Aspirin can be made in the laboratory by reacting acetic anhydride (C₄H₆O₃) with salicylic acid (C₇H₆O₃) to form aspirin (C₉H₈O₄) and acetic acid (C₂H₄O₂). The balanced equation is: C₄H₆O₃ + C₇H₆O₃ → C₉H₈O₄ + C₂H₄O₂ In a laboratory synthesis, a student begins with 3.00 mL of acetic anhydride (density = 1.08 g/mL) and 1.25 g of salicylic acid. Once the reaction is complete, the student collects 1.22 g of aspirin. Determine the limiting reactant. Determine the theoretical yield of aspirin. Determine the percent yield for the reaction.

Verified step by step guidance

1. Calculate the mass of acetic anhydride using its volume and density: \( \text{mass} = \text{volume} \times \text{density} \).
2. Convert the mass of acetic anhydride to moles using its molar mass: \( \text{moles} = \frac{\text{mass}}{\text{molar mass}} \).
3. Convert the mass of salicylic acid to moles using its molar mass: \( \text{moles} = \frac{\text{mass}}{\text{molar mass}} \).
4. Determine the limiting reactant by comparing the mole ratio of the reactants to the stoichiometry of the balanced equation.
5. Calculate the theoretical yield of aspirin based on the limiting reactant and then determine the percent yield using the formula: \( \text{percent yield} = \left( \frac{\text{actual yield}}{\text{theoretical yield}} \right) \times 100 \).

Key Concepts

Limiting Reactant

The limiting reactant is the substance that is completely consumed first in a chemical reaction, thus determining the maximum amount of product that can be formed. To identify the limiting reactant, one must compare the mole ratios of the reactants based on the balanced chemical equation. The reactant that produces the least amount of product is the limiting reactant.

Theoretical Yield

The theoretical yield is the maximum amount of product that can be generated from a given amount of reactants, as calculated from the balanced chemical equation. It is determined by using the limiting reactant to find out how much product can be formed under ideal conditions, assuming complete conversion and no losses during the reaction.

Percent Yield

Percent yield is a measure of the efficiency of a chemical reaction, calculated by comparing the actual yield of a product obtained from the reaction to the theoretical yield. It is expressed as a percentage and is calculated using the formula: (actual yield / theoretical yield) × 100. This value helps assess how well the reaction proceeded and can indicate potential losses or inefficiencies.