Precipitation (chemistry)

precipitateprecipitationprecipitatessupernatantprecipitatedprecipitatingchemical precipitationprecipitation reactionprecipitantprecipitated out
Precipitation is the creation of a solid from a solution.wikipedia
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Solubility

solubleinsolublewater-soluble
Precipitation may occur if the concentration of a compound exceeds its solubility (such as when mixing solvents or changing their temperature).
Solubility occurs under dynamic equilibrium, which means that solubility results from the simultaneous and opposing processes of dissolution and phase joining (e.g. precipitation of solids).

Supersaturation

supersaturatedsupersaturateoversaturated
Precipitation may occur rapidly from a supersaturated solution.
The precipitation or crystallization of the solute takes longer than the actual cooling time because the molecules need to meet up and form the precipitate without being knocked apart by the solvent.

Pigment

pigmentspigmentationnatural pigment
Precipitation reactions can be used for making pigments, removing salts from water in water treatment, and in classical qualitative inorganic analysis.
In some cases, a pigment can be manufactured from a dye by precipitating a soluble dye with a metallic salt.

Crystallization

crystallizecrystallisationcrystallized
Thus, it precipitates as it is formed, preferably forming pure crystals.
Some of the ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas.

Nanoparticle

nanoparticlesnanoparticulatenanoclusters
Precipitation in solids is routinely used to synthesize nanoclusters.
There are several methods for creating nanoparticles, including gas condensation, attrition, chemical precipitation, ion implantation, pyrolysis and hydrothermal synthesis.

Centrifugation

centrifugal separationcentrifugedcentrifugated
Thereafter, the precipitate may easily be separated by filtration, decanting, or centrifugation.
Chemists and biologists may increase the effective gravitational force on a test tube so as to more rapidly and completely cause the precipitate (pellet) to gather on the bottom of the tube.

Decantation

decantingdecanteddecant
Thereafter, the precipitate may easily be separated by filtration, decanting, or centrifugation.
The layer closer to the top of the container—the less dense of the two liquids, or the liquid from which the precipitate or sediment has settled out—is poured off, leaving the other component or the more dense liquid of the mixture behind.

Work-up (chemistry)

work-upworkupaqueous workup
Precipitation is also useful to isolate the products of a reaction during workup.

Precipitation hardening

age hardeningprecipitation strengtheningprecipitation hardened
In metallurgy, precipitation from a solid solution is also a useful way to strengthen alloys; this process is known as solid solution strengthening.
Just as the formation of ice in air can produce clouds, snow, or hail, depending upon the thermal history of a given portion of the atmosphere, precipitation in solids can produce many different sizes of particles, which have radically different properties.

Silver nitrate

AgNO 3 nitrate of silverAgNO3
An example of a precipitation reaction: Aqueous silver nitrate (AgNO 3 ) is added to a solution containing potassium chloride (KCl), the precipitation of a white solid, silver chloride (AgCl), is observed.
Similarly, silver nitrate is used to prepare some silver-based explosives, such as the fulminate, azide, or acetylide, through a precipitation reaction.

Ethanol precipitation

precipitateprecipitatedprecipitation
Another important application of an antisolvent is in ethanol precipitation of DNA.
The same mechanism operates in the case of negatively charged phosphate groups on a DNA backbone: even though positive ions are present in solution, the relatively weak net electrostatic force prevents them from forming stable ionic bonds with phosphates and precipitating out of solution.

Gold

Aunative goldgold dust
Gold ions in solution are readily reduced and precipitated as metal by adding any other metal as the reducing agent.

Filtration

filterfilteredfiltrate
Thereafter, the precipitate may easily be separated by filtration, decanting, or centrifugation.
The use of filter aids is usually limited to cases where the cake is discarded or where the precipitate can be chemically separated from the filter.

Coprecipitation

coprecipitatesco-precipitationcoprecipitated
In chemistry, coprecipitation (CPT) or co-precipitation is carrying down a precipitate of substances normally soluble under the conditions employed.

Salting out

salting-outantisolventsalt out
The salt concentration needed for the protein to precipitate out of the solution differs from protein to protein.

Hydroxide

OHhydroxide ionOH −
To do this, an alkali first reacts with the unknown salt to produce a precipitate that is the hydroxide of the unknown salt.
The polymeric compounds M(OH) 2 and M(OH) 3 are in general prepared by increasing the pH of an aqueous solutions of the corresponding metal cations until the hydroxide precipitates out of solution.

Ostwald ripening

coarseningprecipitate aging
The physico-chemical process underlying digestion is called Ostwald ripening.
Ostwald ripening is also the key process in the digestion of precipitates, an important step in gravimetric analysis.

Settling

settleable solidssettling tanksettle
Without sufficient force of gravity (settling) to bring the solid particles together, the precipitate remains in suspension.

Suspension (chemistry)

suspensionsuspensionsaqueous suspension
Without sufficient force of gravity (settling) to bring the solid particles together, the precipitate remains in suspension.

Sedimentation

sedimentsedimentssedimentary
After sedimentation, especially when using a centrifuge to press it into a compact mass, the precipitate may be referred to as a 'pellet'.

Laboratory centrifuge

CentrifugeCentrifuge tubecentrifuges
After sedimentation, especially when using a centrifuge to press it into a compact mass, the precipitate may be referred to as a 'pellet'.

History of chemistry

chemistryburgeoning chemistrychemical revolution
Powders derived from precipitation have also historically been known as 'flowers'.

Cellulose

cellulolyticcellulosiccellulose ester
When the solid appears in the form of cellulose fibers which have been through chemical processing, the process is often referred to as regeneration.

Ion implantation

ion implantersimplantedion implanter
ion implantation, and the temperature is high enough that diffusion can lead to segregation into precipitates.

Nucleation

nucleatenucleatingnucleated
An important stage of the precipitation process is the onset of nucleation.