What you should remember from last lecture

1. Organic compounds are based on carbon, and form the basis of biology and of many of the materials that you experience every day.

2. Carbon atoms make 4 covalent bonds, to other carbons and to many other elements in the periodic table.

3. Carbons with 4 single bonds are tetrahedral.4. Organic molecules are really 3-dimensional blobs,

not flat (like most drawings).

What you should remember from last lecture

1. Alkanes are simple CnH2n+2 (saturated) hydrocarbons. Cycloalkanes are ring structures with molecular formulae CnH2n.

2. Several isomers (different structures) are possible for most molecular formulae.

3. For practice, can you draw four different hydrocarbons with the molecular formula C6H14? How about four different C5H10 hydrocarbons?

4. Shorthand drawing methods are often used when drawing organic compounds. Remember, carbon makes 4 bonds, whether all 4 are shown or not.

What you should remember from last lecture

1. Alkenes are compounds with C=C double bonds, and alkynes are compounds with C-C triple bonds.

2. Petroleum (oil) is the source of a wide array of solvents, fuels, and compounds from which many products can be made.

3. Petroleum refining begins with distillation, which separates the hydrocarbons according to their boiling points.

4. Cracking is a process that breaks larger molecules into smaller, more valuable ones.

What you should remember from last lecture

1. Alkanes, Alkenes, and Alkynes. 2. Structural Diversit.y 3. Petroleum (oil) is the source of a wide array of

solvents, fuels, and compounds from which many products can be made.

4. Distillation, Cracking, and Reforming are key steps in petroleum refining.

5. Coal is a complex mixture of large molecules that cannot easily be separated into pure compounds, yet represents the major fraction of fossil fuel reserves.

What you should remember from last lecture

• Organic compounds are ensembles of functional groups: commonly occurring groups of atoms with a characteristic reactivity.

• Halogens (fluorine, chlorine, bromine, iodine) are simple functional groups. Chlorinated hydrocarbons are highly useful, but some have harmful properties.

• Polymers are extremely large molecules, assembled from smaller molecules called monomers.

What you should remember from last lecture

• Molecular weight, degree of branching, and amount of crosslinking can affect the properties of a resulting polymer.

• Stereoisomers: Compounds that differ in the 3-D placement of atoms in space. Cis vs. trans C=C bonds can affect the properties of a molecule.

• Polymerization (bond formation between monomers) can be through addition (polyethylene, polystyrene, PVC, others) or condensation (polyamides, polyesters).

What you should remember from last lecture

Many common polymers are condensation polymers. These include polyesters and polyamides.

A plasticizer is often added to a polymer to make it soft and plastic.

Highly crosslinked polymers (like epoxy) tend to be hard, non-flexible, and durable.

Composite materials are composed of a reinforcing material (glass fibers, graphite fibers, others) embedded in a polymer matrix (epoxy, polycarbonate, others).

What you should remember from the last lecture

• Water is a polar molecule, and hydrocarbons are non-polar. Water will interact strongly with other polar molecules, but not with non-polar (greasy) ones.

• Fats and Oils are tri-esters of glycerol and 3 fatty acids. These tri-esters can be converted back to the component fatty acids and glycerol, using NaOH (lye).

• In water, fatty acids form micelles, in which the non-polar tails cluster together and the polar acid groups point out toward the water.

What you should remember from the last lecture

Fats (triglycerides) can be completely (or partially) converted (saponified) into fatty acids and glycerol, or fatty acids and mono- (or di-) glycerides.

Fatty acids are the basis of soaps. These are effective cleaning agents, as they form micelles with non-polar interiors. Fatty acid salts with calcium are insoluble, and form soap scum.

Alkyl benzene sulfonates, alkyl sulfates and non-ionic sufactants (PEG) are cleaning agents that remain soluble when complexed with calcium.

What you should remember from the last lecture

Some organic molecules are Chiral. Chiral objects are not identical to their mirror images. Molecules that contain a carbon that is bound to 4 different things are usually chiral.

Many important biomolecules (molecules of life) are chiral, including most carbohydrates and amino acids, the building blocks of proteins.

Carbohydrates (saccharides) are sugars. Simple sugars have the molecular formula Cn(H2O)n. These compounds usually exist as 5- or 6-membered rings containing one oxygen atom.