Question

An insulated cylinder/piston contains carbon dioxide gas at 120 kPa, 400 K. The gas is compressed to 2.5 MPa in a reversible adiabatic process. Calculate the final temperature and the work per unit mass, assuming

a.  Variable specific heat, 

b.  Constant specific heat, value 

c.  Constant specific heat, value at an intermediate temperature

Answer 1

C.V. Air, a control mass undergoing a reversible, adiabatic process.

With two terms zero in the entropy equation we have a zero for the entropy change. So this is a constant s (isentropic) expansion process, s₂ = s₁.