Hydrogen reacts with iodine in a reversible reaction.
H2(g)+I2(g)⇌2HI(g)\text{H}_2\text{(g)} + \text{I}_2\text{(g)} \rightleftharpoons 2\text{HI(g)}H2(g)+I2(g)⇌2HI(g)
The same starting amounts are placed in two identical sealed containers. The table shows the percentage of the hydrogen converted into hydrogen iodide at equilibrium.
| Temperature in °C | Hydrogen converted in % |
|---|---|
| 350 | 79 |
| 500 | 76 |
What does this show?
Heating favours the direction that transfers energy to the surroundings.
The reverse reaction is slower at 500 °C than at 350 °C.
Forming hydrogen iodide takes in energy from the surroundings.
Forming hydrogen iodide transfers energy to the surroundings.
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.