Hydrogen iodide decomposes reversibly in a sealed vessel.
2HI(g)⇌H2(g)+I2(g) 2\text{HI(g)} \rightleftharpoons \text{H}_2\text{(g)} + \text{I}_2\text{(g)} 2HI(g)⇌H2(g)+I2(g)The decomposition of hydrogen iodide is endothermic. The mixture is allowed to reach equilibrium at 500 ∘C500\ ^\circ\text{C}500 ∘C.
The mixture is cooled to 400 ∘C400\ ^\circ\text{C}400 ∘C and allowed to reach equilibrium again. A greater amount of hydrogen iodide is then present.
Explain this change.
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.