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Encyclopedia > Sublimation (chemistry)

Sublimation of an element or compound is a transition from the solid to gas phase so rapidly that the liquid phase cannot be observed. Sublimation is a phase transition that occurs at temperatures and pressures below the triple point (see phase diagram). Sublimation has three separate meanings: Sublimation (physics), the change from solid to gas without passing the liquid state Sublimation (psychology), the transformation of emotions Dye sublimation, the transference of printed images to a synthetic substrate by the application of heat Category: ... For other uses, see Solid (disambiguation). ... This article does not cite any references or sources. ... A liquid will usually assume the shape of its container A liquid is one of the main states of matter. ... In physics, a phase transition, (or phase change) is the transformation of a thermodynamic system from one phase to another. ... In physics, the triple point of a substance is the temperature and pressure at which three phases (gas, liquid, and solid) of that substance may coexist in thermodynamic equilibrium. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ...


At normal pressures, most chemical compounds and elements possess three different states at different temperatures. In these cases the transition from the solid to the gaseous state requires an intermediate liquid state. However, for some elements or substances at some pressures the material may transition directly from solid to the gaseous state. Note that the pressure referred to here is the vapor pressure of the substance, not the total pressure of the entire system. In chemistry and other sciences, STP or standard temperature and pressure is a standard set of conditions for experimental measurements, to enable comparisons to be made between sets of data. ... A chemical compound is a chemical substance of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... The periodic table of the chemical elements A chemical element, or element for short, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... Fig. ... In chemistry and physics, Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ...


The opposite of sublimation is deposition. The formation of frost is an example of meteorological deposition. Look up Antonym in Wiktionary, the free dictionary. ... It has been suggested that Deposition (meteorology) be merged into this article or section. ... Frost on black pipes Frost is a solid deposition of water vapor from saturated air. ... Deposition is the process by which, in sub-freezing air, water vapor changes directly to ice without first becoming a liquid. ...


Examples

Some materials (such as zinc and cadmium) will sublimate at low pressures and thus may be a problem encountered in high-vacuum applications. General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ... General Name, Symbol, Number cadmium, Cd, 48 Chemical series transition metals Group, Period, Block 12, 5, d Appearance silvery gray metallic Standard atomic weight 112. ... Look up Vacuum in Wiktionary, the free dictionary. ...


Carbon dioxide is a common example of a chemical compound that sublimates at atmospheric pressure—a block of solid CO2 (dry ice) at room temperature and at one atmosphere of pressure will turn into gas without first becoming a liquid. Iodine is another example of a substance that visibly sublimates at room temperature. In contrast to CO2, though, it is possible to obtain liquid iodine at atmospheric pressure by heating it. Snow and other water ices also sublimate, although more slowly, at below-freezing temperatures. This phenomenon, used in freeze drying, allows wet cloth to be hung outdoors in freezing weather and retrieved later in a dry state. Naphthalene, a common ingredient in mothballs, also sublimes slowly. Arsenic can also sublimate at high temperatures. Sublimation requires additional energy and is an endothermic change. The enthalpy of sublimation can be calculated as the enthalpy of fusion plus the enthalpy of vaporization. In order to meet Wikipedias quality standards, this article requires cleanup. ... Diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure at any point in the Earths atmosphere. ... In order to meet Wikipedias quality standards, this article requires cleanup. ... General Name, Symbol, Number iodine, I, 53 Chemical series halogens Group, Period, Block 17, 5, p Appearance violet-dark gray, lustrous Standard atomic weight 126. ... Snow is a type of precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. ... Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... Freeze drying (also known as Lyophilization) is a dehydration process typically used to preserve a perishable material, or to make the material more convenient for transport. ... Naphthalene (not to be confused with naphtha) (also known as naphthalin, naphthaline, tar camphor, white tar, albocarbon, or naphthene), is a crystalline, aromatic, white, solid hydrocarbon, best known as the primary ingredient of mothballs. ... Mothballs are small balls of chemical pesticide and deodorant used when storing clothing and other articles susceptible to damage from mold or moth larvae. ... General Name, Symbol, Number arsenic, As, 33 Chemical series metalloids Group, Period, Block 15, 4, p Appearance metallic gray Standard atomic weight 74. ... In thermodynamics, the word endothermic describes a process or reaction that absorbs energy in the form of heat. ... Standard enthalpy change of fusion of period three. ... The heat of vaporization is a physical property of substances. ...


Other substances, such as ammonium chloride, appear to sublime because of chemical reactions. When heated, it decomposes into hydrogen chloride and ammonia, which quickly react to reform ammonium chloride. Ammonium chloride or Sal Ammoniac (chemically ammonium chloride (NH4Cl); also salmiac, nushadir salt, zalmiak, sal armagnac, sal armoniac, salmiakki, salmiak and salt armoniack) is, in its pure form, a clear white water-soluble crystalline salt with a biting, slightly sour taste. ...


Sublimation purification

Simple sublimation apparatus. Water, usually cold, is circulated in cold finger to allow the desired compound to be deposited.1 Cooling water in 2 Cooling water out 3 Vacuum/gas line 4 Sublimation chamber 5 Sublimed compound 6 Crude material 7 External heating
Simple sublimation apparatus. Water, usually cold, is circulated in cold finger to allow the desired compound to be deposited.
1 Cooling water in 2 Cooling water out 3 Vacuum/gas line 4 Sublimation chamber 5 Sublimed compound 6 Crude material 7 External heating

Sublimation is a technique used by chemists to purify compounds. Typically a solid is placed in a vessel which is then heated under vacuum. Under this reduced pressure the solid volatilizes and condenses as a purified compound on a cooled surface, leaving the non-volatile residue impurities behind. This cooled surface often takes the form of a cold finger. Once heating ceases and the vacuum is released, the sublimed compound can be collected from the cooled surface. Usually this is done using a sublimation apparatus‎. Image File history File links Sublimation_apparatus. ... Image File history File links Sublimation_apparatus. ... A chemist pours from a round-bottom flask. ... A compound is an area of land that is surrounded by fences, walls, or barbed wire and is used for a particular purpose, especially an area containing buildings and where the entry and exit of people is controlled. ... Look up Vacuum in Wiktionary, the free dictionary. ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin in Canberra, Australia. ... Look up volatile in Wiktionary, the free dictionary. ... The ability of a liquid to evaporate quickly and at relatively low temperatures. ... Impurities are substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound. ... Cold fingers. ... Simple sublimation apparatus. ...


Uses

Frost-free freezers work by having a fan and air circulation inside the freezer. The sub-zero temperature combined with the air circulation that keeps the air arid significantly accelerates the sublimation process. This keeps freezer walls and shelves free of ice, although ice-cubes will continually sublimate. Sub-Zero is the name of two characters from the Mortal Kombat series. ... Fig. ... In general terms, the climate of a locale or region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life. ...


Dye sublimation is also often used in color printing on a variety of substrates, including paper. A small heater is used to vaporize the solid dye material, which then solidifies upon the paper. As this type of printer allows extremely fine control of the primary color ratios it is possible to obtain a good quality picture even with relatively low printer resolution, as compared to other printer types of similar resolution. Standard black and white laser printers are capable of printing on plain paper using a special "transfer toner" containing sublimation dyes which can then be permanently heat transferred to T-shirts, hats, mugs, metals, puzzles and other surfaces. The tone of this article is inappropriate for an encyclopedia. ... Color printing is the reproduction of an image or text in color (as opposed to simpler black and white or monochrome printing). ... Substrate is a term used in printing, mainly industrial printing, to describe the base material that images will be printed onto. ... A blank sheet of paper Paper is a commodity of thin material produced by the amalgamation of fibers, typically vegetable fibers composed of cellulose, which are subsequently held together by hydrogen bonding. ... The emission spectra of red, green, and blue phosphors that define the additive primary colors of a CRT color video display Primary colors, for humans, are sets of colors that can be combined to make a whole gamut of colors. ...


In alchemy, sublimation typically refers to the process by which a substance is heated to a vapor, then immediately collects as sediment on the upper portion and neck of the heating medium (typically a retort or alembic). It is one of the 12 core alchemical processes. For other uses, see Alchemy (disambiguation). ... A beautiful retort. ... An alembic is an alchemical still consisting of two retorts connected by a tube. ... Alchemical symbols, originally devised as part of the protoscience of alchemy, were used to denote some elements and some compounds until the 18th century. ...


In the Fast-Freeze, Deep-Etch technique, samples (for example, tissue samples) are rapidly frozen in liquid nitrogen and transferred to a vacuum device in which surface ice is sublimed. This effectively etches the sample surface, revealing the preserved 3D structure of the hydrated material. A rotary shadowed surface replica can then be obtained via electron microscopy. 2-dimensional renderings (ie. ... This article does not cite any references or sources. ...


Sublimation is also used to create freeze-dried substances, for example tea, soup or drugs in a process called lyophilization, which consists in freezing a solution or suspension and heating it very slowly under medium to high vacuum - specifically, a pressure lower than the vapor pressure of the solvent at its melting point. This can be well under the melting point of water if there are organic solvents or salts in the sample being freeze-dried. The resulting solid is usually much easier to dissolve or resuspend than one that is produced from a liquid system, and the low temperatures involved cause less damage to sensitive or reactive substances. For other meanings, see Drug (disambiguation). ... Freeze drying (also known as Lyophilization) is a dehydration process typically used to preserve a perishable material, or to make the material more convenient for transport. ... Look up Vacuum in Wiktionary, the free dictionary. ... In chemistry and physics, Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ... Solubility refers to the ability for a given substance, the solute, to dissolve in a solvent. ... It has been suggested that this article or section be merged into Mixture. ...

From To
Solid Liquid Gas Plasma
Solid Solid-Solid Transformation Melting Sublimation -
Liquid Freezing N/A Boiling/Evaporation -
Gas Deposition Condensation N/A Ionization
Plasma - - Recombination/Deionization N/A

  Results from FactBites:
 
Reference.com/Encyclopedia/Sublimation (chemistry) (0 words)
Sublimation of an element or compound is a transition from the solid to gas phase so rapidly that the liquid phase cannot be observed.
In alchemy, sublimation typically refers to the process by which a substance is heated to a vapor, then immediately collects as sediment on the upper portion and neck of the heating medium (typically a retort or alembic).
Sublimation is also used to create freeze-dried substances, for example tea, soup or drugs in a process called lyophilization, which consists in freezing a solution or suspension and heating it very slowly under medium to high vacuum - specifically, a pressure lower than the vapor pressure of the solvent at its melting point.
  More results at FactBites »

 
 

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