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
91–100 of 144
Question 91
2 marks · Normal
Answer and see the solution →Explain what happens to the position of equilibrium when temperature is increased in a reversible reaction.
Question 92
4 marks · Normal
Answer and see the solution →The equation below shows a reversible reaction.
(a)[1 mark]Is the forward reaction exothermic or endothermic? Explain your answer.
(b)[2 marks]Predict what happens to the position of equilibrium if the temperature is decreased. Explain your answer.
(c)[1 mark]Which direction (left or right) is favoured when temperature is increased? Explain.
Question 93
2 marks · Hard
Answer and see the solution →A reversible reaction is at equilibrium. The forward reaction is exothermic. Explain what happens to the position of equilibrium if the temperature is increased.
Question 94
5 marks · Hard
Answer and see the solution →The following reversible reaction is at equilibrium:
(a)[2 marks]State whether the forward reaction is exothermic or endothermic. Explain how you know.
(b)[3 marks]If the position of equilibrium shifts to the right when the temperature is changed, is the temperature being increased or decreased? Explain your reasoning using the ΔH value.
Question 95
2 marks · Hard
Answer and see the solution →For the following equilibrium reaction:
State how increasing the temperature will affect the position of equilibrium. Give your answer for both cases: (i) forward reaction is exothermic; (ii) forward reaction is endothermic.
Question 96
1 mark · Easy
Answer and see the solution →State the effect of adding a catalyst on the position of equilibrium in a reversible chemical reaction.
Question 97
3 marks · Easy
Answer and see the solution →(a)A reversible reaction mixture is at equilibrium. A catalyst is added to the system.
Explain what happens to:
(i)[1 mark]the rate at which the equilibrium is reached,
(ii)[1 mark]the position of equilibrium,
(iii)[1 mark]the amount of products at equilibrium.
Question 98
2 marks · Easy
Answer and see the solution →In a reversible reaction at equilibrium, the rate of the forward reaction is 0.6 mol/dm³/s and the rate of the reverse reaction is also 0.6 mol/dm³/s. A catalyst is added and both rates are increased by a factor of 5.
Calculate the new rate of the forward reaction, and state whether the position of equilibrium will change.
Question 99
2 marks · Easy
Answer and see the solution →A student claims that adding a catalyst to a reversible reaction will result in more products being formed at equilibrium. Explain, with reasons, whether the student is correct.
Question 100
3 marks · Easy
Answer and see the solution →The concentrations of reactants and products in a reversible reaction at equilibrium are measured every minute. At minute 4, a catalyst is added. The concentrations at each minute are shown below.
Concentration data (mol/dm³) Time (min) [Reactant] [Product] 0 1.00 0.00 1 0.85 0.15 2 0.75 0.25 3 0.71 0.29 4 0.70 0.30 5 0.70 0.30 6 0.70 0.30 (a)[1 mark]Describe the effect of adding the catalyst on the time taken to reach equilibrium.
(b)[1 mark]Use the data to state the concentrations at equilibrium.
(c)[1 mark]Does adding the catalyst change the equilibrium concentrations? Explain your answer.