Cambridge IGCSE™

COMBINED SCIENCE 0653/21

Paper 2 Multiple Choice (Extended) October/November 2023
45 minutes

You must answer on the multiple choice answer sheet.

*7037727318*

You will need: Multiple choice answer sheet

Soft clean eraser
Soft pencil (type B or HB is recommended)

INSTRUCTIONS
 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 multiple choice answer sheet.
 Follow the instructions on the multiple choice answer sheet.
 Write in soft pencil.
 Write your name, centre number and candidate number on the multiple choice answer sheet in the
spaces provided unless this has been done for you.
 Do not use correction fluid.
 Do not write on any bar codes.
 You may use a calculator.

INFORMATION
 The total mark for this paper is 40.
 Each correct answer will score one mark.
 Any rough working should be done on this question paper.
 The Periodic Table is printed in the question paper.

This document has 16 pages. Any blank pages are indicated.

IB23 11_0653_21/3RP
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1 The diagram shows a plant absorbing carbon dioxide in order to carry out photosynthesis.

carbon dioxide

Which characteristic of all living organisms is this?

A movement
B nutrition
C excretion
D reproduction

2 Four different cells and functions are shown.

Which cell has the correct function stated?

A B

involved in reproduction moves mucus in the trachea

C D

involved in photosynthesis absorbs water from the soil

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3 What is diffusion?

A net movement of molecules down a concentration gradient

B net movement of molecules up a concentration gradient
C total movement of molecules down a concentration gradient
D total movement of molecules up a concentration gradient

4 Which graph shows the effect of increasing pH on enzyme activity?

A B

rate of rate of
reaction reaction

pH pH

C D

rate of rate of
reaction reaction

pH pH

5 What is the correct definition of a balanced diet?

A a diet in which all the components needed to maintain health are present in appropriate
proportions
B a diet which contains only carbohydrates, fats and proteins
C a diet which contains mostly protein and dietary fibre
D a diet which contains only vitamins and minerals

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6 The diagram shows what happens to fat in the alimentary canal.

enzyme (2)

large piece (1) (3) small (4)

of fat molecules

Which row correctly identifies 1, 2, 3 and 4?

1 2 3 4
A chemical lipase mechanical soluble
digestion digestion
B chemical protease ingestion insoluble
digestion
C mechanical lipase chemical soluble
digestion digestion
D mechanical protease ingestion insoluble
digestion

7 The diagram shows a section through the heart.

What causes valve X to close?

A contraction of the left ventricle

B contraction of the left atrium
C relaxation of the left ventricle
D relaxation of the left atrium

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8 Which chemical is used to test for carbon dioxide in expired air?

A Benedict’s solution
B distilled water
C iodine solution
D limewater

9 Six molecules of glucose are aerobically respired in an animal cell.

How many molecules of carbon dioxide are released in this process?

A 1 B 6 C 12 D 36

10 Which statement about auxin is correct?

A Auxin is always equally distributed.

B Auxin is made in the carpels only.
C Auxin spreads through the plant from the sepals.
D Auxin stimulates cell elongation.

11 Which row is correct for sexual reproduction?

genetically different one zygote

offspring produced parent produced

A   
B   
C   
D   

12 Which feature is a structural adaptation found in wind-pollinated flowers?

A Scent is produced.
B Nectar is produced.
C Petals are small or absent.
D Stigma is inside flower.

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13 The diagram shows part of the carbon cycle.

photosynthesis

green
Y
plants

animals

combustion
X

What are X and Y?

X Y

A fossil fuel carbon dioxide

B carbon dioxide oxygen
C fossil fuel oxygen
D oxygen carbon dioxide

14 Which substance is liquid at 25 C?

melting point boiling point

/ C / C

A –182 –161
B –100 80
C –77 –34
D 44 280

15 A solid is added to a liquid and stirred until the solid is no longer visible.

Which word describes the type of mixture that is formed?

A concentration
B solute
C solution
D solvent

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16 Which dot-and-cross diagram represents the outer shell electrons in a nitrogen molecule?

A B

N N N N

C D

N N N N

17 Iron(III) sulfate contains Fe3+ ions and SO42– ions.

What is the formula of iron(III) sulfate?

A FeSO4 B Fe3SO4 C Fe2(SO4)3 D Fe3(SO4)2

18 During electrolysis, positive ions are changed.

Which row describes what happens to the positive ions and identifies the electrode where this
happens?

what happens to
electrode
the positive ions

A gain electrons anode

B gain electrons cathode
C lose electrons anode
D lose electrons cathode

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19 Dilute hydrochloric acid and calcium carbonate react together to produce a gas.

The rate of reaction changes if the concentration of the hydrochloric acid or the temperature is
changed.

Which row about a change and how it affects the activation energy and the frequency of collisions
between reacting particles is correct?

change activation energy frequency of collisions

A increased concentration decreases increases

B increased concentration no effect no effect
C increased temperature decreases no effect
D increased temperature no effect increases

20 The equation for the redox reaction between aluminium and iron(III) oxide is shown.

2Al + Fe2O3  2Fe + Al 2O3

Which row identifies the substance that is reduced and the oxidising agent?

substance oxidising
reduced agent

A Al Fe2O3
B Al Al
C Fe2O3 Fe2O3
D Fe2O3 Al

21 Calcium oxide is added to water containing universal indicator. The universal indicator turns blue.

What is the pH of the solution?

A 1 B 6 C 7 D 11

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22 Acid X reacts with metal Y.

A colourless gas is given off and a pale green solution is produced.

Two tests are carried out on the solution.

test reagents added result

1 aqueous silver nitrate and dilute nitric acid white precipitate

2 aqueous sodium hydroxide green precipitate

What are acid X and metal Y?

acid X metal Y

A hydrochloric iron
B hydrochloric zinc
C sulfuric iron
D sulfuric zinc

23 Fluorine is at the top of Group VII in the Periodic Table.

It reacts with potassium iodide as shown.

fluorine + potassium iodide  iodine + substance Z

What is substance Z?

A fluoride
B potassium
C potassium fluoride
D potassium fluorine

24 Which statements about metals and their compounds are correct?

1 Copper reacts with dilute hydrochloric acid to give hydrogen.

2 Carbon does not react with aluminium oxide.
3 Hydrogen is formed when steam is passed over heated zinc.
4 Iron is more reactive than magnesium.

A 1 and 2 B 1 and 3 C 2 and 3 D 2 and 4

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25 Different reactions occur in the blast furnace.

Which substances are products in some reactions and reactants in other reactions in the blast
furnace?

A carbon dioxide and carbon monoxide

B carbon dioxide and carbon
C carbon monoxide and iron
D iron and carbon

26 Which gases can directly cause an enhanced greenhouse effect?

A carbon monoxide and carbon dioxide

B carbon dioxide and methane
C nitrogen dioxide and sulfur dioxide
D sulfur dioxide and methane

27 Which statement about alkanes is correct?

A Their molecules are unsaturated.

B They are generally reactive compounds.
C They are mixtures of carbon and hydrogen atoms only.
D They produce water when they burn.

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28 Which speed–time graph represents motion for which the acceleration is constant but not zero?

A B

speed speed

0 0
0 time 0 time

C D

speed speed

0 0
0 time 0 time

29 A glass block has a mass of 30 g and a volume of 15 cm3.

What is the density of the glass?

A 0.50 g / cm3 B 2.0 g / cm3 C 15 g / cm3 D 450 g / cm3

30 A spring that obeys Hooke’s law is stretched by a force of 4.0 N.

The length of the spring changes from 10 cm to 12 cm.

What is the spring constant of the spring?

A 0.33 N / cm B 0.50 N / cm C 2.0 N / cm D 3.0 N / cm

31 A car has a kinetic energy of 200 kJ as it passes a point P on a straight horizontal road.

A constant resultant force of 500 N then causes the car to accelerate.

What is the kinetic energy of the car when it has travelled a distance of 50 m past P?

A 2000 J B 25 000 J C 225 000 J D 5 000 000 J

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32 A man lifts a heavy load vertically, from the ground to above his head.

load

He then moves the load horizontally at constant speed.

During which motion is work done on the load, and why?

work is done reason

A when lifting the force exerted on the load is at right angles
to the direction of movement of the load
B when lifting the force exerted on the load is in the
same direction as the movement of the load
C when moving horizontally the force exerted on the load is at right angles
to the direction of movement of the load
D when moving horizontally the force exerted on the load is in the
same direction as the movement of the load

33 Which statement about a tidal energy power station is correct?

A It creates no environmental impact when being built.

B It does not work at night.
C It does not work when there is no wind.
D It supplies energy at predictable times.

34 The molecules in a substance are close together but free to change positions with each other.

Which substance at 20 C matches this description?

A air
B copper
C iron
D water

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35 A sound wave passes from one medium into a second medium.

What happens to the sound wave entering the second medium and why does this happen?

what happens why it happens

A it is reflected the frequency changes

B it is reflected the speed changes
C it is refracted the frequency changes
D it is refracted the speed changes

36 An earthquake wave shakes the ground at right angles to the direction of travel of the wave.

This wave has a frequency of 0.10 Hz and a wavelength of 30 000 m.

Which row shows the type of wave this is and its speed?

speed
type of wave
m/ s
A longitudinal 3 000
B longitudinal 300 000
C transverse 3 000
D transverse 300 000

37 The diagram shows two light rays from an object that pass through a thin converging lens. Each
point labelled F is a principal focus of the lens.

lens

object

F F

What is the nature of the image formed?

A right way up and larger than the object

B right way up and smaller than the object
C upside down and larger than the object
D upside down and smaller than the object

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38 The amplitude of a sound wave decreases and its frequency increases.

What happens to the sound heard?

A It becomes louder and its pitch becomes higher.

B It becomes louder and its pitch becomes lower.
C It becomes quieter and its pitch becomes higher.
D It becomes quieter and its pitch becomes lower.

39 There is a current of 6.0 A in a wire.

How much charge flows through the wire in 2.0 minutes?

A 0.050 C B 3.0 C C 12 C D 720 C

40 A circuit contains three ammeters, P, Q and R, and three identical lamps.

P
A

Q
A

R
A

How do the readings on the ammeters compare?

A All three ammeters show the same reading.

B The reading on P is greater than the reading on Q and greater than the reading on R.
C The reading on P is less than the reading on Q and less than the reading on R.
D The three ammeters show three different readings.

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BLANK PAGE

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publisher will be pleased to make amends at the earliest possible opportunity.

To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
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 Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge
Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.

© UCLES 2023 0653/21/O/N/23

 The Periodic Table of Elements
Group

© UCLES 2023
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
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
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

0653/21/O/N/23
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 89–103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118
actinoids
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson
– – – – – – – – – – – – – – – – –

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.).