SNC2D Demonstration - Bubbled Methane Combustion
Philip Loconte
Ministry Expectations
C3.4 - write word equations and balanced chemical equations for simple chemical reactions
(e.g., 2H2 + O2 -> 2H2O)
C3.5 - describe, on the basis of observation, the reactants in and products of a variety of chemical reactions, including synthesis,
decomposition and displacement reactions (e.g., reactions occurring when magnesium burns or in the production of oxygen from
hydrogen peroxide; the reaction of iron and copper sulphate; reactions occurring when fossil fuels burn)
Introduction and Background
Methane is a hydrocarbon gas that is less dense than air, causing it to rise. It is also flammable and can undergo a complete combustion
reaction in the presence of sufficient oxygen. In this demonstration, bubbles of methane will undergo a mixture of combustion reactions. This
reaction will be compared to the controlled combustion of methane gas via a bunsen burner. This demonstration can be used as an
interesting hook during the Types of Reactions section of the Grade 10 chemistry unit.
Materials
- 10 mL glycerol - 1000 mL beaker - 800
mL water - 100 mL liquid soap
- rubber tubing - bunsen burner - flint wooden splints
- Methane gas (from gas valve in the lab) -
matches
Safety and Disposal
Methane gas is flammable and extreme caution should be used at all times. Always check the gas valves for leaks and ensure the master
valve is closed before and after the demonstration. Students should be wearing goggles and should remain away from the teacher during the
demo. Students should not participate in this demonstration. Teachers performing this demo should be wearing goggles, sleeves rolled up,
hair tied back, hands wet and without jewellery or nail polish. Ensure a fire extinguisher is nearby.The liquid materials used in this
demonstration are safe for sink disposal.
Procedure
1. Attach and demonstrate the proper use of a bunsen burner
2. Close gas valve and detach bunsen burner
3. Add 800mL water, 100mL liquid soap and 10mL glycerol to the 1000mL beaker and mix gently
4. Fix rubber tubing to the valve and submerge the other end into the soapy solution
5. Open the gas valve and allow bubbles to form before closing gas valve
6. Wet hands and collect a small amount of bubbles and move away from the beaker
7. Have a student strike a match and light the splint
8. With the teacher’s arms extended, have the student touch the splint to the bubbles
Results - The lit splint will ignite the methane bubbles, generating an intense, yellow/orange flame in a quick reaction.
Explanation
The combustion of methane gas follows the formula: CH4 + 2O2 --> CO2 + 2H2O
This concept can also be connected to the STSE issue surrounding the burning of fossil fuels resulting in CO 2 (a known greenhouse gas)
being emitted into the atmosphere. Teachers may also describe the difference between the blue flame from the bunsen burner (complete
combustion) and the yellow flame from the demo (incomplete combustion).
Tips for Success/Teacher Notes
Safety is an absolute priority during this demonstration. If the class is not obeying the safety protocols of the lab, do NOT perform this demo.
Be sure to close the master valve upon completion of the demo. Dawn detergent works very well for the creation of bubbles. The
glycerol/glyerine helps bond with the hydrogen in the water, and reduce likelihood of evaporation and popping of the bubble.
1. References
Adam-Carr, C., Gabber, M., Hayhoe, C., Hayhoe, D., Hayhoe, K., & Sanader, M. (2010) Nelson Science Perspectives 10. Nelson Education Ltd.,
SNC2D Demonstration - Bubbled Methane Combustion
List some of the safety precautions taken before conducting this
demonstration.
Canada.
2. What did you observe from the combustion reaction using the bunsen
burner? (flame colour, size, heat, etc.)
3. What did you observe from the combustion reaction using the methane bubbles?
4. Provide the word, skeletal and balanced chemical equations for the complete combustion of methane.
Word equation: _____________________________________________________________
Skeletal equation: __________________________________________________________
Balanced equation: __________________________________________________________
5. How might the products of this reaction play a role in climate change and global warming?
6. Did the demonstration show the complete combustion of methane? If not, what might be happening?
7. How does this concept relate to the adjusting of the bunsen burner to get an optimal flame?
Philip Loconte