A teacher sets up a reversible reaction in a sealed flask. In the reaction a pink cobalt compound changes into a blue cobalt compound.
pink cobalt compound ⇌ \rightleftharpoons\,⇌ blue cobalt compound
The forward reaction is endothermic.
State what is meant by an endothermic reaction.
The teacher places the flask in a beaker of hot water. Predict the colour of the mixture in the flask. Give a reason for your answer.
The teacher then places the flask in a beaker of ice. Predict the colour change seen.
The table shows the colour of the mixture at different temperatures.
| Temperature / °C | Colour of mixture |
|---|---|
| 10 | pink |
| 30 | pink |
| 50 | purple |
| 70 | blue |
| 90 | blue |
Use the table to give the lowest temperature at which the mixture was blue.
State one condition, other than temperature, that can change the position of an equilibrium.
45 exam-style questions on Edexcel GCSE Chemistry 5.2 Reversible reactions and equilibria, covering 5.2.1 Reversible reactions and dynamic equilibrium, 5.2.2 The Haber process, and 5.2.3 Changing the position of a dynamic equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.