Introduction to Organic Chemistry

• 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
• Displayed formula


  Shows all the covalent bonds and atoms present in a molecule
• Shape around carbon atom in saturated hydrocarbons

  • Tetrahedral
  • Bond angle 109.5o
• Skeletal formula


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


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


  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
  • They show a gradual change in physical properties (e.g. boiling point)
  • Each member differs by CH2 from the last
  • Have same chemical properties
• Homologous series


  • Alkane
  • Alkenes
  • Alcohols
  • Halogenoalkanes
  • Aldehydes
  • Ketones
  • Carboxylic acids
  • Esters
• Precedence of functional groups

  Carboxylic acids > aldehydes > ketones > alcohols > alkenes > halogenoalkanes
• 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
• Naming carbon chains


  • 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
• Naming functional groups


  • 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 if they are needed to avoid ambiguity
• Naming with suffixes


  • 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
• Halogenoalkanes


  • Use the prefixes -fluoro, -chloro, -bromo, or –iodo
  • Give the position number if necessary
• Alcohols


  • Have the ending -ol
  • Add the position number for the OH group between the name stem and the –ol
• Alcohols with another functional group

  • The priority group gets the suffix ending and the OH can be named with the prefix hydroxy-
• Alcohols with multiple -OH groups


  • Use di, tri etc. and add the 'e' on to the stem name
• Alkenes


  • The suffix -en can go in front of other suffixes
  • The alcohol and carboxylic acid groups have higher priority than the alkene group so take precedence with numbering
• Alkenes with stereoisomers


  • Include E or Z at start to show the type of stereoisomer
• Alkenes with multiple double bonds

  • Suffix ends diene or triene
• Aldehydes


  • Name ends in –al
  • Always has the C=O bond on the first carbon of the chain
• Ketones


  • Name ends in -one
  • Need a number to show the position of the double bond if 5C's or more in a chain
• Carboxylic acids


  • Have the ending -oic acid
  • No number is necessary for the acid group as it must always be at the end of the chain
  • Numbering always starts from the carboxylic acid end
• Carboxylic acids with two groups

  • Called a - dioic acid
• Ketones with two groups

  • Di is put before –one and an e is added to the stem
• Aldehydes with two groups

  • Di is put before –al and an e is added to the stem
• Aldehydes


  An aldehyde's name ends in -al, it always has the C=O bond on the first carbon of the chain so it does not need an extra number
• Ketones


  Ketones end in -one, when ketones have 5C's or more in a chain then it needs a number to show the position of the double bond
• Carboxylic acids


  These have the ending -oic acid but no number is necessary for the acid group as it must always be at the end of the chain. The numbering always starts from the carboxylic acid end
• Diones


  If two ketone groups then di is put before -one and an e is added to the stem
• Dialdehydes


  If two aldehyde groups then di is put before -al and an e is added to the stem