Directions: Work all three (3) problems. The exam is open notes and open text book. All problems have equal weight.

PROBLEM 1

Water at 40 kPa and 70°C goes through an isentropic compression which raises its pressure to 3 MPa. Then at constant pressure it is superheated 200°C. Determine the enthalpy change for each of the two processes.

PROBLEM 2

A closed, rigid 0.2 cubic meter tank contains 0.25 kg of carbon dioxide at a pressure of 50 kPa. Determine the change in internal energy and entropy if the pressure increases to 250 kPa.

PROBLEM 3

Water at 0.5 MPa and 250 C is contained in a cylinder-piston configuration. If the water is expanded in an isentropic process to 0.1 MPa, determine the change in internal energy.