Question

express your answer to four significant figures and include the appropriate units. calculate the atomic mass for boron using the weighted - average mass method. there are two naturally occurring isotopes: b - 10, which has a percent abundance of 19.88% and a mass of 10.013 amu, and b - 11, which has a 80.12% abundance and a mass of 11.009 amu. refer to reference (page) section 4.5 while completing this problem.

Explanation:

Step1: Convert abundances to decimals

B-10: \(19.88\% = 0.1988\), B-11: \(80.12\% = 0.8012\)

Step2: Calculate contributions

B-10: \(10.013 \, \text{amu} \times 0.1988 = 1.9906 \, \text{amu}\)
B-11: \(11.009 \, \text{amu} \times 0.8012 = 8.8204 \, \text{amu}\)

Step3: Sum contributions

\(1.9906 + 8.8204 = 10.8110 \, \text{amu}\)

Step4: Round to 4 significant figures

\(10.81 \, \text{amu}\)

Answer:

10.81 amu