Gravimetric Analysis Sample Problem

Gravimetric Analysis Practice Problems

1. Outline the steps that are required to solve a typical gravimetric analysis problem.

2. A 2.00g sample of limestone was dissolved in hydrochloric acid and all the calcium present in 2+ the sample was converted to Ca (aq).

Excess ammonium oxalate solution, (NH4)2C2O4(aq), was added to the solution to precipitate the

calcium ions as calcium oxalate, CaC2O4(s).

The precipitate was filtered, dried and weighed to a constant mass of 2.43g.

Determine the percentage by mass of calcium in the limestone sample.

3. A 3.00- g sample of an alloy (containing only Pb and Sn) was dissolved in nitric acid (HNO3).

Sulfuric acid was added to this solution, which precipitated 1.69 g of PbSO4. Assuming that all of the lead was precipitated, what is the percentage of Sn in the sample?

4. An empty crucible has a mass of 12.770 grams. The crucible and hydrate have a mass of 13.454 grams. After heating, the crucible and anhydrous salt have a mass of 13.010 grams. . What is the formula of this hydrate of MgSO4 ?H2O?