Air passes steadily through a device from 20 psia and 80°F to 40 psia. During the process a work input of 24.2 Btu/lb is required, and a heat loss of 7.0 Btu/lb occurs with the energy appearing in the atmosphere at 80°F. Determine
(a) the entropy change of the air, and
(b) the entropy change of the atmosphere, both in Btu/(lb)(°R).
(c) Is the process reversible, irreversible, or impossible?