Chem 2/5 Post-Laboratory Assignment
Fall 1996

Experiment #423-Determining the Empirical Formula of a Compound

1.) Determine the empirical formula of the substance formed when aluminum metal is heated in air. Assume that the only reaction occurring is between the oxygen (O2) in the air and the aluminum.

Mass of crucible and cover: 28.887g
Mass of crucible, cover, and aluminum: 31.360g
Mass of crucible, cover, and aluminum oxide: 33.559g

2.) Write a chemical equation(s) for the reaction of lithium with air if the weather conditions of a typical day in Rolla are cloudy skies, temperature of 70oF with a relative humidity of 90%. Consider all potentially reactive components of air.

3.) When weighing the crucibles, why should you refrain from touching them with your fingers?