4. Refrigerant-134a at 320 kPa and 40°C undergoes an isothermal process in a closed system until its quality is 45 percent. On a per-unit-mass basis, determine how much work and heat transfer are required.

Formaldehyde at 52.688 bar and 175.65 ℃ passes through a heater-expander and emerges at 39.516 bar and 420.45 ℃. There is no work into or out of the heater, but heat is supplied. Calculate the heat transfer into the heater-expander per mole of formaldehyde

The air at 20 ° C and 60% RH is heated using a heat exchanger to reach 70 ° C. Using a psychrometric chart, determine a. The amount of heat added per 1 m³ of initial air = (kJ). b. Condensation temperature = (° C)

2. A piston-cylinder device initially contains 0.8 kg of nitrogen gas at 160 kPa and 240 °C. The nitrogen gas is now expanded to a pressure of 100 kPa isothermally. Determine the work boundary during this process. 3. A frictionless piston-cylinder device contains 6 kg vapor at 600 kPa and 400 °C. When heat is transferred to the system, the vapor temperature is increasing up to 500 °C. Calculate the work net during this heat transfer process.