We begin our study of organic chemistry with the alkanes, compounds containing only two elements, carbon and hydrogen, and having only single bonds. There are several other kinds of hydrocarbons, distinguished by the types of bonding between carbon atoms and by the properties that result from that bonding. We will first examine hydrocarbons with double bonds, with triple bonds, and with a special kind of bonding called aromaticity. Then we will study some compounds considered to be derived from hydrocarbons by replacing one or more hydrogen atoms with an oxygen-containing group. Finally, we focuse on organic acids and bases, after which we will be ready to look at the chemistry of life itself—biochemistry—in the remaining five chapters. 12.1: Organic Chemistry Today organic chemistry is the study of the chemistry of the carbon compounds, and inorganic chemistry is the study of the chemistry of all other elements. Organic chemistry is the study of carbon compounds, nearly all of which also contain hydrogen atoms. 12.2: Structures and Names of Alkanes Simple alkanes exist as a homologous series, in which adjacent members differ by a \(CH_2\) unit. 12.3: Branched-Chain Alkanes Alkanes with four or more carbon atoms can exist in isomeric forms. 12.4: Condensed Structural and Line-Angle Formulas Condensed chemical formulas show the hydrogen atoms (or other atoms or groups) right next to the carbon atoms to which they are attached. Line-angle formulas imply a carbon atom at the corners and ends of lines. Each carbon atom is understood to be attached to enough hydrogen atoms to give each carbon atom four bonds. 12.5: IUPAC Nomenclature Alkanes have both common names and systematic names, specified by IUPAC. 12.6: Physical Properties of Alkanes Alkanes are nonpolar compounds that are low boiling and insoluble in water. 12.7: Chemical Properties of Alkanes The alkanes and cycloalkanes, with the exception of cyclopropane, are probably the least chemically reactive class of organic compounds. Alkanes contain strong carbon-carbon single bonds and strong carbon-hydrogen bonds. The carbon-hydrogen bonds are only very slightly polar. Alkanes can be burned, alkanes can react with some of the halogens, breaking carbon-hydrogen bonds, and alkanes can crack by breaking the carbon-carbon bonds. 12.8: Halogenated Hydrocarbons The replacement of an hydrogen atom on an alkane by a halogen atom—F, Cl, Br, or I—forms a halogenated compound. 12.9: Cycloalkanes Many organic compounds have cyclic structures. 12.10: Organic Chemistry - Alkanes Hydrocarbons are the simplest organic compounds, but they have interesting physiological effects. These effects depend on the size of the hydrocarbon molecules and where on or in the body they are applied. Alkanes of low molar mass—those with from 1 to approximately 10 or so carbon atoms—are gases or light liquids that act as anesthetics. 12.11: Organic Chemistry: Alkanes Select problems and solutions to chapter. 12.12: Organic Chemistry: Alkanes Summary of Chapter.