Basic Concepts of Organic Chemistry

Presenter: Chris Harris from Allery Chemistry (Aller Tutors)

Purpose:

• Overview of OCA (Organic Chemistry A) for revision purposes
• Slides available for purchase via link in the description
• Matches syllabus specification points

Types of Formula

• General Formula: Algebraic formula for a chemical family (e.g., Alkanes, Alkenes, Alcohols)

  • Alkanes: CnH2n+2
  • Alkenes: CnH2n
  • Alcohols: CnH2n+1O

• Molecular Formula: Exact number of atoms (e.g., Ethane: C2H6)

• Empirical Formula: Simplest whole number ratio of atoms (e.g., Ethane: CH3)

• Structural Formula: Arrangement of atoms without all bonds (e.g., Butan-1-ol)

• Skeletal Formula: Shows carbon skeleton and functional groups, not hydrogen and carbon atoms

• Displayed Formula: Shows arrangement and all bonds within the molecule

Homologous Series

• Group of compounds with same functional group and general formula
• Successive members differ by CH2
• Examples:
  • Alkanes (end in -ane)
  • Alkenes (end in -ene)
  • Alcohols (end in -ol)
  • Aldehydes (end in -al)
  • Ketones (end in -one)
  • Carboxylic acids (end in -oic acid)
  • Halogenoalkanes (prefix: fluoro-, chloro-, bromo-, iodo-)
  • Cycloalkanes (start with cyclo-)
  • Esters (end in -anoate)

Carbon Skeleton Types

• Aromatic Compounds: Contain benzene ring
• Aliphatic Compounds: Straight or branched
• Alicyclic Compounds: Rings that are not aromatic

Naming Molecules (IUPAC Rules)

1. Count longest carbon chain (stem): methane, ethane, propane, etc.
2. Identify functional group (suffix)
3. Number chain for lowest position of functional group
4. Side chains and less important groups as prefixes

Mechanisms

• Curly Arrows: Show movement of electron pairs
• Free Radical Mechanisms: No curly arrows needed
• Bond Fission:
  • Heterolytic Fission: Unequal electron distribution
  • Homolytic Fission: Equal electron distribution

Structural Isomers

• Chain Isomerism: Different carbon skeleton arrangements
• Positional Isomerism: Different position of functional group
• Functional Group Isomerism: Different functional groups

Importance of Correct Representation

• Use longest continuous chain for accurate isomer representation

Conclusion

• Provides a broad overview of organic chemistry's basic concepts
• Slides available for detailed study and revision
• Encouragement to subscribe for updates on new educational content