6.78 a two-phase liquid–vapor mixture of refrigerant 134a is held in a large storage tank at 100 lbf/in.2, 50°f, as illustrated in fig. p6.78. a technician fills a 3.5-ft3 cylinder that is initially evacuated to take on a service call. the technician opens a valve and lets refrigerant from the storage tank flow into the cylinder until the pressure gage on the cylinder reads 25.5 lbf/in.2 (gage). the surrounding atmospheric pressure is 14.5 lbf/in.2 assuming no heat transfer and neglecting kinetic and potential energy effects, determine the final mass of refrigerant in the cylinder, in lb, and the amount of entropy produced, in btu/°r.