Question

What is the theoretical yield of aspirin ( C 9 H 8 O 4 ), which has a molar mass of 180.15 g/mol, possible when reacting 3.03 g of salicylic acid with 3.61 mL of acetic anhydride?

Answer 1

Answer:

The theoretical yield of aspirin is 3.95 grams

Explanation:

Step 1: Data given

Mass of salicylic acid = 3.03 grams

Volume of acetic anhydride = 3.61 mL

Density of acetic anhydride = 1.08 g/cm³

Step 2: The balanced equation

C4H6O3+C7H6O3→C9H8O4+C2H4O2

Step 3: Calculate moles salicylic acid

Moles salicylic acid = mass salicylic acid / molar mass salicylic acid

Moles salicylic acid = 3.03 grams /138.121 g/mol

Moles salicylic acid = 0.0219 moles

Step 4: Calculate mass acetic anhydride

Mass acetic anhydride = volume * density

Mass acetic anhydride = 3.61 mL * 1.08 g/mL

Mass acetic anhydride = 3.90 grams

Step 5: Calculate moles acetic anhydride

Moles acetic anhydride = 3.90 grams / 102.09 g/mol

Moles acetic anhydride = 0.0382 moles

Step 6: Calculate limiting reactant

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

Salicylic acid is the limiting reactant. It will completely be consumed. (0.0219 moles). Acetic anhydride is in excess. There will react 0.0219 moles. There remain 0.0382 - 0.0219 =0.0163 moles

Step 7: Calculate moles aspirin

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

For 0.0219 moles salicylic acid we'll have 0.0219 moles aspirin

Step 8: Calculate theoretical yield of aspirin

Mass of aspirin = moles aspirin *molar mass aspirin

Mass of aspirin = 0.0219 moles *180.15 g/mol

Mass of aspirin = 3.95 grams

The theoretical yield of aspirin is 3.95 grams