Answer to Question #221703 in General Chemistry for Kate

Question

Gallium has two naturally occurring isotopes with mass 69 and 71 respectively. What is the peecentage abundance of both isotopes if their relative atomic mass is 70.59?

Answer 1

solution

Let the percentage of the isotope 71 Gallium be =y%

The percentage of the isotope 69Ga is =(100−y) %

Therefore, we write the mass balance equation

100×69.72 = y×71+(100−y) ×69

6972 = 71y+6900−69y

2y=6972−6900=72

y=36

The percentage of the isotope is =36%