What is Le Chatelier's principle for systems in equilibrium?
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.
To put this another way if an equilibrium is stressed, the equilibrium will move so as to offset the stress. Note that
For a fuller treatment, consult a text.
Typically, we would use
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.