Le Chatelier's principle is a useful guideline that can be used to predict how a reaction will shift when the system is disturbed. Le Chatelier’s principle states that, if a chemical system in dynamic equilibrium experiences a change, such as a change in the concentration of one of the reactants or products or a change in temperature, then the equilibrium will shift to minimize the effects of this change.

Chemists can measure the concentrations of reactants and products in a reaction experimentally. If a reaction experiences a disturbance, such as the addition of a substance or a change in temperature, the reaction will shift to counteract the effects of the disturbance by changing the concentrations of reactants and products. These changes can then be detected experimentally. Le Chatelier’s principle has been used to predict the change in the position of a reaction’s equilibrium in response to a disturbance for many different chemical reactions and conditions.