Combustion of Hydrocarbons

What is combustion?

A chemical reaction in which a substance reacts with oxygen and releases energy.

What is complete combustion?

Combustion in a sufficient supply of oxygen.

What products form during complete combustion of hydrocarbons?

Carbon dioxide and water.

What is the word equation for complete combustion of a hydrocarbon?

Hydrocarbon + oxygen → carbon dioxide + water.

What is the balanced equation for complete combustion of methane?

CH₄ + 2O₂ → CO₂ + 2H₂O.

What is the balanced equation for complete combustion of ethane?

2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O.

What is the balanced equation for complete combustion of propane?

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O.

What is the balanced equation for complete combustion of butane?

2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O.

Why is complete combustion exothermic?

It transfers energy to the surroundings.

What is incomplete combustion?

Combustion occurring when there is insufficient oxygen.

What products can form during incomplete combustion?

Carbon monoxide and/or carbon (soot), together with water.

What is the word equation for incomplete combustion producing carbon monoxide?

Hydrocarbon + oxygen → carbon monoxide + water.

What is the word equation for incomplete combustion producing soot?

Hydrocarbon + oxygen → carbon + water.

Why does incomplete combustion occur?

There is insufficient oxygen for all carbon atoms to form carbon dioxide.

Why is carbon monoxide dangerous?

It binds strongly to haemoglobin, reducing the blood's ability to transport oxygen.

Why is carbon monoxide particularly hazardous?

It is a colourless, odourless, toxic gas.

Why is soot harmful?

It contributes to particulate air pollution and respiratory problems.

Why is complete combustion generally preferable?

It releases more energy per mole of fuel and avoids producing carbon monoxide and soot.

How can carbon dioxide produced by combustion affect the environment?

It contributes to the enhanced greenhouse effect and climate change.

Why can burning hydrocarbon fuels cause pollution?

Combustion can produce carbon dioxide, carbon monoxide, particulates and nitrogen oxides.