Approximately $3/4$ of the volume of a sealed tank contains liquid heptane. The rest is air and heptane vapors. The

tank has been sitting at $72\mathrm{.}0$ oF for a long time. The pressure in the tank is $100\mathrm{.}7$ kPa.

$($a$)$ Calculate the partial pressure $($kPa$)$ and the mole fraction $($PPM$)$ of heptane vapors in the bulk air inside the tank.

$($b$)$ Compare this mole fraction to the OSHA PEL of this chemical. Would it be dangerous for a worker to enter this tank

and work inside it full time?

$($c$)$ Calculate the mass concentration of the heptane vapors in this bulk air in units of g$/$m