I PREPARED ASPIRIN USING 2.019 g of salicylic acid and 5.2 ml of acetic anhydride (D = 1.08 G/ML)?

Question

1)WHICH REACTANT IS LIMITING..SALICYLIC ACID OR ACETIC ANHYDRIDE?

2)WHAT IS THE THEORETICAL YIELD OF ASPIRIN?

3)IF I OBTAINED 1.789G OF ASPIRIN, WHAT IS THE PERCENT YIELD? REALLY CONFUSED

Answer 1

First try to know how many moles of reactants to reat with each other:
(salicylic acid) + (acetic anhydride) --> (Aspirin) + (acetic-acid)\This means every mole of salicylic acid would react with one mole of acetic anhydride.
Second convert every thing into moles:
Molar mass of salicylic acid: 138.123 g/mol
2.019 g of salicylic acid = 0.01462 mole of salicylic acid
Molar mass of acetic anhydride: 102.1 g/mol
5.2 ml of acetic anhydride = 5.6g of acetic anhydride = 0.055 mole of acetic anhydride.
Since 0.01462 < 0.055, salicylic acid is the limiting reactant.
Mol. mass of Aspirin: 180.160 g/mol
THE THEORETICAL YIELD OF ASPIRIN = 0.01462 mol*180.160 g/mol = 2.634g
THE PERCENT YIELD = 1.789g/2.634g = 67.92%.