The Effect of Temperature Changes on Equilibrium (AQA GCSE Chemistry Combined Science): Revision Notes
📚 Revision Notes
6.2.6 The Effect of Temperature Changes on Equilibrium
Temperature changes have a significant effect on the position of equilibrium in reversible reactions. According to Le Chatelier's Principle, if the temperature is changed, the equilibrium will shift to counteract that change. The effect of temperature depends on whether the reaction is exothermic (releases heat) or endothermic (absorbs heat).
In exothermic reactions (where heat is released):
- Increasing the temperature: The equilibrium shifts to the left (towards the reactants) to absorb the extra heat. This reduces the amount of products.
- Decreasing the temperature: The equilibrium shifts to the right (towards the products) to release heat, increasing the amount of products.
In endothermic reactions (where heat is absorbed):
- Increasing the temperature: The equilibrium shifts to the right (towards the products) to absorb the added heat, increasing the amount of products.
- Decreasing the temperature: The equilibrium shifts to the left (towards the reactants), reducing the amount of products, as less heat is available for the reaction.
lightbulbExample
Example: In the reaction for the formation of ammonia:
- This is an exothermic reaction.
- If the temperature is increased, the equilibrium will shift to the left, reducing ammonia production.
- If the temperature is decreased, the equilibrium will shift to the right, producing more ammonia.
infoNote
Raising the temperature favours the endothermic direction (to absorb heat), and lowering the temperature favours the exothermic direction (to release heat).