       Theoretical and Percent Yield Solution to Practice Problem Find the limiting reagent molar mass of p-aminophenol =109.1g/mol molar mass of acetic anhydride = 102.1 g/mol   moles of p-aminophenol = mass/molar mass                                   = 0.157g/(109.1g/mol)                                   = 0.00144 mol   moles of acetic anhydride = mass/molar mass                                          = 0.486g/(102.1g/mol)                                          = 0.00476 mol   From the balanced chemical equation we know that for every mole of p-aminophenol and acetic acid one mole of acetaminophen is produced.   Since there are more moles of acetic anhydride than p-aminophenol, p-aminophenol is used up first as the reaction proceeds.  We can conclude that acetic anhydride is in excess and p-aminophenol is the limiting reagent.   Therefore # moles of p-aminophenol = # of acetaminophen produced Finding the Theoretical Yield   Theoretical Yield = moles of acetamiophen x molar mass of acetaminophen                          = 0.00144 mol x 151.2g/mol                          = 0.217 g     Finding the Percent Yield   Percent Yield =         Actual Yield        x 100%                             Theoretical Yield                       =            0.198g      x 100 %                                   0.217g                     =  91.2 %        Home | Critique  Enter supporting content here 