It was believed that organic chemicals could only arise in life processes…

That they were a product of life’s vitality in 1828, German Chemist. Friedrich Wohler dispelled that myth when:

(Mineral) Ammonium cyanate, NH4CNO, heated gave (organic) urea (NH2)CO(NH2)

Why is Organic Chemistry Important?

• 90% of compounds are organic

What is an Organic Compound?

• A compound made from carbon atoms
• Has 1+ C atoms
• Has many H atoms
• Many contain O, S, N, and Halogens

Modern Views

• With the exception of petroleum products, geological and elemental carbon is inorganic carbon
• Other carbon-containing molecules are organic by virtue of carbon’s presence
• There are no end to the combinatorial possibilities since C bonds C! (Billions of isomers, different compouds, etc.)

Inorganic Carbon

Elemental Carbon

• Diamond

• Graphite

• Buckminster Fullerene

• Carbon Oxides + Halides

• Carbonates + Carbides

• Simple cyano-compounds like HCN

Organic Compounds

• Contain Carbon

• Have covalent bonds

• Have low melting points (Usually)

• Have low boiling points (Usually)

• Burn in air (oxygen)

• Form large molecules

Hydrocarbons

Compounds of Carbon and Hydrogen only

Physical Properties

• Since hydrocarbons contain only C and H atoms, two elements with very similar electronegativities, bonds between C and H are relatively nonpolar.
• The main intermolecular interaction in hydrocarbons is van der Waals forces: the attraction of the electrons of one molecule for the nuclei of another molecule.
  • The molecules are readily separated due to these weak forces
• The low boiling points and melting points of the smaller molecules are due to the fact that small molecules have fewer electrons and weaker van der Waals forces, compared with large molecules
• These differences in boiling points of the components of petroleum enable the separation of these compounds in a process called fractional distillation
• Hydrocarbons generally have very low solubility in polar solvents
  • This makes them good for solvents for other nonpolar molecules