SOLVED: Explain how to determine the average atomic mass from knowing the percent abundance of isotopes

Transcript

Here we have a question about determining the average atomic mass knowing the percentage of abundance of isotopes of these same elements. So the average atomic mass will be equal to the fraction of isotope 1 times the mass of isotope 1 plus the fraction of isotope 2 times. The mass of isotope 2- and this will continue on for, however many isotopes. There are, for example, considering carbon say that 75 percent of carbon is in the isotope carbon 12 and 25 percent of it is in the form of carbon 13 point. It has 1 more neutrons in its nucleus. We will multiply the fraction of carbon 12 times the massive carbon 12 point so 0.75 times 12 plus the fraction of carbon 13.0 .25 times 13, giving us an average atomic mass of 12.25. A m! U.