Diffusion rate (moles/area*sec) =
(Concentration gradient)*(Diff. coefficient)
Shouldn't the concentration difference have units of mole/m^3 ? Or are you providing the value of
(Diff. coefficient)/(thickness) ?
Determine the number of moles of calcium ions that move through a 1 micrometer*1 micrometer cross sectional area of the membrane in 1 second
(Concentration gradient)*(Diff. coefficient)
Shouldn't the concentration difference have units of mole/m^3 ? Or are you providing the value of
(Diff. coefficient)/(thickness) ?
J = -D * dC/dx
Where:
J is the flux of ions (amount of ions crossing the membrane per unit time and area),
D is the diffusion coefficient,
dC/dx is the concentration gradient (change in concentration per unit distance).
In this case, we're given:
D = 300 micrometers^2/second
dC/dx = 400 mol/m^2
To apply Fick's law, we need to convert the units, so:
- Convert the diffusion coefficient from micrometers^2/second to meters^2/second:
1 micrometer = 10^-6 meters
(300 micrometers^2/second) * (1 * 10^-6 meters/micrometer)^2 = 3 * 10^-4 meters^2/second
- Convert the concentration gradient from mol/m^2 to mol/m^3:
1 m^2 = (1 meter * 1 meter) = 1 meter^2
1 mol/m^2 = 1 mol / (1 meter^2) = 1 mol/m^3
Now we have:
D = 3 * 10^-4 meters^2/second
dC/dx = 400 mol/m^3
Plug these values into Fick's law:
J = -(3 * 10^-4 meters^2/second) * (400 mol/m^3)
The result of this equation will give us the flux J, which represents the number of moles of calcium ions crossing the membrane per unit time and area.
So, in one second, the number of moles of calcium ions that move through a 1 micrometer * 1 micrometer cross-sectional area of the membrane can be calculated using the above equation.