Review of Organic Chemistry: Structures and Reactions of Organic Molecules
Reading Assignment: Read the information boxes on orgainc molecules at the Okanagan University College web site listed elow. Read the slide presentations on Professor James Hardy's web site, University of Akron, and click on the examples for (1) alkanes, (2) unsaturated hydrocarbons, (3) alcohols, phenols and ethers, (4) aldehydes and ketones, (5) carboxylic acids, and (6) amines and esters. Read Manahan, Chapter 23--Toxicological Chemistry. Download the chime plug-in and study the different molecules on the molecular models web site linked below.
Homework: HW-7 Due Thursday, March 8.
NOTE: The 3-D structures included in this lecture require a plug-in for your browser called Chime. It is available free from the MDL Web site MDLChime Plug-in. Although Chime is configured to work with IE and Netscape, we recommend using Netscape 4.80 with Chime 2.60 for optimum results.
A very large percentage of the substances that cause detrimental effects on the environment are synthetic organic molecules. These substances have been shown to accumulate in the food chain and to degrade very slowly in the environment. It is necessa ry to have a general understanding of the properties of these molecules before we can understand their behavior in the environment, and before actions can be take to remove them from areas that have been contaminated with organic chemicals.
Physical Properties (General Rules for Organic Molecules):
Chemical Properties (General Rules for Organic Molecules):
Lewis Representations for Atoms
Combining Atoms to Form Molecules:
Lewis Rules for Molecules:
The Lewis Rules help us understand the bonding in organic molecules, and help to keep track of the electrons.
The Lewis Rules do not tell us anything about the shape or structure of molecules.
There are three kinds of carbon atoms:
The structure of organic molecules is very important, because many of the physiological properties of these substances are based on the shape and size of the molecule.
Ways to represent ethane (C2H6):
Ways to represent ethene, or ethylene (C2H4):
Ways to represent ethyne, or acetylene (C2H2):
Inserting an oxygen atom between the carbon and hydrogen atoms leads to a new class of organic molecules called alcohols. The two-carbon alcohol is called ethyl alcohol or ethanol.
An oxygen atom that has a double bond with carbon will be in one of three classes of organic compounds. An aldehyde results from a carbon atom forming a double bond to oxygen, and a single bond to carbon and a single bond to hydrogen. Acetaldehyde is an example:
A ketone results from a carbon atom forming a double bond to oxygen, and both single bonds are to other carbon atoms. Acetone is an example:
A carboxylic acid results from a carbon atom forming a double bond to oxygen, and one single bond is to a carbon atom and the remaining single bond is to a hydroxyl group (-OH). These compounds are called carboxylic acids. Acetic acid is an example:
An important class of organic molecules in photochemical smog formation is the peroxyacids. These result when a carbon atom forms a double bond to oxygen, one single bond is to a carbon atom and the remaining single bond is to a peroxide group (-OOH). An example is peracetic acid:
Environmental Chemistry -- ENV 440