How many formula units are contained in 23.5 g of Sb2S3

The molar mass of Sb2S3 is approximately equal to 339.7 g/mol. We calculate the number of moles of Sb2S3 by dividing the given mass by the molar mass.

n = 23.5 g / (339.7 g/mol)

n = 0.0692 mols

To calculate for the number of formula units, we multiply the number of mols by the Avogadro's number,

number of formula units = (0.0692 mols) (6.022 x 10^3)

= 4.167 x 10^22 formula units