Heating an ore of antimony (Sb2S3) in the presence of iron gives the element antimony and iron(II) sulfide.

Question

Sb2S3(s) + 3Fe(s) ---> 2Sb(s) + 3FeS(s)
When 15.0 g Sb2Sb3 reacts with an excess of Fe, 9.84 g Sb is produced. What is the percent yield of this reaction?

Answer 1

Here is a worked example of a stoichiometry problem. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html