The feed into a flash tank consists of $25$ mol$/$s n$-$pentane, $40$ mol$/$s cis$-2-$butene, and $35$ mol$/$s n$-$

butane.

$($a$)$ Calculate the dew and bubble point temperatures of a mixture with the given feed composition

at $200$ kPa.

$($b$)$ Find the recovery of n$-$butane when the pressure is $200$ kPa and temperature is $290$ K$.$

$($c$)$ If the flash tank operates at $100$ kPa, at what temperature could you recover $60\%$ cis$-2-$butene in

the vapor