Topic 7

Dynamic equilibrium

A closed system with equal rate and concentration of forward and reverse reactions.

Closed system

matter and energy can’t be lost or gained

Open system

Matter and energy can escape

Effect of pressure on equilibrium

increase = equilibrium shifts to side with less volume/number of molecules

Effect of concentration on equilibrium

increase = forward reaction is favored

Effects of temperature on equilibrium

increase = endothermic reaction is favored

only factor effecting Kc

effect of Catalyst on equilibrium

Increase rate of both reactions

No effect on equilibrium

Kc > 1

concentration of product is greater

What factor effects Kc?

Temperature

What happens to Kc if you reverse the equation?

It becomes the reciprocal

What is Q?

Ratio of products and reactants for a reaction that hasn’t reached equilibrium

What is the relationship between Q and Kc at equilibrium?

Q=Kc

What happens if Q>Kc?

The reverse reaction is favored

What happens if Q

The forward reaction is favored

Le Chatelier principle

If a change is made to a system at dynamic equilibrium, the position of the equilibrium moves to minimise this change

What happens to Kc when reaction coefficients are doubled?

Kc is squared

What happens to Kc when reaction coefficients are halved?

Kc is square rooted

What happens to Kc if 2 reactions are added?

The Kc values are multiplied