2.2 g of nitrous oxide (N₂O) gas is cooled at a constant pressure of 1 atm from 310 K to 270 K causing the compression of the gas from 217.1 mL to 167.75 mL. The change in internal energy of the process, $\Delta$U is '$-$x' J. The value of 'x' is ________. [nearest integer]

(Given : atomic mass of N = 14 g mol^$-$1 and of O = 16 g mol^$-$1. Molar heat capacity of N₂O is 100 J K^$-$1 mol^$-$1)