The table shows the percentage yield of ammonia at equilibrium at a pressure of 200 atmospheres and four temperatures. What do the data show about the forward reaction, and what is the disadvantage of using the lowest temperature?
Table: The percentage yield of ammonia at equilibrium at a pressure of 200 atmospheres and four temperatures
| Temperature in ∘C^\circ\text{C}∘C | Percentage yield of ammonia in % |
|---|---|
| 300 | 62 |
| 400 | 38 |
| 500 | 20 |
| 600 | 10 |
It is endothermic, and at the lowest temperature the rate is very slow
It is endothermic, and at the lowest temperature the yield is very low
It is exothermic, and at the lowest temperature the yield is very low
It is exothermic, and at the lowest temperature the rate is very slow
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.