Question

Air initially at 0.1 MPa, 27 degC, is compressed reversibly to a final state. Assume air is an ideal gas with constant specific heats. (a) Find the entropy change of the air when the final state is 0.5 MPa, 227 degC.

Answer 1

The entropy change of the air when the final state is 0.5 MPa and 227°C is 0.051 kJ/kg K

Step-by-step explanation:

According the assumptions:

-air as ideal gas

-constant specific heats

The change of entropy is equal to:

`S_(2) -S_(1) =C_(p) ln((T_(2) )/(T_(1) ) )-Rln((P_(2) )/(P_(1) ) )\\S_(2) -S_(1)=1.005ln((227+273)/(27+273) )-0.287ln((0.5)/(0.1) )=0.051kJ/kgK`