7.1.2—Le Chatelier’s principle as: if a change

When a system at equilibrium is disturbed, it shifts in the direction that opposes the disturbance, partially restoring the balance.

For concentration changes, the system consumes an added reactant or replaces a removed product. For pressure changes in gases, it favours the side with fewer gas molecules; temperature must be treated as heat in the equation.

For N₂ + 3H₂ ⇌ 2NH₃, adding H₂ shifts right, while increasing pressure also shifts right because four gas moles become two.

A catalyst changes how quickly equilibrium is reached, not the equilibrium position. “Opposes” does not mean the disturbance is completely cancelled.