Organic Chemistry test 2

• Molecular representations


  Different methods of representing organic molecules
• Molecular representations


  • Molecular formula
  • Empirical formula
  • Lewis Structure
  • Condensed Structure
  • Line bond structure
  • Wedge representation
  • Sawhorse representation
  • Newman projection
• Empirical formula


  Simplest whole number ratio of atoms in a compound
• Empirical formula


  • C2H5
• Molecular formula


  Actual number of atoms of each element in a compound
• Molecular formula


  • C4H10
• Lewis Structure


  Shows all bond lines and non-bonding lone electron pairs
• Condensed Structure


  Omits bond lines (single bonds) and lone pairs
• Condensed Structures


  • Use brackets for repeating groups
  • Heteroatoms = those atoms that are not C or H
• Line-bond, skeletal structure


  2 bonds = 2 hydrogens inferred

  1 bond = 3 hydrogens inferred
• Drawing line-bond structures


  Omit all hydrogen atoms except for functional group H atoms

  2. All other atoms must always be shown

  3. Show all C-C bonds as solid lines (C=C bonds as 2 solid lines, etc.)

  4. Lone pairs do not always have to be shown

  5. Formal charges must always be shown

  6. Three-dimensional geometry does not always have to be shown

  7. End of a line is a terminal carbon

  8. Interior carbon atoms are bends in the line
• Drawing line-bond structures - Example 1


  • Draw a line-bond structure for following Lewis structure
• Drawing line-bond structures - Example 3


  • Draw a Lewis structure for following line-bond structure
• Alexander/wedge representation


  Sawhorse representation (oblique angle view of C-C bond)

  Newman projection (front C presented as a dot, back C as a circle)
• Functional group


  An atom or group of atoms within a molecule that shows a characteristic set of predictable physical and chemical properties

  The units by which we divide organic compounds into classes

  The sites of characteristic chemical reactions

  The basis for naming organic compounds
• Functional groups in Organic Chemistry

  • Highest priority

  Lower priority

  Higher priority

  Lowest priority
• Organic Chemistry


  Chemistry of carbon compounds, branch of Chemistry that deals with the study of the structure, properties and changes of carbon compounds
• Over 90% of compounds are organic
• Knowledge in organic chemistry is important to understand

  • Biochemistry
  • Pharmacology
  • Therapeutics
  • Clinical chemistry
• For Pharmacy students, knowledge in organic chemistry is important for


  • Pharmaceutical chemistry
  • Pharmacognosy
• Applications of Organic Chemistry

  • Synthesis and classification of medicines
  • Understanding biomolecules and their biochemical functions
  • Prediction of therapeutic uses, adverse effects, and interactions of medicines
  • Structure-activity relationships of medicines
• Why devote a whole branch of chemistry to Carbon?

  • Forms strong bonds with other carbon atoms and a wide variety of other elements
  • Chains and rings of carbon atoms form a variety of molecules
  • Diversity of carbon compounds provides the basis for life
• Atomic structure of Carbon


  • Protons, neutrons, and electrons
  • Isotopes
• Modes of carbon bonding

  • Carbon can form single, double and triple covalent bonds with another carbon
  • Unique property that differentiates carbon from the other elements
  • Allows the formation of so many different organic compounds
  • Formation of single, double and triple bonds with elements other than carbon, usually oxygen (O), nitrogen (N), sulfur (S) and the halogens (X)
• Configuration of carbon


  • Electron configuration of Carbon (C): 1s2 2s2 2p2 (Ground state), 1s2 2s1 2p3 (Excited state)
  • Covalent bonds: sharing of electrons between atoms
  • Carbon can accept 4 electrons from other atoms
  • Carbon is tetravalent (Valency = 4)
• Classification of Organic compounds by functional group

  • Hydrocarbons
  • Halo-alkanes (Alkyl-halides)
  • Alcohols
  • Ethers
  • Aldehydes
  • Ketones
  • Carboxylic acids
  • Esters
  • Amines
  • Amides
• Functional group


  An atom or a group of atoms with characteristic chemical and physical properties
• Importance of Functional Groups

  • Determine bonding and shape
  • Determine type and strength of intermolecular forces
  • Determine physical properties
  • Determine nomenclature
  • Determine chemical reactivity
• Properties of Organic Compounds

  • Have covalent bonds
  • Have low melting points
  • Have low boiling points
  • Are flammable
  • Are soluble in non-polar solvents
  • Are not soluble in water
• Properties of Organic Compounds

  • Composed of stable C-C covalent bonds
  • Have defined molecular structures
  • Have defined three-dimensional shapes
• Characteristics to identify as most typical of compounds that are

  • inorganic
  • organic
• Hydroco


  • a
  • bens
• Hydro cardions


  • Bengame
  • Alkylbenzenes
• Alkanes


  • Single bonds
  • C and H
  • C and C
  • CnH2n+2
  • Aliphobic
  • Algelica
  • Aliegele
  • Straight chain
  • Cycloalkanes
  • Cycloolkenes
  • Branched chain
• Alkanes are fully saturated
• Methane


  CH4, tetrahedral
• Ethane


  CH3CH3, all carbon atoms are sp3 hybridised
• Propane


  CH3CH2CH3, all carbon atoms are sp3 hybridised
• Alkanes


  • Zigzag chain shape
  • CH3- and -CH2- groups
• Branched-chain alkanes


  • Methylpropane
  • Isomers