An element has two isotopes. One has an abundance of 73.25% and an atomic mass of 63.45amu and the second has an abundance of 26.75% an an atomic mass of 68.15 amu. What is the average atomic mass of the element?

Question

anonymous · Answer

$\color{green} {\text{avg = [fraction of A][mass of A] + [fraction of B][mass of B] + $\ldots$}} $

harleyquinn · Answer

I'm confused...

anonymous · Answer

Take the percentage and divide by 100 to get the mole fraction. Then multiply each mole fraction by the atomic mass of the isotopes. Add the result, and you have the average. It is a weighted average.