Be careful when you make up questions using average bond enthalpies to arrive at enthalpy changes for a reaction. Usually it will give results that are quite close to the literature values - but not always. Consider the case of using average bond enthalpies for determining the enthalpy of combustion of methane.CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)Using the values from Section 11 of the IB data booklet the energy that...