Rates of reaction: Edexcel GCSE Combined Science questions

Every Edexcel GCSE Combined Science exam question on Rates of reaction (specification points 7.1–7.8), 2018–2025, with its mark scheme and examiner’s report.

All 90 questions on Rates of reaction, as a list

June 2025, Chemistry Paper 2 Higher, Q1(a) (1 mark): A student pours 25 cm3 of solution P into a conical flask and then adds 25 cm3 of solution Q. The student uses a beaker to measure out these volumes. Name a pie
June 2025, Chemistry Paper 2 Higher, Q1(b)(i) (1 mark): The concentrations of the solutions are kept constant in each experiment. State one other variable that should be kept constant. (1)
June 2025, Chemistry Paper 2 Higher, Q1(b)(ii) (3 marks): State, and explain in terms of particles, how the time taken for the cross to become visible would change if a temperature of 80 °C was used. (3)
June 2025, Chemistry Paper 2 Higher, Q1(d) (2 marks): The student repeats the experiment at 20 °C, with the addition of a catalyst. Explain how the addition of a catalyst will affect the rate of reaction. (2)
June 2025, Chemistry Paper 2 Higher, Q6(a) (1 mark): In an experiment, hydrochloric acid is reacted with zinc. The volume of gas produced is measured by collecting the gas in an upturned measuring cylinder over wa
June 2025, Chemistry Paper 2 Foundation, Q5(a) (1 mark): A student pours 25 cm3 of solution P into a conical flask and then adds 25 cm3 of solution Q. The student uses a beaker to measure out these volumes. Name a pie
June 2025, Chemistry Paper 2 Foundation, Q5(b)(i) (1 mark): The concentrations of the solutions are kept constant in each experiment. State one other variable that should be kept constant. (1)
June 2025, Chemistry Paper 2 Foundation, Q5(b)(ii) (3 marks): State, and explain in terms of particles, how the time taken for the cross to become visible would change if a temperature of 80 °C was used. (3)
June 2025, Chemistry Paper 2 Foundation, Q5(d) (2 marks): The student repeats the experiment at 20 °C, with the addition of a catalyst. Explain how the addition of a catalyst will affect the rate of reaction. (2)
June 2025, Chemistry Paper 2 Foundation, Q5(e)(i) (1 mark): Use a word or phrase from the box to complete the sentence about the mass of the catalyst in a reaction. (1) stays the same increases decreases During a reactio
June 2025, Chemistry Paper 2 Foundation, Q5(e)(ii) (2 marks): Complete the balanced equation for this reaction and add the missing state symbol. (2) H2O2(aq) → 2H2O( ) + O2(g)
June 2024, Chemistry Paper 2 Higher, Q1(a) (2 marks): Figure 1 shows part of the apparatus used in the experiment. Complete Figure 1 by drawing and labelling apparatus that could be used to collect and measure the
June 2024, Chemistry Paper 2 Higher, Q1(b)(i) (1 mark): State the total volume of carbon dioxide produced in the first 3.5 minutes. (1) volume = cm3
June 2024, Chemistry Paper 2 Higher, Q1(b)(ii) (3 marks): Using the tangent, calculate the rate of reaction at 3.5 minutes in cm3 per minute. rate of reaction = change in gas volume change in time (3) rate = cm3 per mi
June 2024, Chemistry Paper 2 Higher, Q1(c) (2 marks): The student repeats the experiment using the same mass of smaller marble chips. All other conditions remain the same. Explain the effect on the rate of reaction
June 2024, Chemistry Paper 2 Higher, Q1(d) (1 mark): Which change would make the rate of reaction slower? (1) A using the same acid at a higher temperature B using acid of a lower concentration C using a larger fl
June 2024, Chemistry Paper 2 Foundation, Q5(a) (2 marks): Figure 8 shows part of the apparatus used in the experiment. Complete Figure 8 by drawing and labelling apparatus that could be used to collect and measure the
June 2024, Chemistry Paper 2 Foundation, Q5(b)(i) (1 mark): State the total volume of carbon dioxide produced in the first 3.5 minutes. (1) volume = cm3
June 2024, Chemistry Paper 2 Foundation, Q5(b)(ii) (3 marks): Using the tangent, calculate the rate of reaction at 3.5 minutes in cm3 per minute. rate of reaction = change in gas volume change in time (3) rate = cm3 per mi
June 2024, Chemistry Paper 2 Foundation, Q5(c) (2 marks): The student repeats the experiment using the same mass of smaller marble chips. All other conditions remain the same. Explain the effect on the rate of reaction
June 2024, Chemistry Paper 2 Foundation, Q5(d) (1 mark): Which change would make the rate of reaction slower? (1) A using the same acid at a higher temperature B using acid of a lower concentration C using a larger fl
June 2024, Chemistry Paper 2 Foundation, Q5(e) (1 mark): In this experiment the volume of carbon dioxide gas produced is measured. Give a different way that the amount of carbon dioxide produced can be measured. (1)
June 2024, Chemistry Paper 2 Foundation, Q5(f) (1 mark): In this experiment there is an excess of dilute hydrochloric acid. State what you would see in the conical flask at the end of the experiment. (1)
June 2023, Chemistry Paper 2 Higher, Q1(a) (3 marks): On the grid, plot the results shown in Figure 2. Draw a curve of best fit. (3) volume of 100 gas in cm3 90 80 70 60 50 40 30 20 10 0 0 1 2 3 4 5 6 time in minut
June 2023, Chemistry Paper 2 Higher, Q1(b)(i) (1 mark): Calculate the rate of reaction for the time interval 2 to 3 minutes. (1) rate of reaction = cm3 min–1
June 2023, Chemistry Paper 2 Higher, Q1(b)(ii) (3 marks): State and explain what happens to the rate of reaction as the acid reacts with the marble chips in this experiment. (3)
June 2023, Chemistry Paper 2 Higher, Q1(c) (2 marks): The student repeated the experiment using the same volume of acid and the same mass of marble chips but used smaller marble chips. All other conditions remained
June 2023, Chemistry Paper 2 Foundation, Q5(a) (3 marks): On the grid, plot the results shown in Figure 11. Draw a curve of best fit. (3) 100 volume of gas in cm3 90 80 70 60 50 40 30 20 10 0 0 1 2 3 4 5 6 time in minu
June 2023, Chemistry Paper 2 Foundation, Q5(b)(i) (1 mark): Calculate the rate of reaction for the time interval 2 to 3 minutes. (1) rate of reaction = cm3 min–1
June 2023, Chemistry Paper 2 Foundation, Q5(b)(ii) (3 marks): State and explain what happens to the rate of reaction as the acid reacts with the marble chips in this experiment. (3)
June 2023, Chemistry Paper 2 Foundation, Q5(c) (2 marks): The student repeated the experiment using the same volume of acid and the same mass of marble chips but used smaller marble chips. All other conditions remained
June 2023, Chemistry Paper 2 Foundation, Q5(d) (1 mark): Which of the following changes would make the reaction faster? (1) A use a larger boiling tube B use a larger volume of the dilute acid C use a more concentrate
June 2023, Chemistry Paper 2 Foundation, Q5(e) (1 mark): State what could be used to measure time in the investigation. (1)
June 2022, Chemistry Paper 2 Higher, Q1(a)(i) (2 marks): Name a piece of apparatus that would be better to measure the volume of gas produced, instead of the 250 cm3 measuring cylinder. Give a reason for your answer.
June 2022, Chemistry Paper 2 Higher, Q1(a)(ii) (3 marks): Calculate the mean rate of production of hydrogen over the first 90 seconds, in cm3 per second. (3) rate = cm3 per second
June 2022, Chemistry Paper 2 Higher, Q1(a)(iii) (1 mark): The student measured the volume of gas for 10 minutes. State why the measurements could have been stopped at 9 minutes. (1)
June 2022, Chemistry Paper 2 Higher, Q1(b)(i) (2 marks): Explain why the rate of reaction increases when the concentration of acid is increased. (2)
June 2022, Chemistry Paper 2 Higher, Q1(b)(ii) (1 mark): Another student suggests four other ways of increasing the rate of this reaction. Which one is correct? (1) A use the same acid but at a lower temperature B use
June 2022, Chemistry Paper 2 Higher, Q6(b) (6 marks): The reaction profile for an uncatalysed exothermic reaction is shown in Figure 8. energy reactants products progress of reaction Figure 8 Using some examples of
June 2022, Chemistry Paper 2 Foundation, Q4(c) (2 marks): Alkenes react with halogens. When iron chloride is added to the reaction mixture, the reaction is much faster but the products are the same. Use words from the
June 2022, Chemistry Paper 2 Foundation, Q5(a)(i) (2 marks): Name a piece of apparatus that would be better to measure the volume of gas produced, instead of the 250 cm3 measuring cylinder. Give a reason for your answer.
June 2022, Chemistry Paper 2 Foundation, Q5(a)(ii) (3 marks): Calculate the mean rate of production of hydrogen over the first 90 seconds, in cm3 per second. (3) rate = cm3 per second
June 2022, Chemistry Paper 2 Foundation, Q5(a)(iii) (1 mark): The student measured the volume of gas for 10 minutes. State why the measurements could have been stopped at 9 minutes. (1)
June 2022, Chemistry Paper 2 Foundation, Q5(b)(i) (2 marks): Explain why the rate of reaction increases when the concentration of acid is increased. (2)
June 2022, Chemistry Paper 2 Foundation, Q5(b)(ii) (1 mark): Another student suggests four other ways of increasing the rate of this reaction. Which one is correct? (1) A use the same acid but at a lower temperature B use
June 2022, Chemistry Paper 2 Foundation, Q5(c) (2 marks): The apparatus in Figure 7 can be used to measure the rate of the reaction between marble chips and hydrochloric acid. The student needs different sized marble c
November 2021, Chemistry Paper 2 Higher, Q4(b) (2 marks): Some pieces of calcium carbonate were added to dilute hydrochloric acid in a conical flask and the volume of carbon dioxide produced was measured. Complete the
November 2021, Chemistry Paper 2 Higher, Q4(c)(i) (1 mark): State what could be used to keep the temperature of the conical flask and its contents at a temperature of 45 °C throughout the reaction. (1)
November 2021, Chemistry Paper 2 Higher, Q4(c)(ii) (2 marks): Figure 6 shows a graph of volume of gas collected in this investigation. volume of 100 gas in cm3 90 80 70 60 50 40 30 20 10 0 0 50 100 150 200 250 300 time in
November 2021, Chemistry Paper 2 Higher, Q4(c)(iii) (1 mark): The temperature of the acid was kept at 45 °C. State one other variable that needs to be controlled during this investigation. (1)
November 2021, Chemistry Paper 2 Higher, Q4(c)(iv) (3 marks): Explain, in terms of particles, how decreasing the temperature affects the rate of this reaction. (3)
November 2021, Chemistry Paper 2 Foundation, Q1(a) (2 marks): The student kept the volume of sulfuric acid the same when they repeated the method at 50 °C. State two other variables that should be kept the same. (2) 1 2
November 2021, Chemistry Paper 2 Foundation, Q1(b) (1 mark): Which piece of equipment can be used to find the volume of 25 cm3 of sulfuric acid? (1) A balance B measuring cylinder C ruler D thermometer
November 2021, Chemistry Paper 2 Foundation, Q1(c) (1 mark): State how the student will know that the reaction has finished. (1)
November 2021, Chemistry Paper 2 Foundation, Q1(d) (1 mark): The reaction at 50 °C was faster than the reaction at 30 °C. Give one reason, in terms of particles, why the reaction at 50 °C was faster than the reaction at 3
November 2021, Chemistry Paper 2 Foundation, Q1(e) (2 marks): At 50 °C, 15.0 cm3 of gas was produced during the first 60 seconds of the reaction. Calculate the average rate of reaction, in cm3 s–1, for the first 60 seconds
November 2021, Chemistry Paper 2 Foundation, Q4(a)(i) (1 mark): Write the word equation for hydrogen peroxide solution decomposing. (1) →
November 2021, Chemistry Paper 2 Foundation, Q4(a)(ii) (2 marks): In this reaction hydrogen peroxide is a solution, water is a liquid and oxygen is a gas. Draw one straight line from each substance to its correct state symbol.
November 2021, Chemistry Paper 2 Foundation, Q4(b) (2 marks): Describe the test to show the gas produced is oxygen. (2)
November 2021, Chemistry Paper 2 Foundation, Q4(d)(i) (1 mark): Complete the missing label on the axis of the graph. (1)
November 2021, Chemistry Paper 2 Foundation, Q4(d)(ii) (2 marks): Describe what the graph shows about the difference in decomposition of hydrogen peroxide with and without liver. (2)
November 2021, Chemistry Paper 2 Foundation, Q4(d)(iii) (2 marks): Describe how the apparatus in Figure 8 could be modified to find the volume of gas produced when the liver is added to the hydrogen peroxide. (2)
November 2020, Chemistry Paper 2 Higher, Q2(a) (1 mark): The investigation was carried out with different sized calcium carbonate pieces. The mass of calcium carbonate and all other conditions were kept the same. The
November 2020, Chemistry Paper 2 Higher, Q2(b) (3 marks): The calcium carbonate powder produced 90 cm3 of carbon dioxide in five minutes. Calculate the average rate of reaction in cm3 s–1. (3) average rate of reaction
November 2020, Chemistry Paper 2 Higher, Q2(c) (3 marks): The experiments were repeated at a higher temperature. The rate of reaction for each experiment increased. Explain, in terms of particles, why the rate of react
November 2020, Chemistry Paper 2 Higher, Q3(a)(i) (2 marks): When dilute hydrochloric acid is mixed with sodium thiosulfate solution, the mixture turns cloudy. Explain why the mixture turns cloudy. (2)
November 2020, Chemistry Paper 2 Higher, Q3(a)(ii) (3 marks): In an investigation, different concentrations of hydrochloric acid are reacted with sodium thiosulfate solution. The mixture goes cloudy at different rates. Des
November 2020, Chemistry Paper 2 Foundation, Q6(a)(i) (1 mark): The investigation was carried out with different sized calcium carbonate pieces. The mass of calcium carbonate and all other conditions were kept the same. The
November 2020, Chemistry Paper 2 Foundation, Q6(a)(ii) (3 marks): The calcium carbonate powder produced 90 cm3 of carbon dioxide in five minutes. Calculate the average rate of reaction in cm3 s–1. (3) average rate of reaction
November 2020, Chemistry Paper 2 Foundation, Q6(a)(iii) (3 marks): The experiments were repeated at a higher temperature. The rate of reaction for each experiment increased. Explain, in terms of particles, why the rate of react
November 2020, Chemistry Paper 2 Foundation, Q6(b) (6 marks): Zinc metal reacts with dilute hydrochloric acid to produce hydrogen gas. zinc + hydrochloric acid → zinc chloride + hydrogen A student investigated the effect o
June 2019, Chemistry Paper 2 Higher, Q5(a) (2 marks): A student wanted to measure the amount of gas produced in two minutes. The student suggested that this could be done by counting the number of bubbles formed. H
June 2019, Chemistry Paper 2 Higher, Q5(c) (6 marks): An investigation was carried out into the rate of reaction of calcium carbonate with dilute hydrochloric acid. 5.0g of small lumps of calcium carbonate were rea
June 2019, Chemistry Paper 2 Foundation, Q4(a) (1 mark): Name the apparatus that could be used to measure out 100 cm3 of dilute hydrochloric acid. (1)
June 2019, Chemistry Paper 2 Foundation, Q4(c) (3 marks): The graph shows that the rate of reaction slows as the reaction takes place. Explain, in terms of particles, why the rate of reaction between magnesium ribbon a
June 2019, Chemistry Paper 2 Foundation, Q4(d) (1 mark): The experiment was repeated using the acid at a higher temperature. All other conditions were kept the same. State the effect of the higher temperature on the m
June 2019, Chemistry Paper 2 Foundation, Q4(e) (2 marks): The original experiment was repeated using the same mass of magnesium powder instead of the magnesium ribbon. All other conditions were kept the same. Sketch, o
June 2019, Chemistry Paper 2 Foundation, Q4(f)(i) (1 mark): State the effect of a catalyst on a reaction. (1)
June 2019, Chemistry Paper 2 Foundation, Q4(f)(ii) (3 marks): Devise a simple experiment to find out what happens to the mass of a solid catalyst during a reaction. (3)
June 2018, Chemistry Paper 2 Higher, Q6(a)(i) (1 mark): State a change that can be made to the apparatus in Figure 6 to measure the volumes of gas more accurately. (1)
June 2018, Chemistry Paper 2 Higher, Q6(a)(ii) (2 marks): A tangent has been drawn to the line on the graph in Figure 7. Calculate the rate of reaction at this point. (2) rate of reaction = cm3 s−1
June 2018, Chemistry Paper 2 Higher, Q6(a)(iii) (1 mark): On the graph in Figure 7, draw the line you would expect to obtain if the magnesium ribbon in this experiment was replaced with an equal mass of powdered magnes
June 2018, Chemistry Paper 2 Higher, Q6(c) (6 marks): Two substances, A and B, each form a colourless solution. If the solutions are mixed in a beaker, A and B react to form a coloured product. The rate of the reac
June 2018, Chemistry Paper 2 Foundation, Q2(a) (1 mark): State the name of the piece of apparatus labelled Z in Figure 3. (1)
June 2018, Chemistry Paper 2 Foundation, Q2(b) (1 mark): At the end of the reaction the bung is removed from the conical flask. A glowing splint is put into the gas in the flask. State what you would see. (1)
June 2018, Chemistry Paper 2 Foundation, Q2(c)(i) (1 mark): The experiment is repeated under identical conditions but with the catalyst added. (1) In the experiment with the catalyst added A the rate of reaction is the s
June 2018, Chemistry Paper 2 Foundation, Q2(c)(ii) (1 mark): At the end of the experiment with the catalyst added, the mass of the catalyst remaining is found. The method used to find the mass of the catalyst remaining is
June 2018, Chemistry Paper 2 Foundation, Q2(c)(iii) (1 mark): A given mass of catalyst is more effective if it has a large surface area. State how you could increase the surface area of some lumps of solid catalyst. (1)
June 2018, Chemistry Paper 2 Foundation, Q2(d) (2 marks): The experiment is repeated three times once using a more dilute solution of hydrogen peroxide once using a lower temperature once using a larger flask In each c
June 2018, Chemistry Paper 2 Foundation, Q2(e) (2 marks): Complete the balanced equation for the reaction and fill in the two missing state symbols. (2) H2O2(aq) o 2H2O( ) + O2( )

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