Problem $3.19\mathrm{.}3-5$ Diffusion of $N_2$ Through Two Membranes in Series. $(20$ pts$)$

Nitogen gas $($A$)$ at $2\mathrm{.}0$atm partial pressure and $30C$ is diffusing through a solid membrane of

nylon $1\mathrm{.}0mm$ thick and polyethylene $8\mathrm{.}0mm$ thick in series. The partial pressure of $N_2$ on the

other side of the two films is $0$atm. Calculate the diffusive flux of $N_2,N_A,$ at steady state.