By Jacqueline Compton Andrew McDonnell Matt Tonkins

What is Organic Chemistry? Organic chemistry deals with carbon compounds. These carbon compounds are the building blocks for all living things on Earth. They play a large roll in the world we live in.

In dealing with organic compounds, it will be useful to know their prefixes and the number of carbon atoms that they represent. Prefix Number of Carbons Meth 1 Eth 2 Prop 3 But 4 Pent 5

Hydrocarbons Hydrocarbons are compounds that contain only carbon and hydrogen. They come in four different forms: Alkanes Alkenes Alkynes Hydrocarbon rings.

Alkanes Alkanes are hydrocarbons that contain only single bonds. They are known as saturated hydrocarbons and are commonly used as fuels. Alkane Formula Methane CH4 Ethane C2H6 Propane C3H8 Butane C4H10 Pentane C5H12

Alkanes Methane(above) and butane(below) are both alkanes, hydrocarbons that contain only single bonds. Propane, C3H8, is commonly used as a cooking fuel.

Alkenes Alkenes are hydrocarbons that contain double bonds. They are examples of unsaturated hydrocarbons. General Formula: CnH2n Alkene Formula Ethylene C2H4 Propene C3H6 Butene C4H8 Pentene C5H10 Ethylene

Isomers of Alkenes Because of the more complicated structure of the alkenes, there are isomers that have to be dealt with. In alkenes with more than three carbon atoms, the location of the double bond is the determining factor in naming the compound. How do you name this thing anyway?

Naming Isomers of Alkenes If the double bond occurs between the first and the second carbon in an alkene such as butene, it is called 1-butene. If the double bond occurs between the second and the third carbon, it is called 2-butene. This is 2-butene because the double bond occurs between the second and third carbon.

Hydrocarbon Rings Many hydrocarbons form rings instead of chains. These rings are also unsaturated hydrocarbons. One of the most important classes of these compounds is the aromatic hydrocarbons which include compounds such as benzene and napthalene. Mothballs contain napthalene The benzene molecule

Hydrocarbon Rings and Resonance Click screen for sound. The carbon-carbon bonds in compounds like benzene demonstrate a unique property called resonance. Resonance is the rapid change of single bonds to double bonds and then back again many times in succession. It is this resonance that makes these compounds so resilient and quickly alters their bond lengths. This is an animation of a benzene molecule demonstrating resonance. Click picture for animation

Hydrocarbon Derivatives The majority of organic molecules contain elements in addition to carbon and hydrogen. Even so, these substances can be viewed as hydrocarbon derivatives because in the place of hydrogen atoms there are additional atoms or groups of atoms called functional groups. Notice in the diagram below how an additional atom or group of atoms replaces a hydrogen

Alcohols Alcohols are organic compounds in which a hydrogen has been replaced with a hydroxide group (OH). The hydroxyl group makes alcohols polar, which means that they are more soluble in water than most other organic compounds. Methanol Alcohol Formula Methanol CH3OH Ethanol C2H5OH Propanol C3H7OH

Alcohols Alcohols are present in drinks where they function as depressants. They are also used as disinfectants with household and medical uses.

Organic Acids Organic acids are organic compounds in which a carboxyl group (COOH) replaces a hydrogen. Organic Acid Formula Formic Acid HCOOH Acetic Acid CH3COOH Butyric Acid C3H7COOH This is the general structure of An organic acid. The “R” in the diagram represents the rest of the hydrocarbon chain.

Organic Acids Organic acids such as acetic acid are found in products such as vinegar, aspirin, and plastics. They are also present in the cells of bacteria.

Halides Halides are organic compounds in which one or more hydrogen atoms have been replaced with a halide (F, Cl, Br, I). Halides like dichloromethane are present in paint remover and serve as aerosol propellants and foaming agents. Halide Formula Chloromethane CH3Cl Chloroethane C2H5Cl Chloropropane C3H7Cl

Amines Amines are organic compounds in which a hydrogen atom has been replaced by an amino group (NH2). Amines like serotonin (left) are responsible for regulating many functions of the brain.

Aldehydes An aldehyde contains a carbonyl group (C=O) connected to at least one hydrogen atom. Aldehydes are commonly used in the chemical industry and serve as disinfectants, insecticides, fungicides, deodorants, and preservatives.

Ketones Ketones are similar to aldehydes because they also contain a carbonyl group (C=O), but in a ketone the carbon in the carbonyl group is not connected to any hydrogen atoms. Acetone, the simplest kind of ketone, is important as an intermediate in cell metabolism and is the active ingredient in most nail polish removers.

In an ether, an oxygen atom serves as a link in a hydrocarbon chain. Ethers In an ether, an oxygen atom serves as a link in a hydrocarbon chain. Ethers are highly explosive. For this reason, they are sometimes used as an engine starting fluid. In the laboratory, ethers are used as solvents for fats, oils, resins, and alkaloids.

Esters In an ester, an ester group (COO) serves as a link in a hydrocarbon chain. Esters are found in all natural fats and oils. It is frequently prepared synthetically for commercial use as artificial fruit essences and other flavorings, components of perfume, household cleaners, textile processes and dry cleaning formulations

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