4.1.1 basic concepts and hydrocarbons

• What is a general formula in organic chemistry?

  An algebraic formula for a homologous series, e.g., CnH2n
• What is a displayed formula?


  • Shows all the covalent bonds present in a molecule
  • Represents the arrangement of atoms and bonds
• What is the shape around the carbon atom in saturated hydrocarbons?

  The shape is tetrahedral with a bond angle of 109.5°
• What defines an aliphatic compound?

  A compound containing carbon and hydrogen joined in straight chains, branched chains, or non-aromatic rings
• What defines an alicyclic compound?

  An aliphatic compound arranged in non-aromatic rings with or without side chains
• What defines an aromatic compound?

  A compound containing a benzene ring
• What is a homologous series?

  Families of organic compounds with the same functional group and general formula
• How do members of a homologous series differ?

  Each member differs by CH2 from the last
• What is a functional group?

  An atom or group of atoms that causes different molecules to have similar chemical properties
• What are the suffixes and prefixes for different functional groups?

  • Alkanes: -ane
  • Alkenes: -ene
  • Alcohols: -ol
  • Haloalkanes: chloro-, bromo-, iodo-
  • Aldehydes: -al
  • Ketones: -one
  • Carboxylic acids: -oic acid
  • Esters: -yl –oate
• What is the code for the number of carbons in organic compounds?

  meth (1), eth (2), prop (3), but (4), pent (5), hex (6), hept (7), oct (8), non (9), dec (10)
• What are the general rules for naming carbon chains?

  • Count the longest carbon chain and name it
  • Identify and count branched chains
  • Add appropriate prefixes for each branch
• How is the position of a functional group indicated in a carbon chain?

  By a number, counting from the end that gives the functional group the lowest number
• How are multiple functional groups or side chains listed in a compound's name?

  In alphabetical order, ignoring di, tri, etc.
• What happens to the suffix when it starts with a vowel?

  Remove the –e from the stem alkane name
• What happens when the suffix starts with a consonant?

  Do not remove the –e from the stem alkane name
• How do functional groups affect numbering in a compound?

  They take precedence over branched chains in giving the lowest number
• What is the naming convention for haloalkanes?

  Class the halogen as a substituent and use the suffix -fluoro, -chloro, -bromo, or -iodo
• How are alcohols named?

  They have the ending -ol, with the position number for the OH group added if necessary
• What is the naming convention for aldehydes?

  An aldehyde’s name ends in –al and always has the C=O bond on the first carbon
• How are ketones named?

  Ketones end in -one and require a number for the position of the double bond if there are 5 or more carbons
• What is the naming convention for carboxylic acids?

  They end in -oic acid, with no number necessary for the acid group
• What is the naming convention for esters?

  Esters have two parts to their names: one ending in -yl from the alcohol and the other ending in -anoate from the carboxylic acid
• What are structural isomers?

  • Compounds with the same molecular formula but different structures
  • Can arise from chain isomerism, position isomerism, or functional group isomerism
• What is chain isomerism?

  Compounds with the same molecular formula but different structures of the carbon skeleton
• What is position isomerism?

  Compounds with the same molecular formula but different structures due to different positions of the same functional group
• What is functional group isomerism?

  Compounds with the same molecular formula but with atoms arranged to give different functional groups
• What is homolytic fission?

  A process where a bond breaks and each atom gets one electron from the covalent bond
• What do free radicals represent?

  Reactive species that possess an unpaired electron
• What is heterolytic fission?

  A process where one atom gets both electrons from a covalent bond
• What do curly arrows represent in mechanisms?


  The movement of an electron pair, showing the breaking or formation of a covalent bond
• What is the significance of the carbon's positive charge in reactions?

  It arises from the electronegativity difference between carbon and the halogen
• What is the purpose of drawing mechanisms in organic chemistry?

  To show in detail how a reaction proceeds
• What is the role of a two-headed arrow in mechanisms?

  It shows the movement of a pair of electrons
• What is the primary method by which most organic reactions occur?

  Via heterolytic fission, producing ions
• hydrocarbon - compound with hydrogen and carbon atoms only
• saturated - compounds containing single carbon to carbon covalent bonds
• unsaturated - compounds containing double carbon to carbon covalent bonds
• functional group - atom or group of atoms which when present in different molecules causes them to have similar chemical properties
• skeletal formula - no carbons and their corresponding hydrogens are drawn