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• Up to this point the matter that we have discussed has been inorganic matter.
• Scientist tend to study either the organic or inorganic matter.
• For example in chemistry, organic chemistry is taught a separate course and organic chemist is a subdiscipline in chemistry.
• Living matter is organic but not all non-living matter is inorganic so that division is a generalization. • The division based on whether the compound or matter contains carbon is a more accurate one.
• The first two points are related since substances with low melting point will exist as a liquid.
• Inflammable and flammable are synonyms.
• The low solubility in water is expected since organic compounds are generally non-polar.
• This is similar to silicon which also is a column four element.
• The field of organic chemistry is filled with nomenclature for classifying compounds.
• The carbon atoms in organic molecules are either in a chain or in a ring.
• Benzene as we will see later has a six-carbon ring.
• These concepts or terms will become more clear as we describe the molecules.
• These are all flammable gases. Butane is the gas the the cylinders that I use for the demonstrations. Propane is the gas that is used in BBQ and portable heaters.
• The alkanes have the formula CnHn+2 
• Demo of ball and stick model to show 3D arrangement of atoms.
• Eclipsed vs. staggered orientation for ethane
• Stable conformation for propane
• Octane rating of a gasoline is an indication of the resistance to premature detonation. The higher the octane number the less likely that premature detonation or knocking will occur. The term octane number was used because isooctane an isomer of octane was used as the reference for an octane number of 100.
• We will define what an isomer is in the next slide.
• Octane ratings for gas is typically 87, 89 or 93.
• Show ball and stick model to explain why there are no isomers.
• To describe the isomer one may write the formula to indicate the manner in which the atoms are arranged in the molecule.
• Put together an isobutane model from methane and propane models.
• This is the structure of isooctane which is an isomer of octane.
• We can build up different molecules by attaching different radicals.
• We will consider replacing the hydrogen atoms with other atoms or radicals.
• So far we have described saturated hydrocarbons.
• Saturated fats are fats that have as many hydrogen as it may have.
• Alkenes are therefore unsaturated hydrocarbons.
• Formula for alkenes is CnH2n.
• Ethylene - 14 million tons produced annually - used to make polyethylene
• Propylene - 7 million tons produced annually - used to make polypropylene
• Note that every carbon has four bonds and every hydrogen has one bond.
• Mdel of ethylene and bonding.
• Acetylene is a gas that is used in welding and is extremely flammable.
• Ethyl alcohol is the alcohol in alcoholic beverages.
• Methyl alcohol is highly toxic, however ethyl alcohol is also toxic. In a large enough dose ethyl alcohol is fatal.
• Ball and stick model of alcohols
• These compounds are considered aliphatic even though they are in a ring because they are similar to the open chain molecule except that they are placed in a ring.
• Use methane or propane model to show how cyclopropane is made.
• Resolving the structure of benzeneis an interesting problem
• Several pieces of information was known about benzene.
• The chemical formula was known.
• The effect of replacing  the hydrogen atoms with different atoms was studied.
• This is a fairly accurate picture of benzene. It is a 2D molecule.
• Difference between conformation isomers and configurational isomers.