How many total atoms are in 0.920 g of P2O5?

Given:

0.920 g of P2O5

Required:

Total atoms

Solution:

The molar mass of P2O5 is 284 grams per mole.

0.920 grams / 284 grams per mole of P2O5 = 3.24 x 10^-3 mole P2O5

Using Avogadro’s law where 1 mole of substance equals 6.023 x 10^23 atoms

3.24 x 10^-3 mole P2O5 (6.023 x 10^23 atoms/mole) = 1.95 x 10^21 atoms P2O5