Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Rates of Reaction
164 practice questions
Topics covered
- Experiments to measure the rate of reaction19 practice questions
- Explaining what's happening19 practice questions
- Changing the surface area of the reactants19 practice questions
- Changing the concentration of the reactants19 practice questions
- Changing the pressure on the reaction19 practice questions
- What are catalysts?19 practice questions
- How does a catalyst work?20 practice questions
- Catalysts in industry19 practice questions
Practice questions
61–68 of 68 · Easy
Question 61
1 mark · Easy
Answer and see the solution →State how a catalyst affects the activation energy of a reaction.
Question 62
3 marks · Easy
Answer and see the solution →(a)[3 marks]Draw a fully labelled reaction profile diagram for a reaction that is exothermic, showing the effect of a catalyst.
Question 63
2 marks · Easy
Answer and see the solution →In an experiment, two reactions are compared: one with a catalyst and one without. The time for the reaction without a catalyst is 30 minutes. With a catalyst, the same reaction takes 10 minutes. If a student wants to show the substance is a catalyst, what further step should she take besides measuring the rates? Explain your answer.
Question 64
2 marks · Easy
Answer and see the solution →Draw a reaction profile diagram for a reaction. Your diagram should show both the activation energy for the uncatalysed and catalysed reaction paths. Clearly label the energy of reactants, energy of products, activation energy for both paths, and the effect of the catalyst.
Question 65
5 marks · Easy
Answer and see the solution →Some students investigate how quickly a metal carbonate reacts with dilute acid. They want to investigate the effect of changing the surface area of the solid on the rate of reaction.
(a)[2 marks]Describe how the students could carry out an experiment to investigate the effect of surface area on the rate of reaction between calcium carbonate and dilute hydrochloric acid.
(b)[1 mark]State one way the results from this experiment could be measured.
(c)[2 marks]Explain, using collision theory, why smaller pieces of calcium carbonate react faster than large pieces when added to hydrochloric acid.
Question 66
5 marks · Easy
Answer and see the solution →The diagram below shows apparatus used to measure the rate of a reaction between marble chips (calcium carbonate) and dilute hydrochloric acid.
Apparatus for measuring mass loss. (a)[1 mark]State what happens to the mass reading as the reaction occurs.
(b)[1 mark]Suggest why a cotton wool plug is placed in the neck of the flask.
(c)[2 marks]Describe two different ways to increase the rate of this reaction.
(d)[1 mark]Explain, using collision theory, why increasing the temperature increases the rate of reaction.
Question 67
5 marks · Easy
Answer and see the solution →A student carries out an experiment to measure how quickly hydrogen peroxide decomposes using a catalyst. The volume of oxygen gas collected every 30 seconds is shown on a graph: the curve is steep at first, then becomes less steep and finally flat.
(a)[1 mark]State one piece of apparatus the student could use to collect the oxygen gas.
(b)[1 mark]Describe how using a different catalyst could help the student measure the effect of catalysts on the rate.
(c)[1 mark]State what happens to the rate of reaction as shown by the graph.
(d)[2 marks]Explain why the rate of reaction changes in this way, using ideas from collision theory.
Question 68
5 marks · Easy
Answer and see the solution →A student investigates the rate of reaction between excess marble chips (calcium carbonate) and dilute hydrochloric acid in a flask. The CO produced escapes, causing the total mass to decrease. The student records the following results:
Data for the reaction Time (min) Mass lost (g) 0 0.00 1 0.52 2 0.81 3 0.95 (a)[2 marks]Calculate the average rate of reaction in g/min during the first 2 minutes. Show your working.
(b)[3 marks]Use collision theory to explain why the rate of reaction changes after the first 2 minutes. Refer to the results from part (a) in your answer.