Question

15.8 grams of NH3 and excess O2 produces NO gas and H2O. 12.8 grams of NO gas was produced. Find the percent yield.
Balanced Equation: 4 NH3 + 5 O2 -> 4 NO + 6 H2O

Answer 1

Here is an example of a simple stoichiometry problem. Percent yield is given at the bottom of the example. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html