Ch. 16 Equilibrium: Le Chatelier's Principle

These flashcards cover the key concepts of Le Chatelier's Principle, focusing on how changes in temperature, pressure, and concentrations of reactants or products affect chemical equilibria.

What does Le Chatelier's Principle state about a system at equilibrium when disturbed?

The system will shift in a direction that counteracts the disturbance to reestablish equilibrium.

What is the effect of adding a catalyst to a reaction at equilibrium?

Catalysts increase the rate at which equilibrium is reached but do not change the position of the equilibrium or the equilibrium constant (K).

How is heat categorized for an exothermic reaction?

Heat is a product. (\Delta H < 0)

How is heat categorized for an endothermic reaction?

Heat is a reactant. (\Delta H > 0)

How does an increase in temperature affect equilibrium?

The equilibrium shifts in the endothermic direction (to absorb the added heat).

How does a decrease in temperature affect equilibrium?

The equilibrium shifts in the exothermic direction (to release heat).

When a reactant is added to a system at equilibrium, how does the equilibrium shift?

The equilibrium shifts to the right (towards products) to consume the added reactant.

When a reactant is removed from a system at equilibrium, how does the equilibrium shift?

The equilibrium shifts to the left (towards reactants) to replenish the removed reactant.

When a product is added to a system at equilibrium, how does the equilibrium shift?

The equilibrium shifts to the left (towards reactants) to consume the added product.

When a product is removed from a system at equilibrium, how does the equilibrium shift?

The equilibrium shifts to the right (towards products) to replenish the removed product.

How does an increase in pressure (or decrease in volume) affect equilibrium for gaseous reactions with different moles of gas?

The equilibrium shifts towards the side with fewer moles of gas to relieve the pressure.

How does a decrease in pressure (or increase in volume) affect equilibrium for gaseous reactions with different moles of gas?

The equilibrium shifts towards the side with more moles of gas to resist the pressure decrease.

What is the effect of adding an inert gas at constant volume to an equilibrium system?

There is no effect on the equilibrium position because the partial pressures of reactants and products remain unchanged.