Question

The average atomic mass of copper is 63.55 amu. If the only two isotopes of copper have masses of 62.94 amu and 64.93 amu, what are the percentages of each?
Please show work!!!

Answer 1

Explanation:

Let relative ratio of one isotope (62.94 u) be X

Then, relative ratio of other isotope (64.93) will be (1 - X)

Now,

(62.94)x + (64.93)(1 - x) = 63.55

1.99x = 1.38

X = 0.69

Relative Abundance :

(62.94 u) isotope = 69 %

(64.93 u) isotope = 31 %