Hydrocarbons:

        All hydrocarbons, whether aliphatic or aromatic, are insoluble in water (which would imply that they are nonpolar.)  All are less dense than water as well, and all burn in air.

Alkanes

• Nonpolar

• Contain only C-C single bonds.  All bonds are sigma.  There is free rotation aroud the single bonds.

• In regards to structural isomers, the more highly branched an isomer is, the lower the boiling point.

• Combustion is the only reaction of alkanes.

• Alkanes have sp3 hybridized orbitals, and a tetrahedral geometry.

Alkenes

• Contain C-C double bond; one sigma bond and one pi bond.

• There is no rotation around the double bond.  Lack of rotation contributes to geometric isomers.

• Alkenes have sp2 hybridized orbitals.

• Alkenes are more highly reactive than alkanes because of their pi bonds.

Aromatic Compounds

• Based on the parent molecule benzene.

• Have sp2 hybridized orbitals.

• The benzene ring is perfectly flat with p orbital lobes above and below

• Electrons are delocalized (free to move around in pi orbitals).

• Low chemical reactivity compared with alkenes.  Benzene resists most reactions, but is most likely to undergo substitution reactions.

• Structural isomers of benzene derivatives have different properties.  The closer the substituents are to one another, the higher the boiling point.

Halocarbons

• Compounds that contain carbon-halogen bonds.

• The carbon-halogen bonds are slightly polar.

• Because there are polar bonds, halocarbons can have dipole interactions.

• Can form hydrogen bonds with water, but not with themselves.

   

Alcohols        

• The hydroxyl groups is the functional group of alcohols.  For this reason, alcohols can form hydrogen bonds with themselves (intermolecular hydrogen bonds) as well as with water.

• Alcohols have a higher boiling point than alkanes and halocarbons with similar numbers of atoms. (Because of the intermolecular H bonding.)

• Alcohols can be formed by hydration reactions of alkenes, as well as displacement reactions of halocarbons.

• The hydrocarbond part of the alcohol is nonpolar, so that alcohols with more than four carbons are not very soluble.  Alcohols with small C chains are very soluble.

Ethers

• Have boiling points lower than alcohols, but higher than comparable hydrocarbons and halocarbons.

• More soluble in water than hydrocarbons and halocarbons, but less soluble than alcohols.

• No intermolecular hydrogen bonding, but can H bond with water.

   

Aldehydes        

• The carbonyl group is the functional group of both aldehydes and ketones.

• There is no intermolecular hydrogen bonding but they can form H bonds with water.

• Molecules are polar.

Ketones

• No intermolecular hydrogen bonding, but can H bond with water.

• Molecules are polar.

   

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