Summary
Dynamic equilibria involve reversible reactions where the forward and reverse reactions occur at the same rate, resulting in constant concentrations of reactants and products.
- Reversible Reaction — a chemical reaction where the reactants form products that, in turn, react together to give the reactants back. Example: The Haber Process for ammonia production is a reversible reaction.
- Equilibrium — the state in a reversible reaction where the forward and reverse reactions occur at the same rate. Example: In the Haber Process, equilibrium is reached when the rate of formation of ammonia equals the rate of its decomposition.
- Le Chatelier's Principle — states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change. Example: Increasing pressure in the Haber Process shifts equilibrium towards ammonia production.
Exam Tips
Key Definitions to Remember
- Reversible Reaction
- Equilibrium
- Le Chatelier's Principle
Common Confusions
- Equilibrium does not mean equal concentrations of reactants and products.
- High pressure favors the formation of fewer moles of gas, not necessarily more products.
Typical Exam Questions
- What happens to the position of equilibrium when temperature is increased? It shifts in the direction that absorbs heat (endothermic direction).
- How does increasing pressure affect the Haber Process? It increases the yield of ammonia.
- What is Le Chatelier's Principle? It predicts how a change in conditions affects the position of equilibrium.
What Examiners Usually Test
- Understanding of how changes in temperature, pressure, and concentration affect equilibrium.
- Application of Le Chatelier's Principle to predict changes in equilibrium position.