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SCH 4U: Organic Chemistry
Teacher Demo: Burning Money
Topics
Exothermic reactions
Combustion reactions
Chemical properties of alcohols
Timing
preparation: 5 minutes
demonstration/activity: 10 minutes
Specific Expectations SCH4U
Introduction
Teachers are required to have fire safety training and permission of the employer
before going forward with this demonstration.
The purpose of this demonstration is to illustrate an example of an exothermic reaction
while looking at chemical properties of an alcohol. In this demonstration, a paper bill
(Canadian or US or play money) of any denomination is lit on fire but it remains intact.
The same is then done with a medical alcohol disinfectant pad.
Materials
isopropyl alcohol (rubbing alcohol) 50% V/V solution (if a
higher concentration, it can be diluted down with water)
water
two 250 mL beakers
Bunsen burner
spark igniter
crucible tongs
Canadian or US or other paper money bill (any
denomination)
alcohol disinfectant pads (optional)
safety goggles
flame resistant gloves
bucket of sand
fire extinguisher
Safety Considerations
Safety glasses should be worn. Isopropyl alcohol is extremely flammable. Any container
containing isopropyl alcohol must be kept away from any open flame.
Perform this reaction in a fume hood. A safety shield does not provide sufficient isolation.
This demonstration has significant fire potential. Any dripping of the alcohol could cause
the flame to shoot out at the teacher or students. No paper or books should be anywhere
near where this demonstration is occurring.
Hazardous Materials Identification System Rating
(0-minimal 1-slight 2-moderate 3-serious 4-severe)
Isopropyl alcohol
HMIS (0 to 4)
Health
3
Fire
3
Hazard
Reactivity
0
Procedure
Preparation
1. Make approximately 100 mL of a 50% volume/volume solution of isopropyl
alcohol and place in a 250 mL beaker. Place this on the bench outside the fume
hood.
2. Half fill the second beaker with tap water. Place this in the fume hood.
3. Set up the Bunsen burner.
Predict/Explain
4. Outline the key steps of the demonstration.
5. Organize the class into groups of 2-4 students. Ask each group to predict what
will happen when a paper money bill is placed in a flame. Each group should also
attempt to come up with a rationale for their prediction.
Observe
6. Conduct the demonstration using a paper bill. You may consider asking for a
student to volunteer a bill.
7. Ignite the Bunsen burner in the fume hood.
8. Outside of the fume hood, use the tongs to dip the bill in the alcohol mixture,
completely covering the bill with the solution.
9. Outside of the fume hood, use the tongs to remove the bill from the solution,
ensuring it is flat, and allowing any excess solution to drip back into the beaker.
10. Move the beaker with the alcohol fuel solution away from the fume hood, keeping
the beaker with water near the Bunsen burner.
11. Place the bill in the Bunsen burner flame for a few seconds, and then remove it.
Submerge it in the beaker of water if necessary.
12. Provide time for students to record their observations.
Explain
13. Ask the groups to reconvene and revise their explanations, if necessary.
Disposal
The alcohol solution can be used several times as long as it is stored in a sealed container
that has an appropriate workplace label.
Dispose of this organic solvent solution following the protocol outlined by the employer
and consistent with the municipality.
What happens?
The alcohol soaked bill will ignite into a large yellow flame.
As the alcohol is consumed, the flame will extinguish, leaving the bill intact.
It is possible for the paper to ignite. The beaker of water provides a way to salvage the bill
before significant damage is done.
How does it work?
The isopropyl alcohol, like other alcohols, is extremely flammable and has a relatively
low autoignition point (around 399oC). The autoignition point of paper is slightly higher
(451oC). Since the alcohol mixture is 50% water and water has a high specific heat
capacity, it absorbs some of the heat from the combustion reaction. Since there is not
enough heat present to evaporate the water, the bill will absorb the water and not burn.
Disinfecting alcohol pads also contain isopropyl alcohol and can be used in place of paper
money that the teacher then dips in an alcohol solution.
Teaching Suggestions/Hints
1. CAUTION: Students should NOT perform this work.
2. Ensure there are no open containers of any form of alcohol anywhere near the Bunsen
burner flame.
3. Any denomination of Canadian or US or artificial paper money will work. The bill
will air dry with no damage. If the same bill is used repeatedly, it may change
consistency over time and harden slightly.
4. The older Canadian bills work well, but the new polymer-based bills do not work.
5. The 50% solution of isopropyl alcohol may be used repeatedly if stored in a sealed
container.
6. The same demonstration can be extended using a disinfectant alcohol wipe pad
instead of paper money.
Next Steps
This demonstration can be used to introduce the concept of exothermic reactions and/or
chemical properties of organic compounds. It can also be used to review the concept of
combustion reactions from SCH 3U.
Additional Resources
A great demonstration example and video from Steve Spangler Science:
http://www.stevespanglerscience.com/lab/experiments/burning-money
Specific Expectations
SCH4U
A1.1 formulate relevant scientific questions about observed relationships, ideas,
problems, or issues, make informed predictions, and/or formulate educated
hypotheses to focus inquiries or research
B.2.4 analyse, on the basis of inquiry, various organic chemical reactions (e.g.,
production of esters, polymerization, oxidation of alcohols, multiple bonds in an
organic compound, combustion reactions, addition reactions)
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