Question

Which of the following describes how the weighted average atomic mass of an element with two isotopes is determined?

a) (mass of isotope A + mass of isotope B) / 2
b) (mass of isotope A + mass of isotope B) * (% abundance of isotope A + % abundance of isotope B)
c) (mass of isotope A * % abundance of isotope A) + (mass of isotope B * % abundance of isotope B)
d) 2(mass of isotope A + mass of isotope B) / (% abundance of isotope A + % abundance of isotope B)

Answer 1

The weighted average atomic mass of an element with two isotopes is determined by multiplying the mass of each isotope by its percentage abundance and then summing the products.

Step-by-step explanation:

The weighted average atomic mass of an element with two isotopes is determined by multiplying the mass of each isotope by its percentage abundance and then summing the products. The formula for calculating the weighted average atomic mass is: (mass of isotope A * % abundance of isotope A) + (mass of isotope B * % abundance of isotope B).

For example, if we have two isotopes, A and B, with masses of 12 amu and 14 amu, and percentage abundances of 70% and 30%, respectively, the weighted average atomic mass would be calculated as: (12 amu * 0.7) + (14 amu * 0.3) = 12.6 amu + 4.2 amu = 16.8 amu.