The forward reaction shown is exothermic. In industry the reaction is carried out at about 450 ∘C450\ ^\circ\text{C}450 ∘C, which is much higher than the temperature that gives the best yield.
N2(g)+3H2(g)⇌2NH3(g)\text{N}_2\text{(g)} + 3\text{H}_2\text{(g)} \rightleftharpoons 2\text{NH}_3\text{(g)}N2(g)+3H2(g)⇌2NH3(g)
Why is this higher temperature used?
A higher temperature increases the yield of ammonia at equilibrium
A higher temperature shifts the position of equilibrium to the right
A higher temperature gives a lower yield but a much faster rate
A higher temperature allows a much lower pressure to be used
40 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.