Chemical demonstration

The serpent

A great demonstration of the action of an inorganic catalyst on the rate of a chemical reaction is the "Serpent".
A very impressive reaction demonstrating  the action of a catalyst.
The ingredients for the serpent demonstration.

To conduct this activity you will need a:

- pneumatic trough

- Potassium iodide crystals

- 33% hydrogen peroxide

- Dishwashing liquid

- Green food dye.

- 100ml measuring cylinder

Place 20ml of hydrogen peroxide solution in the measuring cylinder. Add detergent (about 6 ml) and a few drops of green food dye. Place the mesuring cylinder in the trough and add a small spatula full of KI crystals.

Click to see a 120kb movie of the serpent.

The demonstration shows vividly the increase in the rate of the reaction represented by the equation


Fill the measuring cylinder. Is this reaction exothermic or endothermic?
Do the products contain more energy than the reactants?