basic organic concepts and alkenes

• a homologous series is a group of substances that have the same functional group and successive members differ only by a CH2 unit
• aliphatic hydrocarbons are when carbon atoms are joined together in either straight chains or branches chains
• alicyclic hydrocarbons are when carbon atoms are joined together in a ring structure but are no aromatic
• aromatic hydrocarbons are when there is at least one benzene ring in the structure (benzene ring is a circle inside a hexagon)
• nomenclature is the system of naming compounds
• alkanes are aliphatic saturated hydrocarbons
• naming straight chain alkanes:

  • 1 carbon = methane
  • 2 carbons = ethane
  • 3 carbons = propane
  • 4 carbons = butane
  • 5 carbons = pentane
• how to name branched alkanes:

  • stem- the main part of the name comes from the longest carbon chain
  • suffix- the end of the name is the most important part of the functional group
  • prefix- the front of the name identifies the other functional groups and the carbon atom they are attached to
• if you remove a hydrogen from an alkane an alkyl group is formed

  methane into a methyl group
• when naming compounds numbers are used to indicate which carbon the functional group is joined to
• when naming compounds dashes are used to separate numbers from words
• when naming compounds commas are used to separate numbers
• when naming compounds prefixes are written in alphabetical order using the smallest sum of numbers as possible
• di is used to show that there are two of the same functional group
• tri is used to show that there are three of the same functional group
• tetra is used to show that there are four of the same functional group
• the functional group of an alcohol is OH, the prefix is hydroxy and the suffix is ol
• the functional group of an aldehyde is CHO where the C is double bonded to an O and single bonded to a H, the suffix is al
• the functional group of an alkane is C-C and the suffix is ane
• the functional group of an alkene is C double bond C and the suffix is ene
• the functional group of a carboxylic acid is COOH where the C is double bonded to an O, the suffix is oic acid
• the functional group of a haloalkane is F/Cl/Br/I and the prefix is fluoro/chloro/bromo/iodo
• the functional group of a ketone is C-CO-C, the middle carbon is double bonded to an oxygen and the suffix is one
• saturated compounds only have single bonds
• displayed formula shows the relative positions of all the atoms in a molecule and the bonds between them
• structural formula gives the minimum detail for the arrangement of atoms in a molecule
• general formula is the simplest algebraic formula for a homologous series
• skeletal formula is a simplified structural formula drawn by removing hydrogen atoms from alkyl chains
• unsaturated hydrocarbons are organic compounds that contain only carbon and hydrogen and have at least one double carbon bond
• when drawing skeletal formula add in functional groups at the end of carbon lines
• cyclic compounds are commonly shown in skeletal formula, cyclohexane is shown as a hexagon
• aromatic hydrocarbons always have a 6 carbon ring with a molecular formula of C6H6, the structure is very stable because the electrons are shared across all the carbon atoms this part of the molecule is rarely involved in chemical reactions
• structural isomers are compounds with the same molecular formula but different structural formulae
• 3 ways structural isomers can occur:

  • the alkyl groups are in different places
  • the functional group can be bonded to different parts of the chain
  • the functional group could be different due to its place in the chain
• stereoisomers are organic compounds with the sane molecular formula and structural formula but having different arrangements of atoms in space
• E/Z isomerism us a type of stereoisomerism caused by the restricted rotation around the double bond, there are two different groups are attached to both carbon atoms of the carbon double bonds
• how to identify E/Z isomers:

  • locate carbon double bond and redraw molecule so each carbon has two groups one up and one down
  • focus on each carbon atom individually and assign priority to one substituent group based on relative atomic mass, the higher the relative atomic mass the higher the priority
  • us the highest priority groups are on the same side the isomer is Z if they are on different sides the isomer is E
• cis-trans isomerism is a special type of E/Z isomerism where two substituents on each carbon atom are the same, E isomer is also a trans isomer and the Z isomer is also a cis isomer
• homolytic fission occurs when a covalent bond breaks and each electron goes to a different bonded atom, the generates two highly reactive radicals
• reaction mechanisms are models that show the movement of electron pairs during a reaction