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Chemistry Practice Problems: Atomic Mass Calculations II

[Miss part one? Check out Atomic Mass Calculations I.]

[Download the accompanying PDF worksheet.]

1. Magnesium has three naturally occurring isotopes, 24Mg (78.99%, 23.9850 amu), 25Mg (10.00%, 24.9858 amu), and 26Mg.  Determine the percent abundance and isotopic mass of 26Mg.

2. Boron has two naturally occurring isotopes.  Find the percent abundances of 10B and 11B given the isotopic mass of 10B = 10.0129 amu and the isotopic mass of 11B = 11.0093 amu.

3. Chlorine has two naturally occurring isotopes, 35Cl (34.9689 amu) and 37Cl (36.9659 amu).  If chlorine has an average atomic mass of 35.4527 amu, what is the percent abundance of each isotope?



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