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  2. Mass fraction (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Mass_fraction_(chemistry)

    In chemistry, the mass fraction of a substance within a mixture is the ratio (alternatively denoted ) of the mass of that substance to the total mass of the mixture. [1] Expressed as a formula, the mass fraction is:

  3. 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 ...

  4. Mass spectrum - Wikipedia

    en.wikipedia.org/wiki/Mass_spectrum

    A mass spectrum is a histogram plot of intensity vs. mass-to-charge ratio (m/z) in a chemical sample, [1] usually acquired using an instrument called a mass spectrometer. Not all mass spectra of a given substance are the same; for example, some mass spectrometers break the analyte molecules into fragments ; others observe the intact molecular ...

  5. Empirical formula - Wikipedia

    en.wikipedia.org/wiki/Empirical_formula

    In chemistry, the empirical formula of a chemical compound is the simplest whole number ratio of atoms present in a compound. [1] A simple example of this concept is that the empirical formula of sulfur monoxide, or SO, is simply SO, as is the empirical formula of disulfur dioxide, S 2 O 2.

  6. Molar mass - Wikipedia

    en.wikipedia.org/wiki/Molar_mass

    In chemistry, the molar mass (M) (sometimes called molecular weight or formula weight, but see related quantities for usage) of a chemical compound is defined as the ratio between the mass and the amount of substance (measured in moles) of any sample of the compound. [1] The molar mass is a bulk, not molecular, property of a substance.

  7. 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.

  8. Atomic ratio - Wikipedia

    en.wikipedia.org/wiki/Atomic_ratio

    The atomic ratio is a measure of the ratio of atoms of one kind (i) to another kind (j). A closely related concept is the atomic percent (or at.% ), which gives the percentage of one kind of atom relative to the total number of atoms. [ 1 ]

  9. Branching fraction - Wikipedia

    en.wikipedia.org/wiki/Branching_fraction

    In particle physics and nuclear physics, the branching fraction (or branching ratio) for a decay is the fraction of particles which decay by an individual decay mode or with respect to the total number of particles which decay.