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Rates of reaction: Eduqas A‑Level Chemistry questions

Every Eduqas A-Level Chemistry exam question on C2.3 Rates of reaction, 2016–2025, with its mark scheme and examiner’s report.

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1,513 questions

  1. Q3(a)

    June 2025 · Component 1

    1 markC2.3 Rates of reaction
    The whole paper ↗
    June 2025 Component 1, question 3(a): State how catalysts act to increase the rate of a chemical reaction. [1]

  2. Q3(b)

    June 2025 · Component 1

    1 markC2.3 Rates of reaction
    The whole paper ↗
    June 2025 Component 1, question 3(b): State what is meant by the term heterogeneous in this context. [1]

  3. Q4

    June 2025 · Component 1

    2 marksC2.3 Rates of reaction
    The whole paper ↗
    June 2025 Component 1, question 4: The graph below shows the volume of gas released during a chemical reaction. 60 50 40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 Time/s Calculate the initial rate

  4. Q5

    June 2025 · AS Component 2

    2 marksC2.3 Rates of reaction
    The whole paper ↗
    June 2025 AS Component 2, question 5: The diagram below shows the distribution of molecular energies for a sample of gas. Use this curve to explain how a catalyst increases the rate of reaction. [2

  5. Q10(a)

    June 2025 · AS Component 2

    6 marksC2.3 Rates of reaction
    The whole paper ↗
    June 2025 AS Component 2, question 10(a): Hydrogen peroxide, H2O2, decomposes slowly to give water and oxygen. 2H2O2(aq) 2H2O(I) + O2(g) If a catalyst such as manganese(IV) oxide is used, the rate of de

  6. Q10(b)

    June 2025 · AS Component 2

    2 marksC2.3 Rates of reaction
    The whole paper ↗
    June 2025 AS Component 2, question 10(b): State how the overall rate of decomposition would compare with the initial rate of decomposition. Explain your answer using particle theory.  [2]

  7. Q10(c)

    June 2025 · AS Component 2

    1 markC2.3 Rates of reaction
    The whole paper ↗
    June 2025 AS Component 2, question 10(c): State the type of catalyst used in this experiment. [1]

  8. Q10(d)

    June 2025 · AS Component 2

    3 marksC2.3 Rates of reaction
    The whole paper ↗
    June 2025 AS Component 2, question 10(d): Another student said that lead(IV) oxide is a more efficient catalyst. Briefly describe how the student could determine which is the better catalyst in the deco

  9. Q8

    June 2024 · Component 1

    1 markC2.3 Rates of reaction
    The whole paper ↗
    June 2024 Component 1, question 8: State the catalyst used in the contact process. [1]

  10. Q9(a)

    June 2024 · AS Component 2

    6 marksC2.3 Rates of reaction
    The whole paper ↗
    June 2024 AS Component 2, question 9(a): Sodium thiosulfate solution reacts with hydrochloric acid to produce a precipitate of sulfur. The equation for the reaction is shown below. Na2S2O3(aq) + 2HCI(a

  11. Q9(b)

    June 2024 · AS Component 2

    2 marksC2.3 Rates of reaction
    The whole paper ↗
    June 2024 AS Component 2, question 9(b): Use collision theory to explain why a change in concentration affects the rate of a reaction. [2]

  12. Q9(c)(i)

    June 2024 · AS Component 2

    1 markC2.3 Rates of reaction
    The whole paper ↗
    June 2024 AS Component 2, question 9(c)(i): Draw an arrow on the energy profile to show the activation energy for the backward reaction. [1]

  13. Q9(c)(ii)

    June 2024 · AS Component 2

    1 markC2.3 Rates of reaction
    The whole paper ↗
    June 2024 AS Component 2, question 9(c)(ii): State the effect of increasing the temperature on the rate of the backward reaction. Give a reason for your answer. [1]

  14. Q5(a)

    Autumn 2021 · Component 1

    1 markC2.3 Rates of reaction
    The whole paper ↗
    Autumn 2021 Component 1, question 5(a): Suggest a method of measuring the rate of this reaction.  [1]

  15. Q11(d)(v)

    Autumn 2021 · Component 1

    1 markC2.3 Rates of reaction
    The whole paper ↗
    Autumn 2021 Component 1, question 11(d)(v): The data in the table suggests that copper should react with chlorine at room temperature, however heating is usually needed for efficient reaction. Suggest why

  16. Q12(c)(ii)

    Autumn 2021 · Component 1

    3 marksC2.3 Rates of reactionC2.1 Simple equilibria and acid-base reactions
    The whole paper ↗
    Autumn 2021 Component 1, question 12(c)(ii): Equal volumes of 1.0 mol dm–3 solutions of HNO3, CH3COOH and H2SO4 were added to separate samples of 1 g of powdered magnesium carbonate. State and explain any

  17. Q14(a)

    Autumn 2021 · Component 1

    2 marksC2.3 Rates of reaction
    The whole paper ↗
    Autumn 2021 Component 1, question 14(a): Limestone is a common rock which consists mainly of calcium carbonate, but often contains dolomite [CaMg(CO3)2] as well as insoluble, inert impurities such as s

  18. Q12(a)(i)

    Autumn 2020 · Component 1

    1 markC2.3 Rates of reaction
    The whole paper ↗
    Autumn 2020 Component 1, question 12(a)(i): State what is meant by heterogeneous in this context. [1]

  19. Q12(a)(ii)

    Autumn 2020 · Component 1

    1 markC2.3 Rates of reaction
    The whole paper ↗
    Autumn 2020 Component 1, question 12(a)(ii): Give another example of a heterogeneous catalyst, clearly identifying the reaction that it catalyses. [1]

  20. Q11(a)(i)

    Autumn 2020 · AS Component 2

    1 markC2.3 Rates of reaction
    The whole paper ↗
    Autumn 2020 AS Component 2, question 11(a)(i): Its energy distribution curve at a certain temperature is shown below. On the same axes, draw another curve to show the distribution at a higher temperature. [1
All 64 questions on Rates of reaction, as a list
  1. June 2025, Component 1, Q3(a) (1 mark): State how catalysts act to increase the rate of a chemical reaction. [1]
  2. June 2025, Component 1, Q3(b) (1 mark): State what is meant by the term heterogeneous in this context. [1]
  3. June 2025, Component 1, Q4 (2 marks): The graph below shows the volume of gas released during a chemical reaction. 60 50 40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 Time/s Calculate the initial rate
  4. June 2025, AS Component 2, Q5 (2 marks): The diagram below shows the distribution of molecular energies for a sample of gas. Use this curve to explain how a catalyst increases the rate of reaction. [2
  5. June 2025, AS Component 2, Q10(a) (6 marks): Hydrogen peroxide, H2O2, decomposes slowly to give water and oxygen. 2H2O2(aq) 2H2O(I) + O2(g) If a catalyst such as manganese(IV) oxide is used, the rate of de
  6. June 2025, AS Component 2, Q10(b) (2 marks): State how the overall rate of decomposition would compare with the initial rate of decomposition. Explain your answer using particle theory.  [2]
  7. June 2025, AS Component 2, Q10(c) (1 mark): State the type of catalyst used in this experiment. [1]
  8. June 2025, AS Component 2, Q10(d) (3 marks): Another student said that lead(IV) oxide is a more efficient catalyst. Briefly describe how the student could determine which is the better catalyst in the deco
  9. June 2024, Component 1, Q8 (1 mark): State the catalyst used in the contact process. [1]
  10. June 2024, AS Component 2, Q9(a) (6 marks): Sodium thiosulfate solution reacts with hydrochloric acid to produce a precipitate of sulfur. The equation for the reaction is shown below. Na2S2O3(aq) + 2HCI(a
  11. June 2024, AS Component 2, Q9(b) (2 marks): Use collision theory to explain why a change in concentration affects the rate of a reaction. [2]
  12. June 2024, AS Component 2, Q9(c)(i) (1 mark): Draw an arrow on the energy profile to show the activation energy for the backward reaction. [1]
  13. June 2024, AS Component 2, Q9(c)(ii) (1 mark): State the effect of increasing the temperature on the rate of the backward reaction. Give a reason for your answer. [1]
  14. Autumn 2021, Component 1, Q5(a) (1 mark): Suggest a method of measuring the rate of this reaction.  [1]
  15. Autumn 2021, Component 1, Q11(d)(v) (1 mark): The data in the table suggests that copper should react with chlorine at room temperature, however heating is usually needed for efficient reaction. Suggest why
  16. Autumn 2021, Component 1, Q12(c)(ii) (3 marks): Equal volumes of 1.0 mol dm–3 solutions of HNO3, CH3COOH and H2SO4 were added to separate samples of 1 g of powdered magnesium carbonate. State and explain any
  17. Autumn 2021, Component 1, Q14(a) (2 marks): Limestone is a common rock which consists mainly of calcium carbonate, but often contains dolomite [CaMg(CO3)2] as well as insoluble, inert impurities such as s
  18. Autumn 2020, Component 1, Q12(a)(i) (1 mark): State what is meant by heterogeneous in this context. [1]
  19. Autumn 2020, Component 1, Q12(a)(ii) (1 mark): Give another example of a heterogeneous catalyst, clearly identifying the reaction that it catalyses. [1]
  20. Autumn 2020, AS Component 2, Q11(a)(i) (1 mark): Its energy distribution curve at a certain temperature is shown below. On the same axes, draw another curve to show the distribution at a higher temperature. [1
  21. Autumn 2020, AS Component 2, Q11(a)(ii) (2 marks): The energy profile for this reaction is shown below. Energy Reaction pathway I. Label the position that represents the transition state of the reaction. [1] II.
  22. Autumn 2020, AS Component 2, Q11(a)(iii) (1 mark): The activation energy of the forward reaction (Ef ) is 195 kJ mol–1 Calculate the activation energy of the reverse reaction (Eb ). [1] Eb = kJ mol–1
  23. Autumn 2020, AS Component 2, Q11(b)(i) (4 marks): Calculate the initial rate of the reaction from the graph and give its unit. Show your working. [4] Initial rate =
  24. Autumn 2020, AS Component 2, Q11(b)(ii) (2 marks): Suggest two ways in which the rate of this reaction could be measured. [2]
  25. Autumn 2020, AS Component 2, Q11(b)(iii) (3 marks): I. State how the graph shows that the rate decreases as the reaction proceeds. [1] II. Use collision theory to explain why the rate of the reaction decreases as
  26. Autumn 2020, AS Component 2, Q11(b)(iv) (1 mark): State why it is necessary to keep the temperature constant during this experiment. [1]
  27. June 2019, Component 1, Q4(a) (1 mark): The graph below shows the energy distribution of particles at a temperature of 298 K. Sketch the distribution at a higher temperature on the same axes. [1] Frac
  28. June 2019, Component 1, Q4(b) (1 mark): Use the diagram below to show how a catalyst can affect the number of particles with sufficient energy to react. [1] Fraction of molecules with energy E Ea Ener
  29. June 2019, Component 1, Q13(a)(i) (3 marks): Explain fully why a pressure of 200 atm is used for this reaction. [3]
  30. June 2019, Component 2, Q12(b)(i) (1 mark): State why the sulfuric acid acts as a catalyst in this reaction. [1]
  31. June 2019, AS Component 2, Q9(g) (1 mark): 2 Since the reaction is very slow, she was told to use aqueous iron(III) nitrate as a catalyst. It is an amber colour originally but turns a dark reddish-brown
  32. June 2019, AS Component 2, Q12(a) (4 marks): Plot the results for the experiment and draw a line of best fit. Label it A. [4]
  33. June 2019, AS Component 2, Q12(b) (2 marks): Use the graph to calculate the rate of reaction at 20 seconds in cm3 s–1. [2] Rate = cm3 s–1
  34. June 2019, AS Component 2, Q12(c) (2 marks): When he repeated the experiment, it took him 8 seconds to replace the bung in the tube and start the stopwatch after adding the magnesium. On the graph, sketch
  35. June 2019, AS Component 2, Q12(e) (2 marks): The rates of some reactions can be determined from the loss of mass over a period of time. However, the student said that he could not use this method as he onl
  36. June 2019, AS Component 2, Q12(f) (3 marks): He repeated the experiment using the same mass of magnesium and the same volume and concentration of acid, in order to collect 100 cm3 of hydrogen, but over a l
  37. June 2018, Component 1, Q10(a)(i) (6 marks): The Wacker process is used to produce ethanal from ethene. It is a reaction catalysed by a mixed catalyst containing chlorides of copper and palladium. The reac
  38. June 2018, AS Component 2, Q5 (2 marks): Explain how a catalyst speeds up a reaction. [2]
  39. June 2018, AS Component 2, Q6(a) (1 mark): On the grid, sketch the curve that would be obtained if the experiment were repeated at 60 °C with all other conditions being unchanged. Label this curve A. [1]
  40. June 2018, AS Component 2, Q6(b) (1 mark): On the grid, sketch the curve that would be obtained if the experiment were repeated using 2.00 mol dm–3 hydrochloric acid with all other conditions being uncha
  41. June 2018, AS Component 2, Q10(a) (1 mark): The student says that it would be better to make up a single batch containing the acid, thiosulfate, iodide and starch solutions in the correct proportions befo
  42. June 2018, AS Component 2, Q10(b) (4 marks): State two changes which could be made in order to improve the results in this experiment. Explain your reason in each case. [4]
  43. June 2018, AS Component 2, Q10(c) (1 mark): Give a reason why the peroxide is measured into a boiling tube first and not added directly to the flask from a burette. [1]
  44. June 2018, AS Component 2, Q10(d) (1 mark): Suggest a reason why the student did not carry out the procedure using 8.0 cm3 of hydrogen peroxide and 6.0 cm3 of water. [1]
  45. June 2018, AS Component 2, Q10(e)(i) (1 mark): State how the rate depends on the concentra
  46. June 2018, AS Component 2, Q10(e)(ii) (2 marks): Use the graph to find the time taken for the colour change to occur when she used 6.0 cm3 of hydrogen peroxide and 8.0 cm3 of water. [2] Time = s
  47. June 2018, AS Component 2, Q10(f) (2 marks): Suggest another method, not using sodium thiosulfate, by which the rate of this oxidation reaction could be measured. [2]
  48. June 2018, AS Component 2, Q10(g) (2 marks): Explain, using simple collision theory, why the rate of this reaction changes as the concentration of hydrogen peroxide changes. [2]
  49. June 2017, Component 1, Q10(c)(i) (3 marks): I. Explain why both catalyst mixtures are classified as heterogeneous catalysts. [1] II. The active components of the catalyst mixtures are CuO and Fe2O3. Expla
  50. June 2017, AS Component 2, Q5(a) (1 mark): On the axes below, sketch the energy profile for this reaction. Label the activation energy of the forward reaction. [1] Energy Extent of reaction
  51. June 2017, AS Component 2, Q5(b) (1 mark): On the same axes, sketch the energy profile for the uncatalysed reaction. Label this profile X. [1]
  52. June 2017, AS Component 2, Q11(a) (1 mark): Name the apparatus used to collect and measure the volume of the gas produced. [1]
  53. June 2017, AS Component 2, Q11(b) (2 marks): Suggest an experimental method other than measuring the volume of gas that would allow the rate of this reaction to be studied. [2]
  54. June 2017, AS Component 2, Q11(d) (2 marks): Adam plotted his results as follows. 100 90 80 70 60 50 40 30 20 10 0 0 1 2 3 4 5 6 7 8 9 10 Time (minutes) By drawing a tangent to the curve calculate the init
  55. June 2017, AS Component 2, Q11(e) (3 marks): He then repeated the experiment using 40 cm3 of 0.10 mol dm–3 hydrochloric acid. Sketch on the graph in (d) the curve he would expect to obtain. Explain any dif
  56. June 2017, AS Component 2, Q11(f) (1 mark): State one condition, other than temperature and pressure, which would need to be kept constant in this investigation. [1]
  57. June 2016, AS Component 2, Q4(a) (1 mark): On the same axes, draw another curve to show the distribution for the same sample of gas at a higher temperature. [1]
  58. June 2016, AS Component 2, Q4(b) (1 mark): Ea represents the activation energy. Explain what is meant by activation energy. [1]
  59. June 2016, AS Component 2, Q8(a) (4 marks): Draw a graph on the grid below to show these results. [4]
  60. June 2016, AS Component 2, Q8(b) (2 marks): Use the graph to find the time taken, in seconds, if the experiment had been carried out using 0.030 mol dm−3 sodium thiosulfate so
  61. June 2016, AS Component 2, Q8(c) (1 mark): Suggest another method that Beverly could have used to follow the rate of this reaction. [1]
  62. June 2016, AS Component 2, Q8(f) (1 mark): State why all experiments were carried out using the same total volume of liquid. [1]
  63. June 2016, AS Component 2, Q8(g) (2 marks): + H2O(I) Beverly is asked to investigate the effect of changing the concentration of sodium thiosulfate solution on the rate of reaction. She is given 1.00 mol
  64. June 2016, AS Component 2, Q8(h) (2 marks): Beverly broke the conical flask while rinsing it after experiment 4 and Gerard gave her a 250 cm3 conical flask for experiment 5. H

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