Genie in a Bottle

DESCRIPTION:
This demo makes use of the catalytic decomposition of hydrogen peroxide to produce a column of steam out of a flask, that looks like a genie coming out of a bottle.
2H2O2 → 2H2O + O2, KI is a catalyst

TOPICS COVERED:
- decomposition reactions
- catalysis
- exothermic reactions
- evolution of a gas
- color change
- chemical change

MATERIALS NEEDED:
- 1000mL volumetric flask w/ stopper
- aluminum foil
- kimwipe
- a piece of string
- KI
- 30% H2O2
- scissors

PROCEDURE:
1. Put 2g of KI on a kimwipe, wrap the kimwipe into a sachet, and tie shut, any extra wipe can be cut off the top
2. Put 40mL of H2O2 into the flask
3. Suspend the sachet into the flask with the string, do not let the sachet touch the H2O2
4. Stopper the flask so that the stopper holds the string dangling the sachet in place
5. Wrap the flask in foil so that students can’t see what is inside, now the flask is ready for students to see it
6. Pull the stopper so the sachet falls into the H2O2, releasing the “genie”

ADDITIONAL COMMENTS:
Baquacil (27% H2O2) can be bought commercially at pool supply stores.

SAFETY:
Concentrated hydrogen peroxide can cause severe burns, so gloves should be worn and caution taken. Goggles should be worn at all times. The stopper on the flask should have at least one hole in it just in case the reaction were to go off there would be a pressure release to prevent a buildup of pressure in the flask. Also, the flask should not be stoppered for long.

REFERENCES:
Imreibe, Caroline. “Genie in a Bottle.” Elmhurst College: Demonstrations. Virtual Chembook, Elmhurst College, Accessed 28 Jul 2010. http://www.elmhurst.edu/~chm/demos/Geniebottle2.htm

STORY:
This demo can really be played off by telling the student you have a magic flask with a genie inside. You can also put your ear to the flask, telling them that you hear someone knocking on the glass and talking.

Handout

This problem set practices calculating moles from a volume and density, calculating the mass of product formed, and calculating the molecules of product formed.

This lesson plan‘s topic is stoichiometry. Genie in a Bottle is the hook for this lesson that has students calculating the amount of a reactant or a product in a chemical reaction.