Acetylene Gas

Acetylene gas is an experiment used to demonstrate an incomplete combustion. The calcium carbide reacts with the water to create Acetylene Gas, which is explosive (yay). This experiment creates a loud POP and a LOT of soot.

Acetylene Gas: 

Special Glassware (in buskers kit), Water, Calcium carbide, matches,  Bucket (for disposal)

Measurements for experiment:

Things to say:

CaC2 + 2h20 --> C2H2 + Ca(OH)2

C2H2 (ethyne) + o2 --> 

Ethyne, better known by its trivial name acetylene, burns, but how cleanly it burns depends on availability of oxygen. Ever seen or used an acetylene torch used for welding/cutting metal. When you light up the torch, you only provide the flame with acetylene and it burns with a yellow flame and produces lots of soot:

C2H2(g) + O2(g) → CO(g) + H2O(g) + C(s) + heat (1)

Then you add oxygen and the flame turns blue-white and extremely hot:

2 C2H2(g) + 5 O2 → 4 CO2(g) + 2 H2O(g) + lots of heat (2)

• calcium carbide breaks down in water, to produce acetylene gas and calcium hydroxide.

• Acetylene gas is a hydrocarbon, It is an alkyne known as ethyne, eth- meaning two carbons, -yne meaning there's a triple bond.

• Alkynes are used for making plastics, miners torches and welding.

• Acetylene gas is often used for welding, because when enough oxygen is added it releases a lot of energy, creating a white hot flame.

• Acetylene Gas is highly flammable.

• Incomplete combustion.

• You can possibly see soot around sides of the glass. (maybe carbon)

• Cool thing about this reaction is that the gas keeps being produced until there's no calcium carbide left

• What is an incomplete combustion

• Only partial burning of the fuel

• Visible byproducts of the reaction, carbon and carbon monoxide.

NOTES

• Complete combustion happens when there is a good supply of air. Carbon and hydrogen atoms in the hydrocarbon fuel react with oxygen in an exothermic reaction:

• carbon dioxide and water are produced

• energy is given out

Carbon dioxide is an atmospheric pollutant. Incomplete combustion produces other pollutants.

Incomplete combustion happens when the supply of air or oxygen is poor. Water is still produced, but carbon monoxide and carbon are produced. Less energy is released than during complete combustion.

For example, here is one possible equation for the incomplete combustion of propane:

propane + oxygen → carbon + carbon monoxide + water

C3H8 + 3O2 → C + 2CO + 4H2O

Soot

The carbon is released as fine black particles. We see this in smoky flames, and it is deposited as soot.