Give the approximate temperature and pressure used in the reactor.

The Haber process conditions are a compromise between reaction rate, equilibrium yield, and cost. - **Temperature: 450 °C.** The forward reaction (N₂ + 3H₂ ⇌ 2NH₃) is exothermic. According to Le Chatelier's principle, a low temperature would favour a high yield of ammonia. However, a low temperature would also mean a very slow rate of reaction. A high temperature increases the rate but lowers the yield. 450 °C is a compromise temperature that gives a reasonable rate and a manageable yield, especially when used with an iron catalyst. - **Pressure: 200 atmospheres (atm).** The forward reaction involves a decrease in the number of moles of gas (from 4 moles of reactants to 2 moles of product). According to Le Chatelier's principle, a high pressure would favour a high yield of ammonia. However, building and maintaining very high-pressure equipment is expensive and dangerous. 200 atm is a compromise pressure that gives a good yield without being excessively costly.