Equilibria, Le Chatelier’s principle and Kc

• In a reversible reaction at equilibrium:

  • forward and reverse reactions proceed at equal rates
  • the concentrations of reactants and products remain constant
• a dynamic equilibrium can only happen in a closed system
• A catalyst does not affect the position of equilibrium
• A homogeneous reaction is a chemical reaction where all the reactants and products are in the same phase
• Le Chatelier's principle can be used to predict the effects of changes in temperature, pressure and concentration on the position of equilibrium in homogeneous reactions
• The value of the equilibrium constant is not affected either by changes in concentration or addition of a catalyst
• equation for Kc

  
• if you add heat to a reversible reaction the equilibrium will shift to favour the endothermic reaction to absorb the heat
• if you remove heat from a reversible reaction the equilibrium will shift to favour the exothermic reaction to release heat