Question

How to calculate enthalpy of formation using hess's law?

Answer 1

Standard Enthalpies of Formation. C(s)+O2(g)→CO2(g)ΔHf=−394kJ. Let's use these enthalpies of formation to calculate the enthalpy of combustion for 1 mol of methane. The reaction we want is. CH4(g)+2O2(g)→CO2(g)+2H2O(g) H2O(l)→H2O(g)ΔH=44kJ.