Study Notes
In equilibrium, some reactions go to completion while others are reversible, allowing products to reform reactants. In a dynamic equilibrium, the rates of forward and backward reactions are equal, maintaining constant concentrations in a closed system. The equilibrium constant (Kc) relates the concentrations of reactants and products at equilibrium, and its value indicates the position of equilibrium. Le Chatelier's principle predicts how changes in conditions affect equilibrium position.
Exam Tips
Key Definitions to Remember
- Dynamic equilibrium: A state where the forward and reverse reactions occur at the same rate.
- Equilibrium constant (Kc): A value that expresses the ratio of concentrations of products to reactants at equilibrium.
- Le Chatelier's principle: The principle that predicts the shift in equilibrium position in response to changes in concentration, pressure, or temperature.
Common Confusions
- Confusing the effects of catalysts on equilibrium position.
- Misunderstanding the difference between open and closed systems.
Typical Exam Questions
- What happens to the equilibrium position if the concentration of a reactant is increased? The equilibrium shifts to the right to produce more products.
- How does a catalyst affect the equilibrium constant? A catalyst does not affect the equilibrium constant; it only speeds up the rate at which equilibrium is reached.
- What is the effect of increasing temperature on an exothermic reaction? The equilibrium shifts to the left, favoring the reactants.
What Examiners Usually Test
- Understanding of how changes in conditions affect equilibrium position.
- Ability to write and interpret equilibrium expressions.
- Application of Le Chatelier's principle to predict shifts in equilibrium.