Summary
Alkanes are saturated hydrocarbons with single covalent bonds, making them generally unreactive except in combustion and substitution reactions. They belong to a homologous series with the general formula CnH2n+2, where each member differs by a -CH2- unit and displays a trend in physical properties.
- Alkane — a saturated hydrocarbon with single bonds only. Example: Methane (CH4) is the simplest alkane.
- Saturated Compound — a compound with only single carbon-carbon bonds. Example: Ethane (C2H6) is a saturated compound.
- Substitution Reaction — a reaction where one atom is replaced by another. Example: Methane reacts with chlorine in UV light to form chloromethane.
Exam Tips
Key Definitions to Remember
- Alkanes are saturated hydrocarbons with single bonds.
- The general formula for alkanes is CnH2n+2.
Common Confusions
- Confusing saturated with unsaturated compounds.
- Misunderstanding the difference between substitution and addition reactions.
Typical Exam Questions
- What is the general formula for alkanes? CnH2n+2
- How do alkanes react with bromine water? Alkanes do not react with bromine water; it remains orange.
- What happens in a substitution reaction with halogens? A hydrogen atom is replaced by a halogen atom.
What Examiners Usually Test
- Understanding of the general formula of alkanes.
- Ability to identify saturated hydrocarbons.
- Knowledge of substitution reactions involving alkanes.