Altering Conditions

• Reversible reactions are exothermic in one direction and endothermic in the other direction
• Increasing the temperature favours the reaction in the endothermic reaction. The equilibrium shifts as if to lower the temperature by taking in energy
• So decreasing the temperature favours the endothermic reaction

• If the forward reaction is exothermic:
• an increase in temperature decreases the amount of product formed
• a decrease in temperature increases the amount of product formed

• If the forward reaction is endothermic:
• an increase in temperature will increase the amount of product formed
• a decrease in temperature will decrease the amount of product forme

If we change the conditions of a system at equilibrium, the posotion of equilibrium shifts to try and cancel out the change.

• If the forward reaction produces more molecules of gas:
• an increase in pressure decreases the amount of product formed
• a decrease in pressure increases the amount of product formed

• If the forward reaction produces fewer molecules of gas (like the Haber process):
• an increase in pressure increases the amount of product formed
• a decrease in pressure decreases the amount of product formed