5 moles of unknown gas is heated at constant volume from 10 °C to 20 °C. The molar specific heat of this gas at constant pressure c_p=8 cal / mol.^°…

$\displaystyle 5$ moles of unknown gas is heated at constant volume from $\displaystyle 10$ °C to $\displaystyle 20$ °C. The molar specific heat of this gas at constant pressure $\displaystyle c_p=8 \mathrm{cal} / \mathrm{mol} .{ }^{\circ} \mathrm{C}$ and $\displaystyle R=8.36 \mathrm{~J} / \mathrm{mol} .{ }^{\circ} \mathrm{C}$. The change in the internal energy of the gas is $\displaystyle \_\_\_\_$ calorie.