4.4 Equilibrium

dynamic equilibrium Def

amounts of each reactant and product remain constant and rate of reverse reaction

Position of equilibrium on product

equilibrium lies to the left, little product formed.

right, lots of product

Le Chatelier's principle

if a change is made to conditions of a system at equilibrium, then position of equilibrium moves to oppose that change in condition

Increase concentration of reactant on equilibrium

causes the equilibrium to move to the right in order to use up the reactant

Increase temp

Increasing the temperature of an exothermic reaction will cause the equilibrium move to the left as the endothermic reverse reaction is favoured

increase Pressure on equilibrium

Increasing pressure caused equilibrium to move to side with fewer gas particles in order to decrease pressure

Catalyst Added on equilibrium

No effect on position of equilibrium-speeds up both forward and reverse reactions

Kc meaning

Equilibrium constant

Kc expression

Products over reactants

high Kc value (>1) Indicates what

position of equilibrium lies to right-hand side.

low Kc value (<1) indicates

position of equilibrium lies to left-hand side.

What affects Kc value

Temperature not pressure or catalyst

Temperature on Kc

• Kc is affected by changes in temperature

• As T increases Kc decreases

• forward reaction is Exothermic