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  2. Chromate and dichromate - Wikipedia

    en.wikipedia.org/wiki/Chromate_and_dichromate

    The hydrogen chromate ion may be protonated, with the formation of molecular chromic acid, H 2 CrO 4, but the pK a for the equilibrium H 2 CrO 4 ⇌ HCrO − 4 + H + is not well characterized. Reported values vary between about −0.8 and 1.6. [4] The dichromate ion is a somewhat weaker base than the chromate ion: [5]

  3. Dihydrogen cation - Wikipedia

    en.wikipedia.org/wiki/Dihydrogen_cation

    The dihydrogen cation or hydrogen molecular ion is a cation (positive ion) with formula +. It consists of two hydrogen nuclei , each sharing a single electron. It is the simplest molecular ion. The ion can be formed from the ionization of a neutral hydrogen molecule by

  4. 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 ...

  5. Hydrogen ion - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_ion

    The concentration of hydrogen ions and pH are inversely proportional; in an aqueous solution, an increased concentration of hydrogen ions yields a low pH, and subsequently, an acidic product. By definition, an acid is an ion or molecule that can donate a proton, and when introduced to a solution it will react with water molecules (H 2 O) to ...

  6. Chromium compounds - Wikipedia

    en.wikipedia.org/wiki/Chromium_compounds

    The Pourbaix diagram for chromium in pure water, perchloric acid, or sodium hydroxide [1] [2] Chromium compounds are compounds containing the element chromium (Cr). Chromium is a member of group 6 of the transition metals. The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium ...

  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 ≈ 1.000 000 × 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. Mass-to-charge ratio - Wikipedia

    en.wikipedia.org/wiki/Mass-to-charge_ratio

    When charged particles move in electric and magnetic fields the following two laws apply: Lorentz force law: = (+),; Newton's second law of motion: = =; where F is the force applied to the ion, m is the mass of the particle, a is the acceleration, Q is the electric charge, E is the electric field, and v × B is the cross product of the ion's velocity and the magnetic flux density.

  9. Densities of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Densities_of_the_elements...

    0.17308 g/cm 3 (from 23.1256 cm 3 /mole; at local min. density, from hcp melt at 0.699 K, 24.993 atm) 0.17443 g/cm 3 (from 22.947 cm 3 /mole; He-II at triple point hcp−bcc−He-II: 1.463 K, 26.036 atm) 0.1807 g/cm 3 (from 22.150 cm 3 /mole; He-I at triple point hcp−bcc−He-I: 1.772 K, 30.016 atm) 3 Li lithium; use: 0.512 g/cm 3: CR2 (at m ...