Explain Le Chatelier's Principle

In a chemical equilibrium, the position of the equilibrium will always move to oppose any change in temperature, pressure or concentration of reactants/products. For example, if temperature is increased, the equilibrium will shift in favour of the endothermic side of the equation in order to reduce the temperature. If pressure is increased (in a gaseous state), the equilibrium will move to favour the side of the reaction with fewer molecules in order to reduce the pressure. The same is true of concentration for an equilibrium in the liquid state.