Elephant Toothpaste

Question What will be the reaction when hydrogen peroxide, yeast, soap and catalysts are mixed together?

Hypothesis I predict that the hydrogen peroxide, potassium iodide & yeast will have a chemical reaction which will be a foamy substance.

Materials

§ Hydrogen peroxide (30%) - 25 mL

§ Potassium iodide solution- 3.3 g

§ Yeast- .3 g

§ Liquid soap

§ Food coloring

§ Jar

§ Graduated cylinder

§ Safety glasses

§ Rubber gloves

§ Tissues

Background Research

The chemical explanation for this experiment is it shows the decomposition of hydrogen peroxide catalyzed by potassium iodide. Hydrogen peroxide decomposes into water and oxygen gas, but normally the reaction is too slow to be easily perceived or measured:

2H₂O₂ → 2H₂O_(l) + O_2(g)

The iodide ions from potassium iodide acts as a catalyst—it speeds up the reaction. The iodide ion changes the mechanism, by which the reaction occurs as:

Oxygen quickly leaves causing strong foaming from the soap. Steam rising from the foam shows that the reaction is exothermic . Minimum quantities of iodine are being liberated and can be detected by its color if the experiment is done without dyes.

Procedure

1. First put on your safety glasses and gloves.

2. Measure 25 mL of the 30% hydrogen peroxide into a graduated cylinder.

3. Mix .3 grams of yeast and 3.3 potassium iodide into a graduated cylinder.

4. Add a squirt of dish soap and food coloring into the jar.

5. Add the 30 % hydrogen peroxide into the jar.

6. Last add the .3 g of yeast and 3.3 potassium iodide into the jar.

Results

The result was a foamy substance.

Safety Regulations

This substance is severely corrosive to the skin, eyes, and respiratory tract. Sodium iodide is slightly toxic by ingestion. Safety glasses must be worn at all times during the experiment.