3.3 Le chatelier's principle

what is Le Chatelier’s Principle

Le Chatelier’s Principle states that a system at equilibrium that is disrupted, will oppose the disruption by either shifting to the right or left in effort to re-establish equilibrium.

What happens when there is a change in concentration

If the concentration of product increases, Le Chatelier's principle predicts that the reverse rate of reaction will increase to consume more product, and thus more reactant will be produced, causing the equilibrium to shift to the left.

Vice versa for an increase in concentration of reactant.

If the concentration of product decreases, Le Chatelier’s principle predicts that the forward rate of reaction will increase to replenish lost product, causing the equilibrium to shift to the right.

What happens when there is a change in volume

For GASEOUS reactions only, if the volume decreases and the pressure increases, the equilibrium will shift to whichever side has the least amount of moles of gas to compensate for lost volume.

Vice versa for volume increase.

What happens when there is a change in temperature

If the temperature increases, the speed of the endothermic rate of reaction will increase, causing the equilibrium to lean in whichever direction it points.

Vice versa for temp decrease.

How does adding aid a disrupted system

Adding a catalyst speed up the forward rate of reaction to the same degree as the reverse rate of reaction, thus allowing the system to gain equilibrium quicker but not affecting its position.