1. A gas has the following initial properties, m = 25 lb, P1 =485.3 psig, and T1 = 545 R. A certain amount is vacuumed out of the tank causing the following changes in the properties, T2 = 70 deg F...

1. A gas has the following initial properties, m = 25 lb, P1 =485.3 psig, and T1 = 545 R. A certain amount is vacuumed out of the tank causing the following changes in the properties, T2 = 70 deg F and P2=285.3 psig. If heat was added to the remaining amount of gas in the tank causing an increase of temp of 85 deg F, prove that the following answers are achieved:
a. mass = 15.43 lbm;
b. weight = 15.43 lbf;
c. gage pressure is 316.36 psi if the tank is 17,280 in3
.
Note: Gas is unknown. Do not assume that the gas is air.