Question

Please help with this question...cant figure it out.

Determine delta_r H^degree for the following reaction, 2 NH_3(g) + 5/2 O_2(g) rightarrow 2 NO(g) + 3H_2O(g) given the thermochemical equations below. N_2(g) + O_2(g) rightarrow 2 NO(g) n_2(g) + 3H_2(g) rightarrow 2 NH_3(g) 2 NH_2 O(g) 2 H_2(g) + O_2(g) rightarrow 2 H_2 O(g) delta_r H degree = + 180.8 Kj/mol-rxn delta_r H degree = -91.8 Kj/mol-rxn delta_rH degree = 483.6 kJ/mol-rxn -1178.2 kJ/mol -452.8 kJ/mol -394.6 kJ/mol-rxn -211.0 kJ/mol-rxn + 1178.2 kJ/mol-rxn