8. A piston-cylinder device contains 0.85 kg of refrigerant-134a at -10 °C. The piston that is

free to move has a mass of 12 kg and a diameter of 25 cm. the local atmospheric pressure

is 88 kPa. Now, heat is transferred to refrigerant-134a until the temperature is 15 °C.

Determine (a) the final pressure (b) the change in the volume of the cylinder and (c) the

change in the enthalpy of the refrigerant-134a.

R-134a

0.85 kg

-10°C