Equilibria

• Reversible reactions will reach equilibrium.
• 3 things affecting the position of Equilibrium:

  • Temperature
  • Pressure
  • Concentrations
• Concentration of reactants > concentration of products

  • Equilibrium lies left

  Concentration of reactants < concentration of products

  • Equilibrium lies right
• Le Chatelier's principle


  States that if there is a change in concentration, temperature or pressure in a reversible reaction, the equilibrium moves to help counteract that change.
• Equilibrium: Temperature

  Decrease the temperature

  • Equilibrium moves in the exothermic direction (to produce more heat)

  Increase the temperature

  • Equilibrium moves in endothermic direction (to absorb the extra heat)
• Equilibrium: Pressure

  Increase the pressure

  • equilibrium moves towards side with less moles (to reduce pressure)

  Decrease the pressure

  • equilibrium moves towards side with more moles (to increase pressure)
• Equilibrium: Concentration

  Increase the concentration of the reactants

  • Equilibrium shifts right to use up reactants

  Decrease the concentration of the products

  • Equilibrium shifts left to use up the products