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
141–150 of 164
Question 141
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 142
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 143
2 marks · Normal
Answer and see the solution →State two reasons why catalysts are important in industrial chemical reactions.
Question 144
4 marks · Normal
Answer and see the solution →Read the passage below and answer the questions that follow.
(a)[2 marks]Explain how a catalyst lowers the activation energy of a reaction.
(b)[1 mark]State what effect a catalyst has on the overall enthalpy change (ΔH) of the reaction.
(c)[1 mark]Does the catalyst get used up in the reaction? Explain your answer.
Question 145
3 marks · Normal
Answer and see the solution →The diagram below shows the energy changes in a reaction with and without a catalyst.
Reaction profile showing catalysed and uncatalysed paths. The activation energy for the uncatalysed reaction is 100 kJ/mol, and the activation energy for the catalysed reaction is 60 kJ/mol. The enthalpy change (ΔH) for the reaction is -40 kJ/mol.
Calculate the difference in activation energy between the catalysed and uncatalysed routes, and explain what effect this has on the rate of reaction.
Question 146
3 marks · Normal
Answer and see the solution →You are given an unknown white powder and asked to find out if it is a catalyst for the decomposition of hydrogen peroxide solution. Describe how you would show that this substance is a catalyst in the reaction.
Question 147
4 marks · Normal
Answer and see the solution →An industrial process uses iron as a catalyst for the reaction between nitrogen and hydrogen to form ammonia (the Haber process):
The data below show the percentage yield of ammonia at two different temperatures, with and without the iron catalyst.
Temperature/°C Catalyst present? Percentage yield of ammonia 400 No 15 400 Yes 15 500 No 10 500 Yes 10 Use the information in the table to answer the questions.
(a)[1 mark]Does the iron catalyst affect the percentage yield of ammonia at these temperatures? Explain your answer.
(b)[2 marks]Explain why the use of the iron catalyst is still important in this industrial process.
(c)[1 mark]Suggest one economic benefit of using a catalyst in the Haber process.
Question 148
1 mark · Normal
Answer and check →Which statement best describes how a catalyst speeds up a reaction?
- A.A catalyst increases the total enthalpy change (ΔH) of a reaction.
- B.A catalyst provides an alternative pathway with lower activation energy.
- C.A catalyst makes the products more stable.
- D.A catalyst increases the concentration of reactants.
Question 149
2 marks · Normal
Answer and see the solution →Draw a reaction profile diagram for a reaction with and without a catalyst. Clearly label the energy of reactants, energy of products, activation energy with and without catalyst, and the enthalpy change (ΔH).
Question 150
4 marks · Normal
Answer and see the solution →You want to test whether a black solid is a catalyst for the decomposition of hydrogen peroxide solution.
(a)[2 marks]Describe how you would carry out the experiment to test if the black solid is a catalyst.
(b)[2 marks]Explain how you would show that the black solid is unchanged after the reaction.