1.5. Molecular Diffusion

Try these first

1. 1.

   What is molecular diffusion?

   Hint

   Think about how a drop of ink spreads in water.

2. 2.

   What does the diffusion coefficient indicate?

   Hint

   Consider what affects how fast something can move in a fluid.

3. 3.

   What is the primary driver of molecular diffusion?

   • Temperature
   • Chemical potential
   • Pressure

   Hint

   Consider what initiates movement in a substance.

4. 4.

   True or False: Diffusion cannot occur without bulk movement.

   • True
   • False

   Hint

   Think about what happens in a stagnant liquid.

5. 5.

   Calculate the expected concentration of a pollutant within a river if an initial concentration of 5 mg/L is released and it diffuses evenly at a rate defined by its diffusion coefficient across a width of 2 m over a distance of 100 m.

   Hint

   Feel free to reference concentration gradient equations.

6. 6.

   A tank holds 100L of water with a chemical concentration of 10mg/L. If a 1 g chemical is added, how will diffusion alter concentration over time, considering the diffusion coefficient?

   Hint

   Examine how the diffusion coefficient impacts equilibrium state.