Osmotic Pressure

Information about Osmotic Pressure

Osmotic pressure on red blood cells

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

$\text{[math]}$ ,

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.

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.

For the calculation of molecular weight by using colligative properties, osmotic pressure is the most preferred property

External links

Fluid statics (also called hydrostatics) is the science of fluids at rest, and is a sub-field within fluid mechanics. The term usually refers to the mathematical treatment of the subject.
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Pressure (symbol: p) is the force per unit area applied on a surface in a direction perpendicular to that surface.

Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.
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semipermeable membrane, also termed a selectively permeable membrane, a partially permeable membrane or a differentially permeable membrane, is a membrane which will allow certain molecules or ions to pass through it by diffusion and occasionally specialized
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Water potential is the potential energy of water relative to pure water in reference conditions. It quantifies the tendency of water to move from one area to another due to osmosis, gravity, mechanical pressure, or capillary action.
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Biological tissue is a collection of interconnected cells that perform a similar function within an organism.

The study of tissue is known as histology, or, in connection with disease, histopathology.
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hypotonic solution has the lower osmotic pressure of two fluids and also describes a cell environment with a lower concentration of solutes than the cytoplasm of the cell. Given a cell placed in a hypotonic environment, osmosis causes a net flow of water into the cell, causing
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Water is a common chemical substance that is essential to all known forms of life.^[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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Plant cells are quite different from the cells of the other eukaryotic kingdoms' organisms. Their distinctive features include:

A large central vacuole (enclosed by a membrane, the tonoplast

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cell wall is a fairly rigid layer surrounding a cell, located external to the cell membrane, which provides the cell with structural support, protection, and acts as a filtering mechanism. The cell wall also prevents over-expansion when water enters the cell.
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In biology, turgor pressure or turgidity is the pressure of the cell contents against the cell wall, in plant cells, determined by the water content of the vacuole, resulting from osmotic pressure. i.e.
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In physical chemistry, the van 't Hoff factor is the number of moles of solute actually in solution per mole of solid solute added. Equivalently, refers to the ratio of true molecular mass to calculated molecular methods by colligative methods.
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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.
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Thermodynamic temperature is the absolute measure of temperature and is one of the principal parameters of thermodynamics. Thermodynamic temperature is an “absolute” scale because it is the measure of the fundamental property underlying temperature: its null
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The ideal gas law is the equation of state of a hypothetical ideal gas, first stated by Benoît Paul Émile Clapeyron in 1834.

The state of an amount of gas is determined by its pressure, volume, and temperature according to the equation:

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Reverse osmosis is a separation process that uses pressure to force a solvent through a membrane that retains the solute on one side and allows the pure solvent to pass to the other side.
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Standard atmosphere is a pressure defined as 101 325 Pa and used as unit of pressure (symbol: atm). Standard atmosphere is a non-SI unit that is internationally recognized.
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Desalination, desalinization, or desalinisation refer to any of several processes that remove excess salt and other minerals from water. Desalination may also refer to the removal of salts and minerals more generally,^[1] as in soil desalination,
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Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of ~3.5%, or 35 parts per thousand. This means that every 1 kg of seawater has approximately 35 grams of dissolved salts (mostly, but not entirely, the ions of sodium chloride: Na
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A herbaceous plant is a plant that has leaves and stems that die at the end of the growing season to the soil level. A herbaceous plant may be annual, biennial or perennial.

Herbaceous perennial plants have stems that die at the end of the growing season.
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stomata) is a tiny opening or pore, found mostly on the underside of a plant leaf, and used for gas exchange. The pore is formed by a pair of specialized sclerenchyma cells known as guard cells which are responsible for regulating the size of the opening.
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Cytolysis, or osmotic lysis, occurs when a cell bursts due to an osmotic imbalance that has caused excess water to move into the cell. It occurs in a hypotonic environment, where water diffuses into the cell and causes its volume to increase.
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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.
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Osmosis is the net movement of water across a partially permeable membrane from a region of high solvent potential to an area of low solvent potential, up a solute concentration gradient.
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Plasmolysis is an effect of osmosis in plants. Osmosis is the net diffusion of water across a selectively permeable membrane, such as a cell membrane, from an area of higher water concentration to an area of lower water concentration.
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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.
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