Question

A 0.4592 g sample of pewter, containing tin, lead, copper, and zinc, was dissolved in acid. Tin was precipitated as SnO 2 ⋅ 4 H 2 O and removed by filtration. The resulting filtrate and washings were diluted to a total volume of 200.0 mL. A 15.00 mL aliquot of this solution was buffered, and titration of the lead, copper, and zinc in solution required 34.07 mL of 0.001476 M EDTA . Thiosulfate was used to mask the copper in a second 20.00 mL aliquot. Titration of the lead and zinc in this aliquot required 33.13 mL of the 0.001476 M EDTA solution. Finally, cyanide was used to mask the copper and the zinc in a third 25.00 mL aliquot. Titration of the lead in this aliquot required 25.11 mL of the 0.001476 M EDTA solution. Determine the percent composition by mass of each metal in the pewter sample.

Cu = ____% Zn= ____% Pb= ____% Sn= ____%

Answer 1