Oxygen gas at 3.0 atm and 30°C is diffusing through a membrane of Polyethylene 3.0 mm thick and Nylon 7.0 mm thick in series. The partial pressure at the other side of the
two films is 0.5 atm, assuming no other resistances, calculate the flux NA at steady state.

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?