Gasoline is a common fuel. most gas stations sell multiple grades of gasoline. these grades are distinguished by their octane content. octane (c8h18) is one of the components of gasoline, which may also contain many other types of hydrocarbons (such as decane, dodecane, and nonane). the fraction of gasoline that is made up of octane affects how the gasoline burns in a car’s engine. higher octane ratings are typically more expensive and can improve performance in certain types of engines. is gasoline a compound or a mixture?