Imagine being able to use your computer to make phone calls with the help of special software and a microphoneâand bypassing your phone company and their charges.
So O2 has zero of heat of formation (or enthalpy of formation). The enthalpy of a reaction is defined like this: H = Hproducts-H reactants. The enthalpy of reaction in this case, is the same as the heat of combustion. Hproducts is obtained summing the heats of formation.
Well, I think you got tricked into thinking that you needed that equation to answer the question. What you really need is to look in the data book for the heat of combustion for which it will state it is -286kJ/mol. as, the energy density will be 143kJ/g.