From Wikipedia,
the free encyclopedia.
Equivalent weight is the
atomic weight of an
element or
radical divided by the
valence it assumes in a
chemical compound.
For example,
hydrogen, with atomic weight
1.008 and valence 1, has an
equivalent weight of 1.008.
Oxygen assumes a valence of 2
and has an atomic weight of
15.9994, so it has an equivalent
weight of 7.9997.
Elements may assume different
equivalent weights in different
compounds. For example,
iron (atomic weight 55.845)
assumes equivalent weight 27.9225
if it is valence 2 in the compound
(ferrous); or 18.615 if it is
valence 3 (ferric).
The equivalent weight can also
be computed for other than pure
elements. For example, the
carbonate radical (CO3)
has a formula (atomic) weight of
76.0083 and assumes valence 2 in
compounds, so its equivalent
weight is 38.00415.
