Equilibria

Conditions for equilibrium:

• reaction takes place in a closed system

• Equilibrium can be approached from either direction and the final position will be the same

• Equilibrium is a dynamic process

• Equilibrium is reached when the macroscopic properties of the system do not change over time

What is Le Chatelier’s principle:

If a system at equilibrium is disturbed, the equilibrium moves in the direction that tends to reduce the disturbance

if the reactant’s concentration increased, then:

• equilibrium will shift to the right

• To oppose the change in concentration

• Increases number of moles of the products

if the pressure of the reactants increase, then:

• equilibrium will shift to the right to decrease pressure

• To oppose the change in pressure

• Increase the number of moles of the product

• ONLY if all substances are in a gaseous state

If increasing the temperature of a reaction, then:

• exothermic reaction will increase

• Equilibrium shifts in the direction that cools the system down

What are the characteristics of a dynamic equilibrium?

• Forward and backward reaction is the same

• Rate remains constant

• Closed system

What is K_c?

• value of the ratio of product concentrations to reactant concentrations at equilibrium in a reversible reaction

If there is a catalyst in a reversible reaction, then:

• no change to the position of equilibrium

• No change to the Kc value

• This is because a catalyst increases the rate of the forward and backward reaction equally