Question

Using the information in the table to the right, calculate the average atomic mass of strontium. Report to two decimal places.

ANSWER: 87.62 amu

Answer 1

87.62 amu.

Step-by-step explanation:

1. The average atomic mass of an element can be calculated as the summation of the atomic mass units of each isotope multiplied by its (abundance % / 100).

• ∴ The average atomic mass of strontium (Sr) = [(atomic mass of Sr-84)(Abundance / 100) + (atomic mass of Sr-86)(Abundance / 100) + (atomic mass of Sr-87)(Abundance / 100) + (atomic mass of Sr-88)(Abundance / 100)].

• The average atomic mass of strontium (Sr) = [(83.913428)(0.0056) + (85.909273)(0.0986) + (86.908902)(0.07) + (87.905625)(0.8258)] = 87.6166 amu ≅ 87.62 amu.

Answer 2

87.62 amu.

Step-by-step explanation:

• The average atomic mass of an element can be calculated as the summation of the atomic mass units of each isotope multiplied by its (abundance % / 100).

∴ The average atomic mass of strontium (Sr) = [(atomic mass of Sr-84)(Abundance / 100) + (atomic mass of Sr-86)(Abundance / 100) + (atomic mass of Sr-87)(Abundance / 100) + (atomic mass of Sr-88)(Abundance / 100)].

• The average atomic mass of strontium (Sr) = [(83.913428)(0.0056) + (85.909273)(0.0986) + (86.908902)(0.07) + (87.905625)(0.8258)] = 87.6166 amu ≅ 87.62 amu.