Example: Calculate heat of formation of methane (CH4) : C(s)+2H2CH4(g)H=? In addition, we have the following data: 1. CH4(g)+2O2(g)CO2(g)+2H2O(g)cH= 802.37kJ/mol 2. CO2(g)C(s)+O2(g)H=39.50 kJ/mol 3. H2(g)+1/2O2(g)H2O(g)H= 241.83kJ/mol