Problem $1$

An open tank, $10$ ft in diameter and containing benzene at $25\backslash$deg C$,$ is exposed to air in such a

manner that the surface of the liquid is covered with a stagnant air film estimated to be $0\mathrm{.}2$ in

thick. If the total pressure is $1$ atm and the air temperature is $25"$C$,$ what loss of material in pounds

per day occurs from this tank? The specific gravity of benzene at $60\backslash$deg F is $0\mathrm{.}877.$ The concentration

of benzene at the outside of the film is so low that it may be neglected. For benzene, the vapor

pressure at $25\backslash$deg C is $100$ torr, and the diffusivity in air is $0\mathrm{.}08$ cm$2/$s$.$ Only consider the initial loss

rate $($neglecting the change of the air film thickness$).$