$[10$ Pts$]$ A rigid container and a piston contains $1$ L of $R-134a$ at $100C$ and $3\mathrm{.}6$ MPa $.$ In an

isobaric quasi$-$equilibrium process, the gas expands to $1\mathrm{.}2$ L $.$ The control volume has a uniform

cross section $0\mathrm{.}5m^2$ and the piston can only move up and down. Ignore friction for simplicity.

$($a$)$ The critical temperature and pressure of R$-134$a are

$374\mathrm{.}2$ K and $4\mathrm{.}06$ MPa $,$ respectively. Is ideal gas law

reliable for this process? $[2$ Pts$]$

$($b$)$ What is the mass of R$-134$a in the system? $[5$ Pts$]$

$($c$)$ What is the working power during this expansion if

the piston is moving at a speed of $10c\frac{m}{s}?[3$ Pts$]$