Substance P changes reversibly into substance Q in a closed flask. The change from P to Q is the forward reaction. Each experiment starts with the same amounts of P and Q, and only the temperature is changed.
The table shows the percentage of the equilibrium mixture that is Q.
| Temperature in ∘C^\circ\text{C}∘C | Percentage of Q in the equilibrium mixture in % |
|---|---|
| 290 | 24 |
| 390 | 39 |
| 490 | 57 |
| 590 | 72 |
Which statement about the forward reaction and the reaction rate at 290 ∘C^\circ\text{C}∘C is correct?
The forward reaction is endothermic, and the reaction rate is lower than at 590 ∘C^\circ\text{C}∘C.
The forward reaction is exothermic, and the reaction rate is higher than at 590 ∘C^\circ\text{C}∘C.
The forward reaction is exothermic, and the reaction rate is lower than at 590 ∘C^\circ\text{C}∘C.
The forward reaction is endothermic, and the reaction rate is higher than at 590 ∘C^\circ\text{C}∘C.
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.