In the Classroom edited by
JCE DigiDemos: Extensions
Ed Vitz
Kutztown University Kutztown, PA 19530
Demonstration Extensions: Flame Tests and Electrolysis Inexpensive Alcohol Burners for Flame Tests Using Aluminum Tea Light Candle Holders Tom Mortier, Annie Wellens, Marie-Josée Janssens* Department of Health and Technology, Leuven Catholic University College, Herestraat 49, B-3000 Leuven, Belgium; Department of Chemistry, Catholic University of Leuven, Celestijnenlaan 200 G, B-3001 Leuven-Heverlee, Belgium; *
[email protected] Flame tests are beautiful and spectacular classroom demonstrations illustrating the differences in the atomic spectra of various elements as an introduction to Bohr’s atomic theory (1). A number of demonstrations on the classic flame test technique have been reported in this Journal (1–8). We describe alcohol burners made from different metal salt/methanol solutions in recovered aluminum tea light candle holders giving beautiful colored flames for several minutes. The exact concentration of the metal salts is not important. The empty aluminum tea light candle holders are filled with the metal salt/methanol solutions and placed in Petri dishes half filled with water. This cools the aluminum holders during the burning experiments and gives attention to safety prescriptions in a classroom experiment. When the same demonstrations are performed directly in Petri dishes, the heating often causes the glass to break. The flames are approximately 7 cm high and therefore this demonstration can be used easily for a classroom
522
up to 25 students. The methanol burners last several minutes. However, the flame can be extinguished earlier by placing a beaker upside down on the tea light candle holders in the water. This has the additional advantage of demonstrating that oxygen from the air is needed during the flame test demonstrations and hence, it illustrates that the flame extinguishes when all the oxygen is consumed. Literature Cited
1. 2. 3. 4. 5. 6. 7. 8.
Smith, E. T. J. Chem. Educ. 1995, 72, 828. Sanger, M. J. J. Chem. Educ. 2004, 81, 1776A. Johnson, K. A.; Schreiner, R. J. Chem. Educ. 2001, 78, 929. Dragojlovic, V. J. Chem. Educ. 1999, 76, 929. McKelvy, G. M. J. Chem. Educ. 1998, 75, 55. Dalby, D. K.; Mosher, M. M. J. Chem. Educ. 1996, 73, 80. McRae, R. A.; Jones, R. F. J. Chem. Educ. 1994, 71, 68. Ragsdale, R. O.; Driscoll, J. A. J. Chem. Educ. 1992, 69, 828.
Supporting JCE Online Material
http://www.jce.divched.org/Journal/Issues/2008/Apr/abs522_2.html Full text (HTML and PDF) with links to cited JCE articles Supplement Find “Inexpensive Alcohol Burners for Flame Tests Using Aluminum Tea Light Candle Holders” in the JCE Digital Library at http://www.jce.divched.org/JCEDLib/DigiDemos/index.html.
Journal of Chemical Education • Vol. 85 No. 4 April 2008 • www.JCE.DivCHED.org • © Division of Chemical Education
