Question

Average atomic mass of boron is 10.8. Find
the percentage abundance of isotopes of
boron with atomic masses 10 and
11 respectively.
​

Answer 1

Given, 2 isotopes= 10b &11b

average atomic mass 10.8u

let %abundance of b-10 is u%

%abundance of b-11 is (100-u)

10.8=u×10+(100-u)^11 / 100

10.8=10u+1100-11u

u=20%

100-u=80%