haber process

[mc-ducky]

which factors affect a reversible reaction, such as a haber process?

[Docsteve]

There are three factors namely pressure, temperature and concentration linked to the use of catalysts: The three factors affect the equilibrium. The catalysts affects the speed of reaction. All of these impact according to Le Chatelier's principle in that if you act on a reaction the reaction will act to oppose it. (The energetics are simply reorganising in a non-anthropogenic way but the opposing idea is an easy way to think about it).

Consider the Haber Process

N2 + 3H2 > 2NH3

There are more molecules on the left (reactants). If you increase the pressure the system will act to oppose it by making products - fewer molecules less pressure. So the chemists take this up to 200atm (until the insurers and the chemists say that's enough).
The Haber process is exothermic (gives out heat). In theory this means you should cool it to get it to work. However, things would work very slowly so heat is required in a compromise situation. A catalyst is added to speed this up. So hot iron at 450degC is used.
Finally, if you can remove the product the reaction will aim to make more to keep the equlibrium. In the Haber Process, the product is removed by liquefaction (cooling) of ammonia and then the unused nitrogen and hydrogen are recycled.
Throughout the whole process new reactants are added to increase their concentrations. This also forces more products to be made to maintain the equilibrium.