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  2. Mass (mass spectrometry) - Wikipedia

    en.wikipedia.org/wiki/Mass_(mass_spectrometry)

    The accurate mass (more appropriately, the measured accurate mass [9]) is an experimentally determined mass that allows the elemental composition to be determined. [10] For molecules with mass below 200 Da , 5 ppm accuracy is often sufficient to uniquely determine the elemental composition.

  3. Mass versus weight - Wikipedia

    en.wikipedia.org/wiki/Mass_versus_weight

    In scientific contexts, mass is the amount of "matter" in an object (though "matter" may be difficult to define), but weight is the force exerted on an object's matter by gravity. [1] At the Earth 's surface, an object whose mass is exactly one kilogram weighs approximately 9.81 newtons , the product of its mass and the gravitational field ...

  4. Lever rule - Wikipedia

    en.wikipedia.org/wiki/Lever_rule

    In chemistry, the lever rule is a formula used to determine the mole fraction (x i) or the mass fraction (w i) of each phase of a binary equilibrium phase diagram.It can be used to determine the fraction of liquid and solid phases for a given binary composition and temperature that is between the liquidus and solidus line.

  5. International Prototype of the Kilogram - Wikipedia

    en.wikipedia.org/wiki/International_prototype_of...

    The above are all relative measurements; no historical mass-measurement data is available to determine which of the prototypes has been most stable relative to an invariant of nature. There is the distinct possibility that all the prototypes gained mass over 100 years and that K21, K35, K40, and the IPK simply gained less than the others.

  6. Elemental analysis - Wikipedia

    en.wikipedia.org/wiki/Elemental_analysis

    [citation needed] This information is important to help determine the structure of an unknown compound, as well as to help ascertain the structure and purity of a synthesized compound. In present-day organic chemistry, spectroscopic techniques ( NMR , both 1 H and 13 C), mass spectrometry and chromatographic procedures have replaced EA as the ...

  7. Scientists Have Determined How to Travel Back in Time ... - AOL

    www.aol.com/scientists-determined-travel-back...

    A recent study claims to have calculated a potential method of time travel. It involves a highly theoretical object called a “ring wormhole,” which is a type of wormhole that connects two ...

  8. Gravimetric analysis - Wikipedia

    en.wikipedia.org/wiki/Gravimetric_analysis

    Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte (the ion being analyzed) based on its mass. The principle of this type of analysis is that once an ion's mass has been determined as a unique compound, that known measurement can then be used to determine the same analyte's mass in a mixture, as long as the relative ...

  9. Annus mirabilis papers - Wikipedia

    en.wikipedia.org/wiki/Annus_Mirabilis_papers

    The mass of a body is a measure of its energy-content; if the energy changes by L, the mass changes in the same sense by L/(9 × 10 20), the energy being measured in ergs, and the mass in grammes. If the theory corresponds to the facts, radiation conveys inertia between the emitting and absorbing bodies.