Organic chemistry is the study of compounds that contain C-C or C-H bonds. You might wonder, “Why devote a whole field of study to just carbon compounds?”
There are more compounds that contain carbon than compounds that don’t.
The compounds with carbon can be very large and complex.

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Organic chemistry is a major part of our lives, from the simple sugars and amino acids to the complex enzymes and huge DNA molecules. Organic chemistry is involved in the development of the food you eat; the clothes you wear; the plastics and polymers that are all around you; the medicines you use; your fuels, pesticides, poisons, soaps and detergents.
The properties of organic compounds differ from those of inorganic compounds. Organic compounds have

low melting points
low boiling points
soluble organic solvents rather than water
poor electrical conductivity.

Organic reactions are usually slow and produce low yields of product because of the many side reactions that can occur.
Although, there are millions of known organic compounds, the elements they contain are relatively few. Besides, carbon and hydrogen, there is oxygen, nitrogen, sulfur, phosphorus and the halogens.
The chemical and physical properties of these compounds are related to the structures of their molecules. Thus, the key to understanding organic chemistry is an understanding molecular structure and chemical bonding.

Carbon
Remember, carbon has four valence electrons and can obtain a stable configuration by forming four covalent bonds. Also, carbon is unique in that it bonds easily with other carbon atoms, while other elements rarely bond with like atoms. Thus, carbon can form long chains, branched chains, rings and rings with chains for a vast variety of compounds.

Hydrocarbons
Many organic compounds consist of only carbon and hydrogen atoms and are known as hydrocarbons. Hydrocarbons are subdivided into two groups-aliphatic hydrocarbons and aromatic hydrocarbons. The aliphatic hydrocarbons that are acyclic (chains) or cyclic (rings) and contain only sigma bonds are saturated hydrocarbons. Those that have both sigma and pi bonds are known as unsaturated hydrocarbons. The aromatic hydrocarbons are cyclic hydrocarbons that contain three double bonds.
The aliphatic hydrocarbons consist of chains of carbon atoms with hydrogen attached to the outsides of the chain. Since carbon can form single, double and triple bonds three types of aliphatic hydrocarbons are possible-alkanes, alkenes and alkynes.

Alkanes
Alkanes are hydrocarbons in which there are only single covalent bonds between the carbon atoms. The general formula for alkanes is Cn H2n+2, where n is the number of carbon atoms in the chain. The length of the carbon chain tends to affect the physical properties such as boiling point and melting point due to the variation in strength of the dipersion forces.
Naming alkanes is simple, just choose the prefix that indicates the number of carbons in the chain and add the suffix -ane to the end.

Alkenes
Alkenes are compounds in which there is at least one double covalent bond between the carbon atoms. The general formula for alkenes is Cn H2n, where n is the number of carbon atoms in the chain. To name alkenes, indicate where the double bond is by numbering the carbon chain starting with the end closest to the double bond. Then use a prefix to indicate the number of carbons in the chain and add the suffix -ene to the end. For chains that contain two double bonds, list the location of the double bonds and add the suffix -adiene to the end.
Alkynes
Alkynes are compounds in which there is at least one double covalent bond between the carbon atoms. The general formula for alkenes is CnH2n-2, where n is the number of carbon atoms in the chain. To name alkynes, indicate where the triple bond is by numbering the carbon chain starting with the end closest to the triple bond.