Question

1.) Sodium oxalate, Na2C2O4, in solution is oxidized to CO2(g) by MnO−4 which is reduced to Mn2+. A 50.0 −mL volume of a solution of MnO−4 is required to titrate a 0.342 −g sample of sodium oxalate. This solution of MnO−4 is then used to analyze uranium-containing samples. A 4.60 −g sample of a uranium-containing material requires 32.5 mL of the solution for titration. The oxidation of the uranium can be represented by the change UO2+→UO2+2.

Calculate the percentage of uranium in the sample.

2.) A sample of impure tin of mass 0.536 g is dissolved in strong acid to give a solution of Sn2+. The solution is then titrated with a 0.0448 M solution of NO3−, which is reduced to NO(g). The equivalence point is reached upon the addition of 3.68×10⁻² L of the NO3− solution.

Find the percent by mass of tin in the original sample, assuming that it contains no other reducing agents.