Consider isentropic flow of an ideal gas with constant k through a converging nozzle from a large tank at 500 K, 8 bar. Using the results of Problem .83(a) (given below) with k at 500 K, evaluate the temperature, in K, and pressure, in bar, at the state where Mach number is unity for

(a) air.
(b) oxygen, O2
(c) carbon dioxide, CO2

Air inially occupying a volume of 1 m2 at 100 kpa, 27 c undergoes three internally reversible processes in series. process 1-2 compression to 500 kpa during which pv constant process 2-3 adiabatic expanslon to 100 kpa process 3-1: constant-pressure expansion to 100 kpa (a) calculate the change of entropy for each of the three processes. (b) calculate the heat and work involved in each process. (c) is this cycle a power cycle or refrigeration cycle?