In chemistry, saturation has four different meanings: Chemistry (from the Greek word χημεία (chemeia) meaning cast together or pour together) is the science of matter at the atomic to molecular scale, dealing primarily with collections of atoms (such as molecules, crystals, and metals). ...

1. In physical chemistry, saturation is the point at which a solution of a substance can dissolve no more of that substance and additional amounts of that substance will appear as a precipitate. This point of maximum concentration, the saturation point, depends on the temperature of the liquid as well as the chemical nature of the substances involved. This can be used in the process of recrystallisation to purify a chemical: it is dissolved to the point of saturation in hot solvent, then as the solvent cools and the solubility decreases, excess solute precipitates. Impurities, being present in much lower concentration, do not saturate the solvent and so remain dissolved in the liquid. If a change in conditions (e.g. cooling) means that the concentration is actually higher than the saturation point, the solution has become supersaturated.
2. In physical chemistry, when referring to surface processes, saturation denotes the degree of which a surface is full of something. For example, base saturation refers to the fraction of exchangeable cations that are base cations. Similarly, in soil chemistry soil moisture saturation means that all voids are filled with water and thus all surfaces are wetted, and nitrogen saturation means that an ecosystem, such as a soil, can not store any more nitrogen.
3. In organic chemistry, a saturated compound has the maximum amount of hydrogens possible: i.e., no double bonds or, in a hydrocarbon chain, every carbon atom is attached to two hydrogen atoms. Of simple hydrocarbons, alkanes are saturated, and alkenes are unsaturated. The degree of unsaturation is a method of specifying the amount that a compound is partially saturated. In the modern treatment of electronic structure, unsaturated compounds are characterized by pi electron systems. The term is applied similarly to the fatty acid constituents of lipids, where the fat is described as saturated or unsaturated, depending on whether the constituent fatty acids contain carbon-carbon double bonds. Unsaturated is used when any carbon structure contains double or occasionally triple bonds. Many vegetable oils contain fatty acids with one (monounsaturated) or more (polyunsaturated) double bonds in them.
4. In biochemistry, the term saturation refers to the fraction of total protein binding sites that are occupied at any given time.

Physical Chemistry is the combined science of physics, chemistry, thermodynamics, and quantum mechanics which functions to provide molecular-level interpretations of observed macroscopic phenomena. ... Dissolving table salt in water In chemistry, a solution is a homogeneous mixture composed of one or more substances, known as solutes, dissolved in another substance, known as a solvent. ... In chemistry, concentration is the measure of how much of a given substance there is mixed with another substance. ... Dew on a spider web The dew point or dewpoint of a given parcel of air is the temperature to which the parcel must be cooled, at constant barometric pressure, for the water vapor component to condense into water, called dew. ... Recrystallization is an essentially physical process that has meanings in chemistry and geology. ... In physics, the term supersaturation or oversaturation refers to a solution that contains more of the dissolved material than could be dissolved by the solvent under existing circumstances. ... Physical Chemistry is the combined science of physics, chemistry, thermodynamics, and quantum mechanics which functions to provide molecular-level interpretations of observed macroscopic phenomena. ... This article does not cite its references or sources. ... This article does not cite its references or sources. ... SOiL is a five-piece aggressive rock/Nu Metal band from Chicago, formed in 1997 by ex-members of renowned death metal acts Broken Hope and Oppressor. ... This article or section does not cite its references or sources. ... Organic chemistry is a specific discipline within the subject of chemistry. ... An alkane in organic chemistry is a saturated hydrocarbon without cycles, that is, an acyclic hydrocarbon in which the molecule has the maximum possible number of hydrogen atoms and so has no double bonds. ... An alkene in organic chemistry is an unsaturated hydrocarbon containing at least one carbon to carbon double bond. ... The degree of unsaturation formula is used in organic chemistry to help draw chemical structures. ... A unsaturated compound in chemistry is a chemical compound that contains carbon - carbon pi bonds such as a alkene or a alkyne. ... This article or section does not cite its references or sources. ... A binding site is a region on a protein to which specific ligands bind. ...

See also

• Saturated fat
• Unsaturated fat