Please check the examination details below before entering your candidate information
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel Level 1/Level 2 GCSE (9–1)
Friday 13 June 2025
Morning (Time: 1 hour 10 minutes) Paper
reference 1SC0/2CH
Combined Science
PAPER 5
Higher Tier
You must have: Total Marks
Calculator, ruler, Periodic Table (enclosed)
, Answer ALL questions. Write your answers in the spaces provided.
Some questions must be answered with a cross in a box . If you change your mind about an
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
answer, put a line through the box and then mark your new answer with a cross .
1 When solutions P and Q are mixed together, a purple mixture forms.
This mixture slowly becomes colourless.
(a) A student pours 25 cm3 of solution P into a conical flask and then adds
25 cm3 of solution Q.
The student uses a beaker to measure out these volumes.
Name a piece of apparatus that could be used to measure these volumes
more accurately.
(1)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
(b) The student investigates this reaction using the apparatus shown in Figure 1.
The student measures the time taken for the cross to become visible.
The experiment is repeated at different temperatures.
eye
reaction mixture
paper with black cross
Figure 1
Figure 2 shows the results.
temperature in °C time in s
20 45
40 19
60 10
Figure 2
2
*P75517RRA0220*
, (i) The concentrations of the solutions are kept constant in each experiment.
State one other variable that should be kept constant.
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
(1)
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(ii) State, and explain in terms of particles, how the time taken for the cross to
become visible would change if a temperature of 80 °C was used.
(3)
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(c) The concentration of solution Q is 26.8 g dm–3.
Calculate the mass of solid Q present in 25 cm3 of solution Q.
mass of solid (g)
concentration (g dm–3) =
volume of solution (dm3 )
(2)
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mass of solid Q = .............................................. . . . . . . . . . . . . . . . . g
3
*P75517RRA0320* Turn over
, (d) The student repeats the experiment at 20 °C, with the addition of a catalyst.
Explain how the addition of a catalyst will affect the rate of reaction.
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
(2)
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(Total for Question 1 = 9 marks)
4
*P75517RRA0420*
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel Level 1/Level 2 GCSE (9–1)
Friday 13 June 2025
Morning (Time: 1 hour 10 minutes) Paper
reference 1SC0/2CH
Combined Science
PAPER 5
Higher Tier
You must have: Total Marks
Calculator, ruler, Periodic Table (enclosed)
, Answer ALL questions. Write your answers in the spaces provided.
Some questions must be answered with a cross in a box . If you change your mind about an
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
answer, put a line through the box and then mark your new answer with a cross .
1 When solutions P and Q are mixed together, a purple mixture forms.
This mixture slowly becomes colourless.
(a) A student pours 25 cm3 of solution P into a conical flask and then adds
25 cm3 of solution Q.
The student uses a beaker to measure out these volumes.
Name a piece of apparatus that could be used to measure these volumes
more accurately.
(1)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
(b) The student investigates this reaction using the apparatus shown in Figure 1.
The student measures the time taken for the cross to become visible.
The experiment is repeated at different temperatures.
eye
reaction mixture
paper with black cross
Figure 1
Figure 2 shows the results.
temperature in °C time in s
20 45
40 19
60 10
Figure 2
2
*P75517RRA0220*
, (i) The concentrations of the solutions are kept constant in each experiment.
State one other variable that should be kept constant.
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
(1)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................................................................................................................................................... . . . . . . . . . . . . . . . . . . . .
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(ii) State, and explain in terms of particles, how the time taken for the cross to
become visible would change if a temperature of 80 °C was used.
(3)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................................................................................................................................................... . . . . . . . . . . . . . . . . . . . .
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(c) The concentration of solution Q is 26.8 g dm–3.
Calculate the mass of solid Q present in 25 cm3 of solution Q.
mass of solid (g)
concentration (g dm–3) =
volume of solution (dm3 )
(2)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................................................................................................................................................... . . . . . . . . . . . . . . . . . . . .
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mass of solid Q = .............................................. . . . . . . . . . . . . . . . . g
3
*P75517RRA0320* Turn over
, (d) The student repeats the experiment at 20 °C, with the addition of a catalyst.
Explain how the addition of a catalyst will affect the rate of reaction.
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
(2)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
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(Total for Question 1 = 9 marks)
4
*P75517RRA0420*
