Equivalent Weight

Equivalent weight (also known as gram equivalent) is a term which has been used in several contexts in chemistry. In its most general usage, it is the mass of one equivalent, that is the mass of a given substance which will:

  • supply or react with one mole of hydrogen cations H+ in an acid–base reaction; or
  • supply or react with one mole of electrons e
    − in a redox reaction.

Equivalent weight has the dimensions and units of mass, unlike atomic weight, which is dimensionless. Equivalent weights were originally determined by experiment, but (insofar as they are still used) are now derived from molar masses. Additionally, the equivalent weight of a compound can be calculated by dividing the molecular weight by the number of positive or negative electrical charges that result from the dissolution of the compound.

Read more about Equivalent WeightHistory, Use in General Chemistry, Use in Volumetric Analysis, Use in Gravimetric Analysis, Use in Polymer Chemistry

Other articles related to "equivalent weight, weight, equivalent":

Faraday's Laws Of Electrolysis - Statements of The Laws
... material altered at an electrode is directly proportional to the element's equivalent weight ... The equivalent weight of a substance will be explained in the next paragraph ... For an element the equivalent weight is the quantity that combines with or replaces 1.00797 grams (g) of hydrogen or 7.9997 g of oxygen or, the weight of an element that ...
Equivalent Weight - Use in Polymer Chemistry
... In polymer chemistry, the equivalent weight of a reactive polymer is the mass of polymer which has one equivalent of reactivity (often, the mass of polymer which corresponds to ... is particularly important for ion-exchange polymers (also called ion-exchange resins) one equivalent of an ion-exchange polymer will exchange one mole of singly charged ions, but only half a mole of ... Nevertheless, given the decline in use of the term "equivalent weight" in the rest of chemistry, it has become more usual to express the reactivity of a polymer as the inverse of ...
Nafion - Nomenclature and Molecular Weight
... acid copolymer The molecular weight of Nafion is uncertain due to differences in processing and solution morphology ... Conventional methods of determining molecular weight such as light scattering and gel permeation chromatography are not applicable because Nafion is of course insoluble, although the molecular weight ... Instead, the equivalent weight (EW) and material thickness are used to describe most commercially available membranes ...

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