Section: Lab 6 CHM 130
Experiment: Identification of Metallic Ions
Metallic ion Flame color
Sodium Na+ Orange
Strontium Sr2+ Pink/Red
Potassium K+ Light blue/Purple
Barium Ba2+ Yellow
Copper Cu2+ Green
Lithium Li+ Pink
Calcium Ca2+ Pink/Orange
Unknown Pink/Red - Strontium
A - All chemical used in this test are binary compounds. What portion of the periodic table is responsible for the color observed? The metals portion.
B - In cooking over an open flame, a yellow flame is often observed when some food is spilled into the flame? What is most likely responsible for the yellow flame color? Barium is most likely responsible. It burned yellow over the flame.
C - What problems might be associated with using flame color for identification purposes? Some of the colors can look similar. Also, if you don’t have enough of the substance on the Q-tip, the flame will start to burn that instead and will turn a different color.
D - Explain how the observed colors are produced. As the substances are heated, the electrons move to higher energy levels by absorbing the heat. This state is unstable and the electrons tend to return to their ground state and release the absorbed heat energy in the form of electromagnetic energy. A portion of this energy being released is in the visible light region.
E – Disposing of chemicals is an important aspect of any chemistry laboratory experiment. Explain in detail how you disposed of any remaining chemicals when you completed this experiment. Your instructor may request pictures documenting your disposal techniques and procedures. I rinsed all chemicals remaining in the well plate down the sink with lots of water and set it out to dry before returning it to the box.