Organic Chemistry Branch of chemistry dealing with carbon molecules.
Hydrocarbons Compounds containing only carbon & hydrogen
Why can carbon form so many compounds? It can form up to 4 covalent bonds with other carbon atoms.
What is the maximum # of bonds between any 2 C atoms? A triple bond (3 pairs or 6 electrons)
Properties of hydrocarbon molecules Molecular Low melting points Low boiling points Low H f Low H v High evaporation rate High vapor pressure May be gases, liquids, or solids Decompose on heating Poor conductors of heat & electricity Nonpolar (vdw forces) Dissolve in nonpolar solvents React slowly Solids may be soft or brittle
Bonding capacity of H? 1
Bonding capacity of O? 2
Bonding capacity of the halogens (F, Cl, Br, I)? 1
Bonding capacity of S? 2
Bonding capacity of N & P? 3
Bonding capacity of C? 4
The 4 single bonds of a carbon atom are directed to … the corners of a regular tetrahedron.
Saturated hydrocarbon Hydrocarbon containing only single carbon-carbon bonds
Unsaturated hydrocarbon Hydrocarbon containing at least 1 double or triple carbon-carbon bond
Chemical or Molecular Formulas Tell the kind & number of atoms in a molecule.
Structural Formulas Tell the kind & number of atoms in a molecule. Also attempt to show approximate shapes & bonding patterns of molecules.
Homologous Series A group of related compounds in which each member differs from the one before it by the same additional unit. Properties vary in a predictable way.
Alkanes Homologous series of saturated hydrocarbons. with the general formula C n H 2n+2. Ratio of C to H is n:2n+2
Alkanes Release energy when burned: fuels.
Naming Alkanes Prefix: depends on # of carbon atoms in longest continuous chain. Suffix: ane
Properties of Alkanes Nonpolar. Boiling point as # of carbon atoms . (van der Waals forces increase with size). Insoluble in water. (Like dissolves like.)
Nonpolar The electron cloud of the molecule is fairly evenly distributed. Either: –Molecule has atoms with similar electronegativities –Molecule has high symmetry
Isomers Molecules with the same chemical formula but different structural formulas. Different chemical & physical properties. Different names. Same formula mass & percentage composition.
Isomers # of possible isomers as # of C atoms
Alkenes Homologous series of unsaturated hydrocarbons containing 1 double carbon- carbon bond.
General formula of alkenes C n H 2n
Naming Alkenes Prefix: depends on # of carbon atoms in longest continuous chain. Suffix: ene # in front may give location of double bond.
Properties of Alkenes Slightly more reactive than the alkanes. Double bond is site of reactivity.
Alkynes Homologous series of unsaturated hydrocarbons containing 1 carbon-carbon triple bond.
General formula of alkynes C n H 2n-2
Naming alkynes Prefix: depends on # of carbon atoms in longest continuous chain. Suffix: yne # in front gives location of triple bond.