In chemistry, the osmole (Osm) is a non-SI unit of measurement that defines the number of moles of a chemical compound that contribute to a solution's osmotic pressure. Chemistry (from Egyptian kēme (chem meaning "earth") is the Science concerned with the composition structure and properties The mole (symbol mol) is a unit of Amount of substance: it is an SI base unit, and almost the only unit to be used to measure this A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. In Chemistry, a solution is a Homogeneous Mixture composed of two or more substances Osmotic pressure is the hydrostatic pressure produced by a difference in concentration between solutions on the two sides of a surface such as a semipermeable membrane
Osmolarity is a measure of the osmoles of solute per liter of solution, while the osmolality is a measure of the osmoles of solute per kilogram of solvent. The litre or liter (see spelling differences) is a unit of Volume. In Chemistry, a solution is a Homogeneous Mixture composed of two or more substances A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. Molarity and Osmolarity are not commonly used in osmometry because they are temperature dependent; that is, water changes its volume with temperature. However, if the concentration is very low, osmolarity and osmolality are considered equivalent. In Chemistry, concentration is the measure of how much of a given substance there is mixed with another substance In calculations for these two measurements, salts are presumed to dissociate into their component ions. Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge For example, a mole of glucose in solution is one osmole, whereas a mole of sodium chloride in solution is two osmoles (one mole of sodium and one mole of chloride). Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. For sodium chloride in the diet see Salt. Sodium chloride, also known as common salt, table salt, or Halite, is a Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 The chloride Ion is formed when the element Chlorine picks up one Electron to form an Anion (negatively-charged ion Cl&minus Both sodium and chloride ions affect the osmotic pressure of the solution.
The osmolarity of a solution of can be calculated from the following expression:
where
- φ is the osmotic coefficient, which accounts for the degree of non-ideality of the solution. In the simplest case it is the degree of dissociation of the solute. Then, φ is between 0 and 1 where 1 indicates 100% dissociation. However, φ can also be larger than 1 (e. g. for sucrose). For salts, electrostatic effects cause φ to be smaller than 1 even if 100% dissociation occurs (see Debye-Hückel equation);
- n is the number of particles (e. The Debye-Hückel limiting law, named for its developers Peter Debye and Erich Hückel, provides one way to obtain Activity coefficients. g. ions) into which a molecule dissociates. For example: glucose has n of 1, while NaCl has n of 2;
- C is the molar concentration of the solute;
- the index i represents the identity of a particular solute. Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology.
Osmolarity is expressed in units of osmoles per liter of solution (Osm/L), while osmolality is defined as osmoles per kilogram solvent (Osm/kg).
Osmolality can be measured using an osmometer which measures colligative properties, such as Freezing-point depression, Vapor pressure, or Boiling-point elevation. An osmometer is a device for measuring the Osmotic strength of a Solution, Colloid, or compound. Colligative properties are properties of solutions that depend on the number of particles in a given volume of solvent and not on the mass of the particles Freezing-point depression describes the phenomenon that the freezing point of a Liquid (a Solvent) is depressed when another compound is added meaning Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium Boiling-point elevation describes the phenomenon that the Boiling point of a Liquid (a Solvent) will be higher when another compound is added meaning that
Osmolality/osmolarity vs. tonicity
While similar, osmolarity and tonicity are not the same. Tonicity is a measure of blood capacity or effective osmolality in cell Biology. The key difference between the two is osmolarity is a measure of all solutes in solution, whereas toncity is a measure of impermeable solutes. Osmolarity compares the amount of solutes in two solutions, whereas tonicity compares the osmostic pressure gradient. If a solution in compartment A is hypertonic to a solution in compartment B, water will flow from compartment B to compartment A in an effort to dilute the solutes in compartment A. Tonicity is a measure of blood capacity or effective osmolality in cell Biology. This allows the two compartments to have equal solute concentration.
The derivatives of the term: isosmotic, hyperosmotic, and hypoosmotic, should not be confused with isotonic, hypertonic and hypotonic. Osmolarity is a measure of the osmoles of solute per Liter of solution while the osmolality is a measure of the osmoles of Solute per Kilogram Tonicity is a measure of blood capacity or effective osmolality in cell Biology. Tonicity is a measure of blood capacity or effective osmolality in cell Biology. Tonicity is a measure of blood capacity or effective osmolality in cell Biology. Tonicity is a measure of blood capacity or effective osmolality in cell Biology. Tonicity is a measure of blood capacity or effective osmolality in cell Biology.
Example: Solution A contains 2 mM of sucrose (impermeable) and 5 mM of urea (permeable)
Solution B contains 2 mM of sucrose (impermeable)
Solution A is hyperosmotic to solution B because it contains more total solutes.
Solution A is isotonic to solution B because the amount of impermable solutes is equal. Therefore, there is no osmotic pressure or water flow.
See also
References
In Chemistry, concentration is the measure of how much of a given substance there is mixed with another substance In Chemistry, concentration is the measure of how much of a given substance there is mixed with another substance Plasma osmolality is a measure of the concentration of substances such as Sodium, Chloride, Potassium, Urea, Glucose, and other Tonicity is a measure of blood capacity or effective osmolality in cell Biology.Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic