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Gallium has two naturally occurring isotopes with the following masses and natural abundances: Isotope Mass ( amu ) Abundance (%) Ga−69 68.92558 60.108 Ga−71 70.92470 39.892. calculate the atomic mass of gallium

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The formula for determination of atomic mass given the mass of isotopes and relative abundance is:

Ar = ∑(mass * abundance) / 100
Ar = (68.92558 * 60.108 + 70.92470 * 39.892) / 100
Ar = 69.72306

The atomic mass of gallium is 69.72306 amu
User Hugues Fontenelle
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