10 mole of oxygen is heated at constant volume from 30 °C to 40 °C. The change in the internal energy of the gas is ____ cal. (The molecular specific…

$\displaystyle 10$ mole of oxygen is heated at constant volume from $\displaystyle 30$ °C to $\displaystyle 40$ °C. The change in the internal energy of the gas is $\displaystyle \_\_\_\_$ cal. (The molecular specific heat of oxygen at constant pressure, $\displaystyle C_p=7 \mathrm{cal} / \mathrm{mol} .{ }^{\circ} \mathrm{C}$ and $\displaystyle \mathrm{R}=2 \mathrm{cal} . / \mathrm{mol} .{ }^{\circ} \mathrm{C}$.)