Screaming Gummy Bear
Introduction:
The “Screaming Gummy Bear” experiment demonstrates the large quantity of energy produced from
the oxidation reaction of carbohydrates. This reaction produces large quantities of energy in the form of light.
Ministry Expectations Addressed: SCH 3U:
C2.2 write balanced chemical equations to represent synthesis, decomposition, single displacement, double displacement,
and combustion reactions, using the IUPAC nomenclature system.
C2.3 investigate synthesis, decomposition, single displacement, and double displacement reactions, by testing the products
of each reaction (e.g., test for products such as gases, the presence of an acid, or the presence of a base).
C2.4 predict the products of different types of synthesis and decomposition reactions (e.g., synthesis reactions in which
simple compounds are formed; synthesis reactions of metallic or non-metallic oxides with water; decomposition reactions,
in which a chemical compound is separated into several compounds).
C3.1 identify various types of chemical reactions, including synthesis, decomposition, single displacement, double
displacement, and combustion.
C3.2 explain the difference between a complete combustion reaction and an incomplete combustion reaction (e.g.,
complete and incomplete combustion of hydrocarbon fuels)
Reactions:
There are two reactions that occur in this experiment.
First, a decomposition reaction occurs. As potassium chlorate is heated, it decomposes into potassium
chloride and an excess of oxygen.
2KClO3(s) + heat → 2KCl(s) + 3O2(g)
Second, an oxidation reaction occurs when the carbohydrate is oxidized with the large quantity of
oxygen to produce carbon dioxide, water, and a large amount of energy in the form of light. The colour of the
light will be purple – this is the result of the potassium ion burning.
C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2O(g) + light
Materials:
7g Potassium Chlorate (KClO3(s))
Gummy bears
Test tube (25 X 150mm)
Test tube clamp
Retort stand
Eye goggles
Flint spark lighter
Plastic/glass shield
Tongs
Spatula/scoopula
Bunsen burner
Safety Precautions:
1.
2.
3.
4.
Wear safety goggles and put up a plastic safety shield.
Potassium chlorate should be used with caution. It is a strong oxidizing agent, especially when
molten. Keep all combustible materials away from the reaction area.
Make sure the test tube is pointed away from the audience.
This should be done in a well-ventilated room, or, preferably, in a fume hood.
Procedure:
1.
2.
3.
4.
5.
Set up the stand and clamp, and support the test tube in the clamp in a vertical position (slightly
tilted to the side).
Measure 5 -7 grams of potassium chlorate and add into the test tube.
Light the Bunsen burner. Gently heat the tube with the burner until the potassium chlorate is
completely molten. Bubbles of oxygen will begin to form.
Remove the Bunsen burner and turn off the heat source.
Use crucible tongs to drop in the gummy bear, and stand back!
Disposal:
Potassium chlorate decomposes to potassium chloride and oxygen. Potassium chloride is not toxic and can be
washed down the sink in small quantities.
Screaming Gummy Bear Worksheet
Name: ________________________________
1.
What is a decomposition reaction?
2.
Write a balanced reaction for the decomposition of potassium chlorate.
3.
How could we test for the presence of oxygen in this decomposition reaction?
4.
Why is it necessary to heat this reaction?
5.
Is this reaction an endothermic or an exothermic reaction? Explain your choice.
6.
Write a balanced reaction for the oxidation of glucose. Show which substance is reduced
and oxidized in the reaction. Also state the oxidizing agent and the reducing agent.
7.
Think back to the products of the reaction. Was this incomplete or complete combustion?
Did the reaction go to completion, forming only CO2 and H2O? What would the products
include if the combustion was incomplete?