Basic concepts of organic chemistry

• Organic Chemistry


  The study of carbon compounds
• Carbon atoms


  • Form strong covalent bonds
  • Can be arranged in straight chains, branched chains, or rings
  • Other atoms can be placed on the carbon backbone, and groups can be placed in different positions along the backbone

  
• C to C bonds


  Can be single (C-C), double (C=C), or triple (C≡C)
• Key organic chemistry terms

  • General formula
  • Molecular formula
  • Empirical formula
  • Displayed formula
  • Skeletal formula
  • Structural formula

  
• General formula


  The simplest algebraic formula of a member of a homologous series, e.g. for an alkane the general formula is CnH2n+2
• Molecular formula


  The exact number of atoms of each element present in the molecule - the minimum detail needed to understand the composition of the molecule
• Empirical formula


  The simplest whole number ratio of atoms of elements present in the molecule/substance
• 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

  
• Structural formula


  The minimal detail that shows the arrangement of atoms in a molecule, with branches shown using brackets
• Homologous series


  • A series of organic compounds having the same functional group but with each successive member differing by CH2
  • All have the same general formula
  • Contains the same functional group
  • Have similar chemical properties
  • Show a gradual change in physical properties as molar mass increases
  • Can usually be prepared by a similar method
• Functional group


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


  A compound containing hydrogen and carbon only
• Saturated


  Single carbon-carbon bonds only
• Unsaturated


  The presence of multiple carbon-carbon bonds, including double bonds, triple bonds, and aromatic rings

  
• Alicyclic


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

  
• Alkyl group


  Species with the formula CnH2n+1, e.g. methyl (CH3), ethyl (C2H5), pentyl (C5H11)

  
• Aromatic


  A compound containing a benzene ring

  
• Aliphatic


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

  
• STEM (number of carbons in the longest chain bearing the functional group)

  • 1-Meth-
  • 2-Eth-
  • 3-Prop-
  • 4-But-
  • 5-Pent-
  • 6-Hex-
  • 7-Sept-
  • 8-Oct-
  • 9-Non-
  • 10-Dec-

  
• PREFIX


  Shows position and identity of any side chains
• SUFFIX


  Shows the functional group which is present, but if the functional group is a halogen, it is named like the other side chains

  
• Cyclo-


  Means a cyclic compound
• Alkenes


  • Belong to the same class of organic compound due to the presence of the carbon-carbon double bond in each of the molecules
  • The carbon-carbon double bond in alkenes is what gives them their characteristic reactions
  • The functional group

  
• Eight homologous series studied at AS

  • Alkanes
  • Alkenes
  • Alcohols
  • Carboxylic acids
  • Aldehydes
  • Ketones
  • Halogenoalkanes
  • Esters

  
• Alkanes


  Don't have a functional group, made up of carbon-carbon single bonds and hydrogen (has the general formula CnH2n+2)

  
• Alkenes


  The functional group is the double carbon carbon bond

  
• Alcohols


  The functional group is the -OH (hydroxyl) group bound to a saturated carbon atom (the general formula for an alcohol is CnH2n+1 OH)

  
• Carboxylic acids


  The functional group is the (carboxyl) group (the general formula for a carboxylic acid is CnH2n+1 COOH)

  
• Aldehydes


  The functional group is

  
• Ketones


  The functional group is part of the carbon chain, rather than at the end like in aldehydes

  
• Halogenoalkanes


  The functional group is a halogen replacing one of the hydrogens
• Esters


  Their functional group is
• Naming organic compounds (Nomenclature)


  The area that is to the right of the functional group makes up the first part of the name, and the area to the left of the functional group makes up the second part of the name
• IUPAC systematic naming system (alkanes)

  1. Identify the longest continuous carbon chain

  2. Count from either direction to find the lowest carbon number the any branch(es) could be on

  
• Naming alkenes


  1. Count the carbons so that the functional group is on the lowest carbons

  2. Functional group position takes priority over methyl position

  3. Di in front of the name ending if two functional groups

  
• Naming alcohols


  1. The prefix is only used if the compound has more than 1 functional group

  2. The more important group is named in the suffix, the less important in the prefix
• Suffix names


  • -oic acid (Carboxylic acid)
  • -oate (Ester)
  • -amide (Amide)
  • -nitrile (Nitrile)
  • -al (Aldehyde)
  • -one (Ketone)
  • -ol (Alcohol)
  • -amine (Amine)
  • -ene (Alkene)
  • -yne (Alkyne)
  • -ane (Alkane)
• Prefix names


  • Carboxyl
  • Alkoxycarbonyl
  • Amide
  • Cyano
  • Oxo (-O)
  • Formyl (-CH-O)
  • Hydroxy
  • Amino
  • Alkenyl
  • Alkynyl
  • Alkyl
  • Alkoxy
  • Halo

  
• Naming halogenoalkanes


  1. Always use the prefix for the group name

  2. If there is more than one halogen, the one earlier in the alphabet takes priority