Thank you for sharing


Monique Wilhelm
Dept of Chemistry & Biochemistry
University of Michigan-Flint

From: "Debbie M. Decker"
Date:06/20/2014 12:04 PM (GMT-05:00)
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: [DCHAS-L] Rainbow Demonstration - New and Improved!

Hi and Hello:

To my distress, I discovered this demonstration is used frequently in my Department.  I asked one of my staff to determine a better, safer way to accomplish the demo.  She took on this project with gusto and wrote me a very nice report (which will be submitted to JCHAS).

But here’s the basic information:


New Instruction 4 – Wooden Applicators Soaked in Saturated Salts Solutions

Saturated salt solutions were prepared according to the table below. See Demo Prep Notebook#1 pg 5 for exact preparation. Note g were added to 250ml DI water (not brought to volume).


Actual

Salt

g in 250 mL H2O

BaCl2/BaCl2 • 2H2O

106

CaCl2

190

CuCl2 • H2O

288

LiCl

233

KCl

88

NaCl

91

SrCl2

392


Salts solutions were prepared in DI water. Five Wooden applicators were broken in half and placed in a weight boat. The saturated solutions were poured into the weigh boats to cover the applicators. Solutions were allowed to evaporate. Most salt solutions evaporated in 1 week. CaCl2 and LiCl were still damp after 4 months.



Salts Results:

Barium Chloride BaCl2*2H2O  (light green) - color flame clearly distinguishable

Calcium Chloride CaCl2 (orange red) – color flame clearly distinguishable

Copper Chloride CuCl2 (blue/green) – color flame clearly distinguishable

Lithium Chloride LiCl (fushia flame) – color flame clearly distinguishable

Potassium Chloride KCl (light lilac) – color flame distinguishable (better than any other tested)

Sodium Chloride NaCl (yellow flame) – color flame clearly distinguishable

Strontium Chloride SrCl2 (red or crimson flame) – color flame clearly distinguishable


Flame Tests were performed on damp CaCl2 and LiCl. All other salts were dry. Wooden applicators need an additional flame source to burn.  Just burning applicators alone did not produce a flame able to be seen from more than a feet away.  A Bunsen burner or handheld propane torch were used with similar results.  Results were spectacular, even potassium chloride was able to be seen.
If you have any questions, feel free to contact me.


Debbie M. Decker, CCHO
Safety Manager
Department of Chemistry
University of California, Davis
122 Chemistry
1 Shields Ave.
Davis, CA  95616
(530)754-7964
(530)304-6728

dmdecker**At_Symbol_Here**ucdavis.edu<mailto:dmdecker**At_Symbol_Here**ucdavis.edu>

Birkett's hypothesis: "Any chemical reaction
that proceeds smoothly under normal conditions,
can proceed violently in the presence of an idiot."