The difference between deltaH and DELTAE for the reaction 2C6H6 (l) +15O2 - 12CO2 (g) + 6H2O (l) at 25*C in KJ is

Heat of reaction at constant pressure is ΔH and at constant volume is ΔU.

ΔH-ΔU=ΔngRT

The difference between heats of reaction at constant pressure and constant volume for the following reaction at 25 C in kJ.

2C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(l)

ΔH-ΔU=ΔngRT

Δng=12-15=-3

ΔngRT=(-3)*(8.314*10-3KJ/mol/K)*(298 K)=-7.43

Hence ΔH-ΔU = -7.4KJ/mole