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. Fluid statics (also called hydrostatics) is the science of fluids at rest, and is a sub-field within fluid mechanics. ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin, Canberra. ... Scheme of semipermeable membrane during hemodialysis, where red is blood, blue is the dialysing fluid, and yellow is the membrane. ...

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. Water potential of negative water solution Water potential is the tendency of water to move from one place to another. ...

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 Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ... This article or section does not cite its references or sources. ... Impact of a drop of water. ... The cell membrane (also called the plasma membrane or plasmalemma) is a semipermeable lipid bilayer common to all living cells. ... Plant cell structure Plant cells are quite different from the cells of the other eukaryotic kingdoms organisms. ... A cell wall is a fairly rigid layer surrounding a cell, located external to the cell membrane, that provides the cell with structural support, protection, and a filtering mechanism. ... This article or section does not cite its references or sources. ...

π = iMRT,

where

i is the van 't Hoff factor

M is the molality

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. In physical chemistry, the Vant Hoft factor i is the number of moles of solute actually in a solution in water, per mole of solid solute added. ... This page refers to concentration in the chemical sense. ... The gas constant (also known as the universal or ideal gas constant, usually denoted by symbol R) is a physical constant used in equations of state to relate various groups of state functions to one another. ... Absolute zero is the lowest temperature that can be obtained in any macroscopic system. ... Isotherms of an ideal gas The ideal gas law is the equation of state of a hypothetical ideal gas, first stated by Benoît Paul Émile Clapeyron in 1834. ...

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. Reverse osmosis is the process of pushing a solution through a filter that traps the solute on one side and allows the pure solvent to be obtained from the other side. ... Standard atmosphere (symbol: atm) is a unit of pressure. ... Shevchenko BN350 desalination unit situated on the shore of the Caspian Sea. ... Annual mean sea surface temperature for the World Ocean. ...

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. This is not about surgically created bowel openings; see stoma (medicine) In botany, a stoma (also stomate; plural stomata) is a tiny opening or pore, found mostly on the undersurface of a plant leaf, and used for gas exchange. ... Cytolysis is the lysis, or death, of cells due to the rupture of the cell membrane. ...

See also

• Cell wall
• Cytolysis
• Gibbs-Donnan effect
• Osmosis
• Pfeffer cell
• Plasmolysis
• Potential osmotic pressure
• Turgor pressure

A cell wall is a fairly rigid layer surrounding a cell, located external to the cell membrane, that provides the cell with structural support, protection, and a filtering mechanism. ... Cytolysis is the lysis, or death, of cells due to the rupture of the cell membrane. ... The Gibbs-Donnan effect (also known as the Donnan effect, Donnan law, or Gibbs-Donnan equilibrium) is a name for the behavior of charged particles near a semi-permeable membrane to sometimes fail to distribute evenly on either side of the membrane. ... Osmosis is the net movement of water molecules across a semipermeable membrane from a region of low solute potential to an area of high solute potential (or equivalently, from a region of high solvent potential to a region of low solvent potential). ... Before Plasmolysis. ... Potential osmotic pressure (POP) is the maximum osmotic pressure that could develop in a solution if it were separated from distilled water by a selectively permeable membrane. ... This article or section does not cite its references or sources. ...

External links

• Osmotic pressure and potential
• Osmotic pressure
• Equations for osmotic pressure