Organic Compounds

• Hydrocarbons


  Compounds only comprised of Carbon and Hydrogen
• Alkanes


  • Hydrocarbons that only contain single covalent bonds
  • Molecules are "saturated compounds"
  • Each member differs by one "-CH2" unit from the previous member
  • Have similar structural pattern, physical properties, chemical properties and formula
  • Name comes from "stem" (number of carbon atoms) and ends with "ane"
• Key Properties of Alkanes


  • Have weak intermolecular forces between molecules, resulting in low melting and boiling points
  • Have strong intramolecular forces (single covalent bonds), so large amounts of energy are released when these bonds are broken (exothermic combustion reactions)
  • Melting and boiling points gradually increase as the carbon chain gets longer and the molecules get bigger
• Structural Isomers


  Different arrangements of atoms in a molecule with the same molecular formula
• Naming structural isomers


  1. Identify the longest carbon chain

  2. Identify all alkyl side chains

  3. Preference the order of side chains so they appear as close to the start of the carbon chain as possible
• Alkenes


  • Homologous series of hydrocarbons with at least one carbon-carbon double bond
  • Described as unsaturated hydrocarbons, generally more reactive than alkanes
  • Names end in "ene" and have the general formula CnH2n
• Structural Isomers of Alkenes


  Isomers which result when there are branches off the main carbon chain or the carbon-carbon double bond moves to a different position
• Geometric (cis/trans) Isomers of Alkenes


  • Exist when there are two different groups attached to each carbon atom involved in the double bond
  • In cis isomers, the same group on each carbon is located on the same side of the double bond
  • In trans isomers, the same group on each carbon is located on the opposite side of the double bond
• Benzene (C6H6)


  An aromatic hydrocarbon compound
• Combustion Reactions (Complete Combustion)


  1. When an element or compound reacts with oxygen (and usually a heat source) to produce an oxide and more heat

  2. Hydrocarbons undergo combustion with oxygen to produce carbon dioxide and water
• Incomplete Combustion Reactions


  Occur when there is an insufficient supply of oxygen and often results in the production of Carbon Monoxide and Soot (pure carbon)
• Substitution Reactions


  1. When a C-H bond is broken and replaced by a Carbon-Halogen bond

  2. Only Alkanes and Benzene undergo substitution reactions

  3. Require a catalyst; Alkanes use UV light and Benzene uses an Aluminium salt
• Substitution Reactions cont.


  If the reaction occurs in the presence of excess reactant and are allowed time to go to completion then further substitution will take place
• Substitution Reactions cont.


  • When Benzene undergoes substitution reactions one of its C-H bonds can be replaced by a halogen or methyl group
• Addition Reactions


  1. Alkenes are more reactive than alkanes and the double C-C bond will break allowing for the formation of two more single bonds

  2. These reactions result in the Alkene (unsaturated compound) becoming saturated

  3. The reactions result in two reactant molecules becoming one final product with no other byproducts
• Addition Reactions cont.


  • Alkenes and Hydrogen
  • Alkenes and Halogens
  • Alkenes and Hydrogen Halides
  • Alkenes with Water