Question

Calculate the atomic weight (in amu) of an element (X) given the following data:

24X: 24.000 amu at 0.7870 fractional abundance

26X: 26.000 amu at 0.1017 fractional abundance

25X: 25.000 amu at 0.1113 fractional abundance

Answer 1

multiply each isotopes mass by it's percent/fractional abundance (to get the weighted average) and add them all up, like this:

(mass of isotope #1) x (% abundance) + (mass isotope #2) x (% abundance) +... = atomic weight

Answer 2

thanks