What is Le Chatelier's principle?

Le Chatelier's principle illustrates how a system at equilibrium reacts to external changes. It states that if a dynamic equilibrium is disturbed by changing the conditions, such as concentration, temperature, or pressure, the system will respond by shifting its position to partially counteract the change and restore a new equilibrium. This means that for a given chemical reaction at equilibrium, if the concentration of a reactant or product is increased, the reaction will shift in the direction that consumes that reactant or product. Similarly, if the temperature is increased, the system will shift in the direction that absorbs heat, and if pressure is changed, the equilibrium will shift towards the side with fewer moles of gas.

The other options do not accurately characterize Le Chatelier's principle. The idea that equilibrium cannot be disturbed is a misunderstanding of the principle, as it is precisely about how equilibrium can be affected. The description of the principle as relating to reaction rates focuses instead on kinetics rather than equilibrium shifts, and predicting energy changes is a separate concept centered on thermodynamics rather than the response of equilibrium to disturbances.