Colored H2 Balloon Explosions
(Reference: Fortman, J.J. J. Chem. Ed. 1991, 68, 168.)
 

Flame Tests : Atomic Theory : Spectroscopy : Explosions
 

Purpose:
Illustrate different colors associated with different metals, due to the loss of energy by an excited electron of that certain element.
 

Safety:
Wear chemical splash goggles when inflating and igniting the balloons.  Reduce amount of solid in smaller rooms.  Make sure to ignite balloon at lowest level to ensure all of the metal reacts.  Do not use toxic salts such as barium, lithium, nor aluminum (Al(OH)3is a lung irritant).  Best to do outside if weather permitting.
 

Materials:
Hydrogen gas cylinder, or source
14 inch round balloons
String
Solids (eg. strontium nitrate (red), cupric chloride (blue), potassium chloride, rubidium chloride, powdered iron (yellow))
Taped match to a meter stick
 

Procedure:
Place about a teaspoon of the solid into the balloon and then inflate with hydrogen gas.  Tie the balloon with a string and then anchor it.  The solid will settle and balloon will float.  Ignite the balloons!

 
Explanation:
The electrons in the salt molecules are excited to a higher level by the heat energy from the balloon, and when they release that energy it is in the form of light.  In the case of each salt, depending on itís characteristic absorption and emission of energy, the colors will differ.
 

Clean-up:
Discard any balloon pieces in the trash
 
 

Ginger Chateauneuf, 2000.
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