The effects that temperature has on the equilibrium position of a reaction can also be explained by using Le Chtelier's Principle.

Recall that in an exothermic reaction, heat is given off. Therefore, heat can be considered to be a product:
A + B -> C + D + Heat

On the other hand, in an endothermic reaction, heat is absorbed. Therefore, heat can be considered to be a reactant:
A + B + Heat -> C + D

Consequently, increasing the temperature (or adding heat) shifts exothermic reactions to the left, and increasing temperature (or adding heat) shifts endothermic reactions to the right. As these reactions proceed in such a manner to minimize the change in temperature, we can see Le Ch->telier's Principle in action.

Let's consider an example. Nitrogen dioxide, NO₂, a dark brown gas, exists in equilibrium with dinitrogen tetroxide, N₂O₄, a colorless gas, as shown in the following chemical reaction:

N₂O₂ + Heat -> 2NO₂
       Pale Brown       Dark Brown

Applying Le Chtelier's Principle to the above reaction, we would expect that increasing the temperature (adding heat) would favor the production of the dark brown NO₂ gas. Conversely, decreasing the temperature (removing heat) would favor the production of the pale brown N₂O₂ gas.