$3($c$)\_($#$)2$: A well$-$insulated rigid tank of volume $8\mathrm{.}25$ft$^(3)$ initially contains Nitrogen at $150\backslash$deg F and

$32$lb$($f$)/($i$)$n$^(2).$ A valve connected to the tank is opened and Nitrogen is withdrawn slowly until the

pressure within the tank falls to $19$lb$($f$)/($i$)$n$^(2).$ An electrical resistor inside the tank maintains the

temperature at $150\backslash$deg F throughout the process.

a