Chapter 5 Principles of Chemical Reactivity: Energy and Chemical Reactions - Study Questions - Page 217f: 86

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Enthalpies of formation (kJ/mol): $H_2O(g):-241.83, CO_2(g):-393.509$ Hydrazine: $(2\times-241.83-50.6)\div 32.05\ g/mol=-16.66\ kJ/mol$ Dimethyl hydrazine: $(2\times-393.509+4\times-241.83-48.9)\div 60.10\ g/mol=-30.00\ kJ/mol$ 1,1-dimethylhydrazine produces more energy per unit of mass in combustion.