A vertical piston$$cylinder device initially contains

$0\mathrm{.}2$ m$3$ of air at $20$C$.$ The mass of the piston is such that it main$-$

tains a constant pressure of $300$ kPa inside. Now a valve con$-$

nected to the cylinder is opened, and air is allowed to escape until

the volume inside the cylinder is decreased by one$-$half. Heat

transfer takes place during the process so that the temperature

of the air in the cylinder remains constant. Determine $($a$)$ the

amount of air that has left the cylinder and $($b$)$ the amount of heat

transfer