h = 1 isotope is used as relative scale to find atomic mass.
which isotope is used as relative scale to find atomic mass?
h = 1
the molar mass constant was unusual (but not unique) among physical constants by having an exactly defined value rather than being measured experimentally. from the old definition of the mole, the molar mass of carbon 12 was exactly 12 g/mol. from the definition of relative atomic mass, the relative atomic mass of carbon 12, that is the atomic weight of a sample of pure carbon 12, is exactly 12. the molar mass constant was thus given by









































formula_1









































the speed of light is another example of a physical constant whose value is fixed by the definitions of the international system of units (si).
molar mass constant
in 1979, as a compromise, the term "relative atomic mass" was introduced as a secondary synonym for atomic weight. twenty years later the primacy of these synonyms was reversed, and the term "relative atomic mass" is now the preferred term.









































however, the term ""standard" atomic weights" (referring to the standardized expectation atomic weights of differing samples) has not been changed, because simple replacement of "atomic weight" with "relative atomic mass" would have resulted in the term "standard relative atomic mass."









































section::::see also.









































bullet::::- atomic number









































bullet::::- atomic mass unit









































bullet::::- isotope









































bullet::::- isotope geochemistry









































bullet::::- molecular mass









































bullet::::- jean stas
atomic mass