How to find the relative abundance of isotopes??

Question

10.81=x(10.01294) + x(11.00931)

In this question I have to find the relative abundance of Boron's two isotopes 10 and 11, so how to find the X?

10.81 is the average atomic mass of Boron.

Thank you!!

Answer 1

Hello,

You are close to having the right equation but not quite.

If the total amount of boron is  1

And the fraction which is Boron 10  is X

Then the fraction of Boron 11 is (1 - X)

10.81  = x ( 10.01294)  +  (1-x ) * 11.00931

solving for x

x =  .2000   or 20.00%

remember significant figures.

Hope this helps you.