The table below gives the data that is needed to calculate the average atomic mass of element B.IsotopeAtomic mass (amu)Relative abundance (%)B-1010.0119.91B-1111.0180.09Based on these data, what is the average atomic mass of element B?

Convert the abundances to decimals and calculate the weighted average: (10.01 × 0.1991) + (11.01 × 0.8009) = 10.8109 amu. Rounded to the nearest hundredth, the average atomic mass is 10.81 amu, choice C.

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