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  2. Mole (unit) - Wikipedia

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

    The mole (symbol mol) is a unit of measurement, the base unit in the International System of Units (SI) for amount of substance, a quantity proportional to the number of elementary entities of a substance. One mole contains exactly 6.022 140 76 × 1023 elementary entities (approximately 602 sextillion or 602 billion times a trillion), which can ...

  3. Oxygen - Wikipedia

    en.wikipedia.org/wiki/Oxygen

    Oxygen is a chemical element; it has symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is the most abundant element in Earth's crust, and after hydrogen and helium, it ...

  4. Electrolysis of water - Wikipedia

    en.wikipedia.org/wiki/Electrolysis_of_water

    Electrolysis of water is using electricity to split water into oxygen (O. 2) and hydrogen (H. 2) gas by electrolysis. Hydrogen gas released in this way can be used as hydrogen fuel, but must be kept apart from the oxygen as the mixture would be extremely explosive. Separately pressurised into convenient 'tanks' or 'gas bottles', hydrogen can be ...

  5. Stoichiometry - Wikipedia

    en.wikipedia.org/wiki/Stoichiometry

    There is a 1:1 molar ratio of NH 3 to NO 2 in the above balanced combustion reaction, so 5.871 mol of NO 2 will be formed. We will employ the ideal gas law to solve for the volume at 0 °C (273.15 K) and 1 atmosphere using the gas law constant of R = 0.08206 L·atm·K −1 ·mol1:

  6. Hydrogen bond - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_bond

    A symmetric hydrogen bond is a special type of hydrogen bond in which the proton is spaced exactly halfway between two identical atoms. The strength of the bond to each of those atoms is equal. It is an example of a three-center four-electron bond. This type of bond is much stronger than a "normal" hydrogen bond.

  7. Molar mass - Wikipedia

    en.wikipedia.org/wiki/Molar_mass

    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 × 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.

  8. Equivalent weight - Wikipedia

    en.wikipedia.org/wiki/Equivalent_weight

    The equivalent weight of an element is the mass which combines with or displaces 1.008 gram of hydrogen or 8.0 grams of oxygen or 35.5 grams of chlorine. The equivalent weight of an element is the mass of a mole of the element divided by the element's usual valence. That is, in grams, the atomic weight of the element divided by the usual ...

  9. Amount of substance - Wikipedia

    en.wikipedia.org/wiki/Amount_of_substance

    The unit of amount of substance in the International System of Units is the mole (symbol: mol), a base unit. [1] Since 2019, the value of the Avogadro constant NA is defined to be exactly 6.022 140 76 × 1023 mol1. Sometimes, the amount of substance is referred to as the chemical amount or, informally, as the " number of moles " in a given ...