Ceramic From Chile
Ceramic From Chile
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Ceramic Ashtray from Chile $16.00 |
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Identifying the sources of Inka period ceramics from northern Chile: results of a neutron activation study [An article from: Journal of Archaeological Science] $7.95 This digital document is a journal article from Journal of Archaeological Science, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: To examine regional patterns of ceramic production and distribution during the era of Inka domination in northern Chil… |
Sodium (symbol Na, atomic number 11, and atomic weight 22,9898) is a chemical a soft metal, reactive and with a low melting point, and a relative density of 0,97 at 20ºC (68ºF). The element’s name comes from the English word soda, which is sometimes used to describe various sodium compounds. From the commercial point of view, sodium is the most important of all the alkaline metals. Sodium reacts quickly with water, and also with snow and ice, to produce sodium hydroxide and hydrogen. When recently cut metallic sodium is exposed to air, it loses its silvery appearance and acquires an opaque grey colour due to the formation of a sodium oxide coating. While sodium can react with ammonia to form sodium amide, it does react with halogens. Sodium and hydrogen react above 200ºC (390ºF) to form sodium hydride.
Sodium also reacts with various metallic halides to generate the metal and sodium chloride. Sodium doesn’t react with paraffinic hydrocarbons, but it forms addition compounds with naphthalene and other aromatic polycyclic compounds and with aryl alkenes. The reaction of sodium with alcohols is similar to the reaction of sodium with water, but slower. There are two general reactions with organic halides. One of them requires the condensation of two organic compounds, which form halogens when those are eliminated. The second type of reaction includes the replacement of halogen by sodium, to obtain a sodium organic compound. Sodium is found in nature only in the combined state. It occurs in the ocean and in salt lakes as sodium chloride, NaCl, and less often as sodium carbonate, Na2CO3, and sodium sulfate, Na2SO4. Sodium is prepared commercially by the electrolytic decomposition of fused sodium chloride. Sodium ranks seventh in order of abundance of the elements in Earth’s crust. It is a necessary constituent of plant and animal tissue.
Sodium is prepared commercially by the electrolytic decomposition of fused sodium chloride. It is a necessary constituent of plant and animal tissue. Sodium in its metallic form is very important in making esters and in the manufacture of organic compounds. Sodium is also a component of table salt, sodium chloride (NaCl) a very important compound found everywhere in the living environment. Its other uses are: to improve the structure of certain alloys; in soap, in combination with fatty acids, in sodium vapor lamps, to descale metals, to purify molten metals. Solid sodium carbonate is needed to make glass. The element is used in the manufacture of tetraethyl lead and as a cooling agent in nuclear reactors. Other important compounds of sodium include sodium carbonate, known as washing soda, and sodium bicarbonate, known as baking soda. Sodium hydroxide, known commercially as soda lye or caustic soda, is used in the manufacture of many important articles of immense importance. Sodium fluoride, NaF, is used as an antiseptic, as a poison for mice and roaches, and in ceramics. Sodium nitrate, known as Chile saltpeter, is used as a fertilizer. Sodium peroxide, Na2O2, is an important bleaching and oxidizing agent. Sodium thiosulfate, Na2S2O3 · 5H2O, known as hypo, is used in photography as a fixing agent.
Sodium is the most abundant element in the Earth’s crust and is found in nature only in the combined state ranking sixth or seventh in order of abundance of the elements and containing 2,83% of sodium in all its forms. It occurs in the ocean and in salt lakes as sodium chloride, NaCl, and less often as sodium carbonate, Na2CO3, and sodium sulfate, Na2SO4. Sodium is the second most abundant element after chlorine (as chloride ions) dissolved in seawater. The most important sodium salts found in nature are sodium chloride (halite or rock salt), sodium carbonate (trona or soda), sodium borate (borax), sodium nitrate and sodium sulfate. Sodium salts are found in seawater (1.05%), salty lakes, alkaline lakes and springs. A huge amount of this salt is extracted mainly from salt deposits by pumping water down bore holes to dissolve it and pumping up brine. The sun and many other stars shine with visible light in which the yellow component dominates and this is given out by sodium atoms in a high-energy state. Sodium’s powdered form is highly explosive in water and a poison combined and uncombined with many other elements. This chemical is not mobile in solid form, although it absorbs moisture very easily.
Sodium salts are important ingredients of many foodstuffs (for instance common salt) as besides imparting salty taste, it is necessary for humans to maintain the balance of the physical fluids system. Sodium is also required for nerve and muscle functioning. However, too much sodium can damage our kidneys and increases the chances of high blood pressure. The amount of sodium a person consumes each day varies from individual to individual and from culture to culture. Some people get as little as 2 g/day, some as much as 20 grams. Sodium is essential, but controversially surrounds the amount required. Contact of sodium with water, including perspiration causes the formation of sodium hydroxide fumes, which are highly irritating to skin, eyes, nose and throat. This may cause sneezing and coughing. Very severe exposures may result in difficult breathing, coughing and chemical bronchitis. Contact to the skin may cause itching, tingling, thermal and caustic burns and permanent damage. Its contact with eyes may result in permanent damage and loss of sight.
About the Author:
Dr.Badruddin Khan teaches chemistry in the University of Kashmir, Srinagar, india.His E.mail is:khanbudr@yahoo.co.in
Article Source: ArticlesBase.com – Environmental Impact and Health Effects of Sodium