A compound chemical is a combination of two or more elements that are chemically bonded together. An ESTER is a type of compound chemical that is formed when an acid reacts with an alcohol, and is composed of a carbonyl group and an alkyl group. An isomer is another type of compound chemical that has the same molecular formula as another compound, but has a different arrangement of atoms in its structure. Lastly, a LYE is a type of compound chemical that is composed of sodium hydroxide or potassium hydroxide, and is used in a variety of industrial and household applications.