Kinetics: Edexcel International A Level Chemistry questions

Every Edexcel International A Level Chemistry exam question on 9A Kinetics (specification points 9.1–9.8), 2019–2025, with its mark scheme and examiner’s report.

All 70 questions on Kinetics, as a list

June 2025, AS Unit 2, Q9 (1 mark): In an experiment to measure the rate of reaction, a sample of magnesium ribbon, of mass 0.24 g, was added to 25 cm3 sulfuric acid, of concentration 1.00 mol dm–
June 2025, AS Unit 2, Q10 (1 mark): Which change increases the proportion of particles in a reaction that have sufficient energy to react? A an increase in reaction temperature B a decrease in rea
June 2025, AS Unit 2, Q14(a) (3 marks): Ammonia is produced in the Haber process. Nitrogen and hydrogen react at a pressure of 200 atmospheres and a temperature of 725 K, using an iron catalyst. Expla
January 2025, AS Unit 2, Q8(a) (1 mark): What is the approximate value of the initial rate of reaction? (1) A 4.5 × 10–5 B 1.8 × 10–5 C 1.3 × 10–5 D 2.0 × 10–6
January 2025, AS Unit 2, Q8(b) (1 mark): What are the units for the rate of reaction? (1) A mol s–1 B mol dm–3 s–1 C mol dm3 s–1 D dm3 mol–1 s Use this space for any rough working. Anything you write i
January 2025, AS Unit 2, Q17(b)(i) (1 mark): Complete the table. (1) Acidified (1 ÷ t) × 103 Rhubarb juice Deionised 1 ÷ t manganate(VII) Time (t) / s / cm3 water / cm3 / s–1 / s–1 / cm3 5 1 5 398 0.00251
January 2025, AS Unit 2, Q17(b)(ii) (4 marks): Plot a graph of the rate of reaction, as represented by (1 ÷ t) × 103 , against the volume of rhubarb juice. (4)
January 2025, AS Unit 2, Q17(b)(iii) (2 marks): Explain why a rate of reaction is greater at higher concentrations. (2)
January 2025, AS Unit 2, Q17(d)(i) (1 mark): Draw a curve to represent the distribution at a higher temperature. (1) Fraction of particles with a speciﬁc energy Energy Ea
January 2025, AS Unit 2, Q17(d)(ii) (3 marks): Explain why increasing the temperature increases the rate of reaction. (3)
January 2025, AS Unit 2, Q21(e)(ii) (2 marks): Many different catalysts have been used, including MoO3 , WO3 and Re. State two characteristics that all these catalysts have in common. (2)
October 2024, AS Unit 2, Q1(a) (1 mark): What happens to the curve when the temperature is increased? (1) A the peak becomes higher and further to the right B the peak becomes higher and further to the
October 2024, AS Unit 2, Q1(b) (1 mark): How does the diagram change if a catalyst is added? (1) A the activation energy moves to the right and the peak stays the same B the activation energy moves to
June 2024, AS Unit 2, Q15(a) (1 mark): For Container 2, the temperature is increased. For which values would the energy value change? (1) A Ea only B Emode only C Emode and Emean only D Ea , Emode an
June 2024, AS Unit 2, Q15(b) (1 mark): For Container 3, at the same temperature as Container 1, the pressure is lower. For which values would the number of particles at that value change? (1) A Ea on
June 2024, AS Unit 2, Q15(c) (1 mark): For Container 4, at the same temperature and pressure as Container 1, the walls of the container act as a catalyst for the reaction of the gas. For which values
June 2024 (R), AS Unit 2, Q1(a) (1 mark): Which letter represents the mean energy of the molecules? (1) A letter P B letter Q C letter R D letter S
June 2024 (R), AS Unit 2, Q1(b) (1 mark): What happens to the curve when the temperature is decreased? (1) A the peak becomes higher and further to the right B the peak becomes higher and further to the
June 2024 (R), AS Unit 2, Q3(a) (1 mark): Which change in property will not affect the rate of this reaction? (1) A concentration of hydrochloric acid B particle size of calcium carbonate C pressure of
June 2024 (R), AS Unit 2, Q3(b) (1 mark): The graph shows the results of one of the experiments. 120 100 80 Volume of carbon dioxide / cm3 60 40 20 0 0 20 40 60 80 100 120 Time / s What is the approxima
June 2024 (R), AS Unit 3, Q4(a) (2 marks): Justify an appropriate temperature for the water bath. (2)
June 2024 (R), AS Unit 3, Q4(c) (1 mark): State how the results of this experiment could be converted into a value that can be used as a measure of rate. (1)
January 2024, AS Unit 2, Q13 (1 mark): Which statement best explains why the rate of a chemical reaction increases with increasing temperature? A the activation energy decreases B the number of colli
January 2024, AS Unit 2, Q24(d) (4 marks): The industrial manufacture of ethanoic acid first used an iodine-based catalyst. Explain, with the aid of a labelled Maxwell–Boltzmann distribution, how a catal
January 2024, Unit 4, Q1(a) (1 mark): Some collisions between reactant molecules do not lead to the formation of products. What is the best explanation for this? (1) A the reactant concentrations ar
October 2023, AS Unit 2, Q21(b)(i) (3 marks): Explain how a catalyst increases the rate of this reaction. Use the Maxwell–Boltzmann distribution shown and refer to the collision theory. (3) Number of partic
October 2023, AS Unit 3, Q2(b) (2 marks): Explain why ethanoic acid is used and not hydrochloric acid. (2)
June 2023, AS Unit 2, Q14 (1 mark): In a series of experiments, the time taken to complete the reaction between iron(III) sulfate and sodium thiosulfate in aqueous solution is measured. One drop o
June 2023, AS Unit 2, Q15 (1 mark): Hydrogen peroxide decomposes in the presence of a catalyst. 2H2O2(aq) → 2H2O(l) + O2(g) The volume of gas formed is measured at regular time intervals and the d
June 2023, AS Unit 2, Q21(a)(i) (1 mark): On the diagram, sketch the Maxwell–Boltzmann distribution for this reaction mixture at a higher temperature. (1)
June 2023, AS Unit 2, Q21(a)(ii) (2 marks): Using the Maxwell–Boltzmann distributions, explain why increasing the temperature and adding a catalyst both increase the rate of reaction. (2)
June 2023, AS Unit 2, Q21(b) (2 marks): An alternative method for producing methanal uses a silver catalyst at a temperature of 650 °C. The reaction is shown. CH3OH(g) → HCHO(g) + H2(g) Suggest one ad
January 2023, AS Unit 2, Q17(a) (1 mark): Why does the distribution of energies start at the origin, (0,0)? (1) A some molecules have no energy B all molecules possess some energy C the temperature is 0
January 2023, AS Unit 2, Q17(b) (1 mark): Some of the gas is removed and then the container is resealed and the gas is cooled. How does the new distribution of molecular energies compare to the original
January 2023, AS Unit 2, Q22(d)(i) (3 marks): Complete the profile for the catalysed and uncatalysed reactions. Label the activation energies and the enthalpy change of reaction, ΔH. Your diagram must match
January 2023, AS Unit 2, Q22(d)(ii) (1 mark): Suggest why the use of the catalyst makes Stage 2 more sustainable. (1)
January 2023, AS Unit 2, Q22(e)(i) (1 mark): Give one reason why a high temperature is needed in this reaction. (1)
October 2022, AS Unit 2, Q16 (1 mark): The results of an experiment to determine the rate of the reaction between magnesium and hydrochloric acid are shown. 120 100 80 Volume of hydrogen / cm3 60 40
October 2022, AS Unit 2, Q17(a) (1 mark): Which statement is correct? (1) A position X represents the mean energy of the particles B activation energy, Ea , is the mean energy of the particles that reac
October 2022, AS Unit 2, Q17(b) (1 mark): What happens to the distribution curve when the temperature of the gas is decreased? (1) Position of the peak Height of the peak A shifts to the right lower B s
October 2022, AS Unit 2, Q21(a)(iii) (4 marks): Vanadium(V) oxide, V2O5 , is used to catalyse the reaction in Step 2. Complete the reaction profile to show both the catalysed and uncatalysed reactions. Label
October 2022, AS Unit 2, Q21(a)(iv) (2 marks): Explain how the use of a catalyst makes this reaction more sustainable. (2)
June 2022, AS Unit 2, Q10(a) (1 mark): A catalyst increases the rate of decomposition by (1) A increasing the average kinetic energy of the H2O2 molecules B decreasing the average kinetic energy of t
June 2022, AS Unit 2, Q15(b)(ii) (3 marks): The results of the student’s experiment are shown on the graph. 100 80 60 Volume of CO2 / cm3 40 20 0 0 120 240 360 480 600 Time / s Calculate the initial rate
June 2022, AS Unit 2, Q15(b)(iii) (1 mark): The student repeats the experiment but uses hydrochloric acid with a concentration of 0.250 mol dm−3 . All other variables are kept the same. State what would h
January 2022, AS Unit 2, Q24(f)(i) (1 mark): Explain why it is not correct to state that urea is acting as a catalyst in the reaction. (1)
January 2022, AS Unit 2, Q24(f)(ii) (3 marks): Explain how a catalyst increases the rate of a chemical reaction. Use the Maxwell‑Boltzmann distribution shown and refer to the collision theory. (3) Number of
January 2022, AS Unit 2, Q24(g)(i) (1 mark): Suggest how the catalytic converter reaches this temperature. (1)
October 2021, AS Unit 2, Q22(e)(ii) (4 marks): The rate of this reaction is increased by using a catalyst of phosphoric acid. Label the axes on the Maxwell–Boltzmann distribution curve and use it to explain
October 2021, AS Unit 2, Q22(f)(i) (1 mark): Suggest the advantage of using support materials containing lots of pores. (1)
October 2021, AS Unit 3, Q4(a)(i) (3 marks): Calculate the rate at 15 °C to a suitable number of significant figures. Include units in your answer. (3)
October 2021, AS Unit 3, Q4(a)(ii) (1 mark): Sketch a line showing how the rate of reaction varies with temperature for this reaction. (1) Rate Temperature
October 2021, AS Unit 3, Q4(c) (1 mark): State how you would change the conditions to make this chemical clock measure 40 s at 22 °C. (1)
June 2021, AS Unit 2, Q3 (1 mark): The graph shows how the concentration of iodine changes with time in a reaction. 0.30 0.25 0.20 [I2] 0.15 / mol dm–3 0.10 0.05 0.00 0 2 4 6 8 10 12 14 16 Time /
June 2021, AS Unit 2, Q4 (1 mark): The solid line on the graph below shows the Maxwell–Boltzmann distribution for an uncatalysed reaction. Ea is the activation energy of this reaction. X Number o
June 2021, AS Unit 2, Q22(e)(ii) (1 mark): In a closed bottle, the rate of this reaction decreases with time. Give a reason for this. (1)
January 2021, AS Unit 2, Q1 (1 mark): The energy profile for a reaction is shown. Y X Energy products reactants Progress of reaction What is the minimum energy needed for this reaction to occur? A X
January 2021, AS Unit 2, Q22(d)(ii) (4 marks): A student investigated the role of the catalyst in this reaction. Procedure Step 1 Heat a sample of KClO3 , in a test tube, with a known mass of insoluble cata
January 2021, AS Unit 2, Q22(e) (2 marks): Explain, using the diagram, how a catalyst speeds up a chemical reaction. (2) Number of particles with energy, E Energy, E
October 2020, AS Unit 2, Q5(b) (1 mark): In an experiment, the volume of oxygen produced by the decomposition of hydrogen peroxide was measured at various times as the reaction progressed and a graph w
October 2020, AS Unit 2, Q11(b) (1 mark): Which sketch graph shows the volume of carbon dioxide (y‑axis) plotted against time (x‑axis) during the reaction? (1) A B C D
October 2020, AS Unit 2, Q11(c) (1 mark): Which sketch graph shows the rate of the reaction (y‑axis) plotted against time (x‑axis) during the reaction? (1) A B C D
October 2020, AS Unit 2, Q17(a)(iii) (1 mark): Give a reason why using a catalyst to increase the rate makes the process more sustainable. (1)
January 2020, AS Unit 2, Q18(c)(i) (3 marks): Draw on the axes the Maxwell−Boltzmann distribution of molecular energies of the reactant gases, showing on your diagram the activation energies for the catalys
January 2020, AS Unit 2, Q18(c)(ii) (2 marks): Explain, using your diagram, why the addition of a catalyst changes the rate of the reaction. (2)
January 2020, AS Unit 2, Q18(d)(ii) (2 marks): Suggest why it is an advantage to carry out Reaction 1 at a high temperature. (2)
January 2020, AS Unit 3, Q4(b) (2 marks): Step 2 6.0 g of solid potassium bromide is ground up into a fine powder using a pestle and mortar. The powder is then added to the round-bottomed flask contain
June 2019, AS Unit 2, Q1 (1 mark): Calcium carbonate reacts with hydrochloric acid. CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g) Which factor does not affect the rate of this reaction? A con
June 2019, AS Unit 2, Q2 (1 mark): The rate of a reaction doubles for each 10 K increase in temperature. If the temperature of this reaction is increased from 298 K to 358 K the rate of the react
June 2019, AS Unit 2, Q17 (1 mark): The graph shows how the concentration of a reactant changes with time. e d Concentration c 0 0 b a Time Which expression gives the best estimate for the value o

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