Hydrogen iodide decomposes reversibly to form hydrogen and iodine in a sealed container. The forward reaction is endothermic. The mixture has reached equilibrium and is then cooled.
Which statement describes the change in the amount of hydrogen iodide when a new equilibrium is reached?
The amount stays constant because both reactions continue at equal rates.
The amount increases because cooling favours the exothermic reverse reaction.
The amount increases because cooling favours the endothermic reverse reaction.
The amount decreases because cooling favours the endothermic forward reaction.
109 exam-style questions on AQA GCSE Chemistry 6.2 Reversible reactions and dynamic equilibrium, covering 6.2.1 Reversible reactions, 6.2.2 Energy changes and reversible reactions, 6.2.3 Equilibrium, 6.2.4 The effect of changing conditions on equilibrium, 6.2.5 The effect of changing concentration, 6.2.6 The effect of temperature changes on equilibrium, and 6.2.7 The effect of pressure changes on equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.