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  2. Nitrogen - Wikipedia

    en.wikipedia.org/wiki/Nitrogen

    14 N is one of the five stable odd–odd nuclides (a nuclide having an odd number of protons and neutrons); the other four are 2 H, 6 Li, 10 B, and 180m Ta. [ 34 ] The relative abundance of 14 N and 15 N is practically constant in the atmosphere but can vary elsewhere, due to natural isotopic fractionation from biological redox reactions and ...

  3. Amount of substance - Wikipedia

    en.wikipedia.org/wiki/Amount_of_substance

    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 ...

  4. Mole (unit) - Wikipedia

    en.wikipedia.org/wiki/Mole_(unit)

    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]

  5. Number density - Wikipedia

    en.wikipedia.org/wiki/Number_density

    For example, replacing m with q (total charge) and m 0 with q 0 (charge of each object) in the above equation will lead to a correct expression for charge. The number density of solute molecules in a solvent is sometimes called concentration, although usually concentration is expressed as a number of moles per unit volume (and thus called molar ...

  6. Stoichiometry - Wikipedia

    en.wikipedia.org/wiki/Stoichiometry

    The molar ratio allows for conversion between moles of one substance and moles of another. For example, in the reaction 2 CH 3 OH + 3 O 2 → 2 CO 2 + 4 H 2 O. the amount of water that will be produced by the combustion of 0.27 moles of CH 3 OH is obtained using the molar ratio between CH 3 OH and H 2 O of 2 to 4.

  7. Charge number - Wikipedia

    en.wikipedia.org/wiki/Charge_number

    The charge number equals the electric charge (q, in coulombs) divided by the elementary charge: z = q/e. Atomic numbers (Z) are a special case of charge numbers, referring to the charge number of an atomic nucleus, as opposed to the net charge of an atom or ion. The charge numbers for ions (and also subatomic particles) are written in ...

  8. Avogadro constant - Wikipedia

    en.wikipedia.org/wiki/Avogadro_constant

    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 ...

  9. Molar concentration - Wikipedia

    en.wikipedia.org/wiki/Molar_concentration

    Here, is the amount of the solute in moles, [4] is the number of constituent particles present in volume (in litres) of the solution, and is the Avogadro constant, since 2019 defined as exactly 6.022 140 76 × 10 23 mol −1.