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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 6.022 140 76 × 10 23 elementary entities (approximately 602 sextillion or 602 billion times a ...
The amount of substance is given as the number of moles in the sample. For most practical purposes, the numerical value of the molar mass in grams per mole is the same as that of the mean mass of one molecule or formula unit of the substance in daltons, as the mole was historically defined such that the molar mass constant was exactly 1 g/mol ...
mole: mol amount of substance "The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.022 140 76 × 10 23 elementary entities. This number is the fixed numerical value of the Avogadro constant, N A, when expressed in the unit mol −1 and is called the Avogadro number.
During that period, the molar mass of carbon-12 was thus exactly 12 g/mol, by definition. Since 2019, a mole of any substance has been redefined in the SI as the amount of that substance containing an exactly defined number of particles, 6.022 140 76 × 10 23. The molar mass of a compound in g/mol thus is equal to the mass of this number of ...
Approximate definition of a mole based on 12 grams of carbon-12. The Avogadro constant was historically derived from the old definition of the mole as the amount of substance in 12 grams of carbon-12 (12 C); or, equivalently, the number of daltons in a gram, where the dalton is defined as 1 / 12 of the mass of a 12 C atom. [9]
amount of substance: n, (ν) mole: mol: The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kg of 12 C. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specific groups of such particles.
2019 definition: [7]: 22 The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.022 140 76 × 10 23 elementary entities. This number is the fixed numerical value of the Avogadro constant , N A , when expressed in the unit mol −1 and is called the Avogadro number.
Change in volume with increasing ethanol fraction. The molar volume of a substance i is defined as its molar mass divided by its density ρ i 0: , = For an ideal mixture containing N components, the molar volume of the mixture is the weighted sum of the molar volumes of its individual components.