Cooper is made up of two isotopes, Cu-63 (62.9296 amu) and Cu-65 (64.9278 amu). Given Cooper's atomic weight of 63.546. what is the percent abundance of each isotope?

Answer 1

Let's assume that the percent abundance of Cu-63 is x, and the percent abundance of Cu-65 is (1-x) since the total percent abundance is 100%.

The atomic weight can be calculated using the formula:

Atomic weight = (mass of isotope 1 * percent abundance of isotope 1) + (mass of isotope 2 * percent abundance of isotope 2)

63.546 = (62.9296 * x) + (64.9278 * (1-x))

Now, let's solve for x:

63.546 = 62.9296x + 64.9278 - 64.9278x

63.546 - 64.9278 = -1.9982x

-1.3818 = -1.9982x

x = -1.3818 / -1.9982

x ≈ 0.691 or 69.1% (rounded to one decimal place)

Therefore, the percent abundance of Cu-63 is approximately 69.1% and the percent abundance of Cu-65 is approximately 30.9%.