Elephant Toothpaste Lab

In the Elephant Toothpaste Lab you and your lab partner will demonstrate that you can measure the rate of oxygen production from hydrogen peroxide.  You will do this by mixing soap and potassium iodide into hydrogen peroxide using the following recipe.

Chemical	Amount Used
Hydrogen Peroxide	10 mL
Dish Soap	0.5 mL
Potassium Iodide	1 mL

Combine the ingredients above in order. Once you add the Potassium Iodide, start the timer and record the amount of time it takes to rise up the graduated cylinder. Measure the height of the column every 10 seconds.

Repeat this 3 times. Once you have done the above combination 3 times you will be able to change one of the variables above to see how it affects the time it takes to react.

How will you decide which change to make?  Recall that two particles of hydrogen peroxide must collide in order to react.  When these two particles collide, they release oxygen gas and turn into water molecules.  This process is summarized using the following equation.

2 H₂O₂   -->    2 H₂O    +    O₂