Hydrocarbons

Rucete ✏ Chemistry In a Nutshell

1. What Are Hydrocarbons?

• Hydrocarbons are organic compounds made of only carbon and hydrogen.
• They serve as the foundation for all organic compounds.
• Classified as:
  • Aliphatic hydrocarbons (straight or branched chains)
  • Aromatic hydrocarbons (contain benzene rings)

2. Types of Hydrocarbons

Saturated Hydrocarbons (Alkanes)

• Only single bonds between carbon atoms.
• General formula: C_nH_2n+2
• Examples:
  • CH₄ (methane)
  • C₂H₆ (ethane)
  • C₃H₈ (propane)
  • C₄H₁₀ (butane)

Unsaturated Hydrocarbons

• Contain double or triple bonds.

Alkenes

• One or more double bonds.
• General formula: C_nH_2n
• Example: C₂H₄ (ethylene), C₃H₆ (propylene)

Alkynes

• One or more triple bonds.
• General formula: C_nH_2n-2
• Example: C₂H₂ (acetylene)

3. Cyclic Hydrocarbons

• Hydrocarbons that form rings.
• General formula for cycloalkanes: C_nH_2n
• Examples:
  • Cyclopropane (C₃H₆)
  • Cyclobutane (C₄H₈)
  • Cyclopentane (C₅H₁₀)

4. Aromatic Hydrocarbons

• Contain benzene rings (C₆H₆).
• Highly stable due to resonance.
• Substitution patterns:
  • Ortho (o-): adjacent positions
  • Meta (m-): separated by one carbon
  • Para (p-): opposite positions

5. Hydrocarbon Naming

• Prefixes based on number of carbons:
  • Meth- (1), Eth- (2), Prop- (3), But- (4), Pent- (5), Hex- (6), Hept- (7), Oct- (8), Non- (9), Dec- (10)
• Suffixes based on bond types:
  • -ane (alkanes), -ene (alkenes), -yne (alkynes)