Le Chatelier's Principle
When a system at equilibrium is disturbed, it responds in the direction that partially opposes the disturbance.
Unit
Dimensionless
In depth
The principle provides a qualitative prediction for changes in concentration, pressure and temperature without any calculation. It is a consequence of the system re-minimising its Gibbs energy under the new constraints, and it never fully cancels the disturbance — only reduces it.
Examples in the real world
Compressing the N₂O₄/NO₂ mixture darkens it briefly, then lightens as equilibrium shifts to fewer gas molecules.