Search results
Results from the WOW.Com Content Network
In simpler terms, osmolality is an expression of solute osmotic concentration per mass of solvent, whereas osmolarity is per volume of solution (thus the conversion by multiplying with the mass density of solvent in solution (kg solvent/litre solution).
When a measure of serum solutes is calculated, it is often done in units of osmolarity. While it is possible to convert between osmolality and osmolarity, [6] thereby deriving a more mathematically correct osmol gap calculation, in actual clinical practice this is not done. This is because the difference in absolute value of these two ...
Whereas osmolality (with an "l") is defined as the number of osmoles (Osm) of solute per kilogram of solvent (osmol/kg or Osm/kg), osmolarity (with an "r") is defined as the number of osmoles of solute per liter (L) of solution (osmol/L or Osm/L). As such, larger numbers indicate a greater concentration of solutes in the plasma.
For liquid solutions, the osmotic coefficient is often used to calculate the salt activity coefficient from the solvent activity, or vice versa. For example, freezing point depression measurements, or measurements of deviations from ideality for other colligative properties, allows calculation of the salt activity coefficient through the osmotic coefficient.
Osmolality is a variation of molality that takes into account only solutes that contribute to a solution's osmotic pressure. It is measured in osmoles of the solute per kilogram of water. This unit is frequently used in medical laboratory results in place of osmolarity , because it can be measured simply by depression of the freezing point of a ...
In the present day, the method is applied, among other areas, in measuring osmolarity in lens care solutions as well as eye drops. [8] It is further used in clinical chemistry, pharmaceutical, and quality control laboratories, where it facilitates different processes. As compared to the other methods, the freezing point depression osmometer has ...
Osm b = Body osmolarity before loss (almost equal to plasma osmolality of 275-299 milli-osmoles per kilogram [4]) TBW b = Total body water before loss (approximately 60% of body weight, or using tritiated water or deuterium) 2. The total amount of substance in the body after the loss is then estimated:
The van 't Hoff factor i (named after Dutch chemist Jacobus Henricus van 't Hoff) is a measure of the effect of a solute on colligative properties such as osmotic pressure, relative lowering in vapor pressure, boiling-point elevation and freezing-point depression.