Question

Naturally occurring boron is composed of two isotopes. The percent abundance and the mass of each isotope are listed below: 19.99 the boron atoms have a mass of 10.013 amu and 80.1% of the boron atoms have a mass of 11.009 amu. To calculate the average atomic mass of boron, you would set up the following calculation:

Answer 1

The average atomic mass of boron is calculated by multiplying the mass of each isotope by its percent abundance and then summing the two results to find the boron average mass, which is approximately 10.805 amu.

Step-by-step explanation:

To calculate the average atomic mass of boron, which is composed of two isotopes, you would multiply the mass of each isotope by its percent abundance and then add the results together. For boron-10 (¹⁰B) with a mass of 10.0129 atomic mass units (amu) and a percent abundance of 19.9%, you would perform this calculation: (0.199 x 10.0129 amu). Similarly, for boron-11 (¹¹B) with a mass of 11.0093 amu and a percent abundance of 80.1%, the calculation would be: (0.801 x 11.0093 amu). The sum of these two products gives the boron average mass:

Calculation for boron-10: 0.199 x 10.0129 amu = 1.9926 amu

Calculation for boron-11: 0.801 x 11.0093 amu = 8.8124 amu

Atomic mass of boron = 1.9926 amu + 8.8124 amu = 10.805 amu, which is approximately the atomic mass of boron.