Question

What is the percentage occurrence of the isotopes `""^35Cl`, and `""^37Cl` is the average atomic mass of chlorine is `35.45*"amu"`?

Answer 1

The weighted average of the isotopes is `35.45*"amu....."`

Explanation:

And thus `x_1xx35*"amu"+x_2xx37*"amu"=35.45*"amu"`.

This is one equation in 2 unknowns. However, we can supply another equation because WE ASSUME that there are only the two isotopes of `Cl`, `""^35Cl` and `""^37Cl`, and thus `x_2=1-x_1`.

And thus we get the equation:

`x_1xx35+(1-x_1)xx37=35.45`

So `37-2x_1=35.45`

And `x_1=(37-35.45)/2=0.775`

And `x_2=0.225`.

And thus `%` `""^35Cl=77.5%`, and `%` `""^37Cl=22.5%`.

Capisce?