Definitions

• Alicyclic


  An aliphatic compound arranged in non-aromatic rings with or without side chains (branches)
• Aliphatic


  A compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings
• Alkyl group


  Group of formula CnH2n+1
• Aromatic


  A compound containing at least one benzene ring

  
• Displayed formula


  A formula which shows the relative positions of all the atoms and the bonds between them
• Functional group


  The reactive part of an organic molecule/the part of an organic molecule which gives it its characteristic properties or reactions
• General formula


  The simplest algebraic formula for a homologous series e.g. CnH2n+2

  for the alkanes
• Homologous series


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


  A compound containing Carbon and Hydrogen ONLY
• Saturated


  A compound containing single carbon-carbon bonds only
• Unsaturated


  A compound containing multiple carbon-carbon bonds including C=C, C≡C and aromatic rings
• Skeletal formula


  A simplified formula with hydrogen atoms removed from alkyl chains, leaving just a carbon skeleton drawn as a zig-zag and associated functional groups
• Structural Formula


  A formula showing the minimal detail for the arrangement of atoms in a molecule e.g. CH3CH2CH2CH2CH3 or CH3(CH2)3CH3
• Volatility


  The ease with which a liquid turns into a gas
• Free Radical (Radical)


  A species containing an unpaired electron
• Homolytic fission


  The breaking of a covalent bond and one of the bonded electrons going to each atom producing 2 free radicals
• Initiation


  The first step in free radical substitution where free radicals are made by uv radiation
• Propagation


  The second step in free radical substitution mechanism occurring in two repeated steps where new free radicals are made
• Structural Isomers


  Molecules with the same molecular formula but with different structural arrangements of atoms
• Substitution Reaction


  A reaction where an atom or group of atoms is replaced with a different atom or group of atoms (2 become 2 etc.)
• Termination


  The final step in free radical substitution where 2 radicals combine to form a stable molecule
• Addition Polymerisation


  The process by which many identical monomers are added one at a time to form a very long saturated molecule
• Addition Reaction


  A reaction where a reactant is added to an unsaturated molecule to make one saturated molecule (2 become 1 etc.)
• Biodegradable


  A material which is broken down naturally by living organisms
• Carbocation


  An organic ion where the carbon has a + charge
• Curly arrow


  The symbol used in an organic mechanism to show the movement of a pair of electrons
• Electrophile


  An atom or group of atoms which accepts a pair of electrons to form a new covalent bond
• Heterolytic fission


  The breaking of a covalent bond and both of the bonded electrons going to one atom producing a cation (+) and anion (-)
• Hydration


  A reaction in which a substance combines with water
• Monomer


  A small molecule which combines many times to form a polymer
• Pi-bond (π)


  The reactive part of a double bond formed from the sideways overlap of p-orbitals
• Polymer


  A long chain molecule built up from monomer units
• Sigma-bond (σ)


  A covalent bond formed by the end to end overlap of orbitals
• Stereo/Geometric Isomers


  Molecules with the same structural formula but with a different arrangement of atoms in space (e.g. E/Z and cis-trans)
• Biofuel


  A fuel derived from recently living material
• Dehydration


  An elimination reaction where water is removed from a saturated molecule to form an unsaturated molecule
• Distillation


  The separation of the components in a liquid mixture by evaporation and condensing due to differences in boiling points
• Elimination Reaction


  A reaction where a molecule is removed from a saturated molecule to make an unsaturated molecule (1 becomes 2 etc.)
• Primary alcohol


  An alcohol where the carbon atom containing the OH is directly bonded to 1 other carbon atom
• Reflux


  The continual boiling and condensing of a reaction mixture without loss of volatile product