Mass transfer. Solve the problem with the data, please

Local coefficients and average coefficients. There is a small cylindrical bed of 60 cm long, packed with naphthalene spheres (A) of 0.2 cm in diameter, as illustrated in Figure . The specific bed area of the packed spheres is approximately of 25 cm² for each cm³ of bed volume and is represented by a. To this bed feeds air (B) pure and dry at 1 atm and 75 C, at a superficial speed of 2 m/s. steam pressure of naphthalene at air temperature is 5 mm Hg. The mass transfer coefficient average in the bed is 6.81x10^-2 cm/s. It can be assumed that the naphthalene spheres do not change its size.

Calculate the molar flux of naphthalene at the outlet of the bed. Hint: First, define the difference of concentration to be used with the given average mass transfer coefficient as data. Then, calculate the average concentration at the outlet of the bed. Finally, calculate the molar flux of naphthalene at the outlet of the bed

= diy air CA = 0 T = 75 C P=1 atm Naz 2+A 60 cm E A Nai only the unshaded area is available to the stream air + naphthalene