Classify each hydrocarbon as an alkane, alkene, or alkyne. a. \(\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}-\mathrm{CH}_{3}\) b. \(\mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{2}-\mathrm{CH}_{3}\) c. \(\mathrm{HC} \equiv \mathrm{C}-\mathrm{CH}_{3}\) d. \(\mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{3}\)

Alkanes are hydrocarbons that form the simplest class among organic compounds. They are characterized by having only single bonds between carbon atoms, which results in a saturated molecular structure. The general formula for alkanes is \( C_nH_{2n+2} \), where \(n\) represents the number of carbon atoms.

For example, in part b, \( \mathrm{H}_{3}C-CH_{2}-CH_{3} \), and part d, \( \mathrm{H}_{3}C-CH_{2}-CH_{2}-CH_{3} \), of the exercise, each carbon is connected by single bonds to other carbons or hydrogens. These structures fit the alkane profile, demonstrating the structural simplicity that is typical of alkanes.

In contrast to alkanes, alkenes are unsaturated hydrocarbons that contain at least one carbon-carbon double bond. This characteristic imparts different chemical properties to alkenes versus alkanes. The presence of a double bond not only affects the alkene's reactivity but also its geometry, leading to the possibility of cis-trans isomerism. The general formula for alkenes is \( C_nH_{2n} \).

In the given example a, \( \mathrm{H}_{2}C=CH-CH_{3} \), the presence of the double bond between two carbon atoms clearly classifies this compound as an alkene. Double bonds are pivotal in organic chemistry, as they open up a compound to new chemical reactions like polymerization.

Taking a step further in complexity, alkynes are hydrocarbons with at least one carbon-carbon triple bond. These triple bonds are composed of a sigma bond and two pi bonds, and they make alkynes even more chemically reactive than alkenes. Alkynes have the general formula \( C_nH_{2n-2} \), indicating an even lower ratio of hydrogen to carbon than in alkenes.

In the given example c, \( HC\equiv C-CH_{3} \), the compound includes a carbon-carbon triple bond, which is the defining feature of an alkyne. Alkynes are known for their distinctive reactions, such as the ability to add across the triple bond in a process known as hydrogenation.

Organic chemistry is the branch of chemistry focused on the study of carbon-containing compounds and their transformations. It covers a vast array of substances, from simple molecules like methane to complex biological macromolecules. Understanding organic chemistry is essential, as it provides the basis for studying life processes, creating pharmaceuticals, and designing new materials.

The classification of hydrocarbons into alkanes, alkenes, and alkynes is foundational in organic chemistry because it helps predict the behavior and reactions of these compounds. Recognizing the structural differences and similarities among hydrocarbons is critical for understanding their potential reactions and applications.

Chemical bonding is a core concept in chemistry that explains how atoms connect to form molecules. The bonds between atoms can be ionic, covalent, or metallic, with covalent bonds being paramount in organic chemistry. In covalent bonding, atoms share electron pairs to achieve stability, exhibiting different properties based on the bond's nature. Single, double, and triple bonds refer to the sharing of one, two, or three pairs of electrons, respectively.

Through the step-by-step solution, students learn to identify the type of bonds present in hydrocarbons. This skill is not only crucial in classifying hydrocarbons but also influences their physical properties and the types of reactions they can undergo. For instance, the increased electron density in double or triple bonds compared to single bonds makes them more reactive. Understanding chemical bonds is essential for mastering the complexities of organic molecules.