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One mole is an aggregate of exactly 6.022 140 76 ... The term gram-molecule was formerly used to mean one mole of molecules, and gram-atom for one mole of atoms. [15]
The Avogadro constant, commonly denoted N A [1] or L, [2] is an SI defining constant with an exact value of 6.022 140 76 × 10 23 mol −1 (reciprocal moles). [3] [4] It defines the number of constituent particles in one mole, where the particles in question can be either molecules, atoms, ions, ion pairs, or any other elementary entities.
The molar mass of atoms of an element is given by the relative atomic mass of the element multiplied by the molar mass constant, M u ≈ 1.000 000 × 10 −3 kg/mol ≈ 1 g/mol. For normal samples from Earth with typical isotope composition, the atomic weight can be approximated by the standard atomic weight [ 2 ] or the conventional atomic weight.
Historically, the mole was defined as the amount of substance in 12 grams of the carbon-12 isotope.As a consequence, the mass of one mole of a chemical compound, in grams, is numerically equal (for all practical purposes) to the mass of one molecule or formula unit of the compound, in daltons, and the molar mass of an isotope in grams per mole is approximately equal to the mass number ...
This number was chosen so that if an element has an atomic mass of 1 u, a mole of atoms of that element has a mass close to one gram. Because of the definition of the unified atomic mass unit, each carbon-12 atom has an atomic mass of exactly 12 Da, and so a mole of carbon-12 atoms weighs exactly 0.012 kg. [65]
Mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 12 gram of carbon 12; its symbol is "mol". This was adopted by the CIPM (International Committee for Weights and Measures) in 1967, and in 1971, it was adopted by the 14th CGPM (General Conference on Weights and Measures) .
One mole of atoms contains an Avogadro number of atoms, so that the energy of one mole of atoms of a monatomic gas is =, where R is the gas constant. In an adiabatic process , monatomic gases have an idealised γ -factor ( C p / C v ) of 5/3, as opposed to 7/5 for ideal diatomic gases where rotation (but not vibration at room temperature) also ...
Chemistry – Physics: The Avogadro constant (6.022 140 76 × 10 23) is the number of constituents (e.g. atoms or molecules) in one mole of a substance, defined for convenience as expressing the order of magnitude separating the molecular from the macroscopic scale.