2. Key Concepts

Try these first

1. 1.

   What is Fick's Law of Diffusion?

   Hint

   Think about how a perfume spreads in a room.

2. 2.

   Name one factor that increases the diffusion coefficient.

   Hint

   Consider the effect of heat on movement.

3. 3.

   What does Fick's law indicate?

   • Diffusion happens at constant rate
   • Substances move from lower to higher concentration
   • Substances move from higher to lower concentration

   Hint

   Consider how fragrances spread.

4. 4.

   True or False: An increase in temperature decreases diffusion.

   • True
   • False

   Hint

   Think of how heating something speeds it up.

5. 5.

   Calculate the expected flux of a pollutant in water if its concentration gradient between the sediment and water is known, considering a diffusion coefficient of 0.1 m²/s.

   Hint

   Remember that the negative sign indicates direction; focus on the concentration gradient.

6. 6.

   Assess how changing the density of water from 1g/cm³ to 0.5g/cm³ would impact the diffusion rate of a pollutant.

   Hint

   Compare the movement of a ping pong versus a bowling ball in water.