10.4 Dynamic equilibrium and Le Chatelier's Principle

• Reverse reactions have both forward and backward reactions occurring at the same time
• At equilibrium

  • forward and backward reactions happening at the same rate
  • concentrations of forward and backward reactions stay constant
• Le Chatelier's Principle: when a system in dynamic equilibrium is subjected to a change in conditions, the equilibrium position shifts to minimise the change
• Increasing concentration of reactants shifts position of equilibrium in favour of forward reaction
• Increasing concentration of products shifts position of equilibrium in favour of the backward reaction
• Increasing temperature favours the endothermic reaction
• Decreasing temperature favours the exothermic reaction
• Increasing pressure shifts equilibrium to favour the side with fewer gaseous molecules
• Decreasing pressure shifts equilibrium to favour the side the more gaseous molecules
• Changing pressure only affects reactions involving gaseous molecules
• Catalysts increase the rate of both reactions so doesn't affect position of equilibrium