How do chemists control the rate of reactions?: OCR GCSE Chemistry B questions

Every OCR GCSE Chemistry B exam question on C6.2 How do chemists control the rate of reactions?, 2018–2025, with its mark scheme and examiner’s report.

All 119 questions on How do chemists control the rate of reactions?, as a list

June 2025, Paper 1 Foundation, Q9(a) (3 marks): The student does three experiments adding limestone to dilute hydrochloric acid. In all three experiments, the student keeps these the same: • the mass of limes
June 2025, Paper 1 Foundation, Q9(b)(i) (2 marks): Draw a line on Fig. 9.1 to show the expected results for experiment 2. Use the information in Table 9.1 to help you. [2]
June 2025, Paper 1 Foundation, Q9(b)(ii) (2 marks): Experiment 3 is the fastest. Explain why. Use the information in Table 9.1. Include ideas about collisions in your answer. [2]
June 2025, Paper 1 Foundation, Q9(c)(i) (2 marks): Which metal A, B, C or D is the best metal to use as a catalyst in this reaction? Explain your reasoning. Use the information in Table 9.2. Metal Explanation [2
June 2025, Paper 1 Foundation, Q9(c)(ii) (2 marks): Which statements about catalysts are true and which are false? Tick (✓) one box in each row. True False A catalyst changes the overall energy change for a react
June 2025, Paper 3 Higher, Q1(a) (3 marks): The student does three experiments adding limestone to dilute hydrochloric acid. In all three experiments, the student keeps these the same: • the mass of limes
June 2025, Paper 3 Higher, Q1(b)(i) (2 marks): Draw a line on Fig. 1.1 to show the expected results for experiment 2. Use the information in Table 1.1 to help you. [2]
June 2025, Paper 3 Higher, Q1(b)(ii) (2 marks): Experiment 3 is the fastest. Explain why. Use the information in Table 1.1. Include ideas about collisions in your answer. [2]
June 2025, Paper 3 Higher, Q1(c)(i) (2 marks): Which metal A, B, C or D is the best metal to use as a catalyst in this reaction? Explain your reasoning. Use the information in Table 1.2. Metal Explanation [2
June 2025, Paper 3 Higher, Q1(c)(ii) (2 marks): Which statements about catalysts are true and which are false? Tick (✓) one box in each row. True False A catalyst changes the overall energy change for a react
June 2025, Paper 3 Higher, Q10(c) (2 marks): A student measures the reaction time when magnesium reacts with two different acids, dilute hydrochloric acid and a dilute weak acid. The student keeps the same
June 2025, Paper 4 Higher, Q8(b) (3 marks): Fig. 8.1 shows a reaction profile diagram for a catalysed and an uncatalysed reaction. Fig. 8.1 Energy Reactants Products Progress of reaction Complete Fig. 8.1
June 2024, Paper 1 Foundation, Q5(a)(iii) (1 mark): The reaction needs a catalyst to form the product. Which of these is a property of a catalyst? Tick (✓) one box. It is used up during the reaction. It lowers th
June 2024, Paper 2 Foundation, Q11(a)(i) (3 marks): Complete the diagram to show how the student sets up their measuring cylinder to collect the gas over water. Include labels on your diagram. Dilute acid Solid [
June 2024, Paper 2 Foundation, Q11(a)(ii) (1 mark): The student finds it difficult to measure the volume accurately in the measuring cylinder. Suggest another method they could use to get more accurate readings.
June 2024, Paper 2 Foundation, Q11(b)(i) (3 marks): Calculate the gradient of the tangent shown on the graph. Gradient = cm3 / s [3]
June 2024, Paper 2 Foundation, Q11(b)(ii) (1 mark): What information does your answer to (i) give about the reaction? Tick (3) one box. The increase in volume and time at 180 s. The rate of reaction at 120 s. The
June 2024, Paper 2 Foundation, Q11(c) (2 marks): The student repeats their experiment using different conditions. The rate of the reaction increases each time. Draw lines to connect each change in condition wi
June 2024, Paper 3 Higher, Q7(a) (1 mark): Manganese dioxide is a catalyst for this reaction. Which statement explains how manganese dioxide speeds up the reaction? Tick (✓) one box. It decreases the fre
June 2024, Paper 3 Higher, Q7(b) (2 marks): Explain why increasing the concentration of the aqueous hydrogen peroxide also speeds up the reaction. Use ideas about particles. [2]
June 2024, Paper 4 Higher, Q2(a)(i) (3 marks): Complete the diagram to show how the student sets up their measuring cylinder to collect the gas over water. Include labels on your diagram. Dilute acid Solid [
June 2024, Paper 4 Higher, Q2(a)(ii) (1 mark): The student finds it difficult to measure the volume accurately in the measuring cylinder. Suggest another method they could use to get more accurate readings.
June 2024, Paper 4 Higher, Q2(b)(i) (3 marks): Calculate the gradient of the tangent shown on the graph. Gradient = cm3 / s [3]
June 2024, Paper 4 Higher, Q2(b)(ii) (1 mark): What information does your answer to (i) give about the reaction? Tick (3) one box. The increase in volume and time at 180 s. The rate of reaction at 120 s. The
June 2024, Paper 4 Higher, Q2(c) (2 marks): The student repeats their experiment using different conditions. The rate of the reaction increases each time. Draw lines to connect each change in condition wi
June 2023, Paper 2 Foundation, Q7(a) (2 marks): Complete the diagram by drawing and labelling the apparatus she needs to collect and measure 10 cm3 gas. Zinc and dilute acid [2]
June 2023, Paper 2 Foundation, Q7(b)(i) (2 marks): What conclusion can you make about the effect of changing the temperature on the rate of the reaction? Explain your answer. [2]
June 2023, Paper 2 Foundation, Q7(b)(ii) (1 mark): Suggest why no gas is collected when copper is used in the experiment. [1]
June 2023, Paper 2 Foundation, Q7(b)(iii) (2 marks): Suggest the name of metal X. Explain your answer. Name Explanation [2]
June 2023, Paper 2 Foundation, Q7(c) (6 marks): Eve does an experiment to find out the rate of reaction when solid zinc reacts with dilute acid. She adds the zinc to the dilute acid and measures the time take
June 2023, Paper 4 Higher, Q4(a)(iii) (2 marks): Platinum acts as a catalyst for the reaction between hydrogen and oxygen. Explain the effect of a catalyst on the reaction between hydrogen and oxygen. Use idea
June 2022, Paper 1 Foundation, Q7(b)(i) (1 mark): Jack looks at his results from Experiment 1 and Experiment 2. How do the results of these two experiments show that the powder reacts faster than the lumps? [1]
June 2022, Paper 1 Foundation, Q7(b)(ii) (2 marks): Explain why the powder reacts faster than the lumps. Use ideas about particles in your answer. [2]
June 2022, Paper 1 Foundation, Q7(c) (1 mark): What is the most likely time taken for Experiment 3? Tick (✓) one box. Less than 6 minutes. 6 minutes. Between 6 and 10 minutes. 10 minutes. Longer than 10 minu
June 2022, Paper 1 Foundation, Q11(b)(i) (3 marks): Calculate the rate of reaction during the first minute, using Fig. 11.2. Give your answer in cm3 / s. Rate of reaction = cm3 / s [3]
June 2022, Paper 1 Foundation, Q11(c) (3 marks): Mia repeats the experiment at the same temperature. She adds a few drops of blue copper sulfate. Her results show that: • more gas is produced in the first minu
June 2022, Paper 1 Foundation, Q11(d) (2 marks): Mia repeats the experiment at a higher temperature. Which statements explain why the reaction is faster at a higher temperature? Tick (✓) two boxes. The particl
June 2022, Paper 3 Higher, Q1(b)(i) (3 marks): Calculate the rate of reaction during the first minute, using Fig. 1.2. Give your answer in cm3 / s. Rate of reaction = cm3 / s [3]
June 2022, Paper 3 Higher, Q1(c) (3 marks): Mia repeats the experiment at the same temperature. She adds a few drops of blue copper sulfate. Her results show that: • more gas is produced in the first minu
June 2022, Paper 3 Higher, Q1(d) (2 marks): Mia repeats the experiment at a higher temperature. Which statements explain why the reaction is faster at a higher temperature? Tick (✓) two boxes. The particl
June 2022, Paper 3 Higher, Q9(b)(i) (2 marks): Explain why the rates of Experiment 1 and Experiment 2 are different in Table 9.1. Use ideas about particles in your answer. [2]
June 2022, Paper 3 Higher, Q9(b)(ii) (2 marks): Relative average rate is the number of times faster one reaction is compared to another. Calculate the relative average rate of Experiment 2, compared to Experi
June 2022, Paper 3 Higher, Q9(c) (2 marks): Alex does two more experiments, Experiment 3 and Experiment 4. The results are shown in Table 9.2. Mass of zinc Concentration Time to Relative Type of zinc Expe
November 2021, Paper 1 Foundation, Q9(a)(i) (1 mark): What is the gradient of the curve at 5 minutes? Gradient = cm3 / minute [1]
November 2021, Paper 1 Foundation, Q9(a)(ii) (1 mark): What happens to the reaction after 5 minutes? [1]
November 2021, Paper 1 Foundation, Q9(b) (1 mark): Which value is a correct estimate for the rate at which the reaction starts? Use Fig. 9.2. Tick (3) one box. 0.08 cm3 / minute 0.1 cm3 / minute 10 cm3 / minute
November 2021, Paper 1 Foundation, Q9(d) (2 marks): Alex repeats the experiment with different metals and excess acid. He wants to compare the rate of reaction for the different metals. State two factors that he
November 2021, Paper 1 Foundation, Q9(e) (2 marks): Fig. 9.3 shows Alex’s results for zinc, magnesium and iron: Volume of gas (cm3) A B C Time (minutes) Fig. 9.3 Which metal makes each curve in Fig. 9.3? Curve A
November 2021, Paper 2 Foundation, Q6(a) (1 mark): All of the acids in the table react with magnesium metal. Which acid gives the fastest reaction? Tick (✓) one box. 0.1 mol / dm3 hydrochloric acid 0.01 mol / dm
November 2021, Paper 2 Foundation, Q9(a)(i) (1 mark): How long does it take for the reaction to finish? minutes [1]
November 2021, Paper 2 Foundation, Q9(a)(ii) (1 mark): How much oxygen is given off by the end of the reaction? cm3 [1]
November 2021, Paper 2 Foundation, Q9(a)(iii) (2 marks): Calculate the average volume of oxygen given off per second. cm3 / s [2]
November 2021, Paper 2 Foundation, Q9(b) (2 marks): The reaction that breaks down hydrogen peroxide does not start until the enzyme is added. When the enzyme is added, oxygen is given off quickly. Explain this st
November 2021, Paper 3 Higher, Q2(a)(i) (1 mark): What is the gradient of the curve at 5 minutes? Gradient = cm3 / minute [1]
November 2021, Paper 3 Higher, Q2(a)(ii) (1 mark): What happens to the reaction after 5 minutes? [1]
November 2021, Paper 3 Higher, Q2(b) (1 mark): Which value is a correct estimate for the rate at which the reaction starts? Use Fig. 2.2. Tick (✓) one box. 0.08 cm3 / minute 0.1 cm3 / minute 10 cm3 / minute
November 2021, Paper 3 Higher, Q2(d) (2 marks): Alex repeats the experiment with different metals and excess acid. He wants to compare the rate of reaction for the different metals. State two factors that he
November 2021, Paper 3 Higher, Q2(e) (2 marks): Fig. 2.3 shows Alex’s results for zinc, magnesium and iron: Volume of gas (cm3) A B C Time (minutes) Fig. 2.3 Which metal makes each curve in Fig. 2.3? Curve A
November 2021, Paper 3 Higher, Q3(c)(i) (1 mark): Suggest why a catalyst is added to the hand warmer. [1]
November 2021, Paper 3 Higher, Q3(c)(ii) (1 mark): Why does the catalyst have the effect identified in (c)(i)? Use ideas about energy in your answer. [1]
November 2021, Paper 3 Higher, Q3(d) (2 marks): The iron is in powdered form. Explain why this makes the reaction go quickly. Use ideas about particles in your answer. [2]
November 2021, Paper 4 Higher, Q2(a)(i) (1 mark): How long does it take for the reaction to finish? minutes [1]
November 2021, Paper 4 Higher, Q2(a)(ii) (1 mark): How much oxygen is given off by the end of the reaction? cm3 [1]
November 2021, Paper 4 Higher, Q2(a)(iii) (2 marks): Calculate the average volume of oxygen given off per second. cm3 / s [2]
November 2021, Paper 4 Higher, Q2(b) (2 marks): The reaction that breaks down hydrogen peroxide does not start until the enzyme is added. When the enzyme is added, oxygen is given off quickly. Explain this st
November 2020, Paper 1 Foundation, Q11(a)(i) (1 mark): When should Beth stop the stopwatch? Tick (3) one box. When the bubbles start to appear. When the fizzing starts. When the fizzing stops. When only a small amou
November 2020, Paper 1 Foundation, Q11(a)(ii) (2 marks): Which type of tablet, whole or broken-up, will dissolve more quickly? Whole tablet Broken-up tablet Explain your answer. Use ideas from the particle model in yo
November 2020, Paper 1 Foundation, Q11(b) (1 mark): Suggest one reason why the reactions are much faster using hot water. [1]
November 2020, Paper 1 Foundation, Q11(c)(i) (1 mark): Using Fig. 11.2, explain why the mass of Tube A and its contents decreases during the reaction. [1]
November 2020, Paper 1 Foundation, Q11(c)(ii) (1 mark): The rate of the reaction decreases with time. Describe how Fig. 11.2 shows this. [1]
November 2020, Paper 1 Foundation, Q11(c)(iii) (1 mark): Explain why the rate of reaction decreases with time. [1]
November 2020, Paper 2 Foundation, Q4(a) (1 mark): When dilute hydrochloric acid reacts with zinc a gas is made. This is the word and symbol equation for the reaction between zinc and dilute hydrochloric acid. z
November 2020, Paper 2 Foundation, Q4(b) (2 marks): Beth uses this apparatus to collect and measure the amount of gas that is made. Complete the diagram to show how the gas is collected. measuring cylinder zinc d
November 2020, Paper 2 Foundation, Q4(c)(i) (3 marks): What conclusions can you make about the effects of changing each variable on the rate of the reaction? Use the data in Table 4.1 to explain your reasons. Concen
November 2020, Paper 2 Foundation, Q4(c)(ii) (3 marks): What conditions did Beth use for her control experiment? Put a ring around one condition in each row. Use the data in Table 4.1 to help you. 1.0 mol / dm3 2.0 m
November 2020, Paper 2 Foundation, Q4(d) (2 marks): Beth repeats her control experiment, but now adds a small amount of catalyst to the reaction mixture. How does adding a catalyst affect the reaction? Tick (3) t
November 2020, Paper 3 Higher, Q2(a)(i) (1 mark): When should Beth stop the stopwatch? Tick (✓) one box. When the bubbles start to appear. When the fizzing starts. When the fizzing stops. When only a small amou
November 2020, Paper 3 Higher, Q2(a)(ii) (2 marks): Which type of tablet, whole or broken-up, will dissolve more quickly? Whole tablet Broken-up tablet Explain your answer. Use ideas from the particle model in yo
November 2020, Paper 3 Higher, Q2(b) (1 mark): Suggest one reason why the reactions are much faster using hot water. [1]
November 2020, Paper 3 Higher, Q2(c)(i) (1 mark): Using Fig. 2.2, explain why the mass of Tube A and its contents decreases during the reaction. [1]
November 2020, Paper 3 Higher, Q2(c)(ii) (1 mark): The rate of the reaction decreases with time. Describe how Fig. 2.2 shows this. [1]
November 2020, Paper 3 Higher, Q2(c)(iii) (1 mark): Explain why the rate of reaction decreases with time. [1]
November 2020, Paper 4 Higher, Q4(b) (2 marks): Complete the diagram to suggest how the hydrogen gas could be collected and measured. Include labels on your diagram. Dilute hydrochloric acid Zinc [2]
November 2020, Paper 4 Higher, Q4(c)(i) (2 marks): Calculate the gradient of the line. Show your working on the graph. Gradient = cm3 / mol / dm3 [2]
November 2020, Paper 4 Higher, Q4(c)(ii) (2 marks): Estimate the concentration of dilute hydrochloric acid needed to produce 250 cm3 of gas in 20 s. Use the equation: volume of gas produced in 20 s = gradient × c
November 2020, Paper 4 Higher, Q4(d)(i) (2 marks): Plot the results in Table 4.1 on Fig. 4.1. Draw a line of best fit. [2]
November 2020, Paper 4 Higher, Q4(d)(ii) (2 marks): Explain why the two lines on Fig. 4.1 have different gradients. [2]
June 2019, Paper 1 Foundation, Q8(a)(i) (2 marks): Plot a graph of mass against time on the axes below, using Table 8.1. Add a curve of best fit to the graph. [2] 300 299 298 297 296 mass (g) 295 294 293 292 291
June 2019, Paper 1 Foundation, Q8(a)(ii) (1 mark): Estimate the mass of the beaker at 100 seconds. Use the graph to help you. Mass at 100 seconds = g [1]
June 2019, Paper 1 Foundation, Q8(a)(iii) (1 mark): Draw an F on your graph where the rate of reaction is the fastest. [1]
June 2019, Paper 1 Foundation, Q8(b)(i) (1 mark): Describe the rate of change of mass during the reaction. [1]
June 2019, Paper 1 Foundation, Q8(b)(ii) (1 mark): Explain how you worked this out from the graph. [1]
June 2019, Paper 1 Foundation, Q9(c) (1 mark): Sundip then drops some zinc powder into some dilute sulfuric acid. Explain why the fizzing is faster with zinc powder. [1]
June 2019, Paper 1 Foundation, Q9(d) (2 marks): Sundip adds some blue copper sulfate solution and zinc to the acid. Sundip thinks that the copper sulfate is a catalyst in the reaction. If Sundip is right, whi
June 2019, Paper 3 Higher, Q8(a) (1 mark): Sundip drops a piece of zinc into some dilute sulfuric acid. She then drops some zinc powder into the dilute sulfuric acid. Which reaction is faster? Explain yo
June 2019, Paper 3 Higher, Q8(b) (2 marks): Sundip adds some blue copper sulfate solution to the sulfuric acid. She then drops in a piece of zinc. Sundip thinks copper sulfate is a catalyst. Describe two
June 2019, Paper 3 Higher, Q8(c)(ii) (2 marks): Sundip repeats (c)(i) with a catalyst present. How does the volume of hydrogen compare with the volume calculated in part (c)(i)? Give one reason for your answe
June 2019, Paper 3 Higher, Q12(a)(i) (1 mark): Draw a curve of best fit on the graph in Fig 12.2. [1]
June 2019, Paper 3 Higher, Q12(a)(ii) (2 marks): Use Fig. 12.2 to calculate the initial rate of reaction. Initial rate of reaction = g / s [2]
June 2019, Paper 3 Higher, Q12(a)(iii) (1 mark): Describe how the rate of reaction changes with time. [1]
June 2019, Paper 3 Higher, Q12(a)(iv) (2 marks): Use Fig. 12.2 to estimate the total mass loss in the reaction after 100 seconds has passed. Explain how you obtained your answer. Total mass loss = g [2]
June 2018, Paper 1 Foundation, Q11(b) (2 marks): Cerium oxide is a very expensive solid. The cerium oxide nanoparticles act as a catalyst. They help the fuel to burn completely so that less pollutant gases are
June 2018, Paper 1 Foundation, Q12(a) (2 marks): Use the graph to calculate the rate of reaction over the first 100 s. Rate = cm3 / s [2]
June 2018, Paper 1 Foundation, Q12(b) (2 marks): Amaya wants to repeat Jack’s experiment. She uses the same mass of calcium carbonate. She uses the same volume and concentration of hydrochloric acid. Which two
June 2018, Paper 1 Foundation, Q12(c) (2 marks): Jack repeats his experiment with more concentrated hydrochloric acid. He keeps all other factors the same. The rate of reaction is faster. Explain why. Write ab
June 2018, Paper 2 Foundation, Q7(a)(i) (1 mark): What volume of gas is given off during the first minute of the reaction? Volume = cm3 [1]
June 2018, Paper 2 Foundation, Q7(a)(ii) (2 marks): What volume of gas is given off during the second minute of the reaction? Volume = cm3 [2]
June 2018, Paper 2 Foundation, Q7(b) (2 marks): Look at the graph in Fig. 7.1. Describe what happens to the rate of the reaction during the experiment. [2]
June 2018, Paper 2 Foundation, Q7(c)(i) (2 marks): Predict the rate of reaction when acid of concentration 0.5 mol / dm3 is used. Rate of reaction = cm3 / s [2]
June 2018, Paper 2 Foundation, Q7(c)(ii) (2 marks): Eve says that the data shows that rate of reaction is proportional to the concentration. How does the data show that Eve is right? [2]
June 2018, Paper 2 Foundation, Q7(c)(iii) (1 mark): Eve writes an expression to show that rate of reaction is proportional to concentration. Which expression shows that rate of reaction is proportional to concent
June 2018, Paper 3 Higher, Q1(a) (2 marks): Use the graph to calculate the rate of reaction over the first 100 s. Rate = cm3 / s [2]
June 2018, Paper 3 Higher, Q1(b) (2 marks): Amaya wants to repeat Jack’s experiment. She uses the same mass of calcium carbonate. She uses the same volume and concentration of hydrochloric acid. Which two
June 2018, Paper 3 Higher, Q1(c) (2 marks): Jack repeats his experiment with more concentrated hydrochloric acid. He keeps all other factors the same. The rate of reaction is faster. Explain why. Write ab
June 2018, Paper 4 Higher, Q9(a)(i) (3 marks): Calculate the rate of reaction at the start by calculating the gradient of the tangent. Rate = cm3/s [3]
June 2018, Paper 4 Higher, Q9(a)(ii) (1 mark): Draw a new tangent on the graph at time = 60 s. [1]
June 2018, Paper 4 Higher, Q9(a)(iii) (2 marks): How do the tangents show that the rate of reaction has changed from the start to 60 s? [2]
June 2018, Paper 4 Higher, Q9(b)(i) (2 marks): Eve thinks that the relationship between rate and concentration in the graph in Fig. 9.2 can be shown using this equation: rate a concentration Does the graph i
June 2018, Paper 4 Higher, Q9(b)(ii) (2 marks): Using the graph in Fig. 9.2 estimate the rate of reaction when acid of concentration 3.0 mol / dm3 is used. Rate of reaction = cm3 / s [2]

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