intro

• Hydrocarbon

  Compound consisting of hydrogen and carbon only
• Molecular formula

  Formula which shows the actual number of each type of atom
• Unsaturated


  Contains a C=C double bond
• Saturated


  Contain single carbon-carbon bonds only
• General formula

  Algebraic formula for a homologous series e.g. CnH2n
• Empirical formula

  Shows the simplest whole number ratio of atoms of each element in the compound
• 3.1 Organic: Basic Concepts
• Displayed formula

  Show all the covalent bonds and atoms present in a molecule
• When drawing organic compounds add the hydrogen atoms so that each carbon has 4 bonds
• The shape around the carbon atom in saturated hydrocarbons is tetrahedral and the bond angle is 109.5o
• Skeletal formula

  Shows the simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups
• Structural formula

  Shows the minimal detail that shows the arrangement of atoms in a molecule
• Functional group

  An atom or group of atoms which when present in different molecules causes them to have similar chemical properties
• Homologous series

  Families of organic compounds with the same functional group and same general formula
• Homologous series show a gradual change in physical properties (e.g. boiling point)
• Each member of a homologous series differs by CH2 from the last
• Members of a homologous series have the same chemical properties
• Homologous series

  • Alkane
  • Alkenes
  • Alcohols
  • Halogenoalkanes
  • Aldehydes
  • Ketones
  • Carboxylic acids
  • Esters
• Prefix / suffix

  Used to name functional groups in organic compounds
• When compounds contain more than one functional group, the order of precedence determines which groups are named with prefix or suffix forms
• The highest precedence group takes the suffix (and the lowest number on the carbon chain), with all others taking the prefix form
• Double and triple C-C bonds only take suffix form
• Order of priority highest first

  • Carboxylic acids
  • aldehydes
  • ketones
  • alcohols
  • alkenes
  • halogenoalkanes
• Count the longest carbon chain and name appropriately
• Find any branched chains and count how many carbons they contain
• Add the appropriate prefix for each branch chain
• The position of the functional group on the carbon chain is given by a number – counting from the end of the molecule that gives the functional group the lowest number
• For aldehydes, carboxylic acids & nitriles, the functional group is always on carbon 1
• We only include numbers, however, if they are needed to avoid ambiguity
• Words are separated by numbers with dashes, numbers are separated by commas
• If there is more than one functional group or side chain, the groups are listed in alphabetical order (ignoring any di, tri)
• If the suffix starts with a vowel- remove the –e from the stem alkane name
• If the suffix starts with a consonant or there are two or more of a functional group meaning di, or tri needs to be used then do not remove the the –e from the stem alkane name
• The functional groups take precedence over branched chains in giving the lowest number
• Naming examples

  • 3-bromo-1-fluoropentane
  • 2,2-dichloro-1-fluorobutane
  • 2,3-dibromopentane
  • trichloromethane
• Where there are two or more of the same groups, di-, tri- ,tetra-, penta- or hexa- are used
• Halogenoalkanes

  Class the halogen as a substituent on the C chain and use the prefixes -fluoro, -chloro, -bromo, or –iodo
• Halogenoalkane examples

  • 2-bromobutane
• Alcohols

  These have the ending -ol and if necessary the position number for the OH group is added between the name stem and the –ol
• Alcohol examples

  • Butan-2-ol
  • 2-hydroxypropanoic acid
  • Ethane-1,2-diol
  • propane-1,2,3-triol