Ex: 11-9 Nitrogen at 10 MPa and 150 K flows steadily through a tube with a mass flow rate (m⋅) of 1 kg/s, receiving heat from the surroundings at 300 K. At the end of the tube it enters an expansion valve and leaves at 1 MPa and 125 K. Using the real gas model determine (a) the rate of heat transfer (Q⋅), and (b) entropy generation rate (S⋅gen,univ) in the thermodynamic universe. What-if Scenario: What would the answers be if (c) the ideal gas, or (d) the phase-change model were used instead?