Question

A diffusion coefficient KG was determined for the diffusion of a gas A through a stagnant film B [KG = 0.88 mol//h-ft2-atm].

Answer 1

Explanation:

Transfer of mass A into stagnant film B depends on the availability of driving force.

Whereas driving force is the pressure difference at the surface of A and the bulk.

As,       $N_{A} \propto (P_{A1} - P_{A2})$

           $N_{A} = K_{G} \times (P_{A1} - P_{A2})$

Therefore, putting the given values into the above formula as follows.

         $N_{A} = K_{G} \times (P_{A1} - P_{A2})$

                     = $0.88 \times (0.2 atm - 0.05 atm)$

                     = 0.132 $mol/h.ft^{2}$

Thus, we can conclude that the flux of A from a surface into a mixture of A and B is 0.132 $mol/h.ft^{2}$