Question

challenge problems
taken ap chem 2022 free-response questions answer: 0.2772 g hc₇h₅o₃

1. a student reacts 0.300 g of methyl salicylate (c₈h₈o₃) with a stoichiometric amount of a strong base. this product is then acidified to produce salicylic acid crystals (hc₇h₅o₃).

(a) for every 1 mole of c₈h₈o₃ (molar mass 152.15 g/mol) reactant used, 1 mole of salicylic acid crystals (hc₇h₅o₃, molar mass 138.12 g/mol) is produced. calculate the maximum mass, in grams, of hc₇h₅o₃ that could be produced in this reaction.

Explanation:

Step1: Calculate moles of \( C_8H_8O_3 \)

Moles = \( \frac{\text{Mass}}{\text{Molar Mass}} \), so \( \frac{0.300\ \text{g}}{152.15\ \text{g/mol}} \approx 0.001972\ \text{mol} \)

Step2: Determine moles of \( HC_7H_5O_3 \)

Mole ratio \( C_8H_8O_3 : HC_7H_5O_3 = 1:1 \), so moles of \( HC_7H_5O_3 = 0.001972\ \text{mol} \)

Step3: Calculate mass of \( HC_7H_5O_3 \)

Mass = Moles × Molar Mass = \( 0.001972\ \text{mol} × 138.12\ \text{g/mol} \approx 0.2722\ \text{g} \)

Answer:

\( 0.2722\ \text{g} \)