Why does the Haber process take place at high temperature and pressure?

Reaction : N2 + 3H2---> 2NH3 is in equilibrium The reaction is exothermic (produces heat) so the equilibrium will favor the left at high temperatures following Le Chatelier's principle. This is to reduce the amount of heat produced by the reaction in order to maintain the position of equilibrium. A compromise temperature of around 450 degrees is used to increase the rate of reaction. 2 moles of gas (right hand side) are produced from 4 moles of gas (left hand side) so high pressures will shift the equilibrium to the right in order to reduce the number of moles in the reaction mixture and hence decrease the pressure. A pressure of 200 atmospheres is used to increase the pressure without forming potentially dangerous and expensive conditions. An Fe catalyst is also used. This increases the rate of both the forwards and backwards reaction but has no effect on the position of equilibrium.