Carbon dioxide flows steadily through a variable-area duct with a mass flow rate of 2 kg/s. It

Question:

Carbon dioxide flows steadily through a variable-area duct with a mass flow rate of 2 kg/s. It enters the duct at 1400 kPa and 250oC with negligible velocity and expands to a pressure of 200 kPa is entropically. Determine
The exit Mach number,
Flow area and
The critical flow area.