Which term best describes synthetic polymers such as polyethylene, polystyrene, polypropylene, polyvinyl chloride, and polytetrafluoroethylene?

• A. Metal
• B. Plastic
• C. Ceramic
• D. Glass

Answer: (B)

These materials are polymers—long chains built from repeating units. The examples listed are synthetic polymers, made in industry rather than occurring naturally. The term plastic is used for these materials because plastics are a broad class of polymers that can be molded or shaped into a wide variety of forms, which matches how polyethylene, polystyrene, polypropylene, polyvinyl chloride, and polytetrafluoroethylene are used. They’re not metals, which rely on metallic bonds and have different properties; not ceramics, which are typically inorganic and brittle; and not glass, which is an amorphous solid. So, plastic is the best description for these synthetic polymers.