OCR SUMMER 2026
PREDICTED PAPER
A Level Chemistry A
H432/03 Unified chemistry
Time allowed: 2 hours 15 minutes
You must have:
• the Data Sheet for Chemistry A
You can use:
a scientific or graphical calculator
a ruler (cm/mm)
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 70.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 22 pages.
ADVICE
• Read each question carefully before you start your answer.
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Turn over
, 2
1 (a) Bromoethane, CH₃CH₂Br, undergoes hydrolysis when heated with aqueous
sodium hydroxide.
CH₃CH₂Br(aq) + OH⁻(aq) → CH₃CH₂OH(aq) + Br⁻(aq)
A student investigates the rate of this reaction by measuring the concentration of
OH⁻ at regular time intervals. The results are shown below.
Time (min) [OH⁻] / mol dm⁻³
0 0.100
5 0.072
10 0.052
15 0.037
20 0.027
(i) The reaction is first order with respect to both CH₃CH₂Br and OH⁻.
Write the rate equation for this reaction
................................................................................................................................... [1]
(ii) The initial concentration of CH₃CH₂Br was also 0.100 mol dm⁻³.
Calculate the initial rate of reaction at t = 0, given that the rate constant k =
0.0860 dm³ mol⁻¹ min⁻¹.
initial rate of reaction...................................... [2]
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, 3
(iii) Suggest why the rate of reaction decreases over time even though the rate
constant k remains unchanged.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
................................................................................................................................... [1]
(b) Bromoethane can be converted into butane-1,4-diol via a series of reactions.
Step 1: CH₃CH₂Br + KCN → CH₃CH₂CN + KBr
Step 2: CH₃CH₂CN + 2H₂ → CH₃CH₂CH₂NH₂
Step 3: The amine produced reacts further to eventually yield butane-1,4-diol,
HOCH₂CH₂CH₂CH₂OH.
(i) State the type of reaction occurring in Step 1 and identify the organic product
CH₃CH₂CN.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
................................................................................................................................... [2]
(ii) State the reagents and conditions required for Step 2.
...................................................................................................................................
................................................................................................................................... [1]
for more: tyrionpapers.com
PREDICTED PAPER
A Level Chemistry A
H432/03 Unified chemistry
Time allowed: 2 hours 15 minutes
You must have:
• the Data Sheet for Chemistry A
You can use:
a scientific or graphical calculator
a ruler (cm/mm)
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 70.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 22 pages.
ADVICE
• Read each question carefully before you start your answer.
for more: tyrionpapers.com
Turn over
, 2
1 (a) Bromoethane, CH₃CH₂Br, undergoes hydrolysis when heated with aqueous
sodium hydroxide.
CH₃CH₂Br(aq) + OH⁻(aq) → CH₃CH₂OH(aq) + Br⁻(aq)
A student investigates the rate of this reaction by measuring the concentration of
OH⁻ at regular time intervals. The results are shown below.
Time (min) [OH⁻] / mol dm⁻³
0 0.100
5 0.072
10 0.052
15 0.037
20 0.027
(i) The reaction is first order with respect to both CH₃CH₂Br and OH⁻.
Write the rate equation for this reaction
................................................................................................................................... [1]
(ii) The initial concentration of CH₃CH₂Br was also 0.100 mol dm⁻³.
Calculate the initial rate of reaction at t = 0, given that the rate constant k =
0.0860 dm³ mol⁻¹ min⁻¹.
initial rate of reaction...................................... [2]
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, 3
(iii) Suggest why the rate of reaction decreases over time even though the rate
constant k remains unchanged.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
................................................................................................................................... [1]
(b) Bromoethane can be converted into butane-1,4-diol via a series of reactions.
Step 1: CH₃CH₂Br + KCN → CH₃CH₂CN + KBr
Step 2: CH₃CH₂CN + 2H₂ → CH₃CH₂CH₂NH₂
Step 3: The amine produced reacts further to eventually yield butane-1,4-diol,
HOCH₂CH₂CH₂CH₂OH.
(i) State the type of reaction occurring in Step 1 and identify the organic product
CH₃CH₂CN.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
................................................................................................................................... [2]
(ii) State the reagents and conditions required for Step 2.
...................................................................................................................................
................................................................................................................................... [1]
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