Answer:
Abundance of Ga 70.925 is 0.399 and percentage abundance of Ga 39.9%
Abundance of Ga 68.926 is 0.601 and percentage abundance is 60.1 %.
Explanation:
we know there are two naturally occurring isotopes of gallium Ga 68.926 and Ga 70.925.
First of all we will set the fraction for both isotopes
X for the isotopes having mass 70.925
1-x for isotopes having mass 68.926
The average atomic mass of Ga is 69.72.
we will use the following equation,
70.925 x + 68.926 (1-x) = 69.72
70.925 x + 68.926 - 68.926x = 69.72
70.925x- 68.926x = 69.72 - 68.926
1.99 x = 0.794
x= 0.794/ 1.99
x= 0.399
abundance of Ga 70.925 is 0.399, because we solve the fraction x.
0.399 × 100 = 39.9 %
39.9 % is percentage abundance of Ga 70.925
now we will calculate the abundance of Ga 68.926.
(1-x)
1 - 0.399 = 0.601
abundance of Ga 68.926 is 0.601 and percentage abundance is
0.601 × 100= 60.1 %