3.2. Rate of Mass Transfer from Sediments

Try these first

1. 1.

   Define flux in the context of mass transfer.

   Hint

   Think about how we measure movement of pollutants.

2. 2.

   What does Fick’s law describe?

   Hint

   Recall how concentration affects movement.

3. 3.

   What is the main purpose of Fick's law?

   • To define mass density
   • To describe diffusion rates
   • To calculate pressure

   Hint

   Think about how concentration affects movement.

4. 4.

   True or False: Higher viscosity always leads to higher diffusion rates.

   • True
   • False

   Hint

   Consider how thickness affects motion.

5. 5.

   A river with a steady flow has pollutants entering from sediments. If the concentration gradient from the sediment to water is calculated to be 2 mg/L over a distance of 0.5m, calculate the flux using Fick's law where the diffusion coefficient is known to be 0.01 m²/s.

   Hint

   Remember to convert units if necessary!

6. 6.

   Explain how different velocities in a river would change the resistance to mass transfer. Illustrate with examples.

   Hint

   Use analogies from previous examples discussed in class!