An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide. 4NH3(g) + 5O2(g) --> 4NO(g) + 6H2O(g) Calculate DH°rxn for this reaction. DH°f [NH3(g)] = –45.9 kJ/mol; DH°f [NO(g)] = 90.3 kJ/mol; DH°f [H2O(g)] = –241.8 kJ/mol