Question

Boron has two isotopes B10 andB11 persent in the ratio on 2:3 in a given sample.What will be the avarage atomic mass of boron?

Answer 1

Answer:

Let B-10 = x%

and B-11 = (100-x)%

average atomic mass = 10x + (100 - x)/100 = 10.80

10x + 11(100 - x) = 1080

10x + 1100 - 11x = 1080

x = 20

B-10 = 20% and B-11 = (100-20) = 80%

Thus, the percentage of a heavier isotope is 80%.