Final answer:
The statement that hydrocarbons are nonpolar compounds containing carbon and hydrogen is true. Hydrocarbons can be gases, liquids, or solids at room temperature depending on their molecular size and structure, and they include four main classes: alkanes, alkenes, alkynes, and aromatic compounds.
Step-by-step explanation:
Hydrocarbons are nonpolar compounds containing carbon and hydrogen atoms. This statement is true as most hydrocarbons exhibit nonpolarity due to the similar electronegativities of carbon (C) and hydrogen (H) atoms. Hydrocarbons like methane and ethane are gases at room temperature, while larger hydrocarbons such as hexane and octane are liquids.
Alkanes, alkenes, alkynes, and aromatic compounds are the four main classes of hydrocarbons. These classes differ in their carbon-carbon bonding: alkanes contain single bonds, alkenes have at least one double bond, alkynes have at least one triple bond, and aromatic hydrocarbons contain benzene rings. The properties of hydrocarbons, such as physical state and solubility, are greatly influenced by the length of the carbon chain and type of carbon-carbon bonds.