Chemical potential vs hydro-static pressure during osmosis

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Osmosis involves the movement of solvent from an area of higher chemical potential to one of lower potential across a semipermeable membrane, leading to fluid level differences. This process raises questions about its compatibility with hydrostatic laws, particularly whether chemical potential can overcome hydrostatic forces. In a U-tube manometer setup with a semipermeable membrane, the chemical potential of the solvent is influenced by solute concentration and pressure. At equilibrium, the chemical potential must equalize on both sides, necessitating different pressures due to varying solute concentrations. Ultimately, the balance between gravitational potential energy and chemical potential energy is established when equilibrium is reached.
Urmi Roy
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So when osmosis between two solutions (separated by a semipermeable membrane),takes place, the solvent travels from the side where its chemical potential is higher to the side where its chemical potential is lower.
However, this results in a difference of levels of fluids across the membrane.

Doesn't this contradict the laws of hydro-statics? Is chemical potential enough of a driving force to overcome hydro-static forces?

Thanks a lot!
 
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Can you describe the setup of the system you are interested in? Typically one is interested in systems where the exchange takes place only through the membranes.
 
Yeah, I'm just considering a system in which a structure that looks like a u-tube manometer, but with a semipermeable membrane at the bottom of the 'U' shape, which separates 2 solutions and supposed the one on the left is more concentrated. The exchange does take place only via the membrane.
 
Yes, the forces are quite large. The chemical potential of the solvent depends on both the concentration of the solute and the pressure. In equilibrium, the chemical potential of the solvent has to be equal on both sides, hence for different concentrations of the solute, pressure has to be different, too.
 
DrDu said:
Yes, the forces are quite large. The chemical potential of the solvent depends on both the concentration of the solute and the pressure. In equilibrium, the chemical potential of the solvent has to be equal on both sides, hence for different concentrations of the solute, pressure has to be different, too.

The hydro-static forces are basically due to the weight of fluid column, so when chemical equilibrium is established, is it like the gravitational potential energy is just balanced by the chemical potential energy?
 
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