(2a). Briefly describe the main features of ideal gas; (4 points) (2b). At temperature T, the specific enthalpy of N2 is 10000 kJ/kmol. Please find the temperature,specific internal energy, and

specific heat ratio of N2 at this temperature, (6 points) (2c) At temperature T, the specific heat of air under constant volume 0.80 kJ/kg. Find the specific heat under constant pressure and specific heat ratio of air. (6 points)