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  2. Hydrogen - Wikipedia

    en.wikipedia.org/wiki/Hydrogen

    Hydrogen is a chemical element; it has symbol H and atomic number 1. It is the lightest element and, at standard conditions, is a gas of diatomic molecules with the formula H 2, sometimes called dihydrogen, [11] hydrogen gas, molecular hydrogen, or simply hydrogen. It is colorless, odorless, [12] non-toxic, and highly combustible.

  3. Standard enthalpy of formation - Wikipedia

    en.wikipedia.org/wiki/Standard_enthalpy_of_formation

    Monatomic hydrogen Gas H 218 Hydrogen: Gas H 2: 0 Water: Gas H 2 O −241.818 Water: Liquid H 2 O −285.8 Hydrogen ion: Aqueous H + 0 Hydroxide ion: Aqueous OH −: −230 Hydrogen peroxide: Liquid H 2 O 2: −187.8 Phosphoric acid: Liquid H 3 PO 4: −1288 Hydrogen cyanide: Gas HCN 130.5 Hydrogen bromide: Liquid HBr −36.3 Hydrogen chloride ...

  4. Liquid hydrogen - Wikipedia

    en.wikipedia.org/wiki/Liquid_hydrogen

    Liquid hydrogen (H 2 (l)) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H 2 form. [4] To exist as a liquid, H 2 must be cooled below its critical point of 33 K. However, for it to be in a fully liquid state at atmospheric pressure, H 2 needs to be cooled to 20.28 K (−252.87 °C; −423.17 °F). [5]

  5. Hydrogen atom - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_atom

    Depiction of a hydrogen atom showing the diameter as about twice the Bohr model radius. (Image not to scale) A hydrogen atom is an atom of the chemical element hydrogen.The electrically neutral hydrogen atom contains a single positively charged proton in the nucleus, and a single negatively charged electron bound to the nucleus by the Coulomb force.

  6. Vapour density - Wikipedia

    en.wikipedia.org/wiki/Vapour_density

    Vapour density is the density of a vapour in relation to that of hydrogen. It may be defined as mass of a certain volume of a substance divided by mass of same volume of hydrogen. vapour density = mass of n molecules of gas / mass of n molecules of hydrogen gas . vapour density = molar mass of gas / molar mass of H 2

  7. Haber process - Wikipedia

    en.wikipedia.org/wiki/Haber_process

    Fritz Haber, 1918. The Haber process, [1] also called the Haber–Bosch process, is the main industrial procedure for the production of ammonia. [2] [3] It converts atmospheric nitrogen (N 2) to ammonia (NH 3) by a reaction with hydrogen (H 2) using finely divided iron metal as a catalyst:

  8. Chemical formula - Wikipedia

    en.wikipedia.org/wiki/Chemical_formula

    The Hill system (or Hill notation) is a system of writing empirical chemical formulae, molecular chemical formulae and components of a condensed formula such that the number of carbon atoms in a molecule is indicated first, the number of hydrogen atoms next, and then the number of all other chemical elements subsequently, in alphabetical order ...

  9. Equivalent weight - Wikipedia

    en.wikipedia.org/wiki/Equivalent_weight

    The term “equivalent weight” had a distinct meaning in gravimetric analysis: it meant the mass of precipitate produced from one gram of analyte (the species of interest). The different definitions came from the practice of quoting gravimetric results as mass fractions of the analyte, often expressed as a percentage. A related term was the ...