The newest 19 of 18 written questions. Open one to see it on the real paper.
In all three reactions, 96 cm? of carbon dioxide gas is collected. Calculate the rate at which carbon dioxide gas is collected in the reaction that finished at 50s.
See it on the paper →Describe the effect, if any, on the time taken for the reactions to finish if the concentration of the hydrochloric acid is increased.
See it on the paper →The reaction between calcium carbonate and dilute hydrochloric acid is faster if the concentration of the acid used is greater. Explain why, using collision theory.
See it on the paper →The student measures the total volume of gas made every minute. The student does the experiment using manganese( IV ) oxide powder. The student repeats the experiment using manganese( IV ) oxide lumps. Fig. 7.1 shows a graph of the student’s results. 60 A 50 B total 40 volume of gas 30 / cm 3 20 10 0 0 1 2 3 4 5 6 7 8...
See it on the paper →The mass of the conical flask and contents decreases during the experiment. Explain why the mass decreases.
See it on the paper →State two changes to the reaction conditions that will increase the rate of reaction.
See it on the paper →State two changes to the reaction conditions that will increase the rate of reaction.
See it on the paper →It was common for candidates to suggest evaporation or dissolving as the cause of the loss in mass. Others gave vague answers about the reactants being used up. It was also common for candidates to suggest that the hydrochloric acid was turning to gas (implying evaporation) or being boiled which was not credited.
— Examiner report, May/June 2025, 0654/32 Q8(b)(ii) (Cambridge)
Candidates were not consistent in saying what the change would be. In many cases they identified a variable that they could change, for example temperature, but did not then go on to explain that they would increase the temperature. Candidates particularly struggled to explain how they would change the calcium carbonate to increase the rate of reaction. Many suggested more pieces rather than using...
— Examiner report, May/June 2025, 0654/32 Q8(b)(iv) (Cambridge)
Candidates were not consistent in saying what the change would be. In many cases they identified a variable that they could change, for example temperature, but did not then go on to explain that they would increase the temperature. Candidates particularly struggled to explain how they would change the calcium carbonate to increase the rate of reaction. Many suggested more pieces rather than using...
— Examiner report, May/June 2025, 0654/33 Q8(b)(iv) (Cambridge)
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Which change increases the rate of the reaction?
See it on the paper →State which marble chips, A, B or C, are the smallest.
See it on the paper →Look at the line for marble chips B. State when the rate of reaction is the greatest. 0 – 30 s 30 – 60 s 60 – 90 s 90 – 120 s Choose your answer from the list. ,
See it on the paper →State two changes to the reaction conditions that increase the rate of reaction.
See it on the paper →Suggest why the calcium carbonate is broken into small pieces before being thermally decomposed.
See it on the paper →When calcium carbonate and dilute hydrochloric acid react, the rate of reaction is slow. Suggest two ways of increasing the rate of reaction.
See it on the paper →State which reaction took the longest to finish. Choose from experiments 1, 2 or 3.
See it on the paper →The student uses 1 g of zinc in experiment 1. Suggest the mass of zinc used in experiment 3. mass of zinc = g
See it on the paper →The student wants to increase the rate of the decomposition of the hydrogen peroxide solution. He does not want to change the catalyst or the volume of the hydrogen peroxide solution. Describe and explain one way that the student can use to increase the rate of the reaction. Explain your answer in terms of collisions b...
See it on the paper →Suggest two ways of increasing the rate of reaction between magnesium and dilute sulfuric acid.
See it on the paper →Rainwater is slightly acidic. The acid in rainwater reacts very slowly with limestone rocks. Suggest two reasons for the very slow rate of reaction between rainwater and limestone rocks.
See it on the paper →State one change to the reaction conditions that reduces the rate of reaction.
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