Problem #$1$

A common gas undergoes equimolar counter$-$diffusion through a uniform tube $1\mathrm{.}55$ meters in length. The tube contains air at $101\mathrm{.}325$kPa and $298K.$ At one point, the partial pressure of the gas is $99\mathrm{.}78$KPa and at another point $49\mathrm{.}73$kPa. The diffusivity is given as $0\mathrm{.}175{10}^{-4}\frac{m^2}{s}.$ Calculate the flux for both the gas and air.