Organic Chemistry

• Homologous Series Properties

  Family of molecules with

  • Same general formula
  • Consecutive members differ by CH2
  • Similar chemical properties
  • Physical properties gradually changes.
• Saturated

  No Carbon-Carbon double or triple bonds
• Dextrorotatory (d)

  Plane of polarisation is rotated clockwise
• Levorotatory (l)

  Plane of polarisation is rotated anticlockwise
• Optical isomers are called enantiomers
• Enantiomers have 4 different functional groups.
• Electrophile

  Species that can accept an electron pair (to form a dative covalent bond)
• Nucelophile

  Species that donates an electron pair.
• Substitution reaction

  Replacement of a functional group by another
• Backwards of addition reaction is substitution reaction.
• (Free) radicals

  Atoms with unpaired electrons
• Homolytic fission

  Breaking apart of a covalent bond to form identical free radicals
• Heterolytic fission

  Breaking apart of covalent bond to form unique atoms
• Curly arrow

  Shows the movement of electrons

  • Double headed - two electrons moving
  • Single headed - one electron moving.
• General Formula

  Simplest algebraic formula of a member of a homologous series
• Structural Formula

  The minimal detail that shows the arrangement of atoms in a molecules
• Displayed formula

  The relative positioning of atoms and the bonds between them.
• Skeletal formula

  The simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups.
• Homologous series

  A series of organic compounds having the same functional group but with each successive member differing by CH2
• Functional group

  A group of atoms responsible for the characteristic reactions of a compound.
• Alkyl group


  Of formula CnH2n+1
• Aliphatic


  A compound containing carbon and hydrogen joined together in straight chains, branched chain, or non-aromatic rings.
• Aromatic


  A compound containing a benzene ring.
• Alicyclic

  An aliphatic compound arranged in non-aromatic rings with or without side chains.
• Saturated

  Single carbon-carbon bonds only
• Structural Isomerism

  Compounds with the same molecular formula but different structural formulae.
• Chain Isomerism

  When there are two or more ways of arranging the carbon skeleton of a molecule.
• Position Isomerism

  Same carbon skeleton and functional group, but the functional group is joined in a different place.
• Functional group

  Isomers with same molecular formula but different functional groups

  1. Aldehydes and Ketones
  2. Carboxylic Acids and Esters
  3. Alcohols and Ethers
• Stereoisomers

  Compounds with the same structural formula but with a different arrangement in space
• E/Z isomerism

  The restricted rotation about a carbon-carbon double bond.

  • Only occurs in alkenes which each carbon atom posses two different groups.
• Cis-trans isomerism

  A special case of E/Z isomerism which two of the substituent groups attached to each carbon atom of the C=C group are the same.
• Racemate/Racemic mixture

  A mixture of two equal amounts of enantiomers is optically inactive as the two effects cancel out.
• Enantiomers

  Have identical physical and chemical properties

  • Different reactions with other optically active substances
• Enzymes are stereospecific and can distinguish between two enantiomers

  • Will catalyse the reactions of one but not the other.
• Reactive site

  A region of higher or lower electron density.
• Nucleophiles

  Species that are electron-pair donors

  • Attack regions of low electron density
• Electrophiles

  Species that are electron-pair acceptors

  • Attack regions of high electron density.
• Substitution reaction

  Atom or group in a molecule is replaced by another.
• Addition reaction

  Two molecules add together to form one larger one.