University:
University of Arkansas
Course:
CHEM 1053 | Chemistry in the Modern World
Academic year:

2023
Views:

307

Pages:

2
Author:

madeleinejames20

In this example, we will calculate the natural abundance of an isotope. Our problem states that copper contains two naturally occurring isotopes – copper 63 with a mass of 60.2.9 296 amu and copper 65 with a mass of 60.4.92 7 8 amu. Using the periodic table, we need to calculate the natural abundance of copper 65. The first thing we can do is write out the equation for the atomic mass of copper and determine how the information we're given in the problem fits into this equation. From the periodic table, we know that the atomic mass of copper is 63.5 46 amu. We are given the masses of 63 and 65, but we're not given the natural abundances of 63 or 65. However, we do know that because there are only two naturally occurring isotopes, if we add up their natural abundances, we should get one. So we can solve for the natural abundance of 63 in terms of the natural abundance of 65. The natural abundance of 63 is 1 minus the natural abundance of 65. We can plug these values into the equation above, and we have one unknown, which is the abundance of copper 65. So we can solve for the abundance of copper 65 by first distributing 1 minus the abundance of copper 65 to 60.2.9 296. Then we can group like terms on each side, so we'll have 62.5.46 minus 60.2.9 296, which gives us 0.6164 on the left. On the right, we'll take 64.9.27 8 times the abundance of 65, subtract 62.9.2 9 6 times the abundance of 65, to get 1.9982 times the abundance of 65. Solving for the abundance of 65, we will have 0.6164 divided by 1.9982, which is 0.308. So, this is the natural abundance of copper 65.