Summary
Fuels are substances that release energy when burned, and they are primarily derived from fossil fuels like coal, oil, and natural gas. These fuels are non-renewable and contribute to air pollution and global warming when burned.
- Fossil Fuels — natural substances formed from the remains of ancient organisms. Example: Coal, oil, and natural gas are common fossil fuels.
- Complete Combustion — occurs when a fuel burns in plenty of oxygen, producing carbon dioxide and water. Example: Propane burning in a well-ventilated area.
- Incomplete Combustion — occurs when there is not enough oxygen, producing carbon monoxide, soot, and water. Example: A car engine running in a closed garage.
- Cracking — a process that breaks down large hydrocarbons into smaller, more useful ones. Example: Producing gasoline from larger oil molecules.
Exam Tips
Key Definitions to Remember
- Fossil Fuels: Natural substances formed from ancient organisms.
- Complete Combustion: Burning with enough oxygen to produce CO2 and H2O.
- Incomplete Combustion: Burning with insufficient oxygen, producing CO and soot.
Common Confusions
- Confusing complete and incomplete combustion products.
- Misunderstanding the environmental impact of fossil fuels.
Typical Exam Questions
- What is the process of separating different length hydrocarbons from crude oil? Fractional Distillation
- What are the two products of complete combustion? Water and carbon dioxide
- Why is cracking necessary? To meet the demand for shorter chain hydrocarbons.
What Examiners Usually Test
- Understanding of combustion processes and their products.
- Knowledge of the environmental impact of burning fossil fuels.