Plastics are examples of:
Try it first: pick an option, then read the explanation.
Understanding the Fundamental Nature of Plastics
This question asks for the broad scientific category to which all plastics belong. The answer lies in their molecular structure.
Polymer: A large molecule, or macromolecule, composed of many repeating subunits called monomers. The word comes from Greek: poly- meaning "many" and -mer meaning "part." Plastics are synthetic or semi-synthetic materials made from these long polymer chains.
Detailed Analysis of the Options
Let's evaluate each term to find the most accurate classification for plastics.
(b) polymeric materials
Why it's correct: This is the correct, all-encompassing scientific term. All plastics, from PVC and polyethylene to Bakelite and nylon, are polymers. Their properties are determined by the type of monomer used, the length of the polymer chains, and how those chains are linked together. "Polymeric materials" is the fundamental classification.
(a) anhydrides
Why it's incorrect: An anhydride is a specific type of chemical compound that is formed by the removal of a water molecule from another compound. While some monomers used to make plastics might be related to anhydrides, it is not the term for the final plastic material itself.
(c) ceramic materials
Why it's incorrect: Ceramics are inorganic, non-metallic solids, typically formed by the action of heat. Examples include clay, glass, and cement. Their chemical bonding and structure are fundamentally different from the organic, long-chain molecules of plastics.
(d) elastomers
Why it's incorrect: An elastomer is a specific *type* of polymer that exhibits high elasticity—it can be stretched significantly and return to its original shape. Rubber is the classic example. While all elastomers are polymers, not all polymers (and therefore not all plastics) are elastomers. For example, rigid PVC is a plastic but not an elastomer. This term is too specific.
Study Tips for Material Classification
- Plastics = Polymers: This is the most important and direct association to memorize.
- Think in Categories:
- Broadest Category: Polymeric Materials
- Sub-category: Plastics (e.g., PVC, PET)
- Sub-category: Elastomers (e.g., Natural Rubber)
- Sub-category: Fibers (e.g., Nylon, Polyester)
- Remember the "Poly" Prefix: Many plastic names start with "poly-" (polyethylene, polypropylene, polystyrene), which is a direct clue that they are polymers.