Iowa Barber Practice Exam

An example of a pure substance is a material that is made up of only one type of atom or molecule. Options B, C, and D are not considered pure substances because they are composed of different types of atoms and molecules. B is a mixture of hydrogen and oxygen atoms, C is a polymer made up of different monomer units, and D is a mixture of gases such as nitrogen, oxygen, and carbon dioxide. Therefore, A, aluminum foil, is the only pure substance among the choices given.