Le Chatelier's Principle

A qualitative rule stating that a system at chemical equilibrium, when subjected to a change in concentration, temperature, pressure or other external condition, will shift in the direction that tends to partially counteract that change.

A qualitative thermodynamic guideline stating that a system at chemical equilibrium will respond to an external perturbation (change in concentration, temperature, pressure, or other intensive parameter) by shifting its equilibrium position in a direction that tends to partially counteract the imposed change, provided the system can reach a new equilibrium under the applied constraints.

A qualitative thermodynamic heuristic stating that a system at equilibrium, when subjected to an external change (e.g., in concentration of a species, pressure, volume, or temperature), will shift in a direction that tends to oppose the imposed change; the principle predicts only the direction of the shift, not its magnitude or rate, and does not replace quantitative thermodynamic analysis.