3.3. Interfacial Mass Transfer

Try these first

1. 1.

   What does Fick's Law of Diffusion describe?

   Hint

   Think about the direction of flow regarding concentration.

2. 2.

   Name one factor that affects mass transfer resistance.

   Hint

   Consider properties of the medium.

3. 3.

   What does Fick's Law of Diffusion indicate about substance movement?

   • It moves from low to high concentration
   • It moves from high to low concentration
   • It moves randomly

   Hint

   Remember the direction of concentration gradients.

4. 4.

   Does a higher molecular weight lead to higher mass transfer resistance?

   • True
   • False

   Hint

   Think about how size affects mobility.

5. 5.

   Calculate the rate of diffusion for a substance given its concentration gradient of 5 mol/m³ over a distance of 2 meters, using a diffusion coefficient of 0.1 m²/s.

   Hint

   Remember the negative sign indicates direction.

6. 6.

   A river has been found contaminated by a pollutant with mass transfer into water from sediment influenced by a concentration gradient of 3 mmol/L. If the sediment concentration is 12 mmol/L, how would you set up your mass balance equation?

   Hint

   Think what trends in concentrations might affect your calculations.