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precipitate

 
Dictionary: pre·cip·i·tate   (prĭ-sĭp'ĭ-tāt') pronunciation
 

v., -tat·ed, -tat·ing, -tates.

v.tr.
  1. To throw from or as if from a great height; hurl downward: “The finest bridge in all Peru broke and precipitated five travelers into the gulf below” (Thornton Wilder).
  2. To cause to happen, especially suddenly or prematurely. See synonyms at speed.
  3. Meteorology. To cause (water vapor) to condense and fall from the air as rain, snow, sleet, or hail.
  4. Chemistry. To cause (a solid substance) to be separated from a solution.
v.intr.
  1. Meteorology. To condense and fall from the air as rain, snow, sleet, or hail.
  2. Chemistry. To be separated from a solution as a solid.
  3. To fall or be thrown headlong: an ailing economy that precipitated into ruin despite foreign intervention.
adj. (-tĭt)
  1. Moving rapidly and heedlessly; speeding headlong.
  2. Acting with or marked by excessive haste and lack of due deliberation. See synonyms at impetuous, reckless.
  3. Occurring suddenly or unexpectedly.
n. (-tāt', -tĭt)
  1. Chemistry. A solid or solid phase separated from a solution.
  2. A product resulting from a process, event, or course of action.

[Latin praecipitāre, praecipitāt-, to throw headlong, from praeceps, praecipit-, headlong : prae-, pre- + caput, capit-, head.]

precipitately pre·cip'i·tate·ly (-tĭt-lē) adv.
precipitateness pre·cip'i·tate·ness n.
precipitative pre·cip'i·ta'tive adj.
precipitator pre·cip'i·ta'tor n.

USAGE NOTE   The adjective precipitate and the adverb precipitately were once applied to physical steepness but are now used primarily of rash, headlong actions: Their precipitate entry into the foreign markets led to disaster. He withdrew precipitately from the race. Precipitous currently means “steep” in both literal and figurative senses: the precipitous rapids of the upper river; a precipitous drop in commodity prices. But precipitous and precipitously are also frequently used to mean “abrupt, hasty,” which takes them into territory that would ordinarily belong to precipitate and precipitately: their precipitous decision to leave. This usage is a natural extension of the use of precipitous to describe a rise or fall in a quantity over time: a precipitous increase in reports of measles is also an abrupt or sudden event. Though this extended use of precipitous is well attested in the work of reputable writers, it is still widely regarded as an error.


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Chemistry Dictionary: precipitate
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A suspension of small solid particles produced in a liquid by chemical reaction.



 
Thesaurus: precipitate
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verb

    To put down, especially in layers, by a natural process: deposit. See increase/decrease.

adjective

  1. Characterized by unthinking boldness and haste: brash, foolhardy, harum-scarum, hasty, headlong, hotheaded, ill-considered, impetuous, improvident, impulsive, incautious, madcap, precipitant, rash1, reckless, slapdash, temerarious, unconsidered. See careful/careless.
  2. Happening quickly and without warning: abrupt, hurried, precipitant, sudden. See fast/slow/velocity, surprise/expect.

noun

  1. Matter that settles on a bottom or collects on a surface by a natural process: deposit, dreg (often used in plural), lees, precipitation, sediment. See leftover.
  2. Something brought about by a cause: aftermath, consequence, corollary, effect, end product, event, fruit, harvest, issue, outcome, ramification, result, resultant, sequel, sequence, sequent, upshot. See cause/effect.

 
Antonyms: precipitate
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v

Definition: hurry, speed
Antonyms: check, slow, wait


 
Dental Dictionary: precipitate
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(prē-sip′i-tāt)
n

An insoluble solid substance that forms from chemical reactions between solutions.

 
Science Dictionary: precipitate
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(pri-sip-uh-tayt, pri-sip-uh-tuht)

In chemistry, a solid material that is formed in a solution by chemical reactions and settles to the bottom of the container in which the reaction takes place. A precipitate may also be a substance removed from another by an artificial filter.

 
Veterinary Dictionary: precipitate
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1. to cause settling of a soluble substance in solution.
2. a deposit of solid particles settled out of a solution.
3. occurring with undue rapidity, as precipitate labor.

 
Devil's Dictionary: precipitate
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A cynical view of the world by Ambrose Bierce


adj.

Anteprandial.

    Precipitate in all, this sinner
    Took action first, and then his dinner.
                                                              Judibras


 
Word Tutor: precipitate
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pronunciation

IN BRIEF: To cause to happen. Also: To separate from a solution.

pronunciation It's queer how it is always one's virtues that precipitate one into disaster. — Rebecca West (1892-1983)

 
Wikipedia: Precipitation (chemistry)
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Chemical Precipitation

Precipitation is the formation of a solid in a solution during a chemical reaction. When the reaction occurs, the solid formed is called the precipitate, and the liquid remaining above the solid is called the supernate.

Natural methods of precipitation include settling or sedimentation, where a solid forms over a period of time due to ambient forces like gravity or centrifugation. During chemical reactions, precipitation may also occur particularly if an insoluble substance is introduced into a solution and the density happens to be greater (otherwise the precipitate would float or form a suspension). With soluble substances, precipitation is accelerated once the solution becomes supersaturated

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.

Contents

Applications

Crystals of meso-tetratolylporphyrin from refluxing propionic acid precipitate on cooling

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

Precipitation is also useful to isolate the products of a reaction during workup. Ideally, the product of the reaction is insoluble in the reaction solvent. Thus, it precipitates as it is formed, preferably forming pure crystals. An example of this would be the synthesis of porphyrins in refluxing propionic acid. By cooling the reaction mixture to room temperature, crystals of the porphyrin precipitate, and are collected by filtration:[1]

Precipitation may also occur when an antisolvent (a solvent in which the product is insoluble) is added, drastically reducing the solubility of the desired product. Thereafter, the precipitate may easily be separated by filtration, decanting, or centrifugation). An example would be the synthesis of chromic tetraphenylporphyrin chloride: water is added to the DMF reaction solution, and the product precipitates.[2] Precipitation is also useful in purifying products: crude bmim-Cl is taken up in acetonitrile, and dropped into ethyl acetate, where it precipitates.[3]

In metallurgy, precipitation from a solid solution is also a useful way to strengthen alloys; this process is known as solid solution strengthening.

Representation using chemical equations

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. This is known as the ionic equation.

Ag+ (aq) + NO3- (aq) + K+ (aq) + Cl- (aq) → AgCl (s) + 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)

Cation sensitivity

Precipitate formation is useful in the detection of the type of cation in salt. To do this, an alkali first reacts with the unknown salt to produce a precipitate which is the hydroxide of the unknown salt. To identify the cation, the color of the precipitate and its solubility in excess are noted. Similar processes are often used to separate chemically similar elements, such as the Alkali earth metals.

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.[4] The physico-chemical process underlying digestion is called Ostwald ripening.

References

  • Zumdahl, Steven S. Chemical Principles. 4th ed. New York: Houghton Mifflin Company, 2005.
  • Mark Smith Principles of Science 1993
  1. ^ A. D. Adler; F. R. Longo; J. D. Finarelli; J. Goldmacher; J. Assour; L. Korsakoff (1967). "A simplified synthesis for meso-tetraphenylporphine". J. Org. Chem. 32 (2): 476–476. doi:10.1021/jo01288a053. 
  2. ^ Alan D. Adler; Frederick R. Longo; Frank Kampas; Jean Kim (1970). "On the preparation of metalloporphyrins". Journal of Inorganic and Nuclear Chemistry 32: 2443. doi:10.1016/0022-1902(70)80535-8. 
  3. ^ Dupont, J., Consorti, C., Suarez, P., de Souza, R. (2004). "Preparation of 1-Butyl-3-methyl imidazolium-based Room Temperature Ionic Liquids". Org. Synth.; Coll. Vol. 10: 184. 
  4. ^ "Chemical dictionary definition". http://www.ktf-split.hr/glossary/en_o.php?def=digestion. Retrieved on 2008-02-26. 

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


 
Translations: Precipitate
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Dansk (Danish)
v. tr. - fremskynde, bundfælde, udskille
v. intr. - styrte
adj. - brat, hovedkulds
n. - bundfald

Nederlands (Dutch)
neerslaan (chemisch), neerslaan, condenseren, abrupt veroorzaken, slingeren, languit vallen, overhaasten, overhaastig, dat wat uit een oplossing neerslaat

Français (French)
v. tr. - (Chim, Météo, gén) précipiter
v. intr. - (Chim) précipiter, (Météo) être précipité
adj. - précipité, prompt
n. - (Chim) précipité

Deutsch (German)
v. - sich niederschlagen, stürzen, beschleunigen, ausfällen, kondensieren
adj. - überstürzt, eilig
n. - Niederschlag, Kondensat

Ελληνική (Greek)
v. - κατακρημνίζω, γκρεμίζω, επισπεύδω, (χημ.) υγροποιώ
adj. - βιαστικός, εσπευσμένος
n. - ίζημα, (χημ.) κατακρήμνισμα

Italiano (Italian)
precipitare, depositarsi, precipitato

Português (Portuguese)
v. - precipitar
adj. - precipitado
n. - precipitado (m)

Русский (Russian)
ввергнуть, выпадать (об осадках), ускорить, стремительный, опрометчивый, осадок

Español (Spanish)
v. tr. - precipitarse, condensarse
v. intr. - precipitarse, condensarse
adj. - precipitado
n. - precipitado

Svenska (Swedish)
v. - störta, påskynda, plötsligt framkalla, fälla ut (kem.), kondensera (fys.)
adj. - brådstörtad, plötslig, förhastad, besinningslös
n. - utfällning, kondensat

中文(简体)(Chinese (Simplified))
猛抛, 促成, 使陷入, 猛地落下, 突如其来的, 贸然轻率的, 陡然下降的, 沉淀物

中文(繁體)(Chinese (Traditional))
v. tr. - 猛拋, 促成, 使陷入
v. intr. - 猛地落下
adj. - 突如其來的, 貿然輕率的, 陡然下降的
n. - 沈澱物

한국어 (Korean)
v. tr. - 거꾸로 떨어뜨리다
v. intr. - 갑자기 빠지다
adj. - 거꾸로의, 줄달음치는
n. - 침전(물)

日本語 (Japanese)
n. - 沈殿物
v. - 真っ逆さまに落とす, 陥らせる, 沈殿する, 沈殿させる, 突然引き起こす, 凝結させる, 促進する
adj. - 大急ぎの, 軽率な

العربيه (Arabic)
‏(فعل) يلقي, يقذف, يندفع, يتهور (صفه) مترسب (الاسم) نتيجه, نتاج, ثمرة‏

עברית (Hebrew)
v. tr. - ‮זירז, החיש, הטיל, השליך, עיבה (גז לנוזל)‬
v. intr. - ‮יצר משקע מחומר הנמצא באוויר, הפריד חומר הנמצא בתמיסה‬
adj. - ‮נמהר, לא-שקול‬
n. - ‮חומר מופרד, משקע‬


 
 

 

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