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  2. 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 ...

  3. Winkler titration - Wikipedia

    en.wikipedia.org/wiki/Winkler_titration

    1 mole of O 2 → 2 moles of MnO(OH) 2 → 2 mole of I 2 → 4 mole of S 2 O 2− 3. Therefore, after determining the number of moles of iodine produced, we can work out the number of moles of oxygen molecules present in the original water sample. The oxygen content is usually presented in milligrams per liter (mg/L).

  4. Stoichiometry - Wikipedia

    en.wikipedia.org/wiki/Stoichiometry

    The number of molecules per mole in a substance is given by the Avogadro constant, exactly 6.022 140 76 × 10 23 mol −1 since the 2019 revision of the SI. Thus, to calculate the stoichiometry by mass, the number of molecules required for each reactant is expressed in moles and multiplied by the molar mass of each to give the mass of each ...

  5. Oxygen transmission rate - Wikipedia

    en.wikipedia.org/wiki/Oxygen_transmission_rate

    Oxygen transmission rate (OTR) is the measurement of the amount of oxygen gas that passes through a substance over a given period. It is mostly carried out on non-porous materials, where the mode of transport is diffusion, but there are a growing number of applications where the transmission rate also depends on flow through apertures of some description.

  6. Oxygen balance - Wikipedia

    en.wikipedia.org/wiki/Oxygen_balance

    A molecule is said to have a positive oxygen balance if it contains more oxygen than is needed and a negative oxygen balance if it contains less oxygen than is needed. [2] An explosive with a negative oxygen balance will lead to incomplete combustion, which commonly produces carbon monoxide, which is a toxic gas. Explosives with negative or ...

  7. Respiratory quotient - Wikipedia

    en.wikipedia.org/wiki/Respiratory_quotient

    In this calculation, the CO 2 and O 2 must be given in the same units, and in quantities proportional to the number of molecules. Acceptable inputs would be either moles, or else volumes of gas at standard temperature and pressure. Many metabolized substances are compounds containing only the elements carbon, hydrogen, and oxygen.

  8. Molar volume - Wikipedia

    en.wikipedia.org/wiki/Molar_volume

    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.

  9. Glossary of chemistry terms - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_chemistry_terms

    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 ...