Francisco Antonio de Zela and Calcium oxide: Difference between pages
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'''Francisco Antonio De Zela y Arizaga''' is notable for sending forth the first libertarian outcry in the [[Peru]]vian city of [[Tacna]] on [[June 20]], [[1811]] in an attempt to start the independence of Peru. De Zela was supported by a large group of [[Creole peoples|criollos]], [[mestizos]] and [[Native Americans (Americas)|Indians]], among them the caciques [[José Rosa Ara]] and [[Miguel Copaja]]. |
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| Name = Calcium Oxide |
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| ImageFile = Calcium-oxide-3D-vdW.png |
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| ImageSize = 200px |
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| ImageName = Calcium oxide |
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| IUPACName = Calcium Oxide |
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| Section2 = {{Chembox Properties |
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| Formula = [[CaO]] |
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| MolarMass = 56.077 g/mol |
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| Appearance = White solid |
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| Density = 3350 kg/m³, solid |
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| Solubility = ''reacts'' |
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| MeltingPt = 2572 [[celsius|°C]] (2845 [[kelvin|K]]) |
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| BoilingPt = 2850 [[celsius|°C]] (3123 [[kelvin|K]]) |
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}} |
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| Section3 = {{Chembox Structure |
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| Structure = [[Cubic (crystal system)|Face-Centered Cubic]] |
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}} |
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}} |
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'''Calcium oxide''' ('''CaO'''), commonly known as '''burnt lime''', '''[[Lime (mineral)|lime]]''' or '''quicklime''', is a widely used [[chemical compound]]. It is a white, [[Caustic (substance)|caustic]] and [[alkali]]ne [[crystal]]line solid. As a commercial product, lime often also contains [[magnesium]] oxide, [[silicon]] oxide and smaller amounts of [[aluminium]] oxide and [[iron]] oxide. The name lime (native lime) refers to a very rare mineral of the CaO composition, too. |
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The rebellion of Tacna was in close contact with the Argentine revolution, initiated in Buenos Aires on [[May 25]], [[1810]]. The Argentines sent an army to the [[Charcas]] region ([[Bolivia]]), under the command of general [[Antonio González de Balcarce]] and the lawyer Castelli. They sent proclamations to various towns in southern Peru, inviting them to follow them in the revolution. The town of Tacna was the first under the direction of Don Francisco Antonio De Zela, occupying the quarters of the Spanish authorities that night. |
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[[Calcium]] [[oxide]] is usually made by the thermal decomposition of materials such as [[limestone]], that contain [[calcium carbonate]] (CaCO<sub>3</sub>; mineral name: [[calcite]]) in a [[lime kiln]]. This is accomplished by heating the material to above 825°[[celsius|C]],<ref name="merck">Merck Index of chemicals and Drugs , 9th ed. monograph 1650</ref> a process called [[calcination]] or ''lime-burning'', to liberate a molecule of [[carbon dioxide]] (CO<sub>2</sub>); leaving CaO. This process is reversible, since once the quicklime product has cooled, it immediately begins to absorb [[carbon dioxide]] from the air, until, after enough time, it is completely converted back to [[calcium carbonate]]. Calcination of limestone is one of the first chemical reactions discovered by man and was known in [[prehistory]].{{Fact|date=July 2008}} |
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Tragically, on the same day ([[June 20]]) the Argentine army was defeated by Spanish forces in [[Huaqui]], bordering [[Lake Titicaca]], and thus De Zela never received the needed support. This news created a morale problem for the De Zela's troops and as a result, they were defeated by the Spaniards. The main leaders of the rebellion were caught, among them De Zela, and they were led to Lima and condemned to 10 years in the military prison of [[Chagres]], [[Panama]], where De Zela died. |
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Up until the 20th century, quicklime was used as a disinfectant, usually in a 10% solution called milk of lime. However, it had the disadvantage of decomposing rapidly on exposure to air and moisture, and the burnt lime had to be fresh and unslaked.<ref name="sani">[http://books.google.com/books?id=RI2mGCexECAC A Complete Handbook for the Sanitary Troops of the U.S. Army and Navy (1917)]</ref> |
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His house, located on Zela Street #542, was named a Historical Monument on [[July 26]], [[1961]] and to this day continues to be one of the major tourist attractions of the city of Tacna. |
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==Usage== |
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[[June 20]] is a local holiday in city of [[Tacna]]. |
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As hydrated or [[slaked lime]], Ca(OH)<sub>2</sub> (mineral name: [[portlandite]]), it is used in [[mortar (masonry)|mortar]] and [[plaster]] to increase the rate of hardening as well as to improve adhesion{{Fact|date=October 2007}}. [[Hydrate]]d lime is very simple to make as lime is a basic [[anhydride]] and reacts vigorously with [[water]]. Lime is also used in [[glass]] production and its ability to react with silicates is also used in modern metal production industries ([[steel]], [[magnesium]], [[aluminium]] and others) to remove impurities as [[slag]]. |
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It is also used in water and sewage treatment to reduce [[acid]]ity, to soften, as a [[flocculation|flocculant]], and to remove [[phosphate]]s and other impurities; in [[paper]] making to dissolve [[lignin]], as a [[coagulant]], and in [[bleach]]ing; in agriculture to improve acidic [[soil]]s; and in [[pollution]] control, in gas scrubbers to [[sulfur|desulfur]]ize waste gases and to treat many liquid effluents. It has traditionally been used in the burial of bodies in open graves, to hide the smell of decomposition, as well as in forensic science, to reveal fingerprints. It is a [[refractory]] and a dehydrating agent and is used to purify [[citric acid]], [[glucose]], [[dye]]s and as a CO<sub>2</font> absorber. It is also used in [[pottery]], [[paint]]s and the food industry. Furthermore, quicklime is used in epidemics, plagues, and disasters to disintegrate bodies in order to help fight the spread of disease. CaO is a key ingredient in the ''[[nixtamalization]]'' process used to create [[maize|corn]] [[hominy]] and [[masa]] or tortilla dough. |
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[[Category:Peruvian people|De Zela,Francisco Antonio]] |
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A relatively inexpensive substance, CaO produces [[heat]] [[energy]] by the formation of the hydrate, as in the following equation:<ref name="patent">US Patent 3,955,554, '' Solar heating system.''</ref> |
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[[es:Francisco Antonio de Zela]] |
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::CaO + H<sub>2</sub>O ↔ Ca(OH)<sub>2</sub> + 63.7kJ/mol of CaO |
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The hydrate can be reconverted to calcium oxide by removing the water in the reversible equation. If the hydrated lime is heated to redness, the CaO will be regenerated to reverse the reaction. As it hydrates, an exothermic reaction results. One litre of water combines with approximately 3.1 kg of calcium oxide to give calcium hydroxide plus 3.54[[Joule|MJ]] of energy. This process can be used to provide a convenient portable source of heat, as for on-the-spot food warming in a [[self-heating can]]. |
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World lime annual production is around 130 million metric tons, with the USA and China the largest producers, each producing around 20 million metric tons.[http://indexmundi.com/en/commodities/minerals/lime/lime_t9.html] |
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==Use as Ancient Weapon== |
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Historian and philosopher [[David Hume]], in his history of [[England]], recounts how during early in the reign of [[Henry III]] the English Navy destroyed an invading French fleet, by blinding the enemy fleet with "quicklime," the old name for calcium oxide: |
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<i>D’Albiney employed a stratagem against them, which is said to have contributed to the victory: Having gained the wind of the French, he came down upon them with violence; and throwing in their faces a great quantity of quicklime, which he purposely carried on board, he so blinded them, that they were disabled from defending themselves.</i> |
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David Hume, History of England, Volume II. |
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==References== |
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<references/> |
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==External links== |
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* [http://minerals.usgs.gov/minerals/pubs/commodity/lime/limemyb01.pdf An authoritative discussion of lime and its uses (US context) by the US Geological Survey] |
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* [http://www.cheresources.com/quicklime.shtml Factors Affecting the Quality of Quicklime] |
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* [http://www.americanscientist.org/template/AssetDetail/assetid/17236/page/3 ''American Scientist''] (discussion of C<sup>14</sup> dating of mortar) |
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* [http://scifun.chem.wisc.edu/chemweek/lime/lime.html Chemical of the Week -- Lime] |
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* [http://www.carmeuse.com/page.asp?langue=EN&id=12 Lime production process presentation] |
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<!--Categories--> |
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[[Category:Oxides]] |
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[[Category:Calcium compounds]] |
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[[Category:Bases]] |
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[[Category:Limestone]] |
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[[Category:Alchemical substances]] |
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[[Category:Disinfectants]] |
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[[Category:Dehydrating agents]] |
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<!--Interwiki--> |
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[[ar:أكسيد كالسيوم]] |
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[[an:Calso]] |
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[[ay:Q'atawi]] |
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[[bg:Негасена вар]] |
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[[ca:Calç]] |
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[[cs:Oxid vápenatý]] |
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[[da:Kalciumoxid]] |
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[[de:Calciumoxid]] |
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[[et:Kaltsiumoksiid]] |
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[[es:Óxido de calcio]] |
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[[eo:Kalko]] |
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[[fa:کلسیم اکسید]] |
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[[fr:Oxyde de calcium]] |
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[[gl:Cal]] |
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[[it:Ossido di calcio]] |
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[[he:סיד]] |
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[[lv:Kalcija oksīds]] |
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[[lt:Kalcio oksidas]] |
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[[hu:Kalcium-oxid]] |
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[[nl:Calciumoxide]] |
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[[ja:酸化カルシウム]] |
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[[pl:Tlenek wapnia]] |
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[[pt:Cal]] |
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[[ro:Oxid de calciu]] |
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[[ru:Оксид кальция]] |
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[[sk:Oxid vápenatý]] |
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[[fi:Kalkki]] |
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[[sv:Kalciumoxid]] |
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[[vi:Ôxít canxi]] |
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[[tr:Kalsiyum oksit]] |
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[[uk:Оксид кальцію]] |
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[[zh:氧化钙]] |
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Revision as of 12:38, 12 October 2008
Calcium oxide (CaO), commonly known as burnt lime, lime or quicklime, is a widely used chemical compound. It is a white, caustic and alkaline crystalline solid. As a commercial product, lime often also contains magnesium oxide, silicon oxide and smaller amounts of aluminium oxide and iron oxide. The name lime (native lime) refers to a very rare mineral of the CaO composition, too.
Calcium oxide is usually made by the thermal decomposition of materials such as limestone, that contain calcium carbonate (CaCO3; mineral name: calcite) in a lime kiln. This is accomplished by heating the material to above 825°C,[1] a process called calcination or lime-burning, to liberate a molecule of carbon dioxide (CO2); leaving CaO. This process is reversible, since once the quicklime product has cooled, it immediately begins to absorb carbon dioxide from the air, until, after enough time, it is completely converted back to calcium carbonate. Calcination of limestone is one of the first chemical reactions discovered by man and was known in prehistory.[citation needed]
Up until the 20th century, quicklime was used as a disinfectant, usually in a 10% solution called milk of lime. However, it had the disadvantage of decomposing rapidly on exposure to air and moisture, and the burnt lime had to be fresh and unslaked.[2]
Usage
As hydrated or slaked lime, Ca(OH)2 (mineral name: portlandite), it is used in mortar and plaster to increase the rate of hardening as well as to improve adhesion[citation needed]. Hydrated lime is very simple to make as lime is a basic anhydride and reacts vigorously with water. Lime is also used in glass production and its ability to react with silicates is also used in modern metal production industries (steel, magnesium, aluminium and others) to remove impurities as slag.
It is also used in water and sewage treatment to reduce acidity, to soften, as a flocculant, and to remove phosphates and other impurities; in paper making to dissolve lignin, as a coagulant, and in bleaching; in agriculture to improve acidic soils; and in pollution control, in gas scrubbers to desulfurize waste gases and to treat many liquid effluents. It has traditionally been used in the burial of bodies in open graves, to hide the smell of decomposition, as well as in forensic science, to reveal fingerprints. It is a refractory and a dehydrating agent and is used to purify citric acid, glucose, dyes and as a CO2 absorber. It is also used in pottery, paints and the food industry. Furthermore, quicklime is used in epidemics, plagues, and disasters to disintegrate bodies in order to help fight the spread of disease. CaO is a key ingredient in the nixtamalization process used to create corn hominy and masa or tortilla dough.
A relatively inexpensive substance, CaO produces heat energy by the formation of the hydrate, as in the following equation:[3]
- CaO + H2O ↔ Ca(OH)2 + 63.7kJ/mol of CaO
The hydrate can be reconverted to calcium oxide by removing the water in the reversible equation. If the hydrated lime is heated to redness, the CaO will be regenerated to reverse the reaction. As it hydrates, an exothermic reaction results. One litre of water combines with approximately 3.1 kg of calcium oxide to give calcium hydroxide plus 3.54MJ of energy. This process can be used to provide a convenient portable source of heat, as for on-the-spot food warming in a self-heating can.
World lime annual production is around 130 million metric tons, with the USA and China the largest producers, each producing around 20 million metric tons.[1]
Use as Ancient Weapon
Historian and philosopher David Hume, in his history of England, recounts how during early in the reign of Henry III the English Navy destroyed an invading French fleet, by blinding the enemy fleet with "quicklime," the old name for calcium oxide:
D’Albiney employed a stratagem against them, which is said to have contributed to the victory: Having gained the wind of the French, he came down upon them with violence; and throwing in their faces a great quantity of quicklime, which he purposely carried on board, he so blinded them, that they were disabled from defending themselves.
David Hume, History of England, Volume II.
References
- ^ Merck Index of chemicals and Drugs , 9th ed. monograph 1650
- ^ A Complete Handbook for the Sanitary Troops of the U.S. Army and Navy (1917)
- ^ US Patent 3,955,554, Solar heating system.