Energy Changes Due to Pressure and Temperature Changes

1. a volume of 20 cu ft of air at pressure of 50 psig is heated and expanded to 30 cu ft and 40psig find the change in the energy of air in joules.
(A)35564 j
(B) 48219 j
(C)123378 j
(d)167278j


2>A quantity of gas equal to 35 cu ft is to be expanded adiabatically.It has specific heat at constant pressure of 0.532 and constant  volume of 0.408.what is the value of exponential power k?
(a)0.124
(b)0.217
(c) 0.94
(d)1.30