Determine the mass in grams of 8.42 × 10²¹ atoms of barium. (The mass of one mole of barium is 137.33 g.)

Answer 1

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Number of moles = Number of atoms / Avogadro's number

Number of moles = 8.42 × 10^21 atoms / (6.022 × 10^23 atoms/mol)

Number of moles ≈ 0.014 moles

Now, you have the number of moles, and you can calculate the mass using the molar mass

Mass (grams) = Number of moles × Molar mass Mass (grams) =

0.014 moles × 137.33 g/mol Mass (grams) ≈ 1.92 grams