pls help me

3. A rigid vessel contains 2kg of refrigerant- 134a at 800kPa and 120C. Determine the volume of the vessel and the total internal energy. 4. Determine the specific volume of nitrogen gas at 10MPa and 150K based on (a) the ideal-gas equation and (b) the generalized compressibility chart. Compare these results with the experimental value of 0.002388m3/kg, and determine the error involved in each case. 5. A 3.27-m m3 tank contains 100kg of nitrogen at 175K. Determine the pressure in the tank, using (a) the ideal-gas equation, (b) the van der Waals equation