Osmotic pressure definition

The concentration (and therefore the osmotic pressure) of the solution depends on the extent of the surface. The definition ... 

Isotonic solutions, by definition, exert equal osmotic pressure. Therefore, for blood is the same as I I for the glucose solution. We can calculate from Equation after converting the concentration moles per liter —MRT and... 

By definition, Lnjl > 0. The sign of Js is determined by the sign of the cross coefficient Lvjr and its absolute value. If Lv <0, the volume flux of the solvent occurs in the direction from more dilute to more concentrated solutions (i.e. in the direction of the osmotic pressure gradient). If LVJt is smaller than then the solute flows in the direction of the drop of... 

If a solution and the pure solvent are separated by a semipermeable membrane, the solvent tends to pass through the membrane into the solution, and the osmotic pressure is the pressure that must be applied to the latter to keep the solvent from entering into it. The term osmotic pressure of the solution is, therefore, strictly speaking, incorrect, as osmotic pressure is, according to the definition, produced only when the solution is separated from the solvent by a semipermeable membrane. If this is remembered, it disposes of the objection sometimes raised that osmotic pressure works the wrong way, in that it causes motion from places of lower to places of higher osmotic pressure. It is osmosis which causes osmotic pressure, and not osmotic pressure which produces osmosis. 

However, let note, that the assumption about independence of the osmotic pressure of semi-diluted solutions on the length of a chain is not physically definitely well-founded per se it is equivalent to position that the system of strongly intertwined chains is thermodynamically equivalent to the system of gaped monomeric links of the same concentration. Therefore, both Flory-Huggins method and Scaling method do not take into account the conformation constituent of free energy of polymeric chains. 

We shall see that measurement of the osmotic pressure of a polydisperse system permits the experimental evaluation of M (Chapter 3), and light scattering experiments enable us to measure Mw (Chapter 5). It follows from the definition of these various averages that... 

Sodium, potassium, and chloride are electrolytes found in cow s milk for which the Food and Nutrition Board has estimated safe and adequate daily dietary intakes for infants, children and adolescents, and adults (NAS 1980A). Sodium functions in the body to maintain blood volume and cellular osmotic pressure and to transmit nerve impulses (NAS 1980A). The estimated safe and adequate daily dietary intake of sodium is 1100-3300 mg (2.8-8.4 g sodium chloride) for healthy adults (NAS 1980A). The American Medical Association, Council on Scientific Affairs (1979), suggested 4800 mg sodium per day as a tentative definition of moderation in sodium intake. 

By definition osmotic pressure equals the pressure that has to be applied onto a mobile semi-permeable membrane (filter) separating foam and liquid in order to prevent liquid phase from entering the foam. This pressure can be calculated as the difference between pressure of liquid column and pressure of foam column, both having the same height [84]... 

To obtain a familiar form for expressing the osmotic pressure, we can incorporate the approximation for In aw given by Equation 2.9 into the definition of osmotic pressure given by Equation 2.7 (RT In aw = —Vwn), which yields... 

From the definition of chemical potential (Eq. 2.4) and the formal expression for osmotic pressure (Eq. 2.7), we can express the chemical potential of water (pw) as... 

Such a large osmotic pressure, caused by the high concentrations of sucrose and other solutes, suggests that active transport is necessary at some stage to move certain photosynthetic products from leaf mesophyll cells to the sieve elements of the phloem. From the definition of water potential, = P — II + pwgh (Eq. 2.13a), we conclude that the hydrostatic pressure in the phloem of a leaf that is 10 m above the ground is... 

As we mentioned earlier in this section, it was van t Hoff who saw an analogy between the properties of dilute solutions and the gas laws. Just as an equation of state can be written for an ideal gas, so can an equation of state be written for an ideal solution in terms of its osmotic pressure, as shown in Table 12-2. It is then a straightforward matter of remembering the definition of a mole (the weight of something divided by its molecu-... 

Suppo.se that a colligative property of the polymer solution is measured. These are properties that depend on the number of dissolved solute molecules and not on their sizes (see also Section 2.10). Osmotic pressure, vapor pressure lowering, and freezing point depression are some examples of colligative properties. If the value of the property measured is P, then by definition... 

By definition, UF membranes are freely permeable to inorganic salts and other molecules with MW less than about 1000. Because it is these species that generally create most of the osmotic pressure of solutions, the net osmotic pressure difference across UF membranes is generally quite small and therefore small applied pressures can be used. Because these membranes are more open than RO membranes, there is less necessity to produce very thin membranes in order to achieve high water fluxes. 

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