benzene, energy released when burned?

Question

energy released when burned 1 mol of benzene is burned

Answer 1

C6H6 + 15/2 O2 ----> 6CO2 + 3H2O
-3 * 463 * 2(O-H) - 6 * 707 * 2(C=O) + 15/2 * 494(O=O) + 6 * 414(C-H) + 3 * 347(C-C) + 3 * 619 (C=C) = -2175KJ/mol

Edit:
I used bond energies in my answer, that are average and not same in all molecules and another thing is, because of using bond energies, H2O supposed to be a gas that it’s may wrong.
So it’s better to use enthalpy of formation.
(Supposed that T is constant and equal to 298.15k)
6mol * -393.509kj/mol (CO2) + 3mol * -285.830kj/mol (H2O) – 1mol * 82.93kj/mol (C6H6) = -3301.47kj
If T isn’t constant you can calculate enthalpy from this formula:
dH(T2) = dH(T1) + integral of ( delta Cp(for 1 mol) * dT)
That delta Cp(for 1 mol) is the difference of heat capacity in constant pursuer between T1 and T2 between products and reactants. [(Cp products in T2 - Cp products in T1) - (Cp reactants in T2 - Cp reactants in T1)]

Answer 2

You could always look up the enthalpy of combustion of benzene...

Answer 3

40.170 MJ/kg
=40.170*10^3 kJ/(1/0.078)mol
=3133.26 kJ/mol