Intro to Organic Chemistry

• General formula


  Algebraic formula that can be applied to chemicals in a family
• Molecular formula


  The actual number of atoms in a molecule or element
• Empirical formula


  The simplest whole number ratio of atoms in a compound
• Structural formula


  The arrangement of atoms in a molecule without showing any bonds
• Skeletal formula


  Shows the carbon skeleton with functional groups, but no hydrogen atoms
• Displayed formula


  Shows the arrangement of all atoms and bonds in a molecule
• Homologous series


  A group of compounds with the same functional group and general formula
• Successive members of the same homologous series increase by CH2
• Types of homologous series

  • Alkanes
  • Alkenes
  • Alcohols
  • Aldehydes
  • Ketones
  • Carboxylic acids
  • Haloalkanes
  • Cycloalkanes
• Nomenclature


  The system for naming molecules, following IUPAC rules
• Steps for naming molecules

  1. Find the longest continuous carbon chain (stem name)

  2. Identify the functional group (suffix)

  3. Number the carbon chain so the functional group is on the lowest number

  4. Write any side chains as prefixes in alphabetical order

  5. Use di, tri, tetra etc. for multiple identical functional groups or side chains
• Mechanism


  Shows the movement of electrons during a chemical reaction
• Curly arrow mechanism


  • Curly arrows show the movement of a pair of electrons
  • Arrows start from an area with lots of electrons (e.g. double bond, lone pair)
  • The end of the arrow shows where the electrons are moving to or a new bond forming
• Free radical mechanisms do not use curly arrows
• Formation of a new bond

  1. Electrons moving from a lone pair to a bond

  2. Electrons moving from a bond to another atom
• Free radical mechanisms don't require curly arrows
• Free radicals can be found in the halogen or alkanes topics but don't need to be known for this
• Mechanism of OHA reaction with bromoethane

  1. Lone pair electrons move to bond with carbon

  2. Bond between carbon and bromine breaks, electrons move to bromine
• The final product is an alcohol and a bromide ion
• Sodium hydroxide is a spectator ion that doesn't get involved in the reaction
• Structural isomers


  Molecules with the same molecular formula but different structural formula
• Types of structural isomers

  • Chain isomers
  • Positional isomers
  • Functional group isomers
• Chain isomers


  Same molecular formula but different arrangement of the carbon skeleton
• Chain isomers


  • Pentane
  • 2-methylbutane
• Positional isomers


  Same molecular formula but different position of the functional group on the carbon skeleton
• Positional isomers


  • Pentan-1-ol
  • Pentan-2-ol
• Functional group isomers


  Same molecular formula but different functional group
• Functional group isomers


  • Pentane
  • Cyclopentane
• Stereoisomers (E/Z isomers)


  Same structural formula but different arrangement of atoms in space around a C=C double bond
• Stereoisomers have restricted rotation around the C=C double bond
• E/Z notation


  • E (from German 'entgegen') - different groups on opposite sides of the double bond
  • Z (from German 'zusammen') - same groups on the same side of the double bond
• Assigning E/Z configuration


  1. Identify the two different substituents on each carbon of the double bond

  2. Assign priority to substituents based on atomic number

  3. If the two highest priority substituents are on opposite sides, it is E

  4. If the two highest priority substituents are on the same side, it is Z
• When substituents have the same priority, look further down the carbon chain to determine priority
• The longest continuous carbon chain determines the parent structure, regardless of shape