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Pearson Edexcel International GCSE (9–1)

Tuesday 11 June 2024
Morning (Time: 1 hour 15 minutes) Paper
reference 4CH1/2CR
Chemistry  

UNIT: 4CH1
PAPER: 2CR

You must have: Total Marks

Calculator, ruler

Instructions
• Use black ink or ball-point pen.
• Fill in the boxes at the top of this page with your name,
centre number and candidate number.
• Answer all questions.
• Answer the questions in the spaces provided
– there may be more space than you need.
• Show all the steps in any calculations and state the units.
Information
• The total mark for this paper is 70.
• The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.

Advice
• Read each question carefully before you start to answer it.
• Try toyour
Write answers neatly and in good English.
• Checkanswer every question.
• your answers if you have time at the end.
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P73426A
©2024 Pearson Education Ltd.
F:1/1/1/1/1/1/
*P73426A0124*
 2
The Periodic Table of the Elements
1 2 3 4 5 6 7 0
1 4
H He
hydrogen helium

Key 1 2

7 9 relative atomic mass 11 12 14 16 19 20

Li Be atomic symbol B C N O F Ne
lithium beryllium name boron carbon nitrogen oxygen fluorine neon
3 4 atomic (proton) number 5 6 7 8 9 10

23 24 27 28 31 32 35.5 40
Na Mg Al Si P S Cl Ar
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 63.5 65 70 73 75 79 80 84
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
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

85 88 89 91 93 96 [98] 101 103 106 108 112 115 119 122 128 127 131
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
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 [209] [210] [222]
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

*P73426A0224*
55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86

[223] [226] [227] [261] [262] [266] [264] [277] [268] [271] [272]
Fr Ra Ac* Rf Db Sg Bh Hs Mt Ds Rg Elements with atomic numbers 112–116 have been reported but not fully
francium radium actinium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium
authenticated
87 88 89 104 105 106 107 108 109 110 111

* The lanthanoids (atomic numbers 58–71) and the actinoids (atomic numbers 90–103) have been omitted.

The relative atomic masses of copper and chlorine have not been rounded to the nearest whole number.

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 Answer ALL questions.
Some questions must be answered with a cross in a box . If you change your mind about an

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answer, put a line through the box and then mark your new answer with a cross .
1 This question is about sulfur.
(a) The diagram represents the electronic configuration of an atom of sulfur.

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(i) Which period of the Periodic Table contains sulfur?
(1)
A 2

B 3

C 4

D 6

(ii) What is the charge on a sulfide ion?

(1)
A 1+
B 2+
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C 1–
D 2–

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*P73426A0424* 
 (b) When a mixture of sulfur and zinc is heated to a high temperature a reaction
occurs, forming the compound zinc sulfide, ZnS
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(i) Give a reason why the mixture of sulfur and zinc needs heating before a
reaction occurs.
(1)

Energy need to be greater than of atoms

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

activation energy here energy is supplied

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

(ii) Calculate the relative formula mass (Mr) of zinc sulfide.

[for Zn, Ar = 65 for S, Ar = 32]
(1)

687 32 97

97
Mr = .................. ... ... ... ... .. ... ... ... ... ... ... .. ... ... ... .
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(Total for Question 1 = 4 marks)

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 *P73426A0524* Turn over
2 (a) The diagram represents an atom of an element.

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+ +
+
W +

(i) What is the name of the particle labelled W?

(1)

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A electron
B ion

C neutron

D proton

(ii) What is the mass number of this atom?

(1)
A 4
B 5

C 9

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*P73426A0624* 
 (b) These are the symbols for the two isotopes of lithium.
6 7
Li Li
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3 3

(i) In terms of sub-atomic particles, give one similarity and one difference
between the two isotopes.
(2)
similarity

same number of protons

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

difference

Different number of neutrons

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

(ii) A sample of lithium contains 7.5% of 63Li and 92.5% of 73Li

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Calculate the relative atomic mass (Ar) of this sample of lithium.

(2)

5 6 92.5 7

100
6.925
6 925
Ar = .................. ... ... ... ... .. ... ... ... ... ... ... .. ... ... ... .
(Total for Question 2 = 6 marks)
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 *P73426A0724* Turn over
3 This question is about magnesium metal and its compounds.
(a) (i) The diagram represents the structure of magnesium.

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Complete the diagram by adding the labels.
(2)

Protons
...................................... ... ... ... .. ... ... ... ... .

Delocalised eleitron
...................................... ... ... ... .. ... ... ... ... .

(ii) Explain why magnesium is malleable.

(2)

Has layers of ions which can slide

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

each other

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over
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

(b) Magnesium burns in oxygen gas to form solid magnesium oxide.

(i) Complete the chemical equation for the reaction by balancing the equation
and adding the state symbols.
(2)

2 Mg(s) + O2(................ ) → 2 s)
MgO(................
g
................ ................

(ii) Give a reason why magnesium is oxidised in this reaction.

(1)

Magnesium
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gains oxygen
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

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*P73426A0824* 
 (c) A student uses this method to make a solution of magnesium chloride.
Step 1 measure 25 cm3 of dilute hydrochloric acid into a beaker
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Step 2 add magnesium powder a little at a time

Step 3 keep adding magnesium powder until it is in excess
Step 4 remove the excess magnesium powder by filtration

This is the equation for the reaction.

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)

(i) Give a reason why the student uses magnesium powder rather than
magnesium ribbon.
(1)

Faster rate of reaction reaction finishes

quicker
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..
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. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

(ii) Give a reason why the student adds an excess of magnesium in step 3.
(1)

sure that all the acid has rental

Makes
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

and that it only forms magnesium chloride

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

(iii) Calculate the minimum mass of magnesium needed to react with

25.0 cm3 of 2.00 mol / dm3 hydrochloric acid.
[for Mg, Ar = 24]
(3)

25 1000 0 025

E h Hr
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2 07025
0.05 11
1.2 1.2
Nk 0.08 mass = ......................... ... ... .. ... ... ... ... ... .. ... ... ... ... g
(Total for Question 3 = 12 marks)

9
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4 This question is about the manufacture of ethanol by the fermentation of glucose.
(a) Fermentation needs to be done in the absence of air.

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Give two other conditions needed for fermentation.
(2)

30 40 C
1 . .. . . . ...................... .. ... .. .. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . ........................................................................................................................ ... ... ... ... .. ... ... ... ... . ... ... ... ... ... ..

Zymase
2 . .. . . . ......................
enzyme in yeast
.. ... .. .. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . ........................................................................................................................ ... ... ... ... .. ... ... ... ... . ... ... ... ... ... ..

(b) Explain why fermentation needs to be done in the absence of air.

(2)

If air is present yeast would produce carbon

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

dioxide and water instead of ethanol Ethanol can

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

also oxidise into ethamoic avid

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

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(c) (i) Complete the equation for fermentation.
(1)

CO2
C6H12O6 → 2C2H5OH + 2..............................................................

(ii) A mixture containing 500 mol of glucose is fermented.

A mass of 5750 g of ethanol is obtained.
Calculate the percentage yield.
[for ethanol, Mr = 46]
(3)

500
M 23000
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13 0 100 25
percentage yield = .......................... ... ... ... ... ... .. ... ... ... ... ... .. .. %25
(Total for Question 4 = 8 marks)

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*P73426A01024* 
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*P73426A01124*
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11
5 Sodium sulfate can be prepared by the reaction between sodium hydroxide solution
and sodium hydrogensulfate (NaHSO4) solution.

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This is the equation for the reaction.

NaOH(aq) + NaHSO4(aq) → Na2SO4(aq) + H2O(l)

Sodium hydrogensulfate solution is acidic.

A student adds 25.0 cm3 of sodium hydroxide solution to a conical flask and adds
two drops of indicator.
The student does a titration.
(a) (i) Name a piece of apparatus that should be used to add
25.0 cm3 of sodium hydroxide solution to the conical flask.
(1)

Pipette
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

(ii) Describe the method the student should use to find the accurate
volume of sodium hydrogensulfate solution needed to neutralise the

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25.0 cm3 of sodium hydroxide solution.
(5)

Fill a burette with sodium hydrogensulfate below

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

to prevent spills
eye level
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

Slowly add the sodium hydrogen sulfate to

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the conical flush using the burette while giving

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the conical flask a regular swirl

Add it
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

dropwise when the acid is nearly neutralised

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

Indicator changes colour once the solution me bean

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

neutralised
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. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

Record the volume of sodium hydrogen sulfate solution

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

used and repeat experiment for more reliable

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

results
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

12
*P73426A01224* 
 (b) The student repeats the titration without the indicator and forms a solution of
sodium sulfate.
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Describe how the student can obtain pure, dry crystals of hydrated sodium sulfate
from the solution.
(4)

Gently heat the solution to evaporate some of the

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

water until crystals form on glass rod

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

Leave the solution

to cool and to crystallion
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

Filter the crystals using filter paper am

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

funnel
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

Dry the crystals by leaving it in an

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

Oven
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 (c) Crystals of hydrated sodium sulfate decompose when heated.
This is the equation for the decomposition.

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Na2SO4.xH2O → Na2SO4 + xH2O

A student uses this apparatus to find the value of x.

hydrated sodium sulfate

heat

ice water

The student heats the crystals until the decomposition is complete.

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The table shows the student’s results.

mass of empty test tube in g 25.12

mass of test tube and Na2SO4.xH2O in g 31.56

mass of test tube and Na2SO4 in g 27.96

Use the results to calculate the value of x.

[for Na2SO4 , Mr = 142 for H2O, Mr = 18]
(4)

31,56 27.96 3.6

27.96 28.12 2.84
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78 0.22 10.02
8 1
822 10
to
value of x = ................... ... .. .. ... .. ... ... ... ... ... .. ... ... ... ... ..
(Total for Question 5 = 14 marks)

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15
6 This question is about electrolysis.
(a) This apparatus is used to collect the gases produced when an electric current

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passes through dilute sulfuric acid.

dilute sulfuric acid

oxygen

hydrogen

inert electrode inert electrode

+ –

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power
supply

(i) Name a suitable material for the inert electrodes.

(1)

Graphite
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

(ii) Give a test to show that the gas produced at the positive electrode is oxygen.
(1)

Relights a glowing splint

. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

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(iii) Give a test to show that the gas produced at the negative electrode
is hydrogen.
(1)
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Squeaky pop using lit splint

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*P73426A01624* 
 (iv) Give an ionic half-equation for the formation of hydrogen at the
negative electrode.
(1)
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24 2 Hz
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(v) The oxygen gas in the tube has a volume of 17.8 cm at rtp. 3

Calculate the mass, in grams, of oxygen gas in the tube.

Give your answer to 3 significant figures.
[for O2 at rtp, molar volume = 24 000 cm3]
(3)

NV 24000 n th
4 24000 1
000
0 M 0.01 9
17.8
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51 24000

n
0.0114
mass of oxygen = ......................... ... ... .. ... ... ... ... ... .. ... ... ... ... g
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 *P73426A01724* Turn over
 (b) This apparatus is used to electrolyse a concentrated solution of sodium chloride.

chlorine

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hydrogen

concentrated solution
of sodium chloride

– power +
supply

(i) Give a reason why sodium chloride solution conducts electricity.

(1)

Ioni compound molten contains ions that can

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move and carry charge

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(ii) The positive ions in the solution are H+ and Na+.

Give a reason why hydrogen forms at the negative electrode rather
than sodium.
(1)
Sodium is more reactive than hydrogen
. . . .. . . . . . ........................ .. .. .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . ............................................................................................................................ .. ... .. ... .. ... ... . . .. ... ... ... ... ... .. ..

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(iii) A sample of the solution is taken from near the negative electrode.
The sample is tested with universal indicator.
Explain the final colour of the universal indicator.
(2)
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Blue sodium hydroxide solution is alkation

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(Total for Question 6 = 11 marks)

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*P73426A01824* 
 7 Gaseous ethanol is manufactured by reacting ethene gas with steam.
This is the equation for the reaction.
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C2H4(g) + H2O(g)  C2H5OH(g)

(a) (i) The pressure on an equilibrium mixture of the three gases is decreased. All the
other conditions are kept the same.
Predict the effect of this change on the yield of ethanol at equilibrium, giving
a reason for your answer.
(2)

Yield of ethanol decreases

as decrease in
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pressure favors the reation that produces the most

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amount of molecules
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(ii) Predict the effect of adding a catalyst on the yield of ethanol at equilibrium,
giving a reason for your answer.
(2)

No change to equilibrium catalyst both

speeds up
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forward
the and backward nation
by the same
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rate
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 (b) The equation shows the displayed formulae for the reactants and products.
H H

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H H O
C C +  H C C O H
H H H H
H H

The table gives the bond energies.

Bond Bond energy in kJ / mol

C H 414

C C 614

O H 463

C C 346

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C O 358

(i) Using the data in the table and the equation, show that the enthalpy change,
ΔH , is approximately –40 kJ / mol.
(3)

4 414 61471463 2
3196
5 414 346 3887463
3237
3196 3237 41
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40
(ii) Explain, in terms of bonds broken and bonds made, why this reaction
is exothermic.
(2)

Energy released by boards formed is greater

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than energy used to break bonds here heat

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is released so exothermic reauthon

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*P73426A02024* 
 (iii) Draw an energy level diagram for the reaction between ethene and steam.
Label the enthalpy change, ΔH .
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(3)

energy

Energy Friction
L
ethanol

1H

there steam

Progress of reaction
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(c) Ethanoic acid reacts with ethanol to form ester A and water.
(i) Complete the equation by adding the displayed formula of ester A.
(2)

H O
O
H C C
H H
H O H

+  +

H H

H C C O H
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H H

ester A

(ii) Give the name of ester A.

(1)

. . .. . . . . .. . ...................... .. .. ... .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . . .. ........................................................................................................................ ... ... ... ... .. ... ... .. .. ... ... ... ... ... .. ...

(Total for Question 7 = 15 marks)

TOTAL FOR PAPER = 70 MARKS

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