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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 is this defined number of constituent particles (usually molecules, atoms, ions, or ion pairs—in general, entities) per mole and used as a normalization factor in relating the amount of substance, n(X), in a sample of a ...
These include the Boltzmann constant, which gives the correspondence of the dimension temperature to the dimension of energy per degree of freedom, and the Avogadro constant, which gives the correspondence of the dimension of amount of substance with the dimension of count of entities (the latter formally regarded in the SI as being dimensionless).
Historically, N 0 approximates the number of nucleons (protons or neutrons) in one gram of ordinary matter. The Avogadro constant (symbol N A = N 0 /mol) has numerical multiplier given by the Avogadro number with the unit reciprocal mole (mol −1). [2] The ratio n = N/N A is a measure of the amount of substance (with the unit mole). [2] [3] [4]
The number of discrete particles (such as molecules, atoms, ions, electrons, or any other atomic-scale entity) in a given sample of matter, divided by the Avogadro constant. The SI unit for amount of substance is the mole (mol). amphipathic (of a molecule) Composed of both hydrophilic and hydrophobic groups; e.g. wetting agents and membrane ...
which is a constant for a fixed pressure and a fixed temperature. An equivalent formulation of the ideal gas law can be written using Boltzmann constant k B, as =, where N is the number of particles in the gas, and the ratio of R over k B is equal to the Avogadro constant. In this form, for V/N is a constant, we have
For his work with gases a century prior, the physical constant that bears his name (the Avogadro constant) is the number of atoms per mole of elemental carbon-12 (6.022 × 10 23 mol −1). This specific number of gas particles, at standard temperature and pressure (ideal gas law) occupies 22.40 liters, which is referred to as the molar volume.
In chemistry, the amount of substance (symbol n) in a given sample of matter is defined as a ratio (n = N/N A) between the number of elementary entities (N) and the Avogadro constant (N A). The entities are usually molecules, atoms, ions, or ion pairs of a specified kind.
The ideal gas equation can be rearranged to give an expression for the molar volume of an ideal gas: = = Hence, for a given temperature and pressure, the molar volume is the same for all ideal gases and is based on the gas constant: R = 8.314 462 618 153 24 m 3 ⋅Pa⋅K −1 ⋅mol −1, or about 8.205 736 608 095 96 × 10 −5 m 3 ⋅atm⋅K ...