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  2. List of physical quantities - Wikipedia

    en.wikipedia.org/wiki/List_of_physical_quantities

    kg/kg 1: intensive (Mass) Density (or volume density) ρ: Mass per unit volume kg/m 3: L −3 M: intensive Mean lifetime: τ: Average time for a particle of a substance to decay s T: intensive Molar concentration: C: Amount of substance per unit volume mol⋅m −3: L −3 N: intensive Molar energy: J/mol: Amount of energy present in a system ...

  3. Quantities, Units and Symbols in Physical Chemistry

    en.wikipedia.org/wiki/Quantities,_Units_and...

    Quantities, Units and Symbols in Physical Chemistry, also known as the Green Book, is a compilation of terms and symbols widely used in the field of physical chemistry. It also includes a table of physical constants , tables listing the properties of elementary particles , chemical elements , and nuclides , and information about conversion ...

  4. List of physical constants - Wikipedia

    en.wikipedia.org/wiki/List_of_physical_constants

    The constants listed here are known values of physical constants expressed in SI units; that is, physical quantities that are generally believed to be universal in nature and thus are independent of the unit system in which they are measured.

  5. Orders of magnitude (mass) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(mass)

    1.6 × 10 33 kg Pleiades star cluster (800 M ☉) [159] 10 34: 10 35 ~10 35 kg Typical globular cluster in the Milky Way (overall range: 3 × 10 3 to 4 × 10 6 M ☉) [160] 2 × 10 35 kg Low end of mass range for giant molecular clouds (1 × 10 5 to 1 × 10 7 M ☉) [161] [162] 7.3 × 10 35 kg Jeans mass of a giant molecular cloud at 100 K and ...

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

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

    2 He helium-4; Hoffer et al. 0.19085 g/cm 3 (from 20.9730 cm 3 /mole; hcp crystal melting to He-II superfluid at 0 K, 25.00 atm) : 0.19083 g/cm 3 (from 20.9749 cm 3 /mole; at local min. density, hcp melting to He-II: 0.884 K, 25.00 atm)

  7. SI base unit - Wikipedia

    en.wikipedia.org/wiki/SI_base_unit

    kg mass "The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10 −34 when expressed in the unit J s, which is equal to kg m 2 s −1, where the metre and the second are defined in terms of c and ∆ν Cs." [1]

  8. List of metric units - Wikipedia

    en.wikipedia.org/wiki/List_of_metric_units

    The svedberg (S or Sv) is a unit of time used in chemistry equal to one hundred femtoseconds (100 fs). The shake is a unit of time used in nuclear physics equal to ten nanoseconds (10 ns). The sigma is a unit of time equal to one microsecond (1 μs). The jiffy is sometimes used to mean a unit of time of 10 ms. [dubious – discuss]

  9. 2019 revision of the SI - Wikipedia

    en.wikipedia.org/wiki/2019_revision_of_the_SI

    The SI system after the 2019 definition: Base units as defined in terms of physical constants and other base units. Here, means is used in the definition of . The SI system after 1983, but before the 2019 redefinition: Base unit definitions in terms of other base units (for example, the metre is defined as the distance travelled by light in a specific fraction of a second), with the constants ...