GCSE
Chemistry A
H032/02: Depth in chemistry
AS Level
*1442692574*
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 24 pages.
ADVICE
• Read each question carefully before you start your answer.
© OCR 2025 [601/5256/4] DC (PQ/CT) 350904/4
OCR is an exempt Charity
Turn over
1 A student is investigating the enthalpy change of neutralisation for a strong acid and a
strong alkali.
(a) Explain what is meant by an alkali.
........................................................................................................................................
..................
........................................................................................................................................
............. [1]
(b) Write the ionic equation for the neutralisation reaction between an acid and an alkali.
........................................................................................................................................
............. [1]
, 2
(c) The student mixes 40.0 cm of 1.40 mol dm–3 HCl and 40.0 cm3 of 1.40 mol dm–3
3
NaOH.
The temperature rises by 9.40 °C
(i) Calculate the enthalpy change of neutralisation, in kJ mol–1.
Give your answer to 3 significant figures.
Assume that the density of all solutions and the specific heat capacity, c, of the
reaction mixture is the same as for water.
Enthalpy change of neutralisation = ........................................... kJ mol–1 [4] (ii) The
student repeats the experiment using the same volume and concentration of NaOH but
using 20.0 cm3 of 2.80 mol dm–3 HCl instead of 40.0 cm3 of 1.40 mol dm–3 HCl .
The temperature rise is greater than 9.4 °C.
Explain why.
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© OCR 2025
, 3
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© OCR 2025 Turn over
, 4
2 This question is about reactions of some Group 2 elements and their compounds.
(a) The table below shows the first and second ionisation energies of magnesium and
calcium.
1st Ionisation 2nd Ionisation
Group 2 element energy / kJ energy / kJ
mol–1 mol–1
Mg 738 1451
Ca 590 1145
(i) Write an equation to represent the second ionisation energy of calcium.
Include state symbols.
........................................................................................................................................
............. [1]
(ii) * Magnesium and calcium differ in their reactivity.
Give a balanced equation for the reaction of calcium with water and describe what
would be observed. Explain why this is a redox reaction.
Explain the difference in reactivity of magnesium and calcium.
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© OCR 2025
Chemistry A
H032/02: Depth in chemistry
AS Level
*1442692574*
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 24 pages.
ADVICE
• Read each question carefully before you start your answer.
© OCR 2025 [601/5256/4] DC (PQ/CT) 350904/4
OCR is an exempt Charity
Turn over
1 A student is investigating the enthalpy change of neutralisation for a strong acid and a
strong alkali.
(a) Explain what is meant by an alkali.
........................................................................................................................................
..................
........................................................................................................................................
............. [1]
(b) Write the ionic equation for the neutralisation reaction between an acid and an alkali.
........................................................................................................................................
............. [1]
, 2
(c) The student mixes 40.0 cm of 1.40 mol dm–3 HCl and 40.0 cm3 of 1.40 mol dm–3
3
NaOH.
The temperature rises by 9.40 °C
(i) Calculate the enthalpy change of neutralisation, in kJ mol–1.
Give your answer to 3 significant figures.
Assume that the density of all solutions and the specific heat capacity, c, of the
reaction mixture is the same as for water.
Enthalpy change of neutralisation = ........................................... kJ mol–1 [4] (ii) The
student repeats the experiment using the same volume and concentration of NaOH but
using 20.0 cm3 of 2.80 mol dm–3 HCl instead of 40.0 cm3 of 1.40 mol dm–3 HCl .
The temperature rise is greater than 9.4 °C.
Explain why.
........................................................................................................................................
..................
........................................................................................................................................
..................
© OCR 2025
, 3
........................................................................................................................................
..................
........................................................................................................................................
..................
........................................................................................................................................
..................
........................................................................................................................................
..................
........................................................................................................................................
............. [2]
© OCR 2025 Turn over
, 4
2 This question is about reactions of some Group 2 elements and their compounds.
(a) The table below shows the first and second ionisation energies of magnesium and
calcium.
1st Ionisation 2nd Ionisation
Group 2 element energy / kJ energy / kJ
mol–1 mol–1
Mg 738 1451
Ca 590 1145
(i) Write an equation to represent the second ionisation energy of calcium.
Include state symbols.
........................................................................................................................................
............. [1]
(ii) * Magnesium and calcium differ in their reactivity.
Give a balanced equation for the reaction of calcium with water and describe what
would be observed. Explain why this is a redox reaction.
Explain the difference in reactivity of magnesium and calcium.
........................................................................................................................................
..................
........................................................................................................................................
..................
........................................................................................................................................
..................
........................................................................................................................................
..................
........................................................................................................................................
..................
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..................
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..................
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© OCR 2025
