Name: _______________________________________________

Assessment
Unit 1

Time: 1 hour

Total marks available:

Total marks achieved: ______

Questions
Q1.

A sample of hydrated calcium sulfate, CaSO4.xH2O , was heated to constant mass. 3.405 g of anhydrous
calcium sulfate and 0.900 g of water were formed.

What is the value of x?

[Relative formula mass: CaSO4 = 136.2]

(1)
A 0.5
B 2
C 3
D 4

(Total for question = 1 mark)

Q2.

Answer the question with a cross in the box you think is correct . If you change your mind about
an answer, put a line through the box and then mark your new answer with a cross .

In 1.31 g of a chloride of titanium, there is 0.528 g of titanium.

What is the empirical formula of this titanium chloride?

[ Ar values: Ti = 47.9 Cl = 35.5 ]

A TiCl
B TiCl2
C TiCl3
D Ti2Cl4

(Total for question = 1 mark)

Q3.

What is the relative formula mass of hydrated ammonium iron(II) sulfate, (NH4)2Fe(SO4)2.6H2O?

[Relative atomic masses (Ar ): H = 1.0 N = 14.0 O = 16.0 S = 32.1 Fe = 55.8]

(1)
A 284
B 302
C 312
D 392
(Total for question = 1 mark)
Q4.

A sample of neon contains the following isotopes.

What is the relative atomic mass of neon to two decimal places?

(1)
A 20.00
B 20.09
C 20.18
D 21.00

(Total for question = 1 mark)

Q5.

Answer the question with a cross in the box you think is correct . If you change your mind about
an answer, put a line through the box and then mark your new answer with a cross .

What is the percentage atom economy, by mass, for the production of hydrogen in the reaction shown?

[Ar values: H = 1.00 C = 12.0 O = 16.0]

A 8.8%
B 17.6%
C 21.4%
D 82.4%

(Total for question = 1 mark)

Q6.

Which pair of substances contains the same number of moles at room temperature and pressure (r.t.p.)?

[Ar values Ca = 40, Li = 7, Al = 27, Mg = 24. Molar volume of gas at r.t.p. = 24 dm3 mol−1]
(1)
A 24 dm3 of chlorine, Cl2, and 20 g of calcium, Ca
B 24 dm3 of oxygen, O2, and 14 g of lithium, Li
C 1.2 dm3 of hydrogen, H2, and 2.7 g of aluminium, Al
D 1.2 dm3 of nitrogen, N2, and 1.2 g of magnesium, Mg

(Total for question = 1 mark)

Q7.

Answer the question with a cross in the box you think is correct . If you change your mind about
an answer, put a line through the box and then mark your new answer with a cross .

How many molecules are there in 44.0 g of carbon monoxide?

A 3.83 × 1023
B 6.02 × 1023
C 9.46 × 1023
D 1.89 × 1024

(Total for question = 1 mark)

Q8.

Answer the question with a cross in the box you think is correct . If you change your mind about
an answer, put a line through the box and then mark your new answer with a cross .

A compound has Mr = 84 and its composition by mass is 71.4% carbon, 9.6% hydrogen and 19.0%
oxygen.

What is the molecular formula of this compound?

[ Ar values: H = 1.0 C = 12.0 O = 16.0 ]

A C4H3O2
B C4H4O2
C C5H8O
D C6H10O

(Total for question = 1 mark)

Q9.

Propene, C3H6, is produced in the dehydration of propanol.

C3H7OH → C3H6 + H2O

What is the mass, in g, of propene formed from 3.42 g of propanol when the yield is 85.2 % ?

[Relative molecular masses (Mr): C3H7OH = 60 C3H6 = 42]

(1)
A 2.04
B 2.39
C 2.91
D 4.16

(Total for question = 1 mark)

Q10.

A 2 kg sample of water contains 40 parts per million (ppm) by mass of nitrate ions.

What is the mass, in g, of nitrate ions in this sample?

(1)
A 8 × 10−2
B 5 × 10−5
C 8 × 10−5
D 5 × 10−8

(Total for question = 1 mark)

Q11.

This question is about the structure of atoms.

(a) State what is meant by the term orbital.

(2)
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(b) State the shape of an s orbital and the shape of a p orbital.

(1)

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(c) Describe what can be deduced about the electronic structure of sodium from its successive ionisation
energies.
(3)
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(d) (i) The log of the fourth ionisation energy for six elements is shown in the table.
 Plot a graph of these data.
(3)

(ii) Use your graph to estimate the fourth ionisation energy for sodium, in kJ mol–1.
(1)

(iii) Suggest why the fourth ionisation energies of neon and sodium are similar in magnitude even
though the elements are in different periods of the Periodic Table.
(1)
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(Total for question = 11 marks)

Q12.

Magnesium is a metal in Group 2 of the Periodic Table. It reacts with chlorine to form the salt magnesium
chloride, MgCl2.

(a) Draw a dot-and-cross diagram for magnesium chloride.

Show outer shell electrons only.
(1)

(b) Magnesium conducts electricity when it is in the solid state. Magnesium chloride conducts electricity
when it is molten or dissolved in water but not when it is in the solid state.
Explain these observations.
(3)
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(c) Magnesium chloride can also be made by reacting magnesium oxide with dilute hydrochloric acid.

MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O(l)

(i) Write the ionic equation, including state symbols, for this reaction.
(1)

(ii) Calculate the minimum volume of 2.00 mol dm−3 hydrochloric acid needed to completely react with
2.45 g of magnesium oxide.
(3)
 Minimum volume of hydrochloric acid = ........................................................... cm3

(d) A further method for making magnesium chloride is by reacting magnesium carbonate with dilute
hydrochloric acid.

MgCO3(s) + 2HCl(aq) → MgCl2(aq) + H2O(l) + CO2(g)

Calculate the maximum mass of magnesium chloride that could be formed when 2.25 g of magnesium
carbonate is added to excess dilute hydrochloric acid.
(2)

Maximum mass magnesium chloride = ........................................................... g

(e) Explain why the reaction to make magnesium chloride from magnesium oxide has a higher atom
economy than the reaction using magnesium carbonate.
No calculation is required.
(2)
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(Total for question = 12 marks)

Q13.

This question is about phosphorus and some of its compounds.

(a) The atomic number of phosphorus is 15.

(i) Complete the electronic configuration of a phosphorus atom using the electrons-in-boxes notation.
(1)

(ii) Explain why the first ionisation energy of phosphorus is greater than that of sulfur.
(2)
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(b) Phosphorus has a melting temperature of 44 °C.

Silicon has a melting temperature of 1410 °C.
Explain why the melting temperature of phosphorus is much lower than that of silicon.
(3)
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(c) Phosphorus(V) chloride, PCl5 , exists as covalent molecules in the gaseous state.
(i) Complete the table for a PCl5 molecule.
(3)
 (ii) In the solid state, phosphorus(V) chloride is ionic.
The cation and anion each have one phosphorus atom but a different number of chlorine atoms.
The cation is tetrahedral and the anion is octahedral.
Predict the formula of each ion. Include the charge on each ion.
(2)
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(d) In an experiment, 8.00 cm3 of 0.250 mol dm−3 sodium hydroxide, NaOH, reacted completely with 10.0
cm3 of 0.100 mol dm−3 phosphoric acid, H3PO4 .
Use these data to deduce the balanced equation for this reaction.
You must show your working.
(3)

(e) Hydrated magnesium phosphate has the formula Mg3(PO4)2.yH2O .

A sample of this compound contains 78.5% by mass of anhydrous magnesium phosphate.
Deduce the value of y.
You must show your working.
[Molar mass of anhydrous magnesium phosphate, Mg3(PO4)2 = 262.9 g mol−1]
(2)

(Total for question = 16 marks)

Q14.

This question is mainly about alkenes.

(a) A few drops of bromine water are added to separate test tubes of propane and propene and the
mixtures are shaken.
Describe what is seen at the end of each experiment.
(2)
Propane

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Propene

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(b) Give the reagents and conditions for each of these conversions.
(i) CH2==CH2 → CH3CH2OH
(1)
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(ii) CH2==CH2 → CH2OHCH2OH
(1)
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(c) Draw the structure of Z-3-methylpent-2-ene.

(1)

(d) Exactly 720 cm3 of hydrogen gas, measured at room temperature and pressure (r.t.p.), reacted with
0.010 mol of an alkene to form an alkane.
Deduce the number of double bonds in one molecule of the alkene.
You must show your working.
[Molar volume of gas at r.t.p. = 24 000 cm3 mol−1]
(2)
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(e) A student drew a mechanism for the addition of bromine to ethene.

Describe the three changes needed to correct this student's mechanism.

(3)
Change 1

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Change 2

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Change 3

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(f) Part of the structure of a polymer is shown.

Draw the structure of the monomer used to make this polymer.

(1)

(Total for question = 11 marks)

Q15.

This question is about compounds containing chlorine.

(a) A precipitate of silver chloride is formed when silver nitrate solution reacts with sodium chloride
solution.
A student wrote an ionic equation for the reaction.
Ag2+(l) + 2Cl–(l) → AgCl2(s)
Explain why this equation is incorrect, even though it is balanced.
(2)
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(b) A sample of a compound is analysed and found to contain only 3.09 g carbon, 0.26 g hydrogen and
9.15 g chlorine.
The molar mass of the compound is 97.0 g mol–1.
Calculate the molecular formula of this compound.
You must show your working.
(3)
(c) Nitrogen trichloride has the formula NCl3.
(i) A sample of nitrogen trichloride contained only nitrogen atoms with mass number 14, and chlorine
atoms with mass numbers 35 and 37.
Give the formula and mass/charge ratio for each of the four ions responsible for the molecular ion
peaks in the mass spectrum of nitrogen trichloride.
(2)

(ii) Complete the table to predict the shape and Cl—N—Cl bond angle in nitrogen trichloride.
(3)

(d) Aluminium chloride exists as an ionic lattice in the solid state and as a covalent dimer, Al2Cl6, in the
gas phase, just above its boiling temperature.
(i) Explain why aluminium chloride in the solid state has significant covalent character.
(2)
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(ii) Describe how two AlCl3 molecules are joined together in the dimer.
Include a diagram in your answer.
(2)

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(Total for question = 14 marks)