Question

An element has an atomic mass of 69.66 amu. It has two

isotopes, The first isotope has an atomic mass of 68.9255
amu. The second one has an atomic mass of70.9247
amu. What is the abundance of the first isotope?

Answer 1

Answer: 63.26%

Step-by-step explanation:

If we let the abundance of the first isotope be x, then:

`69.66=(68.9255)(x)+(70.9247)(1-x)\\69.66=68.9255x+70.9247-70.9247x\\-1.2647=-1.9992x\\x=(-1.2647)/(-1.9992) \approx 0.6326`

Which is equal to 63.26%