2 . 2g of nitrous oxide ( N _ 2 O) gas is cooled at a constant...

$2 . 2g$ of nitrous oxide $\left({N}_{2}O\right)$ gas is cooled at a constant pressure of $1$ atm from $310K to 270K$ causing the compression of the gas from $217 . 1mL to 167 . 75mL$. The change in internal energy of the process, $△ U$ is $' - x ' J$. The value of $' x '$ is _____.

[nearest integer]

(Given: atomic mass of $N = 14g{mol}^{- 1}$ and of $O = 16g{mol}^{- 1}$. Molar heat capacity of ${N}_{2}O$ is $100{JK}^{- 1}{mol}^{- 1}$)