Polymer basics: Choose the correct statement(s) describing monomers, polymers, macro-molecules, and polymeric materials.
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AA substance consisting of one primary chemical building block is a monomer.
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BA polymer consists of many (often thousands of) monomer units chemically joined.
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CA single polymer molecule is called a macro-molecule.
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DA polymeric material is composed of a large number of long-chain molecules.
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EAll of the above.
Answer
Correct Answer: All of the above.
Explanation
Introduction / Context:Polymer terminology is foundational for engineers choosing plastics, rubbers, and resins. Knowing what a monomer is and how it forms long chains clarifies why polymers behave differently from metals and ceramics in thermal and mechanical contexts.
Given Data / Assumptions:
- Common definitions from materials science are applied.
- Examples: ethylene (monomer) to polyethylene (polymer).
- Focus on structural concepts rather than processing details.
Concept / Approach:A monomer is a small molecule capable of polymerization. Polymerization links many monomers into long chains called macro-molecules. Bulk polymeric materials contain vast ensembles of these long chains, which tangle, crystallize partially, and determine properties such as toughness and creep.
Step-by-Step Solution:Option A: Correct — monomer is the basic repeating unit precursor.Option B: Correct — polymers contain many repeating units; degrees of polymerization can be in the hundreds to thousands (or more).Option C: Correct — a single very large polymer chain is a macro-molecule.Option D: Correct — a polymeric material is a bulk aggregation of such chains.Therefore E (“All of the above”) is true.
Verification / Alternative check:Introductory texts consistently define polymers with these terms and relationships.
Why Other Options Are Wrong:Any single statement alone is incomplete; together they present the full picture.
Common Pitfalls:Assuming all polymers have identical chain lengths; distributions matter (polydispersity).
Final Answer:All of the above.