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Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane. [1] It is also defined as the measure of the tendency of a solution to take in its pure solvent by osmosis .
For most non-electrolytes dissolved in water, the van 't Hoff factor is essentially 1. For most ionic compounds dissolved in water, the van 't Hoff factor is equal to the number of discrete ions in a formula unit of the substance. This is true for ideal solutions only, as occasionally ion pairing occurs in solution. At a given instant a small ...
Similarly, the combined ideal gas law, =, has as an analogue for ideal solutions =, where is osmotic pressure; V is the volume; n is the number of moles of solute; R is the molar gas constant 8.314 J K −1 mol −1; T is absolute temperature; and i is the Van 't Hoff factor.
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.
It is used in assessing the osmotic strength of colloids as well as solutions. [2] The freezing point depression osmometer operates by using the solution's freezing point to determine the concentration of the solution. It uses a nanoliter nanometer, a device that facilitates the establishment of the solution's melting and freezing points ...
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.
The red line on the chart to the right is the maximum concentration of water vapor expected for a given temperature. The water vapor concentration increases significantly as the temperature rises, approaching 100% (steam, pure water vapor) at 100 °C. However the difference in densities between air and water vapor would still exist (0.598 vs. 1 ...
Due to the increasing potential for a higher water vapor partial pressure at higher air temperatures, the water content of air at sea level can get as high as 3% by mass at 30 °C (86 °F) compared to no more than about 0.5% by mass at 0 °C (32 °F).