Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

What characterizes an alkane?

1. Contains at least one carbon-carbon double bond

2. Contains at least one carbon-carbon triple bond

3. Saturated hydrocarbon containing only single bonds between carbon atoms

4. Has a ring structure based on benzene

The correct answer is: Saturated hydrocarbon containing only single bonds between carbon atoms

An alkane is characterized as a saturated hydrocarbon, which means it contains only single bonds between carbon atoms. In alkanes, every carbon atom is bonded to the maximum number of hydrogen atoms possible, adhering to the formula CnH2n+2. This structure results in a molecule that is fully "saturated" with hydrogen, having no double or triple bonds to other carbons. The presence of only single bonds is significant because it lends alkanes their stability. This stability is a hallmark trait of alkanes, distinguishing them from other types of hydrocarbons, such as alkenes and alkynes, which contain double and triple bonds, respectively. Furthermore, alkenes and alkynes would be characterized by the presence of at least one carbon-carbon double or triple bond, which is not applicable to alkanes. Other options that suggest ring structures, such as those based on benzene, belong to a different category of compounds known as aromatic hydrocarbons and do not define alkanes. Thus, the correct characterization of alkanes is that they are saturated hydrocarbons containing only single bonds between carbon atoms.