Q$6.$ A piston$-$cylinder device initially contains steam at $3\mathrm{.}5$ MPa $,$ superheated by $5C.$ Now, steam

loses heat to the surroundings and the piston moves down, hitting a set of stops, at which point the

cylinder contains saturated liquid water. The cooling continues until the cylinder contains water at

$200C.$ Determine $($a$)$ the initial temperature, $($b$)$ the enthalpy change per unit mass of the steam by

the time the piston first hits the stops, and $($c$)$ the final pressure and the quality $($if mixture$).$