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According to dictionaries, osmotic pressure is the pressure exerted by a dissolved substance in virtue to its molecular motion. But does the 'dissolved substance' mean the solute or the solvent? Does the pressure refer to the pressure exerted by the solute or the solvent molecules?

2007-07-13 22:12:27 · 5 answers · asked by Anonymous in Science & Mathematics Chemistry

5 answers

Osmotic pressure is the hydrostatic pressure produced by a solution in a space divided by a semipermeable membrane due to a differential in the concentrations of solute.

Osmotic potential is the opposite of water potential with the former meaning the degree to which a solvent (usually water) would want to stay in a liquid.

When a biological cell is in a hypotonic environment (the cell interior contains a lower concentration of water and a higher concentration of other molecules than its exterior), water flows across the cell membrane into the cell, causing it to expand due to osmotic pressure. In plant cells, the cell wall restricts the expansion, resulting in pressure on the cell wall from within called turgor pressure. The osmotic pressure π of a dilute solution can be calculated using the formula

π = iMRT,
where

i is the van 't Hoff factor
M is the molarity
R is the gas constant, where R = 0.08206 L · atm · mol-1 · K-1
T is the thermodynamic temperature (formerly called absolute temperature)
Note the similarity of the above formula to the ideal gas law and also that osmotic pressure is not dependent on particle charge.


[edit] Applications
Osmotic pressure is the basis of reverse osmosis, a process commonly used to purify water. The water to be purified is placed in a chamber and put under an amount of pressure greater than the osmotic pressure exerted by the water and the solutes dissolved in it. Part of the chamber opens to a differentially permeable membrane that lets water molecules through, but not the solute particles. The osmotic pressure of ocean water is about 27 atm. Reverse osmosis desalinators use pressures around 50 atm to produce fresh water from ocean salt water.

Osmotic pressure is necessary for many plant functions. It is the resulting turgor pressure on the cell wall that allows herbaceous plants to stand upright, and how plants regulate the aperture of their stomata. In animal cells which lack a cell wall however, excessive osmotic pressure can result in cytolysis.

Cell wall
Cytolysis
Gibbs-Donnan effect
Osmosis
Pfeffer cell
Plasmolysis
Potential osmotic pressure
Turgor pressure
For the calculation of molecular weight by using colligative properties, osmotic pressure is the most preferred property

2007-07-13 22:16:42 · answer #1 · answered by bhuvan 4 · 3 0

Osmotic Pressure

2016-10-07 02:30:58 · answer #2 · answered by vanderbilt 4 · 0 0

1

2016-12-23 00:55:16 · answer #3 · answered by Anonymous · 0 0

Osmotic pressure is the hydrostatic pressure produced by a solution in a space divided by a semipermeable membrane due to a differential in the concentrations of solute.

2007-07-13 22:37:07 · answer #4 · answered by Anonymous · 0 0

The phenomenon of the flow of solvent through a semipermeable membrane from the pure solvent to the solution (or from a more dilute solution to a less dilute one) when they are separated by that membrane, is defined as OSMOSIS.

thus if we place a sugar soln of higher concentration in an inverted thistle funnel whose mouth is closed with a semipermeable membrane & which is placed in contact with a soln of lesser concentration, solvent will flow into the thistle funnel and the level of soln in the funnel will rise.Such a flow of solvent across a semipermeable membrane will continue till the system comes to an equilibrium state, when the pressure exerted by column of soln of higher concentration becomes equal to the pressure exerted by the less concentrated soln across the membrane, which directs the flow of solent into the soln.This pressure, generated due to osmosis is called osmotic pressure.

2007-07-13 22:51:20 · answer #5 · answered by s0u1 reaver 5 · 0 0

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These are all colligative properties, which means they only depend on the number of particles in solution. Here we go: 1. Amazingly I couldn't remember this formula off the top of my head, but I've done some nice and quick Googling. The formula seems to be: V.P. = (Vapor Pressure of Pure)(Mole Fraction of Solute) the mole fraction of the solute is given by: Moles Solute / Moles Total (including the moles of solute) You should be able to solve that fine. (.39/(5.4+.39))*41 2. dT = kf * i * m Where dT is the change in freezing temperature, kf is the freezing point depression constant, m is molality (moles solute / kg solvent), and i is the Van't Hoff factor (the number of particles the solute in question breaks into. For instance: organic compounds are nonionic, and don't break down, so the value for i = 1. NaCl on the other hand breaks into 2 particles, i = 2) dT = ((5/MMC10...)/.444kg) * 1 * 4.90 3. pi = iMRT Where pi is the osmotic pressure, i is the Van't Hoff factor, R is the Ideal Gas constant .0821 L * atm / mol * K, T is the temperature is Kelvin, and M is the molarity (moles / L) pi / i * R * T = mol/L mol/L * L = mol g / MM = mol ---> g / mol = MM I hope this helps.

2016-03-27 02:14:01 · answer #6 · answered by Anonymous · 0 0

osmotic pressure is the pressure required to stop the passage of water completely and is represented by the greek letter psi . it is equivalent to the pressure which is applied externally in order to prevent the flow of solvent due to osmosis.
osmotic pressure is equivalent to the osmotic potential . osmotic pressure is positive where as osmotic potential is negetive

2014-02-12 15:06:02 · answer #7 · answered by Bhagya lakshmi 1 · 0 0

solute literally means dissolved substance...
Osmotic pressure is the pressure of the solute (dissolved substance) to go forth and expand equally to all parts of the medium (solvent).

2007-07-13 22:21:44 · answer #8 · answered by andychuck 2 · 2 0

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