Table of Contents

• Developing the Equations
• 1: Review of diffusion equations
• 2: The two-compartment model
• 3: What does continuous mean?
• 4: Examples of permeability
• 5: A formula for permeability
• 6: The area of the membrane
• 7: The final equations
• Examples
• 8: Calculating molecular weight
• 9: Molarity of sugar-goo
• 10: Practicing conversions
• 11: Rate of flux
• 12: Review
• Discrete vs. Continuous
• 13: A metaphor
• 14: Continuous curves
• 15: Discrete curves
• 16: Iterating the discrete curve

And what you've all been waiting for

Here's another kind of possible problem: Using the equation governing the flow of sugar across a membrane from the following equation

And given that

P= 0.02 cm/sec

the area of the membrane between the two solutions is 2 cm²

Solution left side of the membrane = 0.4M

Solution right side of the membrane = 0.1M

What is the rate of diffusion across the membrane for the following concentrations? This kind of problem requires straightforward plug-and-chugging...

0.02cm/sec x 2 cm² x (0.4M sugar - 0.1M sugar)

= 0.012 moles/second

What would happen if we doubled the permeability constant?

What if we doubled the area of the membrane?

What if we doubled the concentration on the left?