Nitrogen undergoes a process from state 1 at 220 K and 2 MPa to state 2 at

Question:

Nitrogen undergoes a process from state 1 at 220 K and 2 MPa to state 2 at 280 K and 20 MPa. Estimate the change in enthalpy and entropy:
i) Assuming the nitrogen is an ideal gas with constant specific heats from Table B-2
ii) Assuming the nitrogen is an ideal gas with constant specific heats interpolated from Table B-6 at 250 K
iii) Using the ideal-gas tables in the Appendix
iv) Using the equations of Section 7.5