One mole of a real gas is subjected to a process from (2 bar, 30 lit, 300 K) to (2 bar, 50 lit, 400 K) Given : $C_v=40\mathrm{J}/\mathrm{mol}/\mathrm{K},C_p=50\mathrm{J}/\mathrm{mol}/\mathrm{K}$ Calculate $∆\mathrm{U}$