Le Chatelier's Principle

In 1884, Henri-Lewis Le Chatelier made observations that led to his famous principle of equilibrium. His observation can be stated:  A stress on a system that is at equilibrium will cause a shift in the equilibrium position such that the effect of the stress is lessened.

Chemical Equilibrium

You know that reactants in a chemical reaction proceed on to products. Sometimes, though, the reactants are not completely consumed because the reaction stops, leaving a certain amount of products and a certain amount of reactants.