A sample of an iron sulfide contains 2.561g of metal, and 2.206g of sulfur. What is the empirical formula of iron sulfide?

1 Answer
Jun 10, 2016

Fe2S3

Explanation:

Moles of iron = 2.561g55.85gmol1 = 0.0459mol

Moles of sulfur = 2.206g32.06gmol1 = 0.0688mol

If we divide thru by the lower molar quantity, we get, FeS1.5. However, by definition, the empirical formula is the simplest WHOLE number that defines constituent elements in a species, so we double the formula to get WHOLE numbers:

Fe2S3.