A drum contains $42$ gal of toluene. If the lid of the drum is left open $($lid diameter $=3$ ft$),$ determine the time required to evaporate all the toluene in the drum. The temperature is $85\backslash$deg F$.$ Estimate the concentration of toluene $($in ppm$)$ near the drum if the local ventilation rate is $1000$ ft$3/$min$.$ The pressure is $1$ atm.

Assume that the following equation can be used:

$C_{ppm}=\frac{Q_m{R}_{g}T}{k{Q}_{v}PM}$ x${10}^6$

Where

$C_{ppm}$ is concentration of volatile vapor in the enclosure $($mass$/$volume$),$

$Q_v$ is the ventilation rate $($volume$/$time$),$

$k$ is the nonideal mixing factor $($unitless$),$

$Q_m$ is the evolution rate of volatile material $($mass$/$time$),$

$R_g$ is the ideal gas constant,

$T$ is the absolute temperature,

$P$ is the absolute pressure, and

$M$ is the molecular weight of the volatile species.