Definition of Organic Compounds. Organic compounds are those that contain carbon, and organic chemistry is the study of those compounds. Inorganic chemistry is the study of the elements and all non-carbon compounds. Carbon compounds are of tremendous everyday importance to life on earth and are the basis of all life processes.

Comparison of Properties of Organic and Inorganic Compounds

Bonding Characteristics Large numbers of organic compounds are possible because carbon atoms link together ( catenate) to form chains and networks via covalent bonding.

Isomerism. An additional reason for the existence of so many organic compounds is the phenomenon of isomerism. Isomers are compounds which have the same molecular formula but different arrangements of atoms.

Functional Groups. All organic compounds are grouped into classes based upon characteristic features called functional groups identified by their atoms and types of bonds. Functional groups determine chemicxal and phsical properties. An important concept throughout this semester is that STRUCURE DETERMINES FUNCTION. Compounds with their functional groups are represented by two types of structural formulas. Expanded structural formulas show all the covalent bonds, while condensed structural formulas show no covalent bonds or only selected bonds.

Alkane Structures. Alkanes are hydrocarbons that contain only single covalent bonds and can be represented by the formula CH2n+2 .Alkanes possess a three-dimensional geometry in which each carbon is surrounded by four bonds directed to the corners of a tetrahedron. The bond angles are 109.5 degrees. Methane, the simplest alkane, is an important fuel (natural gas) and a chemical feedstock for the preparation of other organic compounds. The number of structural isomers possible for an alkane increases dramatically with the number of carbon atoms present in the molecule.

Conformations of Alkanes. Rotation about the single bonds between carbon atoms allows alkanes to exist in many different conformations. When an alkane is drawn using only 'two dimensions, the structure can be represented in a variety of ways as long as the order of bonding is not changed.

Alkane Nomenclature. Some simple alkanes are known by common names. More complex compounds are usually names using the systematic lUPAC system. The characteristic lUPAC ending for alkanes is -ane.

Cycloalkanes. These are alkanes in which the carbon atoms form a ring. The prefix cyclo- is used in the names of these compounds to indicate their cyclic nature.

The Shape of Cycloalkanes. The carbon atom rings of cycloalkanes are usually shown as planar, although only the carbon ring in cyclopropane is planar. Because rotation about the single bonds in the ring is restricted, certain disubstituted cycloalkanes can exist as geometric (cis/trans) isomers. Bond angles are often distorted in cycloalkanes leading to ring strain. The greater the deviation from the terahedral angle of 109.5 degrees, the greater is the ring strain and the less stable is the cycloalkane. Cyclohexane avoids this by puckering to form theboat or the chair conformation.

Physical Properties of Alkanes. The physical properties of alkanes are typical of all hydrocarbons: nonpolar, insoluble in water, less dense than water and increasing melting and boiling points with increasing molecular weight.

Alkane Reactions. Alkanes are relatively unreactive and remain unchanged by most reagents. The reaction that is most significant is combustion.