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  2. Yttrium - Wikipedia

    en.wikipedia.org/wiki/Yttrium

    [15] 89 Y has a mass number close to 90 and has 50 neutrons in its nucleus. At least 32 synthetic isotopes of yttrium have been observed, and these range in atomic mass number from 76 to 108. [ 30 ] The least stable of these is 109 Y with a half-life of 25 ms and the most stable is 88 Y with half-life 106.629 days. [ 31 ]

  3. List of refrigerants - Wikipedia

    en.wikipedia.org/wiki/List_of_refrigerants

    Molecular mass in atomic mass units Normal boiling points for pure substances, bubble and dew points for zeotropic blends, or normal boiling point and azeotropic temperature for the azeotropic blends, at 101,325 Pa (1 atmosphere) and in degrees Celsius

  4. Air conditioning - Wikipedia

    en.wikipedia.org/wiki/Air_conditioning

    The efficiency of air conditioners is often rated by the seasonal energy efficiency ratio (SEER), which is defined by the Air Conditioning, Heating and Refrigeration Institute in its 2008 standard AHRI 210/240, Performance Rating of Unitary Air-Conditioning and Air-Source Heat Pump Equipment. [61]

  5. List of physical constants - Wikipedia

    en.wikipedia.org/wiki/List_of_physical_constants

    For example, the atomic mass constant is exactly known when expressed using the dalton (its value is exactly 1 Da), but the kilogram is not exactly known when using these units, the opposite of when expressing the same quantities using the kilogram.

  6. Atomic mass - Wikipedia

    en.wikipedia.org/wiki/Atomic_mass

    The atomic mass (relative isotopic mass) is defined as the mass of a single atom, which can only be one isotope (nuclide) at a time, and is not an abundance-weighted average, as in the case of relative atomic mass/atomic weight. The atomic mass or relative isotopic mass of each isotope and nuclide of a chemical element is, therefore, a number ...

  7. Freon - Wikipedia

    en.wikipedia.org/wiki/Freon

    A can of 1,1,1,2-Tetrafluoroethane (Freon 134a) used for recharging vehicle air conditioning. Freon (/ ...

  8. Mass number - Wikipedia

    en.wikipedia.org/wiki/Mass_number

    The mass number should also not be confused with the standard atomic weight (also called atomic weight) of an element, which is the ratio of the average atomic mass of the different isotopes of that element (weighted by abundance) to the atomic mass constant. [9] The atomic weight is a mass ratio, while the mass number is a counted number (and ...

  9. List of common physics notations - Wikipedia

    en.wikipedia.org/wiki/List_of_common_physics...

    atomic mass number: unitless acceleration: meter per second squared (m/s 2) magnetic flux density also called the magnetic field density or magnetic induction tesla (T), or equivalently, weber per square meter (Wb/m 2) capacitance: farad (F) heat capacity: joule per kelvin (J⋅K −1)