Методическая разработка по английскому языку для студентов факультета химии и химической технологии " Simple Chemistry" Алматы 2017
жүктеу/скачать 422,31 Kb.
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мет. разработка по химии
BismuthBismuth is a metallic chemical element. It is brittle, has a high luster, and is greyish-white with a red or pink tinge. Bismuth is relatively inactive chemically at normal temperatures, but when bismuth is heated in air it burns. It is soluble in strong acids such as aqua regia and nitric acid. Bismuth combines directly with fluorine and the other halogen elements, as well as with sulfur and selenium. Bismuth has some unusual physical properties. It is one of only two elements that expands upon solidifying. Except for mercury, bismuth is the poorest heat conductor of all the metals. Bismuth’s electrical resistance increases in a magnetic field. This property is greater in bismuth than in other metals. Bismuth occurs in nature as a free metal, but is more common in ores that contain other elements. The principal ores are bismite (Bi2O3) and bismuthinite (Bi2S3). Most bismuth is recovered as a by-product from the mining of lead, copper, tin and zinc. The leading producers of bismuth are Mexico, China, Peru, Australia and Japan. Bismuth in impure form was known to the alchemists of the Middle Ages. It was first identified as a separate element in 1753 by Claude Franois Geoffroy, a French chemist. Bismuth is used chiefly to make low-melting point alloys. These alloys are used in electrical fuses and water- heater safety valves, and also in fire detectors and automatic sprinkler systems. Bismuth is sometimes added to alloys of iron, steel and aluminum to improve the machining qualities of these alloys. Other uses of bismuth are in drugs, cosmetics, glass and ceramics. The symbol of bismuth is Bi. Its atomic number is 83. Its atomic weight is 208.9804. Bismuth has melting point of 520.34 F. (271.3 C.). Bismuth has boiling point of 2,840 F. (1,560 C.). The specific gravity of bismuth is 9.8. It belongs to Group VA of the Periodic Table and may have a valence of +3 or +5. Several radioactive isotopes of bismuth are known. Only one isotope, Bi-209, is stable. Vocabulary notes bismuth висмут a luster блеск a high luster сильный блеск aqua regia царская водка fluorine фтор sulfur сера selenium селен as well as также to expand расширяться, увеличиваться upon solidifying при затвердевании except for за исключением mercury ртуть a heat conductor теплопроводник electrical resistance электрическое сопротивление to increase увеличиваться a magnetic field магнитное поле bismite висмутовая охра bismuthinite бисмутинит to recover получать, восстанавливать a by-product побочный продукт impure form не чистая форма the Middle Ages средневековье a separate element отдельный элемент low-melting point alloys легкоплавкие сплавы electrical fuses электрические предохранители water- heater safety valves предохранительные клапаны водонагревателей fire detectors пожарные извещатели automatic sprinkler systems автоматические противопожарные системы steel сталь to improve улучшать machining qualities качество обработки на станке жүктеу/скачать 422,31 Kb. Достарыңызбен бөлісу:
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