Answer to Question #165253 in General Chemistry for Dylan

Question

A 0.025g sample of aspirin is saponified, treated with excess Fe3+(aq) and diluted to a final volume of 1.00liter. In the spectrometer an absorbance that corresponds to a concentration of 1.35x10-4M is recorded. What % of the sample's mass is due to aspirin?

Answer 1

molarity = no . Of moles / volume

1.35×10^-4 = moles / 1 L

moles = 1.35×10^-4

Mass of Fe³⁺= 1.35×10^-4 × 55.84 = 0.0075 g

Total mass = Mass of aspirin + Mass of Fe³⁺

= 0.025 + 0.0075 = 0.0325

% Mass = $\frac{0.025}{0.0325}$ ×100

% Mass = 76.9 % of the sample's mass is due to aspirin