A2 Q1:

Refrigerant 134A is held in aa large storage tank at 100 lbf/in^2, 50 F, A technicical refills a 3.5 ft^3 cylinder to take on a service call. Initially, the cylinder contains 5 lb of refrigerant at 70 F. The technician opens a valve and lets refrigerant flow into the cylinder until the amount of refrigerant in the cylinder is 30 lb and sets the sylinder in the service van. After a while, the temperature in the cylinder is 70 F again. Neglecting kinetic and potential energy effects, determinte the amount of energy transfered by heat in Btu.