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Topic: Osmotic pressure


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In the News (Mon 24 Jun 19)

  
  Units: O
Solutions with higher concentrations of dissolved substances are said to have higher osmotic pressure than solutions having lower concentrations; thus the solvent moves from an area of low osmotic pressure to an area of higher osmotic pressure.
One osmole is the osmotic pressure of a one molar solution (that is, a solution with a concentration of one mole per liter of solvent) of a substance that does not dissociate, such as sugar (glucose) in water.
Osmotic pressure depends on the total number of dissolved particles, so for a substance that dissociates into two ions, such as ordinary salt (sodium chloride), a one molar solution has an osmotic pressure of 2 osmoles.
www.unc.edu /~rowlett/units/dictO.html   (2960 words)

  
  NationMaster - Encyclopedia: Osmotic pressure   (Site not responding. Last check: )
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.
The osmotic pressure obeys a law similar in form to that of the ideal gas law, PiV = nRT, where Pi is the osmotic pressure, V is the volume of the solution, n is the number of moles of solute, R is the ideal gas constant, and T is the absolute temperature.
Osmotic pressure or Osmotic potential is the hydrostatic pressure produced by a solution in a space divided by a differentially permeable membrane due to a differential in the concentrations of solute.
www.nationmaster.com /encyclopedia/Osmotic-pressure   (1236 words)

  
 Reference.com/Encyclopedia/Osmosis
Osmotic pressure is a colligative property, meaning that the property depends on the molar concentration of the solute but not on its identity.
The turgor pressure of a cell is largely maintained by osmosis, across the cell membrane, between the cell interior and its relatively hypotonic environment.
Osmotic pressure is a colligative property, meaning that the property depends on the concentration of the solute but not on its identity.
www.reference.com /browse/wiki/Osmotic   (1435 words)

  
 Osmotic pressure sensing head - Patent 4028931
An osmotic sensing head for measuring the osmotic pressure of protein molecules in blood, which is of the type that includes a reference chamber for holding saline solution, a sample chamber for holding blood, an osmotic membrane between the chambers, and a pressure sensor coupled to the reference chamber to measure the pressure therein.
The transducer 20 measures the hydrostatic pressure of fluid in the chamber 28, and the measured pressure is indicated by the pressure indicator 18 which is coupled to the transducer 20.
Inasmuch as the magnitude of the pressure reduction is due to the concentration of protein molecules in the blood sample which is contained in the sample chamber 24, the pressure is a direct indication of the concentration of blood protein molecules in the blood sample.
www.freepatentsonline.com /4028931.html   (2515 words)

  
 Method for measuring changes in osmotic pressure - Patent 6267003
The vapor pressure osmometer, boiling point elevation, freezing point depression, and isopiestic methods measure the oncotic pressure (the osmotic pressure exerted by colloid in the solution) of the solution, that is, the osmolality of the solution including the contribution of low molecular weight components such as salts.
By systematically varying the applied air pressure until the visually observed liquid meniscus of the dialyzate in the dialyzate tube is stationary, the osmotic pressure of the solution across the dialysis membrane is exactly balanced by the imposed air pressure.
Preferably, the osmotic pressure measured is then corrected for the slight hydrostatic pressure difference calculated from the difference in height of the liquid column in the dialyzate exit tube 58, and the height of the sample surface 64 in the sample cell 12 (typically this correction is between 1 and 10 centimeters of water).
www.freepatentsonline.com /6267003.html   (6852 words)

  
 Osmotic pressure - Encyclopedia, History, Geography and Biography
Osmotic pressure is the hydrostatic pressure produced by a solution in a space divided by a differentially permeable 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.
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.
www.arikah.com /encyclopedia/Osmotic_pressure   (401 words)

  
 Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal   (Site not responding. Last check: )
The osmotic pressure is defined to be the pressure (force per unit area) required to maintain an equilibrium, with no net movement of solvent.
Osmotic pressure is a colligative property, meaning that the property depends on the concentration of the solute but not on its identity.
The turgor pressure of a cell is largely maintained by osmosis, across the cell membrane, between the cell interior and its relatively hypotonic environment.
www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=osmosis   (1241 words)

  
 Osmosis
This is because the osmotic entry of water is opposed and eventually equalled by the pressure exerted by the cell wall, creating a steady state.
In fact, osmotic pressure is the main cause of support in plant leaves.
As mentioned before, osmosis is opposed by increasing the pressure in the region of high solute concentration with respect to that in the low solute concentration region.
www.dejavu.org /cgi-bin/get.cgi?ver=93&url=http://articles.gourt.com/%22http%3A%2F%2Farticles.gourt.com%2F%3Farticle%3Dosmotic   (1009 words)

  
 Osmosis Reverse Osmosis and Osmotic Pressure what they are
The conservation law of momentum requires that solute molecules, that generate osmotic pressure on the semi-permeable membrane, must generate, via the volume of the solution, the same osmotic pressure on all the solution boundaries, including its free surface.
When water flows through the membrane the pressure on the moving free surface of the solution is pushing it upward, and thus it is responsible to water pumping from the water arm to the solution arm.
The effect of the osmotic pressure on the free surface of the solution was first suggested by Hulett in 1902 [5], but received little attention.
members.tripod.com /~urila/index.htm   (975 words)

  
 Osmotic Pressure - Student Doctor Network Forums
I believe osmotic pressure is high outside of the cell, because the water is trying to push in.
Osmotic pressure is the pressure that must be applied to your cell membrane to PREVENT the water from coming inside when you place the cell in the hypotonic solution.
Now, the osmotic pressure is equivalent to the pressure necessary to stop the water from leaving the cell to go into the more concentrated solution surrounding it.
forums.studentdoctor.net /showthread.php?goto=lastpost&t=188643   (904 words)

  
 Osmotic pressure Summary
Osmotic pressure is a measure of the extra pressure that has to be exerted to counteract osmosis.
The osmotic pressure of a solution is the force that has to be exerted to halt osmosis.
If one solution has a lower osmotic pressure it is said to hypotonic to the more concentrated solution, which is termed the hypertonic solution.
www.bookrags.com /Osmotic_pressure   (557 words)

  
 MedFriendly.com: Osmotic pressure
The pressure that needs to be applied to a solution to stop the movement of a solvent into it, when the solution and solvent (such as water) are separated by a semipermeable membrane that only allows the solvent to pass through.
Osmotic pressure can prevent osmosis, which is the movement of a solvent (such as water) through a semipermeable membrane, from a solution that has a lower concentration of solutes to one that has a higher concentration of solutes.
Osmotic pressure depends on the amount of solute that is present in the solvent (such as water).
www.medfriendly.com /osmoticpressure.html   (446 words)

  
 Osmotic Pressure - Reverse Osmosis
Osmotic Pressure - Is the pressure required to prevent the flow of water across a semipermeable membrane separating two solutions having different ionic strengths.
For RO systems it is osmotic pressure that has to be overcome in order to produce permeate.
A “rule of thumb” is for every 100 mg/L of TDS difference between feed and permeate, 1 psi of osmotic pressure exists.
www.reverseosmosischemicals.com /osmotic-pressure.htm   (83 words)

  
 Sect. 1, Ch. 2: Osmotic Pressure   (Site not responding. Last check: )
Osmotic pressure is a function of the number of solute particles dissolved in the solution and the volume of the solution.
It follows that the osmotic pressure of a solution, referred to as osmolarity, is proportional to the concentration of solute in the solution.
C, osmotic pressure usually is expressed in terms of osmoles/liter.
www.lib.mcg.edu /edu/eshuphysio/program/section1/1ch2/s1ch2_16.htm   (167 words)

  
 Properties of Electrolyte Solutions
The pressure that must be applied to the side of the concentrated solution to prevent the flow of the pure solvent into the solution is called the osmotic pressure of the solution.
Osmotic pressure is important from a biological viewpoint since the physiological membranes (e.g., red blood cell membranes) are semipermeable membranes.
The effect of osmotic pressure on the red blood cells (RBC) can be demonstrated by suspending them in a solution of e.g., five percent sodium chloride solution which is of greater osmotic pressure than their contents.
www.utmem.edu /physpharm/.010.html   (2844 words)

  
 Influence of osmotic pressure changes on the opening of existing cracks in 2 intervertebral disc models.
To investigate the influence of decreasing osmotic pressure on the opening of cracks in the disc.
The osmotic pressure was changed in hydrogel samples with a crack, which was visualized with a confocal laser scanning microscope (Zeiss, Göttingen, Germany).
Decreasing osmotic pressure in a degenerating intervertebral disc enhances the opening of existing cracks, despite the concomitant decrease in anular stresses.
www.galenicom.com /medline/article/16845351/mt:Osmotic%252520Pressure   (300 words)

  
 THE EFFECT OF SOIL AMMONIUM CONCENTRATION AND OSMOTIC PRESSURE ON SEEDLING EMERGENCE   (Site not responding. Last check: )
It is not possible to distinguish the absolute effect of ammonia toxicity from the osmotic effect because the ammonium ion from which the ammonia is generated in the soil solution also creates an osmotic pressure.
This experiment was designed to separate the ammonia (toxicity and inherent osmotic pressure) and osmotic pressure effects for various species, and to discover whether ammonia toxicity and osmotic pressure are additive in their effects on plant emergence.
At the lowest osmotic pressure, emergence of canola was 90 % (4.5 plants emerged from 5 seeds sown), whereas at the highest osmotic pressure canola failed to emerge (Table 1).
www.regional.org.au /au/asa/1996/contributed/219dowling.htm   (1332 words)

  
 Semipermeable
At equilibrium the osmotic pressure of the stressing solution is identical to the osmotic pressure stressing the subphase.Credit: NICHD.
As the external osmotic pressure stresses the subphase, water (as well as small solutes) is exchanged across the semipermeable membrane.
Osmotic stress can be generated even when no semipermeable membrane is present to define the subphase.
www.websters-online-dictionary.org /definition/english/se/semipermeable.html   (539 words)

  
 Osmosis Reverse Osmosis and Osmotic Pressure what they are
Since the velocity is the same as that of a free molecule, the pressure will be the same as the pressure of an ideal gas of the same molecular concentration.
The osmotic pressure does not depend on the solute type, or its molecular size, but only on its molar concentration, as the formula states.
The system will stabilize when the osmotic pressure is balanced by the hydrostatic pressure generated by the difference h in the water levels.
urila.tripod.com   (897 words)

  
 Reference.com/Encyclopedia/Oncotic pressure
In blood plasma, the dissolved compounds have an osmotic pressure.
The difference between the osmotic pressure exerted by plasma proteins (colloidal osmotic pressure) in blood plasma and that exerted by tissue fluid proteins is called the oncotic pressure.
Because large plasma proteins can't easily cross through the capillary walls, their effect on the osmotic pressure of the capillary interiors will, to some extent, balance out the tendency for fluid to leak out of the capillaries.
www.reference.com /browse/wiki/Oncotic_pressure   (166 words)

  
 Corn fungus is nature's master blaster
Basically, the gun is powered by the buildup of pressure inside the spore-containing fungal fruiting body, called the perithecium, due to the ability of sap to create an osmotic pressure.
Such pressure is due to water flowing across a membrane into the perithecium as it tries to equalize the concentration of a salt solution inside the chamber.
In the case of the fungus, at question was whether the sugar mannitol or potassium ions were responsible for the osmotic pressure that generated the propulsive force.
www.eurekalert.org /pub_releases/2005-07/du-cfi072505.php   (693 words)

  
 Why you should install a Watermaid Salt Water Chlorinator
Osmotic pressure is an expression that relates to the behaviour of salt in a pool water solution.
When the osmotic pressure of the pool water solution is low then the pressure that causes water to diffuse across the semi-permeable membrane of a cell is high.
Since the pressures on each side of the cell membrane are not equal, there is a net transfer of fluid from the pool and into the cell.
www.watermaid.ca /14.htm   (3128 words)

  
 Diffusion and Osmosis
It is customary to express this tendency toward solvent transport in pressure units relative to the pure solvent.
A positive pressure must be exerted on the solution to prevent osmotic transport, again congruent with the concept that the osmotic pressure of the pure solvent is relatively "high".
One approach to the measurement of osmotic pressure is to measure the amount of hydrostatic pressure necessary to prevent fluid transfer by osmosis.
hyperphysics.phy-astr.gsu.edu /hbase/kinetic/diffus.html   (771 words)

  
 Osmotic Pressure of Salt-Free Polyelectrolyte Solutions: A Monte Carlo Simulation Study   (Site not responding. Last check: )
The osmotic pressure of salt-free polyelectrolyte solutions is studied using Monte Carlo simulations.
In dilute solutions, the dominant contribution to the excess part of the osmotic pressure comes from electrostatic interactions, resulting in an osmotic coefficient that decreases with increasing concentration.
By considering different terms in the pressure equation, the excess part of the osmotic coefficient is decomposed into polymer-polymer, polymer-counterion, and counterion-counterion contributions.
pubs.acs.org /cgi-bin/abstract.cgi/mamobx/2005/38/i02/abs/ma0486952.html   (238 words)

  
 Osmosis and Thermodynamics
Therefore, the osmotic pressure of the particles dissolved within the liquid is equal to the ideal gas pressure in the gas phase.
The identity of van't Hoff's formula of the osmotic pressure to the formula of the ideal gas pressure is, therefore, a direct and fundamental consequence of the second law of thermodynamics.
The pressure comes from the molecular attraction forces at the liquid boundary, and it is by far higher than the osmotic pressure.
urila.tripod.com /osmotic.htm   (2097 words)

  
 Plant Physiology Online: Alternative Conventions for Components of Water Potential
It is the hydrostatic pressure of the solution, and may be positive, as in turgid cells, or negative, as in xylem water.
"Osmotic pressure" is the term that physical chemists, zoologists, and many others use to denote the effect of dissolved solutes on the free energy of water.
Thus, π is sometimes incorrectly called osmotic potential instead of osmotic pressure, and it may be used either as a positive quantity or as a negative quantity.
www.plantphys.net /article.php?ch=t&id=27   (258 words)

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