Learning Objectives

Organic Chemistry

Organic Chemistry is the study of compounds based on the element carbon. The name organic is derived from the word organisms. The chemical compounds which make up plants and animals use carbon atoms as the basic structural material. What makes organic compounds the basis of all life is the variety of different arrangements of these carbons and the other atoms attached to them.  Carbon is unique in that it forms strong covalent bonds to other carbons thereby creating a vast number of parent carbon skeletons for organic compounds.

The compounds that are based on carbon require a much more specific nomenclature than inorganic compounds.

Functional groups are so named because they are reactive in chemical reactions. Some of the more common functional groups are shown in the following table.

alkanes	CH4
alkenes
alkynes
aromatic compounds
halide compounds	CH3-Br
alcohols
ethers
mercaptans
sulfides
amines
nitro compounds
aldehydes
ketones
carboxylic acids
esters
amides

Many of these functional groups can exist together in the same molecule thus there exists an infinite number of unique compounds, each with different physical and chemical properties.

Polymers

Polymers are ubiquitous in the world in which we live.  The main structural building materials of all living things are natural polymers.  Proteins are the structural polymers found in animals. Cellulose is the structural polymer of plants. Polyisoprenes are obtained from approximately 500 species of plants including milkweed and dandelions.

Synthetic polymers are used from everything from kayaks to the clothing we wear. The word polymer is derived from the Greek "poly" meaning many and "meros" meaning parts.

Polymers are large molecules made up of many repeating sub structures called monomers. The formula weight of a polymer can vary from several thousand amu to over a million amu. A monomer is the structure of the small molecule that is the synthetic precursor of a polymer. The reaction that unites monomer molecules into a polymer molecule is called polymerization.

Copolymers can be made when more than one type of monomer is used for the reaction.

Polymers are frequently called plastics but that is not really correct since not all polymers are plastics. The word plastic is derived from the Greek plastikos (moldable). A plastic is a polymer that at some point in its preparation is moldable into various shapes.

Plastics can be either thermosetting or  thermoplastic. Thermosetting plastics are moldable when first heated, but after they cool, they will no longer soften when heated. Thermoplastic polymers can be repeatedly softened by heating.

Recycling Polymers

Thermosetting polymers cannot be recycled because they just decompose if they are heated. Thermoplastic polymers can be recycled because they can be heated and remolded into new shapes. The major problem with recycling plastics is that they must be sorted by polymer composition. If the polymers were just mixed, called commingled plastic, they would not be able to be shaped into useable objects. The reason for this is the physical properties such as the melting point would be too variable in commingled plastic.

The codes for recycling plastics are given in the following table.

Code	Polymer
1   PETE	polyethylene terphthalate
2   HDPE	high density polyethylene
3   V	polyvinyl chloride
4   LDPE	low density polyethylene
5   PP	polypropylene
6   PS	polystyrene
7   OTHER	all other

Degradable Polymers

Degradation of polymers can be accomplished by microorganisms or by photodegradation. Many polymers are made to degrade more readily by the addition of additives. Thermosetting polymers are an important target for these additives because they cannot be recycled. Photodegradable plastics can have an additive that is sensitive to ultraviolet light. Biodegradable plastics can have starch or cellulose incorporated into the resin at the time of manufacture. Microorganisms would consume the starch or cellulose and the plastic would be broken down into small  pieces. Photodegradation depends on light and oxygen, both of which are excluded in landfills.  Biodegradation depends on moisture and that also is limited in landfills. Newspapers have been found in landfills relatively unchanged after 20 years.

Nutrition

Nutrition is the study of foods and the ways in which the body utilizes them. Humans must have a diet of six basic ingredients.  These ingredients are water, carbohydrates, fats, proteins, vitamins and minerals. Carbohydrates and fats supply most of the energy the body requires and proteins supply the materials needed for the biosynthesis of tissue and organs. Vitamins and minerals are needed to regulate the biochemical reactions in the body.

Most nutritional deficiency diseases are caused by the lack of protein in the diet. Malnutrition is caused by a diet that is lacking in the proper mix of nutrients even though the diet may contain adequate calories. Undernourishment is caused by a lack of adequate quantities of food regardless whether the food has the proper mix of nutrients.

The basal metabolism rate (BMR) is the amount of energy required to maintain the normal functions of the body at rest. This energy is approximately one Calorie per kilogram of body weight per hour depending on age and size.

A 150 pound person (68 kilograms) would require 1632 Calories per day for their BMR (68 kg x 1 Cal/kg x 24 hours/day). This amounts to about 60-75% of the calories you expend on a daily basis. Additional Calories are required for any physical activity. 

The following table shows the Calories per minute burned in various activities for different body weights.

If a 150 pound person eats one slice of pizza, they would have to run for 10 minutes or walk for 30 minutes to work off the calories...bummer! A single chocolate chip cookie requires a 3 minute run or a 10 minute walk. A hamburger requires a 20 minute run or a 60 minute walk.

The average input of Calories per person per day in the United States is 3,626 Calories. The average input for people in developing countries is 2,352 Calories. We, as a nation, are consuming an average of 1,000 Calories per day in excess of what is desirable to maintain a healthy weight. Twenty seven percent of our population is up to 40% over their ideal weights. About 50% of adult women and 25% of adult men try to lose weight by dieting.

Dieting alone is doomed to failure. Your body responds to a severely restricted caloric consumption by conserving energy (it burns fewer calories). If you switched from an 1800 Calorie diet to a 1200 Calorie diet, your BMR will be lowered about 10%. If your diet was reduced further to an 800 Calorie diet, your BMR will be reduced an additional 10%. This compensatory metabolic slow-down will last well after you have finished your diet regime because the body weight lost during dieting is about 50% fat and 50% muscle tissue. The net result of losing muscle mass will be a reduction in your metabolic rate. Once you discontinue to severely restrict your caloric intake, you will more than likely regain the weight that was lost within a relatively short time span.

The only answer for long-lasting weight reduction is to burn more calories than are ingested. A change of lifestyle must be adopted which involves regular exercise in conjunction with a permanent reduction in the number of calories consumed.

It takes two types of exercise to help you lose weight effectively and maintain the weight loss. Aerobic exercise is designed to burn a large number of calories and weight training is designed to build and preserve muscle tissue. Increased muscle mass increases your basic metabolic rate which allows you to burn a greater number of calories at rest. In general, even a combination of aerobic exercise and dieting does little to help you maintain lean body mass during the weight loss period and this regime also has found limited long-term success. The optimal solution for sound weight management is one that combines aerobic conditioning, strength training and dieting.

Problems

1. Name the following compounds...click on each formula for the answer.

2. Draw structures for the following compounds…

pentane

octane

2-methylhexane

2,2-dimethylpropane

3. Define the following terms.

HDPE

monomer and polymer

thermoplastic and thermosetting plastics

biodegradation and photodegradation

4. Discuss the pros and cons of paper versus plastic grocery bags.

6. What is the difference between addition polymerizations and condensation polymerizations?

7. What is the functional group of the following compound?

8. What is the functional group of the following compound?

9. What is the functional group of the following compound?

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Copyright © January 2001 by Richard C. Banks...all rights reserved.