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In Chemistry / High School | 2014-10-06

Determine the average atomic mass of helium, which has two isotopes with atomic masses of 4.0026 amu and 3.0160 amu. The relative abundance of the isotopes is 99.9999% and 0.0001%, respectively.

Asked by Annon997

Answer (2)

m a ​ = 4.0026 ⋅ 99.9999% + 3.0160 ⋅ 0.0001% = = 4.0025959974 + 0.000003016 = = 4 , 0025990134 [ am u ]
The average atomic mass of helium is 4,0025990134 amu.

Answered by naǫ | 2024-06-10

The average atomic mass of helium, calculated using its isotopes' masses and their abundances, is approximately 4.0026 amu. This value reflects the prevalence of helium-4 compared to helium-3. The calculation method involves multiplying each isotope's mass by its relative abundance and summing the results.
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Answered by naǫ | 2024-10-22