Summary
Bubbles filled with methane rise when released. The rising bubbles are set on fire with a candle on a stick to demonstrate the combustion reaction.
Hazards
Methane gas is flammable.
Chemicals and Solutions
- Bubble Solution
- Methane source
Materials
- Glass funnel with long stem
- Large crystallizing dish
- Long stick with candle attached
- Matches
- Methane gas outlet
- 2-3 feet of amber tubing
Procedure
- Place the soap solution in the crystallizing dish.
- Attach one end of the tubing to the gas outlet and the other end to the stem of a funnel.
- Place the mouth of the funnel into the soap solution.
- Light the candle and hold the stick in one hand.
- With the other hand, turn the gas on low such that bubbles form slowly.
- Once the inside of the funnel is coated with soap, remove the funnel from the soap solution and hold it such that the mouth points upward. Once you have a large bubble, shake it loose from the funnel. As the bubble rises, try to ignite it with the candle.
Hint: Be careful to release the bubbles before lighting, or the funnel will catch fire. If the funnel does catch fire, turn off the methane to extinguish.
Discussion
\( \ce{ CH4_{(g)} + 2O2_{(g)} -> 2H2O_{(g)} + CO2_{(g)} ~~~~ \Delta G^{{o}}_{Rxn} = -801.1 KJ/Mol } \)
Disposal
The soap solution can be reused.