the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides.

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How is Gibbs-Donnan equation derived?

Could it be derived from fundamental relations of gibbsian thermodynamics and other relevant physics? Or is the equation solely representing an experimental fact that only approximates the more ...
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In osmosis why does the solvent move from pure solvent to the solution?

In osmosis, a substanec moves from region of low to high concentration. So why is it that solvents move from the region of pure solvent into the region of solution? Doesn't the pure solvent have the ...
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Does Reverse Osmosis remove elemental ions from water?

From what I understand, RO is able to remove (or at least considerably reduce) the salts dissolved in water. But thinking about it just doesn't make sense. RO works by filtering the solution using a ...
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58 views

Osmotic Pressure

If the osmotic pressure of a 0.010 M aqueous solution of sucrose at 27˚C is 0.25 atmosphere, then the osmotic pressure of a 0.010 M aqueous solution of NaCl at 27˚C is (a) 0.062 atm (b) 0.12 atm ...
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What's the difference between reverse osmosis and ultrafiltration?

I was recently reading about ultrafiltration in blood capillaries. In such a case, as I understood, tissue fluid moves from capillaries to tissues against the concentration gradient due to the high ...
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90 views

Can I equalise osmotic pressure using two different solutes?

I understand that there is a pressure gradient between an aqueous solution, e.g. salty water, and, say, pure water due to osmosis. My question is, is it possible to match or almost match, the osmotic ...
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101 views

Fundamental physical forces behind osmosis

I wonder which fundamental forces act behind osmosis process? Sum of these forces oppose gravity force, like in this figure: So I wonder what are these forces?
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176 views

Highest osmotic pressure

I’d like to ask a question and clear my misunderstanding. Which of the following 0.01 M solutions have the highest osmotic pressure? -$\ce{NaCl}$ -$\ce{C12H22O11}$ -$\ce{BaCl2}$ ...
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39 views

Water softener and RO filter

I have a water softener for showers and dishwasher and a reverse osmosis filter for drinking water. For convenience of the install, the RO filter is using softened water (some calcium carbonate has ...
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190 views

Why is pickle salty? How does salt get into pickle?

I know this may look like some question easily answered with common sense, but please read. If water is the solvent wouldn't the only thing that moves be water? (Osmosis) Edit: this is basically ...
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349 views

How to calculate the osmotic pressure of a sucrose solution?

The boiling point of an aqueous solution containing sucrose, $\ce{C12H22O11}$, is $101.45~^\circ\mathrm{C}$. Calculate the osmotic pressure of this solution at $35~^\circ\mathrm{C}$, at which the ...
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516 views

Converting mm Hg to mm H2O

So here's my problem : What is the osmotic pressure, noted in mm of H2O, of a solution with 125 micrograms of vitamin B12 (C63H88CoN14O14P) in 2.50 mL of H2O at 25 degree celsius. The "hint" that ...
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143 views

How to create a simple do-it-yourself procedure to measure diffusion?

While I am not asking the question here, a recent question concerning osmosis at the Bio SE caught my interest. In a nutshell that question was, given isotonic solutions of sugar inside and outside an ...
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260 views

Why is dialysis tubing impermeable to sucrose?

This question was posed a couple years ago but not answered adequately. You can view the older thread here. The cellulose membrane commonly used in high school and university labs is widely available ...
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Use of osmosis to measure molecular weight of macromolecules

How can osmosis be used to measure molecular weight of macromolecules ? Is it applied practically ?
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663 views

colloidal osmotic pressure?

The oncotic pressure or colloidal osmotic pressure is the osmotic pressure developed due to the presence of colloids in a solution. But since the colloids are not true solution, why should the ...
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167 views

How might one reduce the concentration of bubbles in their ice, from ice cube trays?

So I have been freezing ice a lot recently, and I will come out and say it, as it turns out it is, albeit unlikely, it is sometimes possible for ice to "explode." I was not so aware of this before, ...
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Why is dialysis tubing impermeable to sucrose when it should retain >12,000 Da?

While writing up a lab for biology, I realized that the dialysis tubing for sale online seemed to retain large molecules (12-14,000 Da) but didn't specify an upper bound. I learned that the tubing is ...