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
11–20 of 57 · Easy
Question 11
3 marks · Easy
Answer and see the solution →A student records the number of red and green squares at different times in a sealed container during a reversible reaction.
Time (s) Red squares Green squares 0 40 0 1 30 10 2 23 17 3 19 21 (a)[1 mark]How many total squares are there in the container at each recorded time?
(b)[1 mark]What does this suggest about the system in the container?
(c)[1 mark]State what feature of the container ensures this result in a reversible reaction.
Question 12
1 mark · Easy
Answer and see the solution →State what term is used when the rate of the forward reaction equals the rate of the backward reaction in a sealed system.
Question 13
3 marks · Easy
Answer and see the solution →When heating ammonium chloride in a sealed test tube, a reversible reaction takes place.
(a)[1 mark]Write a chemical equation to show the decomposition of ammonium chloride on heating.
(b)[1 mark]State the names of the products formed during the decomposition.
(c)[1 mark]Give a reason why the reaction is reversible.
Question 14
1 mark · Easy
Answer and see the solution →State the chemical formula of the white solid that forms when ammonia and hydrogen chloride gases react together in a sealed tube.
Question 15
2 marks · Easy
Answer and see the solution →A reversible reaction occurs in a sealed container. At the start, there are 80 blue squares representing reactant molecules. Every second, one fifth of the blue squares turn yellow (product molecules). After one second, how many blue squares remain? Show your calculation.
Question 16
1 mark · Easy
Answer and see the solution →State what happens to the position of equilibrium if the pressure is increased for a reaction in which the number of moles of gas is greater on the left side of the equation than on the right.
Question 17
3 marks · Easy
Answer and see the solution →The following reversible reaction occurs in a sealed container:
The forward reaction is exothermic.
(a)[1 mark]State whether the position of equilibrium will move to the left or the right if the temperature is increased.
(b)[2 marks]Explain your answer to part (a).
Question 18
2 marks · Easy
Answer and see the solution →Consider the equilibrium reaction in a sealed container:
The forward reaction is exothermic. The system is at equilibrium at 400 K and 2 atm pressure.
Calculate the qualitative effect (increase, decrease or no change) on the amount of at equilibrium if:
(a) the temperature is decreased, but the pressure is kept constant.
(a)[2 marks]State the effect on at equilibrium and explain your answer.
Question 19
2 marks · Easy
Answer and see the solution →The reversible reaction below is in a sealed container at equilibrium:
There are equal numbers of moles of gas on both sides of the equation, and the forward reaction is endothermic.
Explain, with a reason, the effect on the position of equilibrium if the pressure is increased.
Question 20
1 mark · Easy
Answer and see the solution →In a reversible reaction in a sealed container, what happens to the concentrations of reactants and products at equilibrium?