DF 2

• Alkenes can undergo addition reactions due to their unsaturated nature
• Alkanes

  • methane, ethane, propane
• Alkanes are saturated hydrocarbons with the general formula CnH2n+2
• Alkenes are unsaturated hydrocarbons with the general formula CnH2n and have one double covalent bond
• Cycloalkanes have a general formula of CnH2n without the +2 at the end, similar to alkenes with one double bond
• Alkanes contain hydrogen and carbon only and each carbon is bonded four times with the maximum number of hydrogens possible
• Developing fuels topic for organic nomenclature and structural isomerism

  Overview for vision purposes
• Double bonds in alkenes have high electron density making them reactive
• Alkenes

  • ethene (CH2CH2), but-1,3-diene
• Cycloalkenes have two fewer hydrogens compared to their straight-chain counterparts
• Cycloalkene


  • Cyclopentene (CnH2n-2)
• Aromatic compounds contain a benzene ring with delocalized electrons
• Arenes are a group of organic molecules with a benzene ring structure
• Aliphatic compounds are straight, branched, or non-aromatic chains
• Benzene has the formula C6H6 and consists of a ring of carbons with three double bonds that are delocalized
• IUPAC is the global language of chemistry
• E double bonds are not attached to any particular carbon though they are delocalized in reality, allowing them to move around the whole benzene structure
• Naming molecules according to IUPAC

  1. Find the length of the stem by counting the longest continuous chain of carbons

  2. Identify the functional group

  3. Number the chain so the functional group has the lowest possible number

  4. Name the molecule based on the carbon number the functional group is attached to

  5. Include any side chains and less important functional groups as prefixes in alphabetical order

  6. Use numerical prefixes like di-, tri-, tetra- for multiple identical functional groups
• IUPAC stands for the International Union of Pure and Applied Chemistry
• Homologous series

  • Alkanes end in -ane (e.g., butane), Alkenes end in -ene (e.g., propene), Alcohols end in -ol (e.g., ethanol), Alkynes end in -yne, Aromatics end in -benzene, Haloalkanes use prefixes like fluoro-, chloro-, bromo-, iodo (e.g., bromoethane)
• Alkenes have atoms around a double bond arranged in an equilateral triangle with bond angles of 120 degrees
• Alkanes have a fixed angle of 109.5 degrees due to the repulsion of bonds, giving them a specific shape
• Sigma bond

  Contains two orbitals that overlap and align horizontally, forming a single covalent bond with a strong electrostatic attraction between nuclei and shared electrons
• Alkanes always form a tetrahedral shape around the carbon atom with bond angles of 109.5 degrees
• PI bond

  Results from the parallel overlap of two P orbitals, forming a weaker bond than Sigma bonds with electron density spread out over a larger area
• Unique formulas

  • Alkanes: CnH2n+2
  • Alkenes: CnH2n
  • Alcohols: CnH2n+1OH
• Molecular formula

  The actual number of atoms in a molecule or an element
• Shortened structural formula

  Arrangement of atoms in a molecule without showing any bonds
• Skeletal formula

  Shows the bonds of the carbon skeleton only, functional groups are shown
• Structural formula

  Shows the arrangement of atoms showing all the bonds and atoms in the molecule
• Homologous series have the same functional group and general formula, allowing for the calculation of molecular formulas
• Successive members of the same homologous series increase by CH2 each time
• Pi bond

  • Weaker electric static attraction, lower bond enthalpy, breaking a pi bond is easier than breaking a sigma bond
• Structural isomers may have similar chemical properties but different physical properties such as boiling points
• Chain isomerism is one type of structural isomerism where compounds have the same elements but different arrangement on the carbon skeleton
• Positional isomers


  • Pen-1-ol and Pen-2-ol
• Functional group isomers have the same molecular formula but a different functional group
• Positional isomers have the same molecular formula but a different position of the functional group on the carbon skeleton
• Isomers have different physical and chemical properties even if they have the same molecular formula
• Functional group isomers

  • Pent-1-ene and Cyclopentene