CAIE IGCSE Chemistry: Organic Chemistry

Organic Chemistry

• Organic Chemistry is the scientific study of the structure, properties, and reactions of organic carbon compounds.
• Suffixes are used to identify different types of compounds:
  • -ane: Alkane
  • -ene: Alkene
  • -anol: Alcohol
  • -anoic acid: Carboxylic acid
  • -yl/-anoate: Ester
• Homologous Series: a group of organic compounds with similar chemical properties, same functional group, and same general formula, differing from one member to the next by a CH2 unit.
• Essential Terminology:
  • Functional Group: an atom or group of atoms that determine the chemical properties of a homologous series.
  • Structural Isomers: compounds with the same molecular formula but different structural formula.
  • Saturated Compounds: molecules in which all carbon-carbon bonds are single bonds.
  • Unsaturated Compounds: molecules where one or more carbon-carbon bonds are not single.

Fuels

• Uses of different fractions of petroleum:
  • Naphtha: chemical feedstock
  • Kerosene/Paraffin: jet fuel
  • Diesel oil/Gas oil: fuel in diesel engines
  • Fuel oil: fuel in ships and home heating systems
  • Lubricating: lubricants, waxes, and polishes
  • Bitumen: making roads
• Complete Combustion: a complete combustion reaction with any organic compounds produces Carbon Dioxide and Water as its product.
• Incomplete Combustion: an incomplete combustion reaction with any organic compounds produces Carbon Monoxide and Water as its product.

Alkanes

• Alkanes: saturated hydrocarbons [single carbon bonds] that are generally unreactive, but they do undergo combustion reactions.
• General formula: CnH2n+2
• Examples: Methane (CH4), Ethane (C2H6), Propane (C3H8), Butane (C4H10)
• Substitution Reaction: alkanes undergo substitution reactions, where the atom of another element under UV light replaces the hydrogen atom.

Polymers

• Large molecules are built up from small units known as monomers.
• Monomers: a single unit of a substance.
• Polymers can have different linkages depending on the type of polymerization and monomer.
• Examples of polymers:
  • Polyester (PET)
  • Polyamide (e.g. Nylon)
  • Poly(ethene)
  • Protein (natural polyamide)

Carboxylic Acids

• General formula: CnH2n+1COOH
• Functional group: COOH
• Examples: Ethanoic Acid (CH3COOH), Methanoic Acid (CH2O2), Propanoic Acid (C3H6O2), Butanoic acid (C4H8O2)

Polymerisation

• Addition Polymerisation: occurs in monomers that contain double carbon (C=C) bonds, forms only a polymer molecule.
• Condensation Polymerisation: occurs when two different monomers are linked together with the removal of a smaller molecule, usually water.
• Examples of condensation polymerisation:
  • Nylon (polyamide) made from a dicarboxylic acid monomer and a diamine monomer.
  • PET (polyester) made from a dicarboxylic acid monomer and diols (alcohol with an -OH functional group).

Protein and Natural Polyamides

• Proteins are natural polyamides formed from amino acids monomers.
• General structure of amino acids:
• Proteins contain the same linkages (amide links) as nylon but with different units from amino acid monomers.