Aspirin, C9H8O4, is synthesized by the reaction of salicylic acid, C7H6O3, with acetic anhydride, C4H6O3

Question

2C7H6O3 + C4H6O3 → 2C9H8O4 + H2O



When 20.0 g of C7H6O3, and 20.0 g of C4H6O3 react, what is the limiting reactant?

If 22.03 g of C9H8O4, are produced in the lab what is the percent yield?

Answer 1

The 20.0g C₇H₆O₃ * (1 mol C₇H₆O₃ /138.0g C₇H₆O₃ ) * (2 mol C₉H₈O₄ /2 mol C₇H₆O₃ ) = 0.1449 mol C₉H₈O₄ .

The 20.0g C₄H₆O₃ * (1 mol C₄H₆O₃ /102.0g C₄H₆O₃ ) * (2 mol C₉H₈O₄ /1 mol C₄H₆O₃ ) = 0.3920 mol C₉H₈O₄ . So C₇H₆O₃ is the winner because some of the other chemical remains when this is consumed.

The theoretical yield is (0.1449 mol C₉H₈O₄ ) * (180.1g C₉H₈O₄ /1 mol C₉H₈O₄ ) = 26.09g C₉H₈O₄ .

The percent yield is 100 * actual / theoretical = 100 * (22.03/26.09) = 84.44%.