Chemical Equilibrium & Le Chatelier
Chemical equilibrium refers to the state in a reversible chemical reaction where the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. Le Chatelier’s Principle states that if an external change, such as concentration, temperature, or pressure, is applied to a system at equilibrium, the system will adjust itself to partially counteract the change and re-establish equilibrium, shifting the reaction accordingly.
Chemical Equilibrium & Le Chatelier
Chemical equilibrium refers to the state in a reversible chemical reaction where the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. Le Chatelier’s Principle states that if an external change, such as concentration, temperature, or pressure, is applied to a system at equilibrium, the system will adjust itself to partially counteract the change and re-establish equilibrium, shifting the reaction accordingly.
💡 Key Takeaways
- Define chemical equilibrium as the state in a reversible reaction where forward and reverse rates are equal and concentrations stop changing.
- Learn how Le Chatelier’s Principle predicts the system’s response to external changes in concentration, temperature, and pressure by shifting the equilibrium.
- Explore how adding or removing reactants or products moves the equilibrium position and how the reaction quotient governs this shift.
- Understand how temperature affects equilibrium differently for exothermic and endothermic reactions, and how pressure impacts gaseous equilibria when the number of moles changes.
❓ Frequently Asked Questions
What is chemical equilibrium?
Chemical equilibrium is the state in a reversible reaction where the forward and reverse reaction rates are equal, so the concentrations of reactants and products remain constant over time.
What does Le Chatelier’s Principle state in simple terms?
Le Chatelier’s Principle says that if a system at equilibrium is disturbed by changes in concentration, temperature, or pressure, the system shifts to counteract the disturbance and re-establish a new equilibrium.
How does changing concentration affect the equilibrium position?
Increasing the concentration of a reactant shifts the equilibrium toward products; increasing the concentration of a product shifts it toward reactants. Conversely, removing reactants or products shifts the equilibrium in the opposite direction.
How does temperature affect equilibrium for exothermic and endothermic reactions?
For an exothermic reaction, increasing temperature shifts the equilibrium toward reactants. For an endothermic reaction, increasing temperature shifts toward products. Decreasing temperature has the opposite effects.
Does a catalyst change the position of equilibrium?
No. A catalyst speeds up both forward and reverse reactions equally, so it helps reach equilibrium faster but does not change the equilibrium composition.