2- Calculate the internal energy and the enthalpy of 1 kg of air occupying 0.05 m3 at20 oC at 20 bar. If the internal energy is increased by 120 kJ as the air compressed to 50 bar. Calculate the new volume occupied by 1 kg of air. (250.1, 350.1 kJ/kg,0.0296m³) 3- Oxygen at 200 bar is to be stored in a vessel at 20.C. The capacity of the vessel is 0.04 m3. Assuming oxygen to be a perfect gas. Calculate the mass of the oxygen that can be stored in the vessel. The vessel is protected against excessive pressure by fusible plug which can be melt when the temperature limit the pressure vessel to 240 bar, find the temperature at which the plug melt. (10.2kg, 78.6°C)