Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Reversible Reactions and Equilibria
144 practice questions
Topics covered
- Reversibility and dynamic equilibria19 practice questions
- Reversible reactions in a sealed container18 practice questions
- The position of equilibrium20 practice questions
- Changing the pressure19 practice questions
- Changing the temperature19 practice questions
- Adding a catalyst19 practice questions
- The effect of concentration19 practice questions
Practice questions
1–10 of 24 · Hard
Question 1
2 marks · Hard
Answer and see the solution →Explain, in terms of particle behaviour, why the concentrations of reactants and products remain constant in a sealed container when a reversible reaction has reached dynamic equilibrium.
Question 2
5 marks · Hard
Answer and see the solution →A reversible reaction between gases takes place in a sealed container.
(a)[2 marks]State two characteristics of the system when it has reached dynamic equilibrium.
(b)[3 marks]Explain what would happen to the amount of if the pressure on the system is increased, and relate your answer to the number of moles of gas on each side of the equation.
Question 3
2 marks · Hard
Answer and see the solution →Write a balanced symbol equation for the reversible thermal decomposition of ammonium chloride, including the correct symbol for a reversible reaction.
Question 4
2 marks · Hard
Answer and see the solution →State two essential features that define a sealed container in the context of reversible reactions.
Question 5
5 marks · Hard
Answer and see the solution →(a)[2 marks]Explain what happens to the forward and backward reaction rates when a reversible reaction first starts in a sealed container.
(b)[2 marks]Describe what is meant by equilibrium in this context.
(c)[1 mark]State one reason why equilibrium can only be reached if the container is sealed.
Question 6
2 marks · Hard
Answer and see the solution →In an experiment, solid ammonium chloride is heated in a sealed tube. Name the two gases that form, and state what happens when they meet in a cooler part of the tube.
Question 7
2 marks · Hard
Answer and see the solution →The equilibrium below is set up in a sealed container: \[ \ce{2X(g) <=> Y(g) + 2Z(g)} \] The forward reaction is exothermic. State and explain what will happen to the position of equilibrium if the temperature is increased.
Question 8
5 marks · Hard
Answer and see the solution →In a sealed container at equilibrium, the following reaction occurs:
The forward reaction is exothermic.
(a)[2 marks]State how an increase in pressure will affect the position of equilibrium. Explain your answer.
(b)[2 marks]Describe what happens to the position of equilibrium if the temperature is decreased. Explain your answer.
(c)[1 mark]If some AB(g) is removed from the container, what will happen to the amounts of A2(g), B2(g), and AB(g) as the system re-establishes equilibrium? Explain.
Question 9
2 marks · Hard
Answer and see the solution →For the reversible reaction in a sealed container: \[ \ce{C(g) <=> D(g) + E(g)} \] Give one change that would cause the position of equilibrium to shift to the right. Explain your answer.
Question 10
2 marks · Hard
Answer and see the solution →Consider the following reversible reaction, which takes place in a sealed vessel at constant temperature:
Explain why changing the pressure will or will not affect the position of equilibrium for this reaction.