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where is osmotic pressure, i is the dimensionless van 't Hoff index, c is the molar concentration of solute, R is the ideal gas constant, and T is the absolute temperature (usually in kelvins). This formula applies when the solute concentration is sufficiently low that the solution can be treated as an ideal solution .
The freezing point depression osmometer is an osmometer that is used in determining a solution's osmotic concentration as its osmotically active aspects depress its freezing point. In the past, freezing point osmometry has been used to assess the osmotic strength of colloids and solutions. The osmometer uses the solution's freezing point ...
For instance, for solutions of magnesium chloride, the vapor pressure is slightly greater than that predicted by Raoult's law up to a concentration of 0.7 mol/kg, after which the vapor pressure is lower than Raoult's law predicts. For aqueous solutions, the osmotic coefficients can be calculated theoretically by Pitzer equations [4] or TCPC model.
The pressure difference between the two compartments is the osmotic pressure. This can be calculate by measuring the change in height or measured directly with a flexible diaphragm. [2] Since the pressure is directly changed, an accurate measurement of osmotic pressure can be achieved in 10 – 30 minutes. [2]
The process stops and equilibrium is attained when the pressure difference equals the osmotic pressure. Two laws governing the osmotic pressure of a dilute solution were discovered by the German botanist W. F. P. Pfeffer and the Dutch chemist J. H. van’t Hoff: The osmotic pressure of a dilute solution at constant temperature is directly ...
Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution which in this case is represented by body fluid) to keep the body fluids from becoming too diluted or concentrated.
Thus, for every 1 mole of NaCl in solution, there are 2 osmoles of solute particles (i.e., a 1 mol/L NaCl solution is a 2 osmol/L NaCl solution). Both sodium and chloride ions affect the osmotic pressure of the solution. [2] [Note: NaCl does not dissociate completely in water at standard temperature and pressure, so the solution will be ...
An osmometer is a device for measuring the osmotic strength of a solution, colloid, or compound.. There are several different techniques employed in osmometry: Freezing point depression osmometers may also be used to determine the osmotic strength of a solution, as osmotically active compounds depress the freezing point of a solution.