 → CO2
B CaCO3 → CaO + CO2
C CaO + 2HCl → CaCl 2 + H2O
D N2O4 → 2NO2
© UCLES 2014 0620/11/M/J/14

7
16 In separate experiments, a catalyst is added to a reaction mixture and the temperature of the
mixture is decreased.
What are the effects of these changes on the rate of the reaction?
catalyst temperature
added decreased
A faster faster
B faster slower
C slower faster
D slower slower
17 An experiment is carried out to investigate the rate of reaction when calcium carbonate is reacted
with hydrochloric acid.
The volume of carbon dioxide gas given off is measured at different intervals of time.
The diagram shows pieces of apparatus used to collect gases.
1 2 3
downward delivery gas measuring over water in
syringe graduated tube
Which apparatus is suitable to collect and measure the volume of the carbon dioxide?
A 1, 2 and 3 B 2 and 3 only C 1 only D 3 only

8
18 The equation shows a reaction that is reversed by changing the conditions.
forward reaction
How can the forward reaction be reversed?
by adding water by heating
A
B
C
D
19 Which statements about alkalis are correct?
1 When reacted with an acid, the pH of the alkali increases.

2 When tested with litmus, the litmus turns blue.
3 When warmed with an ammonium salt, ammonia gas is given off.
20 Only two elements are liquid at 20 °C. One of these elements is shiny and conducts electricity.
This suggests that this element is a ......1...... and therefore its oxide is ......2...... .
1 2
A metal acidic
B metal basic
C non-metal acidic
D non-metal basic
21 Which acid reacts with ammonia to produce the salt ammonium sulfate?
A hydrochloric
B nitric
C phosphoric
D sulfuric
© UCLES 2014 0620/11/M/J/14

9
22 Aqueous sodium hydroxide is added to solid X and the mixture is heated.
A green precipitate is formed and an alkaline gas is given off.
Which ions are present in X?
A NH4+ and Fe2+

B NH4+ and Fe3+
C OH– and Fe2+
D OH– and Fe3+
23 Which statement about the Periodic Table is correct?
A Elements in the same period have the same number of outer electrons.
B The elements on the left are usually gases.
C The most metallic elements are on the left.
D The relative atomic mass of the elements increases from right to left.
24 Why is argon gas used to fill electric lamps?
A It conducts electricity.
B It glows when heated.
C It is less dense than air.
D It is not reactive.
25 An element melts at 1455 °C, has a density of 8.90 g / cm3 and forms a green chloride.
Where in the Periodic Table is this element found?

10
26 The diagrams show two items that may be found in the home. Each item contains zinc.
zinc plated bucket brass door-knocker
In which is zinc used as an alloy?
bucket door-knocker
A
B
C
D
27 In an experiment, three test-tubes labelled X, Y and Z were half-filled with dilute hydrochloric
acid. A different metal was added to each test-tube. After a few minutes the following
observations were made.
In tube X, bubbles slowly rose to the surface.

In tube Y, there was a rapid release of bubbles.
In tube Z, no bubbles were produced.
Which three metals match the observations?
tube X tube Y tube Z
A copper zinc iron

B magnesium iron copper
C zinc magnesium copper
D zinc magnesium iron
© UCLES 2014 0620/11/M/J/14

11
28 The table shows properties of four metals.
Which metal is the most suitable for aircraft construction?
resistance to
density strength
corrosion
A high high low

B high low low
C low high high
D low low high
29 The diagram shows a blast furnace.
In which part is iron ore changed to iron?
C
D
30 The diagram shows some uses of water in the home.
1 2 3
For which uses is it important for the water to have been treated?
A 1 only B 2 only C 3 only D 1, 2 and 3

12
31 Four steel paper clips are treated as described before being placed in a beaker of water.
Which paper clip rusts most quickly?
A coated with grease

B dipped in paint and allowed to dry
C electroplated with zinc
D washed with soap and rinsed
32 Which compound contains two of the three essential elements needed for a complete fertiliser?
A ammonium chloride
B ammonium nitrate
C ammonium phosphate
D ammonium sulfate
33 When compound X is heated, it changes colour from green to black. Compound Y is formed and
a gas is given off which turns limewater milky.
What are X and Y?
X Y
A calcium carbonate calcium oxide

B copper carbonate carbon
C copper carbonate copper oxide
D copper sulfate copper oxide
34 Acid rain is formed when sulfur dioxide and oxides of nitrogen dissolve in rain water.
Which problem is not caused by acid rain?
A breathing difficulties
B dying trees
C erosion of statues
D lowered pH of lakes
© UCLES 2014 0620/11/M/J/14

13
35 Which pollutant gas is produced by the decomposition of vegetation?
A carbon monoxide
B methane
C nitrogen oxide
D sulfur dioxide
36 Which type of compound is shown?
H H H
H C C C OH
H H H
A alcohol
B alkane
C alkene
D carboxylic acid
37 The table shows the composition of four different types of petroleum (crude oil).
Arabian Heavy Arabian Light Iranian Heavy North Sea

fraction
/% /% /% /%
gasoline 18 21 21 23
kerosene 11.5 13 13 15
diesel oil 18 20 20 24
fuel oil 52.5 46 46 38
Which type of petroleum is best for the motor vehicle industry?
A Arabian Heavy
B Arabian Light
C Iranian Heavy
D North Sea

14
38 Alkenes are manufactured by cracking hydrocarbons obtained from petroleum.
alkane X obtained cracking

alkene Y
from petroleum
Which row describes the process of cracking?
size of X size of Y catalyst temperature

molecules molecules required required
A large small no low

B large small yes high
C small large no low
D small large yes high
39 X, Y and Z are three hydrocarbons.
X CH2=CH2 Y CH3–CH=CH2 Z CH3–CH2–CH=CH2
What do compounds X, Y and Z have in common?
1 They are all alkenes.

2 They are all part of the same homologous series.
3 They all have the same boiling point.
40 Which statements about ethanol are correct?
1 It can be made by fermentation.

2 It is an unsaturated compound.
3 It burns in air and can be used as a fuel.
© UCLES 2014 0620/11/M/J/14

15
BLANK PAGE
© UCLES 2014 0620/11/M/J/14

© UCLES 2014
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/11/M/J/14
Indium Iodine
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY
Question Question
Key Key
Number Number
1 D 21 D
2 A 22 A
3 C 23 C
4 A 24 D
5 D 25 C
6 C 26 C
7 D 27 C
8 B 28 C
9 D 29 B
10 C 30 A
11 C 31 D
12 B 32 C
13 A 33 C
14 B 34 A
15 A 35 B
16 B 36 A
17 B 37 D
18 B 38 B
19 D 39 B
20 B 40 C

*1339612500*
CHEMISTRY 0620/21
1 hour 15 minutes

IB14 06_0620_21/2RP
2
1 (a) Choose from the list of substances below to answer the following questions.
calcium oxide
carbon dioxide
carbon monoxide
copper
hydrogen
magnesium
methane
oxygen
water
Each substance may be used once, more than once or not at all.
Which substance:
(i) releases hydrogen when it reacts with steam,
....................................................................................................................................... [1]
(ii) is produced at the cathode when concentrated aqueous sodium chloride is electrolysed,
....................................................................................................................................... [1]
(iii) is a product of the incomplete combustion of carbon,
....................................................................................................................................... [1]
(iv) is used in electrical wiring,
....................................................................................................................................... [1]
(v) is manufactured by heating limestone?
....................................................................................................................................... [1]
(b) Complete the following sentences about the Periodic Table of elements using words from the
list below.
argon colour density sodium
one similarity trend seven
Chlorine, bromine and iodine are elements in Group ......................... of the Periodic Table.
These elements show a ......................... in ......................... down the group.
They all react rapidly with ......................... to form ionic compounds. [4]
[Total: 9]
© UCLES 2014 0620/21/M/J/14

3
2 In 1904, J. J. Thomson suggested a model of the atom. He called this the ‘plum pudding’ model.
This model of an atom, containing 14 electrons, is shown below.
sphere of positive charge

which is spread out
electrons
(a) Describe how Thomson’s model of the atom differs from our present ideas of the structure of
an atom.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(b) Lithium has two naturally-occurring isotopes. These can be written as:
6 7
3 Li and 3 Li
(i) Describe the difference between these isotopes.
....................................................................................................................................... [1]
(ii) Isotopes can be radioactive or non-radioactive.

State one industrial use of radioactive isotopes.
....................................................................................................................................... [1]
(c) Lithium is in Group I of the Periodic Table.

The table shows some properties of the Group I elements.
metal melting point / °C atomic radius / nm

lithium 0.157
sodium 98 0.191
potassium 63
rubidium 39 0.250
caesium 29 0.272
Deduce:
the melting point of lithium, ........................................................................... °C
the atomic radius of potassium .................................................................... nm [2]

4
(d) Lithium reacts with water. An alkaline solution and a colourless gas are formed.
lithium + water → .......................... .......................... + ..........................

[2]
(ii) What is the most likely pH of the alkaline solution?

[1]
(e) Draw the electronic structure of a potassium atom.
[2]
[Total: 12]
© UCLES 2014 0620/21/M/J/14

5
3 The table shows some fractions obtained from the distillation of petroleum.
number of boiling point of

fraction
carbon atoms the fraction / °C
refinery gas 1–4 under 40

gasoline 5 – 10 40 – 160
kerosene 10 – 16 160 – 250
diesel 16 – 20 250 – 300
fuel oil 20 – 30 300 – 350
(a) What is the relationship between the number of carbon atoms and the boiling points of the
fractions?
.............................................................................................................................................. [1]
(b) State the names of two petroleum fractions not given in the table.
................................................................... and ................................................................... [2]
(c) Two of the compounds present in refinery gas are methane and ethane.
(i) Draw the structure of ethane. Show all atoms and bonds.
[1]
(ii) Complete the dot and cross diagram of methane to show all the electrons.
H C H
[2]

6
(d) Refinery gas also contains propane.

Propane can be cracked in the presence of a catalyst to form hydrogen.
(i) Complete the symbol equation for this reaction.
C3H8 → ............... + H2
[1]
(ii) A catalyst is one condition needed to crack an alkane.
State one other condition needed to crack an alkane.
....................................................................................................................................... [1]
[Total: 8]
© UCLES 2014 0620/21/M/J/14

7
4 The diagram shows the changes of state when tin vapour is cooled slowly to room temperature.
tin condensation liquid solidification solid

vapour tin (freezing) tin
(a) Explain what happens to the arrangement and motion of the atoms during these changes.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
(b) Tin is a metal in Group IV of the Periodic Table.

How many electrons does tin have in its outer shell?
.............................................................................................................................................. [1]
(c) State one physical property of tin.
.............................................................................................................................................. [1]
(d) The table below describes the reaction of some metals with dilute hydrochloric acid.
bubbles of gas produced and temperature

iron
of the mixture rises slowly
many bubbles of gas produced rapidly and
magnesium
temperature of the mixture rises rapidly
no bubbles of gas given off and no
silver
temperature change
a few bubbles of gas given off slowly and
tin
temperature of the mixture rises very slowly
Put these metals in order of their reactivity.
[2]

8
(e) Tin is extracted by heating tin(IV) oxide with carbon.
SnO2 + .......C → Sn + .......CO

[2]
(ii) State one adverse effect of carbon monoxide on health.
....................................................................................................................................... [1]
[Total: 11]
© UCLES 2014 0620/21/M/J/14

9
5 The diagram shows a blast furnace for extracting iron.
mixture of
iron ore
and coke
(a) On the diagram above, write:
● the letter A to show where the air blast enters the furnace,
● the letter W to show where the waste gases exit the furnace.
[2]
(b) Which one of the following is an ore of iron?

calcite fluorite hematite halite

[1]
(c) In the furnace, the coke burns to form carbon dioxide. This reaction is exothermic.
(i) What is meant by the term exothermic ?
....................................................................................................................................... [1]
(ii) Describe a test for carbon dioxide.
test ......................................................................................................................................
result ............................................................................................................................. [2]
(d) In the blast furnace, carbon dioxide reacts with more coke to form carbon monoxide.
The carbon monoxide reduces iron(III) oxide to iron.
Fe2O3 + 3CO → 2Fe + 3CO2
How does this equation show that iron(III) oxide is being reduced?
.............................................................................................................................................. [1]
[Total: 7]

10
6 The structure of ethanol is shown below.
H H
H C C O H
H H
(a) On the structure above, put a ring around the alcohol functional group. [1]
(b) Ethanol can be made by fermentation.
(i) Complete the word equation for fermentation.
............................ → ethanol + ............................ ............................

[2]
(ii) What type of catalysts are used in fermentation?

acids carbonates enzymes metals

[1]
(c) Ethanol can also be made by hydration.

............................ + H2O → C2H5OH

[1]
(d) The diagram below shows how the rate of fermentation changes with temperature.
rate
0 10 20 30 40 50 60
temperature / °C
Describe how the rate of fermentation changes with temperature.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
© UCLES 2014 0620/21/M/J/14

11
(e) The table shows some properties of different alcohols.
melting point boiling point density

alcohol formula
/ °C / °C in g / cm3
methanol CH4O – 94 65
ethanol C 2 H 6O –117 79 0.789
propanol C 3 H 8O –126 98 0.804
butanol C4H10O – 89 117 0.810
pentanol C5H12O – 79 138 0.815
(i) Describe how density changes with the number of carbon atoms in the alcohol.
....................................................................................................................................... [1]
(ii) Which one of these alcohols has the lowest melting point?
....................................................................................................................................... [1]
(iii) Is pentanol a solid, liquid or gas at room temperature?

.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [1]
[Total: 10]

12
7 A student used chromatography to separate the dyes in the blue ink from a ball-point pen.
She used the equipment shown in the diagrams below.
chromatography paper solvent large watchglass chromatography tank
(a) Complete the diagram below to show how she set up the apparatus.
[3]
(b) Describe how chromatography could be used by the student to separate the dyes.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(c) The student used water as a solvent. Suggest a different solvent that she could use.
.............................................................................................................................................. [1]
© UCLES 2014 0620/21/M/J/14

13
(d) The diagram below shows the results of the chromatography using the blue ink, B, and several
pure dyes, W, X, Y and Z.
B W X Y Z
(i) Which of the dyes, W, X, Y and Z, were in the blue ink?
....................................................................................................................................... [1]
(ii) How many dyes in the ink had been separated by this chromatography?
....................................................................................................................................... [1]
(e) The diagram shows the ball-point pen used in the experiment.
poly(ethene) cap
alloy tip
ink
(i) The cap of the pen is made of poly(ethene).

Describe the formation of poly(ethene) from ethene. In your answer, include the words:
● monomer,
● polymer.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) The tip of the pen is made from an alloy.

What is meant by the term alloy ?
.............................................................................................................................................
....................................................................................................................................... [1]

14
(f) The table shows some properties of four alloys.
thermal
strength density
alloy conductivity
/ GPa in g / cm3
in W / m / K
low strength steel 250 7.70 60

high strength steel 300 7.90 56
low strength aluminium 70 2.72 170
high strength aluminium 220 2.80 100
(i) How does the strength of the steel and aluminium alloys vary with their thermal
conductivity?
....................................................................................................................................... [1]
(ii) Which one of these alloys is the best one to use to make the body of an aircraft?
Give two reasons for your answer.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
[Total: 16]
© UCLES 2014 0620/21/M/J/14

15
8 Zinc can be extracted from zinc sulfide ore in three steps.
(a) In the first step, zinc sulfide is heated in air to produce zinc oxide.
2ZnS + ....O2 → 2ZnO + .....SO2

[2]
(ii) The product sulfur dioxide, SO2, is harmful to the environment.

Explain why it is harmful to the environment and state one effect it has on buildings.
.............................................................................................................................................
....................................................................................................................................... [2]
(b) In the second step, zinc oxide reacts with sulfuric acid to form zinc sulfate.
zinc oxide + sulfuric acid → zinc sulfate + water
Zinc sulfate is soluble in water.

Some insoluble impurities in the zinc oxide do not react with the sulfuric acid.
Suggest how these insoluble impurities are removed from the zinc sulfate solution.
.............................................................................................................................................. [1]
(c) In the third step, zinc is extracted from zinc sulfate by electrolysis using the cell shown below.
+ –
lead rod aluminium rod
aqueous zinc sulfate
(i) Which word best describes the aluminium rod?

anion anode cathode cation electrolyte product

[1]

16
(ii) Suggest which statement about this electrolysis is completely correct.

Tick one box.
Zinc is formed at the positive electrode and

hydrogen at the negative electrode.
Zinc is formed at the positive electrode and

oxygen at the negative electrode.
Zinc is formed at the negative electrode and

hydrogen at the positive electrode.
Zinc is formed at the negative electrode and

oxygen at the positive electrode.
[1]
[Total: 7]
© UCLES 2014 0620/21/M/J/14

17
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© UCLES 2014 0620/21/M/J/14

18
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© UCLES 2014 0620/21/M/J/14

19
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© UCLES 2014 0620/21/M/J/14

© UCLES 2014
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
20
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/21/M/J/14
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY
1 (a) (i) magnesium / Mg [1]

allow: methane / CH4
(ii) hydrogen / H2 [1]
(iii) carbon monoxide / CO [1]
(iv) copper / Cu [1]
(v) calcium oxide / CaO;

allow: carbon dioxide / CO2 [1]
(b) 1 mark for each correct word:

seven;
trend;
density / colour;
sodium. [4]
[Total: 9]
2 (a) any three points (1 mark each) e.g. [3]

• electrons random / electrons not in shells ORA e.g. electrons in shells
• electrons are negatively charged ORA
• positive charge spread out / diffuse charge ORA e.g. protons have + charge
• no nucleus ORA e.g. nucleus present
• no protons / no neutrons / no nucleons / no nuclear particles ORA
(b) (i) different number of neutrons / different mass number / different nucleon
number [1]
(ii) any suitable use e.g. [1]

• energy production / nuclear power / power stations
• measuring thickness of paper
• finding cracks in pipelines / pipes
• smoke alarms
(c) melting point any value between 120–200 (°C) [1]

atomic radius any value between 0.220 and 0.240 (nm) [1]
(d) (i) lithium hydroxide; [1]

hydrogen [1]
(ii) pH 13 [1]
(e) 1 electron in outer shell; [1]

inner shells correct i.e. 2, 8, 8 [1]
[Total: 12]

3 (a) the more (carbon) atoms, the higher the boiling point [1]

• naphtha
• lubricating (oil) / lubricant
• bitumen
(c) (i) correct structure of ethane showing all atoms and bonds; [1]
(ii) 2 inner shell electrons for C; [1]

4 bonding pairs of electrons representing each C–H bond; [1]
(d) (i) C3H6 [1]
(ii) heat / high temperature; [1]

ALLOW: quoted temperature values between 300-800 °C
ALLOW: high pressure
[Total: 8]
4 (a) any four from: [4]

• atoms in gas irregularly arranged / randomly arranged / far apart / all over the
place
• atoms in gas moving very fast / free to move / bouncing around
• atoms slow down during condensation / move less than before
• atoms become less randomly arranged / less irregularly arranged during
condensation / atoms get closer together in condensation
• atoms in liquid are irregularly arranged / close together / touching
• atoms in liquids slide over each other / atoms in liquids move slowly
• atoms slow down (further) during freezing
• atoms become more regularly arranged during freezing
• atoms in solid only vibrate
• atoms in solid are regularly arranged / touching / close to each other
(b) 4 / four [1]
(c) Any physical property e.g. [1]

malleable / ductile / conduct heat / conduct electricity / conducts (unqualified) /
silvery / shiny / sonorous
ALLOW: high melting point / high boiling point / solid at room temperature
IGNORE: reference to density / hardness
(d) silver < tin < iron < magnesium [2]

1 mark if 1 pair inverted / magnesium > iron > tin > silver

(e) (i) 2 (CO); [1]

2 (C) dependent on 2CO being correct; [1]
(ii) poisonous / toxic; [1]
[Total: 11]
5 (a) A shown correctly (on either left or right top pipes at base of furnace) [1]
W shown correctly on one of the two pipes at the top [1]
(b) hematite [1]
(c) (i) heat given off / energy given out [1]
(ii) limewater; [1]

turns milky / turns cloudy / white precipitate; [1]
note: second mark dependent on first being correct
(d) iron oxide is losing oxygen / CO is gaining oxygen [1]
[Total: 7]
6 (a) ring around the OH group only [1]
(b) (i) (on left) sugar / glucose / any other suitable sugar; [1]
(on right) carbon dioxide; [1]
(ii) enzymes; [1]
(c) C2H4 [1]
(d) increases up to a maximum / increases up to given figure between 35–40 °C /

rises to a peak; [1]
(e) (i) (density) increases as the number of carbon atoms increases; [1]
allow: decreases as the number of C atoms gets lower
(ii) propanol; [1]
(iii) liquid because its melting point is below room temperature and boiling point
is above room temperature / becomes liquid at –79 °C (and does not become
a) gas until 138 °C / room temperature is between the boiling point and
melting point (room temperatures for last answer can be between 5 and
40 °C) [1]
[Total: 10]

7 (a) square / rectangular sheet of paper in chromatography tank; [1]

note: the sheet should not touch the sides of the beaker
solvent at bottom of tank with paper dipping into it; [1]

note: solvent does not have to be labelled / paper can just touch the surface
But there should be no gap between the solvent and the paper
watchglass over the tank (this can just be shown as a line); [1]
(b) place spot of ink / dye on the paper; [1]

note: answer must imply a spot or drop (not just ink put on paper)
above the solvent level; [1]
let the solvent run up the paper / solvent moves the dyes up the paper / some
idea that solvent is needed for the movement of the spots; [1]
(c) any suitable solvent e.g. ethanol / butanol / ester / alcohol [1]
(d) (i) W, X and Y; [1]
(ii) 4 / four; [1]
(e) (i) idea that ethene is the monomer / idea that monomers are the simple (or
basic) units which add together; [1]
idea that poly(ethene) is the polymer / idea that the polymer is formed by
adding ethene units / simple units combine to form polymer / idea that
polymer is a very long (hydrocarbon) chain; [1]
note: (ethene) monomers join to make a polymer = 2 marks
(ii) mixture of metals / mixture of metal + non metal; [1]
(f) (i) increasing strength decreases (thermal) conductivity / the lower the
conductivity the higher the strength; [1]
(ii) high strength aluminium; [1]
has high strength / it is strong / aircraft body need to be strong; [1]
it has low density / it is light(weight) / aircraft body needs to be light(weight) [1]
[Total: 16]
8 (a) (i) 2 (SO2); [1]
3 (O2); [1]

(ii) causes acid rain / it is acidic / it acidifies (something); [1]
erodes (limestone) buildings / erodes mortar / corrodes metalwork / corrodes

bridges / erodes named carbonate rock [1]
(b) filtration / filtered [1]
(c) (i) cathode; [1]
(ii) last / 4th box ticked (zinc at negative electrode and O2 at positive electrode); [1]
[Total: 7]

*3226538232*
CHEMISTRY 0620/31
1 hour 15 minutes

IB14 06_0620_31/2RP
2
1 The table below gives the composition of six particles which are either atoms or ions.
particle number of protons number of neutrons number of electrons

A 33 40 33
B 19 20 18
C 34 45 36
D 33 42 33
E 13 14 13
F 24 28 21
(a) Which particles are atoms? Explain your choice.
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) Which particle is a negative ion and why has this particle got a negative charge?
....................................................................................................................................................
.............................................................................................................................................. [2]
(c) Which particles are positive ions?
.............................................................................................................................................. [1]
(d) Explain why particle A and particle D are isotopes.
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 7]
© UCLES 2014 0620/31/M/J/14

3
2 (a) Water is needed for industry and in the home.
(i) Rain water is collected in reservoirs. How is it treated before entering the water supply?
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) State two industrial uses of water.
.............................................................................................................................................
....................................................................................................................................... [2]
(iii) State two uses of water in the home.
.............................................................................................................................................
....................................................................................................................................... [1]
(b) In many regions, drinking water is obtained by the distillation of sea-water. Explain how
distillation separates the water from sea-water.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 7]

4
3 (a) Different gases diffuse at different speeds.
(i) What is meant by the term diffusion?
.............................................................................................................................................
....................................................................................................................................... [1]
(ii) What property of a gas molecule affects the speed at which it diffuses?
....................................................................................................................................... [1]
(b) Helium is a gas used to fill balloons. It is present in the air in very small quantities. Diffusion can
be used to separate it from the air.
Air at 1000 °C is on one side of a porous barrier. The air which passes through the barrier has
a larger amount of helium in it.
(i) Why does the air on the other side of the barrier contain more helium?
....................................................................................................................................... [1]
(ii) Why is it an advantage to have the air at a high temperature?
.............................................................................................................................................
....................................................................................................................................... [1]
(c) Most helium is obtained from natural gas found in the USA. Natural gas contains methane and
7% helium. One possible way to obtain the helium would be to burn the methane.
(i) Write an equation for the complete combustion of methane.
....................................................................................................................................... [1]
(ii) Suggest why this would not be a suitable method to obtain the helium.
.............................................................................................................................................
....................................................................................................................................... [1]
(iii) Suggest another method, other than diffusion, by which helium could be separated from
the mixture of gases in natural gas.
....................................................................................................................................... [1]
[Total: 7]
© UCLES 2014 0620/31/M/J/14

5
4 In the Periodic Table, the elements are arranged in columns called Groups and in rows called
Periods.
(a) (i) Complete the table for some of the elements in Period 3.
group number I II III IV V VI VII
symbol Na Mg Al Si P S Cl
number of
valency electrons
valency
[2]
(ii) What is the relationship between the group number and the number of valency electrons?
.............................................................................................................................................
....................................................................................................................................... [1]
(iii) Explain the relationship between the number of valency electrons and the valency
for the elements Na to Al,
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
for the elements P to Cl.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
[4]
(b) Across a period, the elements change from metallic to non-metallic.
(i) Describe how the type of oxide changes across this period.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Describe how the type of bonding in the chlorides formed by these elements changes
across this period.
.............................................................................................................................................
....................................................................................................................................... [2]
[Total: 11]

6
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© UCLES 2014 0620/31/M/J/14

7
5 Zinc is obtained from the ore, zinc blende, ZnS.
(a) Describe the extraction of zinc from its ore, zinc blende. Include at least one balanced equation
in your description.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]
(b) State two major uses of zinc.
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 7]

8
6 Hydrogen peroxide decomposes to form water and oxygen. This reaction is catalysed by
manganese(IV) oxide.
2H2O2(aq) → 2H2O(l) + O2(g)
The rate of this reaction can be investigated using the following apparatus.
oxygen gas
aqueous hydrogen peroxide

and manganese(IV) oxide
40 cm3 of aqueous hydrogen peroxide was put in the flask and 0.1 g of small lumps of manganese(IV)
oxide was added. The volume of oxygen collected was measured every 30 seconds. The results
were plotted to give the graph shown below.
volume of
oxygen
0
0 t t2 t3
1
time
(a) (i) How do the rates at times t1, t2 and t3 differ?
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Explain the trend in reaction rate that you described in (a)(i).
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
© UCLES 2014 0620/31/M/J/14

9
(b) The experiment was repeated using 0.1 g of finely powdered manganese(IV) oxide. All the
other variables were kept the same.
(i) On the axes opposite, sketch the graph that would be expected. [2]
(ii) Explain the shape of this graph. ..........................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(c) Describe how you could show that the catalyst, manganese(IV) oxide, was not used up in the
reaction. Manganese(IV) oxide is insoluble in water.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
(d) In the first experiment, the maximum volume of oxygen produced was 96 cm3 measured at
r.t.p. Calculate the concentration of the aqueous hydrogen peroxide in mol / dm3.
2H2O2(aq) → 2H2O(l) + O2(g)
number of moles of O2 formed = .......................................................................................... [1]
number of moles of H2O2 in 40 cm3 of solution = ................................................................. [1]
concentration of the aqueous hydrogen peroxide in mol / dm3 = ................................................
.......................................... [1]
[Total: 15]

10
7 One way of establishing a reactivity series is by displacement reactions.
(a) A series of experiments was carried out using the metals lead, magnesium, zinc and silver.
Each metal was added in turn to aqueous solutions of the metal nitrates.
The order of reactivity was found to be:
magnesium most reactive

zinc
lead
↓
silver least reactive
(i) Complete the table.
= reacts
= does not react
metal
aqueous lead magnesium zinc silver
solution Pb Mg Zn Ag
lead(II)

nitrate
magnesium
nitrate
zinc
nitrate
silver
nitrate
[3]
(ii) Displacement reactions are redox reactions.

On the following equation, draw a ring around the reducing agent and an arrow to show
the change which is oxidation.
Zn + Pb2+ → Zn2+ + Pb
[2]
(iii) Complete the following ionic equation.
Zn + 2Ag+ → ....... + .......

[1]
© UCLES 2014 0620/31/M/J/14

11
(b) Another way of determining the order of reactivity of metals is by measuring the voltage and
polarity of simple cells. The polarity of a cell is shown by which metal is the positive electrode
and which metal is the negative electrode. An example of a simple cell is shown below.
voltmeter
V
+ –
lead electrode zinc electrode
electrolyte of
dilute acid
(i) Mark on the above diagram the direction of the electron flow. [1]
(ii) Explain, in terms of electron transfer, why the more reactive metal is always the negative
electrode.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(iii) The following table gives the polarity of cells using the metals zinc, lead, copper and
manganese.
cell electrode 1 polarity electrode 2 polarity

A zinc – lead +
B manganese – lead +
C copper + lead –
What information about the order of reactivity of these four metals can be deduced from
the table?
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(iv) What additional information is needed to establish the order of reactivity of these four
metals using cells?
....................................................................................................................................... [1]
[Total: 12]

12
8 Polymers are made by the polymerisation of simple molecules called monomers.
(a) (i) The structural formula of a polymer is given below.
CH CH
CH3 CH3 n
This polymer is made by addition polymerisation. Draw the structural formula of its
monomer.
[1]
(ii) The two monomers shown below form a nylon which is a condensation polymer.
H 2N NH2
HOOC COOH
Draw its structural formula showing one repeat unit of the polymer.
[3]
(iii) Name the natural macromolecule which contains the same linkage as nylon.
....................................................................................................................................... [1]
(iv) Explain the difference between addition polymerisation and condensation polymerisation.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
© UCLES 2014 0620/31/M/J/14

13
(b) Many polymers are non-biodegradable.
(i) Explain the term non-biodegradable.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) State three problems caused by the disposal of non-biodegradable polymers.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(c) Storage tanks for cold water are now made from polymers because they are cheaper than
metal tanks. Suggest two other advantages of making cold water tanks from polymers.
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 14]

14
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© UCLES 2014 0620/31/M/J/14

15
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© UCLES 2014 0620/31/M/J/14

© UCLES 2014
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/31/M/J/14
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY
1 (a) A, D, E (1)
same number of protons and electrons / electrically neutral (1) [2]
(b) C (1)
more electrons than protons / 36e– and 34p+ / it has gained electrons (1) [2]
(c) B, F (1) [1]
(d) they have same number of protons (1)
different number of neutrons / neutron number (1) [2]
[Total: 7]
2 (a) (i) filtration (1)
chlorination (1) [2]
(ii) Any two from: [2]

• manufacture of ethanol
• used in the manufacture of sulfuric acid or in the Contact process
• manufacture of hydrogen or ammonia or for the Haber process
(iii) Any two from: [2]

• cooking
• washing or laundry
• drinking
• toilets
• watering plants
• (domestic) heating
(b) boiling or turning to steam (1)
then condensing / condensation (1) [2]
[Total: 7]
3 (a) (i) (particles) spread to fill total available volume / move from high concentration
to low concentration / moves down a concentration gradient (1) [1]
(ii) mass or Mr (1) [1]
(b) (i) helium atoms / molecules are lighter than molecules in air or N2 and O2
or helium is less dense than air or N2 and O2.
or helium diffuses (through the porous barrier) faster than air or N2 and
O2. (1) [1]

(ii) faster rate of diffusion / molecules move faster (at high temperatures). (1) [1]
(c) (i) CH4 + 2O2 → CO2 + 2H2O (1) [1]
(ii) would get a mixture of helium and carbon dioxide

or would get a mixture of gases
or waste of methane / natural gas / fossil fuel (1) [1]
(iii) fractional distillation (1) [1]
[Total: 7]
4 (a) (i)
Group I II III IV V VI VII
number
symbol Na Mg Al Si P S Cl
number of 1 2 3 4 5 6 7
valency
electrons
valency 1 2 3 4 3 2 1
(1) for each line [2]
(ii) number of valency electrons = the group number (1) [1]
(iii) for Na to Al
the valency is the same as the number of valency (outer) electrons (1)
(because) this is the number of electrons lost (for full energy level) (1)
for P to Cl
the valency is 8 – [number of valency (outer) electrons]
or valency + valency electrons = 8 (1)
(because) this is number of electrons needed (or to be gained) (for full

energy level) (1)
(b) (i) Assume change is from L to R unless clearly stated:

basic to amphoteric to acidic (2) [2]
(ii) ionic (metal) chlorides on the left (1)

covalent (non-metal) chlorides on the right (1) [2]
[Total: 11]

5 (a) M1: (zinc sulfide) heated / roasted / burnt in air (1)
M2: zinc oxide formed (1)
M3: zinc oxide reduced (1)
M4: (by adding) coke or carbon (1)
M5: Balanced equation (any one of) (1) [5]
2ZnS + 3O2 → 2ZnO + 2SO2

2ZnO + C → 2Zn + CO2
ZnO + C → Zn + CO
ZnO + CO → Zn + CO2
• (making) brass or alloys (1)

• galvanising (1)
• sacrificial protection (1)
• batteries (1)
[Total: 7]
6 (a) (i) rate at t2 less than at t1 or the rate decreases (1)
rate at t3 zero / reaction stopped (1) [2]
(ii) rate at t2 less than at t1 because concentration of hydrogen peroxide is less

at t2 or concentration of hydrogen peroxide is decreasing. (1)
(rate at t3 zero / reaction stopped because) hydrogen peroxide is used up (1) [2]
(b) (i) steeper and must come from the origin (1)
final volumes the same (1) [2]
(ii) Any two from: [2]

steeper curve because of a faster rate
faster rate because of increased surface area
same amount / volume / mass / no of mol of hydrogen peroxide
ecf for M1 for a shallower curve because of slower rate.

(c) filter (and rinse / wash) (1)
dry manganese (IV) oxide (1)
weigh / measure mass manganese(IV) oxide after reaction (1)
the mass should be 0.1 g or unchanged. (1) [4]
(d) number of moles of O2 formed = 0.096 / 24 = 0.004 (1)

number of moles of H2O2 in 40 cm3 of solution = 0.004 × 2 = 0.008 (1)
concentration of the hydrogen peroxide in mol / dm3 = 0.008 / 0.04 = 0.2 (1) [3]
[Total:15]
7 (a) (i)
aqueous lead magnesium zinc silver
solution Pb Mg Zn Ag
lead (II)

nitrate
magnesium
X
nitrate
zinc

nitrate
silver(I)

nitrate
each horizontal line correct (1) [3]
(ii) Zn (1)
An arrow from Zn to Zn2+ (1) [2]
(iii) Zn + 2Ag+ → Zn2+ + 2Ag (1) [1]
(b) (i) correct direction from zinc to lead (1) [1]
(ii) metals react by losing electrons (1)
the more reactive metal / zinc will lose electrons more readily (making the
electrode negatively charged). (1) [2]

(iii) manganese and zinc are more reactive than lead (and / or copper) (1)
lead is more reactive than copper (1) [2]
(iv) the polarity of a Mn / Zn (cell)

or the voltages of Zn / Pb and Mn / Pb (cells) (1) [1]
[Total: 12]
8 (a) (i) CH3–CH=CH–CH3 (1) [1]
(ii) one correct amide linkage between two rectangles (1)
correct sequencing of a second amide link and monomers (1)
two correct amide links and rest of structure correct (including additional
monomers if seen) and correct continuation bonds (1) [3]
(iii) protein or polypeptide or named protein (1) [1]
(iv) addition: only the polymer or one product is formed (1)
condensation: the polymer and a small molecule / water / HCl is formed (1) [2]
(b) (i) does not break down or rot or decompose (1)
by microbes or fungi or bacteria or by living organisms (1) [2]
(ii) Any three from: [3]

visual pollution (1)
(shortage of) landfill sites (1)
danger to wildlife / animals (including at sea) (1)
toxic gases when burnt or greenhouse gases produced when burned (1)
(c) Any two from: [2]

resistant to corrosion / unreactive to water / more durable (1)
lighter / less dense (1)
easier to manufacture / can be moulded (1)
good insulator / keeps the water cold (1)

[Total: 14]

CHEMISTRY 0620/51
*6529401984*
where relevant.
by phone: +44 1223 553554,
by fax: +44 1223 553558,
IB14 06_0620_51CI/4RP
2
For Question 1
(d) 100 cm3 of aqueous hydrochloric acid of concentration 0.2 mol / dm3, labelled hydrochloric
acid
[H] (e) 50 cm3 of an aqueous solution which is a mixture of sodium hydroxide, NaOH, of concentration
0.05 mol / dm3, and sodium carbonate, Na2CO3, of concentration 0.05 mol / dm3 labelled
solution R
Solution R can be made up by dissolving 2 g of sodium hydroxide and 5.3 g of anhydrous

sodium carbonate in distilled water and making the solution up to 1 dm3
(f) access to water and distilled water
[N] [H] (g) phenolphthalein indicator
[H] (h) methyl orange indicator
(i) one white tile
(j) one test-tube
(k) teat pipette
(l) one funnel for filling burette
© UCLES 2014 0620/51/CI/M/J/14

3
For Question 2
[N] [H] (a) a stoppered test-tube containing about 1 g of manganese(II) sulfate crystals, MnSO4.1H2O,
labelled solid U
(b) rack of test-tubes
(c) access to water and distilled water
(d) splints
(e) stopper to fit test-tubes
[C] (f) aqueous sodium hydroxide of concentration 1.0 mol / dm3
(g) aqueous ammonia of concentration 1.0 mol / dm3
(h) aqueous barium nitrate of suitable concentration to give a positive sulfate test
[C] (i) aqueous nitric acid of concentration 1.0 mol / dm3
[N] [H] (j) aqueous silver nitrate of suitable concentration to give a positive halide test
(k) hydrogen peroxide solution of concentration 10 volumes
(l) spatula
(m) one 10 cm3 measuring cylinder
(n) a Bunsen burner and matches
(o) teat pipettes
© UCLES 2014 0620/51/CI/M/J/14 [Turn over

4
© UCLES 2014 0620/51/CI/M/J/14

5

6
© UCLES 2014 0620/51/CI/M/J/14

7
JUNE 2014
penalised.
© UCLES 2014 0620/51/CI/M/J/14

[Turn over
8
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
© UCLES 2014 0620/51/CI/M/J/14

*5760352473*
CHEMISTRY 0620/51
1 hour 15 minutes

Total
IB14 06_0620_51/4RP
2
1 You are going to investigate what happens when dilute hydrochloric acid reacts with an
aqueous solution R, containing two different substances S and T.
Instructions
(a) Experiment 1
Using a measuring cylinder, pour 25 cm3 of solution R into the conical flask. Add five drops of
the phenolphthalein indicator to the flask.
Fill the burette with hydrochloric acid to the 0.0 cm3 mark. Using the burette, add hydrochloric
acid to solution R and shake the flask. Continue to add hydrochloric acid to the flask until the
colour just disappears.
Record the volume of hydrochloric acid added when the indicator changes colour.
Keep the mixture in the flask for Experiment 2.
burette readings
final volume / cm3
difference / cm3
[3]
(b) Experiment 2
Add four drops of methyl orange indicator to the mixture in the flask from Experiment 1.
Check that the burette reading is the same as your final reading in Experiment 1. This is the
initial volume reading for Experiment 2.
Using the burette, add hydrochloric acid to the mixture in the flask and shake the mixture.
Record the volume of hydrochloric acid added when the indicator just changes colour.
burette readings
final volume / cm3
difference / cm3
[4]
(c) Experiment 3
Pour about 5 cm3 of solution R into a test-tube. Using a teat pipette, add hydrochloric acid to
the solution. Note any observations.
.............................................................................................................................................. [1]
© UCLES 2014 0620/51/M/J/14

3
(d) (i) When phenolphthalein indicator was used in Experiment 1 the colour changed
from ............................................................ to ............................................................. [2]
(ii) What was the colour of the indicator at the end-point in Experiment 2?
....................................................................................................................................... [1]
(e) (i) What type of substances are S and T?
....................................................................................................................................... [1]
(ii) What conclusion can you draw from Experiment 3?
....................................................................................................................................... [1]
(f) The volume of hydrochloric acid added in Experiment 1 reacted with all of substance S and half
of substance T.
The volume of hydrochloric acid in Experiment 2 reacted with half of substance T.
(i) Work out the volume of hydrochloric acid which reacted with substance S.
....................................................................................................................................... [2]
(ii) Work out the volume of hydrochloric acid which reacted with substance T.
....................................................................................................................................... [1]
(iii) Compare the volumes of hydrochloric acid which reacted with substances S and T.
.............................................................................................................................................
....................................................................................................................................... [1]
(g) (i) Predict the volume of hydrochloric acid which would be added in Experiments 1 and 2 if
the experiments were repeated using 100 cm3 of solution R. Explain your answer.
Experiment 1 ......................................................................................................................
Experiment 2 ......................................................................................................................
Explanation ................................................................................................................... [3]
(ii) Suggest a practical problem that would occur when carrying out these repeat experiments
and how you could solve this problem.
.............................................................................................................................................
....................................................................................................................................... [2]
[Total: 22]

4
2 You are provided with solid U, which is a metal salt.

Carry out the following tests on U, recording all of your observations in the table.
tests observations
tests on solid U
(a) Describe the appearance of solid U. ................................................................ [2]
(b) Place half of solid U in a test-tube. ......................................................................

Heat the test-tube gently at first and then
more strongly. ................................................................ [2]
(c) Add the rest of solid U to about 8 cm3 of

distilled water in a test-tube.
Stopper the test-tube and shake the
contents until dissolved.
Divide the solution into four equal portions
in separate test-tubes and carry out the
following tests.
Add several drops of aqueous

sodium hydroxide to the first portion of the
solution and shake the test-tube. ......................................................................
Then add about 1 cm3 of hydrogen peroxide

solution to the mixture. ......................................................................
Test the gas given off. ................................................................ [5]
(d) Add excess aqueous ammonia to the

second portion of the solution. ................................................................ [1]
(e) Add about 1 cm3 of dilute nitric acid to the

third portion of the solution followed by
about 1 cm3 of barium nitrate solution. ................................................................ [2]
(f) Add about 1 cm3 of dilute nitric acid to the

fourth portion of the solution followed by
about 1 cm3 of silver nitrate solution. ................................................................ [1]
© UCLES 2014 0620/51/M/J/14

5
(g) What does test (f) tell you about solid U?
.............................................................................................................................................. [1]
(h) Name the gas given off in test (c).
.............................................................................................................................................. [1]
(i) What conclusions can you draw about solid U?
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 18]

6
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© UCLES 2014 0620/51/M/J/14

7
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© UCLES 2014 0620/51/M/J/14

8
Test for anions

produced

aluminium (Al 3+)
Test for gases

© UCLES 2014 0620/51/M/J/14

0620 CHEMISTRY
0620/51 Paper 5 (Practical Test), maximum raw mark 40

initial and final volume boxes completed correctly (1)
difference box correctly completed (1)
comparable to supervisors (1) ± 2 cm3 [3]

initial and final volume boxes completed correctly (1)
difference box correctly completed (1)
comparable to supervisors (1) ± 2 cm3
all readings to 1 dp (1) [4]
(c) fizzing / bubbles, etc. (1) [1]
(d) (i) pink (1)

not: purple
to colourless (1)
not: clear [2]
(ii) orange / pink (1) [1]
(e) (i) alkalis (1)

not: bases [1]
(ii) carbonate / carbon dioxide (1) [1]
(f) (i) difference in expt 1 – difference in expt 2 (1)

cm3 (1) [2]
(ii) 2 × difference in expt 2 (1) [1]
(iii) greater volume needed to react with T (1)

allow: ecf from (i) and (ii) [1]
(g) (i) 4 × difference value expt 1 (1)

4 × difference value expt 2 (1)
four times volume of solution R (1) [3]
(ii) volume of acid used > 50 cm3 / more than burette can hold (1)
set up two burettes / fill burette twice (1) [2]

guidance: reference to impurities (max 1)

2 tests on solid U
(a) pink (1)
powder / crystals (1) [2]
(b) drops / condensation (1)
blackens / brown / dark solid (1) [2]
(c) any five from:

beige / (pale) brown (1)
precipitate (1)
fizzes / bubbles (1)
glowing splint (1)
relights (1)
black / darkens (1) [5]
(d) beige / (pale) brown precipitate (1) [1]
(e) white (1)
precipitate (1) [2]
(f) no reaction / change / no precipitate (1) [1]
(g) not a chloride / halide (1) [1]
(h) oxygen / O2 (1) [1]
(i) any three from:

sulfate (1)
hydrated salt (1)
transition metal (1)
catalyst (1) [3]


CHEMISTRY 0620/61
1 hour

IB14 06_0620_61/2RP
2
1 A student separated a mixture of two alcohols, ethanol (boiling point 78 C) and
butanol (boiling point 118 C).
The apparatus used is shown below.
mixture of
alcohols
heat
(a) Complete the boxes to identify the pieces of apparatus labelled. [2]
(b) Label the arrows. [1]
(c) State the name of this separation process.
.............................................................................................................................................. [2]
(d) (i) Which liquid is first to collect in the beaker?
....................................................................................................................................... [1]
(ii) How would the student know when all of this liquid had collected?
.............................................................................................................................................
....................................................................................................................................... [1]
© UCLES 2014 0620/61/M/J/14

3
(e) Identify and explain a possible hazard in this experiment.
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 9]
2 The following paragraph was taken from a student’s notebook.
Preparation of lead chloride
10 cm3 of aqueous lead nitrate was placed in a beaker and 10 cm3 of aqueous potassium
chloride added. Lead chloride, a white solid, was formed. The solid was separated from the
mixture.
Water was then added to the solid and the mixture boiled. A clear liquid was formed. On
cooling, white crystals were deposited.
(a) What type of chemical reaction resulted in the formation of the lead chloride?
.............................................................................................................................................. [1]
(b) What is the solubility of lead chloride in
(i) cold water, ..........................................................................................................................
(ii) hot water? ..................................................................................................................... [2]
(c) What method should be used to separate the crystals from the mixture?
.............................................................................................................................................. [1]
[Total: 4]

4
3 A student investigated the reaction of zinc powder with dilute hydrochloric acid using the apparatus
below.
gas syringe
hydrochloric acid
zinc
The same mass of zinc was added to different volumes of hydrochloric acid at room temperature,
20 C. The total volume of hydrogen gas given off in each experiment was measured.
(a) Use the gas syringe diagrams to record the volumes of hydrogen gas in the table.
volume of
volume of hydrogen gas
hydrochloric acid gas syringe diagram
/ cm3
/ cm3
0 10 20 30 40 50 60
0
0 10 20 30 40 50 60
5
0 10 20 30 40 50 60
10
0 10 20 30 40 50 60
15
0 10 20 30 40 50 60
20
0 10 20 30 40 50 60
30
0 10 20 30 40 50 60
40
[3]
© UCLES 2014 0620/61/M/J/14

5
(b) On the grid, plot the points and draw a smooth line graph.
60
40
volume of
hydrogen
gas / cm3
20
0
0 10 20 30 40
volume of hydrochloric acid / cm3
[4]
(c) (i) Which point is inaccurate?
....................................................................................................................................... [1]
(ii) Suggest a possible reason for this inaccurate measurement.
....................................................................................................................................... [1]
(iii) Use your graph to work out the volume that would be expected to be formed.
Show clearly on the grid how you got your answer.
....................................................................................................................................... [2]
(d) Explain why the volume of hydrogen gas does not increase after 30 cm3 of hydrochloric acid.
....................................................................................................................................................
.............................................................................................................................................. [2]
(e) Sketch on the grid the graph you would expect if the experiments were repeated using the
same mass of zinc granules. [2]
[Total: 15]

6
4 A student investigated the reaction between dilute hydrochloric acid and an aqueous alkaline
solution R, containing two different substances, S and T.
Experiment 1
Using a measuring cylinder, 25 cm3 of solution R was poured into a conical flask and five drops of
phenolphthalein were added to the flask.
A burette was filled with hydrochloric acid up to the 0.0 cm3 mark. Hydrochloric acid was added to
the solution R and the flask shaken. Addition of hydrochloric acid was continued until the colour just
disappeared.
The mixture in the flask was kept for Experiment 2.
(a) Use the burette diagram to record the final volume in the table of results and complete the
table.
16
17
18
final burette reading
burette readings
final volume / cm3
difference / cm3
[3]
Experiment 2
Five drops of methyl orange indicator were added to the mixture in the flask from Experiment 1. The
mixture turned yellow. The initial volume reading of the burette was the same as the final reading
in Experiment 1. Hydrochloric acid was added from the burette to the mixture in the flask and the
mixture shaken.
The volume of hydrochloric acid added was recorded when the indicator just changed colour.
(b) Use the burette diagram to record the final volume in the table of results and complete the
table.
24
25
26
burette readings
final volume / cm3
difference / cm3
[3]
© UCLES 2014 0620/61/M/J/14
7
(c) Experiment 3
Hydrochloric acid was added to about 5 cm3 of solution R in a test-tube.
Rapid effervescence was observed.
(d) When phenolphthalein indicator was used in Experiment 1 the colour changed
from pink to .......................................................................................................................... [1]
(e) In a similar experiment, methyl orange indicator was used in Experiment 1 followed by
phenolphthalein in Experiment 2.
Suggest why this experiment would not work.
....................................................................................................................................................
.............................................................................................................................................. [1]
(f) What conclusion can you draw from Experiment 3?
.............................................................................................................................................. [1]
(g) The volume of hydrochloric acid added in Experiment 1 reacted with all of substance S and half
of substance T.
The volume of hydrochloric acid in Experiment 2 reacted with half of substance T.
(i) Work out the volume of hydrochloric acid which reacted with substance S.
....................................................................................................................................... [2]
(ii) Work out the volume of hydrochloric acid which reacted with substance T.
....................................................................................................................................... [1]
(iii) Compare the volumes of hydrochloric acid which reacted with substances S and T.
....................................................................................................................................... [1]
(h) (i) The experiments were repeated using 100 cm3 of solution R.
Predict the volume of hydrochloric acid which would be added in Experiments 1 and 2.
Experiment 1 ......................................................................................................................
Experiment 2 ......................................................................................................................
Explanation ................................................................................................................... [3]
(ii) Suggest a practical problem that would occur when carrying out these repeat experiments
and how you could solve this problem.
.............................................................................................................................................
....................................................................................................................................... [2]
[Total: 18]

8
5 A solid U was analysed. U was a soluble metal sulfate.

The tests on U, and some of the observations are in the following table.
Complete the observations.
tests observations
tests on solid U
(a) Appearance of solid U. pink crystals
(b) Solid U was heated gently and then

strongly in a test-tube. condensation droplets formed on the sides of the test-tube
(c) Solid U was added to distilled

water in a test-tube and shaken
until dissolved.
The solution was divided into
three equal portions in separate
test-tubes and the following tests
carried out.
Several drops of aqueous sodium

hydroxide were added to the first
portion of the solution and the pale brown precipitate
test-tube shaken.
Then hydrogen peroxide solution effervescence

was added to the mixture and the glowing splint relit
gas given off tested.
(d) Dilute nitric acid was added to ............................................................................................

the second portion of the solution
followed by barium nitrate solution. ...................................................................................... [2]
(e) Dilute nitric acid was added to the

third portion of the solution followed
by silver nitrate solution. ...................................................................................... [1]
© UCLES 2014 0620/61/M/J/14

9
(f) What does test (e) tell you about solid U?
.............................................................................................................................................. [1]
(g) Name the gas given off in test (c).
.............................................................................................................................................. [1]
(h) What conclusions can you draw about solid U?
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 7]

10
6 Nuts contain oil. Nuts can be burned to produce energy. The apparatus shown can be used to
compare the energy produced by burning different nuts.
thermometer
water
nut
Plan an investigation to show which of three different types of nut produce the most energy. You are
provided with peanuts, brazil nuts and hazelnuts.
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
..................................................................................................................................................... [7]
[Total: 7]
© UCLES 2014 0620/61/M/J/14

11
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© UCLES 2014 0620/61/M/J/14

12
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© UCLES 2014 0620/61/M/J/14

0620 CHEMISTRY
1 (a) thermometer (1)
condenser (1)
allow condensing tube, condensating tube, etc. [2]
(b) arrows labelled – water (in) and water (out) (1) [1]
(c) fractional (1)
distillation (1) [2]
(d) (i) ethanol (1) [1]
(ii) temperature would rise (above 78 oC) (1) [1]
(e) alcohols are (in)flammable / catch fire / burn (1)

ignore: explode
Bunsen burner / flame / heat (1) [2]
2 (a) precipitation / double decomposition (1) [1]

allow: ppt
(b) (i) low / insoluble / does not dissolve (1) [1]
(ii) high / soluble / dissolves (1) [1]
(c) filtration (1) [1]
3 (a) volumes of hydrogen completed correctly (3)

0, 8, 34, 42, 46, 48, 48 [3]
guidance: 7 correct (3); 6 correct (2); 5 correct (1); 4 or fewer correct (0)
(b) points plotted correctly including origin (3)

guidance: 7 correct (3); 6 correct (2); 5 correct (1); 4 or fewer correct (0)
smooth curve missing anomalous point (1) [4]

(c) (i) point at 5 cm3 / 8 cm3 H2 / second point (1) [1]
(ii) leak / loss / escape of gas or wrong amount / too little HC l or zinc (1) [1]
allow: syringe sticking
(iii) reading from graph (1) ± half small square
indication on graph (1) [2]
(d) excess acid (1)
all zinc reacted (1) [2]

allow: used up
(e) sketch curve identical (2)
different curve levelling out at 48 cm3 (1) [2]

note: must be some indication of a second curve
initial and final volume boxes completed correctly (1) 0.0 and 16.8
difference box correctly completed (1) 16.8
all readings to one decimal place (1) [3]
initial (1) and final volume (1) boxes completed correctly 16.8 (1) and 25.2 (1)
difference box correctly completed (1) 8.4 [3]
(d) to colourless (1) [1]

not: clear
(e) coloured reacting mixture masks colour of phenolphthalein / reaction is finished / solution is
acidic (1) [1]
(f) carbonate / carbon dioxide present (1) [1]

allow: hydrogencarbonate

(g) (i) 8.4 (1)

ecf: titre 1 – titre 2
cm3 (1) [2]
(ii) 16.8 (1) [1]

ecf: 2 × titre 2
(iii) twice volume of acid needed to react with T (1) [1]

ecf: if (g)(i) or / and (g)(ii) wrong need quantitative link.
not: more (unqualified)
(h) (i) 67.2 cm3 (1)
33.6 cm3 (1)
4 × volume of solution R (1) [3]
(ii) volume of acid used > 50 cm3 / more than burette can hold (1)
set up more than two burettes / 100.8 won’t fit into 2 (1) [2]
allow: impurities / contamination (1)
5 (d) white (1)
precipitate (1) [2]
(e) no reaction / no change / no precipitate (1) [1]

allow: colourless solution
(f) not a chloride / halide (1) [1]
(g) oxygen / O2 (1) [1]

not O
(h) transition metal / manganese (1)
hydrated salt (1)

ignore: sulfate
allow: catalyst (1) max [2]

6 same / measured volume of water (1)
initial temperature (1)
mass of nut(s) (1)
ignite / burn (1)

not: heat
for suitable time < 10 minutes / to completion (1)
final temperature of water (1)
repeat with other nut(s) (1)
compare / conclusion (1) max [7]

CHEMISTRY 0620/11
45 Minutes
Soft clean eraser
*4319041575*

IB15 06_0620_11/3RP
2
1 The changes that occur when a substance changes state are shown below.
W X
solid liquid gas
Z Y
Which process, W, X, Y or Z, is occurring in the following four situations?
1 Butter melts on a warm day.

2 Water condenses on a cold surface.
3 The volume of liquid ethanol in an open beaker reduces.
4 Ice forms inside a freezer.
1 2 3 4
A W X Y Z
B W Y X Z
C X Y Z W
D X Z Y W
2 A student uses the apparatus shown in the diagram below to measure the volume of carbon
dioxide gas made when different masses of marble chips are added to 25 cm3 of dilute
hydrochloric acid.
gas syringe
bung
25 cm3 dilute
hydrochloric acid
marble chips
Which other items of apparatus are needed?
A funnel and balance

B funnel and stopwatch
C measuring cylinder and balance
D measuring cylinder and stopwatch
© UCLES 2015 0620/11/M/J/15

3
3 Atoms contain electrons, neutrons and protons.
What is the definition of nucleon number?
A the number of neutrons in the nucleus of an atom

B the number of protons in the nucleus of an atom
C the total number of neutrons and protons in the nucleus of an atom
D the total number of particles in an atom
4 The diagram shows the atomic structure of an element X.
key
e
p proton
n n e electron
p
p n p
n neutron
n p n
What is X?
A aluminium
B beryllium
C boron
D fluorine
5 Which statements comparing the properties of electrons, neutrons and protons are correct?
neutrons and protons are only electrons and

both heavier than electrons neutrons are charged
A
B
C
D

4
6 Rescuers are drilling through fallen rock in order to rescue some men trapped in a cave. The drill
needs lubricating from time to time.
The following statements were made about the materials used for the drill tip and the lubricant
and the reasons for their use.
1 Diamond was used for the drill tip as it does not conduct electricity.
2 Diamond was used for the drill tip as it is very hard.
3 Graphite was used as the lubricant as it conducts electricity.
4 Graphite was used as the lubricant as it is soft and flaky.
7 In which compounds are pairs of electrons shared between atoms?
1 methane
2 lead bromide
3 sodium chloride
A 1 only B 2 only C 1 and 3 D 1, 2 and 3
8 What is the relative formula mass, Mr, of CaCO3?
A 50 B 68 C 100 D 204
9 Copper and hydrogen can each be formed by electrolysis.
At which electrodes are these elements formed?
copper hydrogen
A anode anode
B anode cathode
C cathode anode
D cathode cathode
© UCLES 2015 0620/11/M/J/15

5
10 The diagram shows a failed attempt to copper-plate a pan.
3V
– +
copper cathode pan
copper sulfate
solution
Which action will plate the pan with copper?
A cooling the copper sulfate solution in an ice bath

B heating the copper sulfate solution to boiling point
C increasing the voltage from 3 V to 6 V
D making the pan the cathode and the copper the anode

6
11 The diagrams show four chemical reactions.
Which reaction is endothermic?
A B
steam flame
water
natural gas
calcium oxide
addition of water to calcium oxide combustion of natural gas
C D
final temperature
initial temperature
alkali
heat acid
thermal decomposition of limestone reaction of acid with alkali
© UCLES 2015 0620/11/M/J/15

7
12 Powdered marble reacts with hydrochloric acid using the apparatus shown.
The gas syringe fills in 36 seconds.
gas syringe
gas
powdered hydrochloric acid

marble
The experiment is repeated using marble chips in place of powdered marble.
How long does it take to fill the gas syringe in this experiment?
A 9 seconds
B 18 seconds
C 36 seconds
D 72 seconds
13 When pink crystals of cobalt(II) chloride are heated, steam is given off and the colour of the solid
changes to blue.
CoCl 2.6H2O CoCl 2 + 6H2O
What happens when water is added to the blue solid?
colour temperature
A changes to pink decreases

B changes to pink increases
C remains blue decreases
D remains blue increases

8
14 In which change is chromium(II) oxide, CrO, reduced?
CrO3
B
A
Cr CrO CrO2
C
D
Cr2O3
15 The table shows the pH of four aqueous solutions, W, X, Y and Z.
substance pH
W 7
X 9
Y 2
Z 5
Universal Indicator is added to each solution.
Which row shows the colour of each solution after the indicator is added?
W X Y Z
A blue green orange red

B green blue red orange
C orange red blue green
D red orange green blue
16 Hydrochloric acid is used to clean metals.
The acid reacts with the oxide layer on the surface of the metal, forming a salt and water.
Which word describes the metal oxide?
A alloy
B base
C element
D indicator
© UCLES 2015 0620/11/M/J/15

9
17 Four steps to prepare a salt from an excess of a solid base and an acid are listed.
1 crystallisation
2 evaporation
3 filtration
4 neutralisation
In which order are the steps carried out?
A 2→3→4→1
B 3→1→2→4
C 4→2→1→3
D 4→3→2→1
18 Which two compounds give a white precipitate when their aqueous solutions are mixed?
A silver nitrate and sodium chloride

B silver nitrate and sodium iodide
C sodium hydroxide and copper(II) sulfate
D sodium hydroxide and iron(II) chloride
19 Which element is in the same group of the Periodic Table as lithium?
electrical conductivity density in g / cm3
A high 0.97
B high 8.93
C low 0.07
D low 3.12
20 Which properties of the element titanium, Ti, can be predicted from its position in the Periodic
Table?
can be used conducts electricity forms coloured

has low density
as a catalyst when solid compounds
A
B
C
D

10
21 The following statements are about elements in the Periodic Table.
1 Their atoms have a full outer shell of electrons.

2 They form basic oxides.
3 They are found in Group 0.
4 They are present in small quantities in the air.
Which statements are correct for the noble gases?
22 In the outline of the Periodic Table below, some elements are shown as numbers.
1 2
3 4
5 6
7
Which two numbers are metals in the same period?
23 Solder is an alloy of lead and tin. It is used for joining pieces of metal.
heated solder
molten solder
metal
Which statement about solder is correct?
A It can be represented by a chemical formula.

B It contains a mixture of lead and tin.
C It contains lead and tin chemically combined.
D It has a higher melting point than lead or tin.
© UCLES 2015 0620/11/M/J/15

11
24 What is a major use of aluminium?
A making brass
B making cutlery
C making electrical wiring
D making food containers
25 Which row describes the conditions used to make steel from the iron produced by a blast
furnace?
calcium oxide
oxygen heat
(lime)
A
B
C
D
26 W, X, Y and Z are four metals.
Some properties of these metals are listed below.
1 Only W and Z can be extracted by reduction of their oxides with carbon.

2 Only X will react with cold water.
3 Only Z can be found ‘native’ (not combined with any other element).
What is the correct order of these metals in the reactivity series (most reactive first)?
A X, W, Y, Z B X, Y, W, Z C Z, W, Y, X D Z, Y, W, X
27 The diagram shows stages in producing drinking water.
In which tank is chlorine added to the water?
A B C D
sedimentation filtration anti-bacterial storage mains
reservoir
tank tank treatment tank tank supply
28 Which gas is not found in clean air?
A carbon dioxide
B carbon monoxide
C nitrogen
D oxygen

12
29 Which combination of chemical compounds could be used to produce the fertiliser shown?
N P K
21 : 16 : 8
SUPERGROW
A (NH4)3PO4, KCl
B NH4NO3, Ca3(PO4)2
C NH4NO3, CO(NH2)2
D NH4NO3, K2SO4, (NH4)2SO4
30 The pollutants released into the air from car exhausts and some power stations include oxides of
the type XO and YO2.
What are X and Y?
X Y
A carbon only nitrogen only

B carbon only nitrogen and sulfur only
C carbon and nitrogen carbon and nitrogen only
D carbon and nitrogen carbon, nitrogen and sulfur
31 Which statement about rusting is not correct?
A Only oxygen is needed for rusting.

B Painting can stop iron gates rusting.
C Rust is hydrated iron(III) oxide.

D Water and oxygen are both needed for rusting.
32 Carbon dioxide and methane are ‘greenhouse gases’ which contribute to global warming.
Which process does not increase global warming?
A burning fossil fuels

B decay of organic waste
C farming cattle for beef
D growing crops such as sugar cane
© UCLES 2015 0620/11/M/J/15

13
33 These statements are about a gas.
1 It is produced by thermal decomposition of a carbonate.

2 It is produced by the fermentation of glucose.
3 It makes up 1% of unpolluted air.
4 It is produced during the production of steel from iron.
Which statements are correct for carbon dioxide?
A 1 and 2 only B 1, 2 and 3 C 1, 2 and 4 D 1, 3 and 4
34 The diagram represents a lime kiln.
waste gases
lime kiln
limestone
fuel in fuel in
air in air in
What leaves the furnace at X?
A calcium carbonate
B calcium hydroxide
C calcium oxide
D calcium sulfate

14
35 The structures of four organic compounds are shown.
H H H H H H H
H C H H C C H C C H C C O H
H H H H H H H
A Only one of the compounds is an alcohol.

B Only one of the compounds is an alkane.
C Only one of the compounds is unsaturated.
D Only three of the compounds are hydrocarbons.
36 Which statement about petroleum is not correct?
A It can be separated into useful substances by fractional distillation.

B It consists mainly of hydrocarbons.
C It is found underground in many parts of the world.
D Its main use is for making lubricants and polishes.
37 Which statement about alkane molecules is correct?
A They burn in oxygen.

B They contain carbon, hydrogen and oxygen atoms.
C They contain double bonds.
D They contain ionic bonds.
38 Which statements are correct for ethanoic acid?
1 It contains a carbon-oxygen double bond.

2 It contains two carbon atoms.
3 It decolourises bromine water.
4 It contains an –OH group.
A 1 and 2 only
B 1 and 3
C 1, 2 and 4
D 2, 3 and 4
© UCLES 2015 0620/11/M/J/15

15
39 A hydrocarbon A is cracked to make B and hydrogen.
Compound C is formed by the addition polymerisation of B.
To which homologous series do A, B and C belong?
alkene alkane
A A B and C
B B A and C
C C A and B
D – A and C
40 By which of the following methods is ethanol formed?
1 fractional distillation of petroleum

2 fermentation
3 catalytic addition of steam to ethene
A 1 and 2 only
B 1 and 3 only
C 2 and 3 only
D 1, 2 and 3
© UCLES 2015 0620/11/M/J/15

© UCLES 2015
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
www.cie.org.uk after the live examination series.

Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/11/M/J/15
Indium Iodine
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
0620 CHEMISTRY
Cambridge is publishing the mark schemes for the May/June 2015 series for most
Cambridge IGCSE®, Cambridge International A and AS Level components and some

Cambridge IGCSE – May/June 2015 0620 11
Question Question
Key Key
Number Number
1 B 21 C
2 C 22 D
3 C 23 B
4 B 24 D
5 B 25 A
6 D 26 B
7 A 27 C
8 C 28 B
9 D 29 A
10 D 30 D
11 C 31 A
12 D 32 D
13 B 33 C
14 A 34 C
15 B 35 B
16 B 36 D
17 D 37 A
18 A 38 C
19 A 39 B
20 B 40 C

*1564763095*
CHEMISTRY 0620/21
1 hour 15 minutes

IB15 06_0620_21/2RP
2
1 The structures of six substances containing carbon are shown below.
A B C
Ca2+ CO32– Ca2+ CO32– H H
O C O H C C H
CO32– Ca2+ CO32– Ca2+
H H
Ca2+ CO32– Ca2+ CO32–
CO32– Ca2+ CO32– Ca2+
D E F
C C
C
C C
C C H H Zn2+ CO32– Zn2+ CO32–
C
C C C C
C C C
C C C C
C
CO32– Zn2+ CO32– Zn2+
H H
C C Zn2+ CO32– Zn2+ CO32–
C C C C
C C C C
C C C C
C
C C
C C C CO32– Zn2+ CO32– Zn2+
C C
Answer the following questions about these substances.

(a) Which substance, A, B, C, D, E or F,
(i) is an element, .......................... [1]
(ii) is a saturated hydrocarbon, .......................... [1]
(iii) is added to the blast furnace to help in the extraction of iron, .......................... [1]
(iv) has a giant covalent structure, .......................... [1]
(v) is a product of respiration, .......................... [1]
(vi) contains a metal ion with 20 protons? .......................... [1]
(b) Complete the word equation for the thermal decomposition of substance B.
heat
............................................... calcium oxide + ...............................................
[2]
(c) Describe a test for substance A.
test .............................................................................................................................................
result ..........................................................................................................................................
[2]
[Total: 10]
© UCLES 2015 0620/21/M/J/15

3
2 A small piece of sodium is added to some ethanol. The temperature was measured before and after
the sodium was added.
19 °C 29 °C
sodium
ethanol
(a) Explain how this experiment shows that the reaction is exothermic.
.............................................................................................................................................. [1]
(b) Complete the structure of ethanol to show all atoms and bonds.
H C
H
[1]

4
(c) Ethanol can be made by the reaction of steam with ethene.
(i) Write the word equation for this reaction.
....................................................................................................................................... [1]
(ii) What conditions are needed for this reaction?

Tick two boxes.
enzyme catalyst
high temperature (300 °C)
low temperature (10 °C)
phosphoric acid catalyst
presence of light
[2]
(iii) What will be observed when ethene is bubbled through aqueous bromine?
....................................................................................................................................... [1]
(d) Ethanol can also be made by fermentation.

The fermentation mixture contains solids as well as an aqueous solution of ethanol.
Suggest how the ethanol can be purified from this fermentation mixture.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 9]
© UCLES 2015 0620/21/M/J/15

5
3 The diagram shows the apparatus used for the electrolysis of molten sodium bromide.
+ –
S U
(a) (i) What does the term electrolysis mean?
.............................................................................................................................................
....................................................................................................................................... [1]
(ii) Which letter, R, S, T or U, in the diagram above represents the cathode?
.......................... [1]
(b) Complete the word equation for the electrolysis of molten sodium bromide.
sodium bromide → ...................................... + ......................................

[2]
(c) A solution of sodium bromide in water is neutral.
Which one of the following pH values is neutral?

pH 0 pH 6 pH 7 pH 10 pH 14
[1]

6
(d) The diagram below shows the arrangement of the particles in sodium bromide at room
temperature.
Na+ Br – Na+ Br –
P
Br – Na+ Br – Na+
(i) Give the name of the type of particles, P, present in sodium bromide.
....................................................................................................................................... [1]
(ii) What is the state of sodium bromide at room temperature?

Use the information in the diagram to explain your answer.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(e) Sodium bromide can be made by heating sodium in bromine vapour.
Complete the balanced symbol equation for this reaction.
....... Na + ........... → 2NaBr

[2]
(f) Bromine has two naturally-occurring isotopes.
What is the meaning of the term isotope?
....................................................................................................................................................
.............................................................................................................................................. [1]
[Total: 11]
© UCLES 2015 0620/21/M/J/15

7
4 A student investigated the reaction of magnesium with dilute hydrochloric acid.
Mg(s) + 2HCl (aq) → MgCl 2(aq) + H2(g)
She measured the volume of gas given off at various times during the reaction.
(a) Complete the diagram of the apparatus she would use to measure the volume of the gas given
off.
Label the apparatus.
flask
hydrochloric
acid
magnesium
ribbon
[3]

8
(b) The student carried out the reaction at 25 °C using magnesium ribbon.
Her results are shown below.
60
50
40
volume of
gas / cm3 30
20
10
0
0 20 40 60 80 100 120 140
time / seconds
(i) How long does it take for the reaction to stop?
............. seconds [1]
(ii) What is the volume of hydrogen made after 20 seconds?
............. cm3 [1]
(iii) On the grid above, draw a line to show how the volume of gas changes when the experiment
is carried out at 15 °C and all other conditions remain the same. [2]
(iv) The student repeated the experiment using magnesium powder. All other conditions
remain the same.
How does the rate of reaction with magnesium powder compare with the rate of reaction
with magnesium ribbon?
....................................................................................................................................... [1]
© UCLES 2015 0620/21/M/J/15

9
(c) (i) Draw a diagram to show the electron arrangement in a molecule of hydrogen.
[1]
(ii) What type of bonding is present in a hydrogen molecule?
....................................................................................................................................... [1]
(d) Magnesium chloride is a salt.

Magnesium sulfate is also a salt.
Give the name of two compounds which react together to form magnesium sulfate.
.................................................................. and ................................................................... [2]
[Total: 12]

10
5 The structure of glycolic acid is shown below.
H O
H C C
O O H
H
(a) On the structure above, put a ring around the carboxylic acid functional group. [1]
(b) Glycolic acid is prepared by heating a mixture of methanal, carbon monoxide and water with a
sulfuric acid catalyst.
(i) The formula of methanal is HCHO.
Calculate the relative molecular mass of methanal.
[1]
(ii) What is the function of the catalyst?
....................................................................................................................................... [1]
(iii) State one adverse effect of carbon monoxide on humans.
....................................................................................................................................... [1]
(c) Glycolic acid can also be prepared by the reduction of oxalic acid.
(i) What does the term reduction mean?
....................................................................................................................................... [1]
(ii) Give the name of the reducing agent in the following reaction.
heat
2CuO(s) + C(s) → 2Cu(s) + CO2(g)
name of reducing agent ................................................................................................ [1]
© UCLES 2015 0620/21/M/J/15

11
(d) Glycolic acid is found in unripe grapes.

Grape skins contain a number of different coloured pigments.
Describe how you could obtain a solution of these pigments from grape skins.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(e) Glycolic acid can undergo polymerisation.

Ethene can also undergo polymerisation.
The equation for the polymerisation of ethene is shown below.
catalyst
ethene poly(ethene)
high temperature
Give the name of the monomer in this equation.
.............................................................................................................................................. [1]
(f) Long chain alkanes can be cracked to produce shorter chain alkanes and alkenes.
(i) What conditions are needed for cracking?
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Complete the equation for the cracking of hexadecane, C16H34, to form octane, C8H18, and
ethene only.
C16H34 → C8H18 + ...... C2H4

[1]
[Total: 13]

12
6 The table shows some physical properties of the metals, A, B, C and D.
electrical density boiling point

metal hardness
conductivity in g / cm3 / °C
A fairly good 8.64 765 hard

B good 0.97 883 soft
C good 7.14 907 hard
D good 0.86 760 soft
(a) (i) Which two metals in the table are Group I metals?
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) None of the metals A, B, C or D are transition elements.
Give two properties of transition elements or their compounds that make them different
from metals A, B, C and D.
.............................................................................................................................................
....................................................................................................................................... [2]
(iii) Cobalt is a transition element.

When it is heated very strongly in steam, hydrogen is given off.
...... Co(s) + 4H2O(g) → Co3O4(s) + ...... H2(g)

[2]
(iv) Iron is also a transition element.
Describe how iron is converted to steel.

In your answer, refer to basic oxides and oxygen.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
© UCLES 2015 0620/21/M/J/15

13
(b) When lithium reacts with water it moves about on the surface of the water, bubbles are seen
and the lithium disappears slowly.
Predict how the reaction of potassium with water compares with the reaction of lithium with
water.
• any differences in observations,

• the names of the products formed when lithium and potassium react with water.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]
[Total: 14]

14
7 (a) A student took two identical syringes.

He filled one with water and the other with helium gas and sealed the end of both syringes.
He then pushed the syringe plungers with equal force.
The diagram shows what happened.
syringe
plunger
syringe
water helium
Describe and explain these results using ideas about particles in liquids and gases.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
© UCLES 2015 0620/21/M/J/15

15
(b) The table shows some properties of the Group 0 elements helium, neon, argon and krypton.
density of the
electron melting point boiling point
element liquefied gas
arrangement / °C / °C
in g / cm3
helium 2 0.15 –272 –269
neon 1.20 –248 –245
argon 2,8,8 1.40 –189 –186
krypton 2,8,18,8 2.15 –157 –152
(i) Describe how the density of the liquefied noble gases changes down Group 0.
....................................................................................................................................... [1]
(ii) Deduce the electron arrangement of neon.
....................................................................................................................................... [1]
(iii) What is the state of argon at –188 °C?
....................................................................................................................................... [1]
(iv) Which element in the table has the highest melting point?
....................................................................................................................................... [1]
(c) The table below shows the number of electrons, protons and neutrons in some isotopes of
helium, argon and neon.
Complete the table.

element
electrons protons neutrons
3
2 He 2 2
.................
38
18 Ar 18 20
.................
10 10 11
.................
[3]
[Total: 11]

© UCLES 2015
DATA SHEET
the live examination series.

Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/21/M/J/15
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
0620 CHEMISTRY

Abbreviations used in the Mark Scheme
• ; separates marking points

• / separates alternatives within a marking point
• OR gives alternative marking point
• R reject
• I ignore mark as if this material was not present
• A accept (a less than ideal answer which should be marked correct)
• COND indicates mark is conditional on previous marking point
• owtte or words to that effect (accept other ways of expressing the same idea)
• max indicates the maximum number of marks that can be awarded
• ecf credit a correct statement that follows a previous wrong response
• ( ) the word / phrase in brackets is not required, but sets the context
• ORA or reverse argument

Question Answer Marks Guidance
1(a)(i) D / graphite / carbon; 1

1(a)(ii) C / ethane; 1
1(a)(iii) B / CaCO3 / calcium carbonate; 1 A D / carbon
1(a)(iv) D / graphite / carbon; 1
1(a)(v) A / CO2 / carbon dioxide; 1
1(a)(vi) B / calcium / calcium carbonate / Ca2+; 1
1(b) calcium carbonate; I CaCO3
carbon dioxide; 2 I CO2
1(c) limewater / calcium hydroxide / Ca(OH)2;
COND turns milky / turns cloudy / gives a white precipitate; 2
2(a) temperature rises; 1 A gives off heat

I bubbles given off
2(b) structure of ethanol completed correctly; 1 A OH in place of O–H
2(c)(i) ethene + water → ethanol; 1 A ethene + steam → ethanol
A correct symbol equation
I steam over the arrow
2(c)(ii) 2nd and 4th boxes ticked (one mark each); 2
2(c)(iii) (aqueous bromine) decolourised / goes colourless; 1 I aqueous bromine goes clear / discoloured
I incorrect colour of bromine
A colourless solution

2(d) filter (off the solids);

distillation; A boil and condense
I heat / boil unqualified
one of:
• (distil) filtrate;
• fractional (distillation) / fractionating (column); 3
3(a)(i) breakdown / decomposition of compound using electricity; 1 A separation of compounds to elements using
electricity
A substances in place of compounds
A breakdown of ionic bonds using electricity
I separation of elements by electricity / plating using
electricity / separation of compounds to elements
unqualified / separating metals by electricity
3(a)(ii) U; 1
3(b) sodium / Na; R sodium ions
bromine / Br2; 2 R bromide / bromine water / Br
3(c) pH 7; 1
3(d)(i) ions / cations and anions; 1 A ionic / ionic bond
I cations on own / anions on own
3(d)(ii) solid
(particles / ions) close together; A atoms or molecules for ions
A packed together / no spaces / attached to each other /
held together
I comments about movement
(particles / ions) regularly arranged / in rows / lattice; 2 A fixed shape / fixed positions
I neat structure / reference to electrostatic forces
3(e) Br2;
2(Na); 2
3(f) atoms with same number of protons but different number of neutrons / A nucleon number for mass number
atoms with same atomic number but different number of neutrons / A elements with same number of protons but different
atoms with same number of protons but different mass number; 1 number of neutrons / atoms of same elements with
different numbers of neutrons
I atoms / elements with different (relative) atomic
masses
I same elements with different numbers of neutrons
I reference to molecules
I different neutrons (no number)

4(a) (gas) syringe or measuring cylinder correctly labelled; A burette / graduated test-tube drawn and labelled test-
tube
(gas) tube leading from closed apparatus to flask or from inverted measuring R if tube goes to surface of water or under water in
cylinder with mouth underwater to flask; reaction flask
COND workable apparatus and apparatus airtight / no gaps in apparatus; 3

4(b)(i) 44–48 (seconds); 1
4(b)(ii) 41 (cm3); 1
4(b)(iii) initial gradient less than the original line AND starting at 0–0; A straight line instead of curved line
ends up at same final volume; 2 A line not reached final volume but still going up and
likely to reach final volume
A final horizontal line two small squares below the 25 ºC
line
R if a single straight line is drawn from 0–0 to point
49–140
4(b)(iv) increased (rate) / faster (rate) / quicker; 1 I reference to time unless it contradicts increased rate
4(c)(i) pair of electrons between two (hydrogen) atoms; 1 hydrogen atoms do not have to be labelled H
4(c)(ii) covalent; 1 I single bond
4(d) sulfuric acid; A correct formulae
magnesium oxide / magnesium hydroxide / magnesium carbonate; 2 R magnesium

5(a) COOH group circled; 1

5(b)(i) 30; 1
5(b)(ii) speeds up reaction / increases rate (of reaction); 1 A lowers the activation energy / allows the reaction to
occur by more favourable mechanism
5(b)(iii) poisonous / toxic / death; 1 A harmful / makes breathing difficult / respiratory
problems
A combines with haemoglobin / reduces the amount of
oxygen in the blood / stops you breathing / asphyxiation /
suffocates you
I lung cancer / lung damage
5(c)(i) gain of electrons / loss of oxygen / decrease in oxidation number; 1 A gain of hydrogen
5(c)(ii) carbon; 1 AC
5(d) grind grape skins / blend skins / crush skins; A crush grapes
I grapes squeezed
(grape skins) in water / in solvent / in named solvent; NOTE: mark for the idea that the grape skins are in
solvent but NOT solvent in context of chromatography.
I grapes in acids / alkalis
filter (off the solid / grape skins); 3
5(e) ethene; 1 A alkene
5(f)(i) high temperature; A heat / stated temperatures between 200–1000 oC
catalyst / aluminium oxide / zeolites; 2 A absence of oxygen (for 2nd mark)
I high pressure / enzymes (unqualified) / oxygen
5(f)(ii) 4 (C2H4); 1


6(a)(i) B and D;
they have low(er) density / they are soft; 2 A they have densities of 0.97 and 0.86 / light(weight)
I comments about conductivity and boiling point
6(a)(ii) Any two of:
• high densities; A heavy for high density
• high melting points / high boiling points;
• catalysts;
• (compounds have) variable valency / variable oxidation numbers / form
ions with different charges;
• form coloured compounds; A they are coloured for coloured compounds
• form complex ions; 2
A hard BUT not hardness / medium hard
6(a)(iii) 3 (Co);
4 (H2); 2
6(a)(iv) Any 3 of:
• oxygen blown through molten iron / oxygen added to molten iron;
• (oxygen) reacts with impurities / carbon / silicon / phosphorus;
• oxides formed; I (oxygen) oxidises iron / bonds to iron
• calcium oxide added / lime added / limestone / calcium carbonate added; A suitable named oxides including CO / CO2
• (calcium oxide) reacts with acidic oxides / silicon dioxide / oxides of
phosphorus;
• idea of slag being formed;
• statement about removal of impurities e.g. CO2 formed escapes as
gas / slag removed from surface of molten iron;
• other metals added; 3
R iron bonds with other metals

6(b) (lithium) hydroxide / (potassium) hydroxide; A correct formulae
hydrogen / H2;
3 marks from any 3 differences in observations e.g.

• more bubbles with K ORA;
• it / K moves faster (on water surface) ORA;
• Li does not catch fire / K catches fire / K bursts into flame;
• it / K fizzes more than Li ORA;
• it / K disappears rapidly; I smoke
• K explodes / lithium does not explode; A K spits / K pops
• K melts / ball with K / lithium does not melt / does not go into ball; 5
7(a) • liquids / water have particles close together / touching; A no spaces between particles
• gases / helium have particles far apart / room between gas particles / more
space between gas particles;
• volume of liquid does not decrease / liquid not compressed / liquid not A syringe is not reduced
squeezed / plunger does not move;
• volume of gas decreases / gas compressed / plunger moves; 4 A syringe is reduced
I there is room / not room (reference to space between
particles)
7(b)(i) increases / gets larger; 1 A becomes heavier
7(b)(ii) 2,8; 1 A 2 in the first shell and 8 in the second
7(b)(iii) liquid; 1
7(b)(iv) krypton; 1
7(c) He: number of neutrons = 1;
Ar: number of electrons = 18;
symbol for neon is
21
10 Ne ; 3

*1045436086*
CHEMISTRY 0620/31
1 hour 15 minutes

IB15 06_0620_31/FP
2
1 (a) Coal is a solid fossil fuel.
Name two other fossil fuels.
.............................................................................................................................................. [2]
(b) Two of the elements present in a sample of coal are carbon and sulfur.
A sample of coal was heated in the absence of air and the products included water, ammonia
and hydrocarbons.
Name three other elements present in this sample of coal.
.............................................................................................................................................. [2]
(c) Sulfur, present in coal, is one major cause of acid rain. Sulfur burns to form sulfur dioxide which
reacts with rain water to form sulfuric acid.
(i) Describe how the high temperatures in vehicle engines are another cause of acid rain.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(ii) Give two harmful effects of acid rain.
.............................................................................................................................................
....................................................................................................................................... [2]
(d) In 2010, a large coal-burning power station in the UK was converted to burn both coal and
wood.
Explain why the combustion of wood rather than coal can reduce the effect of the emissions
from this power station on the level of carbon dioxide in the atmosphere.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 12]
© UCLES 2015 0620/31/M/J/15

3
2 Iron from the Blast Furnace is impure. It contains about 5% of impurities, mainly carbon, sulfur,
silicon and phosphorus, which have to be removed when this iron is converted into steel.
(a) Explain how the addition of oxygen and calcium oxide removes these impurities. Include an
equation for a reaction of oxygen and a word equation for a reaction of calcium oxide in this
process.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
[5]
(b) Mild steel is the most common form of steel. Mild steel contains a maximum of 0.3% of carbon.
High carbon steel contains 2% of carbon. It is less malleable and much harder than mild steel.
(i) Give a use of mild steel.
....................................................................................................................................... [1]
(ii) Suggest a use of high carbon steel.
....................................................................................................................................... [1]
(iii) Explain why metals are malleable.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(iv) Suggest an explanation why high carbon steel is less malleable and harder than mild
steel.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
[Total: 12]

4
3 (a) The reactions between metals and acids are redox reactions.
Zn + 2H+ → Zn2+ + H2
(i) Which change in the above reaction is oxidation, Zn to Zn2+ or 2H+ to H2? Give a reason
for your choice.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Which reactant in the above reaction is the oxidising agent? Give a reason for your choice.
.............................................................................................................................................
....................................................................................................................................... [2]
(b) The rate of reaction between a metal and an acid can be investigated using the apparatus
shown below.
20 40 60 80 100
gas syringe
hydrochloric acid
zinc foil
A piece of zinc foil was added to 50 cm3 of hydrochloric acid, of concentration 2.0 mol / dm3. The
acid was in excess. The hydrogen evolved was collected in the gas syringe and its volume
measured every minute. The results were plotted and labelled as graph 1.
graph 2 (with copper)
graph 1
volume
0
0 time
The experiment was repeated to show that the reaction between zinc metal and hydrochloric
acid is catalysed by copper. A small volume of aqueous copper(II) chloride was added to the
acid before the zinc was added. The results of this experiment were plotted on the same grid
and labelled as graph 2.
© UCLES 2015 0620/31/M/J/15

5
(i) Explain why the reaction mixture in the second experiment contains copper metal. Include
an equation in your explanation.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Explain how graph 2 shows that copper catalyses the reaction.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(c) If the first experiment was repeated using ethanoic acid, CH3COOH, instead of hydrochloric
acid, how and why would the graph be different from graph 1?
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
(d) Calculate the maximum mass of zinc which will react with 50 cm3 of hydrochloric acid, of
concentration 2.0 mol / dm3.
Zn + 2HCl → ZnCl 2 + H2
Show your working.
[3]
[Total: 16]

6
4 The alcohols form a homologous series.
(a) (i) Give three characteristics which all members of a homologous series share.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(ii) Give the name of the third member of this series.
name ......................................... [1]
(iii) Deduce the molecular formula of the alcohol whose Mr = 158. Show your working.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(b) Explain why the following two alcohols are isomers.
CH3
CH3 C OH CH3 CH2 CH2 CH2 OH
CH3
....................................................................................................................................................
.............................................................................................................................................. [2]
© UCLES 2015 0620/31/M/J/15

7
(c) This question is based on typical reactions of butan-1-ol.
(i) When butan-1-ol, CH3–CH2–CH2–CH2–OH, is passed over the catalyst silicon(IV) oxide,
water is lost.
Deduce the name and the structural formula of the organic product in this reaction.
name .........................................
structural formula
[2]
(ii) Suggest the name of the ester formed from butanol and ethanoic acid.
....................................................................................................................................... [1]
(iii) Butan-1-ol is oxidised by acidified potassium manganate(VII).
Deduce the name and the structural formula of the organic product in this reaction.
name .........................................
structural formula
[2]
[Total: 13]

8
5 The halogens are a group of non-metals in Group VII of the Periodic Table.
(a) The reactivity of the halogens decreases down the group.
Describe an experiment which shows that chlorine is more reactive than iodine. Include an
equation in your answer.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(b) The halogens form interhalogen compounds. These are compounds which contain two different
halogens.
Deduce the formula of the compound which has the composition 0.013 moles of iodine atoms
and 0.065 moles of fluorine atoms.
....................................................................................................................................................
.............................................................................................................................................. [2]
(c) Iodine reacts with chlorine to form a dark brown liquid, iodine monochloride.
chlorine
supplied
crystals
of iodine
I2(s) + Cl 2(g) → 2ICl (l)

dark brown
When more chlorine is added and the tube is sealed, a reversible reaction occurs and the
reaction comes to equilibrium.
ICl (l) + Cl 2(g) ICl 3(s)

dark brown yellow
(i) Give another example of a reversible reaction.
....................................................................................................................................... [1]
(ii) Explain the term equilibrium.
.............................................................................................................................................
....................................................................................................................................... [2]
© UCLES 2015 0620/31/M/J/15

9
(d) Chlorine is removed from the tube and a new equilibrium is formed.
Explain why there is less of the yellow solid and more dark brown liquid in the new equilibrium
mixture.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(e) A sealed tube containing the equilibrium mixture is placed in ice-cold water. There is an increase
in the amount of yellow solid in the equilibrium mixture.
What can you deduce about the forward reaction in this equilibrium?
ICl (l) + Cl 2(g) ICl 3(s)
Explain your deduction.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 13]

10
6 Acid-base reactions are examples of proton transfer.
(a) Ethylamine is a weak base and sodium hydroxide is a strong base.
(i) In terms of proton transfer, explain what is meant by the term weak base.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Given aqueous solutions of both bases, describe how you could show that sodium
hydroxide is the stronger base. How could you ensure a ‘fair’ comparison between the two
solutions?
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(b) Ethylamine reacts with acids to form salts.
CH3CH2NH2 + HCl → CH3CH2NH3Cl

ethylammonium chloride
(i) Complete the equation for the reaction between sulfuric acid and ethylamine. Name the
salt formed.
......CH3CH2NH2 + ............ → .........................
name of salt ............................................................................................. [3]
(ii) Amines and their salts have similar chemical properties to ammonia and ammonium salts.
Suggest a reagent that could be used to displace the weak base, ethylamine, from its salt
ethylammonium chloride.
....................................................................................................................................... [1]
© UCLES 2015 0620/31/M/J/15

11
(c) Gases diffuse, which means that they move to occupy the total available volume.
(i) Explain, using kinetic particle theory, why gases diffuse.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) When the colourless gases hydrogen bromide and ethylamine come into contact, a white
solid is formed.
CH3CH2NH2(g) + HBr(g) → CH3CH2NH3Br(s)

white solid
The following apparatus can be used to compare the rates of diffusion of the two gases
ethylamine and hydrogen bromide.
gives off gives off

CH3CH2NH2(g) HBr(g)
A B C

ethylamine(aq) conc. hydrobromic acid
Predict at which position, A, B or C, the white solid will form. Explain your choice.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
[Total: 14]

© UCLES 2015
DATA SHEET

Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
12
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/31/M/J/15
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY


• R reject
• ( ) the word / phrase in brackets is not required, but sets the context
• ORA or reverse argument

1(a) Any two fossil fuels from: I ethane / oil / naphtha / coal / gas
crude oil / petroleum;
natural gas / methane; R coke / bitumen / lubricating oil / wood
petrol / gasoline;
kerosene / paraffin;
diesel (oil) / gas oil;
fuel oil;
refinery gas / LPG;
propane;
butane; 2
1(b) hydrogen, oxygen, nitrogen; 2 A H, O, N
All three for 2 marks I H2, O2, N2
two for 1 mark
1(c)(i) M1 oxygen and nitrogen (from air) react; A nitrogen combust for M1
R M1 if oxygen or nitrogen originate from
the fuel
M2 oxides of nitrogen OR nitrogen oxide(s) are formed; A named oxide of nitrogen e.g. nitrogen
dioxide
A correct formulae
A NOx
M3 nitrogen oxides formed react with water (to form acid); 3

1(c)(ii) Any two from: R ‘global warming / greenhouse effect’
M1 lowers pH or acidifies lakes / rivers or kills fish; R ‘increases pH of lakes so kills fish’ for M1
M2 changes composition of soils or reduces fertility of soil or reduces crop A removes nutrients / leaches the soil
yields deforestation or kills crops / trees / plants / leaves;
M3 attacks (limestone) buildings or statues; A alternative words for ‘attacks’ e.g.

damages / reacts with / corrode / erode for
M3 and M4
M4 attacks metal (structures) / bridges; 3 I rusting but A ‘enhances rusting’ for M4

I toxicity to humans
1(d) Any three from:
M1 wood burns to produce (less) carbon dioxide;
M2 trees (wood) take in carbon dioxide;
M3 by photosynthesis;
M4 wood is carbon neutral fuel;
3

2(a) M1 Forming an oxide (All) elements or (all) impurities react with

(all) elements or (all) impurities become oxides; oxygen
A M1 for any one element becoming an
oxide
M2 Gaseous oxides A formulae / carbon monoxide

carbon dioxide or sulfur (di)oxide escape / are removed as gases; A oxides of sulfur / carbon
I sulfur trioxide
M3 Acidic oxides A silicon (di)oxide for silicon(IV) oxide

silicon(IV) oxide or phosphorus(III / V) oxide react / are neutralised by calcium A phosphorus (tri/pent)oxide for
oxide / lime; phosphorus(III / V) oxide
M4 Equation mark A multiples

any one of the following equations I state symbols
S + O2 SO2; I unbalanced equations
C + O2 CO2 or 2C + O2 2CO; R other combustion equations with
Si + O2 SiO2; incorrect species
4P + 5O2 2P2O5 or P4 + 5O2 2P2O5;
4P + 3O2 2P2O3 or P4 + 3O2 2P2O3;
M5 Word equation mark A calcium oxide + silicon(IV) oxide slag

any one of the following word equations A correct symbol equation for M5 but
calcium oxide + silicon(IV) oxide calcium silicate; R other equations with incorrect species
calcium oxide + phosphorus(III / V) oxide calcium phosphate; 5 used as M5

2(b)(i) Any one from: A bridges

(making) car (bodies); A tools
machinery; I cutlery
chains;
pylons;
white goods;
nails;
screws;
as a building material;
sheds / roofs;
reinforcing concrete; 1
2(b)(ii) Any one from: I cutlery items
knives; I bridges
drills;
railway tracks;
machine / cutting tools / hammers;
razor blades;
chisels; 1
2(b)(iii) M1 atoms or cations or (positive) ions or metal ions; I (sea of) electrons
R protons or nuclei for M1
M2 arranged in a lattice or in layers or in rows or in a regular structure; A M2 non-directional forces
M3 rows or layers slide over one another; 3 A ECF on particle named in M1 for M3
I ‘atoms’ slide over one another
2(b)(iv) M1 carbon atoms or particles in structure different size (to cations); R ions and molecules for M1
M2 so reduce moving or interrupt movement; 2 A M2 for prevents sliding

A M2 for ‘stops’ sliding
3(a)(i) Zn to Zn2+ ;
because electron loss; 2 A because oxidation number has
increased for M2

3(a)(ii) (2)H+ or ‘hydrogen ion(s)’; R H2 or ‘hydrogen’
it accepts electrons or takes electrons (from zinc atoms); 2 A because it is reduced or because it
decreases in oxidation number
A it causes zinc to lose electrons
3(b)(i) zinc displaces copper or zinc more reactive than copper; A copper less reactive than zinc
I zinc reacts with copper ions or with Cu2+
or with copper chloride
I zinc reacts with copper
I Cu2+ ions are reduced
Zn + CuCl2 → ZnCl2 + Cu A multiples

OR Zn + Cu2+ Cu + Zn2+ ; 2 I state symbols
3(b)(ii) steeper (line) or higher gradient;
(means an) increased rate; A less time to complete the reaction / same
amount of gas in less time / faster reaction /
more gas in the same time period
but the same (final) volume; A same volume of hydrogen produced

A ‘amount’ for volume
3 A no extra gas is made
3(c) M1 less steep (line) or lower gradient; A alternative phrases e.g. ‘shallower’
M2 (because of) decreased rate; A more time to complete the reaction

A same amount of gas in more time
A slower rate or slower reaction
M3 ethanoic is a weak(er) acid; ORA
M4 only partially ionised or dissociated A not fully dissociated or ionised

OR lower concentration of hydrogen ions; 4 A ionises less (than HCl)
I less hydrogen ions

3(d) M1 moles of HCl = 0.1 (mol);
M2 moles of Zn = 0.05 (mol); A ECF for M1 × ½
mass of zinc = 3.25 g; 3 A ECF for M2 × 65

Unit required for M3
4(a)(i) Any three from:
contain the same functional group;
common methods of preparation;
same or similar chemical properties;
physical properties vary in a predictable manner / show trends / show a I different physical properties / physical
gradual change / an example of a physical variation e.g. mpt, bpt volatility properties change / an unqualified or slight
viscosity; 3 change
R same or similar physical properties
4(a)(ii) propanol / propan-1-ol / propan-2-ol; 1
4(a)(iii) if molecular formula is given as C10H22O award 2 marks A C10H21OH for two marks
if not, look for evidence of some correct working for one mark 2 A (10 × 12) + (22 × 1) + 16 = 158 for one
158 – 17 = 141 (working) mark
OR
12n + 2n + 1 = 141
OR
n = 10
4(b) they have the same molecular formula (C4H10O); A same number of each type of atom
I same number of atoms
different structures; 2 A different structural formula or different

arrangement of atoms

4(c)(i) M1 butene or but-1-ene; M1 and M2 are independent

A but-2-ene for M1
M2 structural formula of but-1-ene; 2 Minimum acceptable structure is

CH3CH2CH=CH2
Double bond must be shown
R structure of but-2-ene for M2
4(c)(ii) butyl ethanoate; 1 A butanyl
R ethenoate and ethanoic
4(c)(iii) butanoic acid; A butyric acid
structural formula of butanoic acid; 2 Minimum acceptable structure is
CH3CH2CH2CO2H
A CH3CH2CH2COOH with C–HO
connectivity in acid group
5(a) M1 add chlorine to (potassium) iodide solution; Solution must be implied for M1
A any soluble iodide solution
M2 red / brown / yellow / orange (solution) is formed; A black (ppt or solid)
M3 A multiples
Cl2 + 2KI 2KCl + I2 I state symbols but KI(aq) would allow the
Cl2 + 2I– 2Cl – + I2 ; 3 solution aspect of mark in M1
5(b) M1 (0.013 moles of I and 0.065 moles of F atoms gives a) ratio 1:5; Award 2 marks for IF5
Formula = IF5 ; 2 A one mark for I5F (as ratio is inverted)

A one mark for IFl5 or I5Fl

5(c)(i) example of a reversible reaction including attempts at removing / adding A written description of the reaction e.g.
waters of crystallisation ‘Haber process’ unless equation is
OR example of a reaction which under closed conditions would be reversible; 1 attempted in which case ignore written
description
A word equations / unbalanced equations
A equations without equilibrium arrows
I descriptions of physical changes
5(c)(ii) Any two from: I reference to ‘closed system’
(a reaction)
M1 which can take place in both directions OR which can be approached A ‘a reaction which can go forwards and
from both directions; backwards’ for M1
I ‘a reaction with an equilibrium arrow’ or
with ‘⇌’ for M1
M2 in which concentrations / macroscopic properties do not change (with R concentrations (of reactants and
time); products) are the same
M3 the two reaction rates are equal; 2

5(d) M1 equilibrium goes to LHS OR equilibrium goes to reactants side; A reaction goes to LHS but
R ‘equilibrium goes to LHS and to
products side’
A backward reaction is favoured
I less yield or less products
M2 because the concentration of chlorine decreases; 2 A ‘reactant’ for ‘chlorine’ but not reactants
A to replace missing chlorine

5(e) M1 equilibrium goes to RHS OR equilibrium goes to products side; A reaction goes to RHS but
R ‘equilibrium goes to RHS and to
reactants side’
A forward reaction is favoured
I more yield or more products
M2 exothermic reactions are favoured by low temperatures; A for M1 and M2 ‘decreasing temperature
makes the equilibrium go to RHS’
M3 the forward reaction is exothermic; 3 A backward reaction is endothermic

6(a)(i) M1 proton acceptor; A alternative words to ‘acceptor’ e.g.

‘receiver’
I references to pH
M2 does not accept (protons) readily A ‘hydrogen ion’ or ‘H+’ for proton
OR less able to accept protons (than strong bases); 2 I accepts fewer / less protons
6(a)(ii) M1 same concentration of both bases;
M2 measure their pH; A suitable method e.g. universal indicator

or pH paper or pH meter
I litmus or methyl orange or
phenolphthalein
I titration methods for M2 and M3
M3 the higher pH is the stronger base; 3 A suitable colours of both weak strong
bases e.g. ethylamine is (greeny)blue,
NaOH is darker blue / purple
A alternative methods for M2 and M3

e.g. measure conductivity (M2) and higher
conductivity is the stronger base (M3)
e.g.add aluminium / Al (M2) and stronger
base gives faster rate of
effervescence / more fizzing / more
bubbling (M3)
6(b)(i) 2CH3CH2NH2 + H2SO4 → (CH3CH2NH3 )2 SO4 A multiples
species; I state symbols
balancing; A one mark for correct product
the salt is ethylammonium sulfate; 3 A close spellings

A diethylammonium sulfate

6(b)(ii) sodium hydroxide / calcium hydroxide / NaOH / Ca(OH)2 ; 1 A any Group 1 or Group 2 hydroxide or
oxide
6(c)(i) Any two from:
(particles move in) random motion;
(particles) collide; A alternative phrases for collide
(particles) move from a region of high concentration to low concentration; 2 A down a concentration gradient
6(c)(ii) C;
M2 it has a lower (relative) molecular mass (than HBr); A ethylamine is less dense
A ethylamine is a lighter molecule but
M3 ethylamine diffuses faster (than HBr); I ‘ethylamine is lighter’
3 I ethylamine is a smaller molecule
A ethylamine molecules or particles
move faster
A ECF for M2 and M3 if A is given e.g.

HBr diffuses faster for M3 because it is a
lighter molecule for M2
A ECF for M2 if B is given e.g. they diffuse
at same rate for M3 because molecules
weigh the same for M2

CHEMISTRY 0620/51
*9170745782*
where relevant.
by phone: +44 1223 553554,
by fax: +44 1223 553558,
IB15 06_0620_51CI/3RP
2
For Question 1
(a) 50 cm3 measuring cylinder
(b) stirring thermometer, 0–110 °C
(c) polystyrene cup and 250 cm3 beaker
[C] (d) 150 cm3 of aqueous sodium hydroxide, NaOH, of concentration 1.0 mol / dm3, labelled aqueous
sodium hydroxide for question 1
[H] (e) 100 cm3 of aqueous hydrochloric acid, HCl, of concentration 2.0 mol / dm3, labelled acid A
[C] (f) 100 cm3 of aqueous sulfuric acid, H2SO4, of concentration 2.0 mol / dm3, labelled acid B
(h) 50 cm3 burette with stand and clamp
(i) teat pipette
(j) funnel for filling burette
© UCLES 2015 0620/51/CI/M/J/15

3
For Question 2
(a) 0.5 g of aluminium ammonium sulfate (ammonium alum), Al NH4(SO4)2.12H2O, in a

stoppered tube, labelled solid C
(b) pH indicator papers and chart
(c) rack of six test-tubes, including one hard-glass test-tube
(d) access to water and distilled water
(e) aqueous barium nitrate of concentration suitable to give a positive test for sulfate ions
[C] (f) aqueous nitric acid of concentration 0.5 mol / dm3
[C] (g) aqueous sodium hydroxide of concentration 1.0 mol / dm3
(h) aqueous ammonia of concentration 1.0 mol / dm3
[N][H] (i) aqueous silver nitrate of concentration suitable to give a positive halide test
(j) spatula
(k) 10 cm3 measuring cylinder
(l) Bunsen burner and matches
(m) test-tube holder
(n) teat pipettes
(o) splints

4
© UCLES 2015 0620/51/CI/M/J/15

5

6
© UCLES 2015 0620/51/CI/M/J/15

7
JUNE 2015
penalised.
© UCLES 2015 0620/51/CI/M/J/15

[Turn over
8
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable
effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will
be pleased to make amends at the earliest possible opportunity.
© UCLES 2015 0620/51/CI/M/J/15

*7727926786*
CHEMISTRY 0620/51
1 hour 15 minutes

Total
IB15 06_0620_51/3RP
2
1 You are going to investigate what happens when aqueous sodium hydroxide reacts with aqueous
solutions of two different acids, A and B.
Instructions
(a) Experiment 1
Use a measuring cylinder to pour 50 cm3 of aqueous sodium hydroxide into the polystyrene
cup provided. Put the cup into a 250 cm3 beaker for support. Measure the initial temperature of
the solution and record it in the table below.
Fill the burette with the solution of acid A provided to the 0.0 cm3 mark.
Add 5.0 cm3 of acid A to the aqueous sodium hydroxide in the cup and stir the mixture.
Measure and record the maximum temperature of the solution in the table below. Add a further
5.0 cm3 of acid A to the cup and stir the mixture. Measure and record the temperature of the
mixture in the table below.
Continue to add 5.0 cm3 portions of acid A to the cup, until a total volume of 40 cm3 of acid has
been added. Stir after each addition and measure and record the temperatures in the table.
At the end of this experiment, pour the solution away and rinse the polystyrene cup.
temperature of solution
volume of acid A added / cm3
in polystyrene cup / °C
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
[3]
© UCLES 2015 0620/51/M/J/15

3
(b) Experiment 2
Empty the burette and rinse it with distilled water. Half fill the burette with the solution of acid B
and swirl the contents. Discard this acid.
Now fill the burette to the 0.0 cm3 mark with the solution of acid B.
Repeat Experiment 1 using acid B instead of acid A.

Record your results in the table below.
temperature of solution
volume of acid B added / cm3
in polystyrene cup / °C
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
[3]

4
(c) Plot the results for Experiments 1 and 2 on the grid and draw a smooth line graph for each
experiment.
Clearly label your graphs.
50
40
temperature
of solution
/ °C
30
20
10
0 5 10 15 20 25 30 35 40
volume of acid added / cm3
[5]
(d) Use your graph to estimate the temperature of the reaction mixture when 8 cm3 of acid B were
added to 50 cm3 of aqueous sodium hydroxide.
.............................................................................................................................................. [2]
© UCLES 2015 0620/51/M/J/15

5
(e) What type of chemical reaction, other than neutralisation, occurs when acid A reacts with
sodium hydroxide?
.............................................................................................................................................. [1]
(f) Why was the burette rinsed firstly with distilled water and then with acid B before starting
Experiment 2?
....................................................................................................................................................
.............................................................................................................................................. [2]
(g) The solutions of acids A and B are the same concentration.
(i) In which experiment is the maximum temperature change greater?
....................................................................................................................................... [1]
(ii) Suggest why the maximum temperature change is greater in this experiment.
.............................................................................................................................................
....................................................................................................................................... [1]
(h) Describe one source of error in Experiment 2. Suggest an improvement to reduce this source
of error.
source of error ...........................................................................................................................
improvement ........................................................................................................................ [2]
[Total: 20]

6
2 You are provided with solid C, which is a salt containing two cations and one anion.
Carry out the following tests on solid C recording all of your observations in the table.
tests observations
tests on solid C
(a) Describe the appearance of solid C. ................................................................ [1]
(b) Use a spatula to put a little of solid C into a

hard-glass test-tube. Heat the solid gently ......................................................................
and then strongly.
......................................................................
Test any gases given off with damp pH
indicator paper. ................................................................ [3]
tests on a solution of C
Add about 10 cm3 of distilled water to the rest of

solid C, stopper and shake to dissolve.
Divide the solution into four equal portions in
four test-tubes. Carry out the following tests.
(c) To the first portion of the solution, add

aqueous sodium hydroxide using a teat
pipette. ................................................................ [2]
Now add excess aqueous sodium

hydroxide to the mixture. ................................................................ [1]
Heat the mixture gently and test any gases ......................................................................

given off.
................................................................ [2]
(d) To the second portion of the solution, add ......................................................................

excess aqueous ammonia.
................................................................ [2]
(e) To the third portion of the solution, add a

few drops of dilute nitric acid and about
1 cm3 of aqueous silver nitrate. ................................................................ [1]
(f) To the fourth portion of the solution, add ......................................................................

a few drops of dilute nitric acid and about
1 cm3 of barium nitrate solution. ................................................................ [2]
© UCLES 2015 0620/51/M/J/15

7
(g) What does test (b) tell you about the nature of solid C?
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(h) What does test (e) tell you about the nature of solid C?
.............................................................................................................................................. [1]
(i) What conclusions can you draw about the identity of solid C?
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 20]

8
Test for anions

produced

aluminium (Al 3+)
Test for gases

© UCLES 2015 0620/51/M/J/15

0620 CHEMISTRY


• R reject
• ( ) the word/phrase in brackets is not required, but sets the context
• ora or reverse argument

Question Answer Marks Additional Guidance
1(a) initial temperature box completed;

other temperature boxes completed; Temperatures should increase to a
trend in temperatures is comparable to Supervisor’s results; 3 maximum then decrease
1(b) initial temperature box completed;
other temperature boxes completed; Temperatures should increase to a
trend in temperatures is comparable to Supervisor’s results; 3 maximum then decrease
1(c) all 18 points plotted within half a small square = 3 marks
17 points plotted within half a small square = 2 marks
16 points plotted within half a small square = 1 mark;
best fit smooth line / intersecting straight lines;
labels; 5
1(d) value read from graph; 2
indication clearly shown;
1(e) exothermic; 1
1(f) to remove traces of acid A / clean;
to remove water; 2
1(g)(i) experiment 2 / acid B; 1
1(g)(ii) acid B is stronger / dibasic / has a lower pH / more acidic; 1 I more reactive / more concentrated
1(h) heat losses / using a measuring cylinder / thermometer / cup not washed; I repeat and average
insulate / use burette / digital thermometer / new cup; 2

Question Answer Marks Additional Guidance
2(a) white (crystals); 1 A colourless

R precipitate
2(b) melts / liquefies / bubbles / dissolves; A reference to smell
steam / condensation / drops of liquid; I sublimation
pH 7–14; 3 A colour: green / blue / purple
I ammonia
2(c) white;
precipitate;
dissolves / clears;
pungent gas;
pH paper green / blue / purple, pH>7; 5
2(d) white;
precipitate; 2
2(e) no reaction / no change / no precipitate / nothing; 1
2(f) white;
precipitate; 2
2(g) alkaline gas / ammonia;
hydrated / water; 2
2(h) not a halide / not a named halide; 1
2(i) ammonium / NH4+ ;
3+
aluminium / Al ;
sulfate / SO42– ; 3

*9821411450*
CHEMISTRY 0620/61
1 hour
MODIFIED LANGUAGE

IB15 06_0620_61/RP
2
1 Ethanol was reacted with hot acidified potassium manganate(VII) solution using the apparatus
below. Ethanoic acid was formed.
condenser
ethanol +
electric acidified potassium
heater
manganate(VII)
(a) (i) Complete the box to identify the piece of apparatus labelled. [1]
(ii) Label the arrows. [1]
(b) (i) Suggest and explain why an electric heater is used to heat this reaction and not a
Bunsen burner.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Suggest why a condenser is necessary.
....................................................................................................................................... [1]
(c) Complete the table to show the difference in smell between ethanol and ethanoic acid.
smell
ethanol
ethanoic acid
[2]
[Total: 7]
© UCLES 2015 0620/61/M/J/15

3
2 Electricity was passed through molten lead(II) bromide using the apparatus shown.
light bulb
electrodes
molten lead(II) bromide
The formation of a brown gas was observed at the positive electrode.
(a) Give one other expected observation.
.............................................................................................................................................. [1]
(b) (i) Name a non-metal that could be used for the electrodes.
....................................................................................................................................... [1]
(ii) Suggest why iron is not used for the electrodes.
....................................................................................................................................... [1]
(c) (i) Name the brown gas formed.
....................................................................................................................................... [1]
(ii) Suggest the result of testing this gas with damp blue litmus paper.
....................................................................................................................................... [1]
(d) Name the product formed at the negative electrode.
.............................................................................................................................................. [1]
(e) State one safety precaution that should be used when doing this experiment.
.............................................................................................................................................. [1]
[Total: 7]

4
3 A mixture of coloured dyes, M, was separated by chromatography. The dyes were insoluble in
water.
The chromatogram below shows the result of separating the mixture and the chromatography of
three known dyes 1, 2 and 3.
1 2 3 M
known dyes
(a) On the diagram, label the base line (origin). [1]
(b) Name a solvent that could be used in this separation.
.............................................................................................................................................. [1]
(c) How many dyes were there in the mixture, M?
.............................................................................................................................................. [1]
(d) What are your conclusions about the identity of the dyes in the mixture, M?
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(e) How could the reliability of the results be checked?
.............................................................................................................................................. [1]
[Total: 7]
© UCLES 2015 0620/61/M/J/15

5
4 A student investigated the reaction of aqueous sodium hydroxide with aqueous solutions of two
different acids, A and B.
Two experiments were done.
(a) Experiment 1
Using a measuring cylinder, 50 cm3 of aqueous sodium hydroxide solution was poured into a
polystyrene cup. The initial temperature of the solution was measured.
A burette was filled with the solution of acid A to the 0.0 cm3 mark.
5.0 cm3 of acid A was added to the aqueous sodium hydroxide in the cup and the mixture
stirred.
The temperature of the solution was measured. Another 5.0 cm3 of acid A was added to the
cup and the mixture stirred. The temperature of the mixture was measured.
More 5.0 cm3 portions of acid A were added to the cup until a total volume of 40.0 cm3 of acid
had been added. After each addition, the mixture was stirred and the temperature measured.

6
Use the thermometer diagrams in the table to record the temperatures.
volume of acid A thermometer temperature of solution

added / cm3 diagram in polystyrene cup / °C
30
0.0 25
20
30
5.0 25
20
35
10.0 30
25
35
15.0 30
25
35
20.0 30
25
40
25.0 35
30
40
30.0 35
30
40
35.0 35
30
40
40.0 35
30
[3]
© UCLES 2015 0620/61/M/J/15

7
The burette was emptied and rinsed with distilled water, and then with acid B. This acid was
discarded. The burette was then filled up to the 0.0 cm3 mark with acid B.
(b) Experiment 2
Experiment 1 was repeated using acid B instead of acid A.

Use the thermometer diagrams in the table to record the temperatures.
volume of acid B thermometer temperature of solution

added / cm3 diagram in polystyrene cup / °C
30
0.0 25
20
40
5.0 35
30
45
10.0 40
35
45
15.0 40
35
40
20.0 35
30
40
25.0 35
30
40
30.0 35
30
40
35.0 35
30
40
40.0 35
30
[3]

8
(c) Plot the results for Experiments 1 and 2 on the grid and draw a smooth line graph for each
experiment.
50
temperature of solution / °C
40
30
20
0 10 20 30 40
volume of acid added / cm3
[5]
(d) Use your graph to estimate the temperature of the reaction mixture when 8.0 cm3 of acid B
were added to 50 cm3 of aqueous sodium hydroxide.
.............................................................................................................................................. [2]
(e) What type of chemical reaction, other than neutralisation, occurred when acid A reacted with
sodium hydroxide?
.............................................................................................................................................. [1]
© UCLES 2015 0620/61/M/J/15

9
(f) Why was the burette rinsed firstly with distilled water and then with acid B before starting
Experiment 2?
....................................................................................................................................................
.............................................................................................................................................. [2]
(g) The solutions of acids A and B are the same concentration.
(i) In which experiment was the maximum temperature change greater?
....................................................................................................................................... [1]
(ii) Suggest why the maximum temperature change was greater in this experiment.
.............................................................................................................................................
....................................................................................................................................... [1]
(h) Describe one source of error in Experiment 2. Suggest one improvement to reduce this
source of error.
source of error ...........................................................................................................................
improvement ..............................................................................................................................
[2]
[Total: 20]

10
5 Solid C was analysed. Solid C was a mixture of salts containing aluminium ions, sulfate ions and
another cation (positive ion).
Tests on solid C, and some of the observations, are in the table.
tests observations
tests on solid C
(a) Appearance of solid C. white solid
(b) A little of solid C was heated gently

and then strongly. condensation was formed at the top of the test-tube
The gas given off was tested with

damp pH indicator paper. pungent gas, pH = 10
tests on a solution of C
Water was added to solid C to produce

an aqueous solution, solution C.
(c) Drops of aqueous sodium

hydroxide were added to solution C
using a teat pipette. ............................................................................................
Excess aqueous sodium hydroxide

was then added to the mixture. ...................................................................................... [3]
The mixture was boiled gently and

any gases given off were tested. pungent gas, pH = 10
(d) Excess aqueous ammonia was

added to solution C. ...................................................................................... [1]
(e) A few drops of dilute nitric acid and

aqueous silver nitrate were added
to solution C. ...................................................................................... [1]
(f) A few drops of dilute nitric acid and

barium nitrate solution were added
to solution C. ...................................................................................... [2]
© UCLES 2015 0620/61/M/J/15

11
(g) What does the formation of condensation in test (b) tell you about the nature of solid C?
.............................................................................................................................................. [1]
(h) What does test (e) tell you about the nature of solid C?
.............................................................................................................................................. [1]
(i) (i) Name the gas given off in test (b).
....................................................................................................................................... [1]
(ii) What is your conclusion about the identity of the other cation in solid C?
....................................................................................................................................... [1]
[Total: 11]

12
6 A catalyst is a substance that speeds up the rate of a chemical reaction and remains unchanged
at the end of the reaction.
Hydrogen peroxide solution, H2O2, breaks down to form oxygen. This decomposition is very slow
if a catalyst is not used.
Plan an investigation to show that copper(II) oxide is a suitable catalyst for this reaction.
You can use aqueous hydrogen peroxide and common laboratory apparatus.
Step 1 Show that copper(II) oxide catalyses the decomposition of hydrogen peroxide and
measure the rate of the reaction.
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
Step 2 Show that the copper(II) oxide is unchanged at the end of the decomposition.
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
[Total: 8]
© UCLES 2015 0620/61/M/J/15

0620 CHEMISTRY


• R reject
• ( ) the word/phrase in brackets is not required, but sets the context

1(a)(i) flask; 1
1(a)(ii) top arrow water and bottom arrow water; 1
1(b)(i) to prevent fire / ref. to safety / controlled heating; I dangerous
ethanol is flammable; 2
1(b)(ii) to prevent evaporation / loss of reactants or ethanol; 1
1(c) ethanol: sweet / nail varnish remover / alcohol / spirit;
ethanoic acid: vinegar / sour / acid / sharp / pungent; 2 I strong / pleasant
2(a) bulb lights / silver-grey liquid or solid forms / bubbles; 1

2(b)(i) carbon / graphite; 1
2(b)(ii) it reacts / is reactive; 1 A corrodes / rusts
I dissolves
2(c)(i) bromine / Br2; 1 R bromide
2(c)(ii) bleaches / turns white; 1
2(d) lead; 1 R lead(II) / lead ions
2(e) fume cupboard / well-ventilated area; 1 I references to goggles / safety clothing

3(a) base line / origin clearly labelled on diagram; 1

3(b) any organic solvent / ethanol / alcohol / acetone; 1 R water / acids
3(c) 3; 1
3(d) 1 and 3 present; I reference to properties of dyes 1, 2 and 3
2 not present;
unknown dye present; 3
3(e) repeat the experiment / use a different solvent / measure Rf values; 1
4(a) 25, 27, 30, 32, 34, 36, 35, 34, 33 please put an ‘x’ by any incorrectly plotted
all 9 = 3 marks points
8 = 2 marks
7 = 1 mark 3
4(b) 25, 34, 41, 40, 39, 38, 37, 36, 34
all 9 = 3 marks
8 = 2 marks
7 = 1 mark 3
4(c) all 18 points plotted within half a small square = 3 marks
17 points plotted within half a small square = 2 marks
16 points plotted within half a small square = 1 mark;
smooth line graph;
labels; 5
4(d) value read from graph, 38.5 °C;
indication clearly shown; 2
4(e) exothermic; 1

4(f) to remove traces of acid A / clean;

to remove water; 2
4(g)(i) experiment 2 / acid B; 1
4(g)(ii) acid B is stronger / dibasic / has a lower pH / more acidic; 1 I more reactive / more concentrated
4(h) heat losses / using a measuring cylinder / thermometer / cup not washed; I repeat and average
insulate / use burette / digital thermom. / new cup; 2
5(c) white;
precipitate;
dissolves / clears; 3
5(d) white precipitate; 1
5(e) no reaction / no change / no precipitate / colourless solution; 1
5(f) white;
precipitate; 2
5(g) hydrated / water; 1
5(h) not a halide / not a named halide; 1
5(i)(i) ammonia / NH3; 1
5(i)(ii) ammonium / NH4+; 1

6 step 1
add copper oxide or catalyst to hydrogen peroxide;
measure volume of gas / mass loss / collect gas / count bubbles;
over time;
known volume of hydrogen peroxide;
compare to hydrogen peroxide on its own;
test gas with glowing splint;
splint relights;
step 2
filter copper(II) oxide;
dry;
weigh;
compare to original mass;
OR
filter (copper(II) oxide) / evaporate to dryness;
add to hydrogen peroxide;
measure rate of reaction;
compare to first experiment; max 8

CHEMISTRY 0620/11
45 Minutes
Soft clean eraser
*0290816641*

IB15 11_0620_11/5RP
2
1 Diagrams X, Y and Z represent the three states of matter.
X Y Z
Which change occurs during boiling?
A X to Y B Y to Z C Z to X D Z to Y
2 P, Q, R and S are pieces of apparatus.
P Q R S
50 cm3 25 cm3
3 3
100 cm 50 cm
Which row describes the correct apparatus for the measurement made?
apparatus measurement made
A P the volume of acid added to alkali in a titration

B Q 1 cm3 of acid to add to calcium carbonate in a rate-determining experiment
C R 75 cm3 of a gas given off in a rate-determining experiment
D S 20 cm3 of alkali for use in a titration
3 Which statement about atoms is correct?
A Atoms contain protons and electrons in the nucleus.

B Neutrons are negatively charged.
C Protons are positively charged.
D The nucleon number is the number of neutrons.
© UCLES 2015 0620/11/O/N/15

3
4 Which diagram correctly shows the ions present in the compound potassium fluoride?
–
+ e e
e e e e
e e
e e e e e e
A K+ e e e e e e F–
key
e e
e e e e = nucleus
e e
e = electron
+
– e e
e e e e
e e
e e e e e e
B K– e e e e e e F+
e e
e e e e
e e
e e + –
e e e e
e e
e e e e e e
C K+ e e e e e e F–
e e
e e e e
e e
–
e e +
e e e e
e e
e e e e e e
D K– e e e e e e F+
e e
e e e e
e e

4
5 What do the nuclei of 11H hydrogen atoms contain?
A electrons and neutrons

B electrons and protons
C neutrons only
D protons only
6 The electronic structures of atoms X and Y are shown.
X Y
X and Y form a covalent compound.
What is its formula?
A XY5 B XY3 C XY D X3Y
7 Two atoms of magnesium, Mg, react with one molecule of oxygen, O2.
What is the formula of the product?
A MgO B MgO2 C Mg2O D Mg2O2
8 Which row describes the electrolysis of molten potassium bromide?
product at anode product at cathode
A bromine hydrogen
B bromine potassium
C hydrogen bromine
D potassium bromine
© UCLES 2015 0620/11/O/N/15

5
9 The diagram shows a section of an overhead power cable.
steel
ceramic
aluminium
Which statement explains why a particular substance is used?
A Aluminium has a low density and is a good conductor of electricity.

B Ceramic is a good conductor of electricity.
C Steel can rust in damp air.
D Steel is more dense than aluminium.
10 Which reaction is endothermic?
A acid neutralising alkali causing a temperature increase

B adding magnesium to hydrochloric acid
C calcium carbonate decomposing when heated
D combustion of fossil fuels

6
11 Solid hydrated sodium carbonate was added to solid citric acid.
The mixture was stirred and the temperature recorded every 10 seconds.
The results are shown on the graph:
25
20
15
temperature
/ °C
10
0
0 20 40 60 80 100
time / s
Which row describes the reaction?
reaction type energy change
A neutralisation endothermic
B neutralisation exothermic
C thermal decomposition endothermic
D thermal decomposition exothermic
12 The effect of temperature on the rate of the reaction between marble chips and hydrochloric acid
can be investigated by measuring the production of carbon dioxide.
Which item of equipment is not required for the investigation?
A condenser
B gas syringe
C stopclock
D thermometer
© UCLES 2015 0620/11/O/N/15

7
13 The element vanadium, V, forms several oxides.
In which change is oxidation taking place?
A VO2 → V2O3
B V2O5 → VO2
C V2O3 → VO
D V2O3 → V2O5
14 Some crystals of hydrated cobalt(II) chloride are heated in a test-tube until no further change is
observed.
The test-tube is allowed to cool and a few drops of water are then added to the contents.
Which colours are observed?
before after after adding

heating heating water
A blue pink blue

B blue white blue
C pink blue pink
D white blue white
15 The diagram shows a simplified form of the Periodic Table:
W X
Y
Which elements will form an acidic oxide?
A W and Z B W only C X and Y only D Y only

8
16 A white solid is insoluble in water.
When it is added to hydrochloric acid, bubbles of gas are formed.
Adding aqueous ammonia to the solution formed gives a white precipitate. Adding excess
aqueous ammonia causes the precipitate to re-dissolve.
What is the white solid?
A aluminium nitrate
B ammonium nitrate
C calcium carbonate
D zinc carbonate
17 Which property is not characteristic of a base?
A It reacts with a carbonate to form carbon dioxide.

B It reacts with an acid to form a salt.
C It reacts with an ammonium salt to form ammonia.
D It turns universal indicator paper blue.
18 Four stages in the preparation of a salt from an acid and a solid metal oxide are listed.
1 Add excess solid.

2 Evaporate half the solution and leave to cool.
3 Filter to remove unwanted solid.
4 Heat the acid.
In which order should the stages be carried out?
A 1→3→4→2
B 2→1→3→4
C 4→1→3→2
D 4→2→1→3
© UCLES 2015 0620/11/O/N/15

9
19 Which statements about Group I and Group VII elements are correct?
1 In Group I, lithium is more reactive than potassium.

2 In Group VII, chlorine is more reactive than fluorine.
statement 1 statement 2
A
B
C
D
20 The Periodic Table lists all the known elements.
Elements are arranged in order of ....... 1 ....... number.
The melting points of Group I elements ....... 2 ....... down the group.
The melting points of Group VII elements ....... 3 ....... down the group.
Which words correctly complete the gaps 1, 2 and 3?
1 2 3
A nucleon decrease increase

B nucleon increase decrease
C proton decrease increase
D proton increase decrease
21 The table gives information about four elements.
Which element is a transition metal?
electrical density in melting point

conductivity g / cm3 in °C
A good 0.97 98
B good 7.86 1535
C poor 2.33 1410
D poor 3.12 –7

10
22 The Group 0 elements are unreactive.
The gas used to fill balloons is ....... X....... .
This gas is unreactive because it has ....... Y....... electrons in its outermost shell.
Which words correctly complete gaps X and Y?
X Y
A argon eight
B argon two
C helium eight
D helium two
23 Which diagram shows the structure of an alloy?
A B
– + –
+ – +
– + –
+ – +
– + –
+ – +
– + –
+ – +
– + –
C D
© UCLES 2015 0620/11/O/N/15

11
24 The diagrams show what happens when three different metals are added to water.
bubbles flame
of gas
X Y Z
What are X, Y and Z?
X Y Z
A calcium copper potassium

B copper calcium potassium
C potassium calcium copper
D potassium copper calcium
25 Which metal would be suitable for all of the following uses?
• making aircraft bodies
• making food containers
• making overhead power cables
A aluminium
B brass
C mild steel
D pure iron
26 Iron is extracted from its ore (hematite) in the blast furnace.
Which gas is produced as a waste product?
A carbon dioxide
B hydrogen
C nitrogen
D oxygen

12
27 Which statements about water are correct?
1 Household water may contain salts in solution.
2 Water for household use is filtered to remove soluble impurities.
3 Water is treated with chlorine to kill bacteria.
4 Water is used in industry for cooling.
A 1, 2, 3 and 4
B 1, 2 and 3 only
C 1, 3 and 4 only
D 2, 3 and 4 only
28 Which is a use of oxygen?
A as the gas in a lamp

B to react with ethene to form ethanol
C to react with methane in a Bunsen burner
D to react with hematite to form iron
29 Carbon monoxide is an air pollutant produced when petrol is burned in a car engine.
Why is carbon monoxide considered to be an air pollutant?
A It causes climate change.

B It causes the corrosion of buildings.
C It is a significant greenhouse gas.
D It is poisonous.
30 Fertilisers are mixtures of different compounds used to increase the growth of crops.
Which pair of substances contains the three essential elements for plant growth?
A ammonium nitrate and calcium phosphate

B ammonium nitrate and potassium chloride
C ammonium phosphate and potassium chloride
D potassium nitrate and calcium carbonate
© UCLES 2015 0620/11/O/N/15

13
31 Which process does not produce carbon dioxide?
A complete combustion of a fossil fuel

B fermentation
C reaction of an alkali with a carbonate
D respiration
32 The apparatus shown is set up and left for a week.
damp iron wool
air
water
Which diagram shows the level of the water at the end of the week?
A B C D
33 Carbon dioxide and methane both contribute to climate change.
Which process produces both gases?
A complete combustion of natural gas

B farming cattle
C heating calcium carbonate
D respiration

14
34 A student is asked to draw a diagram showing the uses of limestone.
making
making lime
cement
1 2
limestone
added, with hematite,

to a blast furnace
Which numbered lines show a correct use of limestone?
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
35 The diagram shows the structure of a simple hydrocarbon and the products of two of its
reactions.
1 2 3
H H H H H H
bromine steam
Br C C Br C C H C C O H
H H H H H H
dibromoethane ethane ethanol
Which structures are named correctly?
structure
1 2 3
A
B
C
D
© UCLES 2015 0620/11/O/N/15

15
36 Which row describes the formation of a polymer?
monomer polymer
A ethane poly(ethane)
B ethane poly(ethene)
C ethene poly(ethane)
D ethene poly(ethene)
37 What is not the correct use for the fraction named?
name of fraction use
A fuel oil making waxes

B gas oil diesel engines
C kerosene jet fuel
D naphtha fraction making chemicals
38 Ethanol can be formed by
1 fermentation
2 reaction between steam and ethene
Which of these processes uses a catalyst?
1 2
A
B
C
D

16
39 Which homologous series is not represented in the compounds shown below?
H H H H H H
H C C C H H C C C H
H H H H O H H
H H H H H
H C C C O H H C C C H
H H O H H C H H
A alcohols
B alkanes
C alkenes
D carboxylic acids
40 Alkenes are manufactured by cracking hydrocarbons obtained from petroleum.
hydrocarbon P obtained cracking

hydrocarbon Q
from petroleum
Which row describes the size of the molecules in hydrocarbons P and Q and the effect of Q on
aqueous bromine?
size of P size of Q effect of Q

molecules molecules on aqueous bromine
A large small decolourises

B large small no effect
C small large decolourises
D small large no effect
© UCLES 2015 0620/11/O/N/15

17
BLANK PAGE
© UCLES 2015 0620/11/O/N/15

18
BLANK PAGE
© UCLES 2015 0620/11/O/N/15

19
BLANK PAGE
© UCLES 2015 0620/11/O/N/15

© UCLES 2015
DATA SHEET
Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20

Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
20
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/11/O/N/15
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY
Cambridge is publishing the mark schemes for the October/November 2015 series for most

Question Question
Key Key
Number Number
1 B 21 B
2 A 22 D
3 C 23 C
4 C 24 A
5 D 25 A
6 D 26 A
7 A 27 C
8 B 28 C
9 A 29 D
10 C 30 C
11 A 31 C
12 A 32 B
13 D 33 B
14 C 34 A
15 D 35 B
16 D 36 D
17 A 37 A
18 C 38 A
19 D 39 C
20 C 40 A

*9575812330*
CHEMISTRY 0620/21


1 hour 15 minutes

IB15 11_0620_21/3RP
2
1 The structures of six compounds are shown below.
A B C
Cl Cl Cl H
O
Al Al H H C
Cl Cl Cl H H
H
D E F
NH4+ NH4+ NH4+ NH4+ Cl – Cl – Cl – Cl –

H Cl
SO42– SO42– SO42– Ba2+ Ba2+ Ba2+
SO42– SO42– SO42– Ba2+ Ba2+ Ba2+

Each compound may be used once, more than once or not at all.
(a) Which substance, A, B, C, D, E or F,
(i) gives a white precipitate on addition of an aqueous solution of

sodium sulfate, .......................... [1]
(ii) is a component of many fertilisers, .......................... [1]
(iii) contains a Group III element, .......................... [1]
(iv) is an acidic gas at room temperature, .......................... [1]
(v) turns anhydrous cobalt chloride pink, .......................... [1]
(vi) is the main component of natural gas? .......................... [1]
© UCLES 2015 0620/21/O/N/15

3
(b) Compound A can be made by direct combination of chlorine and aluminium using the apparatus
shown below.
compound A
aluminium foil Al 2Cl 6
chlorine excess chlorine
(i) On the diagram above, draw an arrow to show where heat is applied. [1]
(ii) Suggest one safety precaution that should be taken when carrying out this experiment.
. ...................................................................................................................................... [1]
(iii) Complete the symbol equation for this reaction.
2Al + ........Cl 2 → Al 2Cl 6

[1]
[Total: 9]

4
2 A student measures the maximum temperature changes when five different solids, P, Q, R, S and T,
are dissolved separately in water. She uses the apparatus shown below.
solid
thermometer
stirrer
(a) The student stirs the mixture as each solid is added.
Suggest why she does this.
....................................................................................................................................................
.............................................................................................................................................. [1]
(b) Suggest two factors which should be kept the same to make the experiment a fair test.
1. ................................................................................................................................................
2. .......................................................................................................................................... [2]
(c) The table of results is shown below.
initial temperature highest temperature

solid added
of the water / °C of the solution / °C
P 20 24
Q 18 23
R 19 16
S 22 23
T 20 18
(i) Which solid gave the greatest temperature change when dissolved in water?
. ...................................................................................................................................... [1]
(ii) Which solids gave an endothermic energy change when dissolved in water?
............................................................... and . ............................................................... [2]
© UCLES 2015 0620/21/O/N/15

5
(d) Radioactive isotopes can be used as a source of energy.
(i) Which one of the following isotopes is a radioactive isotope?

12 235 1 65
6C 92 U 1H 30 Zn
[1]
(ii) An isotope of radium, Ra, has 226 nucleons in its nucleus.
How many neutrons does this isotope contain?

Use your Periodic Table.
. ...................................................................................................................................... [1]
(iii) Give one use of radioactive isotopes in medicine.
. ...................................................................................................................................... [1]
(e) Fractions obtained from the distillation of petroleum are also sources of energy.
(i) Which one of the following fractions is used as a fuel for jet aircraft?
bitumen gasoline kerosene naphtha

[1]
(ii) Heptadecane, C17H36, is present in the fuel oil fraction.
Complete the equation for the cracking of heptadecane to form two hydrocarbons.
C17H36 → C12H26 + ....................

[1]
[Total: 11]

6
3 (a) Nickel is extracted from nickel(II) oxide, NiO, by heating with carbon.
.....NiO + C → 2Ni + ...............

[2]
(b) Nickel is refined by electrolysis.
(i) Complete the boxes to label the diagram below to show
• the negative electrode (cathode),

• the positive electrode (anode),
• the electrolyte.
+ –
[2]
(ii) At which electrode is the pure nickel formed?
. ...................................................................................................................................... [1]
(c) Molten nickel(II) chloride can be electrolysed using graphite electrodes.
(i) Predict the products of this electrolysis at
the positive electrode (anode), ............................................................................................
the negative electrode (cathode). ........................................................................................

[2]
(ii) Give two reasons why graphite is used for electrodes.
1. . ........................................................................................................................................
2. . ........................................................................................................................................
[2]
© UCLES 2015 0620/21/O/N/15

7
(d) The structures of diamond and graphite are shown below.
diamond graphite
(i) Explain how the structure of diamond relates to its use in cutting hard materials.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) Explain how the structure of graphite relates to its use as a lubricant.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
[Total: 13]

8
4 A teacher demonstrated the reactivity of calcium with water. He used the apparatus shown below.
gas syringe
water
calcium
(a) The teacher measured the volume of gas given off at various times during the reaction. He
then repeated the experiment using strontium but keeping all the conditions the same.
The graph obtained from the results is shown below.
60
strontium
50
40
calcium
volume of
30
gas / cm3
20
10
0
0 20 40 60 80 100
time / s
(i) Explain how the graph shows that strontium is more reactive than calcium.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(ii) For the reaction between calcium and water, deduce the volume of gas produced in the
first 50 seconds.
................. cm3 [1]
© UCLES 2015 0620/21/O/N/15

9
(iii) At what time was the reaction between strontium and water complete?
................. s [1]
(iv) How do you know from the graph that the reaction between calcium and water was not
complete 100 seconds after the reaction started?
. ...................................................................................................................................... [1]
(v) Suggest how the rate of reaction changes when the same mass of calcium is used but in
smaller pieces.
. ...................................................................................................................................... [1]
(b) The solution formed at the end of the reaction between strontium and water is alkaline. It is a
solution of strontium hydroxide.
The teacher titrated this solution with hydrochloric acid using the apparatus shown below.
hydrochloric acid
burette
25 cm3 strontium
hydroxide solution
(i) What piece of apparatus should be used to put exactly 25.0 cm3 of the strontium hydroxide
solution into the flask?
. ...................................................................................................................................... [1]
(ii) A few drops of litmus solution was added to the flask.
Explain why litmus is added to the flask and describe what happens to the litmus as the
titration proceeds.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]

10
(c) The graph below shows how the pH of the solution in the flask changes as the acid is added.
12
10
pH
6
0
0 10 20 30 40 50
volume of hydrochloric acid / cm 3
(i) Describe how the pH of the solution changes as the titration proceeds.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
(ii) What volume of acid had been added when the solution had a neutral pH?
. ...................................................................................................................................... [1]
(iii) The symbol equation for the reaction is
Sr(OH)2 + 2HCl → SrCl 2 + 2H2O
Give the name of the salt formed in this reaction.
. ...................................................................................................................................... [1]
[Total: 13]
© UCLES 2015 0620/21/O/N/15

11
5 A student left a cube of ice on a plate in a warm room. The diagrams below show what happened
to the ice.
at the start after 10 minutes after 30 minutes
(a) Describe and explain what happened to the ice. In your answer,
• describe and explain the change of state which occurs,

• explain this change using the kinetic particle theory.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]
(b) Water is used in industry and in the home.
(i) Give one use of water in industry.
. ...................................................................................................................................... [1]
(ii) Give one use of water in the home.
. ...................................................................................................................................... [1]
(c) The symbol equation for the reaction of lithium with water is shown below.
2Li(s) + 2H2O(l) → 2LiOH(aq) + H2(g)
(i) Write the word equation for this reaction.
. ...................................................................................................................................... [1]
(ii) Describe two observations which can be made when lithium reacts with water.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(iii) Describe how the reactivity of potassium with water compares with the reactivity of lithium
with water.
. ...................................................................................................................................... [1]

12
(d) Ethanol can be made by the reaction of steam with ethene.
(i) Draw the structure of ethene showing all atoms and all bonds.
[1]
(ii) Describe the conditions required for this reaction.
. ...................................................................................................................................... [2]
(e) The table below describes the reaction of water or steam with different metals.
metal observations
calcium reacts rapidly with cold water
cerium reacts slowly with hot water and very rapidly with steam
cobalt reacts with steam when cobalt powder is very hot
iron reacts very slowly with hot water and readily with steam
Put these metals in order of their reactivity.
[2]
[Total: 16]
© UCLES 2015 0620/21/O/N/15

13
6 When rubber is distilled, a chemical called isoprene is formed.

The structure of isoprene is shown below.
H H C H H
C C C C
H H H
(a) Deduce the molecular formula of isoprene.
.............................................................................................................................................. [1]
(b) Isoprene is an unsaturated compound.
Describe a test for an unsaturated compound.
test . ............................................................................................................................................
result . ................................................................................................................................... [2]
(c) Isoprene forms an addition polymer.
(i) What feature of the isoprene molecule is responsible for it forming an addition polymer?
. ...................................................................................................................................... [1]
(ii) Give the name of another addition polymer.
. ...................................................................................................................................... [1]
(d) Isoprene does not conduct electricity.
Explain why.
.............................................................................................................................................. [1]
(e) State the names of two substances formed when isoprene undergoes incomplete combustion.
............................................................... and ....................................................................... [2]

14
(f) Isoprene can be prepared from 3-methylbutan-1-ol.
To which group of compounds does 3-methylbutan-1-ol belong?

Tick one box.
alcohols
alkanes
alkenes
carboxylic acids
[1]
[Total: 9]
© UCLES 2015 0620/21/O/N/15

15
7 (a) Sodium is in Group I of the Periodic Table.
Describe the structure of a sodium atom.

In your answer refer to,
• the type and number of each subatomic particle present,

• the charges on each type of subatomic particle,
• the position of each type of subatomic particle in the atom.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]
(b) Sodium carbide, Na2C2, reacts with water to form ethyne, C2H2.
Na2C2 + .......H2O → .......NaOH + C2H2

[2]
(ii) Ethyne is a hydrocarbon.
What is the meaning of the term hydrocarbon?
. ...................................................................................................................................... [1]
(iii) Calculate the relative formula mass of sodium carbide.
[1]
[Total: 9]

© UCLES 2015
DATA SHEET

Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
16
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/21/O/N/15
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY


• () the word or phrase in brackets is not required but sets the context
• I ignore (mark as if this material were not present)
• R reject

Question Answer Marks
1(a)(i) F / barium chloride / BaCl2; 1

1(a)(ii) D / ammonium sulfate / (NH4)2SO4; 1
1(a)(iii) A / Al / Al2Cl6 / aluminium chloride; 1
1(a)(iv) E / HCl / hydrogen chloride; 1
1(a)(v) B / water / H2O; 1
1(a)(vi) C / methane / CH4; 1
1(b)(i) arrow under the aluminium foil; 1
1(b)(ii) fume cupboard; 1
1(b)(iii) 3 (Cl2); 1
2(a) make sure temperature change is the same throughout / make sure that there are no hot spots / no local heating; 1
2(b) any two from: 2
• same amount of solid / same mass of solid;
• same volume of water;
• same amount of stirring;
2(c)(i) Q 1
2(c)(ii) R; T; 2
235
2(d)(i) U; 1
2(d)(ii) 138; 1
2(d)(iii) cancer treatment / tracer / test thyroid function; 1
2(e)(i) kerosene; 1
2(e)(ii) C5H10; 1

3(a) 2 (Ni); 1
CO2 (on right); 1
3(b)(i) positive electrode / anode in box on left; 1
negative electrode / cathode in upper box on right; 1
electrolyte / named suitable electrolyte in lower box on right;
3 correct = [2]
1 or 2 correct = [1]
3(b)(ii) cathode / negative electrode; 2
3(c)(i) the positive electrode: chlorine; 1
the negative electrode: nickel;
3(c)(ii) inert / unreactive; 1
conducts electricity; 1
3(d)(i) giant structure / lots of carbon atoms joined to each other / lattice of covalent bonds; 1
strong (covalent) bonds throughout; 1
3(d)(ii) weak forces between layers; 1
layers can slide (over each other); 1
4(a)(i) gradient / slope is greater for strontium ora; 1

4(a)(ii) 11 (cm3); 1
4(a)(iii) 64–66 (s); 1
4(a)(iv) the line was still going up / the line was still rising; 1
4(a)(v) (rate) increases; 1
4(b)(i) (volumetric) pipette; 1
4(b)(ii) to show end point of titration / to show when the solution has been neutralised; 1
litmus goes from blue to pink (at end point); 1
4(c)(i) decreases slowly at first; 1
then sudden decrease in pH; 1
then slow decrease; 1
4(c)(ii) 26 (cm3); 1
4(c)(iii) strontium chloride; 1

5(a) melting / ice melts / ice goes from solid to liquid; 1
any four from: 4

• in solid particles regularly arranged;
• in solid particles arranged in fixed position / cannot move;
• particles in solid absorb energy;
• particles (in solid) vibrate more / particles start to move when heated;
• forces between particles (in solid) broken;
• particles in liquid slide over each other / move;
• particles in liquid not regularly arranged;

5(b)(i) coolant / for making ethanol / for making specified chemicals / solvent; 1
5(b)(ii) washing / cooking / cleaning etc.; 1
5(c)(i) lithium + water → lithium hydroxide + hydrogen; 1
5(c)(ii) any two from: 2
• floats on surface (of water);
• bubbles of gas;
• fizzes / fizzing sound;
• decreases in size / disappears;
• moves around;
5(c)(iii) (potassium) more reactive / lithium less reactive; 1
5(d)(i) correct structure of ethene; 1
5(d)(ii) high temperature; 1
catalyst / phosphoric acid; 1
5(e) cobalt → iron → cerium → calcium; 2
one pair reversed or all reversed = [1]
6(a) C5H8; 1

6(b) bromine / bromine water / aqueous bromine; 1

decolourised / goes from orange to colourless; 1
6(c)(i) double bond; 1
6(c)(ii) poly(ethene) / any other addition polymer; 1
6(d) it is a molecule / covalent compound; 1
6(e) any two from: carbon or soot / carbon monoxide / water; 2
6(f) alcohols / first box ticked; 1
7(a) any five from: 5

• 11 electrons;
• electrons – (negatively) charged;
• electrons outside nucleus in shells;
• nucleus contains protons and neutrons;
• protons – (positively) charged;
• neutrons no charge;
• 11 protons;
• 12 neutrons;
• electron arrangement 2,8,1 / 1 electron in outer shell;
7(b)(i) 2 (NaOH); 1
2 (H2O); 1
7(b)(ii) substance containing carbon and hydrogen only / substance containing carbon and hydrogen and no other element; 1
7(b)(iii) 70; 1

*7761599169*
CHEMISTRY 0620/31


1 hour 15 minutes

IB15 11_0620_31/3RP
2
1 (a) The symbols of six particles are shown below.
Na+ Ca2+ Kr P Si O2–
Select from the list of particles to answer the following questions. A particle may be selected
once, more than once or not at all.
(i) Which two ions have the same electronic structure? . .................................................. [1]
(ii) Which ion has the same electronic structure as an atom of argon? . ............................ [1]
(iii) Which atom can form an ion of the type X3–? ................................................................ [1]
(iv) Which atom can form a hydride which has a formula of the type XH4? . ....................... [1]
(b) (i) How many protons, neutrons and electrons are there in one copper(II) ion 64
29 Cu 2+ ?
number of protons .....................
number of neutrons .....................
number of electrons .....................

[2]
(ii) 45
21 Sc represents an atom of scandium.
How many nucleons and how many charged particles are there in one atom of scandium?
number of nucleons .....................
number of charged particles .....................

[2]
23 24
(c) Two different atoms of sodium are 11 Na and 11 Na .
(i) Explain why these two atoms are isotopes.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) 24
11 Na is radioactive. It changes into an atom of a different element which has one more
proton.
Identify this element.
. ...................................................................................................................................... [1]
(iii) State two uses of radioactive isotopes.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
[Total: 13]
© UCLES 2015 0620/31/O/N/15

3
2 Describe how to separate the following. In each example, give a description of the procedure used
and explain why this method works.
(a) Copper powder from a mixture containing copper and zinc powders.
procedure ...................................................................................................................................
....................................................................................................................................................
explanation .................................................................................................................................
....................................................................................................................................................
[3]
(b) Nitrogen from a mixture of nitrogen and oxygen.
procedure ...................................................................................................................................
....................................................................................................................................................
explanation .................................................................................................................................
....................................................................................................................................................
[3]
(c) Glycine from a mixture of the two amino acids glycine and alanine. Glycine has the lower Rf
value.
procedure ...................................................................................................................................
....................................................................................................................................................
explanation .................................................................................................................................
....................................................................................................................................................
[2]
(d) Magnesium hydroxide from a mixture of magnesium hydroxide and zinc hydroxide.
procedure ...................................................................................................................................
....................................................................................................................................................
explanation .................................................................................................................................
....................................................................................................................................................
[3]
[Total: 11]

4
3 Sulfuric acid is made by the Contact process.
(a) Sulfur is burned by spraying droplets of molten sulfur into air.
Suggest and explain an advantage of using this method.
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) The following equation represents the equilibrium in the Contact process.
2SO2(g) + O2(g) 2SO3(g)
Oxygen is supplied from the air.

The composition of the reaction mixture is 1 volume of sulfur dioxide to 1 volume of oxygen.
What volume of air contains 1 dm3 of oxygen?
....................................................................................................................................... dm3 [1]
(c) Sulfur dioxide is more expensive than air.
What is the advantage of using an excess of air?
....................................................................................................................................................
.............................................................................................................................................. [2]
(d) The forward reaction is exothermic. The reaction is usually carried out at a temperature between
400 and 450 °C.
(i) What is the effect on the position of equilibrium of using a temperature above 450 °C?
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) What is the effect on the rate of using a temperature below 400 °C?
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
© UCLES 2015 0620/31/O/N/15

5
(e) A low pressure, 2 atmospheres, is used. At equilibrium, about 98% SO3 is present.
(i) What is the effect on the position of equilibrium of using a higher pressure?
. ...................................................................................................................................... [1]
(ii) Explain why a higher pressure is not used.
. ...................................................................................................................................... [1]
(f) Name the catalyst used in the Contact process.
.............................................................................................................................................. [1]
(g) Describe how concentrated sulfuric acid is made from sulfur trioxide.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 15]

6
4 (a) Synthetic polymers are disposed of in landfill sites and by burning.
(i) Describe two problems caused by the disposal of synthetic polymers in landfill sites.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) Describe one problem caused by burning synthetic polymers.
. ...................................................................................................................................... [1]
(b) State two uses of synthetic polymers.
....................................................................................................................................................
.............................................................................................................................................. [1]
(c) The structural formulae of two synthetic polymers are given below.
CH2 CH CH2 CH
polymer A
CH3 CH3
O O O O
polymer B
C C O O C C O O
(i) Draw the structural formula of the monomer of polymer A.
[2]
(ii) Identify the functional group circled in polymer B.
. ...................................................................................................................................... [1]
(iii) Deduce the two types of organic compound which have reacted to form polymer B.
. ...................................................................................................................................... [2]
© UCLES 2015 0620/31/O/N/15

7
(d) Explain the difference between addition and condensation polymers. Classify A and B as
either addition or condensation polymers.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 12]

8
5 (a) A compound, X, contains 55.85% carbon, 6.97% hydrogen and 37.18% oxygen.
(i) How does this prove that compound X contains only carbon, hydrogen and oxygen?
. ...................................................................................................................................... [1]
(ii) Use the above percentages to calculate the empirical formula of compound X.
. ...................................................................................................................................... [2]
(iii) The Mr of X is 86.
What is its molecular formula?
. ...................................................................................................................................... [2]
(b) (i) Bromine water changes from brown to colourless when added to X.
What does this tell you about the structure of X?
. ...................................................................................................................................... [1]
(ii) Magnesium powder reacts with an aqueous solution of X. Hydrogen is evolved.
What does this tell you about the structure of X?
. ...................................................................................................................................... [1]
(iii) X contains two different functional groups.
Draw a structural formula of X.
[1]
[Total: 8]
© UCLES 2015 0620/31/O/N/15

9
6 Carbon and silicon are elements in Group IV. They both form oxides of the type XO2.
(a) Silicon(IV) oxide, SiO2, has a macromolecular structure.
(i) Describe the structure of silicon(IV) oxide.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
(ii) State three properties which silicon(IV) oxide and diamond have in common.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
(iii) How could you show that silicon(IV) oxide is acidic and not basic or amphoteric?
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(b) Explain why the physical properties of carbon dioxide are different from those of diamond and
silicon(IV) oxide.
....................................................................................................................................................
.............................................................................................................................................. [1]
[Total: 9]

10
7 The rate of a photochemical reaction is affected by light.
(a) The decomposition of silver bromide is the basis of film photography. This is a redox reaction.
2AgBr → 2Ag + Br2

cream black
step 1 2Br – → Br2 + 2e–
step 2 Ag+ + e– → Ag
(i) Which step is reduction? Explain your answer.
. ...................................................................................................................................... [1]
(ii) Which ion is the oxidising agent? Explain your answer.
. ...................................................................................................................................... [1]
(b) A piece of white paper was coated with silver bromide and exposed to the light. Sections of the
paper were covered as shown in the diagram.
paper coated with

silver bromide
not covered
covered with
thin paper
covered with
thick card
Predict the appearance of the different sections of the paper after exposure to the light and the
removal of the card. Explain your predictions.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
© UCLES 2015 0620/31/O/N/15

11
(c) Photosynthesis is another example of a photochemical reaction. Green plants can make simple
carbohydrates, such as glucose. These can polymerise to make more complex carbohydrates,
such as starch.
(i) Write a word equation for photosynthesis.
. ...................................................................................................................................... [2]
(ii) Name the substance which is responsible for the colour in green plants and is essential for
photosynthesis.
. ...................................................................................................................................... [1]
(iii) The structural formula of glucose can be represented by H O O H.
Draw part of the structural formula of starch which contains two glucose units.
[2]
(iv) Living organisms need carbohydrates for respiration.
What is meant by respiration?
. ...................................................................................................................................... [1]
[Total: 12]

© UCLES 2015
DATA SHEET

Group
1 4
H He
Hydrogen Helium
1 2
7 9 11 12 14 16 19 20
Li Be B C N O F Ne
3 4 5 6 7 8 9 10
23 24 27 28 31 32 35.5 40
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
12
85 88 89 91 93 96 101 103 106 108 112 115 119 122 128 127 131
0620/31/O/N/15
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178 181 184 186 190 192 195 197 201 204 207 209
55 56 57 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
226 227
Fr Ra Ac
87 88 89
140 141 144 150 152 157 159 162 165 167 169 173 175
58 59 60 61 62 63 64 65 66 67 68 69 70 71
0620 CHEMISTRY


• R reject

1(a)(i) Na+ / sodium and O2– / oxide; 1

2+
1(a)(ii) Ca / calcium; 1
1(a)(iii) P / phosphorus; 1
1(a)(iv) Si / silicon; 1
1(b)(i) • number of protons = 29; 2
• number of neutrons = 35;
• number of electrons = 27;
three correct = [2]; two correct = [1]

1(b)(iii) number of nucleons = 45; 1
number of charged particles = 42; 1
1(c)(i) have same proton number / same element / same atomic number; 1
different number of neutrons / nucleons / mass number; 1
1(c)(ii) magnesium / Mg; 1
1(c)(iii) any two from: 2
• treating cancer or radiotherapy;
• biological tracer;
• thickness (of paper or foil);
• (checking for) leaks / cracks (in pipes);
• (carbon) dating;
• (generating) energy / electricity;
• smoke detectors;
• fill levels in packages;
• sterilising surgical instruments;

2(a) add a (dilute) acid; 1

filter; 1
copper does not react or dissolve / zinc reacts or dissolves or forms a salt; 1
2(b) diffusion (through a membrane); 3
nitrogen diffuses faster;
because it has the smaller Mr;
or
(turn into) liquid;
(fractional) distillation;
different boiling points;
or
burn a named substance to make non-gaseous product;
oxygen reacts / nitrogen does not react;
name of product of combustion;
2(c) chromatography; 1
use a locating agent / the two acids move at different rates / alanine travels faster / alanine higher up paper / travels further; 1
2(d) add sodium hydroxide solution; 1
filter; 1
zinc hydroxide (is amphoteric it) will react or will dissolve / magnesium hydroxide does not react or does not dissolve; 1

3(a) fast(er) reaction; 1

large(r) surface area; 1
3(b) 4.76 (dm3); 1
3(c) moves equilibrium to right; 1
increases yield (of sulfur trioxide) / uses up more sulfur dioxide; 1
3(d)(i) moves equilibrium to left; 1
(forward reaction) exothermic; 1
3(d)(ii) decrease rate; 1
molecules have less energy / move slower; 1
fewer collisions (per second) / fewer particles have the activation energy / fewer collisions have the activation energy; 1
3(e)(i) moves to right; 1
3(e)(ii) high yield at 2 atm; 1
3(f) vanadium(V) oxide / vanadium pentoxide; 1
3(g) M1 dissolve / react sulfur trioxide in (concentrated) sulfuric acid; 1
add water to product of M1; 1
4(a)(i) any two from: 2

• shortage of sites / landfill sites fill up;
• visual pollution / litter;
• danger to wild life;
4(a)(ii) (produce) toxic gases or CO or HCl or HF / carbon dioxide / greenhouse gases; 1
bags / clothing or specified clothing / packaging / bowls / cups / plates / flooring / carpets / pipes / insulation / non-stick
coatings / ropes;

4(c)(i) CH2=CHCH3 2
double bond is shown;
rest of structure correct;
4(c)(ii) ester; 1
4(c)(iii) (carboxylic) acid; 1
alcohol; 1
4(d) addition – polymer only product / only one product; 1
condensation – (polymer and) simple molecule / water / hydrogen chloride made; 1
polymer A is an addition polymer and polymer B is a condensation polymer; 1
5(a)(i) adds up to 100%; 1

5(a)(ii) M1 55.85/12 and 6.97(/1) and 37.2/16; 1
or evaluation 4.650 6.970 2.325;
M2 C2H3O; 1
correct answer with no working = [2]
5(a)(iii) M1 (86/)43; 1
M2 C4H6O2; 1
correct answer with no working = [2]
5(b)(i) unsaturated / C=C double bond / alkene; 1
5(b)(ii) (organic / carboxylic) acid / contains or releases H+ ions; 1
5(b)(iii) CH3CH=CHCOOH / CH2=CHCH2COOH / CH2=CH(CH3)COOH; 1

6(a)(i) any three from: 3

• each oxygen is joined to two silicons / atoms;
• each silicon is joined to four oxygens / atoms;
• tetrahedral (around silicon) / similar to diamond;
• linear around oxygen;
6(a)(ii) any three from: 3
• high melting point / boiling point;
• hard;
• strong;
• (colourless) crystalline (solid);
• brittle / not malleable;
• poor / non-conductor (of electricity) / insulator;
• insoluble (in water);
6(a)(iii) SiO2 reacts with or dissolves in or neutralises an acid or acidic oxide; 1
SiO2 does not react or dissolve in or neutralise an alkali or base or basic oxide; 1
6(b) carbon dioxide has a simple molecular structure; 1

7(a)(i) step 2 and it is electron gain / oxidation state decreases; 1

7(a)(ii) silver (ion) and it accepts electrons / gets reduced / oxidation state decreases; 1
7(b) prediction:
the ‘not covered’ section will be black; 1
the ‘covered in thick card’ section will be white / cream; 1
the ‘covered in thin card’ section will be grey; 1
explanation:
the more light, the more silver ions are reduced; 1
7(c)(i) carbon dioxide + water → glucose + oxygen
reactants correct; 1
products correct; 1
7(c)(ii) chlorophyll; 1
7(c)(iii)
1
one correct –O– link between rectangles;
1
two correct glucose units with continuation bonds;
7(c)(iv) the reaction of glucose with oxygen to release (carbon dioxide and water and) energy; 1
or
the reaction of glucose in a biological system to release energy;

CHEMISTRY 0620/51

*0468745378*
where relevant.
by phone: +44 1223 553554,
by fax: +44 1223 553558,
IB15 11_0620_51CI/3RP
2
For Question 1
[F] (a) five strips of magnesium ribbon, each 4 cm long , labelled magnesium ribbon
(b) a 100 cm3 beaker
[H] (c) 50 cm3 of sulfuric acid of concentration 1.0 mol / dm3, labelled A
[H] (d) 50 cm3 of sulfuric acid of concentration 0.8 mol / dm3, labelled B
[H] (e) 50 cm3 of sulfuric acid of concentration 0.6 mol / dm3, labelled C
[H] (f) 50 cm3 of sulfuric acid of concentration 0.5 mol / dm3, labelled D
(g) a stirring rod
(i) a 50 cm3 measuring cylinder
(j) a stop clock or timer. Candidates may use their own watches
(k) teat pipette
(l) a test-tube
(m) splint
(n) Bunsen burner and matches
(o) a stirring thermometer, 0-110 °C
(p) a 10 cm3 measuring cylinder
© UCLES 2015 0620/51/CI/O/N/15

3
For Question 2
[H] (a) a stoppered test-tube containing about 8 cm3 of aqueous iron(II) chloride, FeCl 2.4H2O,
of concentration 0.2 mol / dm3 labelled solution X. This solution should be prepared just
before the examination.
[N][H] (b) a stoppered test-tube containing about 6 cm3 of aqueous silver nitrate, AgNO3, of
concentration 0.1 mol / dm3, labelled solution Y
(c) rack of eight test-tubes with a stopper to fit tubes
(d) boiling tube with a stopper to fit
(e) red litmus papers
[H] (f) aqueous sulfuric acid of concentration 1.0 mol / dm3
[C] (g) aqueous sodium hydroxide of concentration 1.0 mol / dm3
(h) aqueous ammonia of concentration 1.0 mol / dm3
[N][H] (i) aqueous silver nitrate of suitable concentration to give a positive halide test
[C] (j) aqueous nitric acid of concentration 1.0 mol / dm3
(k) aqueous hydrochloric acid of concentration 1.0 mol / dm3
(l) aqueous potassium manganate(VII) of concentration 0.05 mol / dm3
(m) small piece (approximately 1 cm square) of aluminium foil
(n) about 2 cm3 of aqueous potassium iodide of concentration 0.2 mol / dm3
(o) spatula
(p) a 10 cm3 measuring cylinder
(q) a Bunsen burner and matches
(r) teat pipettes
(s) distilled water
(t) test-tube holder

4
© UCLES 2015 0620/51/CI/O/N/15

5

6
© UCLES 2015 0620/51/CI/O/N/15

7
NOVEMBER 2015
penalised.
© UCLES 2015 0620/51/CI/O/N/15

[Turn over
8
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
© UCLES 2015 0620/51/CI/O/N/15

*3376642215*
CHEMISTRY 0620/51
1 hour 15 minutes

Total
IB15 11_0620_51/3RP
2
1 You are going to investigate the rate of reaction when magnesium ribbon reacts with four solutions
of dilute sulfuric acid, of different concentrations, labelled solutions A, B, C and D. The sulfuric acid
is in excess in all experiments.
Instructions
You are going to carry out five experiments.
(a) Experiment 1
Using a measuring cylinder, pour 30 cm3 of dilute sulfuric acid A into the beaker.
Start the timer and add the 4 cm length of magnesium to the sulfuric acid in the beaker.
Stir the mixture constantly.
Measure the time taken for all of the magnesium to react and disappear.
Record the time in the table below.
Rinse out the beaker with distilled water.
(b) Experiment 2
Repeat Experiment 1, using the solution B of sulfuric acid. Record the time in the table.
(c) Experiment 3
Repeat Experiment 1, using the solution C of sulfuric acid. Record the time in the table.
(d) Experiment 4
Repeat Experiment 1, using the solution D of sulfuric acid. Record the time in the table.
Experiment solution of concentration of time for magnesium to

number sulfuric acid sulfuric acid in mol / dm3 completely disappear in seconds
1 A 1.0
2 B 0.8
3 C 0.6
4 D 0.5
[4]
(e) Experiment 5
Pour about 3 cm3 of the solution C of sulfuric acid into a test-tube and record its temperature.
Add a 4 cm length of magnesium.
Record all of your observations and test the gas given off with a splint.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
© UCLES 2015 0620/51/O/N/15

3
(f) Plot the results for Experiments 1, 2, 3 and 4 on the grid and draw a smooth line graph.
180
160
140
120
100
time in
seconds
80
60
40
20
0
0 0.2 0.4 0.6 0.8 1.0 1.2
concentration of sulfuric acid in mol / dm3
[3]
(g) (i) From your graph, deduce the concentration of the sulfuric acid if the time for the reaction
was 80 s.
.................................... mol / dm3 [2]

4
(ii) From your graph, deduce how long the reaction would take if a solution of sulfuric acid of
concentration 1.2 mol / dm3 was used.
.................................... s [2]
(h) Why was the same amount of magnesium used in Experiments 1, 2, 3 and 4?
.............................................................................................................................................. [1]
(i) Use your observations in Experiment 5 to answer these questions.
(i) What type of chemical reaction occurs when magnesium reacts with sulfuric acid?
....................................................................................................................................... [1]
(ii) Identify the gas given off.
....................................................................................................................................... [1]
(iii) Suggest the effect on the temperature change if this experiment was repeated using 2 cm
of magnesium ribbon.
.............................................................................................................................................
....................................................................................................................................... [1]
(j) Suggest a different method which could be used to investigate the rate of the reaction between
magnesium and sulfuric acid. State the difference in the apparatus used and measurements to
be taken.
apparatus ...................................................................................................................................
measurements ...........................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 20]
© UCLES 2015 0620/51/O/N/15

5
2 You are provided with two metal salt solutions, X and Y.

Carry out the following tests on X and Y, recording all of your observations in the tables.
Conclusions must not be written in the tables.
tests observations
tests on solution X
(a) Describe the appearance of solution X. ................................................................ [1]
Divide the solution into four equal portions in

(b) To the first portion of solution add about

1 cm3 of dilute nitric acid followed by
aqueous silver nitrate. ................................................................ [2]
(c) To the second portion of solution add about

1 cm3 of aqueous sodium hydroxide and
shake the mixture and leave to stand. ................................................................ [1]
Note how the mixture changes after five

minutes. ................................................................ [1]
(d) To the third portion of solution add excess

aqueous ammonia. ................................................................ [1]
(e) To the fourth portion of solution add a

few drops of dilute sulfuric acid followed
by about 1 cm3 of aqueous potassium
manganate(VII). ................................................................ [1]
Now add aqueous sodium hydroxide to the

mixture. ................................................................ [2]

6
tests observations
tests on solution Y
Divide the solution into three equal portions in

(f) To the first portion of the solution add about

1 cm3 of dilute hydrochloric acid. ................................................................ [1]
(g) Tip the second portion of the solution into

a boiling tube. Add about 1 cm3 of aqueous
sodium hydroxide and shake the mixture.
Add one small piece of aluminium foil to ......................................................................
the mixture and warm gently. Test the gas
given off with red litmus paper. ................................................................ [3]
(h) To the third portion of the solution add

aqueous potassium iodide. ................................................................ [2]
(i) What conclusions can you draw about solution X?
....................................................................................................................................................
.............................................................................................................................................. [3]
(j) What conclusions can you draw about solution Y?
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 20]
© UCLES 2015 0620/51/O/N/15

7
BLANK PAGE
© UCLES 2015 0620/51/O/N/15

8
Test for anions

produced

aluminium (Al 3+)
Test for gases

© UCLES 2015 0620/51/O/N/15

0620 CHEMISTRY


• R reject

1(d) time boxes correctly completed, ascending in magnitude; 3 I: decimal places if given
in seconds; 1
1(e) any two from: 2
• effervescence / bubbles;
• lighted splint pops;
• temperature increased;
1(f) points correctly plotted: 2
4 correct = 2
3 correct = 1
2 or fewer correct = 0
smooth line graph; 1

1(g)(i) value from the graph quoted; 1
clearly shown on the graph; 1
1(g)(ii) value from the graph quoted; 1
extrapolation shown clearly; 1
1(h) idea of fair test / comparability; 1 A: variable was sulfuric acid
1(i)(i) exothermic / redox / displacement; 1 I: neutralisation
1(i)(ii) hydrogen; 1
1(i)(iii) values halved; 1 A: smaller temperature change
1(j) apparatus
gas syringe / measuring cylinder over water / thermometer; 1
measurements
volume of gas / temperature of reaction; 1
over time; 1

2(a) yellow / green; 1 R: precipitate / solid

compare with Supervisor’s result
2(b) white; 1
precipitate; 1
2(c) green precipitate; 1
brown colour on sides / top of tube; 1
2(d) green precipitate; 1
2(e) (pink to) colourless; 1
brown; 1
precipitate; 1
2(f) white precipitate; 1
2(g) brown precipitate; 1 I: black
bubbles; 1
litmus paper turns blue / pH 10–12; 1
2(h) yellow; 1
precipitate; 1
2(i) iron; 1
(II); 1
chloride; 1
2(j) silver / lead; 1
nitrate; 1

0620 CHEMISTRY


• R reject

1(a) (teat) pipette; 1

evaporating dish / basin; 1 R: watch glass / clock glass / crucible / petri dish
1(b)(i) wire; 1
(metal) with high melting point; 1
1(b)(ii) open; 1
1(c)(i) pH > 7 / purple / blue / dark green; 1
1(c)(ii) milky / white / white precipitate / cloudy; 1
2(a) straight line, drawn with a ruler, missing the point at n = 3; 1

2(b) 2 from: 2 R: human error
• measuring / recording error / anomalous result; I: impurities
• equal amounts not burnt;
• heat losses;
• incomplete combustion;
2(c) reading from the graph / expected answer 4100 ± 50; 1
indication of extrapolation from the graph; 1
2(d) for butane n = 4, ethane n = 2; 1
value for ethane = 1550; 1
butane = 2800 / about twice value or not exactly twice value; 1

3(a) electrolysis; 1
3(b) bulb lights / bubbles; 1
3(c) platinum; 1 R: copper
3(d) glowing splint; 1 R: relights a lighted splint
relights; 1 A: lighted splint glows brighter
3(e) hydrogen (ions) positive / opposites attract 1
3(f) chlorine produced; 1
poisonous / toxic; 1
4(d) all time readings correctly recorded: 48, 68, 96, 132 3
4 correct = 3
3 correct = 2
2 correct = 1
0 or 1 correct = 0
in seconds; 1
4(e) all points correctly plotted: 48, 68, 96, 132 2
4 correct = 2
3 correct = 1
2 or fewer correct = 0
smooth line graph; 1

4(f)(i) value from the graph, 0.7; 1
shown clearly on the graph; 1

4(f)(ii) value from the graph, e.g. 34 s; 1

extrapolation shown clearly; 1
4(g) idea of fair test / comparability; 1
4(h) 21 (°C); 1
49 (°C); 1
4(i)(i) exothermic / redox / displacement; 1 I: neutralisation
4(i)(ii) hydrogen; 1
4(i)(iii) values halved; 2 ‘smaller temperature change’ = 1 mark
4(j) apparatus
gas syringe / thermometer; 1
measurements
volume of gas / temperature of reaction; 1
over time; 1
5(a) yellow / green; 1 R: reference to ppt.

5(b) white precipitate; 1
5(c) green; 1
precipitate; 1
5(d) green precipitate; 1
5(e) brown; 1
precipitate; 1
5(i) silver / lead; 1
nitrate; 1

6 7 from: 7
• weighed amount / x g of toothpaste;
• add water;
• stir / heat;
• filter (to obtain calcium carbonate);
• wash;
• dry;
• weigh residue;
• calculate percentage calcium carbonate;

CHEMISTRY 0620/11
Paper 1 Multiple Choice (Core) October/November 2016
45 minutes
Soft clean eraser
*6275559010*

IB16 11_0620_11/6RP
2
1 ‘Particles moving very slowly from an area of higher concentration to an area of lower
concentration.’
Which process is being described?
A a liquid being frozen

B a solid melting
C a substance diffusing through a liquid
D a substance diffusing through the air
2 A student mixes 25 cm3 samples of dilute hydrochloric acid with different volumes of aqueous
sodium hydroxide.
In each case, the student measures the change in temperature to test if the reaction is
exothermic.
Which piece of apparatus is not needed?
A B C D
burette clock pipette thermometer
© UCLES 2016 0620/11/O/N/16

3
3 Information about the solubility of four solids, P, Q, R and S, is given in the table.
P Q R S
solubility in water dissolves insoluble insoluble dissolves
A student attempted to separate mixtures of these solids using the following method.
1 Add the mixture to a beaker of water and stir.

2 Filter the mixture.
3 Crystallise one of the solids from the filtrate.
Which of the following mixtures could not be separated by this method?
A a mixture of P and R
B a mixture of Q and P
C a mixture of Q and R
D a mixture of R and S
4 The table shows information about atoms of three different elements.

element
chlorine 17 35 17 W 17
chlorine 17 X 17 19 17
argon Y 40 18 22 18
potassium 19 39 19 20 Z
W X Y Z
A 18 35 18 19
B 18 36 18 19
C 19 35 19 18
D 19 36 19 18

4
5 The diagrams show the structures of two forms of the same element.
T U
What are the reasons for using T in cutting tools and U as a lubricant?
T U
A It is very hard because each atom is The layers can slide over each other
held in place by strong covalent bonds. because the covalent bonds are weak.
B It is very hard because each atom is The layers can slide over each other
held in place by strong covalent bonds. due to weak forces between the layers.
C It is very hard because there are The layers can slide over each other
no electrons able to move. because the covalent bonds are weak.
D It is very hard because there are The layers can slide over each other
no electrons able to move. due to weak forces between the layers.
6 Ions are formed by elements losing or gaining electrons.
A Metal atoms gain electrons to form positive ions.

B Non-metal atoms lose electrons to form positive ions.
C The charge on an ion is always either +1 or –1.
D Group I ions have the same electronic structure as noble gases.
7 A molecule of X contains two carbon atoms, four hydrogen atoms and two oxygen atoms.
What is the formula of X?
A CH2CO2H B CH3COH C CH3COOH D C2H3COOH
© UCLES 2016 0620/11/O/N/16

5
8 Concentrated aqueous potassium chloride is electrolysed using platinum electrodes.
The solution contains the ions K+, Cl –, H+ and OH–.
Which electrodes are the ions attracted to during this electrolysis?
anode cathode
A Cl – and K+ H+ and OH–

B Cl – and OH– H+ and K+
C H+ and K+ Cl – and OH–
D H+ and OH– Cl – and K+
9 Which apparatus could be used to electroplate an iron nail with copper?
A B key
+ – + – = copper sheet
= iron nail
C D
+ – + –
aqueous iron(II) sulfate

6
thermometer
anhydrous
copper(II) sulfate
water
Which row shows the temperature change and the type of reaction taking place?
A decrease endothermic
B decrease exothermic
C increase endothermic
D increase exothermic
11 The combustion of element X releases large amounts of energy.
What is X?
A ethanol
B hydrogen
C methane
D uranium
© UCLES 2016 0620/11/O/N/16

7
12 The rate of reaction between magnesium and excess dilute hydrochloric acid was followed by
measuring the mass of magnesium present at regular time intervals.
Two experiments were performed.
Both experiments used 0.1 g of magnesium ribbon. The acid in experiment 1 was less
concentrated than in experiment 2.
Which graph shows the results of the experiments?
A B
mass of mass of
magnesium magnesium
1 2
2 1
0 0
0 time 0 time
C D
2 1
mass of 1 mass of 2
magnesium magnesium
0 0
0 time 0 time
13 Which reaction is reversible?
A CuCO3 + 2HCl → CuCl 2 + CO2 + H2O
B CuSO4.5H2O → CuSO4 + 5H2O
C 2Na + 2H2O → 2NaOH + H2
D NaOH + HCl → NaCl + H2O
14 Tin is formed when tin(II) oxide is heated with carbon.
What happens to the tin in the tin(II) oxide in this reaction?
A It is burnt.
B It is electrolysed.
C It is oxidised.
D It is reduced.

8
Which element forms an acidic oxide?
A B
C
D
16 Four substances, P, Q, R and S, are tested as shown.
substance
test
P Q R S
gas given off gas given off
dilute hydrochloric
which ‘pops’ with which turns no reaction no reaction
acid added
a lighted splint limewater milky
dilute aqueous gas given off

sodium hydroxide which turns
added and no reaction no reaction damp, red litmus no reaction
warmed gently paper blue
What are P, Q, R and S?
P Q R S
A Mg Na2CO3 NH4Cl NaCl

B Mg NH4Cl Na2CO3 NaCl
C Mg Na2CO3 NaCl NH4Cl
D Na2CO3 Mg NaCl NH4Cl
17 Acids can react with metal oxides, carbonates and metals.
Which reactions produce a gas?
acid with acid with acid with

metal oxide carbonate metal
A key
B = gas is produced
C = no gas is produced
D
© UCLES 2016 0620/11/O/N/16

9
18 The apparatus shown is used to prepare aqueous copper(II) sulfate.
filter paper
stirrer
excess of solid X
solid X
Y aqueous
copper(II) sulfate
heat
What are X and Y?
X Y
A copper aqueous iron(II) sulfate

B copper(II) chloride sulfuric acid
C copper(II) oxide sulfuric acid
D sulfur aqueous copper(II) chloride
19 Which statement about trends in the Periodic Table is not correct?
A Elements in the same period have the same number of electron shells.
B The elements change from metals to non-metals from left to right.
C The number of protons in an atom of an element increases from left to right.
D The oxides of the elements change from acidic to basic from left to right.
20 What is not a property of Group I metals?
A They are soft and can be cut with a knife.

B They react when exposed to oxygen in the air.
C They produce an acidic solution when they react with water.
D They react rapidly with water producing hydrogen gas.
21 Which statement about the element with proton number 54 is correct?
A It burns in the air to form an oxide.

B It could be used in balloons because it has a very low density.
C It is a gas at room temperature.
D It is reactive because it has a full outer shell of electrons.

10
22 Which element is a transition element?

A orange 113
B orange 1535
C white 113
D white 1535
23 Which row describes the trends in the properties of the Group VII elements as the group is
descended?
reactivity with
colour density
halide ions
A darkens decreases increases

B darkens increases decreases
C lightens decreases increases
D lightens increases decreases
24 Four metals are listed in decreasing order of reactivity.
magnesium
zinc
iron
copper
Where should titanium be placed in the list?
A below copper
© UCLES 2016 0620/11/O/N/16

11
25 Impure iron from the blast furnace is converted to steel as shown.
oxygen
impure molten iron
Which statement about the process is correct?
A Acidic oxides are added to remove alkaline impurities.

B Coke is added as a reducing agent.
C Oxygen is blown in to oxidise the impure iron.
D The steel produced contains less carbon than the impure iron.
26 A student added dilute hydrochloric acid to four metals and recorded the results.
Some of the results are not correct.
results
metal gas given off
1 copper yes
2 iron yes
3 magnesium no
4 zinc yes
Which two results are correct?

12
27 Some properties of three metals, P, Q and R, are shown.
metal density resistance to corrosion electrical conductivity
P low high very good

Q high high very good
R low low good
Which metals would be suitable for use in electrical wiring and aircraft manufacture?
electrical wiring aircraft manufacture
A P Q
B Q P
C Q R
D R P
28 One sample of sea-water is distilled while another sample of sea-water is filtered.
Which statement about the samples is correct?
A The distilled sample boils at exactly 100 °C and contains dissolved salts.
B The distilled sample boils at 103 °C and does not contain dissolved salts.
C The filtered sample boils at 103 °C and contains dissolved salts.
D The filtered sample boils at exactly 100 °C and does not contain dissolved salts.
29 Air is a mixture of gases.
Which gas is present in the largest amount?
A argon
B carbon dioxide
C nitrogen
D oxygen
© UCLES 2016 0620/11/O/N/16

13

31 A mixture of two substances, X and Y, is heated.
The damp, red litmus paper turns blue.
damp, red
litmus paper
X and Y
gentle heat
What are X and Y?
X Y
A aluminium nitrate hydrochloric acid

B aluminium nitrate sodium hydroxide solution
C ammonium chloride hydrochloric acid
D ammonium chloride sodium hydroxide solution

14
32 In the experiment shown, a white precipitate forms in the limewater.
X
limewater
What are X and Y?
X Y
A aqueous sodium hydroxide zinc

B aqueous sodium hydroxide zinc carbonate
C dilute sulfuric acid zinc
D dilute sulfuric acid zinc carbonate
33 Which box corresponds to limestone?
Does limestone contain carbon?
yes no
Does limestone burn? Does limestone burn?
yes no yes no
A B C D
© UCLES 2016 0620/11/O/N/16

15
34 Petroleum is an important fossil fuel.
Which row correctly describes petroleum?
type of substance composition

A compound mainly hydrocarbons
B compound only hydrogen and carbon
C mixture mainly hydrocarbons
D mixture only hydrogen and carbon
35 Butane reacts as shown.
catalyst
butane butene + hydrogen
and heat
What is this type of reaction?
A combustion
B cracking
C polymerisation
D reduction
36 Which substance is in the same homologous series as methanol?
A B C D
H H H H O H H H H
H C C C H H C C H C C OH C C
H H H H OH H H H H
37 Which statement could not be correct for an alkane?
A It burns readily in a plentiful supply of air to form only carbon dioxide and water.
B It decolourises aqueous bromine.
C It has a boiling point of – 42 °C.

D The carbon and hydrogen atoms in the molecule are joined by sharing pairs of electrons.

16
38 In which conical flask will ethanol be produced?
A B C D
water and sugar and water, sugar water and

sugar yeast and yeast yeast
39 Which molecule can be polymerised?
A B C D
H H H H H H O
H C H H C C H C C H C C
H H H H H H O H
40 Which row describes what happens when ethanol burns in air?
a white powder heat energy carbon dioxide water

is left is given out is formed is formed
A
B
C
D
© UCLES 2016 0620/11/O/N/16

17
BLANK PAGE
© UCLES 2016 0620/11/O/N/16

18
BLANK PAGE
© UCLES 2016 0620/11/O/N/16

19
BLANK PAGE
© UCLES 2016 0620/11/O/N/16

The Periodic Table of Elements
Group
© UCLES 2016
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
20
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/11/O/N/16
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/11
MARK SCHEME
Maximum Mark: 40
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level
components.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.

Question Question
Key Key
Number Number
1 C 21 C
2 B 22 B
3 C 23 B
4 B 24 C
5 B 25 D
6 D 26 D
7 C 27 B
8 B 28 C
9 A 29 C
10 D 30 B
11 B 31 D
12 A 32 D
13 B 33 B
14 D 34 C
15 C 35 B
16 A 36 C
17 C 37 B
18 C 38 C
19 D 39 C
20 C 40 B
© UCLES 2016
CHEMISTRY 0620/21
Paper 2 Multiple Choice (Extended) October/November 2016
45 minutes
Soft clean eraser
*6942475041*

IB16 11_0620_21/6RP
2
1 ‘Particles moving very slowly from an area of higher concentration to an area of lower
concentration.’
Which process is being described?
A a liquid being frozen

B a solid melting
C a substance diffusing through a liquid
D a substance diffusing through the air
2 A student mixes 25 cm3 samples of dilute hydrochloric acid with different volumes of aqueous
sodium hydroxide.
In each case, the student measures the change in temperature to test if the reaction is
exothermic.
Which piece of apparatus is not needed?
A B C D
burette clock pipette thermometer
© UCLES 2016 0620/21/O/N/16

3
3 Information about the solubility of four solids, P, Q, R and S, is given in the table.
P Q R S
solubility in water dissolves insoluble insoluble dissolves
A student attempted to separate mixtures of these solids using the following method.
1 Add the mixture to a beaker of water and stir.

3 Crystallise one of the solids from the filtrate.
Which of the following mixtures could not be separated by this method?
A a mixture of P and R
B a mixture of Q and P
C a mixture of Q and R
D a mixture of R and S
4 The table shows information about atoms of three different elements.

element
chlorine 17 35 17 W 17
chlorine 17 X 17 19 17
argon Y 40 18 22 18
potassium 19 39 19 20 Z
W X Y Z
A 18 35 18 19
B 18 36 18 19
C 19 35 19 18
D 19 36 19 18

4
5 Metal P reacts with non-metal Q to form a compound.
Which process takes place and which type of compound is formed?
process type of compound
A electrons are transferred from P to Q covalent

B electrons are transferred from P to Q ionic
C electrons are transferred from Q to P covalent
D electrons are transferred from Q to P ionic
6 The structure of ethanoic acid is shown.
H O
H C C
H O H
Which diagram shows the arrangement of outer shell electrons in a molecule of ethanoic acid?
A B
H H
O O
H C C H C C
O H O H
H H
C D
H H
O O
H C C H C C
O H O H
H H
© UCLES 2016 0620/21/O/N/16

5
7 X is a solid at room temperature.
X has a high melting point.
Solid X conducts electricity.
Which diagram shows how the particles are arranged in solid X?
A B C D
– –
+ – +
+ + +
– – + –
– – + –
+ +
– – – + – +
– –
+ – +
+ + +
– + –
8 Benzene is a liquid with molecular formula C6H6.
Ethene is a gas with molecular formula C2H4.
A 1 mole of benzene and 1 mole of ethene contain the same number of atoms.
B 1 mole of benzene and 1 mole of ethene both have a volume of 24 dm3 at room temperature
and pressure.
C Both benzene and ethene have the same empirical formula.
D The number of carbon atoms in 0.5 moles of ethene is equal to the Avogadro constant.
9 Sodium hydrogencarbonate undergoes thermal decomposition as shown.
2NaHCO3 → Na2CO3 + CO2 + H2O
What is the maximum mass of sodium carbonate that can be made from 0.100 moles of
sodium hydrogencarbonate?
A 4.15 g B 5.30 g C 10.6 g D 21.2 g

6
10 Which apparatus could be used to electroplate an iron nail with copper?
A B key
+ – + – = copper sheet
= iron nail
C D
+ – + –
aqueous iron(II) sulfate
© UCLES 2016 0620/21/O/N/16

7
11 The diagram shows a simple cell.
voltmeter
V
metal X metal Y
electrolyte
Which two metals produce the highest reading on the voltmeter?
X Y
A magnesium copper
B magnesium iron
C zinc copper
D zinc iron
thermometer
anhydrous
copper(II) sulfate
water
Which row shows the temperature change and the type of reaction taking place?
A decrease endothermic
B decrease exothermic
C increase endothermic
D increase exothermic

8
13 The energy level diagram for a reaction is shown.
Ea products
energy
ΔH
reactants
Which statement is not correct for this energy level diagram?
A It could be the energy level diagram for the reaction when petrol is burnt.
B Less energy is released in bond forming than is needed for bond breaking.
C The activation energy, Ea, has a positive value.
D The energy change, ∆H, for the reaction is positive.
© UCLES 2016 0620/21/O/N/16

9
14 The rate of reaction between magnesium and excess dilute hydrochloric acid was followed by
measuring the mass of magnesium present at regular time intervals.
Two experiments were performed.
Both experiments used 0.1 g of magnesium ribbon. The acid in experiment 1 was less
concentrated than in experiment 2.
Which graph shows the results of the experiments?
A B
mass of mass of
magnesium magnesium
1 2
2 1
0 0
0 time 0 time
C D
2 1
mass of 1 mass of 2
magnesium magnesium
0 0
0 time 0 time
15 Which statement explains why coal dust forms an explosive mixture with air?
A Coal dust catalyses the explosion.

B Coal dust has a large surface area.
C Crushing coal increases the concentration of the coal.
D Crushing coal increases the temperature of the coal.

10
16 The following reversible reaction takes place in a closed vessel at constant temperature.
P(g) + Q(g) + R(g) S(g) + T(g)
When the system has reached equilibrium, more T is added.
After the addition of T, which substances increase in concentration?
A P, Q, R and S
B P and Q only
C P, Q and R only
D S only
17 Four ionic half-equations are shown.
1 Cu2+(aq) + 2e– → Cu(s)
2 2I–(aq) → I2(aq) + 2e–
3 Fe2+(aq) → Fe3+(aq) + e–
4 Cl 2(g) + 2e– → 2Cl –(aq)
A In equation 1, copper(II) ions are oxidised to copper.

B In equation 2, iodide ions are reduced to iodine.
C In equation 3, iron(II) ions are oxidised to iron(III) ions.

D In equation 4, chlorine is oxidised to chloride ions.
18 Germanium oxide is a white powder.
Germanium oxide reacts with concentrated hydrochloric acid.
Germanium oxide reacts with concentrated aqueous sodium hydroxide.
Germanium oxide does not dissolve when added to water.
Which type of oxide is germanium oxide?
A acidic
B amphoteric
C basic
D neutral
© UCLES 2016 0620/21/O/N/16

11
19 Hydrogen chloride gas reacts with water to produce an acidic solution. The equation for the
reaction is shown.
HCl + H2O → Cl – + H3O+
Which statement describes what happens during the reaction?
A The chloride ion is formed by accepting an electron from the water.

B The hydrogen chloride loses an electron to form the chloride ion.
C The water accepts a proton from the hydrogen chloride.
D The water donates a proton to the hydrogen chloride.
20 The apparatus shown is used to prepare aqueous copper(II) sulfate.
filter paper
stirrer
excess of solid X
solid X
Y aqueous
copper(II) sulfate
heat
What are X and Y?
X Y
A copper aqueous iron(II) sulfate

B copper(II) chloride sulfuric acid
C copper(II) oxide sulfuric acid
D sulfur aqueous copper(II) chloride

12
21 Information about some silver compounds is shown in the table.
compound formula solubility in water
silver carbonate Ag2CO3 insoluble

silver chloride AgCl insoluble
silver nitrate AgNO3 soluble
silver oxide Ag2O insoluble
Which equation shows a reaction which cannot be used to make a silver salt?
A AgNO3(aq) + HCl (aq) → AgCl (s) + HNO3(aq)
B Ag2O(s) + 2HNO3(aq) → 2AgNO3(aq) + H2O(l)
C Ag2CO3(s) + 2HNO3(aq) → 2AgNO3(aq) + H2O(l) + CO2(g)
D 2Ag(s) + 2HCl (aq) → 2AgCl (s) + H2(g)
22 What is not a property of Group I metals?
A They are soft and can be cut with a knife.

B They react when exposed to oxygen in the air.
C They produce an acidic solution when they react with water.
D They react rapidly with water producing hydrogen gas.
© UCLES 2016 0620/21/O/N/16

13
23 Four substances, P, Q, R and S, are tested as shown.
substance
test
P Q R S
gas given off gas given off
dilute hydrochloric
which ‘pops’ with which turns no reaction no reaction
acid added
a lighted splint limewater milky
dilute aqueous gas given off

sodium hydroxide which turns
added and no reaction no reaction damp, red litmus no reaction
warmed gently paper blue
What are P, Q, R and S?
P Q R S
A Mg Na2CO3 NH4Cl NaCl

B Mg NH4Cl Na2CO3 NaCl
C Mg Na2CO3 NaCl NH4Cl
D Na2CO3 Mg NaCl NH4Cl
24 Which statement about transition elements and their compounds is correct?
A All the transition elements have an oxidation state of +2 only.

B Aqueous solutions of the salts of transition elements are generally coloured.
C Transition elements change from metal to non-metal across the period.
D Transition elements can act as catalysts but their compounds cannot.

14
25 Impure iron from the blast furnace is converted to steel as shown.
oxygen
impure molten iron
Which statement about the process is correct?
A Acidic oxides are added to remove alkaline impurities.

B Coke is added as a reducing agent.
C Oxygen is blown in to oxidise the impure iron.
D The steel produced contains less carbon than the impure iron.
26 The ionic equations represent the reactions between four metals, P, Q, R and S, and solutions of
the salts of the same metals.
P + Q2+ → no reaction
R + P2+ → R2+ + P
Q + S2+ → Q2+ + S
S + P2+ → S2+ + P
S + R2+ → S2+ + R
S + Q2+ → no reaction
What is the correct order of reactivity of the metals?
most least
A P R S Q
B Q R S P
C Q S R P
D S Q P R
© UCLES 2016 0620/21/O/N/16

15
27 Aluminium is extracted by electrolysis.
From which ore is aluminium extracted and at which electrode is aluminium deposited during
electrolysis?
ore electrode
A bauxite negative
B bauxite positive
C cryolite negative
D cryolite positive
28 Zinc oxide can be reacted with carbon to produce zinc metal.
Which equation for this reaction is correct?
A 2ZnO + C → 2Zn + CO
B 2ZnO + 2C → 2Zn + 2CO2
C ZnO + C → Zn + CO
D ZnO + 2C → Zn + 2CO2
29 Air is a mixture of gases.
Which gas is present in the largest amount?
A argon
B carbon dioxide
C nitrogen
D oxygen


16
31 Underwater steel pipes can be protected from corrosion by attaching magnesium blocks to them.
Which equation represents the reaction that prevents corrosion?
A Fe → Fe2+ + 2e–
B Fe2+ → Fe3+ + e–
C Mg → Mg2+ + 2e–
D Mg2+ + 2e– → Mg
32 Ammonia is manufactured by the Haber process. The reaction is exothermic.
N2(g) + 3H2(g) 2NH3(g) ∆H = –92 kJ / mol
Which statement about the Haber process is correct?
A The reaction is irreversible and produces only one product.

B The reaction is reversible and produces less ammonia at high pressure.
C The reaction is reversible and produces less ammonia at high temperature.
D The reaction is slow because a catalyst is not used in the Haber process.
33 Sulfuric acid is manufactured by the Contact process.
The most important reaction takes place in the presence of a catalyst.
What are the reactants and the catalyst for this reaction?
reactants catalyst
A sulfur and oxygen vanadium(V) oxide

B sulfur dioxide and oxygen vanadium(V) oxide
C sulfur dioxide and steam iron
D sulfur trioxide and water platinum
© UCLES 2016 0620/21/O/N/16

17
34 Which box corresponds to limestone?
Does limestone contain carbon?
yes no
Does limestone burn? Does limestone burn?
yes no yes no
A B C D
35 Petroleum is an important fossil fuel.
Which row correctly describes petroleum?
type of substance composition

A compound mainly hydrocarbons
B compound only hydrogen and carbon
C mixture mainly hydrocarbons
D mixture only hydrogen and carbon
36 Butane reacts as shown.
catalyst
butane butene + hydrogen
and heat
What is this type of reaction?
A combustion
B cracking
C polymerisation
D reduction

18
37 Substance Z has the following characteristics.
1 It burns in an excess of oxygen to form carbon dioxide and water.

2 It is oxidised by air to form a liquid smelling of vinegar.
3 It reacts with carboxylic acids to form esters.
What is substance Z?
A ethane
B ethanoic acid
C ethanol
D ethyl ethanoate
38 Ethanol is manufactured by the catalytic addition of steam to ethene and by fermentation.
Which row shows an advantage and a disadvantage of using the catalytic addition of steam to
ethene compared to fermentation?
advantage disadvantage
A fast the product is impure

B fast uses non-renewable materials
C the product is pure slow
D uses renewable materials slow
39 The partial structure of addition polymer X is shown.
CH3 H CH3 H
C C C C
H CH3 H CH3
Which monomer is used to form polymer X?
A CH2=CH2
B CH3CH=CH2
C CH3CH=CHCH3
D CH3CH2CH=CH2
© UCLES 2016 0620/21/O/N/16

19
40 The diagram shows the partial structure of Terylene.
O O O
C O O C C O
From which pair of compounds is it made?
O O
A HO C C OH + HO OH
O O
B HO C OH + HO C OH
O O
C HO OH + HO C C OH
O O O O
D HO C C OH + HO C C OH
© UCLES 2016 0620/21/O/N/16

Group
© UCLES 2016
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
20
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/21/O/N/16
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/21
MARK SCHEME
Maximum Mark: 40
Published
Teachers.
components.

Question Question
Key Key
Number Number
1 C 21 D
2 B 22 C
3 C 23 A
4 B 24 B
5 B 25 D
6 C 26 C
7 A 27 A
8 D 28 C
9 B 29 C
10 A 30 B
11 A 31 C
12 D 32 C
13 A 33 B
14 A 34 B
15 B 35 C
16 C 36 B
17 C 37 C
18 B 38 B
19 C 39 C
20 C 40 A
© UCLES 2016
*3756670404*
CHEMISTRY 0620/31

Paper 3 Theory (Core) October/November 2016

1 hour 15 minutes

IB16 11_0620_31/3RP
2
1 The diagram shows part of the Periodic Table.
H
Li B C N O F Ne
Na Al Si P S Cl Ar
K Ca Cu Zn Br Kr
Answer the following questions using only the elements in the diagram.
Each element may be used once, more than once or not at all.
(a) Which element
(i) has a smaller proton number than lithium,
. ...................................................................................................................................... [1]
(ii) is formed at the cathode when a dilute solution of sulfuric acid is electrolysed,
. ...................................................................................................................................... [1]
(iii) has an oxide of the type XO2 which is used to bleach wood pulp,
. ...................................................................................................................................... [1]
(iv) forms ions which when tested with excess aqueous sodium hydroxide produce a white
precipitate,
. ...................................................................................................................................... [1]
(v) is extracted from bauxite?
. ...................................................................................................................................... [1]
© UCLES 2016 0620/31/O/N/16

3
(b) Mercury has several naturally-occurring isotopes. One of these is shown.

204
80 Hg
(i) What is the meaning of the term isotope?
. ............................................................................................................................................
. ...................................................................................................................................... [2]
204
(ii) How many neutrons are there in one atom of the isotope 80 Hg ?
. ...................................................................................................................................... [1]
204
(iii) How many protons are there in one atom of the isotope 80 Hg ?
. ...................................................................................................................................... [1]
(iv) Determine the number of electrons in the mercury(II) ion, Hg2+.
. ...................................................................................................................................... [1]
[Total: 10]

4
2 The bar charts compare the concentrations of the main ions in two samples of seawater, sample A
and sample B.
sample A sample B
20 20
15 15
concentration
concentration
in mg / dm3
in mg / dm3
10 10
5 5
0 0
Na+ Ca2+ K+ Mg2+ SiO32– Cl – HCO3– Na+ Ca2+ K+ Mg2+ SiO32– Cl – HCO3–
(a) Use the information in the bar charts to answer the following questions.
(i) Describe two differences in the composition of the seawater in sample A and sample B.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) Which positive ion has the lowest concentration in sample A?
. ...................................................................................................................................... [1]
(iii) Calculate the mass of sodium ions in 200 cm3 of sample B.

Show all your working. [1 dm3 = 1000 cm3]
mass = ...................... mg [2]
(b) Describe a test for sodium ions.
test . ............................................................................................................................................
result . .........................................................................................................................................
[2]
© UCLES 2016 0620/31/O/N/16

5
(c) River water contains small particles of clay. When these particles are viewed under a microscope
they show a random, jumpy motion even when the water is still.
What name is given to this type of movement?
.............................................................................................................................................. [1]
(d) Carbon dioxide dissolves in water to form a mixture which contains hydrogencarbonate ions
and hydrogen ions.
CO2(g) + H2O(l) HCO3–(aq) + H+(aq)
(i) What is the meaning of the symbol ?
. ...................................................................................................................................... [1]
(ii) The solution formed is slightly acidic.
Describe how you would use Universal Indicator paper to determine the pH of this solution.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(iii) Carbon dioxide is a greenhouse gas which causes climate change.
Explain how carbon dioxide contributes to climate change.
. ...................................................................................................................................... [1]
(iv) State the name of one other greenhouse gas and give one source of this gas.
gas . .....................................................................................................................................
source . ................................................................................................................................
[2]
[Total: 14]

6
3 Calcium is in Group II of the Periodic Table.
(a) Draw a diagram to show the electronic structure of an atom of calcium.
[2]
(b) Calcium is manufactured by the electrolysis of molten calcium chloride.
Complete the boxes in the diagram to show the
• anode,
• cathode,
• electrolyte.
calcium
forming
+
[2]
(c) Calcium reacts with water to form calcium hydroxide and a gas which ‘pops’ with a lighted
splint.
Complete the chemical equation for this reaction.
Ca + .......H2O → Ca(OH)2 + ...............

[2]
© UCLES 2016 0620/31/O/N/16

7
(d) Describe the manufacture and uses of lime (calcium oxide).

Include at least one relevant word equation relating to the manufacture or use of lime.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [4]
[Total: 10]

8
4 A porous pot has tiny holes in its walls which allow gases to move in or out of the pot.
A teacher filled a porous pot with green chlorine gas. The teacher then placed the pot in a large jar
of air. After 10 minutes, a green colour was seen outside the porous pot.
air
porous
chlorine pot
gas
at the start after 10 minutes
(a) Use the kinetic particle model of matter to explain this observation.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(b) A porous barrier can be used to separate uranium fluoride molecules containing different
isotopes of uranium.
(i) State the main use of the radioactive isotope 235U.
. ...................................................................................................................................... [1]
(ii) Give one medical use of radioactive isotopes.
. ...................................................................................................................................... [1]
(iii) The accurate relative atomic mass of uranium is 238.03.
Define the term relative atomic mass.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
© UCLES 2016 0620/31/O/N/16

9
(c) Chlorine reacts with potassium bromide to form bromine and potassium chloride.
(i) Complete the chemical equation for this reaction.
............... + 2KBr → Br2 + .......KCl

[2]
(ii) Give one use of chlorine.
. ...................................................................................................................................... [1]
(iii) Chlorine forms an oxide with the formula Cl 2O7.
Is this oxide an acidic or a basic oxide?

. ............................................................................................................................................
. ...................................................................................................................................... [1]
(iv) A teacher heated a test-tube containing anhydrous copper(II) chloride. A piece of damp
litmus paper was placed at the top of the test-tube.
litmus paper
anhydrous copper(II) chloride
heat
The anhydrous copper(II) chloride decomposed and chlorine was formed.
Describe the colour change of the litmus paper.
. ...................................................................................................................................... [1]
[Total: 12]

10
5 The table shows the properties of some steels.
percentage of relative melting point

steel ease of corrosion
carbon in the steel strength range / °C
A 1.0 8.0 1430–1460 corrodes easily
B 0.50 6.5 1430–1450 corrodes fairly easily
C 0.25 5.0 1410–1430 corrodes fairly easily
D 0.10 4.0 1440–1450 resistant to corrosion
(a) Use the information in the table to answer the following questions.
(i) What is the relationship between the percentage of carbon in the steel and its strength?
. ...................................................................................................................................... [1]
(ii) State whether there is a relationship between the percentage of carbon in the steel and its
melting point range.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(iii) Which steel would be best to use for making a bicycle chain?
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(b) Steel is an alloy.
Which one of the diagrams best represents an alloy?

Draw a ring around the correct answer.
Cr Fe Fe Fe Ni Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Ni Ni Ni Ni Ni
Fe Fe Cr Fe Ni Ni Ni Ni Fe Fe Fe Fe Ni Ni Ni Ni
Fe Fe Fe Fe Ni Cr Cr Cr Cr Cr Fe Fe Fe Fe Fe Ni Ni Ni Ni Ni
Fe Ni Fe Cr Fe Fe Fe Fe Fe Fe Fe Fe Ni Ni Ni Ni
A B C D
[1]
© UCLES 2016 0620/31/O/N/16

11
(c) High voltage electricity cables are made from aluminium with a steel core.
(i) Apart from conducting electricity, what is the purpose of the steel core?
. ...................................................................................................................................... [1]
(ii) Aluminium is a good electrical conductor.
Give one other use of aluminium and state a property of aluminium which makes it suitable
for this use.
use . .....................................................................................................................................
property ...............................................................................................................................
[2]
(d) Aluminium powder reacts with powdered iron(III) oxide. The equation for this reaction is shown.
2Al + Fe2O3 → Al 2O3 + 2Fe
(i) Which substance is oxidised in this reaction?

. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) The energy level diagram for this reaction is shown.
2Al + Fe2O3
energy
Al 2O3 + 2Fe
Is this reaction exothermic or endothermic?

. ............................................................................................................................................
. ...................................................................................................................................... [1]
[Total: 10]

12
6 (a) Describe the characteristic properties of acids.

In your answer you should refer to the reactions of acids with metals, bases, carbonates and
indicators.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]
(b) The table shows some properties of the first five members of the carboxylic acid homologous
series.
molecular melting point boiling point density

acid
formula / °C / °C in g / cm3
methanoic acid CH2O2 8 101 1.22
ethanoic acid C2H4O2 17 118 1.05
propanoic acid C3H6O2 –21 141 0.99
butanoic acid C4H8O2 –5 164 0.96
pentanoic acid C5H10O2 –34 0.93
(i) How does the density of the carboxylic acids vary with the number of carbon atoms in the
molecule?
. ...................................................................................................................................... [1]
(ii) Suggest a value for the boiling point of pentanoic acid.
. ...................................................................................................................................... [1]
(iii) Determine the state of ethanoic acid at 15 °C.

. ............................................................................................................................................
. ...................................................................................................................................... [2]
© UCLES 2016 0620/31/O/N/16

13
(iv) Draw the structure of the functional group present in carboxylic acids.
Show all of the atoms and all of the bonds.
[1]
(v) Calculate the relative molecular mass of butanoic acid.

Show all your working.
[2]
(c) Identify the following as either physical changes or chemical changes by writing either ‘physical’
or ‘chemical’ in the spaces provided.
The condensation of ethanoic acid vapour to liquid ethanoic acid is a ......................... change.
The reaction of sodium with ethanoic acid is a ......................... change.
The dissolving of a salt in water is a ......................... change.

[2]
[Total: 14]

14
7 The diagram shows the changes of state when sulfur is heated.
solid A liquid B sulfur

sulfur sulfur vapour
(a) Give the names of the changes of state labelled A and B.
A .................................................................................................................................................
B .................................................................................................................................................
[2]
(b) Describe the arrangement and motion of the particles in sulfur vapour.
arrangement ...............................................................................................................................
motion . .......................................................................................................................................
[2]
(c) Give one use of sulfur.
.............................................................................................................................................. [1]
(d) Some compounds of sulfur are found in coal.
Explain why the presence of sulfur in coal has an adverse effect on human health when the
coal is burnt.
....................................................................................................................................................
.............................................................................................................................................. [2]
© UCLES 2016 0620/31/O/N/16

15
(e) One of the compounds of sulfur in coal is thiophene.

The structure of thiophene is shown.
H H
C C
C C
H H
S
(i) Determine the formula of thiophene.
. ...................................................................................................................................... [1]
(ii) Thiophene can be made in the laboratory by heating ethyne, C2H2, with hydrogen sulfide,
H2S, in the presence of a catalyst.
What is the purpose of the catalyst?
. ...................................................................................................................................... [1]
(iii) When 2.6 g of ethyne react with excess hydrogen sulfide, 4.2 g of thiophene are formed.
Calculate the mass of thiophene formed when 15.6 g of ethyne react with excess hydrogen
sulfide.
[1]
[Total: 10]
© UCLES 2016 0620/31/O/N/16

Group
© UCLES 2016
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/31/O/N/16
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/31
Paper 3 Core Theory October/November 2016
MARK SCHEME
Maximum Mark: 80
Published
Teachers.
components.

Question Answer Mark
1(a)(i) H / hydrogen 1
1(a)(ii) H / hydrogen 1
1(a)(iii) S / sulfur 1
1(a)(iv) Ca / calcium 1
1(a)(v) Al / aluminium 1
1(b)(i) atoms 1
with the same number of protons but different number of neutrons 1
OR
atoms 1
of the same element with different number of neutrons 1
1(b)(ii) 124 1
1(b)(iii) 80 1
1(b)(iv) 78 1
© UCLES 2016
2(a)(i) any 2 from: 2

• more Na+ ions in sample B ORA
• more Cl– ions in sample B ORA
• more Mg2+ ions in sample B ORA
• more HCO3– ions in sample A ORA
• more Ca2+ ions in sample A ORA
• more K+ ions in sample A ORA
• more SiO32– ions in sample A ORA
2(a)(ii) Mg2+ 1
2(a)(iii) 2 mg = [2] 2
200
× (10) = [1]
1000
OR
0.2 × (10) = [1]
2(b) test: flame test / description of flame test 2

result: yellow (flame)
2(c) Brownian (motion) 1
2(d)(i) indicates a reversible reaction 1
2(d)(ii) dip (indicator) paper in solution / put (indicator paper) in solution 1

compare the colour with the (colour) chart / different colours represent different pH values 1
2(d)(iii) absorbs heat / absorbs infra-red radiation / causes global warming 1
2(d)(iv) gas: methane 1

source: gases from (digestion in) animals / swamps / decomposition of vegetation / rice paddy fields / fracking / 1
melting of permafrost /
© UCLES 2016
3(a) 2 electrons in the outer shell 1

inner shells correct (2, 8, 8) 1
3(b) 2
cathode
electrolyte
anode
3(c) H2 (on right) 1

2(H2O) (on left) 1
3(d) 4
manufacture (max = [2])
• limestone / calcium carbonate heated
• thermal decomposition
• heated in kiln / heated in current of air / coke for heating / carbon for heating
uses (max = [2])

• neutralise acidic waste / treating flue gases
• neutralise acidic soils
• steelmaking / removing impurities in iron
• (lime) mortar / cement / plaster / lime wash
• slaked lime / limewater
equation (max = [2])

• e.g. calcium carbonate → calcium oxide + carbon dioxide
• calcium oxide + acid → calcium salt + water
© UCLES 2016
4(a) any 3 from: 3

• diffusion
• particles move / motion of particles
• (movement is) random / in any direction / in all directions
• particles spread out / particles mix
• particles move from high to low concentration
4(b)(i) energy (production) / power (production) 1
4(b)(ii) any suitable use, e.g. treatment of cancer / tracer / thyroid function / sterilising (medical) instruments / 1
4(b)(iii) average mass of atoms (of an element) 1

(on a scale where) the 12C atom has a mass of (exactly) 12 (units) 1
4(c)(i) Cl2 (on left) 1

2(KCl) (on right) 1
4(c)(ii) any suitable use, e.g. sterilising / killing bacteria / swimming pools / bleach / 1
4(c)(iii) acidic because chlorine is a non-metal / acidic because chlorine is on the right of the Periodic Table 1
4(c)(iv) goes colourless / bleached / (goes) white 1
© UCLES 2016
5(a)(i) the more carbon, the higher the strength ORA 1
5(a)(ii) 1
(no) the melting point range does not increase regularly / the melting point range goes up and down / the melting
point range remains fairly constant
OR
(yes) the more carbon, the greater the melting point range / the difference between the higher and lower number is
greater with more carbon
OR
(yes) the average melting point range is higher the more carbon (except for D) / the general trend is for a higher
melting point range with more carbon
5(a)(iii) D because it is resistant to corrosion 1
5(b) A 1
5(c)(i) gives strength / so the wire does not break / so the wire does not sag / for support 1
5(c)(ii) use: any suitable use, e.g. food container / saucepan / aircraft body / 1
property: any suitable property related to the use, e.g.(food container) resistant to acidic foods / (saucepan) good 1
conductor of heat / (aircraft body) low density /
5(d)(i) Al / aluminium 1
it gains oxygen 1
5(d)(ii) exothermic because the reactants have more energy than the products / exothermic because the products have 1
less energy than the reactants
© UCLES 2016
6(a) 4
effect on indicator (max = [1])
• turn (blue) litmus red
• turn methyl orange red / pink
reaction with metals (max = [1])

• react with metals to produce hydrogen
• react with metals to form a salt
reaction with bases (max = [1])

• react with bases to form a salt and water
reaction with carbonates (max = [1])

• react with carbonates to form a salt and water
• react with carbonates to form carbon dioxide
one other effect / reaction (max = [1])

• e.g. have a sour taste / pH below 7 / another property selected from the bullet points above
6(b)(i) density decreases as the number of carbon atoms increases ORA 1
6(b)(ii) values between and including 170 (°C)–220 (°C) 1
6(b)(iii) solid 1
its melting point is above 15 °C / 15 °C is below its melting point 1
6(b)(iv) displayed structure of COOH group showing all of the atoms and all of the bonds 1
6(b)(v) 88 2
4 × C OR 8 × H OR 2 × O OR C = 48 OR O = 32 scores [1]
6(c) physical / chemical / physical 2
© UCLES 2016
7(a) A = melting / fusion 1

B = boiling / vaporisation 1
7(b) arrangement: irregular / random / no fixed position / no (fixed) arrangement 2

motion: rapid / fast / random
7(c) any suitable use, e.g. tyre manufacture / making sulfur dioxide / making sulfuric acid / pesticide / insecticide / 1
7(d) sulfur dioxide is formed 1

sulfur dioxide causes irritation of the throat (OR nose OR lungs OR eyes or skin) 1
7(e)(i) C4H4S 1
7(e)(ii) speeds up the rate of a reaction 1
7(e)(iii) 25.2 (g) 1
© UCLES 2016
*6396621448*
CHEMISTRY 0620/41

Paper 4 Theory (Extended) October/November 2016

1 hour 15 minutes

IB16 11_0620_41/3RP
2
1 The table gives some information about five substances.
electrical electrical
melting point boiling point solubility
substance conductivity conductivity
/ °C / °C in water
when molten when solid
F –97 65 very soluble does not conduct does not conduct
G 1600 2230 insoluble does not conduct does not conduct
H 801 1413 soluble conducts does not conduct
I –57 126 insoluble does not conduct does not conduct
J 1085 2562 insoluble conducts conducts
(a) Which substance in the table has ionic bonding?
.............................................................................................................................................. [1]
(b) Which substance in the table has a giant covalent structure?
.............................................................................................................................................. [1]
(c) Name a method you could use to separate a mixture of substance J and water.
.............................................................................................................................................. [1]
(d) Name a method you could use to obtain substance F from a mixture of substance F and water.
.............................................................................................................................................. [2]
(e) Describe how you could obtain a solid sample of substance H from a mixture of substance H
and substance G.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(f) Substance J is a metal.
Describe how substance J is able to conduct electricity when it is a solid.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 10]
© UCLES 2016 0620/41/O/N/16

3
2 Matter can exist as solid, liquid or gas. The arrows show some changes of state.
solid
A B
liquid gas
(a) Name the changes of state represented on the diagram.
(i) A .................................................................................................................................... [1]
(ii) B .................................................................................................................................... [1]
(iii) C .................................................................................................................................... [1]
(b) Explain why energy has to be supplied to turn a liquid into a gas.
....................................................................................................................................................
.............................................................................................................................................. [1]
(c) The diagrams represent the same number of particles of a gas in two containers, D and E,
which have different volumes. The two containers are at the same temperature.
D E
In which container will the pressure be higher? Explain your answer.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [1]
[Total: 5]

4
3 (a) Petroleum is a mixture of hydrocarbons. It is separated into useful fractions by fractional

distillation. This can be done using the fractionating column shown.
X
O
petroleum
(i) What happens to the petroleum at point X, before it enters the fractionating column?
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(ii) State two ways in which fraction O differs from fraction L.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(b) Most of the hydrocarbons obtained from petroleum are alkanes. The alkanes are an
homologous series of saturated hydrocarbons with the general formula CnH2n+2.
Give two characteristics, other than having the same general formula, of members of an
homologous series.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
© UCLES 2016 0620/41/O/N/16

5
(c) The alkane with the molecular formula C5H12 can exist as a number of structural isomers.
Draw the structures of two isomers with the formula C5H12.
[2]
(d) The alkane ethane has the structure shown.
H H
H C C H
H H
When a mixture of ethane and chlorine is exposed to ultraviolet light a substitution reaction
takes place.
Draw the structure of one organic product from this substitution reaction.
[1]

6
(e) Isoprene is a naturally occurring hydrocarbon.
(i) Explain how the name of isoprene suggests that it contains a C=C double bond.
. ...................................................................................................................................... [1]
(ii) A sample of isoprene had the following composition by mass: C, 88.24%; H, 11.76%.
Calculate the empirical formula of isoprene. Show all your working.
empirical formula = .............................. [3]
(iii) What additional information would be required to calculate the molecular formula of
isoprene?
. ...................................................................................................................................... [1]
[Total: 13]
4 (a) Ammonia, NH3, is made by reacting nitrogen with hydrogen in the Haber process.
(i) Write a chemical equation for the formation of ammonia in the Haber process.
. ...................................................................................................................................... [2]
(ii) Name the raw materials from which nitrogen and hydrogen are obtained.
nitrogen . ..............................................................................................................................
hydrogen . ............................................................................................................................
[2]
(iii) State the temperature and pressure used in the Haber process. Include the units.
temperature .........................................................................................................................
pressure . .............................................................................................................................
[2]
© UCLES 2016 0620/41/O/N/16

7
(b) Ammonia is also made when ammonium carbonate decomposes.
(NH4)2CO3(s) 2NH3(g) + H2O(g) + CO2(g)
The reaction is reversible and can reach a position of equilibrium.
The graph shows how the yield of ammonia at equilibrium changes with temperature and
pressure.
yield of
ammonia 300 °C
100 °C
pressure
(i) What is meant by the term equilibrium for a reversible reaction?
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) Using information from the graph, explain whether the reaction is endothermic or
exothermic.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(iii) State and explain the effect of increasing the pressure on the yield of ammonia in this
reaction.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
[Total: 12]

8
5 Copper(II) sulfate solution was electrolysed using the apparatus shown.
copper wire
carbon anode + – carbon cathode
bubbles of gas copper(II) sulfate

solution
(a) A gas was formed at the anode.
Identify this gas and give the test for this gas.
gas . ............................................................................................................................................
test . ............................................................................................................................................
result of test ................................................................................................................................

[3]
(b) During electrolysis, electricity passes through the copper(II) sulfate solution.
Solid copper(II) sulfate does not conduct electricity.
Explain both of these statements.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
© UCLES 2016 0620/41/O/N/16

9
(c) The electrolysis was repeated using copper electrodes in place of carbon electrodes. The ionic
half-equations for the reactions at the two electrodes are shown.
anode Cu(s) → Cu2+(aq) + 2e–
cathode Cu2+(aq) + 2e– → Cu(s)
(i) Which species is reduced during the electrolysis? Explain your answer.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) The masses of the copper electrodes changed during the electrolysis.
State how and explain why the masses of the two copper electrodes changed.
Use the ionic half-equations to help you.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
(iii) Explain why, during the electrolysis, the colour of the copper(II) sulfate solution does not
change.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [1]
[Total: 12]

10
6 Nylon, Terylene and proteins are all polymers.
(a) What is a polymer?
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) Proteins are natural polymers. Proteins are biodegradable.
(i) Name the type of linkage in proteins.
. ...................................................................................................................................... [1]
(ii) What is meant by the term biodegradable?
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(iii) Name another natural polymer.
. ...................................................................................................................................... [1]
© UCLES 2016 0620/41/O/N/16

11
(c) Nylon and Terylene are synthetic polymers.

The repeat unit of nylon can be shown as
O O
C C N N
H H
Terylene can be made from the monomers shown.
O O
H O O H H O C C O H
Draw a diagram to show the repeat unit of Terylene.
[3]
[Total: 9]

12
7 Calcium chloride can be made by reacting calcium carbonate with hydrochloric acid.
CaCO3(s) + 2HCl (aq) → CaCl 2(aq) + H2O(l) + CO2(g)
An excess of calcium carbonate was added to 50.0 cm3 of 0.500 mol / dm3 hydrochloric acid. The
solution was filtered to remove the excess calcium carbonate.
(a) How many moles of HCl were used in this reaction?
..................................... mol [2]
(b) Deduce the number of moles of carbon dioxide gas made in this reaction.
..................................... mol [1]
(c) Calculate the mass of carbon dioxide made in this reaction.
........................................ g [2]
(d) Calculate the volume, in dm3, of carbon dioxide made in this reaction at room temperature and
pressure (r.t.p.).
.................................... dm3 [1]
[Total: 6]
© UCLES 2016 0620/41/O/N/16

13
Question 8 starts on the next page.

14
8 Magnesium carbonate reacts with dilute hydrochloric acid.
MgCO3(s) + 2HCl (aq) → MgCl 2(aq) + H2O(l) + CO2(g)
An excess of magnesium carbonate pieces was added to dilute hydrochloric acid. The apparatus in
the diagram was used to measure the volume of gas produced. The total volume of gas collected
was recorded every 20 seconds.
bung
inverted
measuring cylinder
conical flask
dilute
hydrochloric water
magnesium carbonate
pieces acid trough
(a) The results obtained are shown on the graph.
120
100
80
total volume of
gas collected 60
/ cm3
40
20
0
0 100 200 300 400 500
time / s
(i) Describe how the rate of this reaction changed during the reaction. Explain why the rate
changed in this way.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [4]
© UCLES 2016 0620/41/O/N/16

15
(ii) The experiment was repeated using the same mass of powdered magnesium carbonate
with the same volume and concentration of dilute hydrochloric acid.
Explain how the initial rate of reaction and total volume of gas collected would compare to
the first experiment.
initial rate of reaction ...........................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
total volume of gas ..............................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
[4]
(b) A piece of magnesium ribbon was cleaned. The experiment was repeated using this clean
magnesium ribbon instead of magnesium carbonate.
Mg(s) + 2HCl (aq) → MgCl 2(aq) + H2(g)
This reaction is exothermic.

The rate of the reaction gradually increased over the first 2 minutes.
Explain why the rate of the reaction increased.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]
[Total: 13]
© UCLES 2016 0620/41/O/N/16

Group
© UCLES 2016
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/41/O/N/16
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/41
Paper 4 Extended Theory October/November 2016
MARK SCHEME
Maximum Mark: 80
Published
Teachers.
components.

1(a) H 1
1(b) G 1
1(c) filtration 1
1(d) fractional 1
distillation 1
1(e) add / mix / stir / dissolve / shake / heat with water 1

filter / decant 1
heat (filtrate) or (leave filtrate to) evaporate 1
1(f) electrons 1
(electrons) move / flow (throughout structure) 1
2(a)(i) melt(ing) 1
2(a)(ii) sublimation / sublime 1
2(a)(iii) condensing / condensation 1
2(b) overcome / break the attractive forces 1
2(c) E AND particles hit the walls (of the container) more often 1
© UCLES 2016
3(a)(i) heated / evaporated / boiled 1
3(a)(ii) any 2 from: 2

(O is) more viscous / thicker
(O is) darker
(O has) longer / bigger molecules / more carbon atoms
(O has a) higher boiling point OR melting point
(O is) less flammable
3(b) any 2 from: 2

similar / same chemical properties
same functional group
trend / pattern in physical properties
(neighbouring members) differ by CH2
common methods of preparation
3(c) any 2 structures from: 2

pentane
methylbutane
dimethylpropane
3(d) correct structure with any number from 1 to 6 of the hydrogen atoms replaced by chlorine atoms 1
3(e)(i) (ends in) ene 1
3(e)(ii) M1 88.24 / 12 AND 11.76 / 1 1

M2 7.353 / 7.353 (= 1) AND 11.76 / 7.353 = (1.6) 1
M3 C5H8 1
3(e)(iii) relative molecular mass 1
© UCLES 2016
4(a)(i) N2 + 3H2 ⇌ 2NH3 2

M1 formulae
M2 balancing
4(a)(ii) (nitrogen) air / atmosphere 1

(hydrogen) steam / water / hydrocarbons / natural gas 1
4(a)(iii) (temperature) answer in range 370–470 °C 1

(pressure) answer in range 150–300 atm 1
4(b)(i) M1 forward and reverse reactions (occur) 1

M2 amounts / moles / concentrations (of reagents and products) constant 1
OR
M2 rate of forward and reverse reactions equal
4(b)(ii) endothermic AND yield increases as temperature increases 1
4(b)(iii) M1 yield decreases (as pressure increases) 1

M2 because more moles / molecules (of gas) on the right 1
M3 so position of equilibrium moves left 1
© UCLES 2016
5(a) (gas) oxygen 1

(test) glowing splint 1
(result of test) relights 1
5(b) reference to ions / ionic 1

ions cannot move in solid OR are in fixed positions in solid 1
ions can move when in solution 1
5(c)(i) copper ions / Cu2+ 1

gain of electrons / oxidation number decreases 1
5(c)(ii) any 3 from: 3

anode decreases (in mass)
copper removed (from anode) / solid (copper from anode) becomes aqueous
cathode increases (in mass)
copper deposited / added / Cu2+ deposited as Cu (on cathode)
5(c)(iii) copper is both added and removed (at same rate) 1

OR
the concentration (of copper ions) does not change
6(a) large / big molecule 1

made from (many) monomers (joined together) 1
6(b)(i) amide / peptide 1
6(b)(ii) (can be) broken down 1

by microbes / bacteria 1
6(b)(iii) starch / cellulose / DNA / RNA / polysaccharides / 1
© UCLES 2016
6(c)(i) M1 at least one correct ester linkage between boxes 1

M2 at least two boxes shown and sufficient correct C and O atoms to make two correct ester linkages 1
M3 continuation bond(s) AND if more than one repeat unit is shown, the repeat unit must be correctly identified 1
7(a) 0.025
M1 50 / 1000 (=0.05) 1
M2 (0.05 × 0.5) = 0.025 1
7(b) 0.0125 1
7(c) 0.55
M1 44 1
M2 0.55 1
7(d) 0.3 1
© UCLES 2016
8(a)(i) any 4 from: 4

slowed down
acid became less concentrated OR fewer particles per unit volume
fewer collisions per second OR lower collision rate
(then the reaction) stopped
all the hydrochloric acid reacted

faster (reaction)
(powder has) larger surface area
more collisions per second OR higher collision rate
same volume of gas
amount / moles hydrochloric acid is not changed
8(b) any 5 from: 5

temperature increased
particles have more energy
(particles) move faster
more collisions per second OR higher collision rate
more particles have sufficient energy to react / activation energy
more of the collisions are successful
© UCLES 2016
CHEMISTRY 0620/51

*3546960466*
More material may be issued if required, without penalty, but this should not be necessary.
caution. Safety glasses should be provided.
where relevant.
C = corrosive MH = moderate hazard
HH = health hazard T = acutely toxic
F = flammable O = oxidising
N = hazardous to the aquatic environment
by email: info@cie.org.uk,
by phone: +44 1223 553554,
by fax: +44 1223 553558,
IB16 11_0620_51CI/3RP
2
For Question 1
(b) one stirring thermometer, –10 °C to +110 °C at 1 °C graduations
(c) one polystyrene cup and a 250 cm3 beaker
[C] (d) 100 cm3 of aqueous sodium hydroxide of concentration 1.0 mol / dm3, labelled solution N
[MH][N] (e) 100 cm3 of aqueous ammonia of concentration 1.0 mol / dm3, labelled solution O
[C] (f) 100 cm3 of aqueous nitric acid of concentration 2.0 mol / dm3, labelled nitric acid
(h) one 50 cm3 burette and funnel for filling burette
© UCLES 2016 0620/51/CI/O/N/16

3
For Question 2
(a) one stoppered tube containing 0.5 g of aluminium sulfate, Al 2(SO4)3.18H2O, labelled
solid P
[HH][N] (b) anhydrous cobalt(II) chloride paper
(c) one rack of five test-tubes and a stopper to fit
(d) one hard-glass test-tube
(e) apparatus for a flame test

One method is to dip a wooden splint into dilute hydrochloric acid and then into the solid,
followed by insertion into a blue flame.
(f) distilled water
(g) aqueous barium nitrate of concentration suitable to give a positive sulfate test
[MH] (h) dilute nitric acid of concentration 0.5 mol / dm3
[C] (i) aqueous sodium hydroxide of concentration 1.0 mol / dm3
[MH][N] (j) aqueous ammonia of concentration 1.0 mol / dm3
[MH][N] (k) aqueous silver nitrate of concentration suitable to give a positive halide test
(l) spatulas
(m) one 10 cm3 measuring cylinder
(n) one Bunsen burner and matches
(o) one test-tube holder
(p) teat pipettes
(q) splints
Note: Labels do not need to include concentrations.

4
© UCLES 2016 0620/51/CI/O/N/16

5

6
© UCLES 2016 0620/51/CI/O/N/16

7
The Supervisor is asked to carry out the experiments in Questions 1 and 2 and to record the
results on a spare copy of the Question Paper clearly labelled ‘Supervisor’s Results’. Failure to
enclose these results and this report form may lead to candidates being unavoidably penalised.

8
(a) any general difficulties encountered in preparing materials for the Practical Test;
(c) accidents involving apparatus or materials.
CIE on the normal Application for Special Consideration form.
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
© UCLES 2016 0620/51/CI/O/N/16

*4268017354*
CHEMISTRY 0620/51


1 hour 15 minutes

Practical notes are provided on pages 11 and 12.
Total
IB16 11_0620_51/3RP
2
1 You are going to investigate what happens when nitric acid reacts with aqueous solutions of two
different alkalis, solution N and solution O.
Read all the instructions carefully before starting the experiments.
Instructions
(a) Experiment 1
Use a measuring cylinder to pour 50 cm3 of solution N into the polystyrene cup provided. Put
the polystyrene cup into a 250 cm3 beaker for support. Measure the initial temperature of the
solution and record it in the first row of the table.
Fill the burette with nitric acid to the 0.0 cm3 mark.
Add 5.0 cm3 of nitric acid to solution N in the polystyrene cup and stir the solution.
Measure and record the maximum temperature of the solution in the table.
Add a further 5.0 cm3 of nitric acid to the polystyrene cup and stir the solution. Measure and
record the maximum temperature of the solution in the table.
Continue to add 5.0 cm3 portions of nitric acid to the polystyrene cup, until a total volume of
40 cm3 of nitric acid has been added. Stir after each addition and measure and record the
maximum temperatures in the table.
Pour the solution away and rinse the polystyrene cup.
volume of nitric acid maximum temperature of the

added / cm3 solution in the polystyrene cup / °C
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
[2]
© UCLES 2016 0620/51/O/N/16

3
(b) Experiment 2
Refill the burette with nitric acid.

Repeat Experiment 1 using solution O instead of solution N.
volume of nitric acid maximum temperature of the

added / cm3 solution in the polystyrene cup / °C
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
[2]

4
(c) Plot the results for Experiments 1 and 2 on the grid and draw two smooth line graphs.
40
30
maximum
temperature
of solution
/ °C
20
10
0 10 20 30 40
volume of nitric acid added / cm3

[4]
(d) Use your graph to estimate the maximum temperature of the solution when 13 cm3 of nitric acid
were added to 50 cm3 of solution N in Experiment 1.
.............................. °C [2]
© UCLES 2016 0620/51/O/N/16

5
(e) Name a suitable indicator that could be used in Experiment 1.
.............................................................................................................................................. [1]
(f) Solution N and solution O are the same concentration.
In which experiment is the temperature change greater? Suggest why the temperature change
is greater in this experiment.
....................................................................................................................................................
.............................................................................................................................................. [2]
(g) How would the results differ in Experiment 1 if 100 cm3 of solution N were used?
....................................................................................................................................................
.............................................................................................................................................. [1]
(h) Suggest why a polystyrene cup is used in these experiments and not a copper can.
.............................................................................................................................................. [1]
(i) State one source of error in the experiments. Suggest an improvement to reduce this source
of error.
source of error ............................................................................................................................
improvement . .............................................................................................................................
[2]
[Total: 17]

6
2 You are provided with solid P, which is a metallic salt.

Carry out the following tests on solid P, recording all of your observations at each stage.
tests on solid P
(a) Describe the appearance of solid P.
.............................................................................................................................................. [1]
(b) Use a spatula to divide solid P into three portions.
(i) test 1
Heat the first portion of solid P in a hard-glass test-tube.
Test any gases given off with cobalt(II) chloride paper.
Record your observations.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
(ii) test 2
Carry out a flame test on the second portion of solid P.
. ...................................................................................................................................... [1]
tests on a solution of P
Add about 10 cm3 of distilled water to the third portion of solid P in a test-tube. Stopper the test-tube
and shake it to dissolve solid P.
(c) Divide the solution into four equal portions in four test-tubes. Carry out the following tests.
(i) To the first portion of the solution, add several drops of aqueous sodium hydroxide.
Then add excess aqueous sodium hydroxide to the mixture.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
(ii) To the second portion of the solution, add excess aqueous ammonia.
. ...........................................................................................................................................
. ...................................................................................................................................... [1]
© UCLES 2016 0620/51/O/N/16

7
(iii) To the third portion of the solution, add a few drops of dilute nitric acid and about 1 cm3 of
. ...................................................................................................................................... [1]
(iv) To the fourth portion of the solution, add a few drops of dilute nitric acid and about 1 cm3 of
aqueous barium nitrate.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(d) Solid P contains a metal ion.
Suggest what the appearance of solid P in (a) tells you about the identity of the metal ion.
.............................................................................................................................................. [1]
(e) What does test 1 tell you about solid P?
.............................................................................................................................................. [1]
(f) What does test 2 tell you about solid P?
.............................................................................................................................................. [1]
(g) Identify solid P.
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 17]

8
3 Agri Limes are mixtures of calcium carbonate and calcium oxide. Farmers use Agri Limes on fields
to neutralise acidity.
Plan an investigation to find out which of two different Agri Limes, Q or R, will neutralise more acid.
You are provided with common laboratory apparatus and chemicals, including dilute nitric acid.
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
..................................................................................................................................................... [6]
[Total: 6]
© UCLES 2016 0620/51/O/N/16

9
BLANK PAGE
© UCLES 2016 0620/51/O/N/16

10
BLANK PAGE
© UCLES 2016 0620/51/O/N/16

11

Test for anions

produced


colourless
colourless solution
© UCLES 2016 0620/51/O/N/16

12
sulfur dioxide (SO2) turns acidified aqueous

potassium manganate(VII) from
© UCLES 2016 0620/51/O/N/16

CHEMISTRY 0620/51
MARK SCHEME
Maximum Mark: 40
Published
Teachers.
components.

1(a) table of results for Experiment 1 1

initial and other temperature boxes completed correctly and results comparable to supervisor’s and
Experiment 1 maximum greater than Experiment 2 maximum 1
1(b) table of results for Experiment 2 1

initial and other temperature boxes completed correctly and comparable to supervisor’s and temperatures stop
rising 1
1(c) all points correctly plotted 2

best-fit smooth line graphs 1
labels 1
1(d) value from graph 1

shown clearly 1
1(e) phenolphthalein / litmus / suitable named indicator 1
1(f) Experiment 1 1
solution N is a stronger acid / has a higher pH 1
1(g) measured results / temperature changes / results would be smaller 1

OR
larger / double volume needed to reach same temperature changes
1(h) polystyrene is an insulator / copper is a (good) conductor 1
1(i) source of error: heat losses / using a measuring cylinder 1

improvement: lag / insulate / use burette; 1
© UCLES 2016
2(a) white crystals 1
2(b)(i) melts / liquefies / dissolves / bubbles 1

condensation / drops of liquid 1
cobalt(II) chloride paper turns colourless / light pink 1
2(b)(ii) no change / colour 1
2(c)(i) white 1
precipitate 1
dissolves / clears 1
2(c)(ii) white precipitate 1
2(c)(iii) no reaction / no change 1
2(c)(iv) white 1
precipitate 1
2(d) not a transition element (cation) 1
2(e) hydrated / contains water 1
2(f) it is not any named metal that gives a positive flame test 1
2(g) aluminium 1
sulfate 1
© UCLES 2016
3 6
method adding Agri Lime to acid
add weighed amount / known mass of Agri Lime Q
to a known volume of acid
with a named indicator added to the acid
until the indicator changes colour
note the mass of Agri Lime Q added
repeat with Agri Lime R
conclusion, e.g. ‘the experiment using the smaller amount of Agri Lime is better’
OR
method adding acid to Agri Lime
use weighed amount / known mass of Agri Lime Q
add acid to it gradually / from a burette
note volume of acid added
conclusion, e.g. ‘the experiment using the larger volume of acid is better’
© UCLES 2016
*0345891151*
CHEMISTRY 0620/61


1 hour

IB16 11_0620_61/3RP
2
1 The diagram shows the apparatus used to electrolyse dilute sulfuric acid.
oxygen hydrogen
dilute
platinum ............................
sulfuric acid
+ –
(a) Complete the box to show the role of the platinum. [1]
(b) Give one observation made during this electrolysis.
.............................................................................................................................................. [1]
(c) (i) Compare the volumes of oxygen and hydrogen produced.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) Which substance breaks down to form these gases?
. ...................................................................................................................................... [1]
(d) Give one test to distinguish between oxygen and hydrogen.
test . ............................................................................................................................................
result with oxygen . .....................................................................................................................
result with hydrogen ...................................................................................................................

[2]
[Total: 7]
© UCLES 2016 0620/61/O/N/16

3
2 A student investigated what happened when dilute nitric acid reacted with aqueous solutions of two
different alkalis, solution N and solution O.
(a) Experiment 1
A measuring cylinder was used to pour 50 cm3 of solution N into a polystyrene cup. The initial
temperature of the solution was measured.
A burette was filled with nitric acid to the 0.0 cm3 mark.
5.0 cm3 of nitric acid were added to solution N in the polystyrene cup and the solution stirred.
The maximum temperature of the solution was measured.
A further 5.0 cm3 of nitric acid were added to the polystyrene cup and the solution stirred. The
maximum temperature of the solution was measured.
The student continued to add 5.0 cm3 portions of nitric acid to the polystyrene cup, until a total
volume of 40 cm3 of nitric acid had been added. After each addition, the solution was stirred
and the maximum temperature measured.

4
Use the thermometer diagrams to record the maximum temperatures in the table.
volume of nitric acid

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0
added / cm3
30 30 35 35 35 40 35 35 35
thermometer
25 25 30 30 30 35 30 30 30
diagram
20 20 25 25 25 30 25 25 25
maximum temperature
of the solution in the
polystyrene cup / °C
[2]
(b) Experiment 2
Experiment 1 was repeated using solution O instead of solution N.

Use the thermometer diagrams to record the maximum temperatures in the table.
volume of nitric acid

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0
added / cm3
30 30 30 30 30 30 30 30 30
thermometer
25 25 25 25 25 25 25 25 25
diagram
20 20 20 20 20 20 20 20 20
maximum temperature
of the solution in the
polystyrene cup / °C
[2]
© UCLES 2016 0620/61/O/N/16

5
(c) Plot the results for Experiments 1 and 2 on the grid and draw two smooth line graphs.
35
30
maximum
temperature
of solution
/ °C 25
20
15
0 10 20 30 40
volume of nitric acid added / cm3

[4]
(d) Use your graph to estimate the maximum temperature of the solution when 13 cm3 of nitric acid
were added to 50 cm3 of solution N in Experiment 1.
.............................. °C [2]
(e) Name a suitable indicator that could be used in Experiment 1.
.............................................................................................................................................. [1]

6
(f) Solution N and solution O were the same concentration.
In which experiment is the temperature change greater? Suggest why the temperature change
is greater in this experiment.
....................................................................................................................................................
.............................................................................................................................................. [2]
(g) How would the results differ in Experiment 1 if 100 cm3 of solution N were used?
....................................................................................................................................................
.............................................................................................................................................. [1]
(h) Suggest why a polystyrene cup was used in these experiments and not a copper can.
.............................................................................................................................................. [1]
(i) State one source of error in the experiments. Suggest an improvement to reduce this source
of error.
source of error ............................................................................................................................
improvement . .............................................................................................................................
[2]
[Total: 17]
© UCLES 2016 0620/61/O/N/16

7
3 Solid P, which is an aluminium salt, was analysed.

The tests on solid P, and some of the observations, are shown.
tests on solid P
(a) test 1
Solid P was divided into three portions. The first portion of solid P was heated.
condensation formed on the sides of the test-tube

observations ............................................................................................................................
Any gases given off were tested with cobalt(II) chloride paper.
cobalt(II) chloride paper turned from blue to pink

observations ............................................................................................................................
What does test 1 tell you about solid P?
.............................................................................................................................................. [1]
(b) test 2
A flame test was carried out on the second portion of solid P.
observations ......................................................................................................................... [1]
tests on a solution of P
Distilled water was added to the rest of solid P in a test-tube and shaken to dissolve.
(c) The solution was divided into four equal portions in four test-tubes. The following tests were
carried out.
(i) test 3
Several drops of aqueous sodium hydroxide were added to the first portion of the solution.
Excess aqueous sodium hydroxide was then added to the mixture.
observations ........................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]

8
(ii) test 4
Several drops of aqueous ammonia were added to the second portion of the solution.
Excess aqueous ammonia was then added to the mixture.
observations ........................................................................................................................
. ...................................................................................................................................... [2]
Two further tests were carried out and the following observations made.
tests on a solution of P observations
test 5
Dilute nitric acid and aqueous silver nitrate were no visible reaction
added to the third portion of the solution.
test 6
Dilute nitric acid and aqueous barium nitrate white precipitate formed
were added to the fourth portion of the solution.
(d) What does test 5 tell you about solid P?
.............................................................................................................................................. [1]
(e) Identify solid P.
.............................................................................................................................................. [1]
(f) Describe the appearance of solid P.
.............................................................................................................................................. [1]
[Total: 10]
© UCLES 2016 0620/61/O/N/16

9
4 Agri Limes are mixtures of calcium carbonate and calcium oxide. Farmers use Agri Limes on fields
to neutralise acidity.
Plan an investigation to find out which of two different Agri Limes, Q or R, will neutralise more acid.
You are provided with common laboratory apparatus and chemicals, including dilute nitric acid.
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
..................................................................................................................................................... [6]
[Total: 6]

10
BLANK PAGE
© UCLES 2016 0620/61/O/N/16

11
BLANK PAGE
© UCLES 2016 0620/61/O/N/16

12
BLANK PAGE
© UCLES 2016 0620/61/O/N/16

CHEMISTRY 0620/61
MARK SCHEME
Maximum Mark: 40
Published
Teachers.
components.

1(a) electrodes 1
1(b) bubbles / fizz / effervescence 1
1(c)(i) more hydrogen 1

twice as much hydrogen / half as much oxygen 1
1(c)(ii) water 1
1(d) lighted splint

no effect / brighter light for oxygen 1
‘pops’ for hydrogen 1
OR
glowing splint
relights for oxygen 1
no effect for hydrogen 1
© UCLES 2016
2(a) table of results for Experiment 1 2

all temperature boxes completed correctly
22, 24, 26, 28, 30, 31, 30, 29, 28
2(b) table of results for Experiment 2 2

initial and other temperature boxes completed correctly
20, 21, 22, 23, 24, 25, 24, 23, 22
2(c) all points correctly plotted 2

best-fit smooth line graphs 1
labels 1
2(d) value from graph (27 °C) 1

shown clearly 1
2(e) phenolphthalein / litmus / suitable named indicator 1
2(f) Experiment 1 / solution N 1

solution N is a stronger acid / has a higher pH 1
2(g) measured results / temperature changes / results would be smaller 1

OR
larger / double volume needed to reach same temperature changes
2(h) polystyrene is an insulator / copper is a (good) conductor 1
2(i) source of error: heat losses / using a measuring cylinder 1

improvement: lag or insulate / use burette 1
© UCLES 2016
3(a) water present / hydrated 1
3(b) no change / colour 1
3(c)(i) white 1
precipitate 1
dissolves 1
3(c)(ii) white precipitate 1

no change 1
3(d) not a halide 1
3(e) (aluminium) sulfate 1
3(f) white (crystals) 1
© UCLES 2016
4 6
method adding Agri Lime to acid
add weighed amount / known mass of Agri Lime Q
to a known volume of acid
note the mass of Agri Lime Q added
conclusion, e.g. ‘the experiment using the smaller amount of Agri Lime is better’
OR
method adding acid to Agri Lime
use weighed amount / known mass of Agri Lime Q
add acid to it gradually / from a burette
note volume of acid added
conclusion, e.g. ‘the experiment using the larger volume of acid is better’
© UCLES 2016
CHEMISTRY 0620/11
Paper 1 Multiple Choice (Core) May/June 2016
45 Minutes
Soft clean eraser
*0022143872*

IB16 06_0620_11/4RP
2
1 In which changes do the particles move further apart?
W X
gas liquid solid
Y Z
A W and X B W and Z C X and Y D Y and Z
2 A sample of a dye is investigated by chromatography.
A line is drawn across a piece of chromatography paper and a spot of the dye is placed on it.
The paper is placed in water.
chromatography
paper
spot of dye line

water
what is used to
position of spot
draw the line
A ink above the level of the water

B ink below the level of the water
C pencil above the level of the water
D pencil below the level of the water
3 One of the instructions for an experiment reads as follows.
Quickly add 50 cm3 of acid.
What is the best piece of apparatus to use?
A a burette
B a conical flask
C a measuring cylinder
D a pipette
© UCLES 2016 0620/11/M/J/16

3
4 Diamond and graphite are macromolecules.
Which statement about diamond and graphite is not correct?
A They are giant structures with high melting points.

B They are non-conductors of electricity.
C They contain only atoms of a non-metal.
D They have covalent bonds between the atoms.
5 The table shows the electronic structure of four atoms.
atom electronic structure
W 2,8,1
X 2,8,4
Y 2,8,7
Z 2,8,8
Which two atoms combine to form a covalent compound?
A W and X B W and Y C X and Y D X and Z
6 An aluminium atom has a nucleon number of 27 and a proton number of 13.
How many neutrons does this aluminium atom contain?
A 13 B 14 C 27 D 40
7 What happens when a bond is formed between a green gaseous element and a soft metallic
element?
A The gas atoms gain an electron.

B The gas atoms lose an electron.
C The metal atoms gain an electron.
D The two elements share a pair of electrons.
8 The equation shows the reaction between magnesium and sulfuric acid.
[Ar: H, 1; O, 16; Mg, 24; S, 32]
In this reaction, which mass of magnesium sulfate is formed when 6 g of magnesium react with
excess sulfuric acid?
A 8 B 24 C 30 D 60

4
plastic coating
metal core

10 When substance X is electrolysed, the amount of gases P and Q formed is shown.
P Q
substance X
– +
A concentrated aqueous sodium chloride

B concentrated hydrochloric acid
C dilute sulfuric acid
D molten lead(II) bromide
© UCLES 2016 0620/11/M/J/16

5
11 The energy level diagram for the reaction between sodium hydrogen carbonate and dilute
hydrochloric acid is shown.
sodium chloride + water +

carbon dioxide
energy
sodium hydrogen carbonate +
dilute hydrochloric acid
Which row correctly describes the type of reaction and the energy of the reactants and products?
energy of the reactants

type of reaction
and products
A endothermic the products have more

energy than the reactants
B endothermic the reactants have more

energy than the products
C exothermic the products have more

energy than the reactants
D exothermic the reactants have more

energy than the products
12 The diagram shows some properties that substances may have.
To which labelled part of the diagram does 235U belong?
used as
compound A an energy
source
C
B D
radioactive

6
13 A liquid X reacts with solid Y to form a gas.
Which two diagrams show suitable methods for investigating the rate (speed) of the reaction?
1 2
cotton wool cotton wool
X X
Y Y
balance
3 4
stopper stopper
X X
Y Y
balance
© UCLES 2016 0620/11/M/J/16

7
14 An experiment, S, is carried out to measure the volume of hydrogen produced when excess dilute
sulfuric acid is added to zinc.
A second experiment, T, is carried out using the same mass of zinc but under different
conditions.
The results of the two experiments are shown.
total volume S
of hydrogen
T
0
0 time
Which changes in the conditions between experiments S and T give curve T?
addition of the zinc is in large

a catalyst pieces not powdered
A
B
C
D
15 Aluminium reacts with iron(III) oxide as shown.
iron(III) oxide + aluminium → iron + aluminium oxide
Which statement about this reaction is correct?
A Aluminium is oxidised.
B Aluminium oxide is reduced.
C Iron(III) oxide is oxidised.

D Iron is oxidised.
16 Which reaction is reversible?
A Cu + ZnSO4 → CuSO4 + Zn
B CuO + H2SO4 → CuSO4 + H2O
D CuSO4.5H2O → CuSO4 + 5H2O

8
17 Which statements are properties of an acid?

1 2
A
B
C
D
Which element forms an acidic oxide?
A B C
D
19 A method used to make copper(II) sulfate crystals is shown.
1 Place dilute sulfuric acid in a beaker.

2 Warm the acid.
3 Add copper(II) oxide until it is in excess.

5 Evaporate the filtrate until crystals start to form.
6 Leave the filtrate to cool.
What are the purposes of step 3 and step 4?
step 3 step 4
A to ensure all of the acid has reacted to obtain solid copper(II) sulfate
B to ensure all of the acid has reacted to remove excess copper(II) oxide
C to speed up the reaction to obtain solid copper(II) sulfate
D to speed up the reaction to remove excess copper(II) oxide
© UCLES 2016 0620/11/M/J/16

9
20 The results of two tests on solid X are shown.
test observation
aqueous sodium hydroxide added green precipitate formed

acidified silver nitrate added yellow precipitate formed
What is X?
A copper(II) chloride
B copper(II) iodide
C iron(II) chloride
D iron(II) iodide
21 Where in the Periodic Table is the metallic character of the elements greatest?
left or right at the top or bottom

side of a period of a group
A left bottom
B left top
C right bottom
D right top
22 Some properties of four elements, P, Q, R and S, are shown in the table.
Two of these elements are in Group I of the Periodic Table and two are in Group VII.
physical state at
element reaction with water
room temperature
P reacts vigorously solid

Q does not react with water solid
R reacts explosively solid
S dissolves giving a coloured solution liquid
A P is below R in Group I.
B Q is above R in Group I.
C Q is below S in Group VII.
D R is below S in Group VII.

10
23 Which of the following could be a transition element?
melting point density in electrical

colour
in °C g / cm3 conductor
A 114 4.9 purple no

B 659 2.7 grey yes
C 1677 4.5 grey yes
D 3727 2.3 black yes
24 Two statements about argon are given.

1 Argon has a full outer shell of electrons.
2 Argon is very reactive and is used in lamps.
Which is correct?

25 Three students, X, Y and Z, were told that solid P reacts with dilute acids and also conducts
electricity.
The table shows the students’ suggestions about the identity of P.
X Y Z
copper iron graphite
Which of the students are correct?
A X, Y and Z B X only C Y only D Z only
© UCLES 2016 0620/11/M/J/16

11
26 W, X and Y are metals, one of which is copper and one of which is iron.
• W has a coloured oxide which can be reduced by carbon.
• X has a black oxide and is also found in nature as a pure metal.
• Y has an oxide which cannot be reduced by carbon.
Which metal is the most reactive and what is the possible identity of W?
most reactive possible identity

metal of W
A X Cu
B X Fe
C Y Cu
D Y Fe
27 Tin is a metal that is less reactive than iron and is extracted from its ore cassiterite, SnO2.
Which statements about tin are correct?
1 Tin can be extracted from cassiterite using carbon.

2 Tin does not conduct electricity.
3 Tin is hard and shiny.
A Aluminium is used in the manufacture of aircraft because of its strength and high density.
B Copper is used in electrical wiring because of its strength and high density.
C Mild steel is used in the manufacture of car bodies because of its strength and resistance to
corrosion.
D Stainless steel is used in the construction of chemical plant because of its strength and
resistance to corrosion.

12
29 The diagram shows an experiment to investigate how paint affects the rusting of iron.
P Q
iron painted iron
air
water
What happens to the water level in tubes P and Q?
tube P tube Q
A falls rises
B no change rises
C rises falls
D rises no change
atmosphere
planet
The table shows the composition of its atmosphere.
carbon dioxide 4
nitrogen 72
oxygen 24

D nitrogen only
© UCLES 2016 0620/11/M/J/16

13
31 Water was added to separate samples of anhydrous cobalt(II) chloride and anhydrous
copper(II) sulfate.
Which row describes the colour changes that take place in these reactions?
cobalt(II) chloride copper(II) sulfate
A blue to pink blue to white

B blue to pink white to blue
C pink to blue blue to white
D pink to blue white to blue
32 Which pollutant found in air does not have an effect on respiration?
A carbon monoxide
B lead compounds
C oxides of nitrogen
D sulfur dioxide
33 A farmer’s soil is very low in both nitrogen (N) and phosphorus (P).
Which fertiliser would improve the quality of this soil most effectively?
percentage
nitrogen (N) phosphorus (P) potassium (K)
A 11 11 27
B 12 37 10
C 28 10 10
D 31 29 9
34 When limestone is heated it forms lime (calcium oxide) and carbon dioxide.
CaCO3(s) → CaO(s) + CO2(g)
A Carbon dioxide is a greenhouse gas which may contribute to climate change.

B Slaked lime is used to neutralise industrial waste.
C The lime can be used to treat alkaline soil.
D This reaction is an example of thermal decomposition.

14
35 The diagram shows the separation of petroleum into fractions.
gasoline
petroleum Z
bitumen
What could X, Y and Z represent?
X Y Z
A diesel oil lubricating fraction paraffin

B lubricating fraction diesel oil paraffin
C paraffin lubricating fraction diesel oil
D paraffin diesel oil lubricating fraction
36 Which of the compounds shown are in the same homologous series?
1 CH3OH
2 CH3CH2OH
3 CH3COOH
4 CH3CH2CH2OH
37 Compound Q decolourises bromine water.
Compound Q has two carbon atoms in each molecule.
Which statement about compound Q is correct?
A It contains carbon-hydrogen double bonds.

B It has six hydrogen atoms per molecule.
C It has two carbon-carbon double bonds.
D It is produced by cracking alkanes.
© UCLES 2016 0620/11/M/J/16

15
38 What is used in the production of ethanol from ethene?
A hydrogen and oxygen

B oxygen only
C steam
D yeast
39 Ethene forms an addition polymer as shown.
H H H H H H H H
...... + C C + C C + ...... ...... C C C C ......
H H H H H H H H
Which terms describe this polymer?
A a saturated compound called poly(ethane)

B a saturated compound called poly(ethene)
C an unsaturated compound called poly(ethane)
D an unsaturated compound called poly(ethene)
40 The diagram shows a molecule of an organic compound W.
H O
H C C
H OH
A A solution of W in water has a pH greater than pH 7.

B A solution of W in water reacts with sodium hydroxide solution.
C When copper(II) carbonate is added to a solution of W in water, a gas is produced.

D When magnesium is added to a solution of W in water, a gas is produced.
© UCLES 2016 0620/11/M/J/16

Group
© UCLES 2016
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
16
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/11/M/J/16
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/11
MARK SCHEME
Maximum Mark: 40
Published
Teachers.
Cambridge is publishing the mark schemes for the May/June 2016 series for most Cambridge IGCSE®,
Cambridge International A and AS Level components and some Cambridge O Level components.

Question Question
Key Key
Number Number
1 D 21 A
2 C 22 C
3 C 23 C
4 B 24 C
5 C 25 C
6 B 26 D
7 A 27 C
8 C 28 D
9 B 29 D
10 C 30 A
11 A 31 B
12 D 32 B
13 D 33 D
14 C 34 C
15 A 35 D
16 D 36 B
17 D 37 D
18 C 38 C
19 B 39 B
20 D 40 A

CHEMISTRY 0620/21
Paper 2 Multiple Choice (Extended) May/June 2016
45 Minutes
Soft clean eraser
*6622954837*

IB16 06_0620_21/4RP
2
1 The rate of diffusion of two gases, methane, CH4, and ethene, C2H4, is measured using the
apparatus shown.
constant
pressure
applied metal foil – gas
gas syringe gas escapes through
small hole in the foil
Which gas diffuses faster and why?
gas that
reason
diffuses faster
A ethene Ethene molecules are heavier and so move faster.
B ethene Ethene molecules have a double bond which makes them

more reactive.
C methane Methane molecules are lighter and so move faster.
D methane Methane molecules are smaller so they can get out of the
small hole more easily.
2 A sample of a dye is investigated by chromatography.
A line is drawn across a piece of chromatography paper and a spot of the dye is placed on it.
The paper is placed in water.
chromatography
paper
spot of dye line

water
what is used to
position of spot
draw the line
A ink above the level of the water

B ink below the level of the water
C pencil above the level of the water
D pencil below the level of the water
© UCLES 2016 0620/21/M/J/16

3
3 The paper chromatogram below was obtained from four different dyes.
Which dye has an Rf value of 0.7?
solvent front
baseline
A B C D
4 Which statements about isotopes of the same element are correct?
1 They are atoms which have the same chemical properties because they have the
same number of electrons in their outer shell.
2 They are atoms which have the same number of electrons and neutrons but
different numbers of protons.
3 They are atoms which have the same number of electrons and protons but different
numbers of neutrons.
5 The table shows the electronic structure of four atoms.
atom electronic structure
W 2,8,1
X 2,8,4
Y 2,8,7
Z 2,8,8
Which two atoms combine to form a covalent compound?
A W and X B W and Y C X and Y D X and Z

4
6 Which statement describes the attractive forces between molecules (intermolecular forces)?
A They are strong covalent bonds which hold molecules together.

B They are strong ionic bonds which hold molecules together.
C They are weak forces formed between covalently-bonded molecules.
D They are weak forces which hold ions together in a lattice.
7 The diagram represents the general structure of a solid Z.
+ –
+ –
+ –
– –
+ + –
+
– – –
+ + +
What is Z?
A aluminium
B iodine
C silicon dioxide
D sulfur
8 A compound, X, contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen by mass.
The relative molecular mass, Mr, of X is 60.
What is the molecular formula of X?
A CH2O B CH4O C C2H4O D C2H4O2
9 25 cm3 of 0.1 mol / dm3 hydrochloric acid exactly neutralise 20 cm3 of aqueous sodium hydroxide.
The equation for this reaction is:
NaOH + HCl → NaCl + H2O
What is the concentration of the sodium hydroxide solution?
A 0.080 mol / dm3

B 0.800 mol / dm3
C 0.125 mol / dm3
D 1.25 mol / dm3
© UCLES 2016 0620/21/M/J/16

5
10 Which reactions could take place at the anode during electrolysis?
1 4OH–(aq) → 2H2O(I) + O2(g) + 4e–
2 2Cl –(aq) → Cl 2(g) + 2e–
3 Cu2+(aq) + 2e– → Cu(s)
4 2H+(aq) + 2e– → H2(g)
11 The diagram shows some properties that substances may have.
To which labelled part of the diagram does 235U belong?
used as
compound A an energy
source
C
B D
radioactive
12 The diagram shows a simple cell.
voltmeter
zinc electrode copper electrode
electrolyte
Which statement about the process occurring when the cell is in operation is correct?
A Cu2+ ions are formed in solution.

B Electrons travel through the solution.
C The reaction Zn → Zn2+ + 2e– occurs.

D The zinc electrode increases in mass.

6
13 Hydrogen burns exothermically in oxygen.
The equation for the reaction is:
2H2 + O2 → 2H2O
The table shows the bond energies involved.
bond bond energy in kJ / mol
H–H 436
O=O 498
O–H 464
What is the energy given out during the reaction?
A –3226 kJ / mol
B –884 kJ / mol
C –486 kJ / mol
D –442 kJ / mol
© UCLES 2016 0620/21/M/J/16

7
14 A liquid X reacts with solid Y to form a gas.
Which two diagrams show suitable methods for investigating the rate (speed) of the reaction?
1 2
cotton wool cotton wool
X X
Y Y
balance
3 4
stopper stopper
X X
Y Y
balance
15 Which statements explain why increasing temperature increases the rate of a chemical reaction?
1 Heat makes the molecules move faster and collide more often.
2 Heat makes the molecules collide with more energy so they are more likely to react.
3 Increasing temperature lowers the activation energy for the reaction.

8
16 Steam reacts with carbon in an endothermic reaction.
C(s) + H2O(g) CO(g) + H2(g)
Which conditions of temperature and pressure would give the largest yield of hydrogen?
A high high
B high low
C low high
D low low
17 Which equation represents a reduction reaction?
A Fe2+ + e– → Fe3+
B Fe2+ → Fe3+ + e–
C Fe3+ + e– → Fe2+
D Fe3+ → Fe2+ + e–
18 Which statements are properties of an acid?

1 2
A
B
C
D
19 Which row describes whether an amphoteric oxide reacts with acids and bases?
reacts with acids reacts with bases
A no no
B no yes
C yes no
D yes yes
© UCLES 2016 0620/21/M/J/16

9
20 Which substance reacts with dilute sulfuric acid to form a salt that can be removed from the
resulting mixture by filtration?
A aqueous barium chloride

B aqueous sodium hydroxide
C copper
D copper(II) carbonate
21 Where in the Periodic Table is the metallic character of the elements greatest?
left or right at the top or bottom

side of a period of a group
A left bottom
B left top
C right bottom
D right top
22 Some properties of four elements, P, Q, R and S, are shown in the table.
Two of these elements are in Group I of the Periodic Table and two are in Group VII.
physical state at
element reaction with water
room temperature
P reacts vigorously solid

Q does not react with water solid
R reacts explosively solid
S dissolves giving a coloured solution liquid
A P is below R in Group I.
B Q is above R in Group I.
C Q is below S in Group VII.
D R is below S in Group VII.

10
23 Which of the following could be a transition element?
melting point density in electrical

colour
in °C g / cm3 conductor
A 114 4.9 purple no

B 659 2.7 grey yes
C 1677 4.5 grey yes
D 3727 2.3 black yes
24 Two statements about argon are given.

1 Argon has a full outer shell of electrons.
2 Argon is very reactive and is used in lamps.
Which is correct?

25 A student investigated the reactions of four metals, R, S, T and U, with solutions of their salts.
The results are given in the table.
metal metal salt result
R S nitrate reacts
R T nitrate reacts
S U nitrate no reaction
T U nitrate reacts
U R nitrate no reaction
What is the order of reactivity of the metals, most reactive first?
A R→S→U→T
B R→T→U→S
C S → U → T→ R
D U→R→T→S
© UCLES 2016 0620/21/M/J/16

11
26 Three students, X, Y and Z, were told that solid P reacts with dilute acids and also conducts
electricity.
The table shows the students’ suggestions about the identity of P.
X Y Z
copper iron graphite
Which of the students are correct?
A X, Y and Z B X only C Y only D Z only
A Aluminium is used in the manufacture of aircraft because of its strength and high density.
B Copper is used in electrical wiring because of its strength and high density.
C Mild steel is used in the manufacture of car bodies because of its strength and resistance to
corrosion.
D Stainless steel is used in the construction of chemical plant because of its strength and
resistance to corrosion.
28 Aluminium is manufactured by electrolysis of aluminium oxide.
The diagram shows the electrolysis cell.
anode
cathode
+ +
aluminium oxide
in molten cryolite
molten aluminium
Which statement about the process is not correct?
A Aluminium ions gain electrons during the electrolysis and are reduced.
B Cryolite is added to reduce the melting point of the aluminium oxide.
C The anode and cathode are made of graphite.
D The cathode has to be replaced regularly because it is burnt away.

12
P Q
iron painted iron
air
water
tube P tube Q
A falls rises
B no change rises
C rises falls
D rises no change
atmosphere
planet
The table shows the composition of its atmosphere.
carbon dioxide 4
nitrogen 72
oxygen 24

D nitrogen only
© UCLES 2016 0620/21/M/J/16

13
31 Many car exhaust systems contain a catalytic converter.
Which change does not occur in a catalytic converter?
A carbon dioxide → carbon
B carbon monoxide → carbon dioxide
C nitrogen oxides → nitrogen
D unburnt hydrocarbons → carbon dioxide and water
32 Ammonia is formed by a reversible reaction.
N2(g) + 3H2(g) 2NH3(g)
Which changes in conditions would increase the yield of ammonia?
increase in increase in
pressure temperature
A
B
C
D
33 The equation for an exothermic reaction in the Contact process is shown.
2SO2(g) + O2(g) → 2SO3(g)
Which effects do increasing the temperature and using a catalyst have on the rate of formation of
sulfur trioxide, SO3?
increasing the using a

temperature catalyst
A rate decreases rate decreases

B rate decreases rate increases
C rate increases rate decreases
D rate increases rate increases

14
34 A farmer’s soil is very low in both nitrogen (N) and phosphorus (P).
Which fertiliser would improve the quality of this soil most effectively?
percentage
nitrogen (N) phosphorus (P) potassium (K)
A 11 11 27
B 12 37 10
C 28 10 10
D 31 29 9
35 The diagram shows the separation of petroleum into fractions.
gasoline
petroleum Z
bitumen
What could X, Y and Z represent?
X Y Z
A diesel oil lubricating fraction paraffin

B lubricating fraction diesel oil paraffin
C paraffin lubricating fraction diesel oil
D paraffin diesel oil lubricating fraction
© UCLES 2016 0620/21/M/J/16

15
36 Which of the compounds shown are in the same homologous series?
1 CH3OH
2 CH3CH2OH
3 CH3COOH
4 CH3CH2CH2OH
37 Which compounds contain the same number of carbon, hydrogen and oxygen atoms?
W X Y Z
ethyl methanoate methyl ethanoate methyl methanoate ethyl ethanoate
A W and X B W and Y C X and Z D Y and Z
38 What is an advantage of producing ethanol by fermentation of sugar compared to the catalytic

addition of steam to ethene?
A The alcohol produced is purer.

B The process is faster.
C The process uses high temperature.
D The process uses renewable raw materials.

16
39 The structure of a monomer is shown.
Cl F
H C C H
Which polymer can be made from this monomer?
A B
Cl Cl Cl Cl Cl F Cl F
C C C C C C C C
Cl Cl Cl Cl H H H H
C D
Cl F Cl F F F F F
C C C C C C C C
Cl F Cl F Cl Cl Cl Cl
40 Which formula represents a polyester?
A O O O O
H O H O
B N C N C N C
H O
O O O O
C C C O O C C O O
O O O O O
D C C N N C C N N C
H H H H
© UCLES 2016 0620/21/M/J/16

17
BLANK PAGE
© UCLES 2016 0620/21/M/J/16

18
BLANK PAGE
© UCLES 2016 0620/21/M/J/16

19
BLANK PAGE
© UCLES 2016 0620/21/M/J/16

Group
© UCLES 2016
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
20
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/21/M/J/16
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/21
MARK SCHEME
Maximum Mark: 40
Published
Teachers.

Question Question
Key Key
Number Number
1 C 21 A
2 C 22 C
3 D 23 C
4 B 24 C
5 C 25 B
6 C 26 C
7 A 27 D
8 D 28 D
9 C 29 D
10 A 30 A
11 D 31 A
12 C 32 B
13 C 33 D
14 D 34 D
15 A 35 D
16 B 36 B
17 C 37 A
18 D 38 D
19 D 39 B
20 A 40 C

CHEMISTRY 0620/31
*3293960889*
Paper 3 Theory (Core) May/June 2016

1 hour 15 minutes
Additional Materials: No Additional Materials are required.

06_0620_31_2016_1.11
2
1 The structures of some substances containing chlorine are shown.
A B C
Cl
Cl Cl Cl − K+ Cl − K+
C
Cl Cl K+ Cl − K+ Cl −
Cl
Cl − K+ Cl − K+
D E
Cl H F
Cl Cl Cl
Cl C C C F Al Al
H H F Cl Cl Cl
(a) Answer the following questions about these substances.
(i) Which substance is a diatomic molecule?
................................................................................................................................ [1]
(ii) Which substance represents part of an ionic structure?
................................................................................................................................ [1]
(iii) Which substance is an element?
................................................................................................................................
................................................................................................................................ [2]
(iv) Determine the simplest formula for substance D.
................................................................................................................................ [1]
© UCLES 2016 06_0620_31_2016_1.11

3
(b) The symbols for two isotopes of chlorine are shown.
Cl Cl
................................................................................................................................ [1]
(ii) Determine the number of neutrons present in one atom of the isotope Cl .
................................................................................................................................ [1]
(iii) Draw the electronic structure of a chlorine atom. Show all shells and all electrons.
[2]
[Total: 9]
© UCLES 2016 06_0620_31_2016_1.11 [Turn over

4
2 A bicycle maker wants to choose a suitable material to make bicycle frames.

The table shows the properties of some materials that could be used.
material relative density resistance to cost per tonne

3
strength in g / cm corrosion in $ / tonne
aluminium 8 2.7 very good 1500
iron 21 7.9 poor 450
stainless 24 7.9 very good 600

steel
titanium 27 4.5 very good 15000
zinc 14 7.1 good 1300
(a) Which material is the most suitable for making the bicycle frame?
Explain your answer using information from the table.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
........................................................................................................................................... [3]
(b) Aluminium is extracted from aluminium oxide by electrolysis.
(i) State the name of the main ore of aluminium.
................................................................................................................................ [1]
(ii) Suggest why aluminium is extracted by electrolysis and not by reduction with carbon.
................................................................................................................................ [1]
(iii) Molten aluminium oxide is electrolysed using graphite electrodes.
Predict the products of this electrolysis at
the positive electrode (anode), ..............................................................................
the negative electrode (cathode). ........................................................................ [2]
© UCLES 2016 06_0620_31_2016_1.11

5
(c) The diagram shows the changes of state when zinc vapour is cooled slowly to room temperature.
zinc condensation molten freezing solid

vapour zinc (solidification) zinc
Explain what happens during these changes in terms of
• the distance between the particles,

• the type of motion shown by the particles.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
........................................................................................................................................... [4]
[Total: 11]
© UCLES 2016 06_0620_31_2016_1.11 [Turn over

6
3 The table shows some properties of the Group I metals.
metal density melting point boiling point

3
in g / cm / ºC / ºC
lithium 0.53 181 1342
sodium 98 883
potassium 0.86 63 760
rubidium 1.53 39 686
caesium 29 669
(a) (i) Describe the trend in boiling points of the Group I metals.
................................................................................................................................ [1]
(ii) Predict the density of caesium.
................................................................................................................................ [1]
(iii) Deduce the state of caesium at 20 ºC.
................................................................................................................................
................................................................................................................................ [2]
(b) Complete the word equation for the reaction of rubidium with water.
rubidium + water → ............................................. + .............................................

[2]
© UCLES 2016 06_0620_31_2016_1.11

7
(c) The dye, indigotin, is formed when compound F is exposed to air.

The structure of compound F is shown below.
H C O– Na+
C C C
C C C
H C N H
H H
Complete the table and calculate the relative molecular mass of compound F.
type of atom number of atoms atomic mass
carbon 8 12 8 12 96
hydrogen
nitrogen 1 14 1 14 14
oxygen 1 16 1 16 16
sodium
relative molecular mass = .............................................. [2]
© UCLES 2016 06_0620_31_2016_1.11 [Turn over

8
(d) Three dye mixtures, J, K and L, were spotted onto a piece of chromatography paper. Three
pure dyes, X, Y and Z, were also spotted onto the same piece of paper.
The diagram shows the results of this chromatography.
J K L X Y Z
(i) Suggest why the base line was drawn in pencil and not in ink.
................................................................................................................................ [1]
(ii) Which dye mixture, J, K or L, contains a dye which did not move during this
chromatography?
................................................................................................................................ [1]
(iii) Which dye mixture, J, K or L, contains both dye X and dye Y?
................................................................................................................................ [1]
(iv) Which dye mixture, J, K or L, does not contain dye Z?
................................................................................................................................ [1]
[Total: 12]
© UCLES 2016 06_0620_31_2016_1.11

9
4 The structures of some organic compounds are shown.
P Q R
H H
H H H H H H H
H C
C C H H C C C H H C C C
C C H H H H H H
H C
H
H H
S T U
H H H H H H H H H
H C C C O H H C C H H C C C C O H
H H H H H H H H H
(a) (i) Which two of these compounds are alcohols?
................................................................................................................................
................................................................................................................................ [2]
(ii) Which two of these compounds are saturated hydrocarbons?
................................................................................................................................ [1]
(b) Methanol and ethanol are alcohols in the same homologous series.
Complete the following sentence about a homologous series using words from the list.
alcohols chemical compounds elements
functional mixtures physical
A homologous series is a family of similar .......................................... with similar
.......................................... properties due to the same .......................................... group.

[3]
© UCLES 2016 06_0620_31_2016_1.11 [Turn over

10
(c) Ethene is an alkene.
(i) Draw the structure of ethene showing all atoms and all bonds.
[1]
(ii) Describe how aqueous bromine is used to show that ethene is an unsaturated
compound.
................................................................................................................................
................................................................................................................................ [2]
(iii) Ethene is manufactured by cracking.
State the conditions needed for cracking.
................................................................................................................................ [1]
(iv) Complete the chemical equation for the cracking of hexadecane, C16H34 , to form propene
and one other hydrocarbon.
C16H34 → C3H6 + .........................

[1]
[Total: 11]
© UCLES 2016 06_0620_31_2016_1.11

11
5 The Group VII elements are called the halogens.
(a) Describe the trends in
• the physical properties of the halogens,
• the reactivity of halogens with other halide ions.
Include a relevant word equation in your answer.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
........................................................................................................................................... [5]
(b) Iodine reacts with hot concentrated nitric acid.
I2 10HNO3 2HIO3 4H2O 10NO2
(i) Explain why this reaction could have an adverse effect on health if not carried out in a
fume cupboard.
................................................................................................................................
................................................................................................................................ [2]
(ii) Nitric acid is strongly acidic.
Which one of the following pH values represents a strongly acidic solution?
A pH 1 B pH 7 C pH 9 D pH 13
[1]
© UCLES 2016 06_0620_31_2016_1.11 [Turn over

12
(iii) Nitric acid reacts with zinc oxide.
State the names of the products of this reaction.
............................................ and ............................................

[2]
[Total: 10]
6 Ammonia is manufactured by the reaction of nitrogen with hydrogen in the presence of a catalyst.
(a) What is the purpose of a catalyst?
........................................................................................................................................... [1]
(b) The reaction is reversible.
Complete the equation below by adding the sign for a reversible reaction.
N2 + 3H2 2NH3
[1]
(c) The energy level diagram for this reaction is shown.
Is this reaction exothermic or endothermic?
N2 + 3H2
energy
2NH3
...........................................................................................................................................
........................................................................................................................................... [1]
© UCLES 2016 06_0620_31_2016_1.11

13
(d) The graph shows how the percentage yield of ammonia changes with temperature when the
pressure is kept constant.
100
80
60
% yield
of ammonia
40
20
0
0 100 200 300 400 500 600 700
temperature / °C
(i) Describe how the percentage yield of ammonia changes with temperature.
................................................................................................................................ [1]
(ii) Determine the percentage yield of ammonia at 350 ºC.
................................................................................................................................ [1]
(e) Describe a test for ammonia.
test.....................................................................................................................................
result.................................................................................................................................. [2]
© UCLES 2016 06_0620_31_2016_1.11 [Turn over

14
(f) Ammonia is a weak base.
Describe how you would measure the pH of an aqueous solution of a weak base using Universal
Indicator.
...........................................................................................................................................
........................................................................................................................................... [2]
(g) Complete the chemical equation for the reaction of ammonia with chlorine.
........NH3 + 3Cl2 → N2 + ......HCl

[2]
[Total: 11]
7 Calcium carbonate reacts with dilute hydrochloric acid.
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(I)
A student investigated this reaction by measuring the volume of carbon dioxide released every
minute at constant temperature.
(a) Draw a diagram of the apparatus that the student could use to investigate this reaction.
[2]
© UCLES 2016 06_0620_31_2016_1.11

15
(b) The graph shows the results of this reaction using three samples of calcium carbonate of the
same mass: large pieces, medium-sized pieces and small pieces.
50
40
small
medium
30
volume of
carbon dioxide
/ cm3 large
20
10
0
0 50 100 150 200 250 300 350
time / s
(i) Which sample, large, medium or small pieces, gave the fastest initial rate of reaction?
Use the graph to explain your answer.
................................................................................................................................
................................................................................................................................ [2]
(ii) The experiment was repeated using powdered calcium carbonate of the same mass.
Draw a line on the grid above to show how the volume of carbon dioxide changes with
time for this experiment. [2]
(iii) At what time was the reaction just complete when small pieces of calcium carbonate
were used?
................................................................................................................................ [1]
© UCLES 2016 06_0620_31_2016_1.11 [Turn over

16
(c) When calcium carbonate is heated strongly, calcium oxide is formed.
(i) Give one use of calcium oxide.
................................................................................................................................ [1]
(ii) What type of oxide is calcium oxide?
................................................................................................................................
................................................................................................................................ [2]
[Total: 10]
8 A teacher passed hydrogen gas over hot copper(II) oxide.
CuO(s) + H2(g) → Cu(s) + H2O(g)
(a) Which substance is reduced in this reaction?
...........................................................................................................................................
........................................................................................................................................... [2]
© UCLES 2016 06_0620_31_2016_1.11

17
(b) The diagram shows the apparatus used.
dry
hydrogen gas
copper(II) oxide
ice bath
water
The hydrogen was passed over the hot copper(II) oxide until the reaction was complete.
(i) As the experiment proceeds, suggest what happens to the mass of copper(II) oxide.
................................................................................................................................ [1]
(ii) Suggest why electrical heating is used in this experiment and not a Bunsen burner.
................................................................................................................................ [1]
(iii) Describe the chemical test for the presence of water.
test..........................................................................................................................
result....................................................................................................................... [2]
[Total: 6]
© UCLES 2016 06_0620_31_2016_1.11 [Turn over

18
BLANK PAGE
© UCLES 2016 06_0620_31_2016_1.11

19
BLANK PAGE
© UCLES 2016 06_0620_31_2016_1.11

© UCLES 2016
Group

1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
20
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
06_0620_31_2016_1.11
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/31
MARK SCHEME
Maximum Mark: 80
Published
Teachers.


• R reject
• () the word / phrase in brackets is not required, but sets the context

1(a)(i) B / chlorine / Cl 2; 1
1(a)(ii) C / KCl / potassium chloride; 1
1(a)(iii) 2
B; 1
has only one type of atom; 1
1(a)(iv) C3H3F3Cl2 ; 1
1(b)(i) different number of neutrons / different mass numbers / different numbers of nucleons; 1
1(b)(ii) 18; 1
1(b)(iii) 2
7 electrons in the outer shell; 1
first shell has 2 electrons and second shell has 8 electrons; 1

2(a) 3
stainless steel;
any 2 from:
(very) strong;
(good) resistance to corrosion;
cheap;
OR
iron;
strong;
cheap;
OR
aluminium;
low density;
OR
titanium;
any 2 from:
strong;
low density;
OR
zinc;
2(b)(i) bauxite; 1
2(b)(ii) aluminium is too reactive / aluminium is high in the electrochemical series / aluminium is very reactive; 1

2(b)(iii) 2
anode: oxygen / O2; 1
cathode: aluminium / Al; 1
2(c) any 4 from: 4
• atoms in gas far apart / all over the place;

• atoms in gas moving (very) fast / move freely / bouncing around / move randomly;
• atoms slow down during condensation / move less than before;
• atoms get closer together in condensation;
• atoms in liquid are close together / touching;
• atoms in liquid slide over each other / atoms in liquids move slowly / restricted movement;
• atoms slow down (further) during freezing / atoms in liquid move more than in solid;
• atoms in solid only vibrate;
• atoms in solid are / touching / close to each other / closely packed / tightly packed;

3(a)(i) decreases down the Group I / increases up the Group I; 1

3
3(a)(ii) 1.88 (1.60–2.50) (g / cm ); 1
3(a)(iii) 2
solid; 1
20°C is below the melting point / the melting point is above 20°C; 1
3(b) 2
rubidium hydroxide; 1
hydrogen; 1
3(c) 155; 2
(1 mark for hydrogen = (6 × 1) = 6 / sodium = (1 × 23) = 23)
3(d)(i) pencil will not smear / pencil line will not move / ink will smear / ink will undergo chromatography / ink would spread / 1
ink would travel upwards / pencil mark would not spread;
3(d)(ii) K; 1
3(d)(iii) J; 1
3(d)(iv) J; 1

4(a)(i) 2
S and U; 1
both have OH (group); 1
4(a)(ii) Q and T; 1
4(b) 3
compounds; 1
chemical; 1
functional; 1
4(c)(i) 1
;
4(c)(ii) 2
aqueous bromine is added to (test tube of) ethene / aqueous bromine is orange; 1
aqueous bromine turns colourless / solution turns colourless; 1
4(c)(iii) high temperature / heat; 1
4(c)(iv) C13H28; 1

5(a) 5
any 3 physical properties: 3
• melting point increases down the Group;
• boiling point increases down the Group;
• density increases down the Group;
• colour gets darker down the Group / states goes from gas to liquid to solid down the Group;
reactivity: 2
• more reactive halogen displaces less reactive halogen (from halide);
• correct word equation, e.g. chlorine + potassium bromide → potassium chloride + bromine;
5(b)(i) 2
nitrogen dioxide (formed) / NO2 (formed) / nitrogen oxide (formed) / gas (formed); 1
damages lungs / irritates eyes / sore throat / skin burns / difficulty swallowing / persistent coughing / headache 1
/ vomiting;
5(b)(ii) pH 1; 1
5(b)(iii) 2
zinc nitrate; 1
water; 1

6(a) increases rate of reaction / speeds up reaction; 1

6(b) ⇌; 1
6(c) exothermic and products have less energy than reactants; 1

6(d)(i) (yield) decreases with increasing temperature ora / the lower the temperature, the higher the yield ora; 1
6(d)(ii) 42%; 1
6(e) 2
(damp) red litmus paper turns blue 2
(1 mark for red litmus paper)
OR
concentrated HCl (on glass rod) gives white fumes 2
(1 mark for concentrated HCl (on glass rod))
6(f) 2
add Universal Indicator to the solution / observe colour; 1
compare with colour chart; 1
6(g) 2
2 (NH3); 1
6 (HCl ); 1

7(a) 2
(gas) syringe leading to flask / beaker / test tube OR flask and tube leading to upturned measuring cylinder over 1
trough of water;
closed apparatus with no air gaps; 1
7(b)(i) 2
small pieces; 1
line / curve / graph steepest; 1
7(b)(ii) 2
line to the left of the small pieces starting at (0, 0); 1
finishing at 45 cm3 and before the other lines; 1
7(b)(iii) any value between 205 s and 215 s (inclusive); 1
7(c)(i) neutralising (acidic) soils / neutralising (acidic) waste / steelmaking / self-heating cans / making concrete / 1
making glass / water treatment / making plaster / making paper / flue-gas desulfurisation / neutralising acids / making
limewater;
7(c)(ii) 2
basic oxide; 1
because it is a metal oxide / because it would react with acid / neutralizes acids / calcium is on the left of the Periodic 1
Table;

8(a) 2
copper(II) oxide; 1
loses oxygen; 1
8(b)(i) (mass of copper oxide in tube) decreases; 1
8(b)(ii) hydrogen is flammable / hydrogen is explosive; 1
8(b)(iii) 2
anhydrous copper(II) sulfate goes blue / white copper(II) sulfate goes blue 2
(1 mark for anhydrous copper (II) sulfate / white copper(II) sulfate)
OR
anhydrous cobalt(II) chloride goes pink / blue cobalt(II) chloride goes pink 2
(1 mark for anhydrous cobalt(II) chloride / blue cobalt(II) chloride)

*4054381962*
CHEMISTRY 0620/41

Paper 4 Theory (Extended) May/June 2016

1 hour 15 minutes

IB16 06_0620_41/4RP
2
1 Protons, neutrons and electrons are subatomic particles.
(a) Complete the table to show the relative mass and relative charge of a proton, a neutron and an
electron.
particle relative mass relative charge
proton
neutron
1
electron
1840
[3]
(b) Bromine has two isotopes.
(i) Define the term isotope.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) Explain why the two isotopes of bromine have the same chemical properties.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(c) The table shows the number of protons, neutrons and electrons in some atoms and ions.
Complete the table.

particle
protons neutrons electrons
7
3 Li
34 2-
16 S
19 22 18
[5]
[Total: 12]
© UCLES 2016 0620/41/M/J/16

3
2 Period 3 contains the elements sodium to argon. This question asks about the chemistry of each of
the Period 3 elements or their compounds.
(a) Sodium nitrate is a white crystalline solid. When heated it melts and the following reaction
occurs.
2NaNO3(l) → 2NaNO2(l) + O2(g)
A 3.40 g sample of sodium nitrate is heated.
Calculate the
• number of moles of NaNO3 used,
.................................. mol
• number of moles of O2 formed,
.................................. mol
• volume of O2 formed, in dm3 (measured at r.t.p.).
.................................. dm3
[3]
(b) Magnesium reacts slowly with warm water to form a base, magnesium hydroxide.
(i) Explain what is meant by the term base.
. ...................................................................................................................................... [1]
(ii) Write a chemical equation for the reaction between magnesium and warm water.
. ...................................................................................................................................... [2]

4
(c) Aluminium oxide is amphoteric. It is insoluble in water.
Describe experiments to show that aluminium oxide is amphoteric.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(d) Silicon(IV) oxide has a giant structure.
(i) Name the type of bonding in silicon(IV) oxide.
. ...................................................................................................................................... [1]
(ii) Give two physical properties of silicon(IV) oxide.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(e) Calcium phosphate is used in fertilisers. The bonding in calcium phosphate is ionic.
Calcium phosphate contains the phosphate ion, PO43–.
(i) What is ionic bonding?
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) Deduce the formula of calcium phosphate.
. ...................................................................................................................................... [1]
© UCLES 2016 0620/41/M/J/16

5
(f) Sulfur tetrafluoride, SF4, can be made by combining gaseous sulfur with fluorine.
S(g) + 2F2(g) → SF4(g)
The reaction is exothermic.
(i) Complete the energy level diagram for this reaction. Include an arrow which clearly shows
the energy change during the reaction.
S(g) + 2F2(g)
energy
[3]
(ii) During the reaction the amount of energy given out is 780 kJ / mol.
The F–F bond energy is 160 kJ / mol.
Use this information to determine the bond energy, in kJ / mol, of one S–F bond in SF4.
S + F F → F S F
F F
F
.................................. kJ / mol [3]

6
(g) Chlorine and compounds of chlorine are important in water treatment and in laboratory testing
for water.
(i) Chlorine is added to water to make the water safe to drink.
Explain why adding chlorine makes water safe to drink.
. ...................................................................................................................................... [1]
(ii) A compound of chlorine is used in the laboratory to test for the presence of water.
Name the compound of chlorine used in this test and describe the colour change seen in
a positive result of this test.
name of compound . ............................................................................................................
colour change from ................................................... to . ..................................................

[3]
(h) Argon is an unreactive noble gas.
(i) Explain why argon is unreactive.
. ...................................................................................................................................... [1]
(ii) Give one use of argon.
. ...................................................................................................................................... [1]
[Total: 27]
© UCLES 2016 0620/41/M/J/16

7

8
3 When aqueous sodium thiosulfate and dilute hydrochloric acid are mixed, a precipitate of insoluble
sulfur is produced. This makes the mixture difficult to see through.
Na2S2O3(aq) + 2HCl (aq) → S(s) + 2NaCl (aq) + H2O(l) + SO2(g)
The time taken for the cross to disappear from view is measured.
A student adds the following volumes of aqueous sodium thiosulfate, dilute hydrochloric acid and
distilled water to the conical flask.
The time taken for the formation of the precipitate of sulfur to make the cross disappear from view
is recorded.
experiment volume of volume of volume of time taken for

number sodium thiosulfate hydrochloric acid distilled water cross to disappear
/ cm3 / cm3 / cm3 from view / s
1 10 10 40 56
2 20 10 30 28
(a) State the order in which the aqueous sodium thiosulfate, hydrochloric acid and distilled water
should be added to the flask.
....................................................................................................................................................
.............................................................................................................................................. [1]
© UCLES 2016 0620/41/M/J/16

9
(b) In experiment 3 the student wanted the sodium thiosulfate to be double the concentration used
in experiment 2.
(i) Complete the table to show the volumes which should be used and the expected time
taken for the cross to disappear from view in experiment 3. [2]
(ii) Use collision theory to explain why increasing the concentration of sodium thiosulfate
would change the rate of reaction.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(c) The student repeated experiment 1 at a higher temperature.
Use collision theory to explain why the rate of reaction would increase.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 8]

10
4 Electroplating steel objects with silver involves a three-step process.
step 1 A coating of copper is applied to the object.
step 2 A coating of nickel is applied to the object.
step 3 The coating of silver is applied to the object.
(a) A diagram of the apparatus used for step 1 is shown.
+ –
copper (anode)
steel object (cathode)

electrolyte
(i) The chemical process taking place on the surface of the object is
Cu2+(aq) + 2e– → Cu(s)
Explain whether this process is oxidation or reduction.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(ii) Explain why the concentration of copper ions in the electrolyte remains constant throughout
step 1.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
© UCLES 2016 0620/41/M/J/16

11
(b) Give two changes which would be needed in order to coat nickel onto the object in step 2.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(c) Copper, nickel and silver are transition elements.

Typical physical properties of transition elements are a high density and a high melting point.
Give three different properties of transition metals which are not typical of other metals.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 8]

12
5 Sulfuric acid is produced by the Contact process. The steps of the Contact process are shown.
starting step 1 sulfur step 2 sulfur step 3 oleum

step 4 sulfuric
material dioxide trioxide acid
(a) Sulfur is a common starting material for the Contact process.
Name a source of sulfur.
.............................................................................................................................................. [1]
(b) Describe step 2, giving reaction conditions and a chemical equation. Reference to reaction
rate and yield is not required.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]
(c) Step 3 involves adding sulfur trioxide to concentrated sulfuric acid to form oleum.
H2SO4 + SO3 → ................................

[1]
© UCLES 2016 0620/41/M/J/16

13
(d) Dilute sulfuric acid is a typical acid.
A student adds excess dilute sulfuric acid to a sample of solid copper(II) carbonate in a
test-tube.
(i) Give three observations the student would make.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) Give the names of all products formed.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(e) Concentrated sulfuric acid has different properties to dilute sulfuric acid.
When concentrated sulfuric acid is added to glucose, C6H12O6, steam is given off and a black
solid is formed.
(i) Name the black solid.
. ...................................................................................................................................... [1]
(ii) What type of reaction has occurred?
. ...................................................................................................................................... [1]
[Total: 12]

14
6 Petroleum is a source of many important chemicals.
(a) Name two industrial processes which must take place to produce alkenes from petroleum.
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) Ethene, CH2=CH2, and propene, CH2=CHCH3, can both be converted into polymers.
(i) What type of polymerisation takes place when ethene forms a polymer?
. ...................................................................................................................................... [1]
(ii) What is the empirical formula of the polymer formed from ethene?
. ...................................................................................................................................... [1]
(iii) Propene has the structural formula CH2=CHCH3.
Draw two repeat units of the polymer made from propene.
[2]
(c) Ethene will react with steam to form ethanol.
Propene will react with steam to form two isomers, both of which are alcohols.
Suggest the structures of these alcohols.
[2]
© UCLES 2016 0620/41/M/J/16

15
(d) Esters are organic chemicals noted for their characteristic smells. Ethanoic acid and methanol
will react to form an ester.
(i) Name the catalyst needed to form an ester from ethanoic acid and methanol.
. ...................................................................................................................................... [1]
(ii) Name the ester formed when ethanoic acid reacts with methanol.
. ...................................................................................................................................... [1]
(iii) Draw the structure of the ester formed when ethanoic acid reacts with methanol. Show all
bonds.
[2]
(iv) Give the name of a polyester.
. ...................................................................................................................................... [1]
[Total: 13]
© UCLES 2016 0620/41/M/J/16

Group
© UCLES 2016
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/41/M/J/16
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/41
MARK SCHEME
Maximum Mark: 80
Published
Teachers.


• R reject

1(a) 3
particle relative mass relative charge
proton 1 +1
neutron 1 nil
electron 1 / 1840 –1
1(b)(i) 2
M1 atom(s) of the same element; 1
M2 with different number of neutrons; 1
1(b)(ii) 2
M1 (both have) the same number of electrons; 1
M2 in the outer shell; 1
1(c) 5
particle
7
3Li 3 4 3
34 2–
16S 16 18 18
41 +
19K 19 22 18

2(a) 3
number of moles of NaNO3 used: 3.40 / 85 = 0.04(00) (mol)
OR
4.(00) × 10–2 (mol);
number of moles of O2 formed: 0.04 / 2 = 0.02(00) (mol)

OR
2.(00) × 10–2 (mol);
volume of O2 formed: 0.02 × 24 = 0.48 (dm3);

2(b)(i) (a substance which is) a proton / H+ / hydrogen ion acceptor; 1
2(b)(ii) Mg(s) + 2H2O(l) → Mg(OH)2(aq) + H2(g) 2
Mg(OH)2; rest of equation;
2(c) 3
M1 add a named acid, e.g. HCl and a named alkali, e.g. NaOH; 1
M2 Al 2O3 will react with / neutralises both reagents; 1
M3 and so it will dissolve into the reagent / form a solution; 1
2(d)(i) covalent; 1
2(d)(ii) any 2 from: 2
high melting point / high boiling point;
poor conductor (of electricity);
hard;
insoluble;
2(e)(i) 2
M1 (electrostatic) attraction; 1
M2 between oppositely charged ions; 1
2(e)(ii) Ca3(PO4)2; 1

2(f)(i) 3
1
M1 exothermic mark: horizontal product energy line at lower energy than that of reactant energy line; 1
M2 label of product mark: SF4; 1
M3 correct direction of vertical heat of reaction arrow: arrow must start level with reactant energy and finish level
with product energy and must have only one (correct) arrow-head;
2(f)(ii) 3
M1 bond energy of 2F2: 2 × F–F = 2 × 160 = 320 (kJ / mol); 1
M2 bond energy of all bonds in SF4: 780 + 320 = 1100 (kJ / mol); 1
M3 calculated bond energy of SF4 divided by 4: 1100 / 4 = 275 (kJ / mol); 1
2(g)(i) kills bacteria; 1
2(g)(ii) 3
name of compound: cobalt(II) chloride; 1
from: blue; 1
to: pink; 1
2(h)(i) it has a complete outer shell / a full outer shell / 8 electrons in the outer shell; 1
2(h)(ii) (in) lamps; 1

3(a) 1 Na2S2O3 2 H2O 3 HCl OR 1

1 HCl 2 H2O 3 Na2S2O3 OR
1 H2O 2 Na2S2O3 3 HCl OR
1 H2O 2 HCl 3 Na2S2O3 ;
3(b)(i) 2
M1 volumes 40 : 10 : 10; 1
M2 time = 14; 1
3(b)(ii) 2
M1 more particles per unit volume / particles are closer together; 1
M2 increases the rate of collisions / there are more collisions per unit time; 1
3(c) 3
M1 particles gain more energy and move faster; 1
M2 increasing rate of collisions / more collisions per unit time; 1
M3 higher proportion of particles have sufficient energy to react / collisions have sufficient energy to react / are 1
above the activation energy;

4(a)(i) reduction and (the Cu2+ ion / copper ions) is gaining electrons / is decreasing in oxidation number; 1
4(a)(ii) 2
formation of Cu2+ / copper ions at the anode happens at the same rate as; 1
removal of Cu2+ / copper ions at the cathode ora; 1
4(b) 2
replace (anode of) copper with nickel; 1
replace electrolyte with nickel(II) sulfate / NiSO4; 1
4(c) 3
(good) catalysts; 1
variable oxidation numbers; 1
form coloured compounds / coloured ions; 1

5(a) (sulfur-containing) fossil fuels; 1

5(b) 5
M1 vanadium pentoxide / vanadium(V) oxide / V2O5 (catalyst); 1
M2 1–5 atmospheres (units required); 1
M3 450 °C (units required); 1
M4 2SO2 + O2 → 2SO3; 1
M5 equilibrium / reversible reaction; 1
5(c) H2S2O7; 1
5(d)(i) 3 correct (2 marks) 2
2 correct (1 mark)
bubbles / effervescence / fizzing;

dissolves / disappears / forms a solution;
blue (solution);
5(d)(ii) carbon dioxide and water and copper(II) sulfate; 1
5(e)(i) carbon; 1
5(e)(ii) dehydration; 1

6(a) 2
fractional distillation; 1
cracking; 1
6(b)(i) addition; 1
6(b)(ii) CH2; 1
6(b)(iii) 2
M1 chain of 4 carbon atoms with single bonds and continuation bonds;

M2 correctly positioned CH3 side chains;
6(c) 2
; ;
6(d)(i) (concentrated) sulfuric acid; 1

6(d)(ii) methyl ethanoate; 1
6(d)(iii) 2
M1 ester link;
M2 rest of molecule;
6(d)(iv) terylene; 1

CHEMISTRY 0620/51

*9033818783*
caution. Safety glasses should be provided.
where relevant.
C = corrosive MH = moderate hazard
HH = health hazard T = acutely toxic
F = flammable O = oxidising
N = hazardous to the aquatic environment
by phone: +44 1223 553554,
by fax: +44 1223 553558,
IB16 06_0620_51CI/3RP
2
For Question 1
(d) 100 cm3 of an aqueous solution of sodium carbonate, Na2CO3, of concentration

0.05 mol / dm3, labelled aqueous sodium carbonate
(This can be made by adding 5.3 g of anhydrous sodium carbonate to 500 cm3 of
distilled water. Dissolve the solid and then make the volume up to 1 dm3 with distilled
water.)
(e) 100 cm3 of hydrochloric acid of concentration 0.10 mol / dm3, labelled solution A
(f) 100 cm3 of hydrochloric acid of concentration 0.20 mol / dm3, labelled solution B
[F][MH][HH] (h) thymolphthalein indicator
[F][MH][HH] (i) methyl orange indicator
(j) a white tile
(k) funnel for filling burette
(l) teat pipette
© UCLES 2016 0620/51/CI/M/J/16

3
For Question 2
(a) 0.5 g of sodium bromide, NaBr, labelled solid C
(b) 15 cm3 of an aqueous solution of chromium(III) chloride, CrCl 3.6H2O, of concentration

0.1 mol / dm3, labelled solution D
(c) distilled water
(d) apparatus for a flame test

One method is to dip a wooden splint into dilute hydrochloric acid and then into the solid,
followed by insertion into a blue flame.
(e) rack of six test-tubes and stopper to fit
[N][MH] (f) aqueous silver nitrate of sufficient concentration to give a positive halide test
[C] (g) aqueous nitric acid of concentration 1 mol / dm3
[C] (h) aqueous sodium hydroxide of concentration 1 mol / dm3
[N][MH] (i) aqueous ammonia of concentration 1 mol / dm3
(j) spatula
(k) teat pipettes
(l) pH indicator paper and chart
Note: Labels do not need to include concentrations.

4
© UCLES 2016 0620/51/CI/M/J/16

5

6
© UCLES 2016 0620/51/CI/M/J/16

7
penalised.
© UCLES 2016 0620/51/CI/M/J/16

[Turn over
8
CIE on the normal Application for Special Consideration form.
NAME OF CENTRE ...............................................................................................................................
CENTRE NUMBER ...................................................
SIGNED .......................................................
Supervisor
of the examination.
NAME .....................................................................................................................................................
(in block capitals)
© UCLES 2016 0620/51/CI/M/J/16

*8113146472*
CHEMISTRY 0620/51


1 hour 15 minutes

Practical notes are provided on pages 7 and 8.
Total
IB16 06_0620_51/7RP
2
1 You are going to investigate the reaction between aqueous sodium carbonate and two different
solutions of dilute hydrochloric acid labelled A and B.
Instructions
(a) Experiment 1
Use a measuring cylinder to pour 25 cm3 of aqueous sodium carbonate into a conical flask.
Add ten drops of thymolphthalein indicator to the conical flask.
Fill the burette provided up to the 0.0 cm3 mark with solution A of dilute hydrochloric acid.
Add solution A from the burette while swirling the flask, until the solution just changes colour.
Record the burette readings in the table below.
Experiment 2
Empty the conical flask and rinse it with distilled water.

Repeat Experiment 1 using methyl orange indicator instead of thymolphthalein.
Record the burette readings in the table below and complete the table.
Experiment 1 Experiment 2
difference / cm3
[4]
(b) Experiment 3
Empty the conical flask and rinse it with distilled water.

Pour away the contents of the burette and rinse the burette with solution B of dilute
hydrochloric acid.
Repeat Experiment 1 using solution B instead of solution A.
Record the burette readings in the table below and complete the table.
Experiment 3
difference / cm3
[2]
(c) What colour change was observed in the flask in Experiment 1?
from .............................................................. to ................................................................... [1]
© UCLES 2016 0620/51/M/J/16

3
(d) State one observation, other than colour change, when hydrochloric acid was added to sodium
carbonate.
.............................................................................................................................................. [1]
(e) Complete the sentence below.
Experiment ........... needed the largest volume of hydrochloric acid to change the colour of the
indicator. [1]
(f) What would be a more accurate method of measuring the volume of the aqueous
sodium carbonate?
.............................................................................................................................................. [1]
(g) What would be the effect on the results, if any, if the solutions of sodium carbonate were
warmed before adding the hydrochloric acid? Give a reason for your answer.
effect on results ..........................................................................................................................
reason ........................................................................................................................................
[2]
(h) (i) Determine the ratio of volumes of dilute hydrochloric acid used in Experiments 1 and 3.
. ...................................................................................................................................... [1]
(ii) Use your answer to (h)(i) to deduce how the concentration of solution A differs from that
of solution B.
. ...................................................................................................................................... [1]
(i) Suggest a different method, using standard laboratory chemicals, to determine which of the
solutions of dilute hydrochloric acid, A or B, is more concentrated.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(j) Hydrochloric acid is hazardous.
Suggest one safety precaution to follow when using hydrochloric acid.
.............................................................................................................................................. [1]
[Total: 18]

4
2 You are provided with two substances. Solid C is a salt and solution D is an aqueous solution of a
different salt.
Carry out the following tests on each substance, recording all of your observations at each stage.
tests on solid C
Add about half of solid C to about 10 cm3 of distilled water in a test-tube and shake to dissolve.
Divide the solution into two equal portions in two test-tubes, and carry out the following tests.
(a) (i) Test the pH of the first portion of the solution.
pH .................................................................................................................................. [1]
(ii) To the second portion of the solution, add about 1 cm3 of dilute nitric acid followed by
. ...................................................................................................................................... [2]
(b) Carry out a flame test on the rest of solid C.

.............................................................................................................................................. [1]
(c) Identify solid C.
.............................................................................................................................................. [2]
tests on solution D
Divide the solution D into three equal portions in three test-tubes and carry out the following tests.
(d) (i) Describe the appearance of the solution.
. ...................................................................................................................................... [1]
(ii) To the first portion of the solution, add drops of aqueous sodium hydroxide until a change
is seen.
Now add an excess of aqueous sodium hydroxide to the mixture.
. ............................................................................................................................................
. ...................................................................................................................................... [3]
© UCLES 2016 0620/51/M/J/16

5
(iii) To the second portion of the solution, add drops of aqueous ammonia until a change is
seen.
Now add an excess of aqueous ammonia to the mixture.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(iv) To the third portion of the solution, add about 1 cm3 of dilute nitric acid followed by aqueous
silver nitrate.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(e) What conclusions can you draw about solution D?
....................................................................................................................................................
.............................................................................................................................................. [2]
[Total: 16]

6
3 Calcium burns in air to form calcium oxide. The reaction is vigorous and some of the calcium oxide
can be lost as smoke.
Plan an investigation to determine the maximum mass of oxygen that combines to form calcium
oxide when 2 g of calcium granules are burnt in air.
You are provided with common laboratory apparatus and calcium granules.
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
..................................................................................................................................................... [6]
[Total: 6]
© UCLES 2016 0620/51/M/J/16

7

Test for anions

produced


colourless
colourless solution
© UCLES 2016 0620/51/M/J/16

8
sulfur dioxide (SO2) turns acidifed aqueous potassium

colourless
© UCLES 2016 0620/51/M/J/16

CHEMISTRY 0620/51
MARK SCHEME
Maximum Mark: 40
Published
Teachers.


• R reject


1(a) 4
M1 initial and final readings completed correctly; 1
M2 all readings to 1 decimal place; 1
M3 differences completed correctly; 1
M4 both results comparable to supervisor’s; 1
1(b) 2
initial, final readings and difference completed correctly; 1
both results comparable to supervisor’s; 1
1(c) blue to colourless; 1
1(d) bubbles / fizzing / effervescence; 1
1(e) Experiment 2; 1
1(f) use a pipette / burette; 1
1(g) 2
M1 effect on results: none; 1
M2 reason: no change in concentration; 1
1(h)(i) 2:1; 1
1(h)(ii) acid B is double the concentration of acid A ora / acid B is more concentrated ora; 1
1(i) 2
M1 appropriate named method that would work; 1
M2 reagents; 1
M3 result; 1
1(j) named protective clothing, e.g. goggles / gloves / lab coat; 1


2(a)(i) pH 7; 1
2(a)(ii) 2
cream; 1
precipitate; 1
2(b) yellow; 1
2(c) 2
sodium; 1
bromide; 1
2(d)(i) green; 1
2(d)(ii) 2
green; 1
precipitate; 1
with excess, (green) solution clears / precipitate dissolves; 1
2(d)(iii) 2
grey-green precipitate; 1
insoluble; 1
2(d)(iv) 2
white; 1
precipitate; 1
2(e) 2
chromium; 1
chloride; 1


3 any 6 from: 6
• weigh calcium;
• heat / burn;
• with lid / cover;
• allow air to enter / lift lid;
• cool;
• reweigh calcium oxide;
• reheat to constant mass;
• calculate / find the difference;

*3845366912*
CHEMISTRY 0620/61


1 hour

IB16 06_0620_61/3RP
2
1 The diagram shows the apparatus used to separate a mixture of water, boiling point 100 °C, and
ethanol, boiling point 78 °C.
condenser
water and
ethanol mixture
heat heat
(b) Label the arrows on the condenser. [1]
(c) Identify one mistake in the apparatus.
.............................................................................................................................................. [1]
(d) Which liquid would collect first? Explain your answer.
....................................................................................................................................................
.............................................................................................................................................. [2]
(e) Why would it be better to use an electrical heater instead of a Bunsen burner to heat the water
and ethanol mixture?
.............................................................................................................................................. [1]
[Total: 7]
© UCLES 2016 0620/61/M/J/16

3
2 A student investigated the reaction between aqueous sodium carbonate and two different solutions
of dilute hydrochloric acid, A and B.
The reaction is:
Na2CO3(aq) + 2HCl (aq) → 2NaCl (aq) + H2O(l) + CO2(g)
(a) Experiment 1
Using a measuring cylinder, 25 cm3 of aqueous sodium carbonate were poured into a conical
flask.
Thymolphthalein indicator was added to the conical flask.
A burette was filled up to the 0.0 cm3 mark with solution A of dilute hydrochloric acid. A was
added to the flask, until the solution just changed colour.
Use the burette diagram to record the reading in the table.
12
13
14
final reading
Experiment 2
Experiment 1 was repeated using methyl orange indicator instead of thymolphthalein.

Methyl orange is red-orange in acidic solutions and yellow in alkaline solutions.
Use the burette diagrams to record the readings in the table and complete the table.
12 38
13 39
14 40
experiment 1 experiment 2
difference / cm3
[4]

4
(b) What colour change was observed in the flask in experiment 2?
from ................................................................ to ................................................................. [1]
(c) Experiment 3
Experiment 1 was repeated using solution B of acid instead of solution A.
Use the burette diagrams to record the readings in the table and complete the table.
8 15
9 16
10 17
experiment 3
difference / cm3
[2]
(d) Suggest one observation, other than colour change, that is made when hydrochloric acid is
added to sodium carbonate.
.............................................................................................................................................. [1]
(e) Complete the sentence below.
Experiment .......... needed the largest volume of hydrochloric acid to change the colour of the
indicator. [1]
(f) What would be a more accurate method of measuring the volume of the aqueous
sodium carbonate?
.............................................................................................................................................. [1]
© UCLES 2016 0620/61/M/J/16

5
(g) What would be the effect on the results, if any, if the solutions of sodium carbonate were
warmed before adding the hydrochloric acid? Give a reason for your answer.
effect on results ..........................................................................................................................
reason ........................................................................................................................................
[2]
(h) (i) Determine the ratio of volumes of dilute hydrochloric acid used in experiments 1 and 3.
. ...................................................................................................................................... [1]
(ii) Use your answer to (h)(i) to deduce how the concentration of solution A differs from that
of solution B.
. ...................................................................................................................................... [1]
(i) Suggest a different method, using standard laboratory chemicals, to determine which of the
solutions of dilute hydrochloric acid, A or B, is more concentrated.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 17]

6
3 Two substances, C and D, were analysed. Solid C was a salt and solution D was an aqueous
solution of chromium(III) chloride.
The tests on solid C, and some of the observations, are in the following table.
tests observations
tests on solid C
Solid C was added to distilled water in a

test-tube and shaken to dissolve.
The solution was divided into two portions in

test-tubes, and the following tests carried out.
Appearance of the solution. colourless liquid
he pH of the first portion of the solution was

T pH = 7
tested.
ilute nitric acid was added to the second

D
portion of the solution followed by aqueous cream precipitate
silver nitrate.
A flame test was carried out on solid C. yellow flame colour
(a) Identify solid C.
.............................................................................................................................................. [2]
(b) Describe the appearance of solution D.
.............................................................................................................................................. [1]
(c) Tests were carried out on solution D.
Complete the observations for tests 1, 2 and 3.
(i) test 1
Drops of aqueous sodium hydroxide were added to solution D.
Excess aqueous sodium hydroxide was then added to the mixture.
observations ........................................................................................................................
. ...................................................................................................................................... [3]
© UCLES 2016 0620/61/M/J/16

7
(ii) test 2
Excess aqueous ammonia was added to solution D.
observations .................................................................................................................. [2]
(iii) test 3
Dilute nitric acid was added to solution D followed by aqueous silver nitrate.
observations .................................................................................................................. [1]
(d) Chromium(III) can be converted to chromium(VI). Chromium(VI) is hazardous.
Suggest one safety precaution when using chromium(VI).
.............................................................................................................................................. [1]
[Total: 10]

8
4 Calcium burns in air to form calcium oxide. The reaction is vigorous and some of the calcium oxide
can be lost as smoke.
Plan an investigation to determine the maximum mass of oxygen that combines to form calcium
oxide when 2 g of calcium granules are burnt in air.
You are provided with common laboratory apparatus and calcium granules.
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
...........................................................................................................................................................
..................................................................................................................................................... [6]
[Total: 6]
© UCLES 2016 0620/61/M/J/16

CHEMISTRY 0620/61
MARK SCHEME
Maximum Mark: 40
Published
Teachers.


• R reject

1(a) 2
fractionating column; 1
tripod; 1
1(b) water labelled twice; 1
1(c) heat under (the collecting) beaker; 1
1(d) 2
M1 ethanol; 1
M2 lowest / lower boiling point; 1
1(e) ethanol is flammable; 1

2(a) 4
final readings completed correctly: 13.2, 39.2; 1
initial readings completed correctly: 0.0, 12.8; 1
differences completed correctly: 13.2, 26.4; 1
all readings and differences to 1 decimal place; 1
2(b) yellow to orange / red / pink; 1
2(c) 2
initial and final readings completed correctly: 9.9, 16.5; 1
difference completed correctly: 6.6; 1
2(d) bubbles / fizzing / effervescence; 1
2(e) Experiment 2; 1
2(f) use a pipette / burette; 1
2(g) 2
effect on results: none owtte; 1
reason: no change in concentration owtte; 1
2(h)(i) 2:1; 1
2(h)(ii) acid B is double the concentration of acid A ora / acid B is more concentrated ora; 1
2(i) any suitable correct and different method 3
M1 method; 1
M2 reagents; 1
M3 result; 1

3(a) 2
sodium; 1
bromide; 1
3(b) green; 1
3(c)(i) 3
green; 1
precipitate; 1
with excess, green solution / clear / dissolves; 1
3(c)(ii) 2
grey-green; 1
precipitate; 1
3(c)(iii) white precipitate; 1
3(d) fume cupboard / protective clothing, e.g. gloves or goggles; 1
4 any 6 from: 6
weigh calcium;
with lid / cover;
heat / burn;
allow air to enter / lift lid;
cool;
reweigh CaO;
reheat to constant mass;
calculate / find the difference;

CHEMISTRY 0620/11
45 minutes
Soft clean eraser
*2950887077*

IB17 06_0620_11/FP
2
1 The diagram shows some changes of state.
P Q
solid liquid gas
R S
Which words describe the changes of state, P, Q, R and S?
P Q R S
A freezing boiling melting evaporation

B melting evaporation freezing condensation
C melting sublimation freezing evaporation
D sublimation evaporation melting condensation
2 The diagram shows part of a thermometer.
31
30
What is the reading on the thermometer?
A 30.2 B 30.3 C 31.7 D 31.8
3 Pure water has a boiling point of 100 °C and a freezing point of 0 °C.
What is the boiling point and freezing point of a sample of aqueous sodium chloride?
boiling point / °C freezing point / °C
A 98 –2
B 98 2
C 102 –2
D 102 2
© UCLES 2017 0620/11/M/J/17

3
4 Pure copper(II) sulfate crystals can be made by adding copper(II) oxide to hot dilute sulfuric acid.
The copper(II) oxide is added until it ......1...... .
The solution is ......2...... and then ......3...... to obtain the pure crystals.
Which words complete gaps 1, 2 and 3?
1 2 3
A is in excess cooled filtered

B is in excess filtered cooled
C changes colour cooled filtered
D changes colour filtered cooled
5 Which part of an atom has a relative mass of 1 and a relative charge of 0?
A electron
B neutron
C nucleus
D proton
6 Which molecule contains exactly two single covalent bonds?
A Cl 2 B CH4 C H2O D HCl
7 Sodium reacts with chlorine to form sodium chloride.
Which statements describe what happens to the sodium atoms in this reaction?
1 Sodium atoms form positive ions.

2 Sodium atoms form negative ions.
3 Sodium atoms gain electrons.
4 Sodium atoms lose electrons.

4
8 Diamond is extremely hard and does not conduct electricity.
Which statement explains these properties?
A It has a lattice of positive carbon ions in a ‘sea of electrons’.

B It has delocalised electrons and each carbon atom forms three covalent bonds with other
carbon atoms.
C It has no delocalised electrons and each carbon atom forms four covalent bonds with other
carbon atoms.
D It has strong ionic bonds between each carbon atom.
9 What is the relative formula mass of ammonium nitrate, NH4NO3?
A 80 B 108 C 122 D 150
10 Concentrated aqueous sodium chloride is electrolysed.
What is the main product formed at the positive electrode (anode)?
A chlorine
B hydrogen
C oxygen
D sodium
11 Some properties of four fuels are shown in the table.
Which fuel is a gas at room temperature and makes two products when it burns in a plentiful
supply of air?
melting point boiling point

fuel formula
/ °C / °C
A hydrogen H2 –259 –253

B methane CH4 –182 –164
C octane C8H18 –57 126
D wax C31H64 60 400
© UCLES 2017 0620/11/M/J/17

5

13 When sulfur is heated it undergoes a ......1...... change as it melts.
Further heating causes the sulfur to undergo a ......2...... change and form sulfur dioxide.
Which words complete gaps 1 and 2?
1 2
A chemical chemical
B chemical physical
C physical chemical
D physical physical
14 Which row correctly matches the experiment and observations to the identity of the underlined
substance?
experiment and observations identity of the underlined substance

A Blue crystals are heated. The crystals hydrated cobalt(II) chloride
turn white and steam is given off.
B Pink crystals are heated. The crystals anhydrous cobalt(II) chloride
turn blue and steam is given off.
C Water is added to a blue solid. hydrated copper(II) sulfate
The blue solid turns pink.
D Water is added to a white solid. anhydrous copper(II) sulfate
The white solid turns blue.

6
15 A student was investigating the reaction between marble chips and dilute hydrochloric acid.
gas syringe
bung
marble
chips 25 cm3 of dilute
hydrochloric acid
Which changes slow down the rate of reaction?
temperature concentration surface area

of acid of acid of marble chips
A decrease decrease decrease

B decrease decrease increase
C increase decrease decrease
D increase increase increase
16 The reactions shown may occur in the air during a thunder-storm.
N2 + O2 o 2NO
2NO + O2 o 2NO2
NO + O3 o NO2 + O2
Which row shows what happens to the reactant molecules in each of these reactions?
N2 NO O3
A oxidised oxidised oxidised

B oxidised oxidised reduced
C reduced reduced oxidised
D reduced reduced reduced
© UCLES 2017 0620/11/M/J/17

7
17 Hydrochloric acid is added to magnesium metal and to sodium carbonate in separate tests.
Which row shows the observations?
magnesium metal sodium carbonate
A effervescence effervescence
B effervescence no reaction
C no reaction effervescence
D no reaction no reaction
18 Which oxide dissolves in water to form a basic solution?
A carbon dioxide
B nitrogen dioxide
C sodium oxide
D sulfur dioxide
19 Which salt preparation uses a burette and a pipette?
A calcium nitrate from calcium carbonate and nitric acid
B copper(II) sulfate from copper(II) hydroxide and sulfuric acid
C potassium chloride from potassium hydroxide and hydrochloric acid

D zinc chloride from zinc and hydrochloric acid
20 Substance X reacts with warm dilute hydrochloric acid to produce a gas which decolourises
acidified aqueous potassium manganate(VII).
Substance X gives a yellow flame in a flame test.
What is X?
A potassium chloride
B potassium sulfite
C sodium chloride
D sodium sulfite

8
Which element is a soft solid that reacts violently with cold water?
A
B
C
D
22 Which element is less reactive than the other members of its group in the Periodic Table?
A astatine
B caesium
C fluorine
D rubidium
23 An element has the following properties.
Ɣ It forms coloured compounds.

Ɣ It acts as a catalyst.
Ɣ It melts at 1539 °C.
In which part of the Periodic Table is the element found?
A Group I
B Group VII
C Group VIII
D transition elements
24 Why are weather balloons sometimes filled with helium rather than hydrogen?
A Helium is found in air.

B Helium is less dense than hydrogen.
C Helium is more dense than hydrogen.
D Helium is unreactive.
© UCLES 2017 0620/11/M/J/17

9
25 Element E:
• forms an alloy
• has a basic oxide
• is below hydrogen in the reactivity series.
What is E?
A carbon
B copper
C sulfur
D zinc
26 Some reactions of three metals and their oxides are shown.
metal reacts with dilute metal oxide

metal
hydrochloric acid reacts with carbon
S no yes
T yes no
U yes yes
least most
reactive reactive
A S T U
B S U T
C T S U
D U T S
27 Which statement about the extraction of iron in a blast furnace is not correct?
A Calcium oxide reacts with acidic impurities.
B Iron(III) oxide is reduced to iron by carbon dioxide.
C Molten iron is formed at the base of the blast furnace.

D The raw materials are hematite, limestone and coke.

10
28 Stainless steel is an alloy of iron and other metals. It is strong and does not rust but it costs much
more than normal steel.
What is not made from stainless steel?
A cutlery
B pipes in a chemical factory
C railway lines
D saucepans
1 2 3
30 Which gas is colourless and poisonous?
A carbon monoxide
B chlorine
C hydrogen
D nitrogen
© UCLES 2017 0620/11/M/J/17

11
31 Two experiments involving water are described.
1 Water turns purple when potassium manganate(VII) is added to it.
2 Adding water to sodium causes the temperature to increase.
Which row describes the role of water in 1 and 2?
1 2
A as a chemical reagent as a chemical reagent

B as a chemical reagent as a solvent
C as a solvent as a chemical reagent
D as a solvent as a solvent
32 In which process is carbon dioxide not formed?
A burning of natural gas

B fermentation
C heating lime
D respiration
33 Which statement is not correct?
A Converting limestone into lime is a thermal decomposition reaction.

B Flue gas desulfurisation is a neutralisation reaction.
C In the extraction of iron, calcium carbonate is converted into calcium oxide.
D Slaked lime is added to soil as a fertiliser.
34 The structures of three substances are shown.
H H H H H H
H C O H H C C O H H C C C O H
H H H H H H
A They are all compounds.

B They are all saturated.
C They all contain oxygen.
D They all contain the same functional group.

12
35 Which fraction of petroleum is not matched to its correct use?
fraction use
A bitumen making roads

B gasoline fuel for cars
C kerosene fuel for ships
D naphtha chemical industry
36 Cracking is an important process in the petroleum industry.
The products of cracking include ......1...... and an ......2...... of ......3...... relative molecular mass
than the ......4...... that was cracked.
Which words complete gaps 1, 2, 3 and 4?
1 2 3 4
A hydrogen alkane greater alkene

B hydrogen alkene smaller alkane
C steam alkane greater alkene
D steam alkene smaller alkane
37 Which compound rapidly decolourises aqueous bromine?
A ethane
B ethanoic acid
C ethanol
D ethene
38 There are two methods for producing ethanol.
method 1 catalytic addition of steam to ethene

method 2 fermentation
A Method 1 produces carbon dioxide.

B Method 1 requires high temperature and pressure.
C Method 2 produces carbon dioxide.
D Method 2 requires a source of sugar.
© UCLES 2017 0620/11/M/J/17

13
39 Which statement about aqueous ethanoic acid is not correct?
A It produces carbon dioxide when it reacts with magnesium carbonate.

B It produces hydrogen when it reacts with magnesium.
C It neutralises magnesium oxide.
D It turns red litmus paper blue.
40 The diagram shows part of the molecule of a polymer.
H H H H H H H H H
C C C C C C C C C
H H H H H H H H H
Which diagram shows the monomer from which this polymer could be manufactured?
A B C D
H H H H H H H
H H H H H H H
© UCLES 2017 0620/11/M/J/17

14
BLANK PAGE
© UCLES 2017 0620/11/M/J/17

15
BLANK PAGE
© UCLES 2017 0620/11/M/J/17

Group
© UCLES 2017
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
16
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/11/M/J/17
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/11
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.
Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level
components.

0620/11 Cambridge IGCSE – Mark Scheme May/June 2017
PUBLISHED
1 B 1
2 B 1
3 C 1
4 B 1
5 B 1
6 C 1
7 B 1
8 C 1
9 A 1
10 A 1
11 B 1
12 C 1
13 C 1
14 D 1
15 A 1
16 B 1
17 A 1
18 C 1
19 C 1
20 D 1
21 D 1
22 A 1
23 D 1
24 D 1
25 B 1
26 B 1
27 B 1
28 C 1
© UCLES 2017 Page 2 of 3

PUBLISHED
29 A 1
30 A 1
31 C 1
32 C 1
33 D 1
34 D 1
35 C 1
36 B 1
37 D 1
38 A 1
39 D 1
40 C 1

CHEMISTRY 0620/21
45 minutes
Soft clean eraser
*8889844006*

IB17 O6_0620_21_VI_LIL/FP
2
1 Small crystals of purple KMnO4 (Mr = 158) and orange K2Cr2O7 (Mr = 294) were placed at the
centres of separate petri dishes filled with agar jelly. They were left to stand under the same
physical conditions.
After some time, the colour of each substance had spread out as shown.
dish 1 dish 2
KMnO4 K2Cr2O7
The lengths of the arrows indicate the relative distances travelled by particles of each substance.
A Diffusion is faster in dish 1 because the mass of the particles is greater.

B Diffusion is faster in dish 2 because the mass of the particles is greater.
C Diffusion is slower in dish 1 because the mass of the particles is smaller.
D Diffusion is slower in dish 2 because the mass of the particles is greater.
2 Pure water has a boiling point of 100 °C and a freezing point of 0 °C.
What is the boiling point and freezing point of a sample of aqueous sodium chloride?
boiling point / °C freezing point / °C
A 98 –2
B 98 2
C 102 –2
D 102 2
© UCLES 2017 0620/21/M/J/17

3
3 A chromatogram obtained from the chromatography of four substances is shown.
Which substance has an Rf value of 0.6?
solvent front
10.5 cm
5.8 cm 6.3 cm
5.5 cm 5.2 cm
baseline
A B C D
4 Sodium reacts with chlorine to form sodium chloride.
Which statements describe what happens to the sodium atoms in this reaction?
1 Sodium atoms form positive ions.

2 Sodium atoms form negative ions.
3 Sodium atoms gain electrons.
4 Sodium atoms lose electrons.
5 Diamond is extremely hard and does not conduct electricity.
Which statement explains these properties?
A It has a lattice of positive carbon ions in a ‘sea of electrons’.

B It has delocalised electrons and each carbon atom forms three covalent bonds with other
carbon atoms.
C It has no delocalised electrons and each carbon atom forms four covalent bonds with other
carbon atoms.
D It has strong ionic bonds between each carbon atom.
6 Which statement about metals is not correct?
A Metals are malleable because the metal ions can slide over one another.
B Metals conduct electricity because electrons can move through the lattice.
C Metals consist of a giant lattice of metal ions in a ‘sea of electrons’.
D Metals have high melting points because of the strong attraction between the metal ions.

4
7 Aluminium reacts with fluorine.
xAl (s) + y F2(g) → zAl F3(s)
Which values of x, y and z balance the equation?
x y z
A 1 2 1
B 2 3 2
C 3 2 3
D 4 3 4
8 Carbon monoxide burns in oxygen to produce carbon dioxide.
2CO(g) + O2(g) → 2CO2(g)
Which mass of carbon dioxide is produced from 14 g of carbon monoxide?
A 22 g B 28 g C 44 g D 88 g
9 Which statement about electrolysis is correct?
A Electrons move through the electrolyte from the cathode to the anode.
B Electrons move towards the cathode in the external circuit.
C Negative ions move towards the anode in the external circuit.
D Positive ions move through the electrolyte towards the anode during electrolysis.
© UCLES 2017 0620/21/M/J/17

5
10 The reactivity series for a number of different metals is shown.

magnesium zinc iron copper silver platinum
The diagram shows different metal strips dipped into an electrolyte.
metal strip metal strip
electrolyte
Which pair of metals produces the highest voltage?
A copper and magnesium

B magnesium and platinum
D silver and platinum
11 Some properties of four fuels are shown in the table.
Which fuel is a gas at room temperature and makes two products when it burns in a plentiful
supply of air?
melting point boiling point

fuel formula
/ °C / °C
A hydrogen H2 –259 –253

B methane CH4 –182 –164
C octane C8H18 –57 126
D wax C31H64 60 400

6

13 Chlorine reacts with ethane to produce chloroethane and hydrogen chloride.
H H H H
H C C H + Cl Cl H C C Cl + H Cl
H H H H
The reaction is exothermic.
The bond energies are shown in the table.
bond energy
bond
in kJ / mol
C–Cl +340
C–C +350
C–H +410
Cl –Cl +240
H–Cl +430
What is the energy change for the reaction?
A –1420 kJ / mol
B –120 kJ / mol
C +120 kJ / mol
D +1420 kJ / mol
© UCLES 2017 0620/21/M/J/17

7
14 When sulfur is heated it undergoes a ......1...... change as it melts.
Further heating causes the sulfur to undergo a ......2...... change and form sulfur dioxide.
1 2
A chemical chemical
B chemical physical
C physical chemical
D physical physical
15 A student was investigating the reaction between marble chips and dilute hydrochloric acid.
gas syringe
bung
marble
chips 25 cm3 of dilute
hydrochloric acid
Which changes slow down the rate of reaction?
temperature concentration surface area

of acid of acid of marble chips
A decrease decrease decrease

B decrease decrease increase
C increase decrease decrease
D increase increase increase

8
16 Nitrogen, hydrogen and ammonia gases are placed inside a container. The container is then
sealed. After some time, an equilibrium forms.
N2(g) + 3H2(g) 2NH3(g)
Which statement describes the equilibrium in this container?
A The amount of ammonia remains constant from the moment the container is sealed.
B The amounts of ammonia, nitrogen and hydrogen in the container are always equal.
C The rate of formation of ammonia is equal to the rate of decomposition of ammonia.
D The rate of formation of ammonia is faster than the rate of decomposition of ammonia.
17 An example of a redox reaction is shown.
Zn + Cu2+ → Zn2+ + Cu
Which statement about the reaction is correct?
A Zn is the oxidising agent and it oxidises Cu2+.

B Zn is the oxidising agent and it reduces Cu2+.
C Zn is the reducing agent and it oxidises Cu2+.
D Zn is the reducing agent and it reduces Cu2+.
18 Zinc oxide is amphoteric.
Which row describes the reactions of zinc oxide?
reaction with
reaction with
aqueous
hydrochloric acid
sodium hydroxide
A key
B = reaction occurs
C = reaction does not occur
D
© UCLES 2017 0620/21/M/J/17

9
19 Which row shows how the hydrogen ion concentration and pH of ethanoic acid compare to those
of hydrochloric acid of the same concentration?
ethanoic acid compared to

hydrochloric acid
hydrogen ion
pH
concentration
A higher higher
B higher lower
C lower higher
D lower lower
20 A pure sample of the insoluble salt barium carbonate can be made using the method given.
step 1 Dissolve barium chloride in water.

step 2 Separately dissolve sodium carbonate in water.
step 3 Mix the two solutions together.
step 4 Filter the mixture.
step 5
step 6 Dry the residue between two sheets of filter paper.
Which instruction is missing from step 5?
A Heat the residue to dryness.

B Heat the residue to the point of crystallisation.
C Place the filtrate in an evaporating basin.
D Wash the residue with water.
21 Substance X reacts with warm dilute hydrochloric acid to produce a gas which decolourises
acidified aqueous potassium manganate(VII).
Substance X gives a yellow flame in a flame test.
What is X?
A potassium chloride
B potassium sulfite
C sodium chloride
D sodium sulfite

10
22 Which element is less reactive than the other members of its group in the Periodic Table?
A astatine
B caesium
C fluorine
D rubidium
23 The elements in Group IV of the Periodic Table are shown.
carbon
silicon
germanium
tin
lead
flerovium
What does not occur in Group IV as it is descended?
A The proton number of the elements increases.

B The elements become more metallic.
C The elements have more electrons in their outer shells.
D The elements have more electron shells.
24 Why are weather balloons sometimes filled with helium rather than hydrogen?
A Helium is found in air.

B Helium is less dense than hydrogen.
C Helium is more dense than hydrogen.
D Helium is unreactive.
© UCLES 2017 0620/21/M/J/17

11
25 Metal X is added to a colourless aqueous solution of the sulfate of metal Y.
A coloured solution is formed and metal Y is deposited at the bottom of the beaker.
Which row describes elements X and Y and their relative reactivity?
type of element relative reactivity
A X is a transition element X is more reactive than Y

B X is a transition element Y is more reactive than X
C Y is a transition element X is more reactive than Y
D Y is a transition element Y is more reactive than X
26 Element E:
• forms an alloy
• has a basic oxide
• is below hydrogen in the reactivity series.
What is E?
A carbon
B copper
C sulfur
D zinc
27 Zinc metal is extracted from its ore zinc blende in a similar method to that used to extract iron
from hematite.
In which way is zinc extraction different from iron extraction?
A Carbon and carbon monoxide are the main reducing agents.

B Hot air at the base of the furnace reacts with coke to keep the furnace hot.
C The metal is removed as a vapour at the top of the furnace.
D The metal oxide is added into the top of the furnace.

12
28 Stainless steel is an alloy of iron and other metals. It is strong and does not rust but it costs much
more than normal steel.
What is not made from stainless steel?
A cutlery
B pipes in a chemical factory
C railway lines
D saucepans
1 2 3
30 Oxides of nitrogen are found in polluted air.
Which statement about oxides of nitrogen is correct?
A Oxides of nitrogen are formed by the reaction of nitrogen with oxygen during the fractional
distillation of liquid air.
B Oxides of nitrogen are formed in a car engine by the reaction of petrol with nitrogen from the
air.
C Oxides of nitrogen are removed from exhaust gases by reaction with carbon dioxide in a
catalytic converter.
D Oxides of nitrogen are removed from exhaust gases by reduction in a catalytic converter.
© UCLES 2017 0620/21/M/J/17

13
31 Photosynthesis and respiration are important natural processes.
A Carbon dioxide is formed by the reaction of glucose with water during photosynthesis.
B Carbon dioxide is removed from the air by respiration.
C Glucose reacts with water to form oxygen during respiration.
D Photosynthesis produces glucose and oxygen.
32 Which row gives the conditions for the Haber process?
pressure
temperature / °C catalyst
/ atm
A 200 2 V2O5
B 200 450 Fe
C 450 200 Fe
D 500 250 V2O5
33 Which statement about sulfuric acid is correct?
A It is made by the Haber process.

B It is made in the atmosphere by the action of lightning.
C It reacts with ammonia to produce a fertiliser.
D It reacts with copper metal to produce hydrogen gas.
34 Which statement is not correct?
A Converting limestone into lime is a thermal decomposition reaction.

B Flue gas desulfurisation is a neutralisation reaction.
C In the extraction of iron, calcium carbonate is converted into calcium oxide.
D Slaked lime is added to soil as a fertiliser.

14
35 Which fraction of petroleum is not matched to its correct use?
fraction use
A bitumen making roads

B gasoline fuel for cars
C kerosene fuel for ships
D naphtha chemical industry
36 The diagram shows the structures of two organic molecules.
H H H H O H
H C C O H H C C C C H
H H H H H H
Which statement about these molecules is not correct?
A They are both alcohols.

B They both produce carbon dioxide and water when they burn in oxygen.
C They contain different functional groups.
D They have the same general formula.
37 The diagram shows part of the molecule of a polymer.
H H H H H H H H H
C C C C C C C C C
H H H H H H H H H
Which diagram shows the monomer from which this polymer could be manufactured?
A B C D
H H H H H H H
H H H H H H H
© UCLES 2017 0620/21/M/J/17

15
38 Ethanol is manufactured by fermentation or by the catalytic addition of steam to ethene.
A Fermentation uses a higher temperature than the catalytic addition of steam to ethene.
B Fermentation uses a non-renewable resource.
C The catalytic addition of steam to ethene produces purer ethanol than fermentation.
D The catalytic addition of steam to ethene uses a biological catalyst.
39 The structure of an ester is shown.
H H O
H C C C H
H H O C H
names of the carboxylic acid and

name of ester
the alcohol used to form the ester
A methyl propanoate methanoic acid and propanol

B methyl propanoate methanol and propanoic acid
C propyl methanoate methanoic acid and propanol
D propyl methanoate methanol and propanoic acid
40 Keratin is a protein that is found in human hair.
Keratin is chemically broken down to produce amino acids.
What is the name of this chemical process?
A catalysis
B hydration
C hydrolysis
D polymerisation
© UCLES 2017 0620/21/M/J/17

Group
© UCLES 2017
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
16
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/21/M/J/17
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/21
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.
components.

PUBLISHED
1 D 1
2 C 1
3 D 1
4 B 1
5 C 1
6 D 1
7 B 1
8 A 1
9 B 1
10 B 1
11 B 1
12 C 1
13 B 1
14 C 1
15 A 1
16 C 1
17 D 1
18 A 1
19 C 1
20 D 1
21 D 1
22 A 1
23 C 1
24 D 1
25 A 1
26 B 1
27 C 1
28 C 1

PUBLISHED
29 A 1
30 D 1
31 D 1
32 C 1
33 C 1
34 D 1
35 C 1
36 C 1
37 C 1
38 C 1
39 B 1
40 C 1


CHEMISTRY 0620/31
1 hour 15 minutes

IB17 06_0620_31/FP
2
1 (a) The electronic structures of five atoms, A, B, C, D and E, are shown.
A B C D E
Answer the following questions about these atoms.

Each atom may be used once, more than once or not at all.
Which atom, A, B, C, D or E,
(i) has a complete outer shell of electrons, .............................. [1]
(ii) has a proton number of 15, .............................. [1]
(iii) has 4 shells containing electrons, .............................. [1]
(iv) is a fluorine atom, .............................. [1]
(v) is an atom of a metallic element? .............................. [1]
(b) Complete the table to show the number of electrons, neutrons and protons in the chlorine atom
and bromide ion shown.
number of electrons number of neutrons number of protons

35
17Cl 17
79
35Br
–
44
[3]
[Total: 8]
© UCLES 2017 0620/31/M/J/17

3
2 (a) The table shows the ions present in a 1000 cm3 sample of polluted river water.
mass present
ion present formula of ion
in mg / 1000 cm3
calcium Ca2+ 2.0

chloride Cl – 1.3
hydrogencarbonate HCO3– 2.0
magnesium Mg2+ 1.0
potassium K+ 4.0
silicate SiO32– 12.0
sodium Na+ 11.0
SO32– 3.0
Answer these questions using the information from the table.
(i) Which positive ion is present in the highest concentration?
....................................................................................................................................... [1]
(ii) State the name of the ion SO32–.
....................................................................................................................................... [1]
(iii) Calculate the mass of silicate ions present in 250 cm3 of this sample.
mass of silicate ions = .............................. mg [1]
(iv) Calculate the mass of solid formed when all the water is evaporated from the 1000 cm3
sample.
mass of solid formed = .............................. mg [1]
(v) Name the compound containing Ca2+ ions and HCO3– ions.
....................................................................................................................................... [1]

4
(b) Describe a test for sodium ions.
test .............................................................................................................................................
result ..........................................................................................................................................
[2]
(c) The formulae of some chlorides are given.
aluminium chloride, Al Cl 3
calcium chloride, CaCl 2
sodium chloride, NaCl
Deduce the formula for magnesium chloride.
.............................................................................................................................................. [1]
(d) Molten calcium chloride can be electrolysed using inert electrodes.
the negative electrode (cathode), ..............................................................................................
the positive electrode (anode). ..................................................................................................

[2]
[Total: 10]
© UCLES 2017 0620/31/M/J/17

5
3 The diagram shows part of the structures of three substances, X, Y and Z, at room temperature and
pressure.
O
C
O O Na+ Cl – Na+ Cl –
C
O
O
O
C O
C
O
C
O
X Y Z
(a) Describe substances X, Y and Z in terms of
● their bonding,
● the arrangement of their particles,
● the motion of their particles.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]

6
(b) A closed gas syringe contains substance X.
end blocked
gas syringe
Describe what happens to the volume of substance X in the syringe when the pressure is
increased. The temperature remains constant. Explain your answer in terms of particles.
....................................................................................................................................................
.............................................................................................................................................. [2]
(c) Substance Z is diamond. Diamond is used in jewellery.
Give one other use of diamond.
.............................................................................................................................................. [1]
(d) Substance Y undergoes physical and chemical changes.
Which two of the following are physical changes? Explain your answer.
A Substance Y dissolves easily in water.

B An aqueous solution of substance Y gives a white precipitate with acidified aqueous
silver nitrate.
C Substance Y melts at 801 C.
D Substance Y reacts with concentrated sulfuric acid.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 11]
© UCLES 2017 0620/31/M/J/17

7
4 Chlorine is an element in Group VII of the Periodic Table.
(a) Chlorine is a diatomic molecule.
Explain what is meant by the term diatomic.
.............................................................................................................................................. [1]
(b) Aqueous chlorine reacts with aqueous potassium bromide.
Cl 2 + 2KBr Br2 + 2KCl
(i) How does this equation show that chlorine is more reactive than bromine?
....................................................................................................................................... [1]
(ii) Aqueous potassium bromide and aqueous potassium chloride are both colourless.
Predict the colour change when aqueous chlorine reacts with aqueous potassium bromide.
....................................................................................................................................... [1]
(iii) Complete the chemical equation for the reaction of aqueous bromine with aqueous
potassium iodide.
Br2 + 2KI ............... + ...............

[2]
(c) Describe a test for iodide ions.
test .............................................................................................................................................
result ..........................................................................................................................................
[2]

8
(d) Chlorine is used to make the polymer PVC.
(i) Give one other use of chlorine.
....................................................................................................................................... [1]
(ii) The monomer used to make PVC is made by the thermal decomposition of dichloroethane.
CH2Cl –CH2Cl CH2=CHCl + HCl
Explain what is meant by the term thermal decomposition.
.............................................................................................................................................
....................................................................................................................................... [2]
(iii) PVC is a non-biodegradable plastic.
Describe two pollution problems caused by non-biodegradable plastics.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
[Total: 12]
© UCLES 2017 0620/31/M/J/17

9
5 Citronellol is found in rose oil.
The structure of citronellol is shown.
CH3 CH3
C
C OH
CH2 H
CH2
CH2 CH2
C
CH3 H
(a) On the structure shown draw a circle around the alcohol functional group. [1]
(b) How many hydrogen atoms are there in one molecule of citronellol?
.............................................................................................................................................. [1]
(c) What feature of the citronellol structure shows that it is unsaturated?
.............................................................................................................................................. [1]

10
(d) The table shows the properties of some alkanes.
number of carbon melting point boiling point density of liquid

alkane
atoms in one molecule in C in C alkane in g / cm3
methane 1 –182 –162 0.466

ethane 2 –183 –88 0.572
propane 3 –188 0.585
butane 4 0 0.601
pentane 5 –130 36 0.626
(i) Describe how the density of the liquid alkanes varies with the number of carbon atoms in
one molecule.
....................................................................................................................................... [1]
(ii) Predict the boiling point of propane.
....................................................................................................................................... [1]
(iii) Why would it be difficult to predict the melting point of butane from the information in the
table?
....................................................................................................................................... [1]
(iv) What is the state of pentane at 30 C? Explain your answer.
.............................................................................................................................................
....................................................................................................................................... [2]
(v) Alkanes are hydrocarbons.
What is the meaning of the term hydrocarbon?
.............................................................................................................................................
....................................................................................................................................... [2]
(vi) Draw the structure of ethane. Show all of the atoms and all of the bonds.
[1]
(vii) Complete the chemical equation for the combustion of propane.
C3H8 + .......O2 .......CO2 + 4H2O

[2]
[Total: 13]
© UCLES 2017 0620/31/M/J/17

11
6 (a) The table shows the properties of some metals.
relative
density melting point relative
metal electrical cost
in g / cm3 in C strength
conductivity
aluminium 2.7 660 7.0 4.0 expensive

iron 7.9 1535 21.0 1.1 cheap
lead 11.3 328 1.5 0.5 expensive
silver 10.5 962 2.0 6.7 very expensive
tungsten 19.4 3420 12.0 2.0 expensive
Use the information in the table to answer the questions.
(i) Which metal would be most useful for making overhead power cables?
Give two reasons for your answer.
metal ................................
reason 1 ..............................................................................................................................
reason 2 ..............................................................................................................................
[2]
(ii) Why is iron and not tungsten used to reinforce concrete?
....................................................................................................................................... [1]
(iii) The front part of a space rocket is called a nose cone. The nose cone gets very hot as the
space rocket moves through the air.
Which metal is best to make a space rocket nose cone? Explain your answer.
....................................................................................................................................... [1]
(b) Tungsten is a transition element.
State two physical properties of transition elements which are not shown by Group I elements.
1 .................................................................................................................................................
2 .................................................................................................................................................
[2]

12
(c) When extremely hot tungsten reacts with oxygen, tungsten(VI) oxide is formed.
Balance the chemical equation for this reaction.
......W + ......O2 2WO3

[2]
(d) Some information about the reaction of four metals with oxygen is given.
cobalt: reacts slowly at high temperatures

iron: thin wire burns when heated strongly
magnesium: burns when heated
tungsten: reacts very slowly at extremely high temperatures
List these metals in order of their reactivity. Put the least reactive metal first.
[2]
(e) The table compares the time taken for reaction of an alloy with ethanoic acid, nitric acid and
phosphoric acid, each at three different concentrations. The time taken for the alloy to decrease
in mass by 1.0 g was measured. All other conditions were kept the same.
time taken for reaction / hours

acid concentration of acid concentration of acid concentration of acid
0.04 mol / dm3 0.02 mol / dm3 0.01 mol / dm3
ethanoic acid 92 190 410

nitric acid 2 6 18
phosphoric acid 19 39 80
(i) How does the concentration of acid affect the rate of reaction?
.............................................................................................................................................
....................................................................................................................................... [1]
(ii) Which acid reacts most rapidly with the alloy?
....................................................................................................................................... [1]
© UCLES 2017 0620/31/M/J/17

13
(iii) Predict how long it would take for the alloy to decrease in mass by 1.0 g using phosphoric
acid of concentration 0.03 mol / dm3.
time taken = .............................. hours [1]
(iv) Suggest which one of these pH values is the pH of concentrated aqueous ethanoic acid.
Draw a circle around the correct answer.
pH 4 pH 7 pH 10 pH 13
[1]
[Total: 14]

14
7 Carbon is an element in Group IV of the Periodic Table. It reacts with oxygen to form carbon dioxide.
(a) The energy level diagram for this reaction is shown.
C + O2
energy
CO2
Explain how this diagram shows that the reaction is exothermic.
....................................................................................................................................................
.............................................................................................................................................. [1]
(b) Carbon monoxide, carbon dioxide and methane are all atmospheric pollutants.
● Give the sources of these gases.

● Describe the effects that both carbon dioxide and methane have on the environment.
● State an adverse effect of carbon monoxide on health.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]
© UCLES 2017 0620/31/M/J/17

15
(c) Calcium carbonate decomposes to form calcium oxide (lime) and carbon dioxide.
(i) State one use of calcium oxide.
....................................................................................................................................... [1]
(ii) Calculate the relative formula mass of calcium carbonate, CaCO3.

Use your Periodic Table to help you.
relative formula mass = .............................. [2]
(d) Carbon and magnesium are both insoluble in water.

Carbon does not react with hydrochloric acid but magnesium reacts to form a soluble salt and
a gas which escapes into the air.
Suggest how you could prepare a pure dry sample of carbon from a mixture of carbon powder
and magnesium powder.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
[Total: 12]
© UCLES 2017 0620/31/M/J/17

Group
© UCLES 2017
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/31/M/J/17
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/31
MARK SCHEME
Maximum Mark: 80
Published
Teachers.
components.

PUBLISHED
1(a)(i) A 1
1(a)(ii) E 1
1(a)(iii) C 1
1(a)(iv) B 1
1(a)(v) C 1
1(b) number of electrons in Br – = 36 1
number of neutrons in Cl = 18 1
number of protons in Cl = 17 AND number of protons in Br – = 35 1
2(a)(i) Na+ / sodium 1
2(a)(ii) sulfite / sulfate(IV) 1
2(a)(iii) 3 (mg) 1
2(a)(iv) 36.3 (mg) 1
2(a)(v) calcium hydrogencarbonate 1
2(b) flame test 1
yellow 1
2(c) MgCl2 1

PUBLISHED
2(d) negative electrode: calcium / Ca 1
positive electrode: chlorine / Cl2 1
3(a) any 5 of: 5

X has covalent bonding
X particles are randomly arranged / irregularly arranged
X particles are moving rapidly / freely / randomly / irregularly
Y has ionic bonding / ionic

Y particles are regularly arranged / lattice / in rows / uniformly arranged
Y particles (only) vibrate / do not move from place to place
Z has covalent bonding

Z particles are regularly arranged / lattice / in a tetrahedral shape
Z particles (only) vibrate / do not move from place to place
3(b) volume gets smaller 1
particles get closer together 1
3(c) drill tips / drills / cutting (tools) 1
3(d) A / substance Y dissolves easily in water 1
C / substance Y melts (at 8015 °C) 1
the change can be reversed by altering the conditions 1

PUBLISHED
4(a) has two atoms in a molecule / two atoms combined 1
4(b)(i) the chlorine has displaced / replaced the bromine (in KBr) 1
4(b)(ii) (from green / colourless) to orange 1
4(b)(iii) I2 1
KBr 1
4(c) add (nitric acid then aqueous) silver nitrate 1
yellow precipitate 1
4(d)(i) water purification / water treatment / killing bacteria / in (swimming) pools / disinfectant 1
4(d)(ii) breaking down of a compound / breaking down of a substance 1
(using) heat 1
4(d)(iii) any 2 distinct pollution problems: 2

• litter OR eyesore
• sticks in gullets OR throats of birds / animals
• blocking of drains OR watercourses
• animals gets trapped OR tangled (in plastic)
• poisonous vapours when burned
• fills landfill sites

PUBLISHED
5(a) circle drawn around the OH group 1
5(b) 20 1
5(c) C=C double bond 1
5(d)(i) increases with an increasing number of carbon atoms ORA 1
5(d)(ii) any value between –88 and 0 (°C) (exclusive of these values) 1
5(d)(iii) there is no (clear) trend / the numbers go down and up 1
5(d)(iv) liquid 1
30 °C is between melting and boiling point / 30 °C is above the melting point and below the boiling point 1
5(d)(v) substance containing carbon and hydrogen 1
only / and no other element 1
5(d)(vi) H H 1
H C C H
H H
5(d)(vii) 3 (CO2) 1
5 (O2) 1

PUBLISHED
6(a)(i) aluminium
low density 1
good electrical conductivity 1
6(a)(ii) iron is cheap(er) / tungsten is (too) expensive 1

OR
iron is strong(er) / tungsten is weaker
6(a)(iii) tungsten because it has a (very) high melting point 1
6(b) any 2 properties: 2

• high melting point / high boiling point
• high density
• hard / strong
• sonorous / rings (when hit)
• ions are coloured / compounds are coloured
6(c) 2 (W) 1
3 (O2) 1
6(d) tungsten < cobalt < iron < magnesium 2

IF full credit is not awarded, allow 1 mark for either a correct sequence apart from a consecutive pair reversed OR for the
whole sequence reversed
6(e)(i) the more concentrated the acid, the greater the rate ORA 1
6(e)(ii) nitric (acid) 1
6(e)(iii) any value between 19 and 39 hours (exclusive of these values) 1
6(e)(iv) pH 4 1

PUBLISHED
7(a) the energy of the reactants is greater than the energy of the products / the product has less energy than the reactants / the 1
arrow is going down (from reactants to product)
7(b) any 2 sources: 5

• carbon monoxide from incomplete combustion of fossil fuels / named fossil fuel / named carbon-containing fuel
• carbon dioxide from combustion of fossil fuels / respiration
• methane from animal flatulence / rice paddy fields / bacteria / decomposition of vegetation / decomposition of
animals
any 3 effects:
• carbon dioxide: global warming / greenhouse effect / acidification of oceans
• methane: global warming / greenhouse effect
• carbon monoxide: poisonous / toxic
7(c)(i) making mortar / whitewash / neutralising (acidic) soils / neutralising acidic lakes / flue gas desulfurisation / steelmaking 1
/ glassmaking / making plaster
7(c)(ii) 100 2
IF full credit is not awarded, allow 1 mark for (Ca =) 40, (C =) 12 and (O =) 16
7(d) add hydrochloric acid to the mixture 1
filter off the carbon 1
wash carbon (with water or other solvent) AND dry in an oven / air dry / leave in air / leave to dry 1

*3843148954*
CHEMISTRY 0620/41


1 hour 15 minutes

IB17 06_0620_41/4RP
2
1 This question is about subatomic particles.
(a) Define the terms
proton number, ...........................................................................................................................
.....................................................................................................................................................
nucleon number. .........................................................................................................................
.....................................................................................................................................................
[3]
(b) Why is the 11H hydrogen atom the only atom to have an identical proton number and nucleon
number?
.....................................................................................................................................................
............................................................................................................................................... [1]
(c) Complete the table to show the number of protons, neutrons and electrons in the atoms and
ions given.

19
F 9
26
Mg 12
31
P3–
87
Sr2+
[6]
(d) (i) Write the formula of the compound formed from fluorine and magnesium.
........................................................................................................................................ [1]
(ii) Write the formula of the compound formed from Sr2+ and P3–.
........................................................................................................................................ [1]
[Total: 12]
© UCLES 2017 0620/41/M/J/17

3
2 Some oxides of some elements are listed.
CO CO2 Na2O MgO Al 2O3
SiO2 P4O10 SO2 Cl 2O7 Cr2O3
(a) Answer the following questions using only oxides from the list. Each oxide may be used once,
Give the formula of an oxide
(i) which is the main cause of acid rain, ...................................................................................
(ii) which would give a solution of pH 14 when added to water, ................................................
(iii) which is coloured, ................................................................................................................
(iv) which is the major impurity in iron ore,.................................................................................
(v) which is amphoteric,.............................................................................................................
(vi) which is neutral. ...................................................................................................................

[6]
(b) Amphoteric oxides and neutral oxides are different from each other.
(i) What is meant by the term amphoteric oxide?
..............................................................................................................................................
........................................................................................................................................ [1]
(ii) What is meant by the term neutral oxide?
..............................................................................................................................................
........................................................................................................................................ [1]
[Total: 8]

4
3 Magnesium sulfate and lead(II) sulfate are examples of salts.
(a) A student prepared magnesium sulfate crystals starting from magnesium carbonate. The
student carried out the experiment in four steps.
step 1
The student added excess magnesium carbonate to a small volume of
dilute sulfuric acid until no more magnesium carbonate would react.
step 2 The student filtered the mixture.
step 3 The student heated the filtrate obtained from step 2 until it was saturated.
step 4 T
he student allowed the hot filtrate to cool to room temperature and then removed
the crystals which formed.
(i) How did the student know when the reaction had finished in step 1?
........................................................................................................................................ [1]
(ii) Name the residue in step 2.
........................................................................................................................................ [1]
(iii) A saturated solution forms in step 3.
What is a saturated solution?
..............................................................................................................................................
........................................................................................................................................ [2]
(iv) Explain why magnesium sulfate crystals form during step 4.
..............................................................................................................................................
........................................................................................................................................ [1]
© UCLES 2017 0620/41/M/J/17

5
(b)
Magnesium sulfate crystals are hydrated. Another student heated some hydrated
magnesium sulfate crystals in a crucible and obtained the following results.
mass of hydrated magnesium sulfate crystals = 4.92 g
mass of water removed = 2.52 g
(i) Calculate the number of moles of water removed.
moles of water = ............................. mol [1]
(ii) Calculate the number of moles of anhydrous magnesium sulfate remaining in the crucible.
The Mr of anhydrous magnesium sulfate is 120.
moles of anhydrous magnesium sulfate = ............................. mol [1]
(iii) Calculate the ratio of moles of anhydrous magnesium sulfate : moles of water. Give your
answer as whole numbers.
ratio = ................ : ................ [1]
(iv) Suggest the formula of hydrated magnesium sulfate crystals.
formula of hydrated magnesium sulfate crystals = ............................................ [2]

6
(c) Lead(II) sulfate, PbSO4, is insoluble.
Describe how you would prepare a pure dry sample of lead(II) sulfate crystals starting from
solutions of lead(II) nitrate and sodium sulfate.
Include a series of key steps in your answer.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [4]
(d) Write the ionic equation for the reaction which takes place between solutions of lead(II) nitrate
and sodium sulfate.
Include state symbols.
............................................................................................................................................... [2]
[Total: 16]
© UCLES 2017 0620/41/M/J/17

7
4 Zinc is a very important metal.
(a) Zinc is extracted from its ore, zinc blende. Zinc blende contains zinc sulfide, ZnS.
Zinc sulfide is converted to zinc oxide in an industrial process.
(i) Describe how zinc sulfide is converted to zinc oxide in this industrial process.
..............................................................................................................................................
........................................................................................................................................ [1]
(ii) Write the chemical equation for this reaction.
........................................................................................................................................ [2]
(b) Zinc oxide is then reduced in a furnace.
(i) Name the substance added to the furnace to reduce the zinc oxide.
........................................................................................................................................ [1]
(ii) Describe how the pure zinc is removed from the furnace and collected.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]

8
(c) When rods of zinc and copper are placed into dilute sulfuric acid as shown, electricity is
generated.
bulb
zinc rod copper rod
(i) Write the ionic half-equation for the reaction occurring at the zinc rod.
........................................................................................................................................ [2]
(ii) Write the ionic half-equation for the reaction occurring at the copper rod.
........................................................................................................................................ [2]
(iii) The copper rod was replaced by an iron rod.
Suggest the change, if any, in the intensity of the light emitted from the bulb and give a
reason for your answer.
change .................................................................................................................................
reason ..................................................................................................................................
..............................................................................................................................................
[2]
[Total: 12]
© UCLES 2017 0620/41/M/J/17

9
5 When barium carbonate is added to dilute hydrochloric acid, carbon dioxide gas is formed.
A student carried out an experiment to measure the volume of gas formed as a reaction proceeds.
The student added a small mass of powdered barium carbonate to an excess of 0.1 mol / dm3
hydrochloric acid. A graph of the results was drawn.
The graph is shown.
400
300
volume
of gas 200
/ cm3
100
0
0 30 60 90 120 150 180 210 240
time / s
(a) Name the two pieces of apparatus needed to take the measurements shown on the graph.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
[1]
(b) On the axes below, sketch a graph to show how the rate of reaction changes as the reaction
proceeds.
Assume the initial rate of reaction is represented by the point at X.
rate of
reaction
0
0 30 60 90 120
time / s
[2]

10
(c) The total volume of gas collected was 180 cm3 at room temperature and pressure.
Calculate the mass, in grams, of barium carbonate used.
BaCO3 + 2HCl BaCl 2 + H2O + CO2
mass of barium carbonate = ............................. g [3]
(d) The original graph has been drawn again.
On the grid, draw the graph expected if the same mass of barium carbonate is added as large
lumps instead of as a powder. All other conditions are the same as in the original experiment.
Explain why your graph is different from the original graph.
400
300
volume
of gas 200
/ cm3
100
0
0 30 60 90 120 150 180 210 240
time / s
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
© UCLES 2017 0620/41/M/J/17

11
(e) The original graph has been drawn again.
On the grid, draw the graph expected if the concentration of dilute hydrochloric acid is changed
from 0.1 mol / dm3 to 0.2 mol / dm3. All other conditions are the same as in the original experiment.
Explain, in terms of particles, why your graph is different from the original graph.
400
300
volume
of gas 200
/ cm3
100
0
0 30 60 90 120 150 180 210 240
time / s
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [4]
(f)
The experiment is changed and the mass of powdered barium carbonate is doubled. All other
conditions are the same as in the original experiment. The acid is still in excess.
Deduce the volume of gas formed at room temperature and pressure, in cm3, in this experiment.
volume of gas = .............................. cm3 [1]
[Total: 13]

12
6 The alkenes and alkanes are both examples of homologous series which are hydrocarbons.
(a) What is meant by the term hydrocarbon?
.....................................................................................................................................................
............................................................................................................................................... [2]
(b) Give three characteristics of an homologous series.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
3 ..................................................................................................................................................
[3]
(c) Name and draw the structure of the second member of the alkene homologous series.
name ...........................................................................................................................................
structure
[2]
(d) Alcohols can be made from alkenes.
Name the reagent and conditions needed to convert an alkene into an alcohol.
.....................................................................................................................................................
............................................................................................................................................... [2]
© UCLES 2017 0620/41/M/J/17

13
(e) The alcohol butanol, CH3CH2CH2CH2OH, can be converted into a carboxylic acid with four
carbon atoms.
(i) Name the carboxylic acid formed from butanol and draw its structure. Show all of the
atoms and all of the bonds.
name ....................................................................................................................................
structure
[2]
(ii) Ethanoic acid can be formed from ethanol by fermentation. It can also be formed by the
addition of a suitable chemical reagent.
Name the reagent needed to convert ethanol into ethanoic acid.
........................................................................................................................................ [2]
(iii)
State the type of chemical change which occurs when ethanol is converted into
ethanoic acid.
........................................................................................................................................ [1]
(f) Describe how a student could prepare the ester methyl ethanoate in a school laboratory.
In your description give
● the names of the two starting organic chemicals,

● the essential reaction conditions needed,
● a chemical equation for the reaction.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [5]
[Total: 19]

14
BLANK PAGE
© UCLES 2017 0620/41/M/J/17

15
BLANK PAGE
© UCLES 2017 0620/41/M/J/17

Group
© UCLES 2017
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/41/M/J/17
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/41
Paper 4 Theory Extended May/June 2017
MARK SCHEME
Maximum Mark: 80
Published
Teachers.
components.

PUBLISHED
1(a) proton number: the number of protons 1
nucleon number: the total number of protons and neutrons 1
nucleon number: in the nucleus / nuclei (of an atom) 1
1(b) (hydrogen is the only atom to have) no neutrons 1
1(c)
19
F 9 10 9
26
Mg 12 14 12
31 3–
P 15 16 18
87 2+
Sr 38 49 36
fluorine protons AND neutrons correct 1
magnesium neutrons AND electrons correct 1
phosphorus protons AND neutrons correct 1
phosphorus electrons correct 1
strontium protons AND neutrons correct 1
strontium electrons correct 1
1(d)(i) MgF2 1
1(d)(ii) Sr3P2 1

PUBLISHED
2(a)(i) SO2 1
2(a)(ii) Na2O 1
2(a)(iii) Cr2O3 1
2(a)(iv) SiO2 1
2(a)(v) Al2O3 / Cr2O3 1
2(a)(vi) CO 1
2(b)(i) an amphoteric oxide will react with acids AND with bases 1
2(b)(ii) a neutral oxide will not react with acids or with bases 1
3(a)(i) no (more) effervescence 1
3(a)(ii) magnesium carbonate 1
3(a)(iii) (a solution in which) no more solute will dissolve 1
at that temperature 1
3(a)(iv) the solubility deceases as the temperature decreases 1
3(b)(i) moles of water = 2.52 / 18 = 0.14 (mol) 1
3(b)(ii) moles of anhydrous magnesium sulfate = 0.02 (mol) 1
3(b)(iii) ratio = 0.02 / 0.02 : 0.14 / 0.02 = 1 : 7 1

PUBLISHED
3(b)(iv) MgSO4.7H2O 2
M1 MgSO4
M2 rest of the formula correct
3(c) mix and stir the two solutions 1
filter (to obtain residue) 1
wash (the residue) using water 1
dry the residue between filter papers / in a warm place 1
3(d) Pb2+(aq) + SO42–(aq) → PbSO4(s) 2
M1 correct species
M2 correct state symbols
4(a)(i) roast in air 1
4(a)(ii) 2ZnS + 3O2 → 2ZnO + 2SO2 2
M1 correct species
M2 correct balancing
4(b)(i) coke 1
4(b)(ii) zinc is vaporised / boiled 1
and is condensed 1

PUBLISHED
4(c)(i) Zn → Zn2+ + 2e– 2
M1 correct species
4(c)(ii) 2H+ + 2e– → H2 2
M1 correct species
4(c)(iii) change: (the intensity would) decrease 1
reason: the difference in reactivity between zinc and iron is less than the difference in reactivity between zinc and copper 1
5(a) (stop-) watch AND syringe 1
5(b) graph starts at X and is a curve with a decreasing gradient 1
graph hits zero rate at 114 ± 6 seconds 1
5(c) M1 moles of carbon dioxide = 180 / 24 000 = 0.0075 1
M2 molar mass of barium carbonate = 197 1
M3 mass of barium carbonate = M1 × M2 = 1.48 (g) 1
5(d) curve starts from (0,0) and has a lower gradient than the original curve 1
because lumps have a lower surface area 1

PUBLISHED
5(e) curve starts from (0,0) and has a steeper gradient than the original curve 1
finishes at the same volume of gas 1
because there are more particles per unit volume / dm3 / cm3 1
because there are more collisions per second / unit time OR a greater collision rate 1
5(f) 360 (cm3) 1
6(a) (compound that) contains carbon and hydrogen 1
and no other elements / only 1
6(b) any 3 from: 3

• same / similar chemical properties
• (same) general formula
• (consecutive members) differ by CH2
• same functional group
• common (allow similar) methods of preparation
• physical properties vary in predictable manner / show trends / gradually change / example of a physical property
variation
6(c) propene 1
structure correctly shown 1
6(d) steam 1
catalyst 1

PUBLISHED
6(e)(i) butanoic acid 1
6(e)(ii) acidified 1
(potassium) manganate(VII) 1
6(e)(iii) oxidation 1
6(f) methanol 1
ethanoic acid 1
catalyst 1
heat 1
CH3COOH + CH3OH → CH3COOCH3 + H2O 1

CHEMISTRY 0620/51

*4461154142*
The teacher responsible for preparing the examination is not allowed to consult the Question Paper before the
The Supervisor’s Report to be included with the scripts is given on pages 7 and 8. Please detach and enclose
it with the scripts. If scripts are despatched in more than one envelope, it is essential that a copy of the
Supervisor’s Results and of the Supervisor’s Report are sent inside each envelope.
caution. Suitable eye protection should be provided.
where relevant.
C corrosive MH moderate hazard

HH health hazard T acutely toxic
F flammable O oxidising
N hazardous to the aquatic environment
If you have any queries regarding these Confidential Instructions, please contact Cambridge stating the Centre
number, the nature of the query and the syllabus number quoted above.
email info@cie.org.uk
phone +44 1223 553554
fax +44 1223 553558
IB17 06_0620_51CI/5RP
2
Question 1
Each candidate will require the following apparatus and chemicals. The labels of solution C and
solution D must not include concentrations.
(a) 2 × 25 cm3 measuring cylinders

(b) 1 × 10 cm3 measuring cylinder
(c) 1 × 50 cm3 burette with stand and clamp
(d) 1 × 250 cm3 conical flask
(e) 100 cm3 of an aqueous solution of hydrated sodium thiosulfate, Na2S2O3.5H2O, of

concentration 0.1 mol / dm3 containing 25 g per dm3, labelled aqueous sodium thiosulfate.
[C] 3 cm3 of 1 mol / dm3 aqueous sodium hydroxide should be added to the above solution to
ensure that it is not acidic.
(f) 50 cm3 of an aqueous solution of potassium iodate, KIO3, containing 6 g per dm3, labelled
solution C
(g) 50 cm3 of an aqueous solution of potassium iodate, KIO3, containing 3 g per dm3, labelled
solution D
[MH] (h) 50 cm3 of sulfuric acid of concentration 1 mol / dm3, labelled dilute sulfuric acid
(i) access to water and distilled water
(j) two samples in stoppered test-tubes of 1 g solid potassium iodide, each labelled 1 g of
potassium iodide
(k) 10 cm3 of starch solution
(l) white tile

(m) funnel for filling burette

© UCLES 2017 0620/51/CI/M/J/17

3
Question 2
Each candidate will require the following apparatus and chemicals. Labels do not need to include
concentrations.
[HH] (a) 0.5 g of basic copper(II) carbonate, CuCO3.Cu(OH)2, labelled solid E
(b) 0.5 g of potassium iodide, KI, labelled solid F

(c) distilled water

(d) apparatus for a flame test

(e) rack of six test-tubes including a hard glass test-tube

(f) stopper to fit test-tubes

(g) limewater and apparatus used to test for carbon dioxide

[MH][N] (h) aqueous silver nitrate of sufficient concentration to give a positive halide test
[MH] (i) dilute sulfuric acid of concentration 1 mol / dm3
[C] (j) dilute nitric acid of concentration 1 mol / dm3
[C] (k) aqueous sodium hydroxide of concentration 1 mol / dm3
[MH][N] (l) aqueous ammonia of concentration 1 mol / dm3
(m) spatulas

(n) splints

(o) teat pipettes

(p) pH indicator paper and chart


4
The Supervisor’s Report is on pages 7 and 8.
© UCLES 2017 0620/51/CI/M/J/17

5

6
© UCLES 2017 0620/51/CI/M/J/17

7
Supervisor’s Report

8
Other cases of individual hardship, e.g. illness, temporary disability, should be reported directly to
Cambridge on the Special Consideration Form.
Declaration (to be signed by the Supervisor)
of the examination.
Name of Centre .......................................................................................................................................
Centre number ...................................................
Signed ...................................................
Name (in block capitals) ........................................................................... (Supervisor)
© UCLES 2017 0620/51/CI/M/J/17

*2045765175*
CHEMISTRY 0620/51


1 hour 15 minutes

Total
IB17 06_0620_51/3RP
2
1 You are going to investigate the reaction between aqueous sodium thiosulfate and two different
aqueous solutions of potassium iodate labelled solution C and solution D.
Instructions

(a) Experiment 1
● ill the burette provided up to the 0.0 cm3 mark with the aqueous sodium thiosulfate.
F
● Use a measuring cylinder to pour 20 cm3 of solution C into a conical flask.
● Add 10 cm3 of dilute sulfuric acid into the flask and 1 g of potassium iodide. Swirl the flask
to mix the contents.
● Add the aqueous sodium thiosulfate slowly from the burette to the flask, and swirl to mix
thoroughly.
● When the contents of the flask are pale yellow, add 1 cm3 of starch solution to the flask.
● Continue to add aqueous sodium thiosulfate slowly to the flask until the solution just turns
colourless.
● Record the burette readings in the table.
(b) Experiment 2
● mpty the conical flask and rinse it with distilled water.

E
● Repeat Experiment 1, using solution D instead of solution C.
● Record the burette readings in the table and complete the table.
Experiment 1 Experiment 2
difference / cm3
[4]
(c) D
escribe the appearance of the solution in the conical flask before adding the aqueous
sodium thiosulfate.
............................................................................................................................................... [1]
(d) B
efore the addition of the starch solution, describe the changes to the colour of the solution in
the conical flask as the aqueous sodium thiosulfate is added.
............................................................................................................................................... [1]
(e) What colour change is observed in the conical flask when the starch solution is added?
from .......................................................... to ....................................................................... [1]
© UCLES 2017 0620/51/M/J/17

3
(f) (i) W
hich solution of potassium iodate, solution C or solution D, is the more concentrated?
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) How many times more concentrated is this solution of potassium iodate?
........................................................................................................................................ [1]
(g) Predict the volume of aqueous sodium thiosulfate which would be needed to react completely
with 30 cm3 of solution D.
.....................................................................................................................................................
............................................................................................................................................... [2]
(h) (i) State two sources of error in the experiments.
1 ...........................................................................................................................................
2 ...........................................................................................................................................
[2]
(ii) Suggest two improvements to reduce the sources of error in (h)(i).
1 ...........................................................................................................................................
2 ...........................................................................................................................................
[2]
[Total: 16]

4
2 You are provided with two solids E and F.

Carry out the following tests on each solid, recording all of your observations at each stage.
tests on solid E
(a) Describe the appearance of solid E.
............................................................................................................................................... [1]
(b) Place a small amount of solid E in a hard glass test-tube. Heat the solid gently then strongly.
.....................................................................................................................................................
............................................................................................................................................... [2]
(c) (i) Place a small amount of solid E in a test-tube and add about 2 cm3 of dilute sulfuric acid.
Test the gas given off.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [3]
(ii) Now gradually add an excess of aqueous ammonia to the mixture in the test-tube.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [3]
(d) C
arry out a flame test on solid E.
............................................................................................................................................... [1]
(e) Identify solid E.
............................................................................................................................................... [2]
© UCLES 2017 0620/51/M/J/17

5
tests on solid F
(f) Describe the appearance of solid F.
............................................................................................................................................... [1]
dd about 4 cm3 of distilled water to about half of solid F in a test-tube and shake the test-tube to
A
dissolve solid F.
Divide the solution into two equal portions in two test-tubes and carry out the following tests.
(g) (i) T
o the first portion of the solution, add an excess of aqueous sodium hydroxide.
........................................................................................................................................ [1]
(ii) T
o the second portion of the solution, add about 1 cm3 of dilute nitric acid and aqueous
silver nitrate.
........................................................................................................................................ [1]
(h) C
arry out a flame test on solid F.
............................................................................................................................................... [1]
(i) Identify solid F.
............................................................................................................................................... [2]
[Total: 18]

6
3 A sample of furniture cleaner contains aqueous sodium chloride, aqueous ammonia and sand.
(a) Give a test to show the presence of ammonia in the mixture.
............................................................................................................................................... [1]
(b) Plan experiments to obtain a sample of
(i) pure water from the mixture, ................................................................................................
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) pure sand from the mixture. .................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [3]
[Total: 6]
© UCLES 2017 0620/51/M/J/17

7

Tests for anions

produced


colourless
colourless solution
copper(II) (Cu2+) light blue ppt., insoluble in excess light blue ppt., soluble in excess,
© UCLES 2017 0620/51/M/J/17

8
Tests for gases Flame tests for metal ions

© UCLES 2017 0620/51/M/J/17

CHEMISTRY 0620/51
MARK SCHEME
Maximum Mark: 40
Published
Teachers.
components.

PUBLISHED
1(b) initial and final readings completed correctly 1
differences completed correctly 1
all readings to 1 d.p. 1
results comparable to the Supervisor’s results 1
1(c) red / brown / amber / orange 1
1(d) (becomes) yellow / orange / paler 1
1(e) yellow to blue / black 1
1(f)(i) solution C is more concentrated 1
a greater volume of thiosulfate was needed 1
1(f)(ii) ratio of the candidate’s differences from the table in (b) 1
1(g) 1.5 × value from table in (b) for Experiment 2 1
unit: cm3 1
1(h)(i) 2 sources of error, e.g.: 2

• using a measuring cylinder to measure solution C / solution D
• only carrying out the experiments once
• going past the end-point
1(h)(ii) 2 meaningful improvements related to (h)(i): 2

• use a pipette / burette
• repeat the experiment
• improvement linked to going past the end-point

PUBLISHED
2(a) green 1
2(b) any 2 from: 2

• turns black
• condensation / drops of liquid formed
• moves / jumps around
2(c)(i) any 3 from: 3

• blue (solution)
• bubbles / fizz
• limewater
• milky
2(c)(ii) blue 1
precipitate 1
(with excess) deep / royal blue solution / clear / precipitate dissolves 1
2(d) blue-green 1

PUBLISHED
2(e) copper / Cu2+ 1
carbonate / CO32– 1
2(f) white 1
2(g)(i) no reaction / no change 1
2(g)(ii) yellow precipitate 1
2(h) lilac 1
2(i) potassium / K+ 1
iodide / I– 1
3(a) (red) litmus turns blue 1
3(b)(i) heat / boil the mixture 1
condense the vapour 1
3(b)(ii) filter / decant 1
wash residue (with water) 1
dry 1

*3090986058*
CHEMISTRY 0620/61


1 hour

IB17 06_0620_61/FP
2
1 A student prepared strontium nitrate crystals.
The diagram shows some of the stages in this preparation.
.........................................
strontium
carbonate
added
strontium nitrate
solution
dilute acid
unreacted
solid
stage 1 stage 2 stage 3
(a) (i) Complete the box to identify the apparatus. [1]
(ii) What is used to add the strontium carbonate to the acid in stage 1?
........................................................................................................................................ [1]
(iii) Name the dilute acid used.
........................................................................................................................................ [1]
(iv) Give one expected observation in stage 2.
........................................................................................................................................ [1]
(b) Why is heat not necessary in stage 2?
............................................................................................................................................... [1]
(c) Which of the reactants is in excess? Explain your answer.
.....................................................................................................................................................
............................................................................................................................................... [2]
(d) Describe how crystals of strontium nitrate could be obtained from the mixture in stage 3.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
[Total: 10]
© UCLES 2017 0620/61/M/J/17

3
2 A student investigated the reaction between aqueous sodium thiosulfate and two different aqueous
solutions of potassium iodate labelled solution C and solution D.
Experiment 1
● burette was filled with aqueous sodium thiosulfate. The initial burette reading was recorded.
A
● Using a measuring cylinder, 20 cm3 of solution C were poured into a conical flask. 10 cm3 of
dilute sulfuric acid and 1 g of potassium iodide were added to the flask to form a solution of
iodine. The flask was swirled to mix the contents.
● Aqueous sodium thiosulfate was slowly added from the burette to the flask and swirled to mix
thoroughly.
● When the contents of the flask turned pale yellow, starch solution was added and the solution
turned blue-black.
● More aqueous sodium thiosulfate was then added slowly to the flask until the solution just
turned colourless. The final burette reading was recorded.
(a) Use the burette diagrams to record the readings in the table and complete the table.
4 37
5 38
6 39
difference / cm3
[2]

4

Experiment 2
● he conical flask was emptied and rinsed with distilled water.

T
● Experiment 1 was repeated using solution D instead of solution C.
(b) Use the burette diagrams to record the readings in the table and complete the table.
3 20
4 21
5 22
difference / cm3
[2]
(c) (i) W
hich solution of potassium iodate, solution C or solution D, is the more concentrated?
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) How many times more concentrated is this solution of potassium iodate?
........................................................................................................................................ [1]
(d) Predict the volume of aqueous sodium thiosulfate which would be needed to react completely
with 30 cm3 of solution D.
.....................................................................................................................................................
............................................................................................................................................... [2]
© UCLES 2017 0620/61/M/J/17

5
(e) (i) State two sources of error in the experiments.
1. ..........................................................................................................................................
2. ..........................................................................................................................................
[2]
(ii) Suggest two improvements to reduce the sources of error in (e)(i).
1. ..........................................................................................................................................
2. ..........................................................................................................................................
[2]
[Total: 13]

6
3 Two solids, E and F, were analysed. Solid F was potassium iodide. Tests were carried out on each
solid. Some of the observations on solid E are shown.
Appearance of solid E. green solid
test 1
Solid E was heated gently then strongly. the solid turned black
test 2
Dilute sulfuric acid was added to solid E. rapid effervescence
The gas given off was tested. limewater turned milky
Excess aqueous ammonia was then added to a pale blue precipitate formed, which then
the mixture in the test-tube. dissolved to form a dark blue solution
test 3
A flame test was carried out on solid E. blue-green colour
(a)
Test 1 states that the solid should be heated gently then strongly.
In terms of safety, explain why it is necessary to heat gently at first.
.....................................................................................................................................................
............................................................................................................................................... [1]
(b) Identify the gas given off in test 2.
............................................................................................................................................... [1]
(c) Identify solid E.
............................................................................................................................................... [2]
© UCLES 2017 0620/61/M/J/17

7
tests on solid F

Complete the expected observations.
(d) Describe the appearance of solid F.
............................................................................................................................................... [1]
Distilled water was added to solid F in a test-tube and shaken to dissolve solid F.
(e) (i) To the first portion of the solution, an excess of aqueous sodium hydroxide was added.
observations .................................................................................................................. [1]
(ii) T
o the second portion of the solution, dilute nitric acid and aqueous silver nitrate were
added.
observations .................................................................................................................. [2]
(f) A flame test was carried out on solid F.
observations ......................................................................................................................... [1]
(g) Describe how you would carry out a flame test.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
[Total: 11]

8
4 A sample of furniture cleaner contains aqueous sodium chloride, aqueous ammonia and sand.
(a) Give a test to show the presence of ammonia in the mixture.
............................................................................................................................................... [1]
(b) Plan an investigation to obtain a sample of
(i) pure water from the mixture, ................................................................................................
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) pure sand from the mixture. .................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [3]
[Total: 6]
© UCLES 2017 0620/61/M/J/17

CHEMISTRY 0620/61
MARK SCHEME
Maximum Mark: 40
Published
Teachers.
components.

PUBLISHED
1(a)(i) stirrer / glass rod 1
1(a)(ii) Spatula 1
1(a)(iii) nitric (acid) 1
1(a)(iv) bubbles / fizz / effervescence 1
1(b) the reaction is (fast) at room temperature 1
1(c) strontium carbonate 1
solid is left behind 1
1(d) filter 1
heat / evaporate 1
to crystallising point / glass rod test / until saturation point 1
2(a) initial and final readings completed correctly: 4.1, 38.3 1
difference completed correctly: 34.2 1
2(b) initial and final readings completed correctly: 3.7, 20.8 1
difference completed correctly: 17.1 1
2(c)(i) solution C is more concentrated 1
a greater volume of thiosulfate was needed 1
2(c)(ii) 2 × as concentrated 1

PUBLISHED
2(d) 1.5 × value from table in (b) for Experiment 2 1
unit: cm3 1
2(e)(i) 2 sources of error, e.g.: 2

• using a measuring cylinder to measure solution C / solution D
• only carrying out the experiments once
• going past the end-point
2(e)(ii) 2 meaningful improvements related to (e)(i): 2

• use a pipette / burette
• repeat the experiment
• improvement linked to going past the end-point
3(a) solid spits out of the tube / the tube might crack 1
3(b) carbon dioxide 1
3(c) copper / Cu2+ 1
carbonate / CO32– 1
3(d) white 1
3(e)(i) no reaction / change 1
3(e)(ii) yellow 1
precipitate 1
3(f) lilac 1

PUBLISHED
3(g) any 2 from: 2

• blue / roaring / hot flame
• use of a splint / wire to introduce the solid into the flame
• use of (concentrated) hydrochloric acid
4(a) (red) litmus turns blue 1
4(b) heat / boil the mixture 1
condense the vapour 1
4(c) filter / decant 1
wash residue (with water) 1
dry 1

CHEMISTRY 0620/11
45 minutes
Soft clean eraser
*1330880521*

IB17 11_0620_11/4RP
2
1 The diagram shows how the arrangement of particles changes when a substance changes state.
Which change of state is shown?
A boiling
B condensation
C evaporation
D sublimation
2 Which method can be used to separate a mixture of salt and water to obtain both parts of the
mixture?
A crystallisation
B distillation
C evaporation
D filtration
3 A student put 25.0 cm3 of dilute hydrochloric acid into a conical flask.
The student added 2.5 g of solid sodium carbonate and measured the change in temperature of
the mixture.
Which apparatus does the student need to use to obtain the most accurate results?
A balance, measuring cylinder, thermometer

B balance, pipette, stopwatch
C balance, pipette, thermometer
D burette, pipette, thermometer
4 Propanone, C3H6O, is a liquid at room temperature.
What is the boiling point of pure propanone?
A –61 °C to –51 °C
B –56 °C
C 51 °C to 61 °C
D 56 °C
© UCLES 2017 0620/11/O/N/17

3
5 Which statement about the boxes P, Q and R is correct?
P Q R
A Box P contains two compounds and box R contains two elements.

B Box P contains two elements and box Q contains a mixture.
C Box P contains two elements and box Q contains one compound.
D Box Q contains two compounds and box R contains a mixture.
6 The number of particles in atoms W, X, Y and Z are shown.
W 6 6 6
X 6 6 7
Y 7 7 7
Z 7 7 8
A W and X are isotopes of carbon.

B X and Y are isotopes of nitrogen.
C X has a mass number of 12.
D Z has an atomic number of 8.
7 Which row describes the type of bonding present in substances 1 and 2?
substance 1 substance 2
A methane has ionic bonding graphite has covalent bonding

B graphite has ionic bonding potassium chloride has covalent bonding
C potassium chloride has ionic bonding methane has covalent bonding
D potassium chloride has ionic bonding graphite has ionic bonding

4
8 Substances with giant covalent structures can be used as lubricants and as cutting tools for hard
materials.
The diagram shows how the atoms are arranged in two giant covalent substances, X and Y.
X Y
key
strong
covalent
bond
weak
attraction
A Only X is used as a cutting tool and only Y is used as a lubricant.

B Only X is used as a lubricant and only Y is used as a cutting tool.
C X and Y are both used as cutting tools.
D X and Y are both used as lubricants.
9 The equation shows the thermal decomposition of magnesium carbonate (Mr = 84).
MgCO3 → MgO + CO2
Which mass of magnesium oxide is formed when 21.0 g of magnesium carbonate are completely
decomposed?
A 1.9 g B 4.0 g C 10.0 g D 40.0 g
© UCLES 2017 0620/11/O/N/17

5
10 Electricity is passed through concentrated aqueous sodium chloride. Inert electrodes are used.
+ –
concentrated
aqueous sodium
chloride
What is formed at the negative electrode?
A chlorine
B hydrogen
C oxygen
D sodium
11 Two chemical processes are described.
● During the combustion of gasoline, energy is ......1...... .

● During the electrolysis of sulfuric acid, energy is ......2...... .
1 2
A given out given out

B given out taken in
C taken in given out
D taken in taken in

6
12 When dilute sulfuric acid reacts with aqueous sodium hydroxide, the temperature of the solution
increases.
Which words describe this reaction?
A endothermic and neutralisation

B endothermic and redox
C exothermic and neutralisation
D exothermic and redox
13 The mass of a beaker and its contents is plotted against time.
Which graph represents what happens when sodium carbonate reacts with an excess of dilute
hydrochloric acid in an open beaker?
A B C D
mass mass mass mass
0 0 0 0
0 time 0 time 0 time 0 time
14 When blue copper(II) sulfate is heated, a white solid and water are formed.
The white solid turns blue and gives out heat when water is added to it.
Which terms describe the blue copper(II) sulfate and the reactions?
the blue
reactions
copper(II) sulfate is
A a mixture can be reversed

B a mixture cannot be reversed
C hydrated can be reversed
D hydrated cannot be reversed
15 Which changes increase the rate of reaction between calcium carbonate and dilute
hydrochloric acid?
1 increasing the concentration of the acid

2 increasing the temperature
3 increasing the size of the pieces of calcium carbonate
© UCLES 2017 0620/11/O/N/17

7
16 The equations for two reactions P and Q are given.
P 2NaNO2 + O2 → 2NaNO3
Q 2HgO → 2Hg + O2
In which of these reactions does oxidation of the underlined substance occur?
P Q
A
B
C
D
17 What is not a typical characteristic of acids?

D They turn blue litmus paper red.
18 Magnesium, phosphorus and chlorine are elements in the same period of the Periodic Table.
Which row describes the type of oxide formed by each of these elements?
magnesium phosphorus chlorine
A acidic acidic basic

B acidic basic basic
C basic acidic acidic
D basic basic acidic
19 Zinc sulfate is made by reacting an excess of zinc oxide with dilute sulfuric acid.
The excess zinc oxide is then removed from the solution.
Which process is used to obtain solid zinc sulfate from the solution?
A crystallisation
B dissolving
C filtration

8
20 What is used to test for chlorine?
A a glowing splint
B damp litmus paper
C limewater
D potassium manganate(VII) solution
21 Which statements about the trends across a period of the Periodic Table are correct?
1 Aluminium is more metallic than sodium.

2 Beryllium is more metallic than carbon.
3 Boron is more metallic than lithium.
4 Magnesium is more metallic than silicon.
22 Astatine is an element in Group VII of the Periodic Table.
Astatine is ......1...... reactive than iodine.
The melting point of astatine is ......2...... than the melting point of iodine.
Astatine is ......3...... in colour than bromine.
1 2 3
A less higher darker

B less lower lighter
C more higher darker
D more lower lighter
23 Which row describes the properties of a typical transition element?
forms coloured can act as

melting point
compounds a catalyst
A high no no
B high yes yes
C low no yes
D low yes no
© UCLES 2017 0620/11/O/N/17

9
25 What is a property of all metals?
A conduct electricity
B hard
C low melting points
D react with water
26 Which material is not involved in the large-scale extraction of iron from iron ore?
A bauxite
B calcium carbonate (limestone)
C carbon (coke)
D hematite

10
27 Some reactions of three metals are listed in the table.
metal reacts with dilute metal oxide is

metal
hydrochloric acid reduced by carbon
P yes no
Q no yes
R yes yes
most least
reactive reactive
A P R Q
B Q P R
C R P Q
D R Q P
28 Which uses of the metals shown are both correct?
aluminium stainless steel
A aircraft bodies cutlery

B car bodies aircraft bodies
C chemical plant food containers
D food containers car bodies
29 The flow chart shows stages in the treatment of river water to produce drinking water.
river settling stage stage drinking

water tank X Y water
What occurs at stages X and Y?
X Y
A distillation chlorination
B distillation filtration
C filtration chlorination
D filtration distillation
© UCLES 2017 0620/11/O/N/17

11
30 Which gas is over 30% of air?
A argon
B carbon dioxide
C nitrogen
D oxygen
31 Iron is a metal that rusts in the presence of oxygen and water.
Mild steel is used for ......1...... and is prevented from rusting by ......2...... .
Stainless steel does not rust. It is produced by ......3...... iron with another metal.
1 2 3
A car bodies greasing covering

B car bodies painting mixing
C cutlery greasing covering
D cutlery painting mixing
32 A mixture produces a gas both when it reacts with an acid and when it reacts with an alkali.
Which ions are present in the mixture?
A ammonium ions and carbonate ions

B ammonium ions and oxide ions
C hydrogen ions and carbonate ions
D hydrogen ions and oxide ions
33 Some marble chips (calcium carbonate) are heated strongly and substances X and Y are formed.
Substance X is a white solid that reacts with water, giving out heat. Substance Y is a colourless
gas.
What are substances X and Y?
X Y
A calcium chloride oxygen

B calcium hydroxide carbon dioxide
C calcium oxide carbon dioxide
D calcium sulfate oxygen

12
34 The structures of some organic molecules are shown.
1 2 3 4
H H CH3 H CH3 H CH3 H
C C H C C H H C C H H C C CH3
H3 C CH3 H CH3 H H H H
Which structures represent an alkane with four carbon atoms?
A 1 only B 2 and 3 C 2 and 4 D 3 and 4
35 Some of the fractions obtained from the fractional distillation of petroleum are used as fuels for
vehicles.
Which two fractions are used as fuels for vehicles?
A bitumen fraction and gasoline fraction

B bitumen fraction and naphtha fraction
C gasoline fraction and kerosene fraction
D kerosene fraction and lubricating fraction
36 Burning fossil fuels releases heat energy.
Which substance is not a fossil fuel?
A coal
B hydrogen
C natural gas
D petroleum

© UCLES 2017 0620/11/O/N/17

13
38 The table shows bonds that are present and bonds that are not present in compound X.
bond
C–C
C=C
C–H
C–O
C=O
O–H
What type of compound is X?
A a carboxylic acid
B an alcohol
C an alkane
D an alkene
39 The diagram shows a reaction sequence.
X Y Z
carbon dioxide
butane ethene ethanol
and water
Which row names the processes X, Y and Z?
X Y Z
A cracking fermentation respiration

B cracking hydration combustion
C distillation fermentation respiration
D distillation hydration combustion

14
40 Molecules of a substance react together as shown.
C C + C C + C C C C C C C C
Which type of reaction has taken place?
A cracking
B oxidation
C polymerisation
D reduction
© UCLES 2017 0620/11/O/N/17

15
BLANK PAGE
© UCLES 2017 0620/11/O/N/17

Group
© UCLES 2017
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
16
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/11/O/N/17
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/11
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2017 series for most
components.

0620/11 Cambridge IGCSE – Mark Scheme October/November
PUBLISHED 2017
1 D 1
2 B 1
3 C 1
4 D 1
5 C 1
6 A 1
7 C 1
8 B 1
9 C 1
10 B 1
11 B 1
12 C 1
13 B 1
14 C 1
15 B 1
16 B 1
17 B 1
18 C 1
19 A 1
20 B 1
21 C 1
22 A 1
23 B 1
24 D 1
25 A 1
26 A 1
27 A 1
28 A 1
29 C 1

PUBLISHED 2017
30 C 1
31 B 1
32 A 1
33 C 1
34 C 1
35 C 1
36 B 1
37 B 1
38 A 1
39 B 1
40 C 1

CHEMISTRY 0620/21
45 minutes
Soft clean eraser
*1790619835*

IB17 11_0620_21/3RP
2
1 Which process causes the greatest increase in the distance between particles?
A condensation
B freezing
C melting
D sublimation
2 A student put 25.0 cm3 of dilute hydrochloric acid into a conical flask.
The student added 2.5 g of solid sodium carbonate and measured the change in temperature of
the mixture.
Which apparatus does the student need to use to obtain the most accurate results?
A balance, measuring cylinder, thermometer

B balance, pipette, stopwatch
D burette, pipette, thermometer
3 The results obtained from a chromatogram are shown.
distance travelled / cm
solvent 5.0
substance X 3.0
substance Y 2.5
Which row gives the Rf values of substance X and substance Y?
Rf (X) Rf (Y)
A 0.5 0.6
B 0.6 0.5
C 1.6 2.0
D 2.0 1.6
© UCLES 2017 0620/21/O/N/17

3
4 Two statements about silicon(IV) oxide are given.
1 It is a hard substance.
2 It has a macromolecular structure with strong covalent bonds.
Which is correct?

C Statement 1 is correct but statement 2 is not correct.
D Statement 2 is correct but statement 1 is not correct.
5 Which statement explains why isotopes of the same element have the same chemical properties?
A They have a different number of neutrons in the nucleus.

B They have the same number of neutrons in the nucleus.
C They have the same number of outer shell electrons.
D They have the same number of protons as neutrons.
6 Which dot-and-cross diagram shows the outer shell electron arrangement in a molecule of
nitrogen?
A B C D
N N N N N N N N
7 The equation for the reaction between barium chloride solution and dilute sulfuric acid is shown.
BaCl 2 + H2SO4 → BaSO4 + 2HCl
Which row shows the state symbols for this equation?
BaCl 2 H2SO4 BaSO4 2HCl
A (aq) (aq) (s) (aq)

B (aq) (l) (s) (aq)
C (l) (aq) (s) (l)
D (aq) (l) (aq) (l)

4
8 A compound is analysed and found to contain 85.7% carbon and 14.3% hydrogen.
What is its empirical formula?
A CH B CH2 C C2H4 D C6H
9 Which statements about the electrolysis of concentrated copper(II) chloride are correct?
2 Electrons move round the external circuit from the cathode to the anode.
10 Which metal combination produces the highest voltage reading in the cells shown?
A B
V V
Fe Cu Zn Cu
C D
V V
Cu Cu Mg Cu
© UCLES 2017 0620/21/O/N/17

5
11 The compound hydrazine is used as a rocket fuel. It has the structural formula shown.
H H
N N
H H
One of the reactions of hydrazine is shown. This reaction is exothermic.
N2H4 → N2 + 2H2
The bond energies are shown in the table.
bond energy
in kJ / mol
H–H +436
N–H +390
N–N +160
N≡N +945
What is the energy change for this reaction?
A –339 kJ / mol B –97 kJ / mol C +97 kJ / mol D +339 kJ / mol
12 Which statement describes an exothermic reaction?
A The energy absorbed for bond breaking is greater than the energy released by bond
formation.
B The energy absorbed for bond breaking is less than the energy released by bond formation.
C The energy released by bond breaking is greater than the energy absorbed for bond
formation.
D The energy released by bond breaking is less than the energy absorbed for bond formation.
13 The mass of a beaker and its contents is plotted against time.
Which graph represents what happens when sodium carbonate reacts with an excess of dilute
hydrochloric acid in an open beaker?
A B C D
mass mass mass mass
0 0 0 0
0 time 0 time 0 time 0 time

6
14 Copper(II) oxide reacts with hydrogen.
CuO + H2 → Cu + H2O
oxidising agent reducing agent
A H2 CuO
B CuO H2
C H2O Cu
D Cu H2O
15 Ethanoic acid reacts slowly with calcium carbonate.
Which statements explain why an increase in temperature increases the rate of the reaction?
1 The activation energy of the reaction is decreased.

2 There is an increase in collision rate.
3 The particles have more energy.
4 There will be fewer successful collisions.
16 Methane reacts with steam to produce hydrogen and carbon monoxide.
The equation for the reaction is shown.
CH4(g) + H2O(g) 3H2(g) + CO(g)
The reaction is reversible. The forward reaction is endothermic.
Which changes in temperature and pressure increase the equilibrium yield of carbon monoxide?
A decrease decrease
B decrease increase
C increase decrease
D increase increase
© UCLES 2017 0620/21/O/N/17

7
17 Some properties of four oxides are listed.
Oxide 1 reacts with both acids and alkalis to form salts.
Oxide 2 reacts with acids to form salts but does not react with alkalis.
Oxide 3 reacts with alkalis to form salts but does not react with acids.
Oxide 4 does not react with acids or alkalis.
Which row describes the oxides?
oxide 1 oxide 2 oxide 3 oxide 4
A amphoteric acidic basic neutral

B amphoteric basic acidic neutral
C neutral acidic basic amphoteric
D neutral basic acidic amphoteric
18 What is not a typical characteristic of acids?

D They turn blue litmus paper red.
19 Zinc sulfate is made by reacting an excess of zinc oxide with dilute sulfuric acid.
The excess zinc oxide is then removed from the solution.
Which process is used to obtain solid zinc sulfate from the solution?
A crystallisation
B dissolving
C filtration
20 What is used to test for chlorine?
A a glowing splint
B damp litmus paper
C limewater
D potassium manganate(VII) solution

8
21 Which statements about the trends across a period of the Periodic Table are correct?
1 Aluminium is more metallic than sodium.

2 Beryllium is more metallic than carbon.
3 Boron is more metallic than lithium.
4 Magnesium is more metallic than silicon.
22 Astatine is an element in Group VII of the Periodic Table.
Astatine is ......1...... reactive than iodine.
The melting point of astatine is ......2...... than the melting point of iodine.
Astatine is ......3...... in colour than bromine.
1 2 3
A less higher darker

B less lower lighter
C more higher darker
D more lower lighter
23 Which row describes the properties of a typical transition element?
forms coloured can act as

melting point
compounds a catalyst
A high no no
B high yes yes
C low no yes
D low yes no
© UCLES 2017 0620/21/O/N/17

9
25 What is a property of all metals?
A conduct electricity
B hard
C low melting points
D react with water
26 Aluminium is extracted by the electrolysis of aluminium oxide.
A Aluminium ions are oxidised at the cathode.

B Carbon dioxide is made at the anode.
C Cryolite is added to lower the melting point of the aluminium oxide.
D The electrodes are made from graphite.
27 Which row describes how the metals are used?
mixed with zinc used to

to form brass galvanise iron
A aluminium tin
B aluminium zinc
C copper tin
D copper zinc

10
28 Information about the nitrates and carbonates of two metals, Q and R, is shown.
appearance solubility in water effect of heat

nitrate of Q white solid soluble colourless gas evolved which
relights a glowing splint
carbonate of Q white solid soluble no reaction
nitrate of R white solid soluble brown gas evolved
carbonate of R white solid insoluble colourless gas evolved which
turns limewater milky
A Q is calcium and R is magnesium.

B Q is magnesium and R is sodium.
C Q is potassium and R is copper.
D Q is sodium and R is calcium.
29 The flow chart shows stages in the treatment of river water to produce drinking water.
river settling stage stage drinking

water tank X Y water
What occurs at stages X and Y?
X Y
A distillation chlorination
B distillation filtration
C filtration chlorination
D filtration distillation
© UCLES 2017 0620/21/O/N/17

11
30 Four iron nails had different metals wrapped around them.
The nails were placed in an open dish filled with water and left for a week.
Which iron nail has no protection against rusting?
A B
wrapped wrapped
in aluminium in copper
D C
wrapped wrapped
in zinc in magnesium
31 Ammonia is made by the Haber process.
N2 + 3H2 2NH3
What are the sources of the nitrogen and hydrogen used in the Haber process?
nitrogen hydrogen
A fertilisers reacting methane with steam

B fertilisers the air
C the air reacting methane with steam
D the air the air
32 Which process does not produce carbon dioxide?
A combustion of alkanes
B photosynthesis
C respiration
D thermal decomposition of limestone

12
33 Which row shows the conditions used in the manufacture of sulfuric acid by the Contact process?
catalyst
/ °C / atm
A 40 200 Fe
B 40 200 V2O5
C 400 2 Fe
D 400 2 V2O5
34 Some marble chips (calcium carbonate) are heated strongly and substances X and Y are formed.
Substance X is a white solid that reacts with water, giving out heat. Substance Y is a colourless
gas.
What are substances X and Y?
X Y
A calcium chloride oxygen

B calcium hydroxide carbon dioxide
C calcium oxide carbon dioxide
D calcium sulfate oxygen
35 The structures of some organic molecules are shown.
1 2 3 4
H H CH3 H CH3 H CH3 H
C C H C C H H C C H H C C CH3
H3 C CH3 H CH3 H H H H
Which structures represent an alkane with four carbon atoms?
A 1 only B 2 and 3 C 2 and 4 D 3 and 4
© UCLES 2017 0620/21/O/N/17

13
36 Some of the fractions obtained from the fractional distillation of petroleum are used as fuels for
vehicles.
Which two fractions are used as fuels for vehicles?
A bitumen fraction and gasoline fraction

B bitumen fraction and naphtha fraction
C gasoline fraction and kerosene fraction
D kerosene fraction and lubricating fraction

38 The diagram shows a reaction sequence.
X Y Z
carbon dioxide
butane ethene ethanol
and water
Which row names the processes X, Y and Z?
X Y Z
A cracking fermentation respiration

B cracking hydration combustion
C distillation fermentation respiration
D distillation hydration combustion
39 Which pair of compounds can be used to prepare CH3CH2COOCH2CH3?
A ethanoic acid and ethanol

B ethanoic acid and propanol
C propanoic acid and ethanol
D propanoic acid and propanol

14
40 The structure of a synthetic polymer is shown.
O O O O O
C C N N C C N N C
H H H H
The structure shows that it is a ......1...... . It is formed by ......2...... polymerisation.
1 2
A polyamide addition
B polyamide condensation
C polyester addition
D polyester condensation
© UCLES 2017 0620/21/O/N/17

15
BLANK PAGE
© UCLES 2017 0620/21/O/N/17

Group
© UCLES 2017
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
16
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/21/O/N/17
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/21
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.
components.

PUBLISHED 2017
1 D 1
2 C 1
3 B 1
4 A 1
5 C 1
6 B 1
7 A 1
8 B 1
9 A 1
10 D 1
11 B 1
12 B 1
13 B 1
14 B 1
15 C 1
16 C 1
17 B 1
18 B 1
19 A 1
20 B 1
21 C 1
22 A 1
23 B 1
24 D 1
25 A 1
26 A 1
27 D 1
28 D 1

PUBLISHED 2017
29 C 1
30 B 1
31 C 1
32 B 1
33 D 1
34 C 1
35 C 1
36 C 1
37 B 1
38 B 1
39 C 1
40 B 1

*8786129582*
CHEMISTRY 0620/31


1 hour 15 minutes

IB17 11_0620_31/3RP
2
1 The diagram shows the structures of five substances, A, B, C, D and E.
A B C
Na+ Br – Na+ Br – F
Br Br
Br – Na+ Br – Na+ F Br F
D E
H H H H
C C Br C C Br
H H H H
nswer the following questions using only the structures in the diagram.
A
Each structure may be used once, more than once or not at all.
(a) Which structure, A, B, C, D or E,
(i) is a diatomic molecule, .................................................................................................. [1]
(ii) contains ions, ................................................................................................................. [1]
(iii) decolourises aqueous bromine, ..................................................................................... [1]
(iv) conducts electricity when molten, .................................................................................. [1]
(v) contains atoms of two different halogens? .................................................................... [1]
(b) Bromine is an element.
What is meant by the term element ?
.....................................................................................................................................................
............................................................................................................................................... [1]
(c) Bromine melts at –7 °C and boils at 59 °C.
hat is the physical state of bromine at –15 °C?

W
.....................................................................................................................................................
............................................................................................................................................... [2]
[Total: 8]
© UCLES 2017 0620/31/O/N/17

3
2 The table shows the composition of the atmosphere of the planet Neptune.
percentage of gas in
gas present
Neptune’s atmosphere
helium 19.5
hydrogen 78.8
methane
other gases 0.2
(a) Complete the table to calculate the percentage of methane in Neptune’s atmosphere. [1]
(b) D
escribe how Neptune’s atmosphere differs from the Earth’s atmosphere.
Give three differences.
1 ..................................................................................................................................................
.....................................................................................................................................................
2 ..................................................................................................................................................
.....................................................................................................................................................
3 ..................................................................................................................................................
.....................................................................................................................................................
[3]
(c) Methane is a covalent compound.
omplete the diagram to show

C
● the arrangement of electrons in a molecule of methane,
● the symbols of the atoms present.
Show outer shell electrons only.
[2]

4
(d) Isotopes of hydrogen are present in Neptune’s atmosphere.
(i) What is meant by the term isotopes?
..............................................................................................................................................
........................................................................................................................................ [1]
(ii) An atom of hydrogen has three nucleons.
educe the number of protons and neutrons present in one atom of this isotope of
D
hydrogen.
number of protons ...............................................................................................................
number of neutrons .............................................................................................................

[2]
(e) Other gases present in Neptune’s atmosphere include ethane and water vapour.
(i) C alculate the relative molecular mass of ethane, C2H6.

relative molecular mass = .............................. [2]
(ii) Describe a chemical test for water.
test .......................................................................................................................................
result ....................................................................................................................................
[2]
[Total: 13]
© UCLES 2017 0620/31/O/N/17

5
3 The following substances are present in a liquid floor cleaner.
coloured dyes
ethanol
preservatives
sodium carbonate
(a) (i) Balance the chemical equation for the complete combustion of ethanol.
C2H5OH + 3O2 ......CO2 + ......H2O

[2]
(ii) Draw the structure of an ethanol molecule showing all of the atoms and all of the bonds.
[2]
(b) Aqueous sodium carbonate is alkaline.
(i) Which one of the following pH values is alkaline?

Put a circle around the correct answer.

[1]
(ii) Aqueous sodium carbonate is colourless.
n excess of aqueous sodium carbonate is added to a solution of dilute sulfuric acid and

A
methyl orange.
Describe the colour change.
from .............................................................. to ............................................................ [2]
(iii) T
he chemical equation for the reaction between sodium carbonate and dilute sulfuric acid
is shown.
Na2CO3 + H2SO4 Na2SO4 + CO2 + H2O
Write the word equation for this reaction.
........................................................................................................................................ [2]

6
(c) Preservatives stop the growth of bacteria and fungi.
State the name of an acidic gas used to preserve food.
............................................................................................................................................... [1]
(d) The coloured dyes in the liquid floor cleaner can be separated using the apparatus shown.
P ..................................................................
Q ..................................................................
(i) Complete the boxes to label P and Q. [2]
(ii) State the name of this method of separation.
........................................................................................................................................ [1]
(iii) O
n the diagram, put an X to show where the mixture of coloured dyes is placed at the start
of the experiment. [1]
[Total: 14]
© UCLES 2017 0620/31/O/N/17

7
4 The table shows the properties of four substances.
electrical electrical
density
substance boiling point conductivity conductivity
in g / cm3
of solid when molten
graphite 2.25
iodine low does not conduct does not conduct 4.93
potassium high conducts 0.86
zinc chloride high does not conduct conducts 2.91
(a) Complete the table to show the electrical conductivity of solid graphite and solid potassium.
[2]
(b) Give one piece of evidence from the table that shows that iodine is a simple covalent substance.
............................................................................................................................................... [1]
(c) What information in the table shows that zinc chloride is an ionic compound?
.....................................................................................................................................................
............................................................................................................................................... [2]
(d) Molten zinc chloride can be electrolysed.
the positive electrode (anode), ...................................................................................................
the negative electrode (cathode). ...............................................................................................

[2]
(e) Aqueous iodine is formed when aqueous chlorine is added to aqueous potassium iodide.
Use ideas about reactivity to explain why this reaction occurs.
.....................................................................................................................................................
............................................................................................................................................... [1]
[Total: 8]

8
5 Titanium is extracted from an ore which contains titanium(IV) oxide, TiO2.
(a) (i) Balance the chemical equation for the first step in this extraction.
TiO2 + ......C + ......Cl 2 TiCl 4 + 2CO

[2]
(ii) Explain why the conversion of carbon to carbon monoxide is an oxidation reaction.
........................................................................................................................................ [1]
(b) T
itanium is a transition element.
Sodium is a Group I element.
Describe two differences in the physical properties of titanium and sodium.
1 ..................................................................................................................................................
.....................................................................................................................................................
2 ..................................................................................................................................................
.....................................................................................................................................................
[2]
(c) T
he properties and relative reactivity with water of some Group I elements are shown in the
table.
element density in g / cm3 melting point in °C relative reactivity with water
lithium 0.53 181
forms bubbles rapidly

sodium 98
but does not burst into flames
forms bubbles very rapidly
potassium 0.86
and bursts into flames
rubidium 1.53 39 reacts explosively
(i) Complete the table

● for the relative reactivity of lithium with water,
● to predict the melting point of potassium.
[2]
(ii) Describe the general trend in the density of the Group I elements.
........................................................................................................................................ [1]
(d) Is lithium oxide an acidic oxide or a basic oxide?

.....................................................................................................................................................
............................................................................................................................................... [1]
[Total: 9]
© UCLES 2017 0620/31/O/N/17

9
6 The diagram shows a fractionating column used for the fractional distillation of petroleum.
refinery gas
gasoline fraction
naphtha fraction
kerosene fraction
diesel oil fraction
fuel oil fraction
lubricating fraction
and bitumen
(a) Describe the fractional distillation of petroleum.

● where the petroleum enters the fractionating column,
● the relative temperatures in the fractionating column (higher or lower),
● the relative boiling points of the fractions (higher or lower),
● the changes in physical state which occur.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [4]

10
(b) Alkenes can be made by cracking the kerosene fraction.
(i) What is meant by the term cracking?
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) When butane is cracked, ethene and gas X are produced.
C4H10 2C2H4 + X
State the name of gas X.
........................................................................................................................................ [1]
(c) Complete the sentence about the bonding in butane.
All the bonds in butane are single ................................ chemical bonds. [1]
(d) Ethene is used to make poly(ethene).
Which one of the following words describes poly(ethene)?

Put a circle around the correct answer.
gas monomer polymer solvent

[1]
[Total: 9]
© UCLES 2017 0620/31/O/N/17

11
7 Bromine is a red-brown liquid which is soluble in cyclohexane.
(a) A few drops of liquid bromine were placed at the bottom of a beaker containing cyclohexane.
After 3 days, a red-brown colour had spread throughout the beaker.
cyclohexane
bromine
at the start after 6 hours after 3 days
Explain these observations using the kinetic particle model.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
(b) The structure of a compound containing bromine is shown.
Br H H O
H C C C C
H Br H O H
(i) D
educe the molecular formula of this compound showing the number of carbon, hydrogen,
oxygen and bromine atoms.
........................................................................................................................................ [1]
(ii) State the name of the C functional group.

O H
........................................................................................................................................ [1]

12
(c) The relative atomic mass of bromine is 80.
Complete the definition of relative atomic mass using terms from the list.
6
12
an atom
an element
a molecule
average
carbon
hydrogen
total
Relative atomic mass is the ................................ mass of naturally occurring atoms
of ................................ on a scale where ................................ of the 12C isotope has
a mass of exactly ................................ units. [4]
(d) Dilute hydrobromic acid reacts with magnesium ribbon.
(i) Suggest three ways of increasing the rate of this reaction.
1 ...........................................................................................................................................
2 ...........................................................................................................................................
3 ...........................................................................................................................................
[3]
(ii) Hydrobromic acid reacts with oxygen. The products are water and bromine.
......HBr + O2 2H2O + 2Br2

[1]
[Total: 13]
© UCLES 2017 0620/31/O/N/17

13
8 Ammonia is manufactured by combining nitrogen and hydrogen at high temperature and pressure.
catalyst
nitrogen + hydrogen ammonia
(a) (i) What is the meaning of the symbol ?
........................................................................................................................................ [1]
(ii) What is the purpose of the catalyst?
........................................................................................................................................ [1]
(b) The graph shows the percentage yield of ammonia at different temperatures.
100
80
60
percentage
yield of
ammonia
40
20
0
0 100 200 300 400 500 600
temperature / °C
(i) Describe how the percentage yield of ammonia changes with temperature.
........................................................................................................................................ [1]
(ii) Deduce the percentage yield of ammonia at 400 °C.
........................................................................................................................................ [1]

14
(c) Copper(II) oxide reacts with ammonia.
copper(II) oxide + ammonia copper + nitrogen + water
When 20 g of copper(II) oxide react with an excess of ammonia, 16 g of copper are formed.
alculate the mass of copper formed when 140 g of copper(II) oxide react with an excess of
C
ammonia.
.............................. g [1]
(d) Ammonia is used in the manufacture of nylon.
Give one use of nylon.
............................................................................................................................................... [1]
[Total: 6]
© UCLES 2017 0620/31/O/N/17

15
BLANK PAGE
© UCLES 2017 0620/31/O/N/17

Group
© UCLES 2017
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/31/O/N/17
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/31
Paper 3 Core Theory October/November 2017
MARK SCHEME
Maximum Mark: 80
Published
Teachers.
components.

PUBLISHED 2017
1(a)(i) A 1
1(a)(ii) B 1
1(a)(iii) D 1
1(a)(iv) B 1
1(a)(v) C 1
1(b) substance containing only one type of atom / substance containing atoms (each) with the same number of protons 1
/ substance which cannot be broken down further by chemical means
1(c) solid 1
–15 °C is below the melting point 1
2(a) 1.5 (%) 1
2(b) any 3 from: 3

• greater percentage of helium (on Neptune) / more helium on Neptune / less helium on Earth
• greater percentage of hydrogen (on Neptune) / more hydrogen on Neptune / no hydrogen on Earth / (very) little
hydrogen on Earth
• no oxygen on Neptune / little oxygen on Neptune (but Earth has 21% oxygen)
• greater percentage of methane (on Neptune) / more methane on Neptune / less methane on Earth / more methane
on Neptune
• more argon on Earth / less argon on Neptune
• no nitrogen on Neptune / little nitrogen on Neptune
2(c) labels ‘C’ and ‘H’ in the correct circles and no non-bonding electrons or extra bonding electrons 1
one pair of electrons in each overlap area 1

PUBLISHED 2017
2(d)(i) atoms of the same element with the same number of protons but a different number of neutrons 1
2(d)(ii) number of protons: 1 1
number of neutrons: 2 1
2(e)(i) 30 2
IF full credit is not awarded, allow 1 mark for (C =) 12 and (H =) 1
2(e)(ii) anhydrous / white copper(II) sulfate 1

OR
anhydrous / blue cobalt(II) chloride
(anhydrous copper(II) sulfate) turns blue 1

OR
(anhydrous cobalt(II) chloride) turns pink
3(a)(i) 2 (CO2) 1
3 (H2O) 1
3(a)(ii) correct structure showing all of the atoms and all of the bonds including O–H 2
IF full credit is not awarded, allow 1 mark for structure with OH
3(b)(i) pH 10 1
3(b)(ii) red / pink 1
to yellow 1
3(b)(iii) sodium carbonate + sulfuric acid → sodium sulfate + carbon dioxide + water 2
IF full credit is not awarded, allow 1 mark for either sodium sulfate OR carbon dioxide + water

PUBLISHED 2017
3(c) sulfur dioxide 1
3(d)(i) P: chromatography paper / filter paper 1
Q: solvent 1
3(d)(ii) chromatography 1
3(d)(iii) X drawn on the baseline 1
4(a) graphite: conducts 1
potassium: conducts 1
4(b) low boiling point 1
4(c) does not conduct when solid but conducts when molten 2
IF full credit is not awarded, allow 1 mark for conducts when molten
4(d) positive electrode (anode): chlorine / Cl2 1
negative electrode (cathode): zinc / Zn 1
4(e) chlorine is more reactive than iodine 1
5(a)(i) 2 (C) 1
2 (Cl2) 1
5(a)(ii) carbon gains oxygen / oxidation number of carbon increases / carbon loses electrons 1

PUBLISHED 2017
5(b) any 2 from: 2

• titanium has a high melting / boiling point ORA
• titanium has a high density ORA
• titanium is hard / strong ORA
5(c)(i) relative reactivity with water: forms bubbles slowly / slower than sodium 1
melting point of potassium: any value between 45–90 (°C) inclusive 1
5(c)(ii) increases down the group / decreases up the group 1
5(d) basic because it is a metal (oxide) 1
6(a) any 4 from: 4

• petroleum vaporised / heated
• petroleum enters the fractionating column at the bottom
• vapours move up the fractionating column
• column is hotter at the bottom / cooler at the top
• idea of vapours condensing in different parts of the fractionating column
• idea of different fractions having different boiling ranges
• fractions (condensing) higher up have lower boiling points ORA
6(b)(i) breaking down / decomposing / splitting hydrocarbons 1
into smaller hydrocarbons / into alkanes and alkenes / by heating / using a high temperature 1
6(b)(ii) hydrogen 1
6(c) covalent 1
6(d) polymer 1

PUBLISHED 2017
7(a) any 3 from: 3

• diffusion
• molecules move (from place to place)
• (molecules move) randomly
• molecules collide
• molecules spread out / mix up
• (bulk) movement of molecules from areas of where they are at higher concentration to where they are at lower
concentration
7(b)(i) C4H6O2Br2 1
7(b)(ii) carboxylic acid 1
7(c) average 1
an element 1
an atom 1
12 1
7(d)(i) increasing the concentration of the acid 1
increasing the temperature 1
using magnesium powder / using smaller pieces of magnesium 1
7(d)(ii) 4 (HBr) 1
8(a)(i) reversible reaction 1
8(a)(ii) speed up the reaction / increase the rate of reaction / speed of reaction faster 1

PUBLISHED 2017
8(b)(i) decreases as the temperature increases ORA 1
8(b)(ii) 28% 1
8(c) 112 (g) 1
8(d) clothing / named clothing / fishing lines 1

*1311966589*
CHEMISTRY 0620/41


1 hour 15 minutes

IB17 11_0620_41/4RP
2
1 The table gives information about five particles. The particles are all atoms or ions.

particle
A 6 8 6
B 12 12 12
C 13 14 10
D 8 8 10
E 11 12 11
nswer the following questions using the information in the table.

A
Each particle may be used once, more than once or not at all.
(a) Which particle, A, B, C, D or E,
(i) is an atom with atomic number 12,
. ...................................................................................................................................... [1]
(ii) is an atom with nucleon number 14,
. ...................................................................................................................................... [1]
(iii) is an ion with a positive charge,
. ...................................................................................................................................... [1]
(iv) has only one electron in its outer shell?
. ...................................................................................................................................... [1]
(b)
D is an ion of an element.
Identify the element and write the formula of D.
.............................................................................................................................................. [2]
[Total: 6]
© UCLES 2017 0620/41/O/N/17

3
2 The graph shows how the temperature of a substance changes as it is cooled over a period of
30 minutes. The substance is a gas at the start.
300 S
250 T
V W
200
X
temperature Y
150
/ °C
Z
100
50
0
0 10 20 30
time / minutes
Each letter on the graph may be used once, more than once or not at all.
(a) Which letter, S, T, V, W, X, Y or Z, shows when
(i) the particles in the substance have the most kinetic energy,
. ...................................................................................................................................... [1]
(ii) the particles in the substance are furthest apart,
. ...................................................................................................................................... [1]
(iii) the substance exists as both a gas and a liquid?
. ...................................................................................................................................... [1]
(b) Use the graph to estimate the freezing point of the substance.
.............................. °C [1]
(c) Name the change of state directly from a solid to a gas.
.............................................................................................................................................. [1]
(d) W
hen smoke is viewed through a microscope, the smoke particles in the air appear to jump
around.
(i) What term describes this movement of the smoke particles?
. ...................................................................................................................................... [1]
(ii) Explain why the smoke particles move in this way.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
[Total: 8]

4
3 (a) W hen magnesium is added to aqueous copper(II) sulfate a reaction occurs.

The ionic equation for the reaction is shown.
Mg + Cu2+ Mg2+ + Cu
(i) Give one change you would observe during this reaction.
. ...................................................................................................................................... [1]
(ii) Explain why this is a redox reaction.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(iii) Identify the oxidising agent in this reaction. Give a reason for your answer.
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(iv) A redox reaction occurs when magnesium is heated with iron(III) oxide.
Write a chemical equation for the reaction between magnesium and iron(III) oxide.
. ...................................................................................................................................... [2]
(b) T
he metal iron and the alloy steel are commonly used materials. A problem with them is that
they rust.
(i) How does painting iron and steel prevent rusting?
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(ii) Magnesium blocks can be attached to the bottom of steel boats.
xplain how the magnesium blocks prevent the whole of the bottom of the boat from
E
rusting.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
© UCLES 2017 0620/41/O/N/17

5
(iii) Replacing the magnesium blocks with copper blocks does not prevent rusting.
Explain why the copper blocks do not prevent rusting.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
[Total: 10]

6
4 (a) Ethanol, C2H5OH, can be made by fermentation.
(i) Complete the chemical equation for the formation of ethanol by fermentation.
C6H12O6 ......C2H5OH + ..............................

[2]
(ii) State two conditions required for fermentation.
1 . .........................................................................................................................................
2 . .........................................................................................................................................
[2]
(b) E
thanol can also be made by the catalytic hydration of ethene. The equation for the reaction is
shown.
C2H4 + H2O C2H5OH
(i) Name a suitable catalyst for this reaction.
. ...................................................................................................................................... [1]
(ii) Calculate the maximum mass of ethanol that can be made from 56 g of ethene.
maximum mass of ethanol = ............................. g [2]
(c) Ethanol can be oxidised to form ethanoic acid.
(i) Name a suitable oxidising agent for this reaction.
. ...................................................................................................................................... [1]
© UCLES 2017 0620/41/O/N/17

7
(ii) A molecule of ethanoic acid has the structure shown.
H O
H C C
H O H
Complete the dot-and-cross diagram to show the electron arrangement in ethanoic acid.

Show outer shell electrons only.
H O
H C C
H O H
[3]
(d) Ethanoic acid is a weak acid.
(i) When referring to an acid, what is meant by the term weak?
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(ii) Describe how you could show that ethanoic acid is a weaker acid than hydrochloric acid.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]

8
(e) Carboxylic acids react with alcohols to make esters.
The structure of an ester is shown.
H H O
H C C C H H H H
H H O C C C C H
H H H H
raw the structures of the carboxylic acid and alcohol from which this ester can be made.
D
Give the names of the carboxylic acid and alcohol.
structure of the carboxylic acid
name of the carboxylic acid ........................................................................................................
structure of the alcohol
name of the alcohol ....................................................................................................................

[4]
[Total: 19]
© UCLES 2017 0620/41/O/N/17

9
olid copper(II) carbonate undergoes thermal decomposition. One of the products of the
5 (a) S
thermal decomposition is copper(II) oxide.
(i) State the colour change of the solid seen during the reaction.
start colour . .........................................................................................................................
end colour . ..........................................................................................................................

[1]
(ii) Write a chemical equation for the thermal decomposition of copper(II) carbonate.
. ...................................................................................................................................... [1]
opper(II) carbonate reacts with dilute nitric acid. One of the products of the reaction is a
(b) C
solution of copper(II) nitrate.
(i) Describe tests for copper(II) ions and nitrate ions. Include the results of the tests.
copper(II) ions .....................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
nitrate ions............................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
[4]
(ii) Copper(II) nitrate undergoes thermal decomposition.
Balance the chemical equation for the thermal decomposition of copper(II) nitrate.
......Cu(NO3)2 ......CuO + ......NO2 + ......O2

[1]

10
(c) N itrogen dioxide, NO2, exists in equilibrium with dinitrogen tetroxide, N2O4.
Nitrogen dioxide is brown and dinitrogen tetroxide is colourless.
2NO2(g) N2O4(g)
brown colourless
(i) A sample of nitrogen dioxide and dinitrogen tetroxide at equilibrium was placed in a closed

gas syringe.
The syringe plunger was pushed in. This increased the pressure in the gas syringe. The
temperature was kept constant.
nitrogen dioxide and

dinitrogen tetroxide
at equilibrium
end blocked
gas syringe
State how the colour of the gas in the syringe changed. Explain your answer in terms of
the position of the equilibrium.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
(ii) A
sealed tube containing nitrogen dioxide and dinitrogen tetroxide at equilibrium was
cooled in an ice bath at constant pressure. The contents of the tube became paler.
Suggest an explanation for this observation in terms of the position of the equilibrium.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
[Total: 12]
© UCLES 2017 0620/41/O/N/17

11
6 Aluminium is extracted from aluminium oxide by electrolysis.
(a) Why is aluminium not extracted by heating aluminium oxide with carbon?
....................................................................................................................................................
.............................................................................................................................................. [1]
(b) Aluminium oxide is an ionic compound with a high melting point.
(i) C
omplete the dot-and-cross diagram to show the electron arrangement in one of the
oxide ions present in aluminium oxide. Include the charge on the oxide ion.
One of the aluminium ions is shown.
3+ ........
Al O
[2]
(ii) The melting point of aluminium oxide is above 2000 °C.
Explain why aluminium oxide has a high melting point.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]

12
(c) Aluminium can be extracted by electrolysis using the apparatus shown.
+ power –
supply
anodes wires
cathode
+ +
aluminium oxide
and cryolite
molten aluminium
(i) Name the type of particle responsible for the transfer of charge in
the wires, .............................................................................................................................
the electrolyte. .....................................................................................................................

[2]
(ii) Give two reasons why cryolite is used.
1 . .........................................................................................................................................
2 . .........................................................................................................................................
[2]
(iii) Write the ionic half-equation for the formation of aluminium during the electrolysis.
. ...................................................................................................................................... [1]
(iv) Explain how carbon dioxide gas is formed at the anodes.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [3]
(d) W
hen a piece of aluminium is placed in dilute hydrochloric acid, there is no immediate visible
reaction.
If the aluminium is left in the dilute hydrochloric acid for several hours, bubbles start to form.
Explain why aluminium does not react immediately with dilute hydrochloric acid.
....................................................................................................................................................
.............................................................................................................................................. [1]
[Total: 14]
© UCLES 2017 0620/41/O/N/17

13

14
7 Copper(II) oxide reacts with dilute hydrochloric acid.
CuO(s) + 2HCl (aq) CuCl 2(aq) + H2O(l)
.00 g of copper(II) oxide were added to 50.0 cm3 of 1.00 mol / dm3 hydrochloric acid. This was an

6
excess of copper(II) oxide.
(a) T
he rate of the reaction can be increased by increasing the concentration of the hydrochloric acid
or by heating it.
(i) In terms of collisions, explain why increasing the concentration of the hydrochloric acid
increases the rate of the reaction.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) In terms of collisions, explain why heating the hydrochloric acid increases the rate of the
reaction.
. ............................................................................................................................................
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
© UCLES 2017 0620/41/O/N/17

15
(b) (i) Calculate the number of moles of copper(II) oxide added to the hydrochloric acid.
moles of copper(II) oxide = ............................. mol [2]
(ii) Calculate the number of moles of hydrochloric acid used.
moles of hydrochloric acid = ............................. mol [1]
(iii) Calculate the mass of copper(II) oxide that did not react.
mass of copper(II) oxide that did not react = ............................. g [2]
rystals of hydrated copper(II) chloride were obtained from the solution at the end of the
(c) C
reaction.
The crystals had the following composition by mass: Cl, 41.52%; Cu, 37.43%; H, 2.34%;
O, 18.71%.
Calculate the empirical formula of the crystals.
empirical formula = ............................. [2]
[Total: 11]
© UCLES 2017 0620/41/O/N/17

Group
© UCLES 2017
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/41/O/N/17
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/41
Paper 4 Extended Theory October/November 2017
MARK SCHEME
Maximum Mark: 80
Published
Teachers.
components.

PUBLISHED 2017
1(a)(i) B 1
1(a)(ii) A 1
1(a)(iii) C 1
1(a)(iv) E 1
1(b) O2– 2
M1 O
M2 2–
2(a)(i) S 1
2(a)(ii) S 1
2(a)(iii) V 1
2(b) any value in the range 130–145 °C 1
2(c) sublimation 1
2(d)(i) Brownian motion 1
2(d)(ii) nitrogen / oxygen / carbon dioxide / air molecules hit / bombard the smoke particles 1
(the bombarding particles) move randomly 1

PUBLISHED 2017
3(a)(i) brown / orange solid (forms / is made) OR solution becomes paler / colourless 1
3(a)(ii) magnesium is oxidised AND copper ions are reduced 1

OR
magnesium loses electrons AND copper ions gain electrons
OR
magnesium increases in oxidation number AND copper decreases in oxidation number
3(a)(iii) Cu2+ OR copper(II) ions OR copper ions 1
gains electrons 1
3(a)(iv) 3Mg + Fe2O3 → 3MgO + 2Fe 2

M1 Fe2O3 AND MgO
M2 fully correct
3(b)(i) prevents air / oxygen AND water from reaching the steel 1
3(b)(ii) magnesium is more reactive than iron / steel 1
the magnesium corrodes (before the iron / steel) 1

OR
the magnesium corrodes preferentially
3(b)(iii) copper is less reactive than iron / steel 1

PUBLISHED 2017
4(a)(i) → 2(C2H5OH) + 2CO2 2

M1 carbon dioxide made as product
M2 balanced

• 37 °C
• anaerobic
• glucose is aqueous
• yeast
4(b)(i) (concentrated) phosphoric acid 1
4(b)(ii) 92 2
If full credit is not awarded, allow 1 mark for Mr of ethene = 28
4(c)(i) (acidified) potassium manganate(VII) OR potassium (di)chromate(VI) 1
4(c)(ii) 3
M1 all shared pairs of electrons correct for single bonds

M2 2 shared pairs of electrons for the C=O bond
M3 total of 8 electrons on each O including 4 non-bonding electrons and no additional non-bonding electrons
4(d)(i) partially ionised / dissociated 1

PUBLISHED 2017
4(d)(ii) M1 (acids) have same concentration 1
M2: measure pH OR describe how to measure pH (such as use Universal Indicator) 2

M3: lower pH corresponds to the stronger acid / hydrochloric acid
OR
M2: add calcium / magnesium / zinc / iron
M3: faster rate of forming bubbles corresponds to the stronger acid / hydrochloric acid
OR
M2: rate of reaction with (metal) carbonate
M3: faster rate of forming bubbles corresponds to the stronger acid / hydrochloric acid
OR
M2: rate of reaction with (named) metal oxide
M3: dissolves faster means that reaction is with the stronger acid / hydrochloric acid
OR
M2: electrical conductivity
M3: greater conductivity corresponds to the stronger acid / hydrochloric acid
OR
M2: add sodium hydroxide (or other named alkali)
M3: greater temperature change corresponds to the stronger acid / hydrochloric acid
4(e) structure of propanoic acid 1
propanoic acid 1
structure of butan-1-ol 1
butan-1-ol 1

PUBLISHED 2017
5(a)(i) start colour: green 1

end colour: black
5(a)(ii) CuCO3 → CuO + CO2 1
5(b)(i) (copper(II) ions) add sodium hydroxide (solution) 1
(copper(II) ions) blue ppt. 1
(nitrate ions) add aluminium AND aqueous sodium hydroxide AND warm 1
ammonia given off / gas turns damp (red) litmus blue 1
5(b)(ii) 2 / 2 / 4 / 1 1
5(c)(i) becomes paler 1
equilibrium moves right 1
(because) fewer moles (of gas) on right 1
5(c)(ii) equilibrium moved right / more N2O4 / less NO2 1
(forward) reaction exothermic 1
6(a) aluminium is more reactive than carbon 1
6(b)(i) oxide ion has an outer shell with six dots and two crosses 1
oxide ion has a charge of 2– 1

PUBLISHED 2017
6(b)(ii) (electrostatic) forces of attraction between ions 1
(are) strong OR require lots of energy to overcome 1
6(c)(i) the wires: electrons 1
the electrolyte: ions 1
6(c)(ii) any 2 from: 2

• increases conductivity
• as a solvent
• lowers the operating temperature
6(c)(iii) Al3+ + 3e– → Al 1
6(c)(iv) oxygen is made at the anode 1
the anodes are made of carbon 1
oxygen (made) reacts with carbon 1
6(d) aluminium coated with layer of (unreactive) aluminium oxide 1
7(a)(i) more particles (of acid) in a given volume / dm3 / cm3 1
more collisions per second / unit time OR greater collision rate 1

PUBLISHED 2017
7(a)(ii) particles have more energy / particles move faster / more collisions per second / more collisions per unit time / greater 1
collision rate
more (of the) particles / collisions have energy greater than the activation energy / more particles have sufficient energy to 1
react / more collisions have sufficient energy to react / a greater percentage of collisions are successful
7(b)(i) 0.075 2
If full credit is not awarded, allow 1 mark for Mr of CuO = 80
7(b)(ii) 0.05 1
7(b)(iii) 4 (g) 2
M1 moles copper(II) oxide that reacted = (0.05 / 2) = 0.025 mol
M2 mass copper(II) oxide = ((0.075 – 0.025) × 80) = 4 g
7(c) Cl2CuH4O2 2
M1 41.52 / 35.5; 37.43 / 64; 2.34 / 1; 18.71 / 16 OR 1.17 : 0.58 : 2.34 : 1.17
M2 appropriate scaling to give whole number ratios

CHEMISTRY 0620/51

*3496257854*
The teacher responsible for preparing the examination is not allowed to consult the Question Paper before the
The Supervisor’s Report to be included with the scripts is given on pages 7 and 8. Please detach and enclose
it with the scripts. If scripts are despatched in more than one envelope, it is essential that a copy of the
Supervisor’s Results and of the Supervisor’s Report are sent inside each envelope.
caution. Suitable eye protection should be provided.
where relevant.

If you have any queries regarding these Confidential Instructions, please contact Cambridge stating the Centre
number, the nature of the query and the syllabus number quoted above.
email info@cie.org.uk
phone +44 1223 553554
fax +44 1223 553558
IB17 11_0620_51CI/FP
2
Question 1
Each candidate will require the following apparatus and chemicals.
(a) 50 cm3 measuring cylinder
(b) stirring thermometer, –10 °C to +110 °C at 1 °C graduations
(c) polystyrene cup
(d) 250 cm3 beaker
[MH] (e) 6 g of ammonium chloride in a stoppered test-tube, labelled solid W
[MH] (f) 3 g of anhydrous calcium chloride in a stoppered test-tube, labelled solid X
The anhydrous calcium chloride should be newly purchased.
(g) stopclock or timer which can measure to an accuracy of 1 s
© UCLES 2017 0620/51/CI/O/N/17

3
Question 2
Each candidate will require the following apparatus and chemicals. Labels do not need to include
concentrations.
(a) 10 cm3 of aqueous chromium(III) nitrate, Cr(NO3)3.9H2O, of concentration 0.1 mol / dm3,

in a stoppered test-tube, labelled solution Y
[MH][N] (b) 10 cm3 of aqueous ammonia of concentration 1 mol / dm3, in a stoppered test-tube,
labelled solution Z
(c) distilled water

(d) red and blue litmus paper

(e) Universal Indicator paper and chart

(f) rack of six test-tubes

(g) stopper to fit test-tubes

(h) boiling tube

[C] (i) aqueous sodium hydroxide of concentration 1 mol / dm3
(j) aluminium foil

[N] (k) aqueous copper(II) sulfate of concentration 0.5 mol / dm3
(l) 10 cm3 measuring cylinder

(m) Bunsen burner and matches

(n) teat pipettes

(o) test-tube holder


4
© UCLES 2017 0620/51/CI/O/N/17

5

6
© UCLES 2017 0620/51/CI/O/N/17

7
Supervisor’s Report

8
2 he Supervisor is invited to report details of any difficulties experienced by candidates, giving

T
names and candidate numbers. The report should include reference to:
Other cases of individual hardship, e.g. illness, temporary disability, should be reported directly to
Cambridge on the Special Consideration form.
Declaration (to be signed by the Supervisor)
of the examination.
Name of Centre .......................................................................................................................................
Centre number ...................................................
Signed ...................................................
Name (in block capitals) ........................................................................... (Supervisor)
© UCLES 2017 0620/51/CI/O/N/17

*4473552331*
CHEMISTRY 0620/61


1 hour

IB17 11_0620_61/3RP
2
1 A student reacted dilute hydrochloric acid with zinc oxide to prepare zinc chloride solution.
The diagram shows part of the procedure.
zinc chloride
solution
unreacted
zinc oxide
funnel
.........................................
(a) Complete the box to name the apparatus. [1]
(b)
Which of the reactants was in excess?
............................................................................................................................................... [1]
(c) (i)
Name the separation process this apparatus is used for.
........................................................................................................................................ [1]
(ii) Suggest why this apparatus would not work.
..............................................................................................................................................
........................................................................................................................................ [1]
(d) Describe how crystals of zinc chloride could be obtained from the zinc chloride solution.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
[Total: 7]
© UCLES 2017 0620/61/O/N/17

3
2
A student investigated the rate of reaction between dilute hydrochloric acid and aqueous
sodium thiosulfate. When these chemicals react they form a precipitate which makes the solution
go cloudy. The formation of this precipitate can be used to show how fast the reaction proceeds.
Five experiments were carried out using the apparatus shown.
eye
10 cm3 of dilute hydrochloric acid
250 cm3 conical flask
sheet of paper with

words printed on it

Experiment 1
● sing a measuring cylinder, 50 cm3 of aqueous sodium thiosulfate were poured into a conical
U
flask. The initial temperature of the solution was measured. The conical flask was placed on a
sheet of paper with words printed on it.
● Using a measuring cylinder, 10 cm3 of dilute hydrochloric acid were added to the solution in the
conical flask and a stopclock was started.
● The time taken for the printed words to disappear from view was measured.
● The final temperature of the mixture was measured.
Experiment 2
● sing a measuring cylinder, 50 cm3 of aqueous sodium thiosulfate were poured into a conical
U
flask. The solution was heated to about 30 °C and the temperature was measured. The conical
flask was placed on a sheet of paper with words printed on it.
● Using a measuring cylinder, 10 cm3 of dilute hydrochloric acid were added to the solution in the
conical flask and a stopclock was started.
● The final temperature of the mixture was measured.
Experiment 3
● xperiment 2 was repeated but the 50 cm3 of aqueous sodium thiosulfate were heated to about
E
40 °C before adding the dilute hydrochloric acid.

Experiment 4
E

Experiment 5
E

4
(a) Calculate the average temperatures and record them in the table.
Use the stopclock diagrams to record the times in the table.
initial final time taken for the

average
experiment temperature temperature stopclock printed words to
temperature
number of the of the diagram disappear from
/ °C
solution / °C mixture / °C view / s
0
seconds
0
1 19 17 45 15 5 15
10
minutes
30
0
0
2 32 30 45 15 5 15
10
30
0
0
3 42 40 45 15 5 15
10
30
0
0
4 54 52 45 15 5 15
10
30
0
0
5 65 61 45 15 5 15
10
30
[3]
© UCLES 2017 0620/61/O/N/17

5
(b) Plot the results of Experiments 1–5 on the grid. Draw a smooth line graph.
240
210
180
150
time taken
for the
printed
words to 120
disappear
from view / s
90
60
30
0
0 10 20 30 40 50 60 70 80
average temperature / °C
[4]
(c) From your graph, deduce the time taken for the printed words to disappear from view when
Experiment 2 was repeated at an initial temperature of 73 °C. The final temperature of the
mixture was 71 °C.
............................................................................................................................................... [3]
(d) Sketch on the grid the graph you would expect if all of the experiments were repeated using
a more dilute solution of aqueous sodium thiosulfate. [1]

6
(e) (i) In which experiment, 1, 2, 3, 4 or 5, was the rate of reaction greatest?
........................................................................................................................................ [1]
(ii) Explain, in terms of particles, why the rate of reaction was greatest in this experiment.
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(f) Suggest and explain the effect on the results of using
(i) a burette to measure the volumes,
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) a 100 cm3 conical flask instead of a 250 cm3 conical flask.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
[Total: 18]
© UCLES 2017 0620/61/O/N/17

7
3 Two solid salts, F and G, were analysed. Solid F was iron(III) nitrate.
Tests were carried out on each solid.
tests on solid F
Solid F was dissolved in distilled water to produce solution F. Solution F was divided into three
equal portions in three test-tubes.
(a) (i) A
few drops of aqueous sodium hydroxide were added to the first portion of solution F until
a change was seen.
observations .................................................................................................................. [2]
(ii) An excess of aqueous sodium hydroxide was then added to the mixture from (a)(i).
observations................................................................................................................... [1]
(b) An excess of aqueous ammonia was added to the second portion of solution F until a change
was seen.
observations.......................................................................................................................... [1]
(c) Aluminium foil and aqueous sodium hydroxide were added to the third portion of solution F.
The mixture was heated and the gas which was produced was tested.
test for gas ..................................................................................................................................
test result ....................................................................................................................................

[2]
(d) Identify the gas produced in (c).
............................................................................................................................................... [1]
tests on solid G
Tests were carried out and the following observations made.
tests on solid G observations
test 1
A flame test was carried out on solid G. red colour
test 2
Dilute nitric acid was added to solid G. rapid effervescence
The gas produced was passed through limewater. limewater turned milky
(e) Identify solid G.
............................................................................................................................................... [2]
[Total: 9]

8
4 Iron, tin and zinc all react with dilute hydrochloric acid to produce hydrogen.
Plan an experiment to determine the order of reactivity of iron, tin and zinc.
You are provided with powdered samples of the metals and common laboratory apparatus.
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
...................................................................................................................................................... [6]
[Total: 6]
© UCLES 2017 0620/61/O/N/17

CHEMISTRY 0620/61
MARK SCHEME
Maximum Mark: 40
Published
Teachers.
components.

PUBLISHED 2017
1(a) evaporating basin / dish 1
1(b) zinc oxide 1
1(c)(i) filtration 1
1(c)(ii) no filter paper 1
1(d) heat / boil / evaporate 1
to crystallising point 1
cool / leave to stand 1
2(a) average temperatures completed for all five experiments: 18, 31, 41, 53, 63 1
times completed for all five experiments: 210, 111, 84, 66, 54 1
all times in seconds 1
2(b) all five points plotted 3
smooth line graph 1
2(c) value from graph for average temperature 72 °C 1
unit (s) 1
shown clearly 1
2(d) line above experimental line 1
2(e)(i) Experiment 5 1

PUBLISHED 2017
2(e)(ii) particles move faster / particles have more energy 1
more (frequent) collisions / greater chance of collisions 1
2(f)(i) more accurate 1
comparison to measuring cylinder 1
2(f)(ii) time shorter / cross disappears faster 1
depth greater 1
3(a)(i) red-brown 1
precipitate 1
3(a)(ii) insoluble / no change 1
3(b) red-brown precipitate 1
3(c) (red) litmus paper 1
turns blue 1
3(d) ammonia 1
3(e) lithium 1
carbonate 1

PUBLISHED 2017
4 reaction with acid method 6
max [6]:
M1 fixed volume of acid
M2 to fixed mass of metal
M3 measure volume of gas / temperature change
M4 named apparatus for the measurement
M5 after time
M6 repeat with other metals
M7 compare / conclude
displacement method
M1 add each metal to named tin salt solution

M2 observe if deposit is formed
M3 results, e.g. Zn and Fe positive
M4 repeat with named iron salt
M5 results, e.g. Zn positive
M6 conclude

CHEMISTRY 0620/11
45 minutes
Soft clean eraser
*9563332168*

IB18 06_0620_11/3RP
2
1 The diagrams show particles in a container.
1 2 3
Which two diagrams show the process of evaporation?
A 1→2 B 1→3 C 2→3 D 3→1
2 Which piece of apparatus is used to measure exactly 26.3 cm3 of a liquid?
A B C D
3 The melting points and boiling points of pure substances W, X and Y are shown.
W X Y
melting point / °C –114 115 –101

boiling point / °C 78 445 –34
The substances are chlorine, ethanol and sulfur.
Which row identifies W, X and Y?
W X Y
A chlorine ethanol sulfur

B ethanol sulfur chlorine
C sulfur chlorine ethanol
D sulfur ethanol chlorine
© UCLES 2018 0620/11/M/J/18

3
4 In which atom is the number of protons equal to the number of neutrons?

40 19 23 16
A Ar B F C Na D O
5 Which row identifies an alloy, a pure metal and a non-metal?
alloy pure metal non-metal
A brass carbon copper

B brass copper carbon
C copper brass carbon
D copper carbon brass
6 A covalent molecule Q contains exactly six shared electrons.
What is Q?
A ammonia, NH3
B chlorine, Cl 2
C methane, CH4
D water, H2O
‘lead’


4
8 The equation for the reaction between magnesium and dilute sulfuric acid is shown.
The Mr of MgSO4 is 120.
Which mass of magnesium sulfate is formed when 12 g of magnesium completely reacts with
dilute sulfuric acid?
A 5g B 10 g C 60 g D 120 g
9 What is observed at each electrode when molten lead(II) bromide is electrolysed using platinum
electrodes?
negative electrode positive electrode
A bubbles of a colourless gas bubbles of a brown gas

B bubbles of a colourless gas bubbles of a colourless gas
C shiny grey liquid bubbles of a brown gas
D shiny grey liquid bubbles of a colourless gas
10 Which gas is used as a fuel?
A argon
B hydrogen
C nitrogen
D oxygen
11 Burning fuels is an exothermic reaction.
What is meant by the term exothermic?
A A gas is produced.
B Energy is released.
C Heat is absorbed.
D The mass of the fuel decreases.
© UCLES 2018 0620/11/M/J/18

5
12 The diagram shows a rate of reaction experiment.
hydrogen
excess dilute
magnesium hydrochloric acid at 25 °C
Increasing the concentration of the acid and increasing the temperature both affect the rate of
reaction.
increase the concentration

increase the temperature
of acid
A decrease rate of reaction decrease rate of reaction

B decrease rate of reaction increase rate of reaction
C increase rate of reaction decrease rate of reaction
D increase rate of reaction increase rate of reaction
13 Water is added to anhydrous copper(II) sulfate.
What happens during the reaction?
A The copper(II) sulfate turns blue and the solution formed gets colder.
B The copper(II) sulfate turns blue and the solution formed gets hotter.
C The copper(II) sulfate turns white and the solution formed gets colder.
D The copper(II) sulfate turns white and the solution formed gets hotter.
14 Which equation shows an oxidation reaction?
A C + O2 → CO2
B CaCO3 → CaO + CO2
C CaO + 2HCl → CaCl 2 + H2O
D N2O4 → 2NO2

6
15 Dilute nitric acid is added to a solid, F.
A gas, G, is produced which is denser than air and extinguishes a burning splint.
What are F and G?
solid F gas G
A calcium hydrogen
B calcium carbonate carbon dioxide
C calcium hydroxide hydrogen
D calcium oxide carbon dioxide
16 Which statement about oxides is correct?
A A solution of magnesium oxide has a pH less than pH 7.

B A solution of sulfur dioxide has a pH greater than pH 7.
C Magnesium oxide reacts with nitric acid to make a salt.
D Sulfur dioxide reacts with hydrochloric acid to make a salt.
17 Which methods are suitable for preparing both zinc sulfate and copper(II) sulfate?
1 reacting the metal oxide with warm dilute aqueous sulfuric acid
2 reacting the metal with dilute aqueous sulfuric acid
3 reacting the metal carbonate with dilute aqueous sulfuric acid
© UCLES 2018 0620/11/M/J/18

7
18 Two salt solutions, X and Y, are tested.
The table shows the results.
test X Y
a few drops of aqueous green precipitate red-brown
sodium hydroxide are added formed precipitate formed
a few drops of dilute nitric acid and no change seen white precipitate
a few drops of barium nitrate are added formed
a few drops of dilute nitric acid and white precipitate no change seen
a few drops of silver nitrate are added formed
What are X and Y?
X Y
A iron(II) chloride iron(III) sulfate

B iron(III) chloride iron(III) sulfate
C iron(II) sulfate iron(III) chloride
D iron(III) sulfate iron(III) chloride
19 Which element is in the same period of the Periodic Table as silicon?
A germanium
B scandium
C sodium
D strontium
20 Which statement about the halogens is correct?
A A sample of bromine reacts with potassium chloride solution.

B A sample of bromine reacts with potassium iodide solution.
C A sample of chlorine has a higher density than a sample of bromine.
D A sample of chlorine is a darker colour than a sample of bromine.

8
21 Which row shows the catalytic activity of transition elements and their compounds?
catalytic activity of catalytic activity of compounds of

transition elements transition elements
A good good
B good poor
C poor good
D poor poor
22 Which statement about the noble gases is not correct?
A Noble gases are diatomic molecules.

B Noble gases are unreactive gases.
C Noble gases have full outer electron shells.
D The noble gas argon is used in lamps.
23 The following statements are made about the metals copper, iron, magnesium and zinc.
1 Their oxides are acidic.

2 They all conduct electricity in the solid state.
3 They all have high melting points.
4 They all react with dilute acids to form hydrogen.
© UCLES 2018 0620/11/M/J/18

9
24 Three metals, X, Y and Z, were reacted with water.
The oxides of the same three metals were also heated strongly with carbon.
The results are shown.
reaction of the metal oxide

metal reaction of the metal with water
with carbon
X vigorous reaction no reaction

with cold water
Y no reaction metal and

carbon dioxide produced
Z no reaction observed with cold water no reaction

but reaction observed with steam
What is a correct conclusion about X, Y and Z?
A X is sodium and Y is magnesium.

B X is the least reactive and Y is the most reactive.
C Z is less reactive than Y.
D Z is magnesium and Y is copper.
25 In a blast furnace, iron ore is mixed with coke and limestone, and heated in hot air.
Compound R is formed. Compound R then reduces the iron ore to iron.
Which equation shows the formation of compound R?
A C + O2 → CO2
B CO2 + C → 2CO
C CaCO3 → CaO + CO2
D CaO + SiO2 → CaSiO3
26 Which statement explains why aluminium is used in the manufacture of aircraft?
A It conducts heat well.

B It has a low density.
C It is a good conductor of electricity.
D It is easy to recycle.

10
27 Dry air is passed over hot copper until all the oxygen has reacted.
dry air copper
heat
The volume of gas at the end of the reaction is 120 cm3.
What is the starting volume of dry air?
A 132 cm3 B 152 cm3 C 180 cm3 D 570 cm3
28 A steel bicycle which had been left outdoors for several months was starting to rust.
What would not reduce the rate of corrosion?
A Remove the rust and paint the bicycle.

B Remove the rust and store the bicycle in a dry shed.
C Remove the rust and wipe the bicycle with a clean, damp cloth.
D Remove the rust and wipe the bicycle with an oily cloth.
1 Household water contains dissolved salts.

A 1, 2, 3 and 4
B 1, 2 and 3 only
C 1, 3 and 4 only
D 2, 3 and 4 only
30 Farmers use fertilisers to replace minerals in the soil that have been removed by the crops they
grow.
Which elements in the soil are replaced by adding fertilisers?
A Ca, P, O B K, O, S C N, K, P D N, O, S
© UCLES 2018 0620/11/M/J/18

11
31 Which statement is correct?
A Atmospheric carbon dioxide is not a cause of climate change.

B Atmospheric methane is produced by respiration.
C Burning natural gas decreases the level of carbon dioxide in the atmosphere.
D Decomposition of vegetation causes an increase in atmospheric methane.
32 Which statement about sulfur and its compounds is not correct?
A Sulfur dioxide is used as a food preservative.
B Sulfur dioxide turns acidified aqueous potassium manganate(VII) from purple to colourless.
C Sulfur forms a basic oxide.

D Sulfur is used in the manufacture of sulfuric acid.
33 Which process is used to convert limestone (calcium carbonate) into lime?
A electrolysis
B fractional distillation
C incomplete combustion
D thermal decomposition
34 Lime is used to treat an industrial waste.
untreated treated
waste waste
lime
Which change occurs in the treatment?
untreated waste treated waste
A acidic → neutral
B alkaline → acidic
C alkaline → neutral
D neutral → acidic

12
35 What is not the correct use of the fraction named?

B gas oil fuel in diesel engines
C kerosene jet fuel
D naphtha making chemicals
36 Four organic compounds are listed.
ethane
ethanoic acid
ethanol
ethene
Which bond do all four compounds contain?
A C–C B C–H C C–O D O–H
37 The first three members of a homologous series are shown.
F F F F F F
F C F F C C F F C C C F
F F F F F F
Why do these molecules represent a homologous series?
A because they contain fluorine and carbon atoms

B because they have saturated bonds
C because they have the same functional group
D because they react differently from each other
38 Which substances can be obtained by cracking hydrocarbons?
A ethanol and ethene

B ethanol and hydrogen
C ethene and hydrogen
D ethene and poly(ethene)
© UCLES 2018 0620/11/M/J/18

13
39 Which reaction is used to make ethanol?
A adding steam to ethene

B addition polymerisation
C fractional distillation of petroleum
D reacting ethene with aqueous bromine
40 Polymers are long-chain molecules made from small molecules linked together.
Four polymers or types of polymer are listed.
1 carbohydrates
2 nylon
3 proteins
4 Terylene
Which of these polymers or types of polymer are synthetic?

14
BLANK PAGE
© UCLES 2018 0620/11/M/J/18

15
BLANK PAGE
© UCLES 2018 0620/11/M/J/18

Group
© UCLES 2018
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/11/M/J/18
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/11
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.
Cambridge International is publishing the mark schemes for the May/June 2018 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and
some Cambridge O Level components.
IGCSE™ is a registered trademark.

PUBLISHED
1 B 1
2 A 1
3 B 1
4 D 1
5 B 1
6 A 1
7 C 1
8 C 1
9 C 1
10 B 1
11 B 1
12 D 1
13 B 1
14 A 1
15 B 1
16 C 1
17 C 1
18 A 1
19 C 1
20 B 1
21 A 1
22 A 1
23 C 1
24 D 1
25 B 1
26 B 1
27 B 1
28 C 1

PUBLISHED
29 C 1
30 C 1
31 D 1
32 C 1
33 D 1
34 A 1
35 A 1
36 B 1
37 C 1
38 C 1
39 A 1
40 D 1

CHEMISTRY 0620/21
45 minutes
Soft clean eraser
*1264661612*

IB18 06_0620_21/3RP
2
1 A student investigated the diffusion of ammonia gas, NH3, and hydrogen chloride gas, HCl.
Two sets of apparatus were set up as shown at room temperature and pressure.
source of damp red source of damp blue

ammonia gas litmus paper hydrogen chloride gas litmus paper
apparatus 1 apparatus 2
The damp red litmus paper in apparatus 1 changed colour after 30 seconds.
How long does it take for the damp blue litmus paper to change colour in apparatus 2?
A 64 seconds
B 30 seconds
C 21 seconds
D The blue litmus paper would not change colour.
2 Chromatography is a technique used to separate coloured dyes.
Which dye has an Rf value of 0.7?
solvent front
baseline
A B C D
dyes
© UCLES 2018 0620/21/M/J/18

3
3 Which piece of apparatus is used to measure exactly 26.3 cm3 of a liquid?
A B C D
‘lead’


4
5 Chlorine exists as two common isotopes, 35Cl and 37Cl.
Information about these two isotopes is shown.

protons neutrons electron shells
35
Cl 17 18 3
37
Cl 17 20 3
Which statement explains why the two isotopes are of the same element?
A Both have the same number of electron shells.

B Both have the same number of protons.
C Both have 7 outer shell electrons.
37
D Cl has 2 more neutrons than 35Cl.
6 Which substance is not a macromolecule?
A diamond
B graphite
C silicon(IV) oxide
D sulfur
7 Copper is a metallic element.
Which statements about copper are correct?
1 Copper is malleable because layers of ions are in fixed positions and cannot move.
2 The structure of copper consists of negative ions in a lattice.
3 Copper conducts electricity because electrons can move through the metal.
4 Electrons hold copper ions together in a lattice by electrostatic attraction.
A 1 and 2 B 2, 3 and 4 C 2 and 3 only D 3 and 4 only
8 The equation for the combustion of ethane is shown.
2C2H6 + 7O2 → 4CO2 + 6H2O
Which volume of carbon dioxide, at room temperature and pressure, is formed when 0.5 moles of
ethane burn?
A 48 dm3 B 24 dm3 C 12 dm3 D 6 dm3
© UCLES 2018 0620/21/M/J/18

5
9 A solution of ethanoic acid, CH3COOH, has a concentration of 2 mol / dm3.
Which statement about this solution is correct?
A 20 g of ethanoic acid is dissolved in 10 cm3 of water.

B 30 g of ethanoic acid is dissolved in 250 cm3 of water.
C 60 g of ethanoic acid is dissolved in 1 dm3 of water.
D 120 g of ethanoic acid is dissolved in 2 dm3 of water.
10 Aqueous copper(II) sulfate is electrolysed using copper electrodes.
A A reduction reaction occurs at the positive electrode.

B The blue colour of the solution becomes darker.
C The concentration of copper ions in the solution decreases.
D The mass of the negative electrode increases.
11 Dilute sulfuric acid is electrolysed using inert electrodes.
What are the ionic half-equations for the reactions that take place at each electrode?
A 2H+ + 2e– → H2 4OH– → 2H2O + O2 + 4e–

B 2H+ + 2e– → H2 4OH– + 4H+ → 4H2O
C 4OH– → 2H2O + O2 + 4e– 2H+ + 2e– → H2
D 4OH– + 4H+ → 4H2O 2H+ + 2e– → H2
12 Plant cells use energy from sunlight for photosynthesis.
Which row describes and explains the energy change that occurs?
type of
explanation
energy change
A endothermic less energy is released making bonds than is absorbed to break bonds
B endothermic more energy is released making bonds than is absorbed to break bonds
C exothermic less energy is released making bonds than is absorbed to break bonds
D exothermic more energy is released making bonds than is absorbed to break bonds

6
13 Hydrogen bromide decomposes to form hydrogen and bromine. The equation is shown.
2HBr(g) → H2(g) + Br2(g)
The bond energies are shown in the table. The reaction is endothermic.
bond energy
bond
in kJ / mol
Br–Br +193
H–Br +366
H–H +436
What is the energy change for the reaction?
A +263 kJ / mol B +103 kJ / mol C –103 kJ / mol D –263 kJ / mol
14 Which row describes the effects of increasing both concentration and temperature on the
collisions between reacting particles?
increasing concentration increasing temperature

A more collisions per second only more collisions per second only
B more collisions per second and more more collisions per second only
collisions with sufficient energy to react
C more collisions per second only more collisions per second and more
collisions with sufficient energy to react
D more collisions per second and more more collisions per second and more
collisions with sufficient energy to react collisions with sufficient energy to react
15 The formation of sulfur trioxide is a reversible reaction.
The equation is shown.
2SO2(g) + O2(g) 2SO3(g)
Which conditions produce the highest equilibrium yield of sulfur trioxide?
A high high
B high low
C low high
D low low
© UCLES 2018 0620/21/M/J/18

7
16 Chlorine displaces iodide ions from potassium iodide.
Cl 2 + 2I– → I2 + 2Cl –
What is the oxidising agent?
A chloride ions
B chlorine
C iodide ions
D iodine
17 Which statement about oxides is correct?
A A solution of magnesium oxide has a pH less than pH 7.

B A solution of sulfur dioxide has a pH greater than pH 7.
C Magnesium oxide reacts with nitric acid to make a salt.
D Sulfur dioxide reacts with hydrochloric acid to make a salt.
18 Which solution has the lowest pH?
A 0.1 mol / dm3 ammonia solution

B 0.1 mol / dm3 ethanoic acid
C 0.1 mol / dm3 lithium hydroxide
D 0.1 mol / dm3 nitric acid
19 A student mixes silver nitrate and barium chloride to form a white precipitate of silver chloride.
2AgNO3 + BaCl 2 → 2AgCl + Ba(NO3)2
Which row describes the solubility of the salts?
soluble insoluble
A silver nitrate barium chloride, barium nitrate
and silver chloride
B silver nitrate and barium chloride barium nitrate and silver chloride
C silver nitrate, barium chloride silver chloride
and barium nitrate
D silver nitrate, barium chloride barium nitrate
and silver chloride

8
20 Which methods are suitable for preparing both zinc sulfate and copper(II) sulfate?
1 reacting the metal oxide with warm dilute aqueous sulfuric acid
2 reacting the metal with dilute aqueous sulfuric acid
3 reacting the metal carbonate with dilute aqueous sulfuric acid
21 Which element is in the same period of the Periodic Table as silicon?
A germanium
B scandium
C sodium
D strontium
22 Which statement about the halogens is correct?
A A sample of bromine reacts with potassium chloride solution.

B A sample of bromine reacts with potassium iodide solution.
C A sample of chlorine has a higher density than a sample of bromine.
D A sample of chlorine is a darker colour than a sample of bromine.
23 Which row shows the catalytic activity of transition elements and their compounds?
catalytic activity of catalytic activity of compounds of

transition elements transition elements
A good good
B good poor
C poor good
D poor poor
24 The following statements are made about the metals copper, iron, magnesium and zinc.
1 Their oxides are acidic.

2 They all conduct electricity in the solid state.
3 They all have high melting points.
4 They all react with dilute acids to form hydrogen.
© UCLES 2018 0620/21/M/J/18

9
25 Silver is a less reactive metal than cadmium.
Cadmium is a less reactive metal than barium.
A Barium does not react when heated with silver oxide.

B Cadmium displaces barium from a solution of barium chloride.
C Cadmium displaces silver from a solution of silver nitrate.
D Cadmium reacts when heated with barium oxide.
26 Aluminium metal is extracted from aluminium oxide using electrolysis.
Which statement about the extraction process is not correct?
A A large amount of electricity is required.

B Molten cryolite is used to dissolve the aluminium oxide.
C Oxygen gas is released which reacts to form carbon dioxide.
D The negative electrodes burn away and have to be replaced.
27 Which statement explains why aluminium is used in the manufacture of aircraft?
A It conducts heat well.

B It has a low density.
C It is a good conductor of electricity.
D It is easy to recycle.
28 Dry air is passed over hot copper until all the oxygen has reacted.
dry air copper
heat
The volume of gas at the end of the reaction is 120 cm3.
What is the starting volume of dry air?
A 132 cm3 B 152 cm3 C 180 cm3 D 570 cm3

10
29 A steel bicycle which had been left outdoors for several months was starting to rust.
What would not reduce the rate of corrosion?
A Remove the rust and paint the bicycle.

B Remove the rust and store the bicycle in a dry shed.
C Remove the rust and wipe the bicycle with a clean, damp cloth.
D Remove the rust and wipe the bicycle with an oily cloth.
1 Household water contains dissolved salts.

A 1, 2, 3 and 4
B 1, 2 and 3 only
C 1, 3 and 4 only
D 2, 3 and 4 only
31 Ammonia is manufactured by reacting hydrogen with nitrogen in the Haber process.
Which row describes the sources of hydrogen and nitrogen and the conditions used in the
manufacture of ammonia in the Haber process?
source of source of temperature of pressure of

hydrogen nitrogen reaction / °C reaction / atm
A air natural gas 250 2

B air natural gas 250 200
C natural gas air 450 2
D natural gas air 450 200
32 Which statements about the carbon cycle are correct?
1 Carbon dioxide is added to the atmosphere by respiration.

2 Carbon dioxide is added to the atmosphere by combustion of coal.
3 Carbon dioxide is removed from the atmosphere by photosynthesis.
© UCLES 2018 0620/21/M/J/18

11
33 Which statement about sulfur and its compounds is not correct?
A Sulfur dioxide is used as a food preservative.
B Sulfur dioxide turns acidified aqueous potassium manganate(VII) from purple to colourless.
C Sulfur forms a basic oxide.

D Sulfur is used in the manufacture of sulfuric acid.
34 Which process is used to convert limestone (calcium carbonate) into lime?
A electrolysis
C incomplete combustion
35 What is not the correct use of the fraction named?

B gas oil fuel in diesel engines
C kerosene jet fuel
D naphtha making chemicals
36 Which reaction is not a reaction which alkenes undergo?
A bromination
B hydration
C hydrogenation
D hydrolysis
37 Which substances can be obtained by cracking hydrocarbons?
A ethanol and ethene

B ethanol and hydrogen
C ethene and hydrogen
D ethene and poly(ethene)

12
38 Ethanol is produced by fermentation or from ethene.
What is a disadvantage of producing ethanol by fermentation?
A Distillation is needed to purify the ethanol produced.

B Fermentation uses glucose from plants.
C Fermentation is catalysed by enzymes in yeast.
D Fermentation occurs at a low temperature and pressure.
39 Which structural formula represents methyl propanoate?
A CH3CH2COOCH3
B CH3COOCH2CH2CH3
C CH3CH2CH2COOCH3
D HCOOCH2CH2CH3
40 Which row describes addition polymerisation and condensation polymerisation?
addition polymerisation condensation polymerisation

A monomers have a C=C double bond monomers have a C=C double bond
and the polymer is the only product and the polymer is the only product
B monomers have a C=C double bond the monomers react to form the
and the polymer is the only product polymer and a small molecule
C the monomers react to form the monomers have a C=C double bond
polymer and a small molecule and the polymer is the only product
D the monomers react to form the the monomers react to form the
polymer and a small molecule polymer and a small molecule
© UCLES 2018 0620/21/M/J/18

13
BLANK PAGE
© UCLES 2018 0620/21/M/J/18

14
BLANK PAGE
© UCLES 2018 0620/21/M/J/18

15
BLANK PAGE
© UCLES 2018 0620/21/M/J/18

Group
© UCLES 2018
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/21/M/J/18
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/21
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.

PUBLISHED
1 A 1
2 D 1
3 A 1
4 C 1
5 B 1
6 D 1
7 D 1
8 B 1
9 B 1
10 D 1
11 C 1
12 A 1
13 B 1
14 C 1
15 B 1
16 B 1
17 C 1
18 D 1
19 C 1
20 C 1
21 C 1
22 B 1
23 A 1
24 C 1
25 C 1
26 D 1
27 B 1
28 B 1

PUBLISHED
29 C 1
30 C 1
31 D 1
32 A 1
33 C 1
34 D 1
35 A 1
36 D 1
37 C 1
38 A 1
39 A 1
40 B 1

*9841440026*
CHEMISTRY 0620/31
1 hour 15 minutes

IB18 06_0620_31/2RP
2
1 The names of eight gases are given.
ammonia
argon
carbon dioxide
helium
hydrogen
methane
neon
sulfur dioxide
(a) Answer the following questions about these gases.

Each gas may be used once, more than once or not at all.
State which gas:
(i) turns damp red litmus paper blue
........................................................................................................................................ [1]
(ii) contributes to the formation of acid rain
........................................................................................................................................ [1]
(iii) is a hydrocarbon which contributes to climate change
........................................................................................................................................ [1]
(iv) is a product of the reaction of copper(II) carbonate with hydrochloric acid
........................................................................................................................................ [1]
(v) is a monatomic gas which has atoms with the electronic structure 2,8,8.
........................................................................................................................................ [1]
(b) (i) Explain why helium and not hydrogen is used to fill party balloons.
........................................................................................................................................ [1]
(ii) Give one use of argon.
........................................................................................................................................ [1]
(c) Carbon dioxide is a compound.
What is meant by the term compound ?
.....................................................................................................................................................
............................................................................................................................................... [1]
© UCLES 2018 0620/31/M/J/18

3
(d) Complete the dot-and-cross diagram to show the electron arrangement in a molecule of
ammonia. Show outer shell electrons only.
H N H
[2]
[Total: 10]

4
2 The table shows the percentage by volume of each of the gases present in the exhaust gases from
a petrol engine.
name percentage by volume

carbon monoxide 1.0
carbon dioxide
hydrogen 0.2
nitrogen 77.0
nitrogen dioxide 0.3
oxygen 0.7
hydrocarbons 0.3
water vapour 5.0
total 100.0
(a) (i) Calculate the percentage by volume of carbon dioxide in the exhaust gases.
..............................% [1]
(ii) Which gas shown in the table is present in the lowest percentage by volume?
........................................................................................................................................ [1]
(iii) Which two elements in the table combine to form nitrogen dioxide?
............................................................... and ................................................................. [1]
(iv) Give the formula for nitrogen dioxide.
........................................................................................................................................ [1]
(v) Where does the nitrogen in the exhaust gases come from?
........................................................................................................................................ [1]
(b)
The carbon monoxide in the exhaust gases comes from the incomplete combustion of
hydrocarbons.
(i) What is meant by the term hydrocarbon?
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) Give one adverse effect of carbon monoxide on health.
........................................................................................................................................ [1]
© UCLES 2018 0620/31/M/J/18

5
(iii) Balance the chemical equation for the complete combustion of pentane.
C5H12 + 8O2 .....CO2 + .....H2O[2]
[Total: 10]

6
3 Limonene is a volatile liquid which smells of oranges.
(a) A teacher placed a beaker of limonene at the front of a classroom.

At first, the students at the back of the classroom could not smell the limonene.
After two minutes, the smell of limonene had spread throughout the classroom.
The air in the classroom was still and calm.
(i) Explain these observations using the kinetic particle model.
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [3]
(ii) The melting point of limonene is –74 °C.

The boiling point of limonene is 176 °C.
What is the physical state of limonene at – 80 °C?

..............................................................................................................................................
........................................................................................................................................ [2]
(b) An enzyme present in peppermint plants is a catalyst for the oxidation of limonene.
State what is meant by the terms:
(i) catalyst
..............................................................................................................................................
........................................................................................................................................ [1]
(ii) oxidation
..............................................................................................................................................
........................................................................................................................................ [1]
© UCLES 2018 0620/31/M/J/18

7
(c) Limonene can be made from a colourless compound called α-terpineol.

The structure of α-terpineol is shown.
H
H
H CH3
C C
H 3C C C C OH
C C H CH3
H H
H H
(i) What feature of the structure of the α-terpineol molecule shows that it is an unsaturated
compound?
........................................................................................................................................ [1]
(ii) Describe how the colour of aqueous bromine changes when an excess of α-terpineol is
added to it.
from .............................................................. to .................................................................

[2]
[Total: 10]

8
4 This question is about iron and its compounds.
(a) The table shows how easy it is to reduce four metal oxides by heating with carbon.
metal oxide ease of reduction with carbon

chromium(III) oxide only reduced above 1700 °C
iron(III) oxide only reduced above 650 °C
magnesium oxide not reduced at 1750 °C
nickel(II) oxide only reduced above 300 °C
Use this information to put the metals in order of their reactivity. Put the least reactive metal
first.
[2]
(b) Iron is a transition element. Potassium is an element in Group I of the Periodic Table.
Describe three ways in which the properties of iron differ from those of potassium.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
3 ..................................................................................................................................................
[3]
(c) Iron wire burns in oxygen.
.....Fe + .....O2 Fe3O4[2]
(d) Pure iron can be made by reducing iron(III) oxide, Fe2O3, with hydrogen.
Fe2O3 + 3H2 2Fe + 3H2O
How does this equation show that iron(III) oxide is reduced?
.....................................................................................................................................................
............................................................................................................................................... [1]
© UCLES 2018 0620/31/M/J/18

9
(e) When iron reacts with dilute hydrochloric acid, iron(II) chloride is formed.
(i) Describe a test for iron(II) ions.
test .......................................................................................................................................
result ....................................................................................................................................
[2]
(ii) Another chloride of iron has the structure shown.
Cl Cl Cl
Fe Fe
Cl Cl Cl
Deduce the molecular formula of this compound showing the number of iron and chlorine
atoms.
........................................................................................................................................ [1]
(f) Some iron nails were placed in bottles under different conditions.
A B C D
moist boiled
air water
water
iron nails anhydrous

calcium chloride
to dry the air
In which bottles will the iron nails not rust?

Give reasons for your answer.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
[Total: 13]

10
5 (a) Complete the sentence about electrolysis using words from the list.
breakdown compound electricity electroplating
element gaseous heat molten
Electrolysis is the .............................. of an ionic .............................. when
.............................. or in aqueous solution by the passage of .............................. .

[4]
(b) Molten zinc iodide can be electrolysed using the apparatus shown.
+ –
On the diagram, label:

●● the anode
●● the cathode
●● the electrolyte [2]
(c) Why are the electrodes made of graphite?
............................................................................................................................................... [1]
(d) Predict the products of the electrolysis of molten zinc iodide at:
the negative electrode ................................................................................................................
the positive electrode. .................................................................................................................

[2]
(e) When chlorine is bubbled through a colourless aqueous solution of zinc iodide, the solution
turns brown.
Name the brown substance. Suggest, using ideas about reactivity of the halogens, why this
reaction occurs.
.....................................................................................................................................................
............................................................................................................................................... [2]
[Total: 11]
© UCLES 2018 0620/31/M/J/18

11
6 This question is about isotopes.
(a) An atom of an isotope of fluorine is represented by the symbol shown.
9F
19
Describe the structure of an atom of this isotope of fluorine.

In your answer, include:
●● the position of the protons, neutrons and electrons in the atom
●● the number of protons, neutrons and electrons present in the atom.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [5]
(b) Complete the sentence about isotopes using words from the list.
atomic compound element ions molecular nucleons
Isotopes are atoms of the same .............................. which have the same
.............................. number but different numbers of .............................. .

[3]
(c) Give one medical use of radioactive isotopes.
............................................................................................................................................... [1]
(d) Which one of the following isotopes is used as a source of energy?

53I 92U 54Xe 30Zn

127 235 131 66
[1]
[Total: 10]

12
7 This question is about Group I elements and their compounds.
(a) The properties of some Group I elements are shown in the table.
boiling point atomic radius relative thermal observations when it

element
/ °C / pm conductivity reacts with cold water
rapid bubbling but does
sodium 883 186 3.9
not burst into flame
very rapid bubbling and
potassium 759 227
bursts into flame
rubidium 688 1.6
caesium 671 265 1.0 explodes
(i) Complete the table to estimate:

●● the relative thermal conductivity of potassium
●● the atomic radius of rubidium.
[2]
(ii) Describe the trend in the boiling points of the Group I elements.
........................................................................................................................................ [1]
(iii) Use the information in the table to predict what you would observe when rubidium reacts
with cold water.
........................................................................................................................................ [1]
(b) Which one of the statements about the formation of a sodium ion from a sodium atom is
correct?
Tick one box.
A sodium atom gains an electron.
A sodium atom loses an electron.
A sodium atom loses a proton.
A sodium atom gains a proton.

[1]
© UCLES 2018 0620/31/M/J/18

13
(c) Is sodium oxide an acidic oxide or a basic oxide?

.....................................................................................................................................................
............................................................................................................................................... [1]
(d) A compound of sodium has the formula C4H5Na.
Calculate the relative formula mass of C4H5Na.

relative formula mass = .............................. [2]
(e) Complete the word equation for the reaction of sodium hydroxide with sulfuric acid.
sodium sulfuric .............................. ..............................

+ +
hydroxide acid
..............................
[2]
[Total: 10]

14
8 When zinc reacts with hydrochloric acid, hydrogen gas is produced.

The graph shows how the volume of hydrogen gas produced changes with time when an excess of
zinc is reacted with 0.2 mol / dm3 hydrochloric acid.
80
60
volume of
hydrogen 40
gas / cm3
20
0
0 2 4 6 8 10 12
time / min
(a) Explain why the volume of hydrogen gas remains constant after six minutes.
............................................................................................................................................... [1]
(b) What volume of hydrogen gas was released in the first two minutes of the reaction?
............................................................................................................................................... [1]
(c) The experiment is repeated using the same volume of 0.1 mol / dm3 hydrochloric acid.
All other conditions are kept the same.
On the grid, draw the graph for the experiment using 0.1 mol / dm3 hydrochloric acid.
[2]
(d) Give the name of the salt formed when zinc reacts with hydrochloric acid.
............................................................................................................................................... [1]
(e) Which one of the following pH values could be the pH of dilute hydrochloric acid?
pH 1 pH 7 pH 9 pH 13 [1]
[Total: 6]
© UCLES 2018 0620/31/M/J/18

15
BLANK PAGE
© UCLES 2018 0620/31/M/J/18

Group
© UCLES 2018
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/31/M/J/18
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/31
MARK SCHEME
Maximum Mark: 80
Published
Teachers.

PUBLISHED
Generic Marking Principles
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
• the specific content of the mark scheme or the generic level descriptors for the question
• the specific skills defined in the mark scheme or in the generic level descriptors for the question
• the standard of response required by a candidate as exemplified by the standardisation scripts.
Marks awarded are always whole marks (not half marks, or other fractions).
Marks must be awarded positively:
• marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
• marks are awarded when candidates clearly demonstrate what they know and can do
• marks are not deducted for errors
• marks are not deducted for omissions
• answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.

PUBLISHED
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.

PUBLISHED
1(a)(i) ammonia / NH3 1
1(a)(ii) sulfur dioxide / SO2 1
1(a)(iii) methane / CH4 1
1(a)(iv) carbon dioxide / CO2 1
1(a)(v) argon / Ar 1
1(b)(i) helium is inert / it is inert / helium is unreactive / hydrogen is flammable 1
1(b)(ii) (old) light bulbs / welding / to protect reactive metals from oxidation / lasers 1
1(c) (substance containing) two (or more) types of atom bonded / two (or more) types of atom joined / two (or more) types of 1
atoms chemically combined
1(d) pair of bonding electrons between each N and H 1
two unpaired electrons on N AND no extra electrons on the H 1
2(a)(i) 15.5(%) 1
2(a)(ii) hydrogen / H2 1
2(a)(iii) nitrogen AND oxygen 1
2(a)(iv) NO2 1
2(a)(v) the air / the atmosphere 1

PUBLISHED
2(b)(i) compound of carbon and hydrogen only / compound of hydrogen and carbon with no other elements 2
IF 2 marks not scored:

1 mark for it contains carbon and hydrogen only / compound of hydrogen and carbon / molecules containing carbon and
hydrogen
2(b)(ii) poisonous / toxic 1
2(b)(iii) 5 (CO2) 1
6 (H2O) 1
3(a)(i) One mark each for any 3 of: 3
• (limonene) particles go from liquid to vapour
• diffusion
• random movement of particles / particles move anywhere / particles move in all directions
• spreading out of particles / intermingling of particles / mixing of particles / particles collide / particles bounce off each

other / particles go all over
• (bulk) movement of particles from higher to lower concentration / movement of particles down concentration gradient
3(a)(ii) solid 1
– 80 ºC is below the melting point / it is below the melting point / it has not yet reached its melting point / melts above – 80 ºC 1
3(b)(i) (substance which) speeds up a reaction / substance which increases the rate of reaction 1
3(b)(ii) addition of oxygen (to a substance) / loss of electrons / increase in oxidation number 1

PUBLISHED
3(c)(i) C=C bond 1
3(c)(ii) orange / red-brown / brown 1
to colourless 1
4(a) nickel<iron<chromium<magnesium 2

1 mark if all reversed / one consecutive pair reversed
4(b) One mark each for any 3 of: 3
• iron has high melting point / boiling point / ORA for K
• iron has high density / ORA for K
• iron has catalytic activity / ORA for K
• iron forms coloured compounds / ORA for K
• iron compounds have variable oxidation states / form ions with different charges / ORA for K
• iron is hard / potassium is soft / iron is strong / potassium is weak
• one suitable difference in chemical properties e.g. iron is less reactive than potassium ORA / potassium reacts with
cold water / iron does not react with cold water / iron rusts / potassium does not rust
• iron is magnetic / ORA for K

PUBLISHED
4(c) 3 (Fe) 1
2 (O2) 1
4(d) it loses oxygen / oxygen is removed from the iron oxide / hydrogen gains the oxygen from the iron oxide 1
4(e)(i) add (aqueous) sodium hydroxide / (aqueous) ammonia AND

green precipitate (2) 2

1 mark for add (aqueous) sodium hydroxide / (aqueous) ammonia
4(e)(ii) Fe2Cl 6 1
4(f) B / boiled water 1

AND
because no air / no oxygen
C / with calcium chloride 1

AND
because no water
5(a) breakdown 1
compound 1
molten 1
electricity 1
5(b) + electrode labelled anode and – electrode labelled cathode 1
liquid labelled electrolyte 1

PUBLISHED
5(c) graphite / it conducts electricity 1
5(d) negative electrode: zinc / Zn 1
positive electrode: iodine / I2 1
5(e) iodine 1
chlorine is more reactive than iodine ORA 1
6(a) One mark each for any 5 of: 5
• protons in the nucleus / centre (of the atom)
• neutrons in the nucleus / centre (of the atom)
• electrons outside the nucleus / electrons surrounding the nucleus / electrons orbiting the nucleus
• 9 protons
• 9 electrons
• 10 neutrons
6(b) element 1
atomic 1
nucleons 1
6(c) any suitable e.g. treating cancer / checking thyroid function / tracer (in the body) 1

PUBLISHED
6(d) 235 1
U
92
7(a)(i) atomic radius of Rb: any value between 228 and 264 (inclusive of these values) 1
relative thermal conductivity of K: any value between 3.8 and 1.7 (inclusive of these values) 1
7(a)(ii) decreases down (the Group) / increases up (the Group) / decreases from sodium to caesium ORA 1
7(a)(iii) bursts into flame / extremely rapid bubbling / explodes 1
7(b) second box down ticked (a sodium atom loses an electron) 1
7(c) basic oxide because metallic oxides are basic 1
7(d) 76 2

1 mark for (C =) 12, (H =) 1 (Na =) 23
7(e) sodium sulfate 1
water 1
8(a) the reaction is complete / the reaction has finished 1
8(b) any value between and including 37 (cm3) to 38 (cm3) 1

PUBLISHED
8(c) line starts from 0 cm3 AND initial gradient less steep 1
final volume levels off between 24–30 cm3 1

OR
line below 27 cm3 AND gradient becoming less steep at a later point
8(d) zinc chloride 1
8(e) pH 1 1

*2711517754*
CHEMISTRY 0620/41
1 hour 15 minutes

IB18 06_0620_41/5RP
2
1 Substances can be classified as elements, compounds or mixtures.
(a) What is meant by the term compound ?
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) Mixtures can be separated by physical processes.
A sequence of physical processes can be used to separate common salt (sodium chloride)

from a mixture containing sand and common salt only.
Give the order and the correct scientific term for the physical processes used to separate the
common salt from the mixture.
1 .................................................................................................................................................
2 .................................................................................................................................................
3 .................................................................................................................................................
[4]
The boiling points of four different alcohols, A, B, C and D, are shown.
alcohol A B C D
boiling point / °C 56 78 122 160
(c) A
student suggested that the apparatus shown could be used to separate the mixture of
alcohols.
fractionating column X
mixture of
hot water alcohols
A, B, C and D
electric heater
© UCLES 2018 0620/41/M/J/18

3
(i) Apparatus X needs to have cold water flowing through it.
● Draw an arrow on the diagram to show where the cold water enters apparatus X.
● Name apparatus X.
. ............................................................................................................................................
[2]
(ii) Part of the fractionating column is missing. This means that the experiment will not work.
● Draw on the diagram the part of the fractionating column which is missing.
● xplain why the experiment will not work with this part of the fractionating column
E
missing.
. ............................................................................................................................................
. ............................................................................................................................................
[2]
(iii) Suggest why a Bunsen burner is not used to heat the flask.
. ...................................................................................................................................... [1]
(iv) A hot water bath cannot be used to separate alcohols C and D.
Explain why.
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
[Total: 13]

4
2 Flerovium, Fl, atomic number 114, was first made in research laboratories in 1998.
(a) F
lerovium was made by bombarding atoms of plutonium, Pu, atomic number 94, with atoms of
element Z.
●● The nucleus of one atom of plutonium combined with the nucleus of one atom of element Z.
●● his formed the nucleus of one atom of flerovium.
T
Suggest the identity of element Z.
.............................................................................................................................................. [1]
(b) In which period of the Periodic Table is flerovium?
.............................................................................................................................................. [1]
(c) Predict the number of outer shell electrons in an atom of flerovium.
.............................................................................................................................................. [1]
(d) T
wo isotopes of flerovium are 286Fl and 289Fl. The nuclei of both of these isotopes are unstable
and emit energy when they split up.
(i) State the term used to describe isotopes with unstable nuclei.
. ...................................................................................................................................... [1]
(ii) C
omplete the table to show the number of protons, neutrons and electrons in the atoms of
the isotopes shown.
isotope number of protons number of neutrons number of electrons

286
Fl
289
Fl
[2]
(e) O
nly a relatively small number of atoms of flerovium have been made in the laboratory and the
properties of flerovium have not yet been investigated.
It has been suggested that flerovium is a typical metal.
(i) Suggest two physical properties of flerovium.
1 . .........................................................................................................................................
2 . .........................................................................................................................................
[2]
(ii) Suggest one chemical property of flerovium oxide.
. ...................................................................................................................................... [1]
[Total: 9]
© UCLES 2018 0620/41/M/J/18

5
3 This question is about iron.
(a) T
hree of the raw materials added to a blast furnace used to extract iron from hematite are
coke, hematite and limestone.
Name one other raw material added to the blast furnace.
.............................................................................................................................................. [1]
(b) A series of reactions occurs in a blast furnace during the extraction of iron from hematite.
escribe these reactions.

D
Include:
●● one chemical equation for the reduction of hematite
●● one chemical equation for the formation of slag.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [5]
(c) The iron extracted from hematite using a blast furnace is impure.
Identify the main impurity in this iron and explain how it is removed in the steel‑making process.
main impurity ..............................................................................................................................
how it is removed .......................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
[3]
[Total: 9]

6
4 This question is about masses, volumes and moles.
(a) Which term is defined by the following statement?
The average mass of naturally occurring atoms of an element

on a scale where the 12C atom has a mass of exactly 12 units.
.............................................................................................................................................. [1]
(b) B utane, C4H10, has a relative molecular mass of 58.

Potassium fluoride, KF, has a relative formula mass of 58.
xplain why the term relative molecular mass can be used for butane but cannot be used for
E
potassium fluoride.
....................................................................................................................................................
.............................................................................................................................................. [2]
(c) A 0.095 g sample of gaseous element Y occupies 60.0 cm3 at room temperature and pressure.
●● Determine the number of moles of element Y in 60.0 cm3.
moles of element Y = ............................. mol
●● Calculate the relative molecular mass of element Y and hence suggest the identity of
element Y.
relative molecular mass = .............................
identity of element Y = .............................

[3]
© UCLES 2018 0620/41/M/J/18

7
(d) A 1.68 g sample of phosphorus was burned and formed 3.87 g of an oxide of phosphorus.
Calculate the empirical formula of this oxide of phosphorus.
empirical formula = ............................. [4]
(e) A nother oxide of phosphorus has the empirical formula P2O3.

One molecule of this oxide of phosphorus contains four atoms of phosphorus.
Calculate the mass of one mole of this oxide of phosphorus.
mass = ............................. g [2]
[Total: 12]

8
5 (a) T
he table gives some chemical properties of transition elements and their compounds, and of
Group I elements and their compounds.
chemical property transition elements Group I elements

ability to act as catalysts yes no
exist as coloured compounds yes no
(i) What is meant by the term catalyst?
. ............................................................................................................................................
. ............................................................................................................................................
. ...................................................................................................................................... [2]
(ii) Give one other chemical property shown by transition elements which is not shown by
Group I elements.
. ...................................................................................................................................... [1]
(b) Give two physical properties shown by transition elements which are not shown by Group I
elements.
1 .................................................................................................................................................
2 .................................................................................................................................................
[2]
(c) T
he energy level diagram shows the energy profile for the reaction between zinc and dilute
sulfuric acid.
energy Zn(s) + H2SO4(aq)
progress of reaction
(i) Complete the diagram by adding the formulae of the products. Include state symbols. [3]
(ii) Draw an arrow on the diagram to represent the activation energy. [1]
(iii) Is the reaction endothermic or exothermic? Explain your answer.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
© UCLES 2018 0620/41/M/J/18

9
(d) T
he reaction between zinc and dilute sulfuric acid can be catalysed by the addition of aqueous
copper(II) sulfate.
On the diagram, add the energy profile for the catalysed reaction.
energy Zn(s) + H2SO4(aq)
[1]
(e) A student electrolyses aqueous copper(II) sulfate using the apparatus shown.
power supply
+ –
carbon electrodes
aqueous
copper(II) sulfate
Oxygen gas forms at the positive electrode (anode).
(i) W
rite an ionic half‑equation for the reaction at the negative electrode (cathode). Include
state symbols.
. ...................................................................................................................................... [3]
(ii) Describe what the student observes at the negative electrode.
. ...................................................................................................................................... [1]
(iii) Give two other observations which the student makes during the electrolysis.
1 . .........................................................................................................................................
2 . .........................................................................................................................................
[2]
(iv) W
hat difference would the student observe at the positive electrode if the aqueous
copper(II) sulfate were replaced by concentrated aqueous copper(II) chloride?
. ...................................................................................................................................... [1]
[Total: 18]

10
6 The table shows the structures of four hydrocarbons.
P Q R S
CH3–CH3 CH2=CH2 CH2=CH–CH3 CH2=CH–CH2–CH3
(a) Why are compounds P, Q, R and S known as hydrocarbons?
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) Compound P is saturated.
What is meant by the term saturated ?
....................................................................................................................................................
.............................................................................................................................................. [1]
(c) Compound P undergoes a substitution reaction with chlorine.
(i) What is meant by the term substitution reaction?
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(ii) State a condition required for this reaction to occur.
. ...................................................................................................................................... [1]
(iii) Write a chemical equation for this reaction.
. ...................................................................................................................................... [2]
(d) Compound R undergoes an addition reaction with bromine.
(i) Why is this reaction an addition reaction?
. ...................................................................................................................................... [1]
(ii) A compound containing bromine is formed in this reaction.
Draw the structure of this compound. Show all of the atoms and all of the bonds.
[1]
© UCLES 2018 0620/41/M/J/18

11
(e) D
raw the structure of an unbranched isomer of compound S. Show all of the atoms and all of
the bonds. Name this unbranched isomer of compound S.
structure
name ..........................................................................................................................................
[2]
(f) Compound Q undergoes polymerisation.
(i) Name the polymer formed.
. ...................................................................................................................................... [1]
(ii) Complete the chemical equation to show the polymerisation of compound Q.
n CH2=CH2
[2]
(g) A
mino acids undergo polymerisation to form proteins. Part of a protein molecule with the
linkages missing is shown.
Draw the linkages on the diagram. Show all of the atoms and all of the bonds.
H O
N C
[2]
(h) The structure shows an ester.
CH3 CH2 CH2 C
O CH2 CH3
Write the word equation for a reaction which could be used to make this ester.
.............................................................................................................................................. [3]
[Total: 19]
© UCLES 2018 0620/41/M/J/18

Group
© UCLES 2018
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
12
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/41/M/J/18
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/41
MARK SCHEME
Maximum Mark: 80
Published
Teachers.

PUBLISHED
marking principles.
descriptors.

PUBLISHED

PUBLISHED
1(a) a substance made from two (or more) elements 1
chemically combined 1
1(b) dissolving 1
filtration 1
evaporation / crystallisation 1
three correct stages in the correct order 1
1(c)(i) condenser 1
arrow pointing into lower aperture only 1
1(c)(ii) stopper shown in diagram 1
gases or vapours escape 1
1(c)(iii) (mixture is) (in)flammable 1
1(c)(iv) water bath cannot exceed 100 (°C) 1
C AND D have a boiling point above 100 (°C) 1

PUBLISHED
2(a) calcium / Ca 1
2(b) 7 1
2(c) 4 1
2(d)(i) radioisotopes 1
286
2(d)(ii) Fl 114p 172n 114e 1
289
Fl 114p 175n 114e 1
2(e)(i) any two from: 2
high melting point / boiling point

hard
dense
conduct electricity
conduct heat
ductile / malleable
sonorous
lustrous / shiny
2(e)(ii) basic (oxide) 1

PUBLISHED
3(a) (hot) air 1
3(b) coke is burned (to form carbon dioxide) 1

OR
C + O2 → CO2
carbon dioxide is reduced by (more) coke to form carbon monoxide or CO 1

OR
C + CO2 → 2CO
3CO + Fe2O3 → 2Fe + 3CO2 1
limestone (decomposes to) form lime / CaO / calcium oxide (and carbon dioxide) 1

OR
CaCO3 → CaO + CO2
CaO + SiO2 → CaSiO3 1
3(c) the impurity is C 1
blow into or pass oxygen through (molten) iron 1
carbon dioxide escapes or carbon dioxide is a gas 1

PUBLISHED
4(a) relative atomic mass 1
4(b) C4H10 is covalent 1
KF is ionic 1
4(c) mol of Y = 0.060 / 24.0 = 2.5 × 10–3 or 0.0025 1
Mr = 0.095 / 2.5 × 10–3 = 38(.0) 1
fluorine 1
4(d) mass of O = 3.87 g – 1.68 g = 2.19 (g) 1
mol of P and mol of O 1

1.68 / 31 OR 0.054.. 2.19 / 16 OR 0.13
ratio of P to O 1
P = 0.054 / 0.054 O = 0.13 / 0.054
=1 = 2.5
whole number ratio and P2O5 1

=2 =5
4(e) the formula is P4O6 or (one mole of) P2O3 = 110 (g) 1
mass = 220 (g) 1

PUBLISHED
5(a)(i) (a substance which) increases the rate of a reaction 1
without being used up (at the end) / remains unchanged or unaffected or without changing mass 1
5(a)(ii) variable oxidation states 1
high(er) melting point / boiling point

(very) hard(er)
(very) strong(er)
dense(r)
5(c)(i) ZnSO4 1
H2 written on product line 1
states (aq) AND (g) 1
5(c)(ii) (labelled) arrow pointing upwards starting level with reactants and finishing level with top of the hump. 1
5(c)(iii) exothermic AND products are at lower energy (than reactants) 1
5(d) lower hump starting from reactants line 1
5(e)(i) Cu2+(aq) + 2e– → Cu(s) 3
1 mark for any equation which has Cu as the product or Cu2+ ions on left
1 mark for correct species
1 mark for correct state symbols
5(e)(ii) (a pink / brown) solid / deposit forms 1
5(e)(iii) bubbles / fizzing (at the anode) 1
solution becomes paler / less blue / colourless 1

PUBLISHED
5(e)(iv) a green gas would be seen (on the anode) 1
6(a) (they contain) carbon and hydrogen (atoms) 1
only 1
6(b) (all) the (C–C) bonds are single 1
6(c)(i) (one) atom or group is replaced by another (atom or group) 1
6(c)(ii) ultra-violet light OR sunlight 1
6(c)(iii) C2H6 + Cl2 → C2H5Cl + HCl 2
1 mark for C2H5Cl

1 mark for the rest of the equation
6(d)(i) only one product (compound) forms 1
6(d)(ii) fully displayed formula of 1,2-dibromopropane 1
6(e) fully displayed formula of but-2-ene 1
but-2-ene 1

PUBLISHED
6(f)(i) poly(ethene) 1
6(f)(ii) single bond between two C atoms 1
fully correct answer 1
6(g) any one correct amide link showing all bonds 1
both amide links shown in the correct orientation for three amino acids 1
6(h) ethanol + butanoic acid → ethyl butanoate + water 3
1 mark for the names of the reactants

1 mark for the name of the ester
1 mark for water as a product

CHEMISTRY 0620/51
INSERT
1 hour 15 minutes
*8393780945-I*
CAMBRIDGE INTERNATIONAL EXAMINATIONS CAMBRIDGE INTERNATIONAL EXAMINATIONS CAMBRIDGE INTERNATIONAL EXAMINATIONS CAMBRIDGE
INTERNATIONAL EXAMINATIONS CAMBRIDGE INTERNATIONAL EXAMINATIONS CAMBRIDGE INTERNATIONAL EXAMINATIONS CAMBRIDGE INTERNATIONAL
EXAMINATIONS CAMBRIDGE INTERNATIONAL EXAMINATIONS CAMBRIDGE INTERNATIONAL EXAMINATIONS CAMBRIDGE INTERNATIONAL EXAMINATIONS
This document consists of 1 printed page and 1 blank page.
IB18 06_0620_51/RP
2
BLANK PAGE
© UCLES 2018 0620/51/INSERT/M/J/18

*8393780945*
CHEMISTRY 0620/51


1 hour 15 minutes

Total
This document consists of 11 printed pages, 1 blank page and 1 Insert.
IB18 06_0620_51/3RP
2
BLANK PAGE
© UCLES 2018 0620/51/M/J/18

3
1 You are going to investigate the rate of reaction between dilute hydrochloric acid and aqueous

Instructions
You are going to do five experiments using the apparatus shown.
eye
printed insert
printed words

Experiment 1
● se the large measuring cylinder to pour 50 cm3 of aqueous sodium thiosulfate into the conical
U
flask. Place the conical flask on the printed insert.
● Fill the small measuring cylinder with 10 cm3 of dilute hydrochloric acid.
● Add the dilute hydrochloric acid to the solution in the conical flask. Start the timer immediately
and swirl the mixture.
● View the conical flask from above and measure the time taken for the printed words to disappear
from view. Record the time taken in the table on page 4.
● Immediately pour the contents of the conical flask into the quenching bath and rinse the conical
flask with distilled water.

Experiment 2
● se the large measuring cylinder to pour 40 cm3 of aqueous sodium thiosulfate into the conical
U
flask, followed by 10 cm3 of distilled water. Place the conical flask on the printed insert.
● Fill the small measuring cylinder with 10 cm3 of dilute hydrochloric acid.
● Add the dilute hydrochloric acid to the solution in the conical flask. Start the timer immediately
and swirl the mixture.
● View the conical flask from above and measure the time taken for the printed words to disappear
from view. Record the time taken in the table on page 4.
● Immediately pour the contents of the conical flask into the quenching bath and rinse the conical
flask with distilled water.

4
Experiment 3
● epeat Experiment 2 but use 35 cm3 of aqueous sodium thiosulfate, 15 cm3 of distilled water
R
and 10 cm3 of dilute hydrochloric acid.

Experiment 4

R

Experiment 5

R
(a) Complete the table.
time taken for the

volume of aqueous volume of
experiment printed words to
sodium thiosulfate / cm3 distilled water / cm3
disappear from view / s
[3]
© UCLES 2018 0620/51/M/J/18

5
(b) Plot your results from Experiments 1–5 on the grid. Draw a smooth line graph.
350
300
250
200
time taken for the
printed words to
disappear from view / s
150
100
50
0
0 10 20 30 40 50
volume of aqueous sodium thiosulfate / cm 3
[3]
(c) Describe the appearance of the mixture in the conical flask at the end of each experiment.
............................................................................................................................................... [1]
(d) (i)
From your graph, deduce the time taken for the printed words to disappear from view
if Experiment 2 were repeated using 20 cm3 of aqueous sodium thiosulfate and 30 cm3 of
distilled water.
.............................. s [2]

6
(ii) The rate of reaction can be calculated using the equation shown.
1
rate of reaction =
time taken
Calculate the rate of reaction using your answer from (d)(i).
........................................................................................................................................ [1]
(e) (i) In which experiment, 1, 2, 3, 4 or 5, was the rate of reaction greatest?
........................................................................................................................................ [1]
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(f) Give the name of a more accurate piece of apparatus for measuring volumes than a measuring
cylinder.
............................................................................................................................................... [1]
(g) S
uggest the effect on the results of using a 100 cm3 conical flask instead of a 250 cm3
conical flask. Explain your answer.
.....................................................................................................................................................
............................................................................................................................................... [2]
(h) S
ketch on the grid the graph you would expect if all of the experiments were repeated at a
lower temperature. Clearly label your graph. [1]
[Total: 17]
© UCLES 2018 0620/51/M/J/18

7
2 ou are provided with two substances, solution A and solid B.

Y
Do the following tests on the substances, recording all of your observations at each stage.
tests on solution A

Divide solution A into four approximately equal portions in three test-tubes and one boiling tube.
(a) Test the pH of the first portion of solution A.
pH = .............................. [1]
(b) A
dd a strip of magnesium ribbon to the second portion of solution A in a test‑tube. Shake the
mixture.
.....................................................................................................................................................
............................................................................................................................................... [1]
dd a spatula measure of copper(II) oxide to the third portion of solution A in a boiling tube.

(c) A
Warm the mixture gently.
............................................................................................................................................... [1]
Keep the fourth portion of solution A for the test in (e).


8
tests on solid B
(d) U
se a spatula to place approximately half of solid B into a hard glass test-tube. Heat solid B
gently then strongly. Leave the hard glass test-tube to stand for approximately 1 minute.
............................................................................................................................................... [2]
(e) Add the rest of solid B to the fourth portion of solution A in a test-tube. Test the gas produced.
test ..............................................................................................................................................
result ...........................................................................................................................................
[2]
Keep the solution from the test in (e) for the test in (f).

dd an approximately equal volume of distilled water to the solution from the test in (e). Shake the
A
solution and divide it into three approximately equal portions in two test-tubes and one boiling tube.
(f) (i) A
dd a few drops of aqueous sodium hydroxide to the first portion of the solution in a
test‑tube.
........................................................................................................................................ [1]
(ii) Now add an excess of aqueous sodium hydroxide to the mixture.

........................................................................................................................................ [1]
(g) (i) Add a few drops of aqueous ammonia to the second portion of the solution in a test‑tube.
........................................................................................................................................ [1]
(ii)
Now add an excess of aqueous ammonia to the mixture.
........................................................................................................................................ [1]
(h) A
dd a small piece of aluminium foil and about 2 cm3 of aqueous sodium hydroxide to the third
portion of the solution in a boiling tube. Gently warm the mixture. Test the gas produced with
indicator paper.
............................................................................................................................................... [2]
© UCLES 2018 0620/51/M/J/18

9
(i) Identify solution A.
............................................................................................................................................... [2]
(j) Identify solid B.
............................................................................................................................................... [2]
[Total: 17]

10
3 otassium chloride is a salt that dissolves in water.

P
The solubility of a salt is the mass in grams of the salt that dissolves in 100 cm3 of water at a
particular temperature.
Plan an investigation to determine the solubility of potassium chloride in water at 40 °C.
You are provided with potassium chloride and common laboratory apparatus.
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
...................................................................................................................................................... [6]
[Total: 6]
© UCLES 2018 0620/51/M/J/18

11

Tests for anions

produced

sulfate (SO42–) acidify, then add aqueous white ppt.

[in solution] barium nitrate
sulfite (SO32–) add dilute hydrochloric acid, warm sulfur dioxide produced
gently and test for the presence of will turn acidified aqueous
sulfur dioxide potassium manganate(VII) from
colourless solution
© UCLES 2018 0620/51/M/J/18

12
ammonia (NH3) turns damp red litmus paper blue lithium (Li+) red

© UCLES 2018 0620/51/M/J/18

CHEMISTRY 0620/51
MARK SCHEME
Maximum Mark: 40
Published
Teachers.

PUBLISHED
marking principles.
descriptors.

PUBLISHED

PUBLISHED
1(a) volumes of sodium thiosulfate, 50, 40, 35, 30, 10 AND 1

volumes of water 0, 10, 15, 20, 40 completed correctly
times completed in seconds 1
comparable to supervisor’s 1
1(b) all points plotted correctly (± half a small square) 2
smooth line graph 1
1(c) pale yellow (precipitate) / cloudy 1
1(d)(i) value from graph 1
indication 1
1(d)(ii) 1 ÷ time in (d)(i) 1
1(e)(i) experiment 1 1
1(e)(ii) more particles of thiosulfate present (in a given volume) 1
more (chance of) collisions 1
1(f) pipette / burette 1
1(g) times would be shorter 1
idea of depth of solution 1
1(h) sketch above original curve 1

PUBLISHED
2(a) pH 1–3 1
2(b) effervescence / fizz / bubbles / magnesium disappears 1
2(c) turns blue 1
2(d) turns yellow 1
white on standing 1
2(e) limewater 1
milky / cloudy / white ppt. 1
2(f)(i) white precipitate 1
2(f)(ii) clears / dissolves / colourless / soluble 1
2(g)(i) white precipitate 1
2(g)(ii) clears / dissolves / colourless / soluble 1
2(h) bubbles / fizz / effervescence 1
pH>7 / indicator paper turns blue 1
2(i) nitric 1
acid 1
2(j) zinc 1
carbonate 1

PUBLISHED
3 any 6 from one method: max 6
evaporation
• measured volume of water
• using measuring cylinder / pipette / burette
• heat to 40 °C / heat to >40 °C
• add KCl until no more dissolves / add excess KCl
• stir
• filter mixture (if heated to >40 °C then need to cool and filter)
• evaporate filtrate to dryness
• weigh solid
mass not used

• heat to 40 °C
• add KCl until no more dissolves
• stir
• weigh KCl not added
• weigh KCl before adding any to water – only awarded if weighed mass not used after
• difference in mass of KCl is mass dissolved
mass undissolved
• heat to 40 °C
• stir
• filter
• weigh residue (do not award if residue washed)
• add weighed (excess) KCl to water – only awarded if mass of residue measured
• mass KCl dissolved = initial mass – final mass

*3983955427*
CHEMISTRY 0620/61
1 hour

IB18 06_0620_61/3RP
2
1 The volume of dilute nitric acid that reacts with 25.0 cm3 of aqueous potassium hydroxide can be
found by titration using the apparatus shown.
...........................................
dilute nitric acid
25.0 cm3 of aqueous

potassium hydroxide
with indicator
(b) Name a suitable indicator that could be used.
............................................................................................................................................... [1]
A student did the titration four times and recorded the following results.
titration number volume of dilute nitric acid / cm3

1 18.1
2 18.9
3 18.3
4 18.2
(c) (i) Which one of the results is anomalous?
........................................................................................................................................ [1]
(ii) Suggest what might have caused this result to be anomalous.
........................................................................................................................................ [1]
(iii) Use the other results to calculate the average volume of dilute nitric acid that reacted with
the aqueous potassium hydroxide.
........................................................................................................................................ [2]
© UCLES 2018 0620/61/M/J/18

3
(d) The equation for the reaction taking place in the titration is shown.
HNO3 + KOH KNO3 + H2O
The student concluded that the aqueous potassium hydroxide was more concentrated than the
dilute nitric acid.
Explain whether or not the student’s conclusion was correct.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
[Total: 8]

4
2
A student investigated the rate of reaction between dilute hydrochloric acid and aqueous
Five experiments were done using the apparatus shown.
eye
printed sheet of paper

printed words
© UCLES 2018 0620/61/M/J/18

5
Experiment 1
● large measuring cylinder was used to pour 50 cm3 of aqueous sodium thiosulfate into a
A
250 cm3 conical flask. The conical flask was placed on a printed sheet of paper.
● 10 cm3 of dilute hydrochloric acid was added to the solution in the conical flask. A timer was
started immediately and the mixture was swirled.

Experiment 2
● he large measuring cylinder was used to pour 40 cm3 of aqueous sodium thiosulfate into a
T
conical flask, followed by 10 cm3 of distilled water. The conical flask was placed on the printed
sheet of paper.
● 10 cm3 of dilute hydrochloric acid was added to the solution in the conical flask. The timer was
started immediately and the mixture was swirled.

Experiment 3
● xperiment 2 was repeated but using 35 cm3 of aqueous sodium thiosulfate and 15 cm3 of
E
distilled water.

Experiment 4
E
distilled water.

Experiment 5
E
distilled water.

6
(a) Record the volumes of distilled water used in the table. Use the stop-clock diagrams to record
the results in the table.
time taken for

volume of volume of
the printed words
experiment aqueous sodium distilled water stop-clock diagram
to disappear
thiosulfate / cm3 / cm3
from view / s
0
seconds
0
1 50 45 15 5 15
10
minutes
30
0
0
2 40 45 15 5 15
10
30
0
0
3 35 45 15 5 15
10
30
0
0
4 30 45 15 5 15
10
30
0
0
5 10 45 15 5 15
10
30
[3]
© UCLES 2018 0620/61/M/J/18

7
(b) Plot the results from Experiments 1–5 on the grid. Draw a smooth line graph.
240
210
180
150
time taken for
the printed words
to disappear
from view / s 120
90
60
30
0
0 10 20 30 40 50
volume of aqueous sodium thiosulfate / cm3
[3]
(c) (i)
From your graph, deduce the time taken for the printed words to disappear from view
if Experiment 2 were repeated using 20 cm3 of aqueous sodium thiosulfate and 30 cm3 of
distilled water.
.............................. s [2]

8
(ii) The rate of reaction can be calculated using the equation shown.
1
rate of reaction =
time taken
Calculate the rate of reaction using your answer from (c)(i).
........................................................................................................................................ [1]
(d) (i) In which experiment, 1, 2, 3, 4 or 5, was the rate of reaction greatest?
........................................................................................................................................ [1]
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(e) Give the name of a more accurate piece of apparatus for measuring volumes than a measuring
cylinder.
............................................................................................................................................... [1]
(f) Suggest the effect on the results of using a 100 cm3 conical flask instead of a 250 cm3 conical
flask. Explain your answer.
.....................................................................................................................................................
............................................................................................................................................... [2]
(g) Sketch on the grid the graph you would expect if all of the experiments were repeated at a
lower temperature. Clearly label your graph. [1]
[Total: 16]
© UCLES 2018 0620/61/M/J/18

9
3 Two substances, solution A and solid B, were analysed.
tests on solution A
Some of the tests and observations are shown.
tests on solution A observations
Solution A was divided into three equal portions

in three test-tubes.
test 1
The pH of the first portion of solution A was pH = 1

tested.
test 2
Magnesium ribbon was added to the second effervescence

portion of solution A.
The gas produced was tested. gas ‘popped’ with a lighted splint
test 3
Dilute nitric acid and aqueous barium nitrate white precipitate formed
were added to the third portion of solution A.
(a) Identify the gas produced in test 2.
............................................................................................................................................... [1]
(b) Identify solution A.
............................................................................................................................................... [2]

10
tests on solid B
Solid B was zinc carbonate.
(c) Dilute nitric acid was added to solid B. The gas produced was tested.
observations ...............................................................................................................................
............................................................................................................................................... [2]
The zinc nitrate solution formed in the test in (c) was divided into two portions in two test‑tubes.
(d) (i) D
rops of aqueous sodium hydroxide were added to the first portion of the zinc nitrate
solution.
observations .................................................................................................................. [2]
(ii)
An excess of aqueous sodium hydroxide was then added to the mixture.
observations .................................................................................................................. [1]
(e) (i)
Drops of aqueous ammonia were added to the second portion of the zinc nitrate solution.
observations .................................................................................................................. [1]
(ii) An excess of aqueous ammonia was then added to the mixture.
observations .................................................................................................................. [1]
[Total: 10]
© UCLES 2018 0620/61/M/J/18

11
4 Potassium chloride is a salt that dissolves in water.

The solubility of a salt is the mass in grams of the salt that dissolves in 100 cm3 of water at a
particular temperature.
Plan an investigation to determine the solubility of potassium chloride in water at 40 °C.
You are provided with potassium chloride and common laboratory apparatus.
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
...................................................................................................................................................... [6]
[Total: 6]

12
BLANK PAGE
© UCLES 2018 0620/61/M/J/18

CHEMISTRY 0620/61
MARK SCHEME
Maximum Mark: 40
Published
Teachers.

PUBLISHED
marking principles.
descriptors.

PUBLISHED

PUBLISHED
1(a) burette 1
1(b) methyl orange / thymolphthalein / litmus 1
1(c)(i) number 2 / 18.9 cm3 1
1(c)(ii) overshot end point / more than 25 cm3 KOH in flask 1
1(c)(iii) 18.2 1
cm3 1
1(d) (wrong conclusion) nitric acid more concentrated / stronger 1
smaller volume of acid needed 1
2(a) volume boxes completed correctly in seconds 1

0, 10, 15, 20, 40
time boxes completed correctly 2

27, 33, 45, 66, 201
2(b) all points plotted correctly (± half a small square) 2
smooth line graph 1
2(c)(i) value from graph 1
with clear indication 1
2(c)(ii) 1 ÷ value from (c)(i) 1
2(d)(i) experiment 1 1

PUBLISHED
2(d)(ii) more particles of thiosulfate (in a given volume) 1
more chance of collision 1
2(e) use a pipette / burette 1
2(f) times would be shorter 1
idea of depth of solution is greater 1
2(g) sketch curve roughly same shape and above original 1
3(a) hydrogen / H2 1
3(b) sulfuric 1
acid 1
3(c) limewater 1
milky / cloudy / white ppt. 1
3(d)(i) white 1
precipitate 1
3(d)(ii) dissolves / clears / goes colourless 1
3(e)(i) white precipitate 1
3(e)(ii) dissolves / clears / goes colourless 1

PUBLISHED
4 any 6 from one method: max 6
evaporation
• heat to 40 °C / heat to >40 °C
• add KCl until no more dissolves / add excess KCl
• stir
• filter mixture (if heated to >40 °C then need to cool and filter)
• evaporate filtrate to dryness
• weigh solid
mass not used

• heat to 40 °C
• add KCl until no more dissolves
• stir
• weigh KCl not added
• weigh KCl before adding any to water – only awarded if weighed mass not used after
• difference in mass of KCl is mass dissolved
mass undissolved
• heat to 40 °C
• stir
• filter
• weigh residue (do not award if residue washed)
• add weighed (excess) KCl to water – only awarded if mass of residue measured
• mass KCl dissolved = initial mass – final mass

CHEMISTRY 0620/11
45 minutes
Soft clean eraser
*7680430453*

Write your name, centre number and candidate number on the Answer Sheet in the spaces provided unless
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level1/Level 2 Certificate.
IB19 06_0620_11/3RP
2
1 Sodium chloride is a liquid at 900 °C.
How are the particles arranged and how do the particles move in sodium chloride at 900 °C?
arrangement of particles motion of particles
A regular vibrate about a fixed point

B regular move randomly
C random vibrate about a fixed point
D random move randomly
2 2.00 g of powdered calcium carbonate is added to 50.0 cm3 of hydrochloric acid.
Which apparatus is used to measure the calcium carbonate and the hydrochloric acid?
calcium carbonate hydrochloric acid
A balance burette
B balance thermometer
C pipette burette
D pipette thermometer
3 Rock salt is a mixture of sand and sodium chloride.
Sodium chloride is soluble in water but not in hexane.
Sand is insoluble in both water and hexane.
What is required to separate the sand from the sodium chloride?
1 filter paper
2 fractionating column
3 hexane
4 water
© UCLES 2019 0620/11/M/J/19

3
4 The colours in four dyes are separated using chromatography.
Which chromatogram shows an insoluble colour?
A B C D
baseline
19
5 Which statement about an atom of fluorine, 9 F, is correct?
A It contains more protons than neutrons.

B It contains a total of 28 protons, neutrons and electrons.
C Its isotopes contain different numbers of protons.
D Its nucleus contains 9 neutrons.
6 Calcium reacts with chlorine to produce calcium chloride.
What happens when a calcium ion forms during this reaction?
A The calcium atom gains one electron.

B The calcium atom gains two electrons.
C The calcium atom loses one electron.
D The calcium atom loses two electrons.
7 Which row describes the formation of single covalent bonds in methane?
A atoms share a pair of electrons both atoms gain a

noble gas electronic structure
B atoms share a pair of electrons both atoms have the same number
of electrons in their outer shell
C electrons are transferred from one both atoms gain a
atom to another noble gas electronic structure
D electrons are transferred from one both atoms have the same number
atom to another of electrons in their outer shell

4
8 Diamond and graphite have giant covalent structures of carbon atoms.
Which statement describes graphite?
A It has a strong, rigid three-dimensional structure.

B It has four strong covalent bonds between each carbon atom.
C It has layers, which can slide over each other.
D It has no free electrons, so does not conduct electricity.
9 The compound magnesium nitrate has the formula Mg(NO3)2.
What is the relative formula mass of magnesium nitrate?
A 86 B 134 C 148 D 172
10 Four substances are electrolysed using inert electrodes.
Which row describes the electrode products?
substance anode product cathode product
A concentrated aqueous sodium chloride hydrogen chlorine

B concentrated hydrochloric acid chlorine oxygen
C dilute sulfuric acid oxygen hydrogen
D molten lead bromide lead bromine
11 Dissolving ammonium chloride in water is an endothermic change.
Which row shows the energy change and temperature change of the mixture during the
dissolving of ammonium chloride?
energy change temperature change
A energy is absorbed decrease

B energy is absorbed increase
C energy is released decrease
D energy is released increase
12 Which process is a physical change?
A burning wood
B cooking an egg
C melting an ice cube
D rusting iron
© UCLES 2019 0620/11/M/J/19

5
13 Hydrogen peroxide solution decomposes very slowly at room temperature to produce oxygen
gas. This gas forms a rising foam when liquid detergent is added.
Five test-tubes are half filled with hydrogen peroxide solution. A drop of liquid detergent is added
to each one.
Different metal oxides are added to four of the test-tubes and the height of the foam formed after
1 minute is measured. The results are shown.
height of
metal oxide
foam / cm
no metal oxide added 0.1

aluminium oxide 0.1
calcium oxide 0.2
copper(II) oxide 2.3
manganese(IV) oxide 5.4
Which conclusion can be drawn from these results?
A Metal oxides do not affect the rate of this reaction.

B All metal oxides increase the rate of this reaction and act as catalysts.
C Manganese(IV) oxide is the best catalyst of the four metal oxides tested.
D Only transition element oxides increase the rate of this reaction.
14 When blue-green crystals of nickel(II) sulfate are heated, water is produced and a yellow solid
remains. When water is added to the yellow solid, the blue-green colour returns.
Which process describes these changes?
A combustion
B corrosion
C neutralisation
D reversible reaction

6
15 In a blast furnace, iron is extracted when iron(III) oxide reacts with carbon monoxide.
Fe2O3 + 3CO → 2Fe + 3CO2
Which substance is oxidised and which is reduced?
oxidised reduced
A CO Fe2O3
B CO2 Fe
C Fe CO2
D Fe2O3 CO
16 Four different solutions are separately tested with blue litmus and with methyl orange. Each
solution is known to be either acidic or alkaline. The results are shown.
result with result with

solution
blue litmus methyl orange
1 red red
2 red yellow
3 blue yellow
4 blue yellow
A Solutions 1 and 4 are acidic.

B Solutions 1 and 2 are alkaline.
C Solutions 3 and 4 are alkaline.
D Solutions 3 and 4 are acidic.
Y
X Z
© UCLES 2019 0620/11/M/J/19

7
18 How could crystals of a pure salt be prepared from dilute sulfuric acid?
A add an excess of aqueous sodium hydroxide, filter, evaporate the filtrate to crystallisation
point
B add an excess of copper(II) carbonate, filter, evaporate the filtrate to dryness
C add an excess of copper metal, filter, evaporate the filtrate to crystallisation point
D add an excess of zinc oxide, filter, evaporate the filtrate to crystallisation point
19 The results of two tests on a solution of compound Q are shown.
test observation
add ammonia solution green precipitate formed
add dilute nitric acid followed white precipitate formed
by aqueous barium nitrate
What is Q?
A iron(II) chloride
B iron(II) sulfate
C iron(III) chloride
D iron(III) sulfate
20 The properties of an element are shown.
electrical conductivity density reaction with water

high low reacts violently with cold water
Which element has these properties?
A B
C
D
21 Which statement about elements in Group I and Group VII of the Periodic Table is correct?
A Bromine reacts with potassium chloride to produce chlorine.

B Iodine is a monoatomic non-metal.
C Lithium has a higher melting point than potassium.
D Sodium is more reactive with water than potassium.

8
22 Which row describes the properties of a transition element?
melting forms coloured

density
point compounds
A high low no
B high high yes
C low low no
D low low yes
23 Which statement about elements in Group VIII of the Periodic Table is correct?
A They all have a full outer shell of electrons.

B They all react with Group I elements to form ionic compounds.
C They are all diatomic molecules.
D They are all liquids at room temperature.
24 The diagrams show the structure of two substances used to make electrical conductors.
X Y
Which statement correctly describes X and Y?
A X is a pure metal and Y is a compound.

B X is a pure metal and Y is an alloy.
C X is a solid and Y is a liquid.
D X is harder and stronger than Y.
© UCLES 2019 0620/11/M/J/19

9
25 The reactions of three metals, P, Q and R, are shown.
metal reacts with metal reacts

dilute hydrochloric acid with water
P yes no
Q no no
R yes yes
most least
reactive reactive
A P Q R
B Q R P
C R Q P
D R P Q
26 Iron is extracted from its ore in a blast furnace.
Hematite, coke, limestone and hot air are added to the furnace.
Which explanation is not correct?
A Coke burns and produces a high temperature.
B Hematite is the ore containing the iron as iron(III) oxide.
C Hot air provides the oxygen for the burning.
D Limestone reduces the iron(III) oxide to iron.
27 Why is aluminium used to make containers for storing food?
B It has a high melting point.
C It is resistant to corrosion.
D It is strong.

10
28 Water can be treated by filtration then chlorination.
Which uses do not need water of this quality?
1 water for cooling in industry

2 water for washing clothes
3 water for drinking
29 Four sources of air pollution are listed.
1 burning fossil fuels containing sulfur

2 nitrogen reacting with oxygen in car engines
3 incomplete combustion of carbon fuels
4 adding lead compounds to petrol
Which sources produce acid rain?
P Q
iron painted iron
air
water
tube P tube Q
A falls rises
B no change rises
C rises falls
D rises no change
© UCLES 2019 0620/11/M/J/19

11
31 A mixture of two substances, R and S, is heated.
The damp red litmus paper turns blue.
damp red
litmus paper
R and S
gentle heat
What are R and S?
R S
A a basic oxide ammonium chloride

B a basic oxide sodium nitrate
C an acidic oxide ammonium chloride
D an acidic oxide sodium nitrate
32 Which statement describes a disadvantage of sulfur dioxide?
A It can be used as a bleach when making wood pulp.

B It can be used to kill bacteria in food.
C It can be used to manufacture sulfuric acid.
D It dissolves in water to form acid rain.

12
33 The diagram represents a lime kiln used to heat limestone to a very high temperature.
waste gases
lime kiln
limestone
fuel in fuel in
air in air in
What leaves the kiln at X?
A calcium carbonate
B calcium hydroxide
C calcium oxide
D calcium sulfate
34 What is the structure of ethanol?
A B C D
H H H H H O H H
C C H C C H H C C H C C OH
H H H H H OH H H
© UCLES 2019 0620/11/M/J/19

13
35 Which fuel could be gasoline?
Is it obtained
from petroleum?
yes no
Is it used as Is it used as
fuel for cars? fuel for cars?
yes no yes no
A B C D
36 A hydrocarbon W burns to form carbon dioxide and water.
W decolourises bromine water.
What is the name of W and what is its structure?
name of W structure of W
H H
A ethane H C C H
H H
H H
B ethane C C
H H
H H
C ethene H C C H
H H
H H
D ethene C C
H H

14
37 Why is ethanol a member of the homologous series of alcohols but propane is not?
A Ethanol has two carbon atoms per molecule but propane has three.
B Ethanol can be made from ethene but propane is obtained from petroleum.
C Ethanol is a liquid but propane is a gas.
D Ethanol contains the same functional group as other alcohols but propane does not.
38 Which statements about ethanol are correct?
1 It can be made by fermentation.

2 It is an unsaturated compound.
3 It burns in air and can be used as a fuel.
39 Which statements about aqueous ethanoic acid are correct?
1 Ethanoic acid contains the functional group –COOH.

2 Ethanoic acid reacts with carbonates to produce hydrogen.
3 Ethanoic acid turns Universal Indicator paper blue.
4 Ethanoic acid has a pH lower than pH 7.
40 Which naturally occurring polymers are found in foods?
1 complex carbohydrates
2 nylon
3 salts
4 proteins
© UCLES 2019 0620/11/M/J/19

15
BLANK PAGE
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2019 0620/11/M/J/19

Group
© UCLES 2019
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
16
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/11/M/J/19
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/11
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.

PUBLISHED
1 D 1
2 A 1
3 B 1
4 D 1
5 B 1
6 D 1
7 A 1
8 C 1
9 C 1
10 C 1
11 A 1
12 C 1
13 C 1
14 D 1
15 A 1
16 C 1
17 A 1
18 D 1
19 B 1
20 D 1
21 C 1
22 B 1
23 A 1
24 B 1
25 D 1
26 D 1
27 C 1
28 B 1

PUBLISHED
29 A 1
30 D 1
31 A 1
32 D 1
33 C 1
34 D 1
35 A 1
36 D 1
37 D 1
38 C 1
39 C 1
40 B 1

CHEMISTRY 0620/21
45 minutes
Soft clean eraser
*7311411163*

IB19 06_0620_21/3RP
2
1 Which statement explains why ammonia gas, NH3, diffuses at a faster rate than
hydrogen chloride gas, HCl ?
A Ammonia expands to occupy all of the space available.

B Ammonia has a smaller relative molecular mass than hydrogen chloride.
C Ammonia is an alkali and hydrogen chloride is an acid.
D Ammonia molecules diffuse in all directions at the same time.
2 2.00 g of powdered calcium carbonate is added to 50.0 cm3 of hydrochloric acid.
Which apparatus is used to measure the calcium carbonate and the hydrochloric acid?
calcium carbonate hydrochloric acid
A balance burette
B balance thermometer
C pipette burette
D pipette thermometer
3 The measurements from a chromatography experiment using substance F are shown. The
diagram is not drawn to scale.
solvent front
distance moved by F
100 mm
90 mm
55 mm
15 mm
baseline
What is the Rf value of F?
A 0.55 B 0.61 C 0.90 D 1.64
© UCLES 2019 0620/21/M/J/19

3
19
4 Which statement about an atom of fluorine, 9 F, is correct?
A It contains more protons than neutrons.

B It contains a total of 28 protons, neutrons and electrons.
C Its isotopes contain different numbers of protons.
D Its nucleus contains 9 neutrons.
5 Which row describes the formation of single covalent bonds in methane?
A atoms share a pair of electrons both atoms gain a

noble gas electronic structure
B atoms share a pair of electrons both atoms have the same number
of electrons in their outer shell
C electrons are transferred from one both atoms gain a
atom to another noble gas electronic structure
D electrons are transferred from one both atoms have the same number
atom to another of electrons in their outer shell
6 Which statement describes the structure of an ionic compound?
A It is a giant lattice of oppositely charged ions.

B It is a giant lattice of positive ions in a ‘sea’ of electrons.
C It is a giant molecule of oppositely charged ions.
D It is a simple molecule of oppositely charged ions.
7 Propane burns in oxygen.
C3H8 + xO2 → 3CO2 + yH2O
Which values of x and y balance the equation?
x y
A 5 4
B 7 4
C 10 8
D 13 8

4
8 A tablet contains 0.080 g of ascorbic acid (Mr = 176).
What is the concentration of ascorbic acid when one tablet is dissolved in 200 cm3 of water?
A 9.1 × 10–5 mol / dm3
B 4.5 × 10–4 mol / dm3
C 9.1 × 10–2 mol / dm3
D 2.3 × 10–3 mol / dm3
9 Which statement about the electrolysis of copper(II) sulfate solution using carbon electrodes is
correct?
A A colourless gas is produced at the anode.

B A colourless gas is produced at the cathode.
C The colour of the electrolyte remains the same.
D The mass of both electrodes remains constant.
10 Aluminium metal is extracted from aluminium oxide by electrolysis.
Which ionic half-equation describes a reaction that occurs at the named electrode?
ionic half-equation electrode
A 2O2– → O2 + 2e– anode

B Al 3+ + 3e– → Al anode
C 2O2– → O2 + 4e– cathode
D Al 3+ + 3e– → Al cathode
11 Which statement about the hydrogen fuel cell is not correct?
A Chemical energy is converted into electrical energy.

B Hydrogen is oxidised.
C The reaction that takes place is endothermic.
D Water is the only product.
© UCLES 2019 0620/21/M/J/19

5
12 Nitrogen reacts with hydrogen to produce ammonia.
N2 + 3H2 → 2NH3
The reaction is exothermic. The bond energies are shown in the table.
bond energy
bond
in kJ / mol
N≡N 945
H–H 436
N–H 390
What is the energy change for this reaction?
A –1473 kJ / mol
B –87 kJ / mol
C 87 kJ / mol
D 1473 kJ / mol
13 Which change in reaction conditions increases both the collision rate and the proportion of
molecules with sufficient energy to react?
A addition of a catalyst
B increasing the concentration of a reactant
C increasing the surface area of a reactant
D increasing the temperature of the reaction
14 When blue-green crystals of nickel(II) sulfate are heated, water is produced and a yellow solid
remains. When water is added to the yellow solid, the blue-green colour returns.
Which process describes these changes?
A combustion
B corrosion
C neutralisation
D reversible reaction

6
15 The graph shows how the yield of product in a reversible reaction changes as the temperature
and pressure are changed.
All reactants and products are gases.
reactants products
yield of
product 300 °C
100 °C
pressure
Which row is correct for this reversible reaction?
side of reaction forward

with fewer moles reaction
A reactant exothermic
B reactant endothermic
C product endothermic
D product exothermic
16 Which changes represent oxidation?
1 2I– → I2 + 2e–
2 Cr(VI) → Cr(III)
3 Fe(II) → Fe(III)
17 Nitrogen(I) oxide, N2O, nitrogen(II) oxide, NO, and carbon monoxide, CO, are all non-metal
oxides.
They do not react with acids or bases.
A They are acidic oxides.

B They are amphoteric oxides.
C They are basic oxides.
D They are neutral oxides.
© UCLES 2019 0620/21/M/J/19

7
Y
X Z
19 Ethanoic acid is a weak acid.
Hydrochloric acid is a strong acid.
1 Ethanoic acid molecules are partially dissociated into ions.

2 1.0 mol / dm3 ethanoic acid has a higher pH than 1.0 mol / dm3 hydrochloric acid.
3 Ethanoic acid is always more dilute than hydrochloric acid.
4 Ethanoic acid is a proton acceptor.
20 The properties of an element are shown.
electrical conductivity density reaction with water

high low reacts violently with cold water
Which element has these properties?
A B
C
D

8
21 Which statement about elements in Group I and Group VII of the Periodic Table is correct?
A Bromine reacts with potassium chloride to produce chlorine.

B Iodine is a monatomic non-metal.
C Lithium has a higher melting point than potassium.
D Sodium is more reactive with water than potassium.
22 Which statement about elements in Group VIII of the Periodic Table is correct?
A They all have a full outer shell of electrons.

B They all react with Group I elements to form ionic compounds.
C They are all diatomic molecules.
D They are all liquids at room temperature.
23 The diagrams show the structure of two substances used to make electrical conductors.
X Y
Which statement correctly describes X and Y?
A X is a pure metal and Y is a compound.

B X is a pure metal and Y is an alloy.
C X is a solid and Y is a liquid.
D X is harder and stronger than Y.
© UCLES 2019 0620/21/M/J/19

9
24 Three metal compounds, P, Q and R, are heated using a Bunsen burner.
P colourless gas produced, which relights a glowing splint

Q colourless gas produced, which turns limewater milky
R no reaction
Which row shows the identity of P, Q and R?
P Q R
A magnesium carbonate potassium carbonate potassium nitrate

B magnesium carbonate potassium nitrate potassium carbonate
C potassium nitrate magnesium carbonate potassium carbonate
D potassium nitrate potassium carbonate magnesium carbonate
25 Zinc is extracted from its ore, zinc blende, using two chemical reactions.
1 2ZnS + 3O2 → 2ZnO + 2SO2
2 2ZnO + C → 2Zn + CO2
Which substance is reduced in reactions 1 and 2?
reaction 1 reaction 2
A O2 C
B O2 ZnO
C ZnS C
D ZnS ZnO

10
26 Four metals, zinc, M, copper and magnesium, are reacted with aqueous solutions of their
nitrates.
magnesium M copper zinc

metal
nitrate nitrate nitrate nitrate
magnesium key
zinc = reacts
M = no reaction
copper
What is the order of reactivity of these four metals starting with the most reactive?
A copper → zinc → M → magnesium
B copper → M → zinc → magnesium
C magnesium → M → zinc → copper
D magnesium → zinc → M → copper
27 Why is aluminium used to make containers for storing food?
B It has a high melting point.
C It is resistant to corrosion.
D It is strong.
28 Water can be treated by filtration then chlorination.
Which uses do not need water of this quality?
1 water for cooling in industry

2 water for washing clothes
3 water for drinking
© UCLES 2019 0620/21/M/J/19

11
29 Oxides of nitrogen are formed in car engines and are a source of air pollution.
To decrease this pollution, catalytic converters are fitted to car exhausts.
What happens to the oxides of nitrogen in the catalytic converter?
A combustion
B cracking
C oxidation
D reduction
P Q
iron painted iron
air
water
tube P tube Q
A falls rises
B no change rises
C rises falls
D rises no change
31 Ammonia is manufactured by the Haber Process.
N2(g) + 3H2(g) 2NH3(g)
Which conditions maximise the yield of ammonia?
A high high
B high low
C low high
D low low

12
32 The carbon cycle is shown.
atmospheric
carbon dioxide
X
respiration
decomposition Y
Z green plants
dead
organic matter
death and excretion
animals
Which row describes processes X, Y and Z?
X Y Z
A respiration combustion photosynthesis

B respiration photosynthesis combustion
C photosynthesis combustion respiration
D photosynthesis respiration combustion
33 Which row shows the conditions used in the Contact process?
catalyst
/ °C / atm
A 25 2 iron
B 25 200 iron
C 450 2 vanadium(V) oxide
© UCLES 2019 0620/21/M/J/19

13
34 The diagram represents a lime kiln used to heat limestone to a very high temperature.
waste gases
lime kiln
limestone
fuel in fuel in
air in air in
What leaves the kiln at X?
A calcium carbonate
B calcium hydroxide
C calcium oxide
D calcium sulfate
35 Which fuel could be gasoline?
Is it obtained
from petroleum?
yes no
Is it used as Is it used as
fuel for cars? fuel for cars?
yes no yes no
A B C D

14
36 Why is ethanol a member of the homologous series of alcohols but propane is not?
A Ethanol has two carbon atoms per molecule but propane has three.
B Ethanol can be made from ethene but propane is obtained from petroleum.
C Ethanol is a liquid but propane is a gas.
D Ethanol contains the same functional group as other alcohols but propane does not.
37 Chlorine reacts with methane.
1 The reaction takes place in the dark.

2 The reaction of chlorine with methane forms chloromethane.
3 Chloromethane reacts with chlorine to produce dichloromethane.
4 The reaction of chlorine with methane is an addition reaction.
1 Ethanoic acid contains the functional group –COOH.

2 Ethanoic acid reacts with carbonates to produce hydrogen.
3 Ethanoic acid turns Universal Indicator paper blue.
4 Ethanoic acid has a pH lower than pH 7.
39 The structure of an ester is shown.
CH3 C
OCH2CH2CH3
What is the name of the ester?
A ethyl propanoate
B methyl propanoate
C propyl ethanoate
D propyl methanoate
© UCLES 2019 0620/21/M/J/19

15
40 The structure of a polymer is shown.
O O O O
Which type of polymer is shown and by which process is it formed?
type of polymer formed by
A carbohydrate addition polymerisation

B carbohydrate condensation polymerisation
C polyester addition polymerisation
D polyester condensation polymerisation
© UCLES 2019 0620/21/M/J/19

Group
© UCLES 2019
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
16
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
lanthanoids
0620/21/M/J/19
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/21
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.

PUBLISHED
1 B 1
2 A 1
3 B 1
4 B 1
5 A 1
6 A 1
7 A 1
8 D 1
9 A 1
10 D 1
11 C 1
12 B 1
13 D 1
14 D 1
15 B 1
16 B 1
17 D 1
18 A 1
19 A 1
20 D 1
21 C 1
22 A 1
23 B 1
24 C 1
25 B 1
26 D 1
27 C 1
28 B 1

PUBLISHED
29 D 1
30 D 1
31 B 1
32 C 1
33 C 1
34 C 1
35 A 1
36 D 1
37 C 1
38 C 1
39 C 1
40 B 1

*7118832773*
CHEMISTRY 0620/31
1 hour 15 minutes

IB19 06_0620_31/2RP
2
1 The diagrams show part of the structures of five substances, A, B, C, D and E.
He Li+ Cl – Li+ Cl –
He
He Cl – Li+ Cl – Li+
He
He Li+ Cl – Li+ Cl –
He Cl – Li+ Cl – Li+
A B C
N
N
Cu Cu Cu Cu
N N
Cu Cu Cu Cu
N
Cu Cu Cu Cu
N
N N
N
N Cu Cu Cu Cu
D E
(a) A
nswer the following questions about these structures.
Each structure may be used once, more than once or not at all.
(i) Which two of these structures, A, B, C, D or E, are covalently bonded?
.................................................................. and ....................................................................

[2]
(ii) Which one of these structures, A, B, C, D or E, is a diatomic molecule?
........................................................................................................................................ [1]
(iii) Which one of these structures, A, B, C, D or E, is a compound?
........................................................................................................................................ [1]
(iv) Which one of these structures, A, B, C, D or E, is very soluble in water?
........................................................................................................................................ [1]
(v) Which one of these structures, A, B, C, D or E, is used in cutting tools?
........................................................................................................................................ [1]
(vi) Which one of these structures, A, B, C, D or E, is used in electrical wiring?
........................................................................................................................................ [1]
© UCLES 2019 0620/31/M/J/19

3
(b) Substance B is an element.
What is meant by the term element ?
.....................................................................................................................................................
............................................................................................................................................... [1]
[Total: 8]

4
2 This question is about iron and iron compounds.
(a) Name the main ore of iron.
............................................................................................................................................... [1]
(b) In a blast furnace used for the extraction of iron, carbon reacts with oxygen from the air to form
carbon monoxide.
....C + ..... 2CO

[2]
(c) In the hotter parts of the furnace, carbon reacts with the iron(III) oxide present in the iron ore.
3C + Fe2O3 3CO + 2Fe
How does this equation show that carbon is oxidised?
.....................................................................................................................................................
............................................................................................................................................... [1]
(d) L
imestone is added to the blast furnace. The limestone is converted into calcium oxide and
carbon dioxide. The reaction is endothermic.
heat
CaCO3 CaO + CO2
(i) What type of chemical reaction is this?
........................................................................................................................................ [1]
(ii) W
hat type of oxide is calcium oxide?
..............................................................................................................................................
........................................................................................................................................ [2]
(e) Iron is a metal.
Give three physical properties that are characteristic of metals.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
3 ..................................................................................................................................................
[3]
© UCLES 2019 0620/31/M/J/19

5
(f) The structure of a compound of iron is shown.
O
OC C CO
OC Fe Fe CO
C
OC O CO
C
O
educe the molecular formula of this compound to show the number of iron, carbon and
D
oxygen atoms.
............................................................................................................................................... [1]
[Total: 11]

6
3 (a) The table shows the percentage by mass of the elements on Earth and in the Universe.
percentage by percentage by mass

element
mass on Earth in the Universe
helium 0.0 21.0
hydrogen 0.1 76.0
iron 35.0 1.0
magnesium 14.0 0.1
oxygen 29.0 0.8
silicon 14.0 0.1
sulfur 2.9 0.1
other elements 0.9
total 100.0 100.0
Answer these questions using only the information in the table.
(i) Deduce the percentage by mass of other elements present on Earth.
.............................. % [1]
(ii) Which non-metallic element is present on Earth in the greatest percentage by mass?
........................................................................................................................................ [1]
(iii) G
ive two major differences in the percentage by mass of the elements on Earth and in the
Universe.
1 ...........................................................................................................................................
..............................................................................................................................................
2 ...........................................................................................................................................
..............................................................................................................................................
[2]
(b) Complete the diagram to show the electron arrangement in an oxygen atom.
[1]
© UCLES 2019 0620/31/M/J/19

7
(c) Helium, neon and argon are noble gases.
(i) Explain, in terms of the electronic structure, why neon is unreactive.
..............................................................................................................................................
........................................................................................................................................ [1]
(ii) State one use of argon.
........................................................................................................................................ [1]
[Total: 7]

8
4 This question is about iodine and compounds of iodine.
(a) U
se the kinetic particle model to describe the separation between the molecules and the type
of motion of the molecules in:
●● solid iodine ...........................................................................................................................
.....................................................................................................................................................
●● iodine gas. ...........................................................................................................................
.....................................................................................................................................................
[4]
(b) T
he graph shows how the volume of iodine gas changes with pressure. The temperature is
kept constant.
volume of
iodine gas
0
0 pressure
Describe how the volume of iodine gas changes with pressure.
.....................................................................................................................................................
............................................................................................................................................... [1]
(c) (i) C
omplete the word equation to show the halogen and halide compound which react to
form the products iodine and potassium bromide.
........................ ........................ potassium

+ iodine +
bromide
........................
[2]
(ii) E
xplain, in terms of the reactivity of the halogens, why aqueous iodine does not react with
aqueous potassium chloride.
..............................................................................................................................................
........................................................................................................................................ [1]
© UCLES 2019 0620/31/M/J/19

9
(d) Iodine reacts with aqueous sodium thiosulfate, Na2S2O3.
(i) Balance the chemical equation for this reaction.
.....Na2S2O3 + I2 Na2S4O6 + .....NaI

[2]
(ii) The energy level diagram for this reaction is shown.
reactants
energy
products
Explain how this diagram shows that the reaction is exothermic.
..............................................................................................................................................
........................................................................................................................................ [1]
(e) Describe a test for iodide ions.
test ..............................................................................................................................................
observations ...............................................................................................................................
[2]
(f) Molten sodium iodide is electrolysed.
Predict the product at the positive electrode.
............................................................................................................................................... [1]
[Total: 14]

10
5 oal gas is made by heating coal in the absence of air.

C
The list shows the main gases present in coal gas.
carbon dioxide
carbon monoxide
ethene
hydrogen
methane
nitrogen
(a) (i) Which one of these gases is an alkane?
........................................................................................................................................ [1]
(ii) Draw the structure of a molecule of ethene. Show all of the atoms and all of the bonds.
[1]
(iii) D
escribe how aqueous bromine can be used to tell the difference between methane and
ethene.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
© UCLES 2019 0620/31/M/J/19

11
(b) Ethene molecules react with each other to form poly(ethene).
(i) What is the name given to this type of chemical reaction?
........................................................................................................................................ [1]
(ii) Which one of the following words describes the ethene molecules in this reaction?
elements mixtures monomers polymers

[1]
(iii) Poly(ethene) is a non-biodegradable plastic.
What is meant by the term non-biodegradable?
..............................................................................................................................................
........................................................................................................................................ [1]
(iv) Describe one pollution problem caused by non-biodegradable plastics.
..............................................................................................................................................
........................................................................................................................................ [1]
(c) Ethanol can be made from ethene and one other reactant.
●● Name the other reactant.
.....................................................................................................................................................
●● State the conditions needed to make ethanol from ethene.
.....................................................................................................................................................
.....................................................................................................................................................
[3]
[Total: 11]

12
6 This question is about copper and copper compounds.
escribe how you could prepare a pure sample of crystals of hydrated copper(II) sulfate using
(a) D
dilute sulfuric acid and an excess of copper(II) oxide.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
(b) Anhydrous copper(II) sulfate is used to test for water.
CuSO4 + 5H2O CuSO4.5H2O

anhydrous hydrated
copper(II) sulfate copper(II) sulfate
(i) What is meant by the symbol ?
........................................................................................................................................ [1]
(ii) How can hydrated copper(II) sulfate be changed into anhydrous copper(II) sulfate?
........................................................................................................................................ [1]
(c) C omplete the table to calculate the relative formula mass of anhydrous copper(II) sulfate,
CuSO4.
number relative
type of atom
of atoms atomic mass
copper 1 64 1 × 64 = 64
sulfur
oxygen
relative formula mass = ...............................

[2]
© UCLES 2019 0620/31/M/J/19

13
(d) C
omplete the table to show the number of electrons, protons and neutrons in the sulfur atom
and copper ion shown.

electrons neutrons protons
16S
34
29Cu
63 2+
29
[4]
(e) Alloys of copper are used to make coins.
(i) What is meant by the term alloy?
..............................................................................................................................................
........................................................................................................................................ [1]
(ii) Suggest why an alloy of copper is used to make coins instead of using pure copper.
........................................................................................................................................ [1]
[Total: 13]

14
7 A student investigates the rate of reaction of small pieces of calcium carbonate with an excess of
hydrochloric acid of concentration 1 mol / dm3.
CaCO3(s) + 2HCl (aq) CaCl 2(aq) + CO2(g) + H2O(l)
(a) Name the salt formed when calcium carbonate reacts with hydrochloric acid.
............................................................................................................................................... [1]
(b) The graph shows how the mass of the reaction mixture changes with time.
200.0
199.8
199.6
mass of
reaction
mixture
/g 199.4
199.2
199.0
198.8
0 20 40 60 80 100 120 140
time / s
(i) State why the reaction mixture decreases in mass.
........................................................................................................................................ [1]
(ii) Calculate the loss in mass during the first 40 seconds of the experiment.
.............................. g [1]
© UCLES 2019 0620/31/M/J/19

15
(iii) T he experiment is repeated using hydrochloric acid of concentration 2 mol / dm3.

Draw a line on the grid for the experiment using hydrochloric acid of concentration
2 mol / dm3.[2]
(iv) In the experiment, when 2.00 g of calcium carbonate is used, the loss in mass of the
reaction mixture is 0.88 g.
Calculate the loss in mass when 0.50 g of calcium carbonate is used.
loss in mass = .............................. g [1]
(v) T he experiment is repeated using the same mass of different sized pieces of
calcium carbonate.
The sizes of the pieces of calcium carbonate are:
● powder
● small pieces
● large pieces.
Complete the table by writing the sizes of the pieces of calcium carbonate in the first
column.
size of pieces of initial rate of loss

calcium carbonate in mass in g / s
0.005
0.030
0.100
[1]
[Total: 7]

16
8 (a) Sulfur dioxide is a pollutant in the air.
(i) State one source of sulfur dioxide in the air.
........................................................................................................................................ [1]
(ii) S
ulfur dioxide is oxidised to sulfur trioxide in the air.
Oxides of nitrogen act as catalysts for this reaction.
What is meant by the term catalyst ?
..............................................................................................................................................
........................................................................................................................................ [1]
(iii) Sulfur trioxide dissolves in rainwater to form acid rain.
Which one of the following pH values could be the pH of acid rain?

[1]
(iv) State one adverse effect of acid rain on buildings.
........................................................................................................................................ [1]
(b) Sulfur dioxide melts at –73 °C and boils at –10 °C.
hat is the physical state of sulfur dioxide at –20 °C?

W
.....................................................................................................................................................
............................................................................................................................................... [2]
© UCLES 2019 0620/31/M/J/19

17
(c) Excess sulfuric acid reacts with ammonia to make a salt which can be used as a fertiliser.
State the name of the salt formed when excess sulfuric acid reacts with ammonia.
............................................................................................................................................... [1]
(d) The table shows some observations about the reactivity of four metals with dilute sulfuric acid.
metal reaction with sulfuric acid

iron a slow stream of bubbles is seen
magnesium a rapid stream of bubbles is seen
nickel a few bubbles slowly form
tungsten no bubbles are seen
se the information in the table to put the four metals in order of their reactivity.
U
Put the least reactive metal first.
[2]
[Total: 9]

18
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© UCLES 2019 0620/31/M/J/19

19
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© UCLES 2019 0620/31/M/J/19

Group
© UCLES 2019
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
20
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/31/M/J/19
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/31
MARK SCHEME
Maximum Mark: 80
Published
Teachers.

PUBLISHED
marking principles.
descriptors.

PUBLISHED

PUBLISHED
1(a)(i) B / diamond (1) 2
D / nitrogen / N2 (1)
1(a)(ii) D / nitrogen / N2 1
1(a)(iii) C / lithium chloride / LiCl 1
1(a)(iv) C / lithium chloride / LiCl 1
1(a)(v) B / diamond 1
1(a)(vi) E / copper / Cu 1
1(b) substance in which all the atoms have the same proton number / substance containing (only) one type of atom 1
2(a) hematite 1
2(b) 2 (C) (1) 2
O2 (1)
2(c) carbon gains oxygen (from Fe2O3) / oxygen (from Fe2O3) combines with carbon 1
2(d)(i) thermal decomposition 1
2(d)(ii) basic oxide (1) 2
calcium is a metal (oxide) (1)

PUBLISHED
2(e) any three from: 3

• conduct electricity
• conduct heat
• malleable
• ductile
• shiny / lustrous
2(f) Fe2C9O9 1
3(a)(i) 5.0% 1
3(a)(ii) oxygen 1
3(a)(iii) any two from: 2

• more hydrogen in Universe (or reverse argument)
• more helium in Universe (or reverse argument)
• more oxygen on Earth (or reverse argument)
• more magnesium on Earth (or reverse argument)
• more iron on Earth (or reverse argument)
• more silicon on Earth (or reverse argument)
• more sulfur on Earth (or reverse argument)
3(b) 2 electrons in inner shell AND 6 electrons in outer shell AND no additional shells of electrons 1
3(c)(i) has complete outer (electron) shell / has full outer (electron) shell / outer shell cannot gain or lose electron(s) 1
3(c)(ii) lamps / inert atmosphere (in metal extraction) 1

PUBLISHED
4(a) solid: 4
particles touching / particles close together (1)
particles (only) vibrating / not moving from place to place (1)
gas:
particles far apart (1)
particles moving fast / particles moving randomly / particles moving in any direction (1)
4(b) increasing the pressure decreases the volume / decreasing the pressure increases the volume / the higher the volume, the lower 1
the pressure
4(c)(i) bromine (1) 2
potassium iodide (1)
4(c)(ii) chlorine more reactive than iodine / iodine less reactive than chlorine 1
4(d)(i) 2 (Na2S2O3) (1) 2
2 (NaI) (1)
4(d)(ii) the energy of the reactants is more than the energy of the products / the energy of the products is less than the energy of the 1
reactants / the reactants lose energy when they form products
4(e) add (acidified aqueous) silver nitrate (1) 2
yellow precipitate (1)
4(f) iodine / I2 1

PUBLISHED
5(a)(i) methane 1
5(a)(ii) 1
5(a)(iii) with methane (aqueous) bromine remains orange (1) 2
with ethene (aqueous) bromine decolourised (1)
5(b)(i) polymerisation / addition 1
5(b)(ii) monomers 1
5(b)(iii) cannot be decomposed by organisms / cannot be broken down by bacteria / cannot be broken down by fungi 1
5(b)(iv) gets stuck in gullets of birds / gets stuck in gullets of animals / blocks drains 1
5(c) steam (1) 3
high temperature (1)
catalyst (1)

PUBLISHED
6(a) any three from: 3

• heat copper oxide with sulfuric acid
• filter off (excess) copper oxide
• heat filtrate to point of crystallisation / heat (copper sulfate) solution to point of crystallisation
• dry between filter papers / dry in drying oven
6(b)(i) reversible reaction 1
6(b)(ii) heat / warm 1
6(c) 160 (2 marks) 2
if 2 marks not scored 1 mark for S = (1 × 32) = 32 OR O (= 4 × 16) = 64
6(d) electrons in S = 16 (1) 4
electrons in Cu2+ = 27 (1)
neutrons in S = 18 AND neutrons in Cu2+ = 34 (1)
protons in S = 16 (1)
6(e)(i) mixture of metal and other elements 1
6(e)(ii) (alloy) more resistant to wear / stronger / harder / more resistant to corrosion ORA for copper 1

PUBLISHED
7(a) calcium chloride 1
7(b)(i) gas released / gas escapes / gas lost 1
7(b)(ii) 0.7 (g) 1
7(b)(iii) line steeper than original and starting from 0 and 200.0 g (1) 2
line ends up at same final mass AND levels off at or before 104 s (1)
7(b)(iv) 0.22 (g) 1
7(b)(v) large pieces → 0.005 1

small pieces → 0.030
powder → 0.100
8(a)(i) burning fossil fuels / volcanoes / heating (sulfide) ores 1
8(a)(ii) substance which speeds up a reaction / substance which increases the rate of reaction 1
8(a)(iii) pH4 1
8(a)(iv) erodes buildings (made of carbonate rocks) / wears away buildings (made of carbonate rocks) / reacts with mortar / corrodes iron 1
work / corrodes metal
8(b) liquid (1) 2
–20 °C is between the melting and boiling point / –20 °C is above melting point but lower than boiling point (1)

PUBLISHED
8(c) ammonium sulfate 1
8(d) tungsten < nickel < iron < magnesium (2) 2
if 2 marks not scored 1 mark for one consecutive pair reversed

*1251990751*
CHEMISTRY 0620/41
1 hour 15 minutes

IB19 06_0620_41/3RP
2
BLANK PAGE
© UCLES 2019 0620/41/M/J/19

3
1 This question is about the structures of atoms and ions.
(a) Define the term proton number.
.....................................................................................................................................................
............................................................................................................................................... [2]
(b) (i) Complete the table to show the number of protons, neutrons and electrons present in
24
atoms of 12 Mg and 12
26
Mg.

12Mg
24
12Mg
26
[2]
24
(ii) What term is used to describe atoms of the same element, such as 12 Mg and 12
26
Mg?
........................................................................................................................................ [1]
24
(iii) Explain why the chemical properties of 12 Mg and 12
26
Mg are the same.
..............................................................................................................................................
........................................................................................................................................ [2]
(c) Complete the table to identify the atoms and ions which have the following numbers of protons,
neutrons and electrons.

11Na
23 +
11 12 10
4 5 4
17 20 18
[4]
(d) State the electronic structure of the following atom and ion.
Al ................................
S2– ...............................
[2]
[Total: 13]

4
2
Z is a covalent substance. In an experiment, a sample of pure solid Z was continually heated for
11 minutes.
The graph shows how the temperature of the sample of pure Z changed during the first 9 minutes.
240
220
200
180
160
140
temperature
/ °C 120
100
80
60
40
20
0
0 1 2 3 4 5 6 7 8 9 10 11 12
time / minutes
(a) What is the melting point of pure Z?
.............................. °C [1]
(b) The sample of pure Z began to boil at 9 minutes. It was boiled for 2 minutes.
Use this information to sketch on the grid how the temperature of the sample of pure Z changed
between 9 minutes and 11 minutes. [1]
(c) The sample of pure Z was continually heated between 2 minutes and 5 minutes.
Explain, in terms of attractive forces, why there was no increase in the temperature of the
sample of pure Z between 2 minutes and 5 minutes.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
© UCLES 2019 0620/41/M/J/19

5
(d) Describe how the motion of particles of pure Z changed from 0 minutes to 2 minutes.
.....................................................................................................................................................
............................................................................................................................................... [2]
(e) The experiment was repeated using a solid sample of impure Z.
Suggest the differences, if any, in the melting point and boiling point of the sample of impure Z
compared to the sample of pure Z.
melting point ...............................................................................................................................
boiling point ................................................................................................................................

[2]
(f) A sample of pure Z was allowed to cool from 120 °C to 20 °C. The total time taken was 8 minutes.
Starting from point ×, sketch on the grid how the temperature of the sample of pure Z changed
between 0 minutes and 8 minutes.
200
180
160
140
120
temperature
/ °C 100
80
60
40
20
0
0 1 2 3 4 5 6 7 8 9 10 11 12
time / minutes
[2]
[Total: 10]

6
3 Zinc and copper are elements next to each other in the Periodic Table.
(a) Zinc is obtained from zinc blende in a two-step process.
●● In step 1, zinc blende is converted into zinc oxide.
●● In step 2, zinc oxide is converted into zinc in a blast furnace.
Outline how each of these steps are done.
In your answer:

●● give one chemical equation for each step
●● describe how zinc is removed from the blast furnace in step 2.
step 1 .........................................................................................................................................
.....................................................................................................................................................
chemical equation .......................................................................................................................
step 2 .........................................................................................................................................
.....................................................................................................................................................
chemical equation .......................................................................................................................
removal of zinc in step 2 ............................................................................................................
.....................................................................................................................................................
[5]
(b) Name the alloy formed when zinc is mixed with copper.
............................................................................................................................................... [1]
(c) Copper is a transition element. It can have variable oxidation states.
State two other chemical properties of transition elements which make them different from
Group I elements.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
[2]
© UCLES 2019 0620/41/M/J/19

7
(d) A compound of copper can be used to test for water.
(i) State the full name of this compound of copper.
........................................................................................................................................ [1]
(ii) State the colour change that occurs when water is added to this compound of copper.
from .............................................................. to .................................................................

[2]
(e) Aqueous potassium iodide reacts with aqueous copper(II) sulfate to produce iodine.
(i) Balance the chemical equation for this reaction.
KI + CuSO4 CuI + I2 + K2SO4

[2]
(ii) Deduce the charge on the copper ion in CuI.
........................................................................................................................................ [1]
(iii) In terms of electron transfer, explain why copper is reduced in this reaction.
........................................................................................................................................ [1]
(iv) Identify the reducing agent.
........................................................................................................................................ [1]
[Total: 16]

8
4
Ethanoic acid is a weak acid and hydrochloric acid is a strong acid.
Both ethanoic acid and hydrochloric acid dissociate in aqueous solution.
(a) (i) Define the term acid.
........................................................................................................................................ [1]
(ii)
The chemical equation shows the changes which occur when the strong acid,
hydrochloric acid, is added to water.
HCl (aq) H+(aq) + Cl –(aq)
Complete the chemical equation to show the changes which occur when the weak acid,
ethanoic acid, is added to water.
CH3COOH(aq) ............................................................................................................... [2]
(b) A student does experiments to show that hydrochloric acid is a strong acid and ethanoic acid is
a weak acid. The student adds an excess of hydrochloric acid and an excess of ethanoic acid
to separate samples of lumps of calcium carbonate.
Only the identity of the acid is changed between the experiments. All other conditions are kept
the same.
(i) State two observations which would show that hydrochloric acid is a stronger acid than
ethanoic acid.
1 ...........................................................................................................................................
2 ...........................................................................................................................................
[2]
(ii) The student uses the same size container and checks that the pressure is the same for
each experiment.
State three other conditions which must be kept the same to ensure fair testing.
1 ...........................................................................................................................................
2 ...........................................................................................................................................
3 ...........................................................................................................................................
[3]
© UCLES 2019 0620/41/M/J/19

9
(c) Hydrochloric acid produces salts called chlorides.
Magnesium carbonate reacts with hydrochloric acid to produce magnesium chloride.
MgCO3 + 2HCl MgCl 2 + H2O + CO2
A student used 50.00 cm3 of 2.00 mol / dm3 hydrochloric acid in an experiment to produce

magnesium chloride.
Calculate the mass, in g, of magnesium carbonate needed to react exactly with 50.00 cm3 of
2.00 mol / dm3 hydrochloric acid using the following steps.
●● Calculate the number of moles of HCl present in 50.00 cm3 of 2.00 mol / dm3 HCl.
.............................. mol
●● etermine the number of moles of MgCO3 which would react with 50.00
D cm3 of
2.00 mol / dm HCl.
3
.............................. mol
●● Calculate the relative formula mass, Mr, of MgCO3.
Mr of MgCO3 = ..............................
●● Calculate the mass of MgCO3 needed to react exactly with 50.00 cm3 of 2.00 mol / dm3 HCl.
mass = .............................. g
[4]

10
(d)
A student prepares crystals of magnesium chloride by adding an excess of
magnesium carbonate to 50.00 cm3 of 2.00 mol / dm3 hydrochloric acid.
The student filters the mixture and rinses the residue.
(i) Why does the student add an excess of magnesium carbonate?
........................................................................................................................................ [1]
(ii) Why does the student rinse the residue?
........................................................................................................................................ [1]
(iii) Describe how the student would obtain pure crystals of magnesium chloride from the
filtrate.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [3]
(e) Silver chloride, AgCl, is insoluble. It can be made by a precipitation reaction between aqueous
barium chloride and a suitable aqueous silver salt.
(i) What is meant by the term precipitate?
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) Name a suitable silver salt to use to prepare silver chloride.

Complete the chemical equation to show the formation of insoluble silver chloride from
aqueous barium chloride and the silver salt you have named.
name of a suitable silver salt ...............................................................................................
BaCl 2 + ..................... ..................... + .....................

[3]
[Total: 22]
© UCLES 2019 0620/41/M/J/19

11
5 The structures of five alkenes, A, B, C, D and E, are shown.
A B C
H H H CH3 H CH2CH3
C C C C C C
H H H H H H
D E
H CH2CH2CH3 H CH2CH2CH2CH3
C C C C
H H H H
(a) What is the general formula of alkenes?
............................................................................................................................................... [1]
(b) What is the molecular formula of alkene D?
............................................................................................................................................... [1]
(c) Predict which alkene, A, B, C, D or E, has the highest boiling point.

alkene .............................
explanation .................................................................................................................................
.....................................................................................................................................................
[2]
(d) Which alkene, A, B, C, D or E, diffuses most quickly?

alkene .............................
explanation .................................................................................................................................
.....................................................................................................................................................
[2]

12
(e) A student added aqueous bromine to alkene C.
C
H CH2CH3
C C
H H
Describe the colour change seen and draw the structure of the product. Show all of the atoms
and all of the bonds.
colour change from ........................................................ to ......................................................
structure
[2]
(f) Two different alcohols can be produced from alkene B by an addition reaction.
B
H CH3
C C
H H
(i) Draw the structures of the two alcohols. Show all of the atoms and all of the bonds.
[2]
(ii) State the reagent and conditions needed to produce an alcohol from alkene B.
reagent ................................................................................................................................
conditions ............................................................................................................................
..............................................................................................................................................
[3]
© UCLES 2019 0620/41/M/J/19

13
(g) Alkene C can be converted into a polymer.
C
H CH2CH3
C C
H H
(i) What type of polymerisation occurs?
........................................................................................................................................ [1]
(ii) Suggest the name of the polymer formed.
........................................................................................................................................ [1]
(iii) Complete the chemical equation to show this polymerisation.
H CH2CH3
n C C
H H
[3]
(iv) State the empirical formula of the polymer formed.
........................................................................................................................................ [1]
[Total: 19]

14
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© UCLES 2019 0620/41/M/J/19

15
BLANK PAGE
© UCLES 2019 0620/41/M/J/19

Group
© UCLES 2019
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/41/M/J/19
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/41
MARK SCHEME
Maximum Mark: 80
Published
Teachers.

PUBLISHED
marking principles.
descriptors.

PUBLISHED

PUBLISHED
1(a) number of protons (1) 2
protons in the nucleus (of an atom) (1)
1(b)(i) 12p 12n 12e (1) 2
12p 14n 12e (1)
1(b)(ii) isotope(s) 1
1(b)(iii) same number of electrons (1) 2
(same number) of electrons in the outer shell (1)
1(c) 9 Be
4 4
any element symbol with a single negative charge (1)
use of Cl (1)
use of 3717 (1)
1(d) 2 8 3 (1) 2
2 8 8 (1)
2(a) 80(°C) (1) 1
2(b) horizontal line from end of graph at minute 9 to minute 11 (1) 1
2(c) energy is used to break bonds / overcome attraction (1) 2
between molecules (1)

PUBLISHED
2(d) vibrations (1) 2
increase (1)
2(e) melting point decreases (1) 2
boiling point increases (1)
2(f) decrease from 120 °C to 80 °C and horizontal line at 80 °C (1) 2
decrease from horizontal line to finish at 20 °C at 8 mins (1)
3(a) roast zinc blende (in air) (1) 5
2ZnS + 3O2 → 2ZnO + 2SO2 (1)
add/react with coke (1)
ZnO + C → Zn + CO OR 2ZnO + C → 2Zn + CO2 (1)
(zinc is) distilled (1)
3(b) brass 1
3(c) form coloured compounds / ions (1) 2
act as catalysts (1)
3(d)(i) anhydrous copper(II) sulfate 1
3(d)(ii) white (1) 2
blue (1)

PUBLISHED
3(e)(i) 4KI + 2CuSO4 → 2CuI + I2 + 2K2SO4 (2) 2
3(e)(ii) 1+ 1
3(e)(iii) gains electron(s) 1
3(e)(iv) KI / potassium iodide / iodide (ions) / I– 1
4(a)(i) proton donor 1
4(a)(ii) (CH3COOH) ⇌ CH3COO– (1) + H+ (1) 2
4(b)(i) any two from: 2

• faster rate of fizzing
• solid dissolves quicker / disappears quicker / gets smaller quicker
• fizzing stops quicker
• dissolving stops quicker
4(b)(ii) any three from: 3

• temperature
• volume (of acid)
• concentration (of acid)
• mass / amount (of CaCO3)
• particle size / surface area (of CaCO3)

PUBLISHED
4(c) 50.0 4
M1 mol of HCl = 2.00 × = 0.1(00) mol (1)
1000
M1
M2 mol of MgCO3 = = 0.1(00) / 2 = 0.05(00) (1)
2
M3 Mr of MgCO3 = 84 (1)
M4 mass of MgCO3 = M3 × M2 = 84 × 0.05(00) = 4.2(0)g (1)
4(d)(i) to remove the acid / make sure all the acid is used up / no acid is left over 1
4(d)(ii) to make sure all the filtrate / MgCl2 / salt goes through / no MgCl2 left behind 1
4(d)(iii) evaporation mark (1) 3
the starting of crystallisation mark (1)
drying the crystals mark (1)
4(e)(i) a solid (1) 2
which forms when two solutions are mixed / reacted / added (1)
4(e)(ii) (silver) nitrate (1) 3
BaCl2 + 2AgNO3 → 2AgCl + Ba(NO3)2
formulae (1)
balance(1)

PUBLISHED
5(a) CnH2n (1) 1
5(b) C5H10 (1) 1
5(c) E (1) 2
it has the longest carbon chain (1)
5(d) A (1) 2
it has the lowest Mr (1)
5(e) orange to colourless (1) 2
structure of 1,2-dibromobutane (1)
5(f)(i) structure of propan-1-ol (1) structure of propan-2-ol (1) 2
5(f)(ii) steam (1) 3
catalyst (1)
one other condition: either 60 atm pressure OR 300 °C (1)
5(g)(i) addition 1
5(g)(ii) poly(but-1-ene) 1

PUBLISHED
5(g)(iii) M1 2 C atoms (only) with a single bond between them linked to the continuation bonds shown 3
M2 correct repeat unit showing one C2H5 / CH2CH3 side chain attached to one of the C atoms in M1
M3 correct use of ‘n’
5(g)(iv) CH2 1

CHEMISTRY 0620/51
*7806266751*
This document gives details of how to prepare for and administer the practical exam.
The information in this document and the identity of any materials supplied by Cambridge International
are confidential and must NOT reach candidates either directly or indirectly.
The supervisor must complete the report at the end of this document and return it with the scripts.
If you have any queries regarding these confidential instructions, contact Cambridge International stating the
centre number, the syllabus and component number and the nature of the query.
email info@cambridgeinternational.org
phone +44 1223 553554
fax +44 1223 553558
IB19 06_0620_51/CI/2RP
2
General information about practical exams

Centres must follow the guidance on science practical exams given in the Cambridge Handbook.
Safety
Supervisors must follow national and local regulations relating to safety and first aid.
Only those procedures described in the question paper should be attempted.
Supervisors must inform candidates that materials and apparatus used in the exam should be treated
with caution. Suitable eye protection should be used where necessary.
The following hazard codes are used in these confidential instructions, where relevant:

Hazard data sheets relating to substances used in this exam should be available from your chemical
supplier.
Before the exam
● The packets containing the question papers must not be opened before the exam.
● It is assumed that standard school laboratory facilities, as indicated in the Guide to Planning
Practical Science, will be available.
● Spare materials and apparatus for the tasks set must be available for candidates, if required.
During the exam
● It must be made clear to candidates at the start of the exam that they may request spare materials
and apparatus for the tasks set.
● Where specified, the supervisor must perform the experiments and record the results as instructed.
This must be done out of sight of the candidates, using the same materials and apparatus as the
candidates.
● Any assistance provided to candidates must be recorded in the supervisor’s report.
● If any materials or apparatus need to be replaced, for example, in the event of breakage or loss,
this must be recorded in the supervisor’s report.
After the exam
● The supervisor must complete a report for each practical session held and each laboratory used.
● Each packet of scripts returned to Cambridge International must contain the following items:
● the scripts of the candidates specified on the bar code label provided
● the supervisor’s results relevant to these candidates
● the supervisor’s reports relevant to these candidates
● seating plans for each practical session, referring to each candidate by candidate number
● the attendance register.
© UCLES 2019 0620/51/CI/M/J/19

3
Specific information for this practical exam
During the exam, the supervisor (NOT the invigilator) must do the experiments in Questions
1 and 2 and record the results on a spare copy of the question paper, clearly labelled
‘supervisor’s results’.
Materials and apparatus for Question 1
Each candidate will require the following materials and apparatus. Labels do not need to include
concentrations.
● 50 cm3 of aqueous barium nitrate, Ba(NO3)2, of concentration 0.33 mol / dm3 labelled aqueous
barium nitrate
● 50 cm3 of aqueous sodium carbonate, Na2CO3, of concentration 0.33 mol / dm3 labelled aqueous
sodium carbonate
● access to water and distilled water
● 10 cm3 measuring cylinder
● 50 cm3 burette with stand and clamp
● funnel for filling burette
● 6 × identical test-tubes, capable of holding 15 cm3
● test-tube rack
● glass stirring rod
● stop-clock or timer which can measure to an accuracy of 1 s
● marker pen to write on glass
● ruler with millimetre graduations
● teat pipette

4
concentrations.
● 10 cm3 of aqueous hydrochloric acid of concentration 2.0 mol / dm3 in a stoppered

test-tube labelled solution F

● 0.1 g of powdered calcium carbonate, CaCO3, in a stoppered boiling tube labelled
solid G

● aqueous barium nitrate of sufficient concentration to give a positive sulfate test
[MH][N] ● aqueous silver nitrate of sufficient concentration to give a positive halide test
[C] ● aqueous nitric acid of concentration 1.0 mol / dm3
[C] ● aqueous sodium hydroxide of concentration 1.0 mol / dm3
[MH][N] ● aqueous ammonia of concentration 1.0 mol / dm3
[F] ● 3 cm strip of magnesium ribbon
[MH] ● limewater and apparatus used to test for carbon dioxide

● distilled water

● pH indicator paper and chart

● red and blue litmus paper


● splints

● Bunsen burner and means to light it

● rack of test-tubes

● teat pipettes

● spatula
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6
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7
Supervisor’s report
Syllabus and component number /
Centre number
Centre name ��
Time of the practical session ��
Laboratory name/number ��
Give details of any difficulties experienced by the centre or by candidates (include the relevant
candidate names and candidate numbers).
You must include:
● ny difficulties experienced by the centre in the preparation of materials

a
● any difficulties experienced by candidates, e.g. due to faulty materials or apparatus
● any specific assistance given to candidates.

8
Declaration
1 Each packet that I am returning to Cambridge International contains the following items:
the scripts of the candidates specified on the bar code label provided
the supervisor’s results relevant to these candidates
the supervisor’s reports relevant to these candidates
seating plans for each practical session, referring to each candidate by candidate number
the attendance register
2 here the practical exam has taken place in more than one practical session, I have clearly labelled
W
the supervisor’s results, supervisor’s reports and seating plans with the time and laboratory name/
number for each practical session.
3 I have included details of difficulties relating to each practical session experienced by the centre or
by candidates.
4 I have reported any other adverse circumstances affecting candidates, e.g. illness, bereavement or
temporary injury, directly to Cambridge International on a special consideration form.
Signed ....................................................................................................... (supervisor)
Name (in block capitals) ............................................................................
© UCLES 2019 0620/51/CI/M/J/19

*6790855622*
CHEMISTRY 0620/51
1 hour 15 minutes

Total
IB19 06_0620_51/2RP
2
1
You are going to investigate the reaction between aqueous sodium carbonate and aqueous
barium nitrate.
Read all the instructions carefully before starting the experiment.

Instructions
You are going to do one experiment.
●● ill the burette up to the 0.0 cm3 mark with the aqueous sodium carbonate.
F
●● Label the test-tubes 1, 2, 3, 4, 5 and 6 and place them in order in the test-tube rack.
●● Use the measuring cylinder to pour 6 cm3 of the aqueous barium nitrate into each of the six
test-tubes.
●● Add 1.0 cm3 of aqueous sodium carbonate from the burette to test-tube 1.
Using the glass rod, carefully stir the contents of each of the test-tubes. Leave the contents of the
test-tubes to stand for at least 10 minutes.
You should start Question 2 while you are waiting for the solid formed in the test‑tubes to

settle.
(a) After 10 minutes, use a ruler to measure the height of the solid formed in each test-tube.
test-tube volume of aqueous height of solid

number sodium carbonate / cm3 / mm
6
[4]
© UCLES 2019 0620/51/M/J/19

3
(b) Plot your results on the grid. Draw a line of best fit.
height of
solid / mm
0 1 2 3 4 5 6 7 8
volume of aqueous sodium carbonate / cm3
[3]

4
(c)
From your graph, deduce the height of the solid formed when 3.0
cm3 of aqueous
sodium carbonate is added to 6 cm of aqueous barium nitrate.
3
............................................................................................................................................... [3]
(d) Describe the trend in the heights of the solids formed in test-tubes 1–6.
.....................................................................................................................................................
............................................................................................................................................... [1]
(e) Explain one improvement you could make to the experiment to obtain more accurate results
for the heights of the solid formed.
improvement ...............................................................................................................................
explanation .................................................................................................................................
.....................................................................................................................................................
[2]
(f) Suggest a different method to measure the amount of solid formed during the experiment.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
(g) Suggest how the reliability of the results could be checked.
.....................................................................................................................................................
............................................................................................................................................... [1]
(h) What type of chemical reaction occurs when aqueous sodium carbonate reacts with aqueous
barium nitrate?
............................................................................................................................................... [1]
[Total: 18]
© UCLES 2019 0620/51/M/J/19

5

6
2 You are provided with two substances, solution F and solid G.

Do the following tests on the substances, recording all of your observations at each stage.
tests on solution F

Divide solution F into five approximately equal portions in five test-tubes.
(a) Test the pH of the first portion of solution F.
pH = .............................. [1]
(b) Add a strip of magnesium ribbon to the second portion of solution F. Shake the mixture. Test
the gas produced.
.....................................................................................................................................................
............................................................................................................................................... [2]
(c) Add a few drops of dilute nitric acid and about 1 cm3 of aqueous silver nitrate to the third portion
of solution F.
............................................................................................................................................... [1]
(d) Add a few drops of dilute nitric acid and about 1 cm3 of aqueous barium nitrate to the fourth
portion of solution F.
............................................................................................................................................... [1]
Keep the fifth portion of the solution F for the test in (f).

© UCLES 2019 0620/51/M/J/19

7
tests on solid G

(e) Describe the appearance of solid G.
............................................................................................................................................... [1]
(f) Add the fifth portion of solution F to solid G. Test the gas produced.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
Add about 2 cm3 of distilled water to the solution formed in the test in (f) and shake the mixture.
Divide the solution formed into two approximately equal portions in two test-tubes for the tests in
(g) and (h).
(g) Add aqueous sodium hydroxide to the first portion of the solution until no further change occurs.
............................................................................................................................................... [2]
(h) Add an excess of aqueous ammonia to the second portion of the solution.
............................................................................................................................................... [1]
(i) Identify solution F.
............................................................................................................................................... [2]
(j) Identify solid G.
............................................................................................................................................... [2]
[Total: 16]

8
3 Steel nails rust in the presence of air and water. Plan an investigation to:
●● s how that coating steel nails with paint helps to protect the nails from rusting
●● show that coating steel nails with zinc helps to protect the nails from rusting
●● determine which coating is more effective at protecting steel nails from rusting.
You are provided with:
●● ncoated steel nails

u
●● steel nails coated with paint
●● steel nails coated with zinc
●● common laboratory apparatus.
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
...................................................................................................................................................... [6]
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9
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10
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11

Tests for anions

produced


colourless solution
© UCLES 2019 0620/51/M/J/19

12
gas test and test result metal ion flame colour

© UCLES 2019 0620/51/M/J/19

CHEMISTRY 0620/51
Paper 5 Practical test May/June 2019
MARK SCHEME
Maximum Mark: 40
Published
Teachers.

PUBLISHED
marking principles.
descriptors.

PUBLISHED

PUBLISHED
1(a) table of results
volumes of aqueous sodium carbonate boxes completed correctly 1, 2, 4, 5, 6, 7 1
heights of solid boxes completed 1
in mm 1
generally in ascending order 1
1(b) all points plotted correctly 1
appropriate scale for y-axis 1
best fit line drawn 1
1(c) value from graph 1
shown clearly 1
unit = mm 1
1(d) height increases 1
1(e) improvement:
use burette or pipette to measure the barium nitrate / leave to settle longer / use measuring cylinders instead of test- 1
tubes
explanation:
instead of measuring cylinder / solid more compact / easier to read 1

PUBLISHED
1(f) M1 filter 1
M2 dry 1
M3 weigh solid 1
1(g) repeat and take average/compare 1
1(h) precipitation 1

PUBLISHED
tests on solution F
2(a) 0-3 1
2(b) bubbles / fizz / effervescence 1
lighted splint pops 1
2(c) white precipitate 1
2(d) No reaction/change 1
tests on solid G
2(e) white (solid) 1
2(f) bubbles / fizz / effervescence 1
limewater 1
turns milky 1
2(g) white precipitate 1
remains / insoluble 1
2(h) no precipitate / no observation / reaction / change 1
2(i) hydrochloric 1
acid 1
2(j) calcium 1
carbonate 1

PUBLISHED
3 any six from: Max 6
• weigh nails / use set number of nails
• place nails in a suitable container
• add water to nails
• leave in water for a suitable time (≥ 1 week)
• observe nails / compare / reweigh nails
• repeat with nail with other coverings
• nail with least rust / mass increase has best coating

*3940113605*
CHEMISTRY 0620/61
1 hour

IB19 06_0620_61/3RP
2
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© UCLES 2019 0620/61/M/J/19

3
1 The diagram shows the apparatus a student used to prepare a dry sample of chlorine gas. Chlorine
is more dense than air.
concentrated ..........................................
hydrochloric
acid
..........................................
manganese(IV) oxide
flask 1 concentrated
sulfuric acid
(b) Use the diagram to identify two mistakes the student made.
1 ..................................................................................................................................................
.....................................................................................................................................................
2 ..................................................................................................................................................
.....................................................................................................................................................
[2]
(c) Suggest one reason why the gas produced in flask 1 is passed through concentrated
sulfuric acid.
............................................................................................................................................... [1]
(d) Describe a test for chlorine.
test ..............................................................................................................................................
observations ...............................................................................................................................
[2]
(e) Suggest why this experiment is done in a fume cupboard.
............................................................................................................................................... [1]
[Total: 8]

4
2 A student investigated the reaction between aqueous sodium carbonate and aqueous barium nitrate.
●● burette was filled with aqueous sodium carbonate.

A
●● Seven test-tubes were labelled 1, 2, 3, 4, 5, 6 and 7.
●● A measuring cylinder was used to pour 6 cm3 of aqueous barium nitrate into each of the seven
test‑tubes in a test‑tube rack.
●● 1.0 cm3 of aqueous sodium carbonate was added from the burette to test-tube 1.
A glass rod was used to stir the contents of each of the test‑tubes. The contents of the test‑tubes
were left to stand until the solid formed had settled. A ruler was used to measure the height of the
solid formed in each test‑tube.
(a) Use a ruler to measure the heights of the solid formed in each test‑tube shown in the diagram.
Record the heights of the solid formed in the table and complete the table.
test-tube number 1 2 3 4 5 6 7
volume of aqueous
sodium carbonate / cm3
solid
[3]
© UCLES 2019 0620/61/M/J/19

5
(b) Plot the results on the grid. Draw two intersecting lines of best fit. Label the x-axis.
100
80
60
height of
solid / mm
40
20
0
0 1 2 3 4 5 6 7 8
[4]
(c)
From your graph, deduce the height of the solid formed when 3.0
cm3 of aqueous
sodium carbonate is added to 6 cm of aqueous barium nitrate.
3
.............................. mm [2]
(d) Describe the trend in the heights of the solids formed in test‑tubes 1–7.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]

6
(e) Predict what would happen if the experiment were continued using three further test‑tubes
each containing 6 cm3 of aqueous barium nitrate and separately adding 9.0 cm3, 10.0 cm3 and
11.0 cm3 of aqueous sodium carbonate to each one.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
(f)
Suggest one change to the apparatus used which could be made to obtain more accurate
results.
............................................................................................................................................... [1]
(g) Suggest a different method to measure the amount of solid formed during the experiment.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
(h) Suggest how the reliability of the results could be checked.
.....................................................................................................................................................
............................................................................................................................................... [1]
[Total: 18]
© UCLES 2019 0620/61/M/J/19

7
3 Two substances, solution F and solid G, were analysed. Solution F was dilute hydrochloric acid.
Tests were done on solution F and solid G.
tests on solution F
Solution F was divided into four equal portions in four test‑tubes.
(a) The pH of the first portion of solution F was tested.
pH = .............................. [1]
(b) Magnesium ribbon was added to the second portion of solution F. The gas produced was
tested.
observations ...............................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
(c) Dilute nitric acid and aqueous silver nitrate were added to the third portion of solution F.
observations ......................................................................................................................... [1]
(d) Dilute nitric acid and aqueous barium nitrate were added to the fourth portion of solution F.
observations ......................................................................................................................... [1]

8
tests on solid G
tests on solid G observations
The appearance of solid G was studied. white solid
test 1
Dilute hydrochloric acid was added to solid G. rapid effervescence

The gas produced was tested. limewater turned milky
The solution formed was divided into two portions

for test 2.
test 2
An excess of aqueous sodium hydroxide was white precipitate formed which

added to the first portion of the solution from test 1. was insoluble in excess
An excess of aqueous ammonia was added to the no precipitate formed

second portion of the solution from test 1.
(e) Identify solid G.
............................................................................................................................................... [2]
[Total: 8]
© UCLES 2019 0620/61/M/J/19

9
4 Steel nails rust in the presence of air and water. Plan an investigation to:
●● s how that coating steel nails with paint helps to protect the nails from rusting
●● show that coating steel nails with zinc helps to protect the nails from rusting
●● determine which coating is more effective at protecting steel nails from rusting.
You are provided with:
●● ncoated steel nails

u
●● steel nails coated with paint
●● steel nails coated with zinc
●● common laboratory apparatus.
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
...................................................................................................................................................... [6]

10
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© UCLES 2019 0620/61/M/J/19

11
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© UCLES 2019 0620/61/M/J/19

12
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© UCLES 2019 0620/61/M/J/19

CHEMISTRY 0620/61
MARK SCHEME
Maximum Mark: 40
Published
Teachers.

PUBLISHED
marking principles.
descriptors.

PUBLISHED

PUBLISHED
1(a) (conical) flask (1) 2
gas jar (1)
1(b) no bung in second flask (1) 2
gas jar should not be inverted (1)
1(c) to dry the gas / remove water 1
1(d) litmus (1) 2
turns white/bleaches (1)
1(e) chlorine / gas is poisonous / toxic 1

PUBLISHED
volumes of aqueous sodium carbonate boxes completed correctly 1, 2, 4, 5, 6, 7, 8 (1) 3
heights of solid boxes completed 12, 24, 48, 60, 73, 73, 73 (1)
in mm (1)
2(b) x-axis labelled as “volume of aqueous sodium carbonate / cm3 (1) 4
all 7 points plotted correctly (2)
two intersecting straight line graphs drawn with a ruler (1)
2(c) working shown on graph in correct place (1) 2
value from graph (1)
2(d) height increases / proportional to volume / more solid (1) 2
level off / becomes constant (1)
2(e) same heights / at 73 mm (1) 2
all barium nitrate reacted (1)
2(f) use burette / pipette to measure out aqueous barium nitrate / instead of measuring cylinder 1
2(g) filter (1) 3
dry (1)
weigh solid (1)
2(h) repeat and compare 1

PUBLISHED
Tests on solution F
3(a) 0–3 1
3(b) bubbles / fizz / effervescence (1) 3
lighted splint / flame (1)
pops (1)
3(c) white precipitate 1
3(d) no reaction/change 1
Tests on solid G
3(e) calcium (1) 2
carbonate (1)

PUBLISHED
4 any six from: Max 6

• weigh nails / use set number of nails
• place nails in a suitable container
• add water to nails
• leave in water for a suitable time (≥ 1 week)
• observe nails / compare / reweigh nails
• repeat with nail with other coverings
• nail with least rust / mass increase has best coating

CHEMISTRY 0620/11
45 minutes
Soft clean eraser
*5634656915*

This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level1/Level 2 Certificate.
IB19 11_0620_11/3RP
2
1 The diagram shows a cup of hot tea.
A
B
C
D
2 A student is asked to measure the time taken for 0.4 g of magnesium carbonate to react
completely with 25.0 cm3 of dilute hydrochloric acid.
Which pieces of apparatus does the student need?
A balance, stop-clock, pipette

B balance, stop-clock, thermometer
D stop-clock, pipette, thermometer
3 A fractionating column is used to separate the hydrocarbon fractions in petroleum by fractional

distillation.
Which row describes the properties of the fractions that condense at the top of the fractionating
column?
size of molecule boiling point
A large high
B large low
C small high
D small low
© UCLES 2019 0620/11/O/N/19

3
4 Some information about solid silver chloride and solid sodium chloride is shown.
● Silver chloride and sodium chloride do not dissolve in kerosene.

● Silver chloride is insoluble in water but sodium chloride is soluble in water.
● The boiling point of silver chloride is 1547 °C and the boiling point of sodium chloride
is 1413 °C.
Which processes are used to separate a mixture of solid silver chloride and solid sodium
chloride?
A Add kerosene, stir and then filter.

B Add water, stir and then filter.
C Add water, stir and then leave to crystallise.
D Add water, stir and then perform fractional distillation.
5 A covalent molecule M contains four shared pairs of electrons.
What is M?
A ammonia, NH3
B hydrogen chloride, HCl
C methane, CH4
D water, H2O
52
6 An isotope of chromium is represented by 24 Cr .
Which statement about an atom of this isotope of chromium is correct?
A It contains 24 electrons.
B It contains 24 neutrons.
C It contains 28 protons.
D It contains 52 neutrons.

4
7 Substances P and Q both conduct electricity.
P is a mixture of two different types of atom.
Q is made of only one type of atom.
Which row describes P and Q?
P Q
A alloy element
B alloy compound
C compound alloy
D compound element
8 Graphite is a form of carbon.
Why can graphite be used as a lubricant?
A Graphite contains unbonded electrons which move through the structure.

B Graphite contains weak covalent bonds so the atoms move easily.
C Graphite has a low melting point so it easily turns into a liquid.
D Graphite has weak attractive forces between layers so they can move.
9 The structure of a molecule is shown.
H H H H
H C C O C C H
H H H H
What is the formula of the molecule?
A CHO B C2H5O C C4H8O D C4H10O
10 During the electrolysis of concentrated hydrochloric acid, gases are produced at both electrodes.
Which statement describes the test result for the gas collected at the negative electrode?
A It bleaches damp litmus paper.

B It burns with a ‘pop’.
C It relights a glowing splint.
D It turns limewater milky.
© UCLES 2019 0620/11/O/N/19

5
11 Which statements about endothermic reactions are correct?
1 The energy of the products is greater than the energy of the reactants.
2 The energy of the reactants is greater than the energy of the products.
3 The temperature of the surroundings increases during the reaction.
4 The temperature of the surroundings decreases during the reaction.
A 1 and 3 only B 1 and 4 only C 2 and 3 only D 2 and 4 only
12 Equations for the formation of anhydrous cobalt(II) chloride and anhydrous copper(II) sulfate are
shown.
CoCl 2•6H2O → CoCl 2 + 6H2O
CuSO4•5H2O → CuSO4 + 5H2O
Which statement about the reactions is not correct?
A Both reactions are exothermic.

B Both reactions are reversible.
C Hydrated cobalt(II) chloride changes colour from pink to blue.
D Hydrated copper(II) sulfate changes colour from blue to white.
13 A method used to investigate the rate of reaction of calcium carbonate with dilute hydrochloric
acid under different conditions is shown.
● Place 50 cm3 of dilute hydrochloric acid in a conical flask.

● Add a known volume of water to the conical flask.
● Heat the conical flask to the required temperature.
● Add 1.0 g of calcium carbonate to the conical flask.
● Measure the time taken for the reaction to finish.
Which volume of water and which temperature gives the shortest time taken for the reaction to
finish?
volume of water temperature

added / cm3 / °C
A 10 30
B 10 50
C 40 30
D 40 50

6
14 Which is a chemical change?
A boiling water
B cooking an egg
C dissolving sugar
D melting ice cubes
15 Mercury(II) oxide, HgO, decomposes when heated.
2HgO → 2Hg + O2
Why is this a reduction reaction?
A The products weigh less than the reactants.

B There are fewer reactants than products.
C There is a gain of oxygen.
D There is a loss of oxygen.
16 Carbonic acid is a weak acid formed when carbon dioxide dissolves in water.
What is the pH of the solution?
A 1 B 5 C 7 D 9
17 Solid X is tested as shown.
reaction with dilute

reaction with dilute
aqueous sodium flame test
hydrochloric acid
hydroxide
gas produced which

no reaction red flame
What is X?
A copper(II) carbonate
B lithium carbonate
C potassium carbonate
D sodium sulfate
© UCLES 2019 0620/11/O/N/19

7
18 Which oxide is basic?
A carbon dioxide
B sodium oxide
C sulfur dioxide
D water

2 Warm the acid.

step 3 step 4
B to ensure all of the acid has reacted to remove the excess of copper(II) oxide
D to speed up the reaction to remove the excess of copper(II) oxide
20 Which set of elements shows the change from metallic to non-metallic character across a period
of the Periodic Table?
A beryllium → magnesium → calcium
B fluorine → bromine → iodine
C oxygen → boron → lithium
D sodium → silicon → chlorine
21 Which pair of elements reacts together most violently?
A chlorine and lithium

B chlorine and potassium
C iodine and lithium
D iodine and potassium

8
22 What is not a typical property of a transition element?
A acts as a catalyst
B forms coloured compounds
C has a high melting point
D has a low density
Which element is used to provide an inert atmosphere?
A
B
C
D
24 Some properties of substance X are listed.
● It conducts electricity when molten.

● It has a high melting point.
● It burns in oxygen and the oxide dissolves in water to give a solution with pH 11.
What is X?
A a covalent compound
B a macromolecule
C a metal
D an ionic compound
© UCLES 2019 0620/11/O/N/19

9
25 Four different metals are reacted with an equal volume of dilute hydrochloric acid. The results of
the reactions are shown.
rate of
metal
effervescence
calcium very high
copper none
iron low
magnesium high
What is the order of reactivity of the four metals starting with the most reactive?
A iron → magnesium → calcium → copper
B magnesium → calcium → copper → iron
C copper → iron → magnesium → calcium
D calcium → magnesium → iron → copper
26 Iron is extracted from its ore in a blast furnace.
The equations for four different reactions are shown.
1 4Fe + 3CO2 → 2Fe2O3 + 3C
2 CO2 → C + O2
3 CO2 + C → 2CO
4 Fe2O3 + 3CO → 2Fe + 3CO2
Which equations represent reactions that occur in the blast furnace?
A Aluminium is used in the manufacture of aircraft because it has a high density.

B Copper is used for cooking utensils because it is a good conductor of heat.
C Mild steel is used for car bodies because it is resistant to corrosion.
D Stainless steel is used for cutlery because it is a conductor of electricity.

10
28 River water contains soluble impurities, insoluble impurities and bacteria.
River water is made safe to drink by filtration and chlorination.
A Filtration removes bacteria and insoluble impurities, and chlorination removes soluble
impurities.
B Filtration removes insoluble impurities, and chlorination kills the bacteria.
C Filtration removes soluble and insoluble impurities, and chlorination kills the bacteria.
D Filtration removes soluble impurities and bacteria, and chlorination removes insoluble
impurities.
29 Clean, dry air contains nitrogen, oxygen and small amounts of other gases. The noble gases
have been left out of the table.
Which row shows the composition of clean, dry air?
nitrogen / % oxygen / % other gases
A 21 78 small amount of carbon dioxide

B 21 78 small amount of carbon monoxide
C 78 21 small amount of carbon dioxide
D 78 21 small amount of carbon monoxide
© UCLES 2019 0620/11/O/N/19

11
damp iron wool
air
water
A B C D
31 Farmers add calcium oxide (lime) and ammonium salts to their fields.
The compounds are not added at the same time because they react with each other.
Which gas is produced in this reaction?
A ammonia
B carbon dioxide
C hydrogen
D nitrogen


12
33 What is not a use of sulfur dioxide?
A as a bleach
B as a food preservative
C in the manufacture of wood pulp for paper
D treating acidic soils
34 Which process is used to obtain lime from limestone?
A cracking
C neutralisation
35 Petroleum is separated by fractional distillation.
Which statement about the fractions produced is correct?
A Bottled gas for heating and cooking is obtained from the naphtha fraction.
B Diesel oil is used as a fuel for jet aircraft.
C Substances used to make polishes are obtained from the lubricating fraction.
D The kerosene fraction contains many useful waxes.
36 Which compounds have similar chemical properties?
A butanol and butanoic acid

B ethane and ethene
C methane and butane
D propene and propanol
37 Which statement about a molecule of ethane is correct?
A An ethane molecule has at least one double covalent bond.

B It has C–H and C–O bonds.
C An ethane molecule has seven covalent bonds.
D Its bonds are formed by the transfer of electrons.
© UCLES 2019 0620/11/O/N/19

13
38 Which products are obtained by the cracking of an alkane?
alkene hydrogen water
A
B
C
D
1 It has a pH value of 10.

2 It reacts with metal carbonates to produce carbon dioxide gas.
3 It reacts with magnesium metal to produce hydrogen gas.
40 The diagram shows the structure of a monomer and of the polymer made from it.
H H H H
n C C C C
H H H H
n
What are the monomer and polymer?
monomer polymer
© UCLES 2019 0620/11/O/N/19

14
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15
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© UCLES 2019 0620/11/O/N/19

Group
© UCLES 2019
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/11/O/N/19
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/11
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.
Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level
components.

PUBLISHED 2019
1 A 1
2 A 1
3 D 1
4 B 1
5 C 1
6 A 1
7 A 1
8 D 1
9 D 1
10 B 1
11 B 1
12 A 1
13 B 1
14 B 1
15 D 1
16 B 1
17 B 1
18 B 1
19 B 1
20 D 1
21 B 1
22 D 1
23 C 1
24 C 1
25 D 1
26 D 1
27 B 1
28 B 1

PUBLISHED 2019
29 C 1
30 B 1
31 A 1
32 B 1
33 D 1
34 D 1
35 C 1
36 C 1
37 C 1
38 B 1
39 D 1
40 D 1

CHEMISTRY 0620/21
45 minutes
Soft clean eraser
*8533346900*

IB19 11_0620_21/3RP
2
1 Samples of four gases are released in a room at the same time.
The gases are carbon dioxide, CO2, hydrogen chloride, HCl, hydrogen sulfide, H2S, and nitrogen
dioxide, NO2.
Which gas diffuses fastest?
A carbon dioxide
B hydrogen chloride
C hydrogen sulfide
D nitrogen dioxide
2 A student is asked to measure the time taken for 0.4 g of magnesium carbonate to react
completely with 25.0 cm3 of dilute hydrochloric acid.
Which pieces of apparatus does the student need?
A balance, stop-clock, pipette

B balance, stop-clock, thermometer
D stop-clock, pipette, thermometer
3 Four different food colourings are analysed using chromatography.
The results are shown on the chromatogram. The diagram is not drawn to scale.
Which food colouring contains a component with an Rf value of 0.3?
solvent front
10 cm
8 cm
6 cm
4 cm
2 cm
baseline
A B C D
© UCLES 2019 0620/21/O/N/19

3
4 Which statement about an ionic compound is not correct?
A It conducts electricity when dissolved in water.

B It has a high melting point due to strong attractive forces between ions.
C It has a regular lattice of oppositely charged ions in a ‘sea of electrons’.
D The ionic bonds are formed between metallic and non-metallic elements.
52
5 An isotope of chromium is represented by 24 Cr .
Which statement about an atom of this isotope of chromium is correct?
A It contains 24 electrons.
B It contains 24 neutrons.
C It contains 28 protons.
D It contains 52 neutrons.
12 14
6 Element X has two isotopes, 6X and 6X.
Which statement about these isotopes is correct?
A They have different chemical properties because they have different numbers of neutrons.
B They have the same chemical properties because they have the same number of outer shell
electrons.
C They have the same nucleon number because the sum of the number of protons and
electrons is the same.
D They have different positions in the Periodic Table because they have different numbers of
neutrons.
7 How are the structures of diamond and silicon(IV) oxide similar?
A Molecules of both diamond and silicon(IV) oxide are held together by weak attractive forces.
B They both contain atoms arranged in planes held together by weak bonds.
C They both contain ions that are free to move.
D The carbon in diamond and the silicon in silicon(IV) oxide each have four covalent bonds.
8 Which statement describes the structure of copper?
A It has a lattice of negative ions in a ‘sea of electrons’.

B It has a lattice of negative ions in a ‘sea of protons’.
C It has a lattice of positive ions in a ‘sea of electrons’.
D It has a lattice of positive ions in a ‘sea of protons’.

4
9 Four fertilisers are each supplied in 100 kg bags.
Which fertiliser supplies the greatest mass of nitrogen per 100 kg bag?
A ammonium nitrate, NH4NO3

B ammonium phosphate, (NH4)3PO4
C ammonium sulfate, (NH4)2SO4
D urea, CO(NH2)2
10 Calcium carbonate reacts with dilute hydrochloric acid.
The equation for the reaction is shown.
CaCO3 + 2HCl → CaCl 2 + H2O + CO2
1.00 g of calcium carbonate is added to 50.0 cm3 of 0.0500 mol / dm3 hydrochloric acid.
Which volume of carbon dioxide is made in this reaction?
A 30 cm3 B 60 cm3 C 120 cm3 D 240 cm3
11 Which rows correctly show cathode and anode products from the electrolysis of the named
electrolyte?
electrolyte cathode product anode product
1 copper(II) sulfate solution copper oxygen

using copper electrodes
2 molten lead(II) bromide lead bromine
3 dilute sodium bromide solution hydrogen oxygen
4 copper(II) sulfate solution hydrogen oxygen
using carbon electrodes
12 What are the ionic half-equations for the electrode reactions during the electrolysis of
concentrated aqueous sodium chloride?
anode cathode
A Cl 2 + 2e– → 2Cl – H2 → 2H+ + 2e–

B 2Cl – → Cl 2 + 2e– 2H+ + 2e– → H2
C H2 → 2H+ + 2e– Cl 2 + 2e– → 2Cl –
D 2H+ + 2e– → H2 2Cl – → Cl 2 + 2e–
© UCLES 2019 0620/21/O/N/19

5
13 Which statements about endothermic reactions are correct?
1 The energy of the products is greater than the energy of the reactants.
2 The energy of the reactants is greater than the energy of the products.
3 The temperature of the surroundings increases during the reaction.
4 The temperature of the surroundings decreases during the reaction.
14 Which gases are used to generate electricity in a fuel cell?

B hydrogen and methane
C hydrogen and oxygen
D methane and carbon dioxide
15 Which is a chemical change?
A boiling water
B cooking an egg
C dissolving sugar
D melting ice cubes
16 The rate of reaction between magnesium and dilute hydrochloric acid is increased by increasing
the concentration of the acid.
How does this affect the reacting particles?
proportion of particles with

collision rate of particles
sufficient energy to react
A increases increases
B increases stays the same
C stays the same increases
D stays the same stays the same

6
17 Dinitrogen tetroxide, N2O4, is converted into nitrogen dioxide, NO2, in a reversible reaction.
N2O4(g) 2NO2(g)
The forward reaction is endothermic.
Which conditions give the highest equilibrium yield of nitrogen dioxide?
pressure
temperature
/ atmospheres
A 2 high
B 2 low
C 50 high
D 50 low
18 The equation for the reaction between iron(II) sulfate and bromine is shown.
6FeSO4 + 3Br2 → 2Fe2(SO4)3 + 2FeBr3
Which row identifies the oxidising agent and the reducing agent?
oxidising agent reducing agent
A Br2 FeSO4
B FeSO4 Br2
C FeBr3 Fe2(SO4)3
D Fe2(SO4)3 FeBr3
19 Which statement about amphoteric oxides is correct?
A They are made by combining an acidic oxide with a basic oxide.

B They react with water to give a solution of pH 7.
C They react with both acids and bases.
D They do not react with acids or bases.
20 Carbonic acid is a weak acid formed when carbon dioxide dissolves in water.
What is the pH of the solution?
A 1 B 5 C 7 D 9
© UCLES 2019 0620/21/O/N/19

7

2 Warm the acid.

step 3 step 4
B to ensure all of the acid has reacted to remove the excess of copper(II) oxide
D to speed up the reaction to remove the excess of copper(II) oxide
22 Lead(II) sulfate is an insoluble salt.
Which process is not used to prepare a pure sample of this salt?
A crystallisation
B drying
C filtration
D precipitation
Which element is used to provide an inert atmosphere?
A
B
C
D

8
24 Which pair of elements reacts together most violently?
A chlorine and lithium

B chlorine and potassium
C iodine and lithium
D iodine and potassium
25 Which pair of compounds shows that transition elements have variable oxidation states?
A Cr2O3 and CrBr3

B CuSO4 and CuCl 2
C Fe2O3 and FeCl 2
D NiO and NiCl 2
26 Some properties of substance X are listed.
● It conducts electricity when molten.

● It has a high melting point.
● It burns in oxygen and the oxide dissolves in water to give a solution with pH 11.
What is X?
A a covalent compound
B a macromolecule
C a metal
D an ionic compound
A Aluminium is used in the manufacture of aircraft because it has a high density.

B Copper is used for cooking utensils because it is a good conductor of heat.
C Mild steel is used for car bodies because it is resistant to corrosion.
D Stainless steel is used for cutlery because it is a conductor of electricity.
© UCLES 2019 0620/21/O/N/19

9
28 Iron rusts but aluminium does not easily corrode.
Which statement explains why aluminium does not easily corrode?
A It is an alloy.
B It is below iron in the reactivity series.
C It is not a transition element.
D Its surface is protected by an oxide layer.
29 Which statement about the extraction of aluminium is correct?
A Aluminium is formed at the cathode during the electrolysis of aluminium oxide.

B Hematite is mainly aluminium oxide.
C Molten cryolite is used to raise the melting point of the aluminium oxide.
D Oxygen gains electrons at the anode during the electrolysis of aluminium oxide.
30 River water contains soluble impurities, insoluble impurities and bacteria.
River water is made safe to drink by filtration and chlorination.
A Filtration removes bacteria and insoluble impurities, and chlorination removes soluble
impurities.
B Filtration removes insoluble impurities, and chlorination kills the bacteria.
C Filtration removes soluble and insoluble impurities, and chlorination kills the bacteria.
D Filtration removes soluble impurities and bacteria, and chlorination removes insoluble
impurities.
31 Which physical property is used to separate the nitrogen and oxygen from air?
A boiling point
B density
C electrical conductivity
D molecular mass

10
damp iron wool
air
water
A B C D
33 Which statement about the carbon cycle is correct?
A Carbon is absorbed from the atmosphere by combustion and released into it by respiration.
B Carbon is absorbed from the atmosphere by photosynthesis and released into it by
combustion.
C Carbon is absorbed from the atmosphere by both respiration and combustion.
D Carbon is released into the atmosphere by both photosynthesis and respiration.
© UCLES 2019 0620/21/O/N/19

11
34 Ammonium sulfate is used as a fertiliser.
It is made from ammonia and sulfuric acid.
The ......1...... is made by the ......2...... process in which ......3...... is used as a catalyst.
1 2 3
A ammonia Contact iron

B ammonia Haber vanadium(V) oxide
C sulfuric acid Contact vanadium(V) oxide
D sulfuric acid Haber iron
35 Which process is used to obtain lime from limestone?
A cracking
C neutralisation
36 Petroleum is separated by fractional distillation.
Which statement about the fractions produced is correct?
A Bottled gas for heating and cooking is obtained from the naphtha fraction.
B Diesel oil is used as a fuel for jet aircraft.
C Substances used to make polishes are obtained from the lubricating fraction.
D The kerosene fraction contains many useful waxes.
37 Which products are obtained by the cracking of an alkane?
alkene hydrogen water
A
B
C
D

12
38 Ethanol is manufactured by the catalytic addition of steam to ethene and by fermentation.
Which statement describes an advantage of fermentation compared to the catalytic addition of

steam to ethene?
A Fermentation is a more rapid reaction.

B Fermentation produces a purer product.
C Fermentation uses a higher temperature.
D Fermentation uses renewable resources.
39 The diagram shows the structure of a monomer and of the polymer made from it.
H H H H
n C C C C
H H H H
n
What are the monomer and polymer?
monomer polymer
40 Which polymers possess the same linkage?
A nylon and protein

B protein and starch
C starch and nylon
D nylon and Terylene
© UCLES 2019 0620/21/O/N/19

13
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© UCLES 2019 0620/21/O/N/19

14
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© UCLES 2019 0620/21/O/N/19

15
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© UCLES 2019 0620/21/O/N/19

Group
© UCLES 2019
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/21/O/N/19
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/21
MARK SCHEME
Maximum Mark: 40
Published
examination.
Teachers.
components.

PUBLISHED 2019
1 C 1
2 A 1
3 C 1
4 C 1
5 A 1
6 B 1
7 D 1
8 C 1
9 D 1
10 A 1
11 C 1
12 B 1
13 B 1
14 C 1
15 B 1
16 B 1
17 A 1
18 A 1
19 C 1
20 B 1
21 B 1
22 A 1
23 C 1
24 B 1
25 C 1
26 C 1
27 B 1
28 D 1

PUBLISHED 2019
29 A 1
30 B 1
31 A 1
32 B 1
33 B 1
34 C 1
35 D 1
36 C 1
37 B 1
38 D 1
39 D 1
40 A 1

*6072633725*
CHEMISTRY 0620/31
1 hour 15 minutes

IB19 11_0620_31/3RP
2
1 This question is about solids, liquids and gases.
(a) The list gives the names of nine substances which are solids at room temperature.
a ceramic
aluminium
anhydrous cobalt(II) chloride
anhydrous copper(II) sulfate
calcium oxide
graphite
iodine
iron
sodium

State which substance:
(i) turns pink when water is added to it
........................................................................................................................................ [1]
(ii) is a non-metal which is used as a lubricant
........................................................................................................................................ [1]
(iii) is used to neutralise acidic industrial waste
........................................................................................................................................ [1]
(iv) is extracted from bauxite
........................................................................................................................................ [1]
(v) is used as an electrical insulator.
........................................................................................................................................ [1]
© UCLES 2019 0620/31/O/N/19

3
(b) Some changes of state of sodium are shown.
A evaporation
solid liquid sodium
sodium sodium gas
freezing B
(i) State the names of the changes of state represented by A and B.
A ..........................................................................................................................................
B ..........................................................................................................................................
[2]
(ii) Use the kinetic particle model to describe the arrangement and separation of the particles
in:
solid sodium .........................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
liquid sodium. .......................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
[4]
[Total: 11]

4
2 Biogas is made by fermenting animal and vegetable waste.
(a) The table shows the percentage composition of the gases present in a sample of biogas.
percentage
substance present
present in biogas
carbon dioxide 28.5
hydrogen 1.0
methane 62.0
nitrogen
water vapour 2.4
other substances 0.1
total 100.0
Deduce the percentage of nitrogen present in this sample of biogas.
............................................................................................................................................... [1]
(b) (i) Balance the chemical equation for the complete combustion of methane.
CH4 + .....O2 CO2 + .....H2O[2]
(ii) Which one of these compounds belongs to the same homologous series as methane?
methanoic acid methanol propane propanol propene[1]
(iii) M
ethane is present in the refinery gas fraction produced by the fractional distillation of
petroleum.
Match the fractions on the left with their uses on the right.
fraction use
refinery gas making roads
fuel oil fraction making chemicals
bitumen fuel for heating and cooking
naphtha fraction fuel for ships
[2]
© UCLES 2019 0620/31/O/N/19

5
(c) (i) Draw a dot-and-cross diagram to show the electron arrangement in a molecule of hydrogen.
[1]
(ii) State one use of hydrogen.
........................................................................................................................................ [1]
(d) The biogas contains a small amount of compound C.
The structure of compound C is shown.
H
H O
N C C
H O H
H C H
S
H
(i) On the structure shown, draw a circle around the carboxylic acid functional group. [1]
(ii) How many different types of atoms are present in compound C?
........................................................................................................................................ [1]
(e) Describe the manufacture of ethanol by fermentation.

In your answer include:
●● the names of the substances needed for fermentation

●● the conditions needed for fermentation.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [4]
[Total: 14]

6
3 A student investigated the reaction between zinc carbonate and an excess of dilute hydrochloric acid.
ZnCO3 + 2HCl ZnCl 2 + CO2 + H2O
The rate of reaction can be found by measuring the decrease in the mass of the reaction mixture
over time.
(a) Describe one other practical method for measuring the rate of this reaction.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
(b) When 6.25 g of zinc carbonate is used, 2.20 g of carbon dioxide is formed.
Calculate the mass of zinc carbonate that forms 11.00 g of carbon dioxide.
mass of zinc carbonate = .............................. g [1]
(c) What effect do the following have on the rate of this reaction?
●● Decreasing the temperature of the reaction mixture.

.....................................................................................................................................................
●● Increasing the concentration of hydrochloric acid.

.....................................................................................................................................................
[2]
(d) Carbon dioxide is formed:
●● hen an acid reacts with a carbonate

w
●● as a product of the complete combustion of carbon-containing substances.
State two other sources of carbon dioxide.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
[2]
[Total: 8]
© UCLES 2019 0620/31/O/N/19

7
4 An isotope of sodium is written as shown.
11Na
23
(a) (i) Deduce the number of protons, electrons and neutrons in this isotope of sodium.
number of protons ...............................................................................................................
number of electrons .............................................................................................................
number of neutrons .............................................................................................................

[3]
(ii) State one medical use of radioactive isotopes.
........................................................................................................................................ [1]
(b) (i) Draw the electronic structure of a sodium atom.
[2]
(ii) State the name of the particle which is lost when a sodium atom forms a sodium ion.
........................................................................................................................................ [1]

8
(c) Sodium reacts with water to form:
●● n alkaline solution
a
●● a gas which ‘pops’ with a lighted splint.
(i) Complete the word equation for the reaction of sodium with water.
.............................. ..............................
sodium + water +
..............................
[2]
(ii) The reaction of sodium with water is exothermic.
What is meant by the term exothermic?
..............................................................................................................................................
........................................................................................................................................ [1]
(iii) Sodium reacts with oxygen to form sodium oxide.
Is sodium oxide an acidic oxide or a basic oxide?

..............................................................................................................................................
........................................................................................................................................ [1]
(d) The table shows some observations for the reaction of four metals with cold water and with hot
water.
metal reaction with cold water reaction with hot water

calcium bubbles form rapidly bubbles form very rapidly
lanthanum bubbles form slowly bubbles form very rapidly
manganese no bubbles form bubbles form very slowly
uranium bubbles form slowly bubbles form rapidly
Use this information to put the four metals in order of their reactivity.
Put the least reactive metal first.
[2]
[Total: 13]
© UCLES 2019 0620/31/O/N/19

9
5 This question is about the halogens and compounds of the halogens.
(a) The properties of some halogens are shown in the table.
melting point boiling point density of liquid at its atomic radius

element
in °C in °C boiling point in g / cm3 in nm
chlorine –101 –35 0.099

........................
bromine –7 59 3.12 0.114
iodine 114 4.93 0.133

........................
astatine 302 337 6.35
(i) Complete the table to estimate:
●● the density of liquid chlorine

●● the boiling point of iodine.
[2]
(ii) Describe the trend in the atomic radius of the halogens down the group.
........................................................................................................................................ [1]
(iii) Predict the physical state of bromine at 50 °C.

..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(b) Bromine reacts with an aqueous potassium salt to form iodine and a different potassium salt.
Complete the word equation for this reaction.
.............................. ..............................
bromine + iodine +
.............................. ..............................
[2]

10
(c) Fluorine is above chlorine in Group VII of the Periodic Table.
(i) Explain, using ideas about the reactivity of the halogens, why chlorine does not react with
aqueous sodium fluoride.
..............................................................................................................................................
........................................................................................................................................ [1]
(ii) Balance the chemical equation for the reaction of fluorine with ammonia.
.....NH3 + .....F2 N2 + 6HF [2]
(iii) A compound of fluorine has the formula XeO3F2.
Complete the table to calculate the relative molecular mass of XeO3F2.

number relative
type of atom
of atoms atomic mass
xenon
oxygen 3 16 3 × 16 = 48
fluorine
relative molecular mass = ..............................

[2]
(iv) The compound XeO3F2 readily undergoes reduction.
What is meant by the term reduction?
........................................................................................................................................ [1]
[Total: 13]
© UCLES 2019 0620/31/O/N/19

11
6 This question is about ammonia.
(a) When ammonia gas reacts with hydrogen chloride gas, white fumes of ammonium chloride are
formed.
NH3 + HCl NH4Cl
(i) What type of chemical reaction is this?
decomposition neutralisation oxidation reduction[1]
(ii) Watch-glasses of aqueous ammonia and concentrated hydrochloric acid were placed near
each other on a table.
At first no white fumes were seen.
After a short time, white fumes were seen between the watch-glasses.
dense
white fumes
watch-glass watch-glass of
of ammonia hydrochloric acid
at the start a short time later
Explain these observations using the kinetic particle model.
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [3]
(b) Ammonia is used in the manufacture of fertilisers.
Name the three elements present in most fertilisers which improve plant growth.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
3 ..................................................................................................................................................
[3]

12
(c) Aqueous ammonia can be used to test for aluminium ions and zinc ions.
Complete the table to show the expected observations.
observation on adding a small observation on adding an

ion
volume of aqueous ammonia excess of aqueous ammonia
aluminium (Al 3+)
zinc (Zn2+)
[3]
[Total: 10]
© UCLES 2019 0620/31/O/N/19

13
7 (a) Magnesium is manufactured by the electrolysis of molten magnesium chloride.
(i) The negative electrode is made of iron.
Suggest a non-metal which could be used for the positive electrode.

..............................................................................................................................................
........................................................................................................................................ [2]
(ii) Predict the products of the electrolysis of molten magnesium chloride at:
the positive electrode ...........................................................................................................
the negative electrode. ........................................................................................................

[2]
(b)
The following statements are about the procedure for making crystals of hydrated
magnesium chloride from magnesium and dilute hydrochloric acid.
A Leave the mixture until no more bubbles are seen.

B Leave the mixture at room temperature to form more crystals.
C Add an excess of magnesium to dilute hydrochloric acid.
D Warm the filtrate to the point of crystallisation.
E Filter off the crystals and dry between filter papers.
F Filter off the excess magnesium.
Put the statements A, B, C, D, E and F in the correct order.

[2]
(c) Magnesium is a metal in Group II of the Periodic Table.

Copper is a transition element.
Copper has a higher melting point and a higher boiling point than magnesium.
Describe two other properties of copper which are different from those of magnesium.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
[2]

14
(d) Chromatography can be used to separate a mixture of ions from different transition element
compounds.
Four samples, R, S, T and U, each containing transition element ions, were placed on a piece
of chromatography paper.
Two solutions, Y and Z, each containing only one type of transition element ion were also
placed on the same piece of chromatography paper.
The results of the chromatography are shown.
R S T U Y Z
(i) Which sample, R, S, T or U, contains the same ions as both solution Y and solution Z?
........................................................................................................................................ [1]
(ii) Which sample, R, S, T or U, does not contain the same ions as either solution Y or
solution Z?
........................................................................................................................................ [1]
(iii) In which sample, R, S, T or U, has the greatest number of transition element ions been
separated?
........................................................................................................................................ [1]
[Total: 11]
© UCLES 2019 0620/31/O/N/19

15
BLANK PAGE
© UCLES 2019 0620/31/O/N/19

Group
© UCLES 2019
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/31/O/N/19
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/31
MARK SCHEME
Maximum Mark: 80
Published
Teachers.
components.

0620/31 Cambridge IGCSE – Mark Scheme October/November 2019
PUBLISHED
marking principles.
descriptors.

PUBLISHED

PUBLISHED
1(a)(i) (anhydrous) cobalt chloride 1
1(a)(ii) graphite 1
1(a)(iii) calcium oxide 1
1(a)(iv) aluminium 1
1(a)(v) ceramic 1
1(b)(i) A: melting (1) 2
B: condensing / condensation (1)
1(b)(ii) solid: 4
particles arranged regularly / particles ordered (1)
particles touching / particles close together (1)
liquid:
particles arranged irregularly / particles randomly arranged (1)
particles close together / particles touching (1)

PUBLISHED
2(a) 6.0 / 6 (%) 1
2(b)(i) 2 (O2) (1) 2
2 (H2O) (1)
2(b)(ii) propane 1
2(b)(iii) 3 correct (2) 2

1 or 2 correct (1)
fuel oil → fuel for ships

bitumen → making roads
naphtha → making chemicals
2(c)(i) two (hydrogen) atoms with pair of electrons between and no other electrons 1
2(c)(ii) fuel 1
2(d)(i) circle around the COOH group only 1
2(d)(ii) 5 1
2(e) glucose / sugar (1) 4
yeast (1)
AND
1 mark each for any two of:

• oxygen absent / anaerobic
• room temperature / stated temperature between 5 °C and 40 °C (inclusive)
• pH near neutral
• presence of water / aqueous solution
• purify by distillation

PUBLISHED
3(a) measuring volume of carbon dioxide (1) 3
use of gas measuring apparatus e.g. syringe / inverted measuring cylinder full of water (1)
(measure gas volume) at time intervals (1)
3(b) 31.25 (g) 1
3(c) decreases (rate) / slower (rate) (1) 2
increases (rate) faster (rate) (1)
3(d) (thermal) decomposition of carbonates (1) 2
respiration (1)

PUBLISHED
4(a)(i) protons: 11 (1) 3
electrons: 11 (1)
neutrons: 12 (1)
4(a)(ii) treating cancer / thyroid function / tracer for diagnosis 1
4(b)(i) electron in outer shell (1) 2
electrons in first shell AND eight electrons in the second shell (1)
4(b)(ii) electron 1
4(c)(i) sodium hydroxide (1) 2
hydrogen (1)
4(c)(ii) heat given out / heat evolved 1
4(c)(iii) basic (no mark alone) 1
AND
sodium is a metal (1)
4(d) manganese < uranium < lanthanum < calcium (2) 2
if 2 marks not scored allow 1 mark for 1 consecutive pair reversed

PUBLISHED
5(a)(i) density of chlorine: any value between 1 g / cm3 and 3 g / cm3 inclusive (1) 2
boiling point of iodine: any value between 115 °C and 320 °C inclusive (1)
5(a)(ii) increases (down the group) 1
5(a)(iii) liquid (1) 2
50 °C is between the melting point and boiling point / 50 °C is higher than the melting point but lower than the boiling point
(1)
5(b) potassium iodide (1) 2
potassium bromide (1)
5(c)(i) fluorine more reactive than chlorine ORA 1
5(c)(ii) 2 (NH3) (1) 2
3 (F2) (1)
5(c)(iii) 217 (2) 2
if 2 marks not scored 1 mark for F = 2 × 19 OR 38 (1)
5(c)(iv) removal of oxygen / addition of hydrogen / gain of electrons / decrease in oxidation number 1

PUBLISHED
6(a)(i) neutralisation 1
6(a)(ii) 1 mark each for any three of: 3

• evaporation / molecules escape from surface of the liquids
• diffusion
• molecules in (constant) movement / molecules collide
• (movement of) molecules is random / in every direction
• molecules spread out / molecules mix
• (molecules spread) from higher concentration to lower
• concentration
• molecules react (when they collide)
6(b) nitrogen (1) 3
phosphorus (1)
potassium (1)
6(c) 1 mark each for any three of: 3
white precipitate (1) (precipitate) does not dissolve / (precipitate) insoluble / white

precipitate remains (1)
white precipitate (1) (precipitate) dissolves / (precipitate) soluble (in excess) / colourless

solution (1)

PUBLISHED
7(a)(i) graphite (1) 2
conducts electricity / inert (1)
7(a)(ii) positive electrode: chlorine (1) 2
negative electrode: magnesium (1)
7(b) (C), A, F, D, B, E (2) 2

if 2 marks not scored 1 mark for 1 consecutive pair reversed
7(c) 1 mark each for any two of: 2

• high density ORA for Mg
• forms coloured compounds ORA for Mg
• forms ions with different charges / has variable oxidation number ORA for Mg
• forms complex ions ORA for Mg
• copper is catalyst ORA for Mg
• reference to difference in chemical properties e.g. magnesium reacts with dilute acid / copper does not react with dilute
acid
7(d)(i) R 1
7(d)(ii) T 1
7(d)(iii) R 1

*2338402729*
CHEMISTRY 0620/41
1 hour 15 minutes

IB19 11_0620_41/3RP
2
1 This question is about ions and ionic compounds.
(a) Choose from the following list of ions to answer the questions.
Br
–
Ca2+ Cl – Cr3+ Cu2+
K+ Li+ Na+ SO32– SO42–
Each ion may be used once, more than once or not at all.
State which ion:
(i) gives a lilac colour in a flame test .................................................................................. [1]
(ii) forms a grey-green precipitate with aqueous ammonia ................................................. [1]
(iii) forms a white precipitate with aqueous sodium hydroxide ............................................ [1]
(iv) forms a cream precipitate with acidified aqueous silver nitrate ..................................... [1]
(v) forms a white precipitate with acidified aqueous barium nitrate. ................................... [1]
(b) Describe how to do a flame test on a sample of a salt.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
(c) Magnesium phosphate contains magnesium ions, Mg2+, and phosphate ions, PO43–.
Deduce the formula of magnesium phosphate.
............................................................................................................................................... [1]
[Total: 8]
© UCLES 2019 0620/41/O/N/19

3
2 (a) Sulfur exists as a number of different isotopes.
What is meant by the term isotopes?
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
(b) A sulfide ion has the symbol shown.
34
16 S2–
(i) How many neutrons are contained in this sulfide ion?
........................................................................................................................................ [1]
(ii) How is a sulfide ion, S2–, formed from a sulfur atom?
........................................................................................................................................ [1]
(iii) Which element forms an ion with a 2+ charge that has the same number of electrons as
a S2– ion?
........................................................................................................................................ [1]

4
(c) The manufacture of sulfuric acid by the Contact process occurs in four stages.
stage 1 Molten sulfur is burned in air to produce sulfur dioxide gas.
stage 2 Sulfur dioxide is reacted with oxygen to form sulfur trioxide.
stage 3 Sulfur trioxide is combined with concentrated sulfuric acid to form oleum, H2S2O7.
stage 4 Oleum is added to water to form sulfuric acid.
(i) Complete the chemical equation for stage 1 by adding the appropriate state symbols.
S(.....) + O2(.....) SO2(.....)[1]
(ii) Name the catalyst used in stage 2 and state the temperature used.
catalyst .............................................
temperature ...................................... °C
[2]
(iii) Write chemical equations for the reactions in stage 3 and stage 4.
stage 3 ................................................................................................................................
stage 4 ................................................................................................................................
[2]
(d) Sulfur dioxide is a toxic gas.
(i) State one environmental reason why sulfur dioxide should not be released into the
atmosphere.
........................................................................................................................................ [1]
(ii) Describe the test for sulfur dioxide.
test .......................................................................................................................................
..............................................................................................................................................
observations ........................................................................................................................
..............................................................................................................................................
[2]
© UCLES 2019 0620/41/O/N/19

5
(e) S
ulfur dioxide reacts with aqueous sodium sulfite to produce a compound with the following
composition by mass: 29.1% Na, 40.5% S and 30.4% O.
Calculate the empirical formula of this compound.
empirical formula = .............................. [3]
[Total: 16]

6
3 This question is about metals and metal oxides.
(a) Most metals have a high melting point.
State one other physical property that all metals have.
............................................................................................................................................... [1]
(b) Iron often rusts.
Name the two substances, other than iron, that must be present for iron to rust.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
[1]
(c) Iron can be obtained by heating iron(III) oxide with zinc powder.
Fe2O3 + 3Zn 2Fe + 3ZnO
(i) What can be deduced about the reactivity of zinc from this reaction?
........................................................................................................................................ [1]
(ii) The ionic equation for this reaction is shown.
2Fe3+ + 3Zn 2Fe + 3Zn2+
Identify the oxidising agent in this reaction. Explain your answer in terms of electron
transfer.
oxidising agent .....................................................................................................................
explanation ..........................................................................................................................
..............................................................................................................................................
[2]
© UCLES 2019 0620/41/O/N/19

7
(d) Zinc oxide is amphoteric.
Describe two simple experiments to show that zinc oxide is amphoteric.

Name the reagents you would use and describe the observations you would make.
reagent 1 ....................................................................................................................................
observation .................................................................................................................................
reagent 2 ....................................................................................................................................
observation .................................................................................................................................
[3]
[Total: 8]

8
4 Insoluble salts can be made by precipitation reactions.
A student mixed solutions of some soluble salts.
The results the student obtained are shown in the table.
second salt solution

Co(NO3)2(aq) AgNO3(aq) Pb(NO3)2(aq)
NaI(aq) no change yellow precipitate yellow precipitate
first salt
Na2CO3(aq) purple precipitate yellow precipitate white precipitate
solution
Na2SO4(aq) no change white precipitate white precipitate
All sodium salts are soluble in water.

Use only results from the table to answer the following questions.
(a) Name:
(i) an insoluble cobalt salt .................................................................................................. [1]
(ii) an insoluble yellow lead salt. ......................................................................................... [1]
(b) Write the chemical equation for the reaction in which silver carbonate is formed.
............................................................................................................................................... [2]
(c) Write the ionic equation for the reaction in which lead(II) iodide is formed.
............................................................................................................................................... [2]
(d) Aqueous silver nitrate produces a yellow precipitate with both iodide ions and carbonate ions.
When testing an unknown solution for iodide ions, the aqueous silver nitrate is acidified.
Explain why the aqueous silver nitrate is acidified.
.....................................................................................................................................................
............................................................................................................................................... [1]
[Total: 7]
© UCLES 2019 0620/41/O/N/19

9
5 (a) Part of the structure of synthetic polymer A is shown.
CH3 CH3 CH3 CH3 CH3 CH3
C C C C C C
CH3 CH3 CH3 CH3 CH3 CH3
(i) What type of synthetic polymer is A?
........................................................................................................................................ [1]
(ii) Deduce the empirical formula of polymer A.
........................................................................................................................................ [1]
(iii) Draw the structure of the monomer from which polymer A is made.
[2]
(b) The formula C4H10 represents two different structural isomers.
(i) What is meant by the term structural isomers?
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) Draw the structures of two structural isomers with the formula C4H10.
[2]
(iii) All structural isomers of C4H10 are flammable.
Write a chemical equation for the incomplete combustion of C4H10.
........................................................................................................................................ [2]
[Total: 10]

10
6 Dilute hydrochloric acid, HCl (aq), reacts with aqueous sodium carbonate, Na2CO3(aq).
The chemical equation for the reaction is shown.
2HCl + Na2CO3 2NaCl + CO2 + H2O
(a) A 25.0 cm3 portion of Na2CO3(aq) was placed in a conical flask with a few drops of a suitable
indicator. It was titrated against HCl (aq) of concentration 0.180 mol /dm3.
20.0 cm3 of HCl (aq) was required to reach the end-point.
Calculate the concentration of the Na2CO3(aq), in mol / dm3, using the following steps.
●● Calculate the number of moles of HCl used in the titration.
.............................. mol
●● Calculate the number of moles of Na2CO3 contained in the 25.0 cm3 portion of Na2CO3(aq).
.............................. mol
●● Calculate the concentration of the Na2CO3(aq) in mol / dm3.
.............................. mol / dm3
[3]
(b) In another experiment, the volume of carbon dioxide, CO2, produced was 48.0 cm3, measured
at room temperature and pressure.
How many moles of CO2 is this?
moles of CO2 = .............................. mol [1]
© UCLES 2019 0620/41/O/N/19

11
(c)
A sample of concentrated hydrobromic acid, HBr(aq), was electrolysed using platinum
electrodes.
The concentration of the hydrobromic acid was 8.89 mol / dm3.
(i) Calculate the concentration of the HBr(aq) in g / dm3.
concentration of HBr(aq) = .............................. g / dm3 [1]
(ii) Explain why concentrated HBr(aq) can conduct electricity.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(iii) Magnesium is not a suitable material from which to make the electrodes.
Explain why.
..............................................................................................................................................
........................................................................................................................................ [1]
(iv) Predict the product formed at the anode when concentrated HBr(aq) is electrolysed.
........................................................................................................................................ [1]
(v) Write the ionic half-equation for the reaction occurring at the cathode.
........................................................................................................................................ [2]
[Total: 11]

12
7 This question is about ethanol.
(a) Ethanol that is suitable for use as a fuel can be manufactured from sugars such as glucose,
C6H12O6, by a two-step process.
Describe how this can be done. In your answer, include:
●● an equation for the reaction in which ethanol is formed

●● the essential conditions for the reaction in which ethanol is formed
●● the name of the process used to obtain ethanol that is pure enough to use as a fuel from
the reaction mixture.
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [5]
© UCLES 2019 0620/41/O/N/19

13
(b) The equation for the complete combustion of ethanol is shown.
H H
H C C O H + 3 O O 2 O C O + 3 H O H
H H
Use the bond energies in the table to calculate the energy change, in kJ / mol, for the complete
combustion of ethanol.
bond energy
bond
in kJ / mol
C–C 347
C–H 413
C–O 358
C=O 805
O–H 464
O=O 498
●● Energy needed to break bonds.
.............................. kJ
●● Energy released when bonds are formed.
.............................. kJ
●● Energy change for the complete combustion of ethanol.
energy change = .............................. kJ / mol

[3]

14
(c) Ethanol can be oxidised by hydrogen peroxide to form ethanal, CH3CHO. A catalyst for this
reaction is Fe3+.
(i) What is meant by the term catalyst ?
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) The structure of ethanal is shown.
H C C O
H H
Complete the dot-and-cross diagram to show the electron arrangement in a molecule of

ethanal. Show outer shell electrons only.
H C C O
H H
[3]
(iii) The table gives the boiling points of ethanal and ethanol.
substance boiling point / °C

ethanal 20
ethanol 78
In terms of attractive forces between particles, suggest why ethanal has a lower boiling
point than ethanol.
..............................................................................................................................................
........................................................................................................................................ [1]
© UCLES 2019 0620/41/O/N/19

15
(d) Ethene gas reacts with steam to form gaseous ethanol.
C2H4(g) + H2O(g) CH3CH2OH(g)
The reaction can reach a position of equilibrium. The forward reaction is exothermic.
(i) State and explain the effect of increasing the pressure on the position of equilibrium.
All other conditions are unchanged.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(ii) Increasing the pressure of a gas increases its concentration.
State and explain the effect of increasing the pressure on the rate of the reaction.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
(iii) State and explain the effect of increasing the temperature on the position of equilibrium.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [2]
[Total: 20]
© UCLES 2019 0620/41/O/N/19

Group
© UCLES 2019
1 2
H He
hydrogen helium
Key 1 4
11 12 13 14 15 16 17 18
23 24 27 28 31 32 35.5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
16
85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131
55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
0620/41/O/N/19
lanthanoids
133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – –
87 88 89–103 104 105 106 107 108 109 110 111 112 114 116
actinoids
– – – – – – – – – – – – –
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
139 140 141 144 – 150 152 157 159 163 165 167 169 173 175
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
– 232 231 238 – – – – – – – – – – –
CHEMISTRY 0620/41
MARK SCHEME
Maximum Mark: 80
Published
Teachers.
components.

PUBLISHED
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific
content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these marking
principles.
• answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question
as indicated by the mark scheme. The meaning, however, should be unambiguous.
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors.

PUBLISHED
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be
limited according to the quality of the candidate responses seen).
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade
descriptors in mind.

PUBLISHED
1(a)(i) K+ 1
1(a)(ii) Cr3+ 1
1(a)(iii) Ca2+ 1
1(a)(iv) Br- 1
1(a)(v) SO42- 1
1(b) (compound / salt) on wooden splint or (nichrome / platinum) wire (1) 2

into (roaring) Bunsen flame (1)
1(c) Mg3(PO4)2 1

PUBLISHED
2(a) atoms with same number of protons or atoms of the same element or atoms with same atomic number (1) 2
atoms with different number of neutrons or atoms with different mass number or atoms with different nucleon number (1)
2(b)(i) 18 1
2(b)(ii) gain of two electrons 1
2(b)(iii) Ca / calcium 1
2(c)(i) l ..g ..g. 1
2(c)(ii) vanadium (V) oxide or vanadium pentoxide (1) 2

450 (°C) (1)
2(c)(iii) SO3 + H2SO4 → H2S2O7 (1) 2

H2S2O7 + H2O → 2 H2SO4 (1)
2(d)(i) (it causes) acid rain 1
2(d)(ii) test – (aqueous) potassium manganate (VII) (1) 2

(purple to) colourless (1)
2(e) 29.1 / 23 40.5 / 32 30.4 / 16 or 1.2(65) 1.2(65) 1.9 (1) 3

1:1:1.5 (1)
Na2S2O3 (1)

PUBLISHED
3(a) malleable / conduct electricity / conduct heat 1
3(b) water and oxygen / air 1
3(c)(i) (zinc is) more reactive than iron 1
3(c)(ii) Fe3+ (1) 2

accept / take / gain electrons (1)
3(d) (add a) named acid (1) 3

(add a) named alkali (1)
disappears / dissolves in both (1)
4(a)(i) cobalt carbonate 1
4(a)(ii) lead iodide 1
4(b) 2 AgNO3 + Na2CO3 → Ag2CO3 + 2 NaNO3 2

formula of silver carbonate correct (1)
fully correct equation (1)
4(c) Pb2+ + 2 I– → PbI2 2

Pb2+ and I– on left of equation (1)
fully correct equation (1)
4(d) (nitric) acid reacts with / removes carbonate ions 1

PUBLISHED
5(a)(i) addition 1
5(a)(ii) CH2 1
5(a)(iii) 2
one C=C (1)

fully correct structure (1)
5(b)(i) (compounds / molecules with) the same molecular formula (1) 2

different structural formulae (1)
5(b)(ii) 2
(1)
(1)
5(b)(iii) H2O and CO or C formed (1) 2

2 C4H10 + 9 O2 → 8 CO + 10 H2O (1)

PUBLISHED
6(a) correct final answer = 0.072(0) 3
M1 moles HCl = 0.0036(0)

M2 moles Na2CO3 = 0.0018(0) (M1 / 2)
M3 concentration Na2CO3 = 0.072 (M2 / 0.025)
6(b) 0.002(00) 1
6(c)(i) 720(.09) 1
6(c)(ii) (it contains) ions (1) 2

(ions) are able to move (1)
6(c)(iii) magnesium is not inert 1
6(b)(iv) bromine / Br2 1
6(b)(v) H+ and e(–) on LHS (1) 2

fully correct, i.e.: 2H+ + 2e– → H2 (1)
7(a) C6H12O6 → 2CO2 + 2C2H5OH (1) 5
any three from

• anaerobic
• 30 °C
• yeast
• glucose aqueous
fractional distillation (of aqueous ethanol) (1)
7(b) (energy to break bonds) = 4728 (1) 3

(energy released by making bonds) = 6004 (1)
–1276 (1)

PUBLISHED
7(c)(i) speeds up a (chemical) reaction (1) 2

not used up or unchanged (at end) (1)
7(c)(ii) 4 electrons in double bond between C and O (1) 3

all single bonds correct (1)
C and O each have 8 electrons in outer shell, all H have 2 electrons in outer shell (1)
7(c)(iii) (attractive) forces between molecules weaker in ethanal 1
7(d)(i) moves right (1) 2

fewer moles / molecules (of gas) on right (1)
7(d)(ii) (reaction is faster) because more collisions per second (1) 2

particles / molecules closer together or more particles / molecules per unit volume (1)
7(d)(iii) moves left (1) 2

(forward) reaction is exothermic or backward reaction is endothermic (1)

CHEMISTRY 0620/51
*2835959356*
This document gives details of how to prepare for and administer the practical exam.
The information in this document and the identity of any materials supplied by Cambridge International
are confidential and must NOT reach candidates either directly or indirectly.
The supervisor must complete the report at the end of this document and return it with the scripts.
If you have any queries regarding these confidential instructions, contact Cambridge International stating the
centre number, the syllabus and component number and the nature of the query.
email info@cambridgeinternational.org
phone +44 1223 553554
fax +44 1223 553558
IB19 11_0620_51/CI/FP
2
General information about practical exams

Centres must follow the guidance on science practical exams given in the Cambridge Handbook.
Safety
Supervisors must follow national and local regulations relating to safety and first aid.
Only those procedures described in the question paper should be attempted.
Supervisors must inform candidates that materials and apparatus used in the exam should be treated
with caution. Suitable eye protection should be used where necessary.
The following hazard codes are used in these confidential instructions, where relevant:

Hazard data sheets relating to substances used in this exam should be available from your chemical
supplier.
Before the exam
● The packets containing the question papers must not be opened before the exam.
● It is assumed that standard school laboratory facilities, as indicated in the Guide to Planning
Practical Science, will be available.
● Spare materials and apparatus for the tasks set must be available for candidates, if required.
During the exam
● It must be made clear to candidates at the start of the exam that they may request spare materials
and apparatus for the tasks set.
● Where specified, the supervisor must perform the experiments and record the results as instructed.
This must be done out of sight of the candidates, using the same materials and apparatus as the
candidates.
● Any assistance provided to candidates must be recorded in the supervisor’s report.
● If any materials or apparatus need to be replaced, for example, in the event of breakage or loss,
this must be recorded in the supervisor’s report.
After the exam
● The supervisor must complete a report for each practical session held and each laboratory used.
● Each packet of scripts returned to Cambridge International must contain the following items:
● the scripts of the candidates specified on the barcode label provided

● the supervisor’s results relevant to these candidates
● the supervisor’s reports relevant to these candidates
● seating plans for each practical session, referring to each candidate by candidate number
● the attendance register.
© UCLES 2019 0620/51/CI/O/N/19

3
Specific information for this practical exam
concentrations.
● 100 cm3 of dilute hydrochloric acid of concentration 0.20 mol / dm3, labelled dilute

hydrochloric acid for Question 1
[MH] ● 50 cm3 of aqueous sodium hydroxide of concentration 0.10 mol / dm3, labelled

solution R
[MH] ● 50 cm3 of aqueous sodium hydroxide of concentration 0.20 mol / dm3, labelled

solution S
● 50 cm3 of aqueous sodium hydroxide of concentration 0.050 mol / dm3, labelled

solution T
● access to water and distilled water
[C][F][HH] ● methyl orange indicator

[MH][N][T]
● 25 cm3 or 50 cm3 measuring cylinder
● 250 cm3 conical flask
● 50 cm3 burette with stand and clamp
● white tile
● funnel for filling burette
● teat pipette

4
concentrations.
[MH] ● stoppered test‑tube containing about 0.5 g of

chromium(III) potassium sulfate‑12‑water (chrome alum), CrK(SO4)2•12H2O,
labelled solid U
[F][MH] ● stoppered test‑tube containing about 2 cm3 of hexane, labelled liquid V
[MH][N] ● a small crystal or small pellet of iodine in a stoppered test‑tube
● aqueous barium nitrate of suitable concentration to give a positive sulfate test
[C] ● dilute nitric acid of concentration 1.0 mol / dm3
[C] ● aqueous sodium hydroxide of concentration 1.0 mol / dm3
[MH][N] ● aqueous ammonia of concentration 1.0 mol / dm3
● distilled water
● splints
● apparatus for a flame test
● Bunsen burner and means to light it
● rack of test-tubes
● boiling tube
● stopper to fit boiling tube
● watch-glass
● teat pipettes
● spatula
© UCLES 2019 0620/51/CI/O/N/19

5
BLANK PAGE

6
BLANK PAGE
© UCLES 2019 0620/51/CI/O/N/19

7
Supervisor’s report
Syllabus and component number /
Centre number
Centre name ��
Time of the practical session ��
Laboratory name/number ��
Give details of any difficulties experienced by the centre or by candidates (include the relevant
candidate names and candidate numbers).
You must include:
● ny difficulties experienced by the centre in the preparation of materials

a
● any difficulties experienced by candidates, e.g. due to faulty materials or apparatus
● any specific assistance given to candidates.

8
Declaration
1 Each packet that I am returning to Cambridge International contains the following items:
the scripts of the candidates specified on the barcode label provided

the supervisor’s results relevant to these candidates
the supervisor’s reports relevant to these candidates
seating plans for each practical session, referring to each candidate by candidate number
the attendance register
2 Where the practical exam has taken place in more than one practical session, I have clearly
labelled the supervisor’s results, supervisor’s reports and seating plans with the time and laboratory
name/number for each practical session.
3 I have included details of difficulties relating to each practical session experienced by the centre or
by candidates.
4 I have reported any other adverse circumstances affecting candidates, e.g. illness, bereavement or
temporary injury, directly to Cambridge International on a special consideration form.
Signed ....................................................................................................... (supervisor)
Name (in block capitals) ............................................................................
© UCLES 2019 0620/51/CI/O/N/19

*9022804374*
CHEMISTRY 0620/51
1 hour 15 minutes

Total
IB19 11_0620_51/FP
2
1 You are going to investigate the reaction between dilute hydrochloric acid and three different
concentrations of aqueous sodium hydroxide, labelled R, S and T.

Instructions
You are going to do three experiments.

Experiment 1
●● ill the burette up to the 0.0 cm3 mark with dilute hydrochloric acid.

F
●● Use the measuring cylinder to pour 20 cm3 of solution R into the conical flask.
●● Add six drops of methyl orange indicator to the conical flask.
●● Add dilute hydrochloric acid from the burette to the conical flask, 1.0 cm3 at a time, while
swirling the conical flask, until the solution just changes colour.
●● Record the burette readings in the table.
●● Empty the conical flask and rinse it with distilled water.
Experiment 2
●● epeat Experiment 1 using solution S instead of solution R.

R

Experiment 3
●● epeat Experiment 1 using solution T instead of solution R.

R
(a) Complete the table.
Experiment 1 Experiment 2 Experiment 3

burette reading / cm3
using solution R using solution S using solution T
initial burette reading
volume used
[4]
(b)
What colour change is observed in the conical flask at the end-point?
from ................................................................ to ................................................................. [2]
(c) Suggest why Universal Indicator is not a suitable indicator to use in these experiments.
.....................................................................................................................................................
............................................................................................................................................... [1]
© UCLES 2019 0620/51/O/N/19

3
(d) (i) Complete the sentences.
Experiment ........ needed the smallest volume of dilute hydrochloric acid to change the
colour of the methyl orange indicator.
Experiment ........ needed the largest volume of dilute hydrochloric acid to change the
colour of the methyl orange indicator.
[1]
(ii) Determine the simplest whole number ratio of volumes of dilute hydrochloric acid used in
Experiments 1 and 2.
Experiment 1 ........ : ........ Experiment 2 [1]
(iii)
Deduce the order of concentrations of the solutions of aqueous sodium hydroxide,
R, S and T.
most concentrated .................................
.................................
least concentrated .................................

[1]
(e) What would be the effect on the results, if any, if the solutions of aqueous sodium hydroxide
were warmed before adding the dilute hydrochloric acid? Give a reason for your answer.
effect on the results ....................................................................................................................
reason .........................................................................................................................................
[2]
(f) Suggest how the reliability of the results could be checked.
.....................................................................................................................................................
............................................................................................................................................... [2]
(g) Suggest a different method, not involving an indicator, of finding the order of concentrations of
the solutions of aqueous sodium hydroxide, R, S and T.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [3]
[Total: 17]

4
2 You are provided with solid U and liquid V.

Do the following tests on solid U and liquid V, recording all of your observations at each stage.
tests on solid U

(a) Do a flame test on a small sample of solid U.

............................................................................................................................................... [1]
Add the rest of solid U to about 10 cm3 of distilled water in a boiling tube. Stopper the boiling tube
and shake the mixture to dissolve solid U and form solution U.
(b) Describe the colour of solution U.
............................................................................................................................................... [1]
Divide solution U into three approximately equal portions in three test‑tubes.
(c) (i) Add a few drops of aqueous sodium hydroxide to the first portion of solution U.
........................................................................................................................................ [1]
(ii) Now add an excess of aqueous sodium hydroxide to this mixture.

........................................................................................................................................ [1]
(d) (i) Add a few drops of aqueous ammonia to the second portion of solution U.
........................................................................................................................................ [2]
(ii) Now add an excess of aqueous ammonia to this mixture.

........................................................................................................................................ [1]
(e) Add a few drops of dilute nitric acid and about 1 cm3 of aqueous barium nitrate to the third
portion of solution U. Leave to stand for 5 minutes.
............................................................................................................................................... [2]
(f) Solid U contains three different ions.
What conclusions can you draw about the ions present in solid U?
.....................................................................................................................................................
............................................................................................................................................... [3]
© UCLES 2019 0620/51/O/N/19

5
tests on liquid V

(g) Describe the appearance of liquid V.

............................................................................................................................................... [1]
(h) Use a teat pipette to place a few drops of liquid V onto a watch‑glass. Put the stopper back into
the test‑tube of liquid V. Use a lighted splint to touch the surface of liquid V carefully.
............................................................................................................................................... [1]
(i) Use a spatula to transfer a small crystal of iodine carefully into the rest of liquid V in the
stoppered test‑tube. Put the stopper back into the test‑tube and shake the test‑tube.
.....................................................................................................................................................
............................................................................................................................................... [2]
(j) Draw one conclusion about liquid V.
............................................................................................................................................... [1]
[Total: 17]

6
3 Potassium nitrate and ammonium chloride are two salts. The energy change when they each
dissolve in water is endothermic.
Plan an experiment to show which of these two salts produces the larger endothermic energy
change per gram.
Your answer should include:

●● any measurements you would take and record
●● how the results could be used to draw a conclusion.
You are provided with potassium nitrate and ammonium chloride, distilled water and common
laboratory apparatus.
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
...................................................................................................................................................... [6]
© UCLES 2019 0620/51/O/N/19

7

Tests for anions

produced


colourless solution
© UCLES 2019 0620/51/O/N/19

8
gas test and test result metal ion flame colour

© UCLES 2019 0620/51/O/N/19

CHEMISTRY 0620/51
MARK SCHEME
Maximum Mark: 40
Published
Teachers.
components.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1 / Level 2 Certificate.

0620 / 51 Cambridge IGCSE – Mark Scheme October/November 2019
PUBLISHED
marking principles.
descriptors.

PUBLISHED

PUBLISHED
initial and final reading boxes completed correctly 1
differences completed correctly 1
all readings to 1 decimal place 1
comparable to supervisors 1
1(b) yellow 1
orange / pink / red 1
1(c) no sharp colour change / no (clear) end point 1
1(d)(i) (Experiment) 3 (needed smallest) 1

and
(Experiment) 2 (needed largest)
1(d)(ii) 1:2 1
1(d)(iii) most concentrated S 1

R
least concentrated T
1(e) no effect / none 1
concentration of reactants not affected / unchanged / same 1
1(f) repeat the experiment 1
compare results / to check for anomalous results / until concordant results owtte 1

PUBLISHED
1(g) MP1 measurement to be taken 3

MP2 use of results to draw conclusion
MP3 reactant / method
thermometric
• measure temperature (change)
• highest temperature (change) is most concentrated
• add (excess) hydrochloric acid
precipitation of metallic hydroxide

• measure mass / height of precipitate
• most precipitate is most concentrated
• add (xs aqueous) copper sulfate (for example)
gas produced
• measure volume of gas made
• largest volume is most concentrated
• add an ammonium salt or aluminium
evaporation
• mass of solid
• most mass is most concentrated
• evaporate solution
pH meter
• measure pH
• highest pH is most concentrated
• pH meter
dissolving
• measure time taken for solid to dissolve
• shortest time is most concentrated
• aluminium / aluminium oxide / zinc / zinc oxide

PUBLISHED
tests on solid U
2(a) lilac 1
2(b) blue / purple / violet 1
2(c)(i) green precipitate 1
2(c)(ii) green solution / precipitate dissolves 1
2(d)(i) grey-green 1
precipitate 1
2(d)(ii) insoluble / remains / no change 1
2(e) white 1
precipitate 1
2(f) potassium 1
chromium 1
sulfate 1
tests on liquid V
2(g) colourless 1
2(h) burns / ignites / yellow flame 1
2(i) pink / purple 1
solution / crystal dissolves / crystal smaller 1
2(j) fuel / organic 1

PUBLISHED
3 any six from: max 6

• known volume / amount of (distilled) water
• initial temperature (of water before solid is added)
• add measured mass / stated mass of potassium nitrate or ammonium chloride
• stir / mix / dissolve / swirl / shake
• final temperature of solution / temperature every 30 s
• repeat with (same mass of) other solid (and volume / amount of water) OR measured mass of other solid
• greater temperature change / decrease OR lowest final temperature is larger energy change / calculate energy
change per gram

*2909684625*
CHEMISTRY 0620/61
1 hour

IB19 11_0620_61/2RP
2
1 The apparatus shown was used to investigate the products formed when ethanol, C2H5OH, burns
in air.
to suction
pump
limewater
ethanol
ice U-tube water
(b) Explain why water collects in the U-tube.
.....................................................................................................................................................
............................................................................................................................................... [2]
(c) State a chemical test for water.
test ..............................................................................................................................................
observations ...............................................................................................................................
[2]
(d) What is the purpose of the suction pump?
.....................................................................................................................................................
............................................................................................................................................... [1]
(e) Predict the change seen in the test-tube containing the limewater. Explain your prediction.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
[Total: 8]
© UCLES 2019 0620/61/O/N/19

3
2
A student investigated the rate of reaction between dilute nitric acid and an excess of
solid magnesium carbonate at room temperature.
A small test‑tube containing magnesium carbonate was suspended in the conical flask.
inverted 250 cm3

measuring
cylinder
solid
magnesium
carbonate
water
dilute
nitric acid
50 cm3 of dilute nitric acid was added to the conical flask. The contents of the test‑tube were
released, allowing the solid magnesium carbonate to mix with the dilute nitric acid. A stop‑clock was
started and the volume of gas collected in the inverted measuring cylinder was measured every
10 seconds for 80 seconds.

4
(a) Use the inverted measuring cylinder diagrams to record the volume of gas collected in the
table.
inverted
total volume of
time / s measuring cylinder
gas collected / cm3
diagram
0
0
5
10
20
10
25
30
40
20
45
50
55
30
60
65
60
40
65
70
70
50
75
80
70
60
75
80
70
70
75
80
70
80
75
80
[2]
© UCLES 2019 0620/61/O/N/19

5
(b) Plot the results on the grid. Draw a smooth line graph.
80
70
60
50
total
volume
of gas 40
collected
/ cm3
30
20
10
0
0 10 20 30 40 50 60 70 80
time / s
[3]
(c) (i) One of the points is anomalous.
Circle this point on your graph. [1]
(ii)
From your graph, deduce the time taken to collect 40 cm3 of gas.
.............................. s [2]

6
(d) State one possible source of error in this experiment. Suggest one improvement to reduce this
source of error.
source of error ............................................................................................................................
improvement ...............................................................................................................................
[2]
(e) The average rate of the reaction can be calculated using the equation shown.
volume of gas collected / cm3

average rate of reaction =
time taken / s
(i) Calculate the volume of gas collected between 10 seconds and 30 seconds.
........................................................................................................................................ [1]
(ii)
Calculate the average rate of reaction between 10 seconds and 30 seconds. Include the
unit in your answer.
average rate of reaction = ..............................
unit = ..............................
[2]
(f) The student calculated that the total volume of gas collected in this reaction would be 85 cm3.
Suggest and explain why the actual volume of gas collected was different from 85 cm3.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
(g) S
ketch on the grid the graph you would expect if the experiment were repeated at a lower
temperature. Label this graph as L.[2]
[Total: 17]
© UCLES 2019 0620/61/O/N/19

7
3 Two substances, solid A and solid B, were analysed. Solid A was zinc nitrate.
Tests were done on the substances.
tests on solid A

Solid A was added to distilled water and the mixture shaken to dissolve solid A and produce
solution A. Solution A was divided into three equal portions in three test‑tubes.
(a) (i) A few drops of aqueous sodium hydroxide were added to the first portion of solution A.
observations................................................................................................................... [2]
(ii) An excess of aqueous sodium hydroxide was then added to this mixture.
observations .................................................................................................................. [1]
(b) (i) A few drops of aqueous ammonia were added to the second portion of solution A.
observations .................................................................................................................. [1]
(ii) An excess of aqueous ammonia was then added to this mixture.
observations .................................................................................................................. [1]
(c) Aluminium foil and aqueous sodium hydroxide were added to the third portion of solution A.
The mixture was heated and the gas produced was tested with litmus paper.
observations ...............................................................................................................................
............................................................................................................................................... [2]
tests on solid B

tests on solid B observations

test 1
A flame test was done on solid B. red flame
test 2
Solid B was dissolved in water.
Dilute nitric acid and aqueous silver nitrate were

yellow precipitate formed
added to the solution.
(d) Identify solid B.
............................................................................................................................................... [2]
[Total: 9]

8
4 Iodine dissolves in two different solvents: ethanol and hexane.
Plan an experiment to find out in which solvent iodine is the most soluble at room temperature.
You are provided with iodine, the two solvents and common laboratory apparatus.
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
...................................................................................................................................................... [6]
© UCLES 2019 0620/61/O/N/19

CHEMISTRY 0620/61
MARK SCHEME
Maximum Mark: 40
Published
Teachers.
components.

PUBLISHED
marking principles.
• marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond
the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
descriptors.

PUBLISHED
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range
may be limited according to the quality of the candidate responses seen).

PUBLISHED
1(a) beaker 1
1(b) steam / (water) vapour 1
condenses / cools 1
1(c) anhydrous copper(II) sulfate / cobalt(II) chloride (paper) 1
turns blue / pink 1
1(d) to suck gases / products through apparatus 1
1(e) turns milky 1
carbon dioxide formed 1
2(a) table of results 2

volume boxes completed
0, 27, 48, 62, 65, 74, 76, 77, 77
2(b) all points plotted correctly 2
best fit smooth line graph omitting anomalous point 1

at 40 s / 65 cm3
2(c)(i) point at 40 s / 65 cm3 1
2(c)(ii) value from graph 1
shown clearly 1

PUBLISHED
2(d) use of a 250 cm3 measuring cylinder / inaccurate measurements / readings 1
use a gas syringe / 100 cm3 measuring cylinder 1
2(e)(i) 35 cm3 1
2(e)(ii) 35 / 20 = 1.75 1
cm3 / s 1
2(f) volume of gas less / lower 1
gas / carbon dioxide dissolved in water 1
2(g) curve below original 1
approaching same level 1
3(a)(i) white 1
precipitate 1
3(a)(ii) clears / dissolves / colourless solution 1
3(b)(i) white precipitate 1
3(b)(ii) clears / dissolves / colourless solution 1
3(c) bubbles / effervescence 1
litmus turns blue 1

PUBLISHED
3(d) lithium 1
iodide 1
4 any 6 from: max 6

• known volume of ethanol
• add known mass of iodine
• stir / shake
• filter
• dry and weigh (undissolved) iodine
• repeat with hexane
• conclusion

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Syllabus

‘We think the Cambridge curriculum is superb preparation for university.’

1 Why choose this syllabus? ..................................................................................................... 2

2 Syllabus overview .................................................................................................................... 5

3 Subject content .......................................................................................................................10

4 Details of the assessment ................................................................................................... 28

6 What else you need to know .............................................................................................. 38

Changes to this syllabus

1 Why choose this syllabus?

Cambridge IGCSE Chemistry enables learners to:

Our approach encourages learners to be:

2 www.cambridgeinternational.org/igcse Back to contents page

Recognition and progression

Learn more at www.cambridgeinternational.org/recognition

Back to contents page www.cambridgeinternational.org/igcse 3

Teaching resources Exam preparation resources

4 www.cambridgeinternational.org/igcse Back to contents page

The aims are to:

Back to contents page www.cambridgeinternational.org/igcse 5

Support for Cambridge IGCSE Chemistry

6 www.cambridgeinternational.org/igcse Back to contents page

Core candidates take: Extended candidates take:

Paper 1 45 minutes Paper 2 45 minutes

and Core candidates take: and Extended candidates take:

Paper 3 1 hour 15 minutes Paper 4 1 hour 15 minutes

All candidates take

Paper 5 1 hour 15 minutes Paper 6 1 hour

Back to contents page www.cambridgeinternational.org/igcse 7

Candidates should be able to demonstrate knowledge and understanding of:

AO2 Handling information and problem solving

AO3 Experimental skills and investigations

Candidates should be able to:

8 www.cambridgeinternational.org/igcse Back to contents page

Weighting for assessment objectives

Assessment objectives as a percentage of the qualification

Assessment objective Weighting in IGCSE %

AO1 Knowledge with understanding 50

AO2 Handling information and problem solving 30

AO3 Experimental skills and investigations 20

Assessment objectives as a percentage of each component

Assessment objective Weighting in components %

Papers 1 and 2 Papers 3 and 4 Papers 5 and 6

AO1 Knowledge with understanding 63 63 0

AO2 Handling information and problem solving 37 37 0

AO3 Experimental skills and investigations 0 0 100

Back to contents page www.cambridgeinternational.org/igcse 9

1 The particulate nature of matter

10 www.cambridgeinternational.org/igcse Back to contents page

2.2.2 Methods of purification

3 Atoms, elements and compounds

Back to contents page www.cambridgeinternational.org/igcse 11

3.1 Atomic structure and the Periodic Table continued

3.2 Structure and bonding

3.2.2 Ions and ionic bonds

3.2.3 Molecules and covalent bonds

12 www.cambridgeinternational.org/igcse Back to contents page

3.2.5 Metallic bonding

Back to contents page www.cambridgeinternational.org/igcse 13

4.2 The mole concept

5 Electricity and chemistry