How would I solve this

Question

The student reacted 3.00 g salicylic acid (C₇H₆O₃) with 4.00 g acetic anhydride (C₄H₆O₃). The yield was 3.00 g aspirin. Calculate the theoretical yield and the percent yield for this experiment.

C₇H₆O₃ + C₄H₆O₃  C₉H₈O₄ + HC₂H₃O₂

Answer 1

Salicylic acid + acetic anhydride ==> acetyl salicylic acid (aspirin) + acetic acid.

C₇H₆O₃ + C₄H₆O₃ ==> C₉H₈O₄ + C₂H₄O₂

moles salicylic acid present = 3.00 g x 1 mole/138 g = 0.02174 moles

moles acetic anhydride present = 4.00 g x 1 mol/102 g = 0.0392 moles

LIMITING REACTANT is salicylic acid (1:1 mole ratio and there is less salicylic acid)

Theoretical yield of aspirin:

0.02174 moles salicylic acid x 1 mole aspirin/mol salicylic acid x 180 g aspirin/mol = 3.91 g aspirin

Percent yield of aspirin:

3.00 g/3.91 g (x100%) = 76.7 % yield