Precipitation (chemistry)

2007-09-02T20:35:54Z

69.245.129.145: /* Cation sensitivity */

{{For|the band Interpol's EP|Precipitate EP}}

'''Precipitation''' is the formation of a [[solid]] in a [[solution]] during a [[chemical reaction]]. When the chemical reaction occurs the solid formed is called the '''precipitate'''. This can occur when an insoluble substance, the '''precipitate''', is formed in the solution due to a reaction or when the solution has been ''supersaturated'' by a compound. The formation of a precipitate is a sign of a chemical change. In most situations, the solid forms ("falls") out of the solute phase, and sinks to the bottom of the solution (though it will float if it is less dense than the solvent, or form a [[suspension (chemistry)|suspension]]).

Precipitation reactions can be used for making pigments, removing salts from water in water treatment, and for qualitative chemical analysis.

This effect is useful in many industrial and scientific applications whereby a chemical reaction may produce a solid that can be collected from the solution by various methods (e.g. filtration, decanting, centrifuging). Precipitation from a [[solid solution]] is also a useful way to [[precipitation strengthening|strengthen]] [[alloy]]s, this process is known as [[solid solution strengthening]].

An important stage of the precipitation process is the onset of [[nucleation]]. The creation of a hypothetical solid particle includes the formation of an interface, which requires some energy based on the relative [[surface energy]] of the solid and the solution. If this energy is not available, and no suitable nucleation surface is available, [[supersaturation]] occurs.

An example of a precipitation reaction: Aqueous silver nitrate (AgNO3) is added to a solution containing potassium chloride (KCl) and the precipitation of a white solid, silver chloride is observed. (Zumdahl, 2005)

:AgNO3(aq) + KCl(aq) → AgCl(s) + KNO3(aq)

The silver chloride(AgCl) has formed a solid, which is observed as a precipitate.

This reaction can be written emphasizing the dissociated ions in a combined solution
:Ag+(aq) + NO3-(aq) + K+(aq) + Cl-(aq) → AgCl(solid) + K+(aq) + NO3-(aq)

A final way to represent a precipitate reaction is known as a ''net ionic reaction''. In this case, any spectator ions (those which do not contribute to the reaction) are left out of the formula completely. This simplifies the above equations to the following:
:Ag+(aq) + Cl-(aq) → AgCl(s)

After evaporation, condensation occurs and will slowly turn into a cloud.

==Cation sensitivity==prescipitateion is a chemical reaction

==Digestion==

Digestion, or ''precipitate ageing'', happens when a freshly-formed precipitate is left, usually at a higher temperature, in the solution from which it is precipitated. It results in cleaner and bigger particles.<ref>[http://www.ktf-split.hr/glossary/en_o.php?def=digestion Chemical dictionary definition.]</ref>

==References==
*Zumdahl, Steven S. ''Chemical Principles.'' 4th ed. New York: Houghton Mifflin Company, 2005.
*Mark Smith ''Principles of Science'' 1993

<references/>

==Further reading==
*Banert, T., Brenner, G., Peuker, U. A. (2006), Operating parameters of a continuous sono-chemical precipitation reactor, Proc. 5. WCPT, Orlando Fl., 23.-27. April 2006.

==External links==
* [http://www.hci.edu.sg/~limth/lessons/2002/qa/cations.htm Test for Cations]
* [http://www.hielscher.com/ultrasonics/precipitation_01.htm Continuous Precipitation Using Ultrasonication (e.g. for nano-size magnetite particles)]

[[Category:Chemical processes]]

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Archive:Fanboy

2006-09-27T04:41:53Z

69.245.125.255: /* Common fanboy groups */

{{Otheruses3|Fanboys}}

'' '''Fanboy''' '' or '' '''fanboi''' '' is a term used to describe an individual (usually male, though the feminine version ''fangirl'' may be used for females) who is utterly devoted to a single fannish subject, or to a single point of view within that subject, often to the point where it is considered an [[obsession]].

==History of fanboys and the term==
The term originated in [[comic book]] circles, to describe someone who immersed himself in the fictional worlds of comics and the culture of comics fandom. The term is often used in a derogatory manner by other less obsessed fans. In the songs of the fannish [[parody]] [[musician]] [[Luke Ski]], many characters proudly consider themselves ''fanboys''. The term is most commonly associated with adolescent and teen males but can be applicable to any age or sex. Common subjects of reverence by fanboys are [[TV show]]s, [[film|movie]]s, [[music]], [[anime]], [[car]]s, [[video game console]]s, [[video games]], [[operating system]]s, [[MMORPG]]s, and [[software]] companies.

The stereotypical image of the fanboy is as an unkempt, socially awkward, young man who may be perceived as a loud mouthed [[pseudo-intellectual]]. A popular depiction of this stereotype is the [[Comic Book Guy]] on ''[[The Simpsons]]''.

The earliest use of the word "fanboy" has been dated to 1982, to the cover of the "Official Underground and Newave Comix Price Guide". On this cover page are sketched overweight, overzealous comic book collectors wearing T-shirts that state "Fanboys of America," and are describing the extreme measures they would go to, including moving to San Francisco to preserve their comics. Another early use is in a smart-alec editorial reply by "[[Ambush Bug]]" to a letter in his comic in [[1985]].

==Common fanboy groups==
There are several fanboy groups, and below are a few of these.
Many fanboys endorse a particular brand or product, some without even questioning the quality of competing products.

*The [[graphics processing unit]] (GPU) company [[ATI]]
*The competing GPU company [[nVidia]]
*The [[computer]] [[microprocessor]] company [[AMD]]
*The competing microprocessor company [[Intel]]
*The [[automobile]] companies Ford, General Motors, and Daimler Chrysler
*The [[cola]] product [[Coke]], from the [[Coca-Cola company]]
*The competing cola product Pepsi, from [[PepsiCo]]
*The competing [[PSP]] and [[DS]]

==Trivia==
The word "fanboys" can be a [[mnemonic]] [[acronym]] for the [[Grammatical conjunction|coordinating conjunction]]s of the [[English language]]: "for", "and", "nor", "but", "or", "yet", and "so".

==Media==
===Comic Book===
*[[Sergio Aragonés]]' ''Fanboy''
*Doug Holverson's "Fanboy" (anthropomorphized rotary fan obsessed with comics, who uses his electrical plug for a hand). Dates from the prolific minicomic wave of the 1980s.

===Television===
*''[[The Simpsons]]'''s [[Comic Book Guy]] refers to himself as a fanboy.
*''[[Freakazoid!|Freakazoid]]'''s [[freakazoid!#Other_characters|Fan Boy]]

===Radio/Podcasts===
*[[Fanboy Radio]] - [http://fanboyradio.com]
*Drooling FanBoy - [http://droolingfanboy.com]
*ifanboy - [http://www.ifanboy.com]
*[[The Fanboy Smackdown Podcast]] - [http://www.fanboysmackdown.com]

===Webcomics===
*Fanboy Almanac (webcomic) - [http://fanboyalmanac.com Fanboy Almanac]
*[http://www.ngeb.net/fanboys Fanboys web comic]
*[http://www.fogclub.net Fanboy Otaku Gamers Club web comic]
*[http://www.fanboysonline.com Fanboys!! Beyond Geekdom!!! (webcomic)]
*[http://www.fanboys-online.com Fanboys-Online]

===Video Games===
*[http://www.dsfanboy.com DS Fanboy]
*[http://www.pspfanboy.com PSP Fanboy]
*[http://www.nintendowiifanboy.com Nintendo Wii Fanboy]
*[http://www.xbox360fanboy.com Xbox 360 Fanboy]

==See also==
* [[Addiction]]
* [[Otaku]]
* [[Anorak (slang)|Anorak]]

== External links ==
* [http://www.urbandictionary.com/define.php?term=fanboy Urban dictionary: fanboy]
* [http://www.netjak.com/review.php/1013 Dissecting the Fanboy Mind] - A discussion of the fanboy behavior in regards to video games.

[[Category:Fandom]]
[[Category:Anime and manga terminology]]
[[de:Fanboy]]

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Precipitation (chemistry)

Archive:Fanboy