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спасибо!!! |
Alvick |
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Опять же, спасибо! |
SLS Участник |
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Tom1 Постоянный участник |
[Текст переведён с транслита] |
Esya Постоянный участник PA, USA |
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прошу прощения, но что-то у вас ответы не сходятся то Tom1: ету-то простую арифметику я понимаю то бишь, можно считать, что 1 Да - это 1 г/моль? |
himik Постоянный участник не родина |
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SLS Участник |
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Всем большое спасибо! |
gostya Постоянный участник |
Dalton, John (b. Sept. 6, 1766, Eaglesfield, Cumberland. Eng.- d. July 27, 1844, Manchester), British chemist and physicist who developed the atomic theory of matter and hence is known as one of the fathers of modern physical science Along with his other researches he also became interested in color blindness, a condition that he and his brother shared. Daltonism became a common term for color blindness. |
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Esya Постоянный участник PA, USA |
Виновата, не проверила... на практике, конечно, нет разницы, а вот на контрольной работе - может быть... стыыдно |
Esya Постоянный участник PA, USA |
http://www.bact.wisc.edu/Microtextbook/def...efinitions.html http://encyclopedia.thefreedictionary.com/...c%20mass%20unit |
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Esya Постоянный участник PA, USA |
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Esya Постоянный участник PA, USA |
the unit of mass used by chemists and physicists for measuring the masses of atoms and molecules. Early in the nineteenth century, scientists discovered that each chemical element is composed of atoms, and that each chemical compound is composed of molecules in which atoms are combined in a fixed way. No one knew then just how small atoms and molecules really are, but as long as the relative weights of the different atoms were known, the outcome of chemical reactions could be predicted. These relative masses were determined by careful study of various reactions. The general idea was that atoms of hydrogen, known to be the lightest element, should have a mass of 1 amu, and all the other atoms should have masses which are whole-number multiples of this (then unknown) mass of the hydrogen atom. For a long time, physicists and chemists disagreed on the details of this definition. In 1960 they agreed on the definition of the unified atomic mass unit as 1/12 the mass of the most common atoms of carbon, known as carbon-12 atoms. (Most elements are mixtures of atoms which have different masses because they contain different numbers of neutrons; these varieties are called isotopes.) Careful experiments have measured the size of this unit; the currently accepted value (1998) is 1.660 538 73 x 10-24 grams. (This number equals 1 divided by Avogadro's number; see mole.) In addition, 1 amu equals approximately 931.494 MeV (see electron volt). In biochemistry, the atomic mass unit is called the dalton (Da). *** dalton (Da or D) an alternate name for the unified atomic mass unit (u or amu). The dalton is often used in microbiology and biochemistry to state the masses of large organic molecules; these measurements are typically in kilodaltons (kDa). It seems necessary to have such a unit, since "kilo-amu" would be such a clumsy name. The SI accepts the dalton as an alternate name for the unified atomic mass unit and specifies Da as its proper symbol. The unit honors the English chemist John Dalton (1766-1844), who proposed the atomic theory of matter in 1803. http://www.unc.edu/~rowlett/units/dictD.html |
НАК - учитель химии IP-штамп: frqIpbAEL7zo2 гость |
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НАК - учитель химии IP-штамп: frqIpbAEL7zo2 гость |
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guest: илья IP-штамп: fr3vDOC7WjUE2 гость |
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Panaev Постоянный участник |
(guest: илья @ 19.03.2014 19:40) Так и будет 5000. |
guest: great IP-штамп: frj5GEfdEWR5M гость |
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