PMT

Mark Scheme (Results)

January 2023

Pearson Edexcel International GCSE in

Chemistry (4CH1)
Paper 1C
 PMT

Edexcel and BTEC Qualifications

Edexcel and BTEC qualifications are awarded by Pearson, the UK’s largest awarding body. We
provide a wide range of qualifications including academic, vocational, occupational and specific
programmes for employers. For further information visit our qualifications websites at
www.edexcel.com or www.btec.co.uk. Alternatively, you can get in touch with us using the details
on our contact us page at www.edexcel.com/contactus.

Pearson: helping people progress, everywhere

Pearson aspires to be the world’s leading learning company. Our aim is to help everyone progress
in their lives through education. We believe in every kind of learning, for all kinds of people,
wherever they are in the world. We’ve been involved in education for over 150 years, and by
working across 70 countries, in 100 languages, we have built an international reputation for our
commitment to high standards and raising achievement through innovation in education. Find out
more about how we can help you and your students at: www.pearson.com/uk

January 2023
Question Paper Log Number P71892A
Publications Code 4CH1_1C_MS_2301
All the material in this publication is copyright
© Pearson Education Ltd 2023
 PMT

General Marking Guidance

 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.
 PMT

Question
Answer Notes Marks
number
1 (a) (i) particles should be close together and should fill ALLOW particles filling 1
from the bottom of the box, most particles should the whole box
touch with a minimum of 2 random rows of
particles IGNORE the size of the
particles

REJECT a regular
arrangement

(ii) solid 1

(b) solid to liquid melting 2

solid to gas sublimation ALLOW subliming

(c) An explanation that links the two points. 2

M1 (particles / molecules have) more (kinetic) ALLOW hot water has

energy more (kinetic) energy

ALLOW (particles /
molecules) move
faster

IGNORE vibrate more

M2 can overcome / break the (intermolecular) ALLOW can overcome /

forces/forces (between water molecules) break the bonds
(between water
molecules) OR
to break away from one
another OR to escape
more easily

IGNORE references to
collisions, activation
energy or rate of
reaction

Total for question = 6

 PMT

Question
Answer Notes Marks
number
2 (a) B (Cl2) 1

A is not the correct answer as the symbol O is for

atoms of oxygen not molecules
C is not the correct answer as HCl is a compound
D is not the correct answer as H2O is a compound

(b) C (filtration) 1

A is not the correct answer as crystallisation is not

used to separate an insoluble solid from a liquid
B is not the correct answer as evaporation will not
separate an insoluble solid from a liquid
D is not the correct answer as simple distillation is
used to separate a solvent from a solution

(c) fractional distillation REJECT distillation 1

REJECT simple distillation

(d) (i) D (X(s) → X(aq)) 1

A is not the correct answer as (l) is not the correct

final state symbol
B is not the correct answer as (g) Is not the final
state symbol
C is not the correct answer as the state symbols are
the wrong way round

(ii) C (diffusion) 1

A is not the correct answer as boiling does not

occur in the beaker
B is not the correct answer as condensing does not
occur in the beaker
D is not the correct answer as sublimation does not
occur in the beaker

(iii) M1 potassium / K+ potassium sulfate scores 2 2

M2 sulfate / SO42- K2SO4 scores 2

KSO4 alone scores 1

ALLOW in either order

If name correct ignore

incorrect formula

Total for question = 7

 PMT

Question
Answer Notes Marks
number
3 (a) (i) argon / Ar 1

(ii) C (nitrogen) 1

A is not correct because nitrogen is more abundant

than carbon dioxide methane or oxygen
B is not correct because nitrogen is more abundant
than methane
D is not correct because nitrogen is more abundant
than oxygen

(b) (i) (hydrated) iron (III) oxide REJECT other oxidation 1

states

ALLOW Fe2O3

IGNORE iron oxide

(ii) (neon) has a full outer shell (of electrons) ALLOW (neon) is 1
unreactive / inert /has 8
electrons in the outer
shell

ALLOW (neon) does not

lose or gain (or share)
electrons

(iii) M1 75  30 OR 45 (mm) 2

M2 (45 ÷ 75 × 100) = 60(%) ALLOW ecf from M1

correct answer of 60%

without working scores 2

answer of 40% without

working scores 1

Total for question = 6

 PMT

Question
Answer Notes Marks
number
4 (a) 4
M1 baseline has been drawn in ink ALLOW baseline is not
drawn in pencil

M2 and will therefore interfere with / contaminate ALLOW will move up the
the results paper / will get mixed
up with A / will produce
other colours /affect
results / will smudge
/ink is soluble

M3 the water level is above A/the baseline ALLOW water level is

too high / A is under
water

M4 and therefore A will mix with/dissolve in the ALLOW A will wash off
water the paper

IGNORE references to
lid

(b) (i) M1 one spot about ¼ of the way between the ALLOW answers that 2
baseline and the top of the paper / solvent front show solvent front
and one spot about ½ way

M2 the lower spot labelled yellow and the higher

spot labelled blue

(ii) the blue food colouring/it is more soluble (in water) 1

ORA as long as yellow food colouring is referred to IGNORE blue colour/it
travels further up the
paper

Total for question = 7

 PMT

Question
Answer Notes Marks
number
5 (a) (i) copper ALLOW Cu 1

REJECT copper(II) /Cu2+

(ii) magnesium cannot displace itself ALLOW magnesium does 1

not react with
magnesium sulfate
/magnesium ions /Mg2+

IGNORE magnesium
does not react with
magnesium /itself

(b) (i) magnesium /Mg ALLOW 1 mark if 2

aluminium /Al aluminium and X are
X swapped.
copper /Cu

If copper(II) instead of
copper 1 mark only

(ii) zinc / iron ALLOW all other valid 1

answers

(c) An explanation that links the two points 2

M1 magnesium /Mg (is the reducing agent)

M2 magnesium /Mg donates electrons (causing Al 3+ ALLOW magnesium / Mg

ions to be reduced) gives (away) / loses
electrons (causing Al3+
to be reduced) /Al3+
gains electrons

No M2 if reference to
aluminium/Al instead of
aluminium ions/Al3+

IGNORE Mg is oxidised

M2 dep on M1
Total for question = 7 marks
 PMT

Question
Answer Notes Marks
number
6 (a) B (chloroethene) 1

A is not correct as the monomer has a double bond

C is not correct as the monomer has two carbons
D is not correct as the monomer has two carbons

(b) 1
Extension bonds do not
need to go through the
brackets

(c) M1 (Mr of chloroethene) = 62.5 2

M2 2490000 ÷ 62.5 = 39 840

(d) A discussion which refers to any 4 of the following 4

points

M1 polymers/poly(propene) will remain in landfill ALLOW reference to

indefinitely OWTTE running out of landfill
sites OWTTE

M2 (as they) are inert /unreactive/do not

biodegrade/do not decompose

M3 burning produces greenhouse gases / CO2

M4 reference to climate change /global warming

M5 burning produces toxic gases ALLOW carbon

monoxide /CO
/hydrogen chloride/HCl

Max 3 if any reference

to the ozone layer

(e) M1 1:1:3 / 31 800 ÷ 10 600 ALLOW other evidence 2

of working

M2 CHCl3 ALLOW the atoms in any

order

Answer of CHCl3 without

working scores 2

Total for question = 10

 PMT

Question
Answer Notes Marks
number
7 (a) X contains oxygen /OH ALLOW hydrocarbons 1
only contain hydrogen
and carbon (atoms)

REJECT oxygen
molecules or hydrogen
and carbon molecules

(b) W 1

(c) V 1

(d) CH2=CHCH2CH3 ALLOW CH2CHCH2CH3 1

(e) M1 same molecular formula ALLOW same numbers 2

of C and H atoms

M2 different displayed / structural formulae ALLOW different

arrangement of atoms

(f) (i) C4H10 + Br2 → C4H9Br + HBr 2

M1 C4H9Br as product ALLOW polysubstitution

M2 rest of the equation correct M2 dep on M1

(ii) C (substitution) 1

A is not the correct answer because alkanes do not

undergo addition reactions
B is not the correct answer as this is not a
combustion reaction
D is not the correct answer as this reaction is not
thermal decomposition

(g) A description that refers to any 3 from 3

M1 nitrogen and oxygen (from air) REJECT mention of

petrol contains nitrogen
for M1 only

M2 react at the high temperatures (in a car M2 dep on mention of

engine) nitrogen and oxygen

M3 forming oxides of nitrogen ALLOW NOx or named

oxides of nitrogen

M4 which react with/dissolve in water forming M4 dep on M3

nitric acid /HNO3 /acid rain
Total for question = 12
 PMT

Question
Answer Notes Marks
number
8 (a) (i) M1 NaCl Penalise once only for 3
incorrect case or
M2 MgCl2 superscript numbers

M3 Mg3N2 ALLOW symbols

reversed e.g. N2Mg3

ALLOW correct charges

on ions e.g Mg2+(Cl-)2

(ii) magnesium oxide Spelling must be 1

correct
(iii) 83 IGNORE units 1

(b) (i) M1 lithium changes (from 2.1) to 2 ALLOW (two) lithium 2

(atoms) lose one
electron

M2 oxygen changes (from 2.6) to 2.8 ALLOW oxygen (atom)

gains two electrons

No marks if mention of
sharing electrons

(ii) An explanation that links the three points 3

M1 strong (electrostatic) forces of attraction ALLOW strong ionic

bonds

M2 between oppositely charged ions

M3 which require a lot of energy to break IGNORE more energy

0 marks if any mention

of covalent bonds,
intermolecular forces or
molecules

Total for question = 10

 PMT

Question
Answer Notes Marks
number
9 (a) M1 (electrostatic) attraction between nuclei must be plural 2

M2 and shared pair(s) of electrons

OR

M1 (electrostatic) attraction between shared pair(s)

of electrons

M2 and nuclei must be plural

(b) An explanation that links any 3 from 3

M1 the boiling points increase (down the

group/from F to Br)

M2 because the intermolecular forces get stronger

M3 as (molecular) mass / size / number of electrons

/(electron) shells increases

M4 so more energy needed to separate the

molecules/break the intermolecular forces No M2, M3 or M4 if any
mention of breaking
covalent/ionic bonds

(c) An explanation that links any five from 5

M1 the structure is in layers ALLOW sheets /rows

M2 there are weak forces between the layers (of REJECT intermolecular
atoms) forces/molecules/ions

M3 which can slide (over one another making it

soft)

M4 each carbon / atom makes three covalent bonds REJECT ionic bonds

M5 (one) delocalised electron (per carbon / atom) REJECT molecules/ions

M6 (delocalised) electrons flow / move / are mobile

(to conduct electricity)

Total for question = 10

 PMT

Question
Answer Notes Marks
number
10 (a) (i) measuring cylinder ALLOW burette / 1
pipette /syringe

REJECT gas syringe

(b) (i) M1 Q = m × c × ΔT 4

M2 ΔT = 2880 ÷ (50 × 4.2) M2 subsumes M1

M3 ΔT = 13.7(1) °C

M4 (maximum temp = 13.7(1) + 21.(0) =) 34.7 (°C) ALLOW ecf from M3

ALLOW any number of

sig fig except 1 in M3
and M4

Correct answer without

working scores 4

(b) (ii) thermal energy/heat lost (to the atmosphere / IGNORE energy lost 1
surroundings)

(b) (iii) M1 2880 ÷ 1000 OR 2.880 kJ 3

M2 2.880 ÷ 0.05(00) ALLOW ecf from M1

M3 -57.6kJ/mol ALLOW any number of

sig fig except 1 in M3
OR

M1 2880 ÷ 0.05(00) OR 57 600J

M2 57 600 ÷ 1000 ALLOW ecf from M1

M3 -57.6 kJ/mol ALLOW any number of

sig fig except 1 in M3

Correct answer without

working scores 3

Total for question = 9

 PMT

Question
Answer Notes Marks
number
11 (a) (i) M1 so all the nitric acid reacts/is neutralised 2

AND

M2 therefore the solution only contains magnesium ALLOW so the excess

nitrate magnesium can be
removed by filtration
OR

M3 if acid is still present it will contaminate the

crystals OWTTE

(ii) M1 moles of Mg that reacts = 0.0250 ÷ 2 OR 0.0125 3

M2 mass of Mg that reacts = 0.0125 x 24 OR 0.3 (g) ALLOW M1 × 24

M3 mass of Mg remaining = 0.45 (g) ALLOW 0.75 - M2

OR

M1 moles of Mg = 0.0250 ÷ 2 OR 0.0125

M2 moles of Mg remaining = 0.75 ÷ 24  0.0125 OR ALLOW 0.03125  M1

0.03125  0.0125 OR 0.01875

M3 mass of Mg remaining (= 0.01875 x 24) = 0.45 (g) ALLOW M2 x 24

Correct answer without

working scores 3

0.15 (g) scores 2

(iii) M1 filter off the excess magnesium 5

M2 heat the solution until crystals first start to form ALLOW heat until the
solution is saturated
/ heat until crystals form
on the end of a glass rod
/heat to evaporate some
of the water
M3 leave the solution to cool (and crystallise)

M4 pour/filter off excess liquid (to obtain crystals)

IGNORE washing

M5 leave (crystals) to dry ALLOW any method of

drying that avoids excess
heat e.g. filter paper, a
desiccator, a warm oven

If heated to dryness only

M1 can be scored

If solution is not heated

only M1, M4 and M5 can
be scored
 PMT

(b) M1 tangent drawn (at 40 s) 3

M2 change in volume of hydrogen ÷ change in time

M3 correct answer between 2.75 and 3.75 (cm3/s)

inclusive
If no tangent drawn allow
1 mark for
240 ÷ 40 = 6 (cm3/s)

Total for question = 13

 PMT

Question
Answer Notes Marks
number
12 (a) (i) to make sure all the water is given off/evaporates ALLOW to make sure 1
the reaction is
complete

(ii) 5.2(0 g) 1

(iii) 0.9(0 g) 1

(iv) M1 moles of BaCl2= 5.2 ÷ 208 OR 0.025 ALLOW ecf from (ii) 3

M2 moles of H2O = 0.9 ÷ 18 OR 0.05(0) ALLOW ecf from (iii)

M3 0.05(0) ÷ 0.025 = 2 ALLOW ecf from M1 and

M2 as long as the
answer is an integer

Correct answer without

working scores 3

(b) M1 (measure the) boiling point ALLOW freezing point 2

M2 100°C ALLOW 0°C for freezing

point

(c) (i) reversible ALLOW the reaction 1

goes in both directions

IGNORE equilibrium

(ii) M1 add water to anhydrous copper sulfate ALLOW white copper 2

sulfate

M2 which turns (from white) to blue M2 dep on mention of

anhydrous/white
copper sulfate

Max 1 mark if incorrect

starting colour

(iii) M1 moles of water = 0.02 x 5 OR 0.1 2

M2 molecules of water = 6 × 1022 ALLOW ecf from M1

Correct answer without

working scores 2

1.2 x 1022 scores 1

Total for question = 13

 PMT

Pearson Education Limited. Registered company number 872828

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