Appendix C
Isopropyl Alcohol Combustion Demonstration
(modified from Flinn Scientific "Chem Fax: Woosh Bottle")
Materials:
5-gallon plastic water jug with cap
15 mL isopropyl alcohol
1 meter stick with candle attached at one end
25-mL graduated cylinder
1 match or lighter
Safety:
1. Wear heat resistant apron and goggles.
2. Always recap the alcohol bottle and move it away from the demonstration area.
3. Never perform this demonstration in a glass bottle. It may shatter and cause serious injuries.
4. Have a fire extinguisher ready in case of an accident.
Procedures for the demonstration
1. Measure out 15 mL of isopropyl alcohol and record the mass.
2. Add the isopropyl alcohol into the 5-gallon plastic jug. Recap the alcohol bottle and move it away from the demonstration area.
3. Place the cap onto the 5-gallon jug and slowly swirl the jug to allow the alcohol to spray over the entire interior surface. This allows the alcohol to vaporize inside the jug.
4. Open the cap and remove any excess liquids. Record the mass of the liquid.
5. Place the jug on a sturdy surface. Light the candle attached to the meter stick and carefully place the lit candle to the opening of the jug.
6. Students will observe a flame inside the bottle and hear a "whoosh" sound.
7. After the reaction, water will collect inside the bottle. Remove the water and record its mass.
Tips:
1. Always practice demos before demonstrating it in the classroom.
2. This demonstration works well in a dimly lit room.
3. Do not use the plastic jug immediately after the demonstration. The carbon dioxide must be allowed to escape out of the jug and the jug will be hot.
4. Students can write out the equation for the combustion of isopropyl alcohol and calculate the mass of water that should have been made. Using this information and the actual mass of the water from step 7, students can calculate percent yield and discuss sources of error.
Comments: