or combining weight
Quantity of an element that exactly reacts with (equals the combining value of) 1 g of hydrogen, 8 g of oxygen, or a corresponding amount of any other element.
An element's equivalent weight is its atomic weight divided by its valence . In general, for oxidation-reduction , including electrolysis , the equivalent weight is the weight associated with the loss or gain of 6.02 00D7; 10 23 electrons ( Avogadro's number ) or 96,500 coulombs of electric charge ; this is also the molecular weight divided by the number of electrons lost or gained. The equivalent weight of a substance with several valences differs depending on the number of electrons transferred in the given reaction. The number of equivalent weights of any substance dissolved in one litre of solution is called the solution's normality (N). See also stoichiometry .