Question

A student prepared asprin in a lab experiment using the reaction that asprin(C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The Student reacted 1.50 g salicylic acid with 2.00 g acetic anhydride. The yield was 1.50 g aspring. Calculate the theoretical yield and the percent yield for this experiment.

Answer 1

The theoretical yield is 1.96 grams of aspirin. The % yield is 76.5%

Step-by-step explanation:

Step 1: Data given

Mass of salicylic acid (C7H6O3) = 1.50 grams

Mass of acetic anhydride (C4H6O3) = 2.00 grams

Yield of aspirin = 1.50 grams

Molar mass of salicylic acid = 138.12 g/mol

Molar mass of acetic anhydride = 102.09 g/mol

Step 2: The balanced equation

C4H6O3 + C7H6O3 → C9H8O4 + C2H4O2

Step 3: Calculate moles of C7H6O3

Moles C7H6O3 = Mass C7H6O3 / molar mass C7H6O3

Moles C7H6O3 = 1.50 grams / 138.12 g/mol

Moles C7H6O3 = 0.0109 moles

Step 4: Calculate moles of C4H6O3

Moles C4H6O3 = 2.00 grams / 102.09 g/mol

Moles C4H6O3 = 0.0196 moles

Step 5: Calculate the limiting reactant

salicylic acid has the smallest amount of moles, so it's the limiting reactant.

It will completely be consumed.

Acetic anhydride is in excess. There will be consumed 0.0109 moles

There will remain 0.0196 - 0.0109 = 0.0087 moles

Step 6: Calculate moles of aspirin

For 1 mol of salicylic acid, we need 1 mol of acetic anhydride to produce 1 mol aspirin

For 0.0109 moles of salicylic acid we have 0.0109 moles of aspirin

Step 7: Calculate mass of aspirin

Mass aspirin = 0.0109 moles * 180.158 g/mol

Mass aspirin = 1.96 grams (= theoretical yield)

Step 8: Calculate % yield

% yield = actual yield / theoretical yield

% yield = (1.50 grams / 1.96 grams ) * 100%

% yield = 76.5 %

The theoretical yield is 1.96 grams of aspirin. The % yield is 76.5%