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Mark Scheme (Results)

January 2022

Pearson Edexcel International GCSE

In Chemistry (4CH1) Paper 1C and Science

(Double Award) (4SD0) Paper 1C
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Edexcel and BTEC Qualifications

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January 2022
Question Paper Log Number P70701A
Publications Code 4CH1_1C_2201_MS
All the material in this publication is copyright
© Pearson Education Ltd 2022
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General Marking Guidance

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 All candidates must receive the same treatment. Examiners
must mark the first candidate in exactly the same way as they
mark the last.
 Mark schemes should be applied positively. Candidates must
be rewarded for what they have shown they can do rather than
penalised for omissions.
 Examiners should mark according to the mark scheme not
according to their perception of where the grade boundaries
may lie.
 There is no ceiling on achievement. All marks on the mark
scheme should be used appropriately.
 All the marks on the mark scheme are designed to be awarded.
Examiners should always award full marks if deserved, i.e. if
the answer matches the mark scheme. Examiners should also
be prepared to award zero marks if the candidate’s response
is not worthy of credit according to the mark scheme.
 Where some judgement is required, mark schemes will
provide the principles by which marks will be awarded and
exemplification may be limited.
 When examiners are in doubt regarding the application of the
mark scheme to a candidate’s response, the team leader must
be consulted.
 Crossed out work should be marked UNLESS the candidate has
replaced it with an alternative response.
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Question

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Answer Notes Marks

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number

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1 (a) (i) chromatography 1

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(ii) fractional distillation 1

(iii) simple distillation 1

(b) M1 two / different elements ALLOW (two) different 2

atoms

M2 (chemically) joined / bonded together ALLOW a description of

bonding

(c) (i) 4 1

1
(ii) 20
Total for question = 7 marks
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Question

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Answer Notes Marks

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number

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2 (a) (i) M1 oxygen / air 2

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M2 water

(ii) (hydrated) iron(III) oxide REJECT (hydrated) iron 1

(II) oxide

(iii) C 1
C is the correct answer because rusting involves the
oxidation of iron.
A is not the correct answer because the rusting of
iron is not combustion.
B is not the correct answer because the rusting of
iron is not neutralisation.
D is not the correct answer because the rusting of
iron is not thermal decomposition.

(b) (i) galvanising ALLOW galvanisation 1

IGNORE sacrificial
protection

(ii) M1 zinc is more reactive (than iron) ALLOW zinc is higher in 2

the reactivity series
(than iron)

M2 zinc reacts / oxidises / corrodes REJECT references to

before / instead of iron zinc rusting

(iii) Any two from: 2

painting ALLOW powder coating

plastic coating

oiling / greasing

chromium plating

sacrificial protection

cathodic protection

Total for question = 9 marks

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Question

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Answer Notes Marks

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number

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3 (a) solid to liquid melting 3

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solid to gas sublimation

liquid to solid freezing

(b) (i) diffusion ALLOW diffusing 1

(ii) Any one from: 1

ammonia travels further (in the same time)

the ammonium chloride / (white) ring / solid forms

further away from the ammonia

the ammonium chloride / (white) ring / solid forms

closer to the hydrochloric acid

(iii) Any one from: 1

gas particles move in random directions

gas particles collide with air particles / each other

gas particles collide with the wall of the tube

Any one from:

1
(iv) eye protection / wear safety glasses / goggles

wear gloves

apron / lab coat

ALLOW put a bung /

cork in both ends
Total for question = 7 marks
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Question

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Answer Notes Marks

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number

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4 (a) (i) Any one from: 1

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to increase the rate of reaction

to give the particles enough energy to react ALLOW because copper

does not react with
oxygen when copper is
cold
ALLOW so that copper
will react with oxygen

(ii) because Ar does not (readily) gain / lose / share ACCEPT argon has a full 1
electrons outer shell / valence
shell of electrons

(iii) copper(II) oxide ALLOW copper oxide 1

REJECT copper(I) oxide

(b) (i) results are the same (at the end) ALLOW results stop 1
decreasing

(ii) M1 volume oxygen = 20 cm 3 3

M2 total volume = 253 cm3

M3 (20÷253)×100 = 7.9% ALLOW correct

evaluation from M1 and
M2
ALLOW any number of
significant figures
REJECT incorrect
rounding

Correct answer of 7.9%

with or without working
scores 3

(iii) Any one from: 1

there is a leak in the apparatus

temperature was not the same for all readings

the apparatus was not left to cool (to room

temperature)

IGNORE not all oxygen

reacted
Total for question = 8 marks
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Question

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5 (a) (i) relative mass proton 1 All 4 correct scores 2 2

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2 or 3 correct scores 1

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relative mass neutron 1

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relative charge proton +1

relative charge neutron 0

(b) (i) M1 atoms (of the same element) with the same ALLOW atoms with the 2
number of protons same atomic number
ALLOW atoms with the
same number of
electrons

M2 but different numbers of neutrons ALLOW but different

mass numbers

(ii) M1 number of protons and electrons = 12 2

M2 number of neutrons = 14

(iii) 2

scores 2 marks

M1 multiplies each mass number by the percentages

M2 adds multiples together and divides by 100

(24 x 0.79) + (25 x 0.10)

+ (26 x 0.11) scores
both marks

(iv) M1 24.32÷(6.022×1023) 2

M2 4.039 × 10-23 ALLOW ecf from M1 as

long as answer is given
to 4 sig figs

Correct answer of 4.039

× 10-23 g to 4 sig sigs
scores 2 with or without
working

(c) (moles of MgO) = 0.40 1

Total for question = 11

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Question

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Answer Notes Marks
number

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6 (a) Any three from: 3

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M1 sodium (atom) loses electron(s)

p/
M2 oxygen (atom) gains electron(s)

M3 sodium loses 1 electron AND oxygen gains 2

electrons

OR

M3 (both atoms become ions with configuration) 2.8

any mention of sharing

of electrons scores 0

(b) 62 1

(c) Any two from: 2

M1 (sodium oxide has) ions / (giant) ionic structure

M2 ions / electrons cannot flow / move

M3 no delocalised electrons

(d) M1 flame test ALLOW any description 2

of a flame test

M2 yellow colour ALLOW orange or

yellow-orange
M2 dep on M1 or
mention of flame
(e) 2Na2O → 2Na + Na2O2 1

Total for question = 9 marks

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Question

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Answer Notes Marks

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number

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7 (a) C 1

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C is the correct answer because a precipitate of
calcium sulfate will form in tube 1, no precipitate
will form in tube 2 as both products are soluble in
water and a precipitate of copper(II) carbonate will
form in tube 3.
A, B and D are not the correct answers as no
precipitate will form in tube 2.

(b) (i) white 1

(b) (ii) Any five from: 5

M1 filter

M2 heat/boil (the solution)

M3 to evaporate some of the water ALLOW until crystals

form on the end of a
glass rod
ALLOW until crystals
first start to form
ALLOW until the
solution is saturated

M4 leave / cool (to crystallise) M4 dep on M2

M5 pour off excess liquid OR filter (to obtain M5 dep on crystals

crystals) having been formed

IGNORE references to
washing

M6 suitable method of drying the e.g. place in (warm)

crystals oven / leave to
dry (in warm place) /
use filter
paper / kitchen towel /
/ desiccator

If solution heated to
dryness or
left to evaporate all of
the water
only M1 and M2 can be
awarded.

If method produces
silver chloride only M1
and M6 can be awarded

(iii) any one from: 1

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to make sure the silver nitrate and sodium chloride ALLOW so all the

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fully reacted reactants react OR so

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OR so neither reagent is
in excess

to make sure the products only contained silver

chloride and sodium nitrate

to ensure the highest possible yield

ALLOW to make sure

the sodium nitrate
(crystals) would be pure
ALLOW If either solution
were in excess, it would
contaminate the sodium
nitrate OWTTE
Total for question = 8 marks
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Question

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Answer Notes Marks

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number

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8 (a) (i) A 1

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(ii) C 1

(iii) propene 1

(iv) M1 same molecular formula 2

M2 different structural / displayed formulae

(b) (i) CH3Br + HBr ALLOW balanced 1
equations for multiple
substitutions

(ii) substitution 1

(c) (i) M1 37.8÷12, 6.3÷1, 55.9÷35.5 3

M2 3.15, 6.3, 1.57 M2 subsumes M1

M3 divide by smallest to get 2:4:1

OR

M1 Mr of C2H4Cl = 63.5

M2 24/63.5 x 100 and 4/63.5 x 100 and 35.5/63.5

x100

M3 37.8% and 6.3% and 55.9% M3 must be calculated

(ii) M1 127÷63.5=2
2
M2 Molecular formula = C4H8Cl2

Answer of C4H8Cl2
without working scores
2
(d) (i) 2

M1 two carbon atoms both with 2 H atoms

M2 two carbon atoms both with 1 H atom and 1 CH3

group and nothing attached to the joining bonds
Marks are independent

(ii) Any one from: 1

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toxic / greenhouse gases are produced when burned

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Total for question = 15 marks

Question
Answer Notes Marks
number
9 (a) M1 to prevent acid splashing out OR IGNORE solid leaving 2
so only (carbon dioxide) gas leaves the flask the flask
REJECT prevents gas
escaping

M2 so the decrease in mass is close to the actual

value OR so that the decrease in mass is only due to
the gas

(b) M1 CaCO3(s) + 2HCl(aq) 2

M2 H2O(l) + CO2(g)

(c) (i) the hydrochloric acid has all reacted 1

1
(ii) mass stays the same / stops decreasing ALLOW effervescence /
fizzing stops
ALLOW the curve levels
off

(iii) M1 0.98
2
M2 (0.98÷44) = 0.022 ALLOW any number of
significant figures
REJECT incorrect
rounding
ALLOW M1÷44

Correct answer of 0.022

moles with or without
working scores 2 marks

(iv) M1 tangent shown on graph

3
M2 method of calculating gradient
(change in y ÷ change in x)

M3 rate of reaction in g/s ALLOW ECF from M2

Answer of 0.005 – 0.006

with a tangent shown
on the graph scores 3
with or without other
working.
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Answer of 0.015g/s (the

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(d) (i) M1 the rate of reaction increases as the percentage 2
concentration increases

M2 the rate of reaction is (directly) proportional to M2 subsumes M1

the percentage concentration

(ii) M1 change in number of particles (per unit volume) ALLOW particles are 2
closer together or
further apart

M2 change in collisions per unit time ALLOW change in

frequency of collisions
REJECT increased /
changed energy / speed
Total for question = 15 marks
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Question

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Answer Notes Marks

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number

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10 (a) (i) 2

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ALLOW dots, crosses or
any combination.

M1 6 bonding electrons

M2 2 non-bonding electrons on each atom M2 dep on M1

(ii) M1 shared pair(s) of electrons

2
M2 attracted to (two) nuclei REJECT nucleus. Must
be plural for M2.
M2 dep on mention of
electrons in M1

(b) (i) diamond 1

4
(ii) Any four from:

M1 graphite is giant covalent ALLOW giant structure

if M2 is scored
REJECT molecules of
graphite

M2 (in melting graphite) covalent bonds are ALLOW description of

broken covalent bonds

M3 (C60) (simple) molecular structure ALLOW molecules of C60

M4 (in melting C60) intermolecular forces (of ALLOW breaking bonds

attraction) are overcome in C60 if intermolecular
forces clearly
mentioned
M4 subsumes M3

M5 more energy is needed to break covalent bonds

(in graphite) than intermolecular forces (in C60)

Mention of
intermolecular forces in
graphite no M2 or M5
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Mention of breaking

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M4 or M5

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Total for question = 9 marks

Question
Answer Notes Marks
number
11 (a) (i) M1 add anhydrous copper sulfate ALLOW add white 2
copper sulfate

M2 turns (from white) to blue M2 dep on copper

sulfate in M1

ALLOW

M1 add anhydrous /
blue cobalt chloride

M2 turns (from blue) to

pink

M2 dep on cobalt
chloride in M1

(ii) M1 measure the boiling point / freezing point ALLOW boil it or freeze 2
it
M2 100 °C / 0°C
Value must match
property

(b) M1 mass of hydrated zinc sulfate = 54.46-41.64 OR 5

12.82 g

M2 Moles of hydrated zinc sulfate = 12.82÷287 OR ALLOW M1÷287

0.0447

M3 Moles H2O = 0.0447×7 OR 0.313 ALLOW M2×7

M4 Mass H2O = 5.63 g ALLOW M3×18

M5 Volume H2O 5.6 cm3 Must be 1dp

ALLOW M4 to 1dp

Correct answer of 5.6

cm3 to 1dp with or
without working scores
5 marks

(c) (i) 1.7 ALLOW 2 or more 1

significant figures
REJECT incorrect
rounding

(ii) M1 stand the measuring cylinder in a beaker of ice ALLOW any way of 2
cooling the measuring
OR
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cylinder or delivery

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tube

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M1 replace the delivery tube with a (Liebig)

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condenser ALLOW add a condenser

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IGNORE add a stopper /
bung

M2 less water / water vapour / steam lost ALLOW more water

(vapour) / steam
condenses
ALLOW less water
evaporates
Total for question = 12
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Pearson Education Limited. Registered company number 872828

with its registered office at 80 Strand, London, WC2R 0RL, United Kingdom