You begin with 1.5000 g of salicylic acid and prepare aspirin according to the outlined procedure in your lab manual. What is your theoretical yield of aspirin?

Answer 1

salicylic acid + acetic anhydride ==> aspirin + acetic acid

To find theoretical yield of aspirin, we first find moles of salicylic acid used, and assume acetic anhydride in present in excess so that it isn't limiting. We then find theoretical moles of aspirin, and finally convert that to theoretical mass.

moles salicylic acid used = 1.5000 g x 1 mol/138.121 g = 0.0114398 moles

moles aspirin formed = 0.0114398 moles aspirin since it is a 1:1 mole ratio in the balanced equation

mass aspirin = theoretical yield = 0.0114398 moles x 180.158 g/mol = 2.0610 g