6. Mass-transfer problems can be solved by: a. Equilibrium Stage Calculations. b. The Concept of a diffusional process. c. a+b d. none of 7. Diffusion process can result from: a. molecular diffusion b. eddy diffusion c. a+b d. none of all. 8. Diffusivity depends on: a. type of solute b. type of solvent c. temperature and pressure d. all mentioned 9. Drifting Factor is: a. the ratio of partial pressure of species A to the logarithmic mean partial pressure of species B. b. the ratio of the total pressure to the logarithmic mean partial pressure of species B. the ratio of partial pressure of species A to the logarithmic mean partial pressure of species A. the ratio of the total pressure to the logarithmic mean partial pressure of species A. When the diffusion occurs through a varying cross-section area then: he flux is constant b. the rate is constant he flux is variable but the rate is constant d. the flux is constant but 1