$3-29$ A piston$-$cylinder device contains $0\mathrm{.}85$ kg of refrigerant $-134$ a at $-10C.$ The piston that is free to move has a mass of $12$ kg and a diameter of $25$ cm $.$ The local atmospheric pressure is $97\mathrm{.}6$ kPa $.$ Then, heat is transferred to refrigerant$-134$a until the temperature reaches $20C.$ Determine $($a$)$ the final pressure, $($b$)$ the change in the volume of the cylinder, and $($c$)$ the change in the enthalpy. Answer:

$($a$)100$ kPa $,($b$){0\mathrm{.}0}^{}22355m^3,($c$)20\mathrm{.}97$ kJ