Elizabeth Odeleye
The effect of concentration on equilibrium
If the concentration of a reactant is increased the equilibrium will shift in the direction of the reaction that uses the reactants, so that the reactant concentration decreases. The forward reaction is favoured.
The forward reaction is also favoured if the concentration of the product is decreased, so that more product is formed.
If the concentration of a reactant is decreased the equilibrium will shift in the direction of the reaction that produces the reactants, so that the reactant concentration increases. The reverse reaction is favoured.
The reverse reaction is also favoured if the concentration of the product is increased, so that product is used.
The effect of temperature on equilibrium
An increase in temperature:
Favours the endothermic reaction because it takes in energy (cools the container).
The reverse reaction is endothermic, so the reverse reaction is favoured.
A decrease in temperature:
Favours the exothermic reaction because it releases energy (warms the container).
The forward reaction is exothermic, so the forward reaction is favoured.
The effect of pressure on equilibrium
An increase in pressure will:
Favour the reaction that decreases the number of gas molecules.
There are fewer molecules of product gas than reactant gas, so the forward reaction is favoured.
A decrease in pressure will:
Favour the reaction that increases the number of gas molecules.
There are more molecules of reactant gas, so the reverse reaction is favoured.