Carbon dioxide is diffusing through nitrogen in one direction at atmospheric pressure and $0C.$ The mole fraction of $C{O}_2$ at point $A$ is $0\mathrm{.}2$ ; at point $B,3m$ away, in the direction of diffusion, it is $0\mathrm{.}02.$ The concentration gradient is constant over this distance. Diffusivity of $C{O}_2$ in $N_2$ under the given conditions is $0\mathrm{.}144c\frac{m^2}{s}.$ The gas phase as a whole is stationary; i$.$e$.,N_2$ is diffusing at the same rate as the $C{O}_2,$ but in the opposite direction.

a$)$ What is the molal flux of $C{O}_2$ in kgmole$\frac{s}{m^2}.$ h$?$

b$)$ What is the net mass flux in $k\frac{g}{m^2}.h?$