# What is Le Chatelier's principle for systems in equilibrium?

Aug 16, 2016

Le Chatelier's principle states that when a system at equilibrium is subjected to an external perturbation, the equilibrium will move so as to offset the external perturbation.

#### Explanation:

To put this another way if an equilibrium is stressed, the equilibrium will move so as to offset the stress. Note that $\text{offset}$ does not mean $\text{counteract}$.

For a fuller treatment, consult a text.

Typically, we would use $\text{Le Chatelier's Principle}$ to manipulate an equilibrium, e.g.:

${N}_{2} \left(g\right) + 3 {H}_{2} \left(g\right) r i g h t \le f t h a r p \infty n s 2 N {H}_{3} \left(g\right)$

And this is probably the most important reaction on the planet. If we reduce the concentration of ammonia (by condensation for instance) we may drive the equilibrium to the right.