Sulfur trioxide is made by the reversible reaction:
2SO2(g)+O2(g)⇌2SO3(g)2\text{SO}_2\text{(g)} + \text{O}_2\text{(g)} \rightleftharpoons 2\text{SO}_3\text{(g)}2SO2(g)+O2(g)⇌2SO3(g)
The table shows results obtained at the same pressure.
| Temperature in ∘C^\circ\text{C}∘C | Equilibrium yield of sulfur trioxide in % | Initial rate of formation of sulfur trioxide in mol/s\text{mol/s}mol/s |
|---|---|---|
| 350 | 98 | 0.006 |
| 450 | 92 | 0.020 |
| 550 | 74 | 0.055 |
Explain what the data show about the energy change of the forward reaction.
The process must have an equilibrium yield of at least 90% and an initial rate of at least 0.015 mol/s.
Which temperature should be used?
Justify your answer.
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.