The reaction A ⇌ \rightleftharpoons\,⇌ B takes place in a closed vessel. The percentage yield of B at equilibrium was measured at different temperatures.
| Temperature in ∘ ^\circ\,∘C | Percentage yield of B |
|---|---|
| 20 | 25 |
| 40 | 41 |
| 60 | 59 |
Explain what the results show about the energy change in the forward reaction. The equilibrium mixture at 60 ∘ ^\circ\,∘C is cooled to 10 ∘ ^\circ\,∘C. Predict and explain whether the percentage yield of B will increase or decrease when a new equilibrium is reached.
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.