Unit 1

• Organic chemistry


  The branch of chemistry that studies carbon compounds
• Catenation


  The ability of atoms of the same element to join together forming short or long chains and rings
• Functional group


  The part of a molecule or a compound that determines the chemical properties of that molecule or compound
• Common functional groups of organic compounds

  • Alkane
  • Alkene
  • Alkyne
  • Aromatic
  • Alcohol
  • Aldehyde
  • Ketone
  • Carboxylic acid
  • Ester
• Organic compounds are generally classified based on their functional group
• Hydrocarbons


  Organic compounds composed of the elements carbon and hydrogen only
• Saturated hydrocarbons


  Compounds of carbon and hydrogen containing only carbon-carbon single bonds
• Unsaturated hydrocarbons


  Compounds of carbon and hydrogen possessing one or more multiple bonds (double or triple bonds) between carbon atoms
• Detailed structure


  A formula that shows all the bonds and atoms
• Condensed structure


  A shorter structure
• Alkanes


  Saturated hydrocarbons containing chains of carbon atoms linked by single bonds only
• General formula of alkanes


  CnH2n+2, where n = 1, 2, 3...
• First ten alkanes


  • CH4
  • C2H6
  • C3H8
  • C4H10
  • C5H12
  • C6H14
  • C7H16
  • C8H18
  • C9H20
  • C10H22
• Alkanes differ from each other by a -CH2- group called the methylene group
• Homologous series


  A group of compounds in which each member differs from the next member by a -CH2- group
• Compounds in the same homologous series can be represented by the same general formula
• Isomerism is the way compounds having the same formula differ in the way their atoms are arranged
• Structural isomerism


  Isomerism where compounds have the same molecular formula but different structural formulas
• Possible structural isomers for C4H10, C5H12 and C6H14
• General method for the preparation of alkanes in the laboratory

  Decarboxylation method to prepare methane
• Biogas can be produced from cow dung
• Alkanes have low chemical reactivity due to the stability of carbon-carbon single bonds
• Key molecules required to build structures that enable organisms to function


  • n atoms
  • Complete Table 1.2
• Alkanes


  • Every carbon atom in the molecule forms four single covalent bonds with other atoms
  • Alkanes have the general formula CnH2n+2, where, n = 1, 2, 3 . . .
• Alkanes


  • CH4
  • C2H6
  • C3H8
• Homologous series


  A group of compounds in which each member of the group differs from the next member by a -CH2- group
• First ten members of the homologous series of straight-chain alkanes

  • Methane
  • Ethane
  • Propane
  • n-Butane
  • n-Pentane
  • n-Hexane
  • n-Heptane
  • n-Octane
  • n-Nonane
  • n-Decane
• As the number of carbon atoms increases


  The percentage by mass of hydrogen decreases and the physical state changes from gas to liquid to solid
• Petroleum related products


  • Solids
  • Liquids
  • Gases
• Intermolecular forces in alkanes


  Weak Van der Waal's forces, the strength of which increases with increasing surface area (molecular mass)
• As the number of carbon atoms increases

  The density, melting point, and boiling point of alkanes increase
• Branched-chain alkanes


  Alkanes containing chains with branches
• Normal or straight-chain alkanes


  Alkanes containing all the carbon atoms in one continuous chain
• In alkanes, each carbon atom is tetrahedrally bonded to four atoms with a bond angle of 109.5°
• In alkanes containing a continuous chain of carbon atoms, the carbon atoms are not linked in straight line but in zigzag chains
• Rules are important for naming organic compounds to have a simplified and systematic way of naming
• Prefixes in organic compound names

  Indicate the number of carbon atoms
• Suffixes in organic compound names

  Indicate the type of functional group present
• Prefixes for 1 to 10 carbon atoms

  • Meth-
  • Eth-
  • Prop-
  • But-
  • Pent-
  • Hex-
  • Hept-
  • Oct-
  • Non-
  • Dec-
• Common names of alkanes

  Use prefixes n-, iso-, and neo-