Hydrogen for an ammonia plant is made in three stages. stage 1 Methane reacts with steam: CH4(g) + H2O(g) -> CO(g) + 3H2(g) stage 2 CO(g) + H2O(g) <=> CO2(g) + H2(g) enthalpy change = -41 kJ mol-1 stage 3 The hydrogen is combined with nitrogen to make ammonia. Stage 2 is normally run with 1 mol of CO to 1 mol of H2O(g), at about 400 C, over a solid iron oxide catalyst.