Answer
$2.48$ $kJ$
Work Step by Step
If $H_m$ and $U_m$ are the molar enthalpy and the molar internal energy of a perfect gas, then the difference between $H_m$ and $U_m$ is given by
$H_m-U_m=RT$
Given, $T=298 K$
Therefore,
$H_m-U_m=8.3145\times 298$ $J$
or, $H_m-U_m=\frac{8.3145\times 727}{10^3}$ $kJ$
or, $H_m-U_m=2.48$ $kJ$
