Question

The atomic weight of a newly discovered element is 110.352 amu. It has two naturally
occuring isotopes. One has a mass of 111.624
amu. The other has an isotopic mass of
109.875 amu. What is the percent abundance
of the last isotope (109.875 amu)?

Answer 1

Is that all the information you have?

Answer 2

The last isotope will have a higher % abundance because is closer to 110

Answer 3

It's a multiple choice question if that helps: 1. 62.5%
2. 45.8%
3. 27.3%
4. 72.7%
5. 37.5%
6. 54.2%

Answer 4

that does help

Answer 5

it's 72.7

Answer 6

Trial and error
111.624 f + 109.875 (1 - f) = 110.352.
Solving, f = 0.2727, so 1 - f = 0.7273, or 72.73% of the 109.875 amu isotope.