Answer
1.33 mol
Work Step by Step
Calculating how much product can be made based on the amount of each reactant, we have
$4\,mol\,Mn\times\frac{1\,mol\,Mn_{3}O_{4}}{3\,mol\,Mn}=\frac{4}{3}\,mol\,Mn_{3}O_{4}=1.33\,mol$
$7\,mol\,O_{2}\times\frac{1\,mol\,Mn_{3}O_{4}}{2\,mol\,O_{2}}=\frac{7}{2}\,mol\,Mn_{3}O_{4}=3.5\,mol$
Since $Mn$ makes the least amount of product, it is the limiting reactant.
Theoretical yield is the maximum amount of product that can be made in a reaction based on the amount of limiting reactant.
Therefore, theoretical yield= $1.33\,mol$.