Skip to content
Try on iPad

Chemical kinetics: WJEC A‑Level Chemistry questions

Every WJEC A-Level Chemistry exam question on 3.5 Chemical kinetics, 2016–2025, with its mark scheme and examiner’s report.

Find questions1,204
Calculations

1,204 questions

  1. Q1

    Summer 2025 · Unit 3

    1 mark3.5 Chemical kinetics
    The whole paper ↗
    Summer 2025 Unit 3, question 1: Complete the Arrhenius equation below. [1] k =

  2. Q8(b)(i)

    Summer 2025 · Unit 3

    1 mark3.5 Chemical kinetics
    The whole paper ↗
    Summer 2025 Unit 3, question 8(b)(i): One method of studying the rate of this reaction is by sampling and quenching. State how you would quench the samples. [1]

  3. Q8(b)(ii)

    Summer 2025 · Unit 3

    1 mark3.5 Chemical kinetics
    The whole paper ↗
    Summer 2025 Unit 3, question 8(b)(ii): The reaction is first order with respect to each reactant therefore second order overall. A student states that this means that successive half-life values for

  4. Q8(b)(iii)

    Summer 2025 · Unit 3

    8 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2025 Unit 3, question 8(b)(iii): A student follows the progress of the reaction at a temperature of 298 K. She obtains the results shown in the graph. _3 4.00 × 10 _3 3.50 × 10 _3 3.00 × 10 [Cl

  5. Q7(a)

    Summer 2024 · Unit 3

    1 mark3.5 Chemical kinetics
    The whole paper ↗
    Summer 2024 Unit 3, question 7(a): Complete the table to show the volume of deionised water that should be used in the final experiment. Give a reason for the value you have chosen. [1]

  6. Q7(b)

    Summer 2024 · Unit 3

    2 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2024 Unit 3, question 7(b): Find the order of reaction with respect to iodate(V) ions. Explain how you reached your conclusion. [2]

  7. Q7(c)

    Summer 2024 · Unit 3

    2 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2024 Unit 3, question 7(c): The reaction is fourth order overall. Suggest a rate equation for the reaction. [2]

  8. Q7(d)

    Summer 2024 · Unit 3

    1 mark3.5 Chemical kinetics
    The whole paper ↗
    Summer 2024 Unit 3, question 7(d): Suggest a rate determining step for the reaction. [1]

  9. Q9(b)(i)

    Summer 2023 · Unit 3

    1 mark3.5 Chemical kinetics
    The whole paper ↗
    Summer 2023 Unit 3, question 9(b)(i): Write a rate equation for this reaction. [1]

  10. Q9(b)(ii)

    Summer 2023 · Unit 3

    2 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2023 Unit 3, question 9(b)(ii): A student suggests studying this reaction using sampling and quenching with samples taken every 30 seconds for 5 minutes. Explain why this would not be an appro

  11. Q9(c)(i)

    Summer 2023 · Unit 3

    1 mark3.5 Chemical kinetics
    The whole paper ↗
    Summer 2023 Unit 3, question 9(c)(i): A second student decides to use colorimetry to study the rate of this reaction. Explain what the student should consider when choosing an appropriate wavelength

  12. Q9(c)(ii)

    Summer 2023 · Unit 3

    3 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2023 Unit 3, question 9(c)(ii): The value of the rate constant was measured at five different temperatures to attempt to find the activation energy. ln k = ln A −(Ea/RT) A graph was plotted of

  13. Q3(a)

    Summer 2022 · Unit 3

    1 mark3.5 Chemical kinetics
    The whole paper ↗
    Summer 2022 Unit 3, question 3(a): Write the rate equation for this reaction. [1]

  14. Q3(b)

    Summer 2022 · Unit 3

    1 mark3.5 Chemical kinetics
    The whole paper ↗
    Summer 2022 Unit 3, question 3(b): Suggest a rate-determining step for this reaction. [1]

  15. Q11(b)(i)

    Summer 2022 · Unit 3

    4 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2022 Unit 3, question 11(b)(i): I. Find the orders of reaction with respect to chlorate(V) and bromide ions. [2] You must show your working. Order with respect to chlorate(V) ions Order with r

  16. Q11(b)(ii)

    Summer 2022 · Unit 3

    3 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2022 Unit 3, question 11(b)(ii): Chemists often use an approximate rule that the rate of a reaction doubles when the temperature is increased by 10 °C. Show that this rule is true if this react

  17. Q10(a)(i)

    Summer 2019 · Unit 3

    2 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2019 Unit 3, question 10(a)(i): Write the rate equation for this reaction. [2]

  18. Q10(a)(ii)

    Summer 2019 · Unit 3

    3 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2019 Unit 3, question 10(a)(ii): 5.62 × 1012 mol–1 dm3 s–1. Find the temperature used for this reaction. [3] T = K

  19. Q10(b)(i)

    Summer 2019 · Unit 3

    2 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2019 Unit 3, question 10(b)(i): Explain what is meant by the term ‘quenching’ and why it needs to be carried out. [2]

  20. Q10(b)(i)

    Summer 2018 · Unit 3

    3 marks3.5 Chemical kinetics
    The whole paper ↗
    Summer 2018 Unit 3, question 10(b)(i): Find the rate equation for this reaction. [3]
All 29 questions on Chemical kinetics, as a list
  1. Summer 2025, Unit 3, Q1 (1 mark): Complete the Arrhenius equation below. [1] k =
  2. Summer 2025, Unit 3, Q8(b)(i) (1 mark): One method of studying the rate of this reaction is by sampling and quenching. State how you would quench the samples. [1]
  3. Summer 2025, Unit 3, Q8(b)(ii) (1 mark): The reaction is first order with respect to each reactant therefore second order overall. A student states that this means that successive half-life values for
  4. Summer 2025, Unit 3, Q8(b)(iii) (8 marks): A student follows the progress of the reaction at a temperature of 298 K. She obtains the results shown in the graph. _3 4.00 × 10 _3 3.50 × 10 _3 3.00 × 10 [Cl
  5. Summer 2024, Unit 3, Q7(a) (1 mark): Complete the table to show the volume of deionised water that should be used in the final experiment. Give a reason for the value you have chosen. [1]
  6. Summer 2024, Unit 3, Q7(b) (2 marks): Find the order of reaction with respect to iodate(V) ions. Explain how you reached your conclusion. [2]
  7. Summer 2024, Unit 3, Q7(c) (2 marks): The reaction is fourth order overall. Suggest a rate equation for the reaction. [2]
  8. Summer 2024, Unit 3, Q7(d) (1 mark): Suggest a rate determining step for the reaction. [1]
  9. Summer 2023, Unit 3, Q9(b)(i) (1 mark): Write a rate equation for this reaction. [1]
  10. Summer 2023, Unit 3, Q9(b)(ii) (2 marks): A student suggests studying this reaction using sampling and quenching with samples taken every 30 seconds for 5 minutes. Explain why this would not be an appro
  11. Summer 2023, Unit 3, Q9(c)(i) (1 mark): A second student decides to use colorimetry to study the rate of this reaction. Explain what the student should consider when choosing an appropriate wavelength
  12. Summer 2023, Unit 3, Q9(c)(ii) (3 marks): The value of the rate constant was measured at five different temperatures to attempt to find the activation energy. ln k = ln A −(Ea/RT) A graph was plotted of
  13. Summer 2022, Unit 3, Q3(a) (1 mark): Write the rate equation for this reaction. [1]
  14. Summer 2022, Unit 3, Q3(b) (1 mark): Suggest a rate-determining step for this reaction. [1]
  15. Summer 2022, Unit 3, Q11(b)(i) (4 marks): I. Find the orders of reaction with respect to chlorate(V) and bromide ions. [2] You must show your working. Order with respect to chlorate(V) ions Order with r
  16. Summer 2022, Unit 3, Q11(b)(ii) (3 marks): Chemists often use an approximate rule that the rate of a reaction doubles when the temperature is increased by 10 °C. Show that this rule is true if this react
  17. Summer 2019, Unit 3, Q10(a)(i) (2 marks): Write the rate equation for this reaction. [2]
  18. Summer 2019, Unit 3, Q10(a)(ii) (3 marks): 5.62 × 1012 mol–1 dm3 s–1. Find the temperature used for this reaction. [3] T = K
  19. Summer 2019, Unit 3, Q10(b)(i) (2 marks): Explain what is meant by the term ‘quenching’ and why it needs to be carried out. [2]
  20. Summer 2018, Unit 3, Q10(b)(i) (3 marks): Find the rate equation for this reaction. [3]
  21. Summer 2018, Unit 3, Q10(b)(ii) (2 marks): Calculate the value of the rate constant, k, for this reaction. [2] k =
  22. Summer 2018, Unit 3, Q10(b)(iii) (2 marks): A student suggests that the rate determining step for this reaction is: Fe3+ + Sn2+ Fe2+ + Sn3+ State, giving a reason, whether this is a possible rate determin
  23. Summer 2018, Unit 3, Q10(c)(i) (1 mark): Explain what is meant by sampling and quenching. [1]
  24. Summer 2018, Unit 3, Q11(b)(i) (1 mark): State the Arrhenius equation. [1]
  25. Summer 2018, Unit 3, Q11(b)(ii) (3 marks): Calculate the activation energy using this catalyst and hence state whether it is a more effective catalyst than MnO2. [3] Activation energy = kJ mol–1
  26. Summer 2017, Unit 3, Q5(a) (1 mark): Complete the table with appropriate values of mean time taken. [1]
  27. Summer 2017, Unit 3, Q5(b) (1 mark): Calculate the rate of reaction for these two concentrations. [1] Rate for 0.200 mol dm−3 [I−] = s−1 Rate for 0.400 mol dm−3 [I−] = s−1
  28. Summer 2017, Unit 3, Q12(d) (3 marks): using the same concentrations and volumes of all other reactants. The following data were collected. Rate / mol dm−3 s−1 pH 3.287 × 10−3 1.0 1.308 × 10−3 1.4 5.
  29. Summer 2017, Unit 3, Q12(e) (4 marks): The value of the rate constant, k, for this reaction at two temperatures is given below. Temperature / K Rate constant (unit not shown) 288 0.0761 300 0.2873 Th

Questions, mark schemes and examiner’s reports are © WJEC CBAC Ltd, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? Every WJEC A-Level Chemistry paper.

Rather write your answers by hand on iPad? Plumi marks them against the same mark schemes.