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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 ...
It is an informal holiday in honor of the unit among chemists. The date is derived from the Avogadro number, which is approximately 6.022 × 10 23. It starts at 6:02 a.m. and ends at 6:02 p.m. Alternatively, some chemists celebrate June 2 (06/02), June 22 (6/22), or 6 February (06.02), a reference to the 6.02 or 6.022 part of the constant.
The einstein (symbol E) is an obsolete unit with two conflicting definitions. It was originally defined as the energy in one mole of photons (6.022 × 10 23 photons). [1] [2] Because energy is inversely proportional to wavelength, the unit is frequency dependent.
1.6 × 10 −10 [23] ... 6.022 140 76 × 10 23 mol −1: 0 [49] = molar gas constant: 8.314 462 618 153 24 J⋅mol −1 ⋅K −1: 0 [50] = Faraday constant: 96 485 ...
In tribute to him, the ratio of the number of elementary entities (atoms, molecules, ions or other particles) in a substance to its amount of substance (the latter having the unit mole), 6.022 140 76 × 10 23 mol −1, is known as the Avogadro constant. This constant is denoted N A, and is one of the seven defining constants of the SI.
N A = 6.022 140 76 × 10 23 mol −1: u r (N A) = 0 [15] NAh: molar Planck constant N A h = 3.990 312 712... × 10 −10 J⋅Hz −1 ⋅mol −1: u r (N A h) = 0 [16] RK: von Klitzing constant: R K = 25 812.807 45... Ω: u r (R K) = 0 [17] Z0: characteristic impedance of vacuum: Z 0 = 376.730 313 412 (59) Ω: u r (Z 0) = 1.6 × 10 ...
Since 2019, the value of the Avogadro constant N A is defined to be exactly 6.022 140 76 × 10 23 mol −1. 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 concentration of pure osmium tetroxide (molar mass = 254.23 g/mol) is c(OsO 4) = 5.1 kg/L / 254.23 g/mol = 20.1 mol/L. A typical protein in bacteria, such as E. coli, may have about 60 copies, and the volume of a bacterium is about 10 −15 L. Thus, the number concentration C is C = 60 / (10 −15 L) = 6 × 10 16 L −1. The molar ...