“The Project”
An Unknown Ionic Compound in the Landfill

Introduction
Upon discovery of an unknown solid ionic compound in a landfill by the Chemistry 1146 laboratory group, precautions were immediately taken and rigorous experimentations were begun to determine the identity of the compound. Determining the identity of this compound was very crucial for the safety of the community. The chemical and physical properties of the compound could then be identified and environmental hazards addressed. Questions that needed to be answered in relation to this unknown compound included: Is it a risk to people living nearby? What if it gets in the water supply? Does it contaminate the air? Is it reactive? Over a three week time-span the chemists experimented with the unknown compound to report the findings back to the community. After the unknown compound was identified, the chemists studied its properties and confirmed the identity by synthesizing the compound in the lab and comparing it to the unknown.
Experimental
Week 1
After a sample of the unknown compound (#21) was retrieved, various experiments were carried out to determine the chemical formula. An anion analysis was first performed on the unknown compound. A solution of the unknown compound was prepared by taking a small amount of the solid on the end of a scoopula and dissolving it in 2 mL of distilled water (DI water) in a test tube. The compound was then tested for the sulfate ion by placing 1 mL of the solution in a test tube and adding 1 mL 6 M HCl and 1 mL of BaCl₂ solution. A white precipitate proves the presence of a sulfate ion. (aq) + (aq) (s) + 2 (aq)
A carbonate ion analysis was also performed by adding 1 mL of the unknown solution in a test tube and adding 6 M HCl one drop at a time. If bubbles form after each drop is added, a carbonate ion is present.

When anion analysis was completed,