1. The problem statement, all variables and given/known data NH3 + O2 --> NO + H2O Enthalpies of formation NO: 91.3 kJ H2O: -241.8 kJ NH3: -45.9 kJ 2. Relevant equations delta h = sum*moles enthalpy of formation of products - sum*moles enthalpy of formation of reactants 3. The attempt at a solution = [(1)(91.3) + (1)(-241.8)]-[(1)(-45.9)] = -104.kJ The answer in the back says -902 kJ. What am I missing?