Answer:
The relative atomic mass of the sample of Germanium is 72.89 u
Step-by-step explanation:
For a sample of germanium we have the following compositions:
m70Ge = 70 u
%70Ge = 22.6%
m72Ge = 72 u
%72Ge = 25.45%
m74Ge = 74 u
%74Ge = 36.73%
m76Ge = 76 u
%76Ge = 15.22%
To calculate the atomic mass of Germanium we must add all the atomic masses of its isotopes multiplied by its percentage of abundance and all this divided by 100, in this way:
mGe = [(m70Gex%70Ge)+(m72Gex%72Ge)+(m74Gex%74Ge)+(m76Gex%76Ge)]/100
replacing values:
mGe = [(70x22.6)+(72x25.45)+(74x36.73)+(76x15.22)]/100 = 72.89 u