Question

What is the theoretical yield of aspirin (180.2 g/mol) in the reaction of 2.94 grams of salicylic acid (138.1 g/mol) with excess acetic anhydride (102.1 g/mol)? Show your work. Include UNITS and round your final answer appropriately.

Answer 1

Theoretical Yield of Aspirin = 3.84 g

Step-by-step explanation:

The reaction between salicylic acid (C7H6O3) and acetic anhydride (C4H6O3) to form aspirin(C9H8O4) and acetic acid (HC2H3O2) is:

`C7H6O3 + C4H6O3 \rightarrow  C9H8O4 + HC2H3O2`

Mass of salicylic acid present = 2.94 g

Molar Mass of salicylic acid = 138.1 g/mol

`Mole\ salicylic\ acid = (2.94)/(138.1g/mol) =0.0213\ moles`

Since acetic anhydride is in excess, salicylic acid will be the limiting reagent and will determine the amount of product formed.

Based on the reaction stoichiometry:

1 mole of salicylic acid yields 1 mole of aspirin

Therefore, Moles of aspirin = 0.0213

Molar mass of aspirin = 180.2 g/mol

`Mass (aspirin) = moles*mol mass = 0.0213 * 180.2 =3.84 g`