Le Chateliers Principle

Le Chatiliers Principle states that for an equilbrium reaction the equilbrium will work in the opposite direct to the conditions forced on it.

This means that in reactions that are in equilibrium the can only reach a balance and when the conditions are changed the reaction can either produce more products or more reactants. In this case the reactants are Nitrogen and Hydrogen and the product is Ammonia. What we need to do is find the best conditions that will make the most ammonia.

The Haber Process Chemical Equation

looking at the above equation we can make the table below.

Condition Change	Tempurature Increase	Tempurature Decrease	Pressure Increase	Pressure Decrease
More or Less Ammonia	Less Ammonia	More Ammonia	More Ammonia	Less Ammonia

The reasons for this are simple:

The Haber Process is an exothermic reaction so it gives of heat. To add more heat would make the equilibrium create more of the reactants as the reverse process takes in heat.

In Equilibrium reactions the pressure is created by calculating the total number of moles of gas on each side of the equilibrium sign. In this case there is less pressure on the Ammonia side so increasing the pressure the reaction will try to reduce pressure so more ammonia is produced.

Please note that catalysts do not affect the equilibrium they just speed up the rate of reaction.

Return to the last page.

Author: David Hindle Last Modified 9th December Source: Shriver and Atkins, Inorganic Chemistry, 278