The difference between the reaction enthalpy change $\left( \Delta_{r}H\right)$ and reaction internal energy change $\left( \Delta_{r}U\right)$ for die reaction :
$2C_{6}H_{6} \left(1\right) +15O_{2} \left(g\right) \to 12CO_{2} \left(g\right) + 6H_{2}O\left(1\right)$
at $300$ K is $\left(R=8.31 \,,mol^{-1}K^{-1}\right)$