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 27 · Hard
Question 11
5 marks · Hard
Answer and see the solution →A student prepares dilute hydrochloric acid for a reaction by adding water to a known volume of 2.50 mol/dm³ hydrochloric acid. She then uses the solution to react with marble chips.
(a)[2 marks]She mixes 10.0 cm³ of 2.50 mol/dm³ acid with 30.0 cm³ of water to make 40.0 cm³ of solution. Calculate the concentration, in mol/dm³, of the hydrochloric acid after dilution.
(b)[2 marks]She repeats the process, using 25.0 cm³ of 2.50 mol/dm³ acid topped up with water to 40.0 cm³. Calculate the new concentration, in mol/dm³, after dilution.
(c)[1 mark]State the formula used to calculate the final concentration when diluting a solution.
Question 12
2 marks · Hard
Answer and see the solution →An experiment produced 0.46 g of carbon dioxide in the first 20 seconds during the reaction of marble chips with dilute hydrochloric acid. Calculate the average rate of carbon dioxide production, giving your answer in g/s. Show your working.
Question 13
2 marks · Hard
Answer and see the solution →A chemical reaction between nitrogen and hydrogen gases is taking place in a sealed vessel. The pressure inside the vessel is increased while the temperature remains constant.
Describe and explain what happens to the rate of reaction when the pressure is increased.
Question 14
5 marks · Hard
Answer and see the solution →A student investigates the effect of pressure on two reactions:
(a)[3 marks]Reaction 1: Two solid powders are mixed together in a sealed container. Predict what happens to the rate of reaction if the pressure is increased. Explain your answer using particle theory.
(b)[2 marks]Reaction 2: Two liquids are mixed together. Explain, using your knowledge of particle arrangement, why increasing the pressure has little effect on the rate of reaction.
Question 15
2 marks · Hard
Answer and see the solution →A reaction takes place between two gases. The pressure is increased by decreasing the volume of the container.
Explain why this leads to a faster reaction rate, using ideas about particle collisions.
Question 16
2 marks · Hard
Answer and see the solution →State two features that are always true for catalysts when used in a chemical reaction.
Question 17
5 marks · Hard
Answer and see the solution →A student investigates the reaction below:
(a)[2 marks]Describe how the student could show that manganese(IV) oxide acts as a catalyst in this reaction.
(b)[2 marks]After the reaction, the student filters, dries, and reweighs the manganese(IV) oxide. The mass is unchanged. Explain why this result supports the conclusion that manganese(IV) oxide is a catalyst.
(c)[1 mark]State why only a small amount of catalyst is usually needed for a reaction.
Question 18
2 marks · Hard
Answer and see the solution →Explain why the same catalyst cannot usually be used for every type of chemical reaction.
Question 19
2 marks · Hard
Answer and see the solution →The diagram below shows a reaction profile for an exothermic reaction. The activation energy for the uncatalysed reaction is much larger than for the catalysed reaction.
Reaction profile for an exothermic reaction (uncatalysed and catalysed). Describe what the dashed line on this diagram represents. Explain how a catalyst causes this change.
Question 20
5 marks · Hard
Answer and see the solution →A student draws the following reaction profile diagram for a certain chemical reaction:
Reaction profile for a chemical reaction. Use the diagram to answer the questions below.
(a)[1 mark]State the term used for the energy difference from the reactants up to the peak without a catalyst.
(b)[2 marks]Describe how the diagram shows the effect of a catalyst on the reaction.
(c)[2 marks]Explain why many more particles in the reaction mixture can react when a catalyst is used, referring to the activation energy.