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Elementary Entity
The mole (symbol mol) is a unit of measurement, the base unit in the International System of Units (SI) for ''amount of substance'', an SI base quantity proportional to the number of elementary entities of a substance. One mole is an aggregate of exactly elementary entities (approximately 602 sextillion or 602 billion times a trillion), which can be atoms, molecules, ions, ion pairs, or other particles. The number of particles in a mole is the Avogadro number (symbol ) and the numerical value of the ''Avogadro constant'' (symbol ) expressed in mol−1. The relationship between the mole, Avogadro number, and Avogadro constant can be expressed in the following equation:1\text = \frac = \frac The current SI value of the mole is based on the historical definition of the mole as the amount of substance that corresponds to the number of atoms in 12 grams of 12C, which made the molar mass of a compound in grams per mole, numerically equal to the average molecular mass or formu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amount Of Substance
In chemistry, the amount of substance (symbol ) in a given sample of matter is defined as a ratio () between the particle number, number of elementary entities () and the Avogadro constant (). The unit of amount of substance in the International System of Units is the Mole (unit), mole (symbol: mol), a SI base unit, base unit. p. 134 Since 2019, the mole has been defined such that the value of the Avogadro constant is exactly , defining a macroscopic unit convenient for use in laboratory-scale chemistry. The elementary entities are usually molecules, atoms, ions, or Ion pair, ion pairs of a specified kind. The particular chemical substance, substance sampled may be specified using a subscript or in parentheses, e.g., the amount of sodium chloride (NaCl) could be denoted as or . Sometimes, the amount of substance is referred to as the chemical amount or, informally, as the "number of moles" in a given sample of matter. The amount of substance in a sample can be calculated from mea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
