Calculate the enthalpy change, ΔrH, for the following reaction,

Question

4 NH3 (g) + 5 O2(g) → 4 NO (g) + 6 H2O (g)

given the thermochemical equations below.

N2 (g) + O2 (g) → 2 NO (g) ΔrH° = +181 kJ
N2 (g) + 3 H2 (g) → 2 NH3 (g) ΔrH° = 91.8 kJ
2 H2 (g) + O2 (g) → 2 H2O (g) ΔrH° = 484 kJ