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
11–20 of 69 · Normal
Question 11
3 marks · Normal
Answer and see the solution →A student investigates the reaction between sodium thiosulfate and hydrochloric acid at two different temperatures. The reaction is much faster at 45°C than at 25°C. Explain, using collision theory, why increasing the temperature increases the rate of this reaction.
Question 12
4 marks · Normal
Answer and see the solution →The graph below shows the concentration of hydrochloric acid over time during its reaction with excess calcium carbonate.
Concentration of hydrochloric acid vs time (a)[2 marks]Describe how the rate of reaction changes during the experiment.
(b)[2 marks]Explain the shape of the curve using collision theory.
Question 13
1 mark · Normal
Answer and check →Which statement best explains why a reaction only occurs when particles collide with at least the activation energy?
- A.It allows more particles to react with each other at low temperatures.
- B.It provides enough energy to break existing bonds for the reaction to occur.
- C.It increases the frequency of collisions between reactant particles.
- D.It makes the product more stable after the reaction.
Question 14
2 marks · Normal
Answer and see the solution →State the two conditions that must be met for a collision between reactant particles to lead to a reaction, according to collision theory.
Question 15
4 marks · Normal
Answer and see the solution →A reaction between excess zinc and dilute sulfuric acid is carried out in a conical flask. The total volume of hydrogen gas produced is measured.
(a)[1 mark]State one way the rate of this reaction could be increased without changing the temperature.
(b)[3 marks]Explain your answer to part (a) using collision theory.
Question 16
3 marks · Normal
Answer and see the solution →A student reacts marble chips (calcium carbonate) with dilute hydrochloric acid in a beaker. At the start, there are 60 acid particles per cm³ in the solution. Every second, about 18 of these particles collide with the marble chips. Only 5 of these collisions have enough energy to result in a reaction and are called successful collisions.
(a)[2 marks]Calculate the percentage of collisions that are successful each second at the start of the reaction.
(b)[1 mark]Explain, using collision theory, what happens to the rate of reaction as the number of acid particles falls during the experiment.
Question 17
2 marks · Normal
Answer and see the solution →A student reacts powdered calcium carbonate with dilute hydrochloric acid. Explain why the reaction happens faster than if the same mass of calcium carbonate is in large lumps, not powder.
Question 18
4 marks · Normal
Answer and see the solution →Solid magnesium ribbon reacts with dilute sulfuric acid to produce hydrogen gas. A student wants to investigate how changing the surface area of magnesium affects the rate of reaction.
(a)[1 mark]Describe a change the student could make to increase the surface area of magnesium used.
(b)[2 marks]Explain how this change affects the rate of the reaction.
(c)[1 mark]State one variable other than surface area that should be kept constant in this investigation.
Question 19
3 marks · Normal
Answer and see the solution →A student conducts two experiments: - Experiment 1: 5.0 g of marble chips (large lumps) - Experiment 2: 5.0 g marble powder Both react with identical volumes and concentrations of dilute hydrochloric acid at the same temperature. In Experiment 1, all the marble has reacted in 7 minutes. In Experiment 2, the reaction is complete in 2 minutes.
Calculate the average rate of reaction in grams of marble reacted per minute for: (a) Experiment 1 (b) Experiment 2.
Question 20
3 marks · Normal
Answer and see the solution →A factory grinds solid reactants used in a chemical process into fine powder instead of using large lumps. Explain, with reasons, how and why this affects the rate of the reaction.