oxidizers

Elephants Toothpaste

Oxidizers are like the big bully who takes your lunch money or electrons. They tend to beat up on others easily and cause havoc in the process. Hydrogen peroxide is used in many demonstrations and degrades to oxygen gas and water.

Concepts:

  • This is messy so be prepared...

  • Catalysts, decomposition reactions, oxygen enriched atmospheres

Safety:

  • Safety glasses

  • Nitrile gloves

  • Overhead obstructions

Equipment:

  • Dawn dish soap

  • Hydrogen Peroxide 30%, this will burn your skin if not careful

  • 250 ml beaker

  • 1,000 ml graduated cylinder or flask

  • Food coloring

  • Plastic tarp

  • Sodium iodide

Preparation:

  • Fill the beaker with 4 oz./120 ml of room temperature water

  • Add a table spoon of sodium iodide crystals and stir to dissolve, repeat until you have saturated the solution (No more dissolves)

  • Cover the table and possibly floor with plastic

  • Measure 2 ounces of 30% hydrogen peroxide (60 ml) and pour into the graduated cylinder or flask

  • Add a squirt of soap (5 ml) to the hydrogen peroxide

  • Add food coloring to the soap mixture

Demonstration Instructions

  • You have prepared the demo now all you have to do is add the saturated sodium iodide (Catalyst) to the soapy mixture.

  • Pour it in quickly and stand back, it will take about 3 seconds to react

Observations:

  • The decomposition of hydrogen peroxide into oxygen and water quickly fills the soapy matrix with gas and heat forcing out a frothy foam

Learning Outcomes:

  • Students will get to see an exothermic reaction and an oxidation-reduction reaction all in one. Hydrogen peroxide reacts with soap and a catalyst to create a huge plume of foam that resembles toothpaste being squeezed out of a tube.

  • In the adult version, 10, 20, or 30% hydrogen peroxide reacts with sodium iodide as the catalyst. The addition of the catalyst allows the hydrogen peroxide to break down into oxygen gas and water. While the reaction is going on, the oxygen gas being released forms bubbles in the soap resulting in a tube of bubbles leaving a graduated cylinder.

  • The reaction also heats up meaning this is an exothermic reaction. When reactions take place and bonds are broken or created, the bond energies for the reactants and products are a factor in whether the reaction releases or consumes energy. In this experiment, the bond energies of the products (water and oxygen) are much greater than that of the reactant (hydrogen peroxide). This means the reaction releases energy and is measured in the form of heat.

  • You can also take a wooden splint and light it, blow it out so it smolders and put it in the bubble space and it will reignite with the oxygen enriched environment..

Chemical Disposal:

  • Dispose of according to local regulations. Use generator knowledge to make a waste determination.

Additional Information: