Unit 2 – Day 1 Organic Chemistry Intro

Organic Chemistry Organic chemistry is the study of compounds found in living things. The most common elements in living things are carbon, hydrogen, nitrogen, and oxygen. These four elements constitute about 95% of your body weight. Organic molecules may also have S, P and the halogens.

Carbon Carbon is the most common element found in organic molecules. The chemistry of carbon allows it to form an infinite number of molecules. Carbon bonds to itself, and can form long chain and ring shapes in molecules. The structure of these molecules determines their function in the body.

Organic Molecules There are tens of millions of organic molecules. They are present everywhere in our lives. Proteins, sugars and fats in our food are organic. Oil, gasoline, synthetic fibres and plastics are all organic.

Organic vs. Inorganic Organic molecules involve carbon bonded in chains with hydrogen and other non-metals. Not all molecules with carbon are organic. Example: Carbon dioxide, calcium carbide – No hydrogen, no chain formed.

The source of organic compounds Living things produce organic compounds. Because of this, we must get organic compounds from living things, or things that were alive at some point. Most of the organic molecules used in industry ultimately come from crude oil.

Crude Oil Crude oil and other fossil fuels were formed millions of years ago, during the carboniferous period. If living things died and decayed without oxygen, under heat and pressure, they were converted to fossil fuels. Plant life became coal, while algae and plankton became oil.

Fractional Distillation Crude oil by itself is not terribly useful because it is a mixture of so many organic molecules. In industry, this oil is separated using a process called fractional distillation.

Fractional Distillation It works by heating the bottom of the column. As you move up the temperature drops. Heavier molecules are still liquids, even at high temperatures, while the lighter molecules become gas and rise in the column. This process separates crude oil into several useful parts.

Cracking Large molecules like tar have uses, but they are much more valuable as smaller molecules (like jet fuel, gasoline or natural gas). Some of these molecules can be “cracked” into smaller molecules using catalysts, or heat and pressure.