Final answer:
Butane is called a saturated hydrocarbon because it contains only single covalent bonds between its carbon atoms. This means that each carbon atom in butane is bonded to four other atoms (hydrogen or carbon), maximizing the number of hydrogen atoms it can bond with.
Step-by-step explanation:
Butane is called a saturated hydrocarbon because it contains only single covalent bonds between its carbon atoms. Saturated hydrocarbons, or alkanes, have the maximum number of hydrogen atoms bonded to each carbon atom, according to the rules of covalent bonds. This means that each carbon atom in butane is bonded to four other atoms (hydrogen or carbon), maximizing the number of hydrogen atoms it can bond with.