Calculate the percent yield for an experiment in which 46.9 g of SO3 was produced upon the reaction of 51.2 g of SO2 with 25.0 g O2

Answer 1

2SO2 + O2 ==> 2SO3

mols SO2 = grams/molar mass
mols O2 = grams/molar mass = ?

Using the coefficients in the balanced equation, convert mols SO2 to mols SO3
Do the same for mols O2 to mols SO3.
It is likely these values will be different which means one of them is wrong. The correct answer in limiting reagent problems is ALWAYS the smaller value and the reagent producing that value is the limiting reagent.

Now convert the smaller value to g SO3. g = mols x molar mass. This is the theoretical yield (TY). The actual yield (AY) from the problem is 46.9.
Then %yield = (AY/TY)*100 = ?