%yield = 54.6%
Percent yield is the compare of the amount of product obtained from a reaction with the amount you calculated
(theoretical)
General formula:
Percent yield = (Actual yield / theoretical yield )x 100%
Reaction
2ZnS+3O₂ ⇒ 2ZnO+2SO₂
MW ZnS = 97.474 g/mol
[tex]\tt \dfrac{150}{97.474}=1.54[/tex]
MW ZnO = 81.38 g/mol
[tex]\tt \dfrac{2}{2}\times 1.54=1.54[/tex]
[tex]\tt 1.54\times 81.38=125.33~g[/tex]
Theoretical production = 125.388
[tex]\tt \dfrac{68.5}{125.33}\times 100\%=\boxed{\bold{54.6\%}}[/tex]