Le Chatelier's Principle

Le Chatelier's Principle states that when a system at equilibrium is disturbed, it shifts to partially counteract the disturbance and restore a new equilibrium.

Adding a reactant or removing a product shifts equilibrium toward the products (forward). Removing a reactant or adding a product shifts it toward the reactants (reverse). The system adjusts to reduce the disturbance.

Increasing temperature favors the endothermic direction. Decreasing temperature favors the exothermic direction. Think of heat as a reactant (endothermic) or product (exothermic).

No. A catalyst speeds up both the forward and reverse reactions equally, so the system reaches equilibrium faster but the equilibrium position (ratio of products to reactants) does not change.