Le Châtelier’s principle tells us that if a change is made to a system that is in equilibrium, the balance between the forward and reverse reactions will shift to offset this change and return the system to equilibrium.
The following conditions affect equilibrium:
- Concentration (aqueous) — if there are more reactants, the reaction will shift to the right. Corresponding increases or decreases in reactants or products will shift based on this principle above.
- Changes in temperature are the only condition that changes . If the system is heated, it goes in the endothermic direction and if it is cooled, it will go towards the exothermic direction. In other words, if the system is heated, it will cool itself and vice versa.
- Pressure/volume — the system will take the position with less moles. If there are the same number of moles on both sides, there will be no change. An increase in pressure/decrease in volume takes the position of less moles. A decrease in pressure/increase in volume takes the position of more moles.
- Catalysts take no change, and will catalyse both directions equally.