Introduction to organic chem

• Molecular formula


  The number of atoms of each element

  eg: ethane -> C2H6
• Empirical formula


  The molecular formula in the smallest whole number ratio

  eg: ethane (C2H6) -> CH3
• Structural formula


  The formula by each carbon atom

  eg: ethane (C2H6) -> CH3CH3
• Display formula


  shows arrangement of atoms

  eg: ethane ->

  
• General formula


  An algebraic formula that can describe any member of a family of compounds eg: alkenes -> CnH2n
• Skeletal formula


  Shows bonds of carbon skeleton only (inc any functional groups)

  eg: hex-1-ene ->

  
• Homologous series


  group of molecules with same functional group and general formula
• Alkanes general formula

  CnH2n+2
• Halogenolkanes


  similar structure to alkanes but at least one H is replaced with halogen
• Cycloalkanes


  a ring of carbon atoms with two hydrogens attached to each carbon

  
• General formula of alkenes


  CnH2n
• Alcohols


  contain hydroxyl (-OH) group

  
• Aldehydes


  one of end carbons a C=O double bond

  have suffix -al

  eg: propanal

  
• Ketones


  contains oxygen double bond but not at end carbon

  suffix of -one

  eg: propanone

  
• Carboxylic acids


  contain carboxyl (-COOH) functional group

  
• reaction mechanism diagrams use curly arrows to show how pairs of electrons are transferred
• Structural isomers have the same molecular formula but different structural formula (arrangement of atoms)
• Position isomers have the same skeleton with the functional groups/other atoms attached to a different carbon
• Chain isomers have the same functional group but different arrangements of the carbon skeleton

  some are straight chains and others are branched in different ways
• Functional group isomers have the same atoms arranged into different functional groups

  eg: alkene could become a cycloalkane
• Stereoisomers have the same structural formula, but their atoms are arranged differently in space
• E/Z isomerism occurs in molecules with carbon double bonds
• Carbon atoms in a C=C bond along with the atoms bonded to the carbons are trigonal planar (120o)
• C=C bonds cannot rotate
• E-isomers have matching groups diagonal from one another

  
• Z-isomers have matching groups both above or below the double bond

  
• Cahn-Ingold-Prelog priority rules

  the lowest priority is given to the atom/s with the lowest atomic number and highest priority to the atom/s with the highest atomic number.
• If two atoms have the same atomic number, then the next lower priority element will be used as a tiebreaker