Precipitation is the creation of a solid of a solution. When the reaction occurs in the liquid solution, the formed solid is called 'sediment'. Chemicals that cause solids are formed are called 'precipitants'. Without adequate gravity (precipitation) to bring solid particles together, the precipitate remains in suspension. After sedimentation, especially when using a centrifuge to press it into a compact mass, the precipitate may be referred to as a 'pellet'. Precipitation can be used as a medium. The remaining free liquid deposits on solids are called 'supernatants' or 'supernatants'. Powders derived from rainfall historically are also known as 'flowers'. When solids appear in the form of cellulosic fibers that have gone through a chemical process, this process is often referred to as regeneration .
Sometimes the formation of precipitates indicates the occurrence of chemical reactions. If the silver nitrate solution is poured into a sodium chloride solution, a chemical reaction occurs forming a silver chloride silver precipitate. When the potassium iodide solution reacts with lead (II) nitrate solution, the yellow precipitate of lead (II) iodide is formed.
Precipitation may occur if the concentration of a compound exceeds its solubility (such as when mixing the solvent or changing their temperature). Precipitation can occur quickly from a saturated solution.
In solids, precipitation occurs when the concentration of one solid is above the solubility limit of the host, for example. rapid quenching or ion implantation, and the temperature is high enough that diffusion can cause segregation to be precipitate. Precipitation in solids is routinely used to synthesize nanoclusters.
An important stage of the precipitation process is the beginning of nucleation. The creation of hypothetical solid particles includes the formation of interfaces, which require some energy based on the relative surface energy of solids and solutions. If this energy is not available, and no suitable nucleation surface is available, saturation occurs.
Video Precipitation (chemistry)
Apps
Precipitation reactions can be used to make pigments, remove salts from water in water treatment, and in classical qualitative inorganic analyzes.
Precipitation is also useful for isolating the reaction product during inspection. Ideally, the reaction product does not dissolve in the reaction solvent. Thus, the precipitate is formed, preferably forming pure crystals. An example of this is the synthesis of porphyrins in refined propionic acid. By cooling the reaction mixture to room temperature, the porphyrin precipitate crystals, and collected by filtration:
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Precipitation may also occur when an antisolvent (solvent in which the product is insoluble) is added, drastically reducing the desired product solubility. After that, the precipitate can be easily separated by filtration, thinning, or centrifugation. An example is chromic synthesis of tetrafenilporphyrin chloride: water is added to the DMF reaction solution, and the product precipitates. Precipitation is also useful in purifying the product: crude Bmim-Cl is taken in acetonitrile, and falls into ethyl acetate, where it precipitates. Another important application of antisolvent is in the deposition of DNA ethanol.
In metallurgy, the deposition of a solid solution is also a useful means of strengthening the alloy; This process is known as solid solution reinforcement.
Maps Precipitation (chemistry)
Representation using chemical equations
Contoh reaksi pengendapan: perak nitrat berair (AgNO 3 ) ditambahkan ke larutan yang mengandung kalium klorida (KCl), pengendapan dari padatan putih, perak klorida (AgCl), diamati. (Zumdahl, 2005)
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The silver chloride (AgCl) has formed solid, which is observed as sediment.
Reaksi ini dapat ditulis dengan menekankan ion terdisosiasi dalam larutan gabungan. Ini dikenal sebagai persamaan ionik.
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The last way to represent a precipitate reaction is known as the clean ionic reaction . In this case, every ion of the audience (which does not contribute to the reaction) is not included in the formula completely. This simplifies the above equation as follows:
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Depth color
Many compounds containing metal ions produce precipitate with a distinctive color. The following are typical colors for various metals. However, many of these compounds can produce very different colors than those listed.
Other compounds generally form white precipitates.
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Analysis of anion/cation
Sludge formations are useful in detecting cation types in salts. To do this, the first alkali reacts with an unknown salt to produce a precipitate ie the unknown salt hydroxide. To identify the cation, the color of the precipitate and its excess solubility is recorded. A similar process is often used sequentially - for example, a solution of barium nitrate will react with sulfate ions to form solid barium sulphate deposits, indicating that it is possible that sulfate ions are present.
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Digestion
Digestion, or deposition of aging , occurs when newly formed deposits are allowed, usually at higher temperatures, in the solution it deposits. This results in cleaner and larger particles. The physico-chemical process underlying digestion is called Ostwald ripening.
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See also
- Coprecipitation
- Overlay in
- Smooth
- Effervescence
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References
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Further reading
- Zumdahl, Steven S. (2005). Chemical Principles (5th ed.). New York: Houghton Mifflin. ISBNÃ, 0-618-37206-7.
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External links
- The precipitation reaction of a particular cation
- Digestion Instruments
- Thesis about pattern formation in precipitation reactions
Source of the article : Wikipedia
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