6.4 Isentropic Compression of Ammonia Superheated ammonia (NH3) vapor at 2 MPa, 80C expands in an adiabatic reversible process (isentropic, i.e., constant entropy), the temperature after expansion is measured as -25C. For both states, list pressure, temperature, specific volume, internal energy, enthalpy and entropy. Determine heat and work. Use the tables on pages 29-32 of our booklet.