- #1
iScience
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osmotic pressure is the pressure difference between two solutions of different solute concentrations separated by a semi-permeable membrane.
my book says: "the osmotic presssure is exactly the same as the pressure of an ideal gas of the same concentration as the solute. in fact, it's tempting to think of the osmotic pressure as being exerted entirely by the solute, once we have balanced the pressure of the solvent on both sides. This interpretation is bad physics."
why is it incorrect to say that the osmotic pressure comes from the solute?? fundamentally, at the site of the SP membrane, the solvent can pass through and the solute cannot, and the osmotic pressure is essentially the difference in the partial pressures exerted by the solvent molecules on each side. This difference comes from the fact that not all of the molecules hitting the SP membrane are the solvent molecules, some of them are the solute molecules which cannot pass through. So I don't see how it's bad physics to say that the solute is what's exerting the osmotic pressure (the pressure difference)
Thanks
my book says: "the osmotic presssure is exactly the same as the pressure of an ideal gas of the same concentration as the solute. in fact, it's tempting to think of the osmotic pressure as being exerted entirely by the solute, once we have balanced the pressure of the solvent on both sides. This interpretation is bad physics."
why is it incorrect to say that the osmotic pressure comes from the solute?? fundamentally, at the site of the SP membrane, the solvent can pass through and the solute cannot, and the osmotic pressure is essentially the difference in the partial pressures exerted by the solvent molecules on each side. This difference comes from the fact that not all of the molecules hitting the SP membrane are the solvent molecules, some of them are the solute molecules which cannot pass through. So I don't see how it's bad physics to say that the solute is what's exerting the osmotic pressure (the pressure difference)
Thanks