Questions tagged [osmosis]
Osmosis the the movement of molecules through a permeable membrane barrier. It occurs as the molecules of a solvent stabilize the concentration of solute particles on either side of the barrier. Osmosis does not require input energy, it does deplete the kinetic energy of the solution.
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Help understanding osmotic pressure and van't Hoff equation
I am trying to understand how to interpret the van't Hoff equation for movement across a semi permeable membrane.
Let's say we have a concentration of 100 mM sucrose on the inside of a semi permeable ...
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Effects of an electrode in a microchannel flow
I am working on modeling the effects of an electrode in a microchannel flow. I am a little confused about how to model this.
I have two electrodes on the boundary. Do I add the electric field effects ...
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How to find the rate at which water can pass through a semipermeable membrane that allows particles of size lesser than 0.5 mm?
I was wondering what would be the rate at which water would cross a semipermeable membrane that allows particles of size greater than 0.5 mm. Knowing that size of water molecules is 2.75 angstroms ...
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Osmosis in a U-shaped tube with selective permeable membrane
Starting from the classical osmosis experiment, a U-shaped tube with a semi-permeable membrane, I would like to consider the case when the solute added to one of the compartments (labelled A) is ...
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The fundamental nature of osmotic pressure: electromagnetic?
As is known to all that osmotic pressure is an entropic force on a larger/statistical scale. But down to a smaller/microscopic sale, what's the origin or nature osmotic pressure? Is it electromagnetic ...
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Osmotic pressure "equilibrium"?
Consider a box with two compartments separated by a semipermeable membrane. The first compartment is initially at pressure $P_0$ and contains the solvent ; the second compartment is initially at ...
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Does osmotic pumping continue in plants at sub-zero temperatures?
Every now and again I stop and notice something which I find surprising, and try to work out why or how it happened. In this case I would like some assurance with the explanation.
We have a bucket ...
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Is osmosis stronger or weaker than gravity, and by how much?
Suppose you perpare a jar of salt water and another of sugar water and invert one on top of the other with a divider between them, and then carefully remove that divider so the liquids are in contact.
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What exactly is an entropic force?
In general the entropic force is defined as
$\vec{F}(\vec{X}_0) = T \vec{\nabla} S(\vec{X})\vert_{\vec{X}=\vec{X}_0}$,
where $T$ is the temperature of the system and $S(\vec{X})$ is the entropy ...
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Why does osmosis happen they way they do? [duplicate]
We know that in osmosis, the solvent molecules flow from the lower concentration to higher concentration across a semi-permeable membrane. But why do they flow like that?
For my explanation, I took ...
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How does the combination of freeze distillation and osmotic power respect the conservation of energy?
So imagine the following system.
You're in a cold part of the world. Sea water isn't isn't frozen over due to the ocean moderating temperature, but smaller lakes definitely have by now.
Sea water ...
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Why reverse osmosis does not cause perpetual motion?
In reverse osmosis, water molecules flow from dense solution to pure water under external pressure.
But how does this process prevents perpetual motion?
Consider the following example.
Salt water ...
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Where is the energy involved in osmosis?
Osmosis creates pressure on the side of the membrane with higher concentration. But where does the energy for this come from?
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By what mechanism is a growing tree root able to lift heavy concrete pavement?
A tree root lying under several square meters of 100mm thick concrete pavement can cause the pavement to lift up as it grows.
What forces are involved in creating this lift?
I vaguely understand that ...
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Why would tennis balls filled with sulfur hexafluoride explode?
An answer at Chemistry.SE tells the following anecdote:
Another fill gas to avoid is sulfur hexafluoride. A tennis ball manufacturer once decided to fill tennis balls with sulfur hexafluoride, ...
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