Please check the examination details below before entering your candidate information
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel International GCSE (9–1)
Friday 13 June 2025
Morning (Time: 1 hour 40 minutes) Paper
reference 4WCH2/1CR
Chemistry (Modular) 🟐 🟐
UNIT 2: 4WCH2
PAPER: 1CR
You must have: Total Marks
Calculator, ruler
Instructions
•• Use black ink or ball-point pen.
If pencil is used for diagrams/sketches/graphs it must be dark (HB or B).
• Fill in the
centre boxesand
number at the top of this
candidate page with your name,
number.
•• Answer
Answer all
thequestions.
questions in the spaces provided
• Show all the steps in the calculations and state the units where required.
– there may be more space than you need.
Information
•• The total mark for this paper is 90.
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
Write your answers neatly and in good English.
to answer every question.
Check your answers if you have time at the end.
Pearson Edexcel International Chemistry Modular (4WCH2/1CR)
Question Paper 1CR and Mark Scheme Summer 2025
, 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
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.
■■■■
, DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
■■■■
BLANK PAGE
Turn over
3
, Answer ALL questions.
Some questions must be answered with a cross in a box . If you change your mind about an
DO NOT WRITE IN THIS AREA
answer, put a line through the box and then mark your new answer with a cross .
1 This question is about catalysts.
(a) Complete the sentences by writing a suitable word in each blank space.
(3)
If a catalyst is added to a reaction mixture,
the rate of reaction is . .. .. .. .. .. .. . ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . ... .. .. .. .. .. .. .. .
The activation energy for the reaction is . . .. .. ... .. .. ... .. .. ... .. ... .. .. .. .. .. ... .. .. ... .. .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. . .
The amount of catalyst at the end of a reaction is . . ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... ... ... ... ... ... ... .. .
DO NOT WRITE IN THIS AREA
(b) A student investigates the effect of different catalysts on the rate of
decomposition of a hydrogen peroxide solution.
The table shows the time taken to produce the same volume of oxygen gas using
each catalyst.
Catalyst P Q R
Time in seconds 30 14 22
Give the letter of the catalyst that gives the fastest rate of reaction.
(1)
. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . ......................
DO NOT WRITE IN THIS AREA
4
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Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel International GCSE (9–1)
Friday 13 June 2025
Morning (Time: 1 hour 40 minutes) Paper
reference 4WCH2/1CR
Chemistry (Modular) 🟐 🟐
UNIT 2: 4WCH2
PAPER: 1CR
You must have: Total Marks
Calculator, ruler
Instructions
•• Use black ink or ball-point pen.
If pencil is used for diagrams/sketches/graphs it must be dark (HB or B).
• Fill in the
centre boxesand
number at the top of this
candidate page with your name,
number.
•• Answer
Answer all
thequestions.
questions in the spaces provided
• Show all the steps in the calculations and state the units where required.
– there may be more space than you need.
Information
•• The total mark for this paper is 90.
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
Write your answers neatly and in good English.
to answer every question.
Check your answers if you have time at the end.
Pearson Edexcel International Chemistry Modular (4WCH2/1CR)
Question Paper 1CR and Mark Scheme Summer 2025
, 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
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.
■■■■
, DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
■■■■
BLANK PAGE
Turn over
3
, Answer ALL questions.
Some questions must be answered with a cross in a box . If you change your mind about an
DO NOT WRITE IN THIS AREA
answer, put a line through the box and then mark your new answer with a cross .
1 This question is about catalysts.
(a) Complete the sentences by writing a suitable word in each blank space.
(3)
If a catalyst is added to a reaction mixture,
the rate of reaction is . .. .. .. .. .. .. . ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . ... .. .. .. .. .. .. .. .
The activation energy for the reaction is . . .. .. ... .. .. ... .. .. ... .. ... .. .. .. .. .. ... .. .. ... .. .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. . .
The amount of catalyst at the end of a reaction is . . ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... ... ... ... ... ... ... .. .
DO NOT WRITE IN THIS AREA
(b) A student investigates the effect of different catalysts on the rate of
decomposition of a hydrogen peroxide solution.
The table shows the time taken to produce the same volume of oxygen gas using
each catalyst.
Catalyst P Q R
Time in seconds 30 14 22
Give the letter of the catalyst that gives the fastest rate of reaction.
(1)
. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . .. . .. .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. .. . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . . ......................
DO NOT WRITE IN THIS AREA
4
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