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Polymers: Quiz

Seven questions on monomers, repeat units, addition and condensation polymers and degree of polymerization, with explanations.

7 questionsIntermediate

7 questions

  1. Question 1EasyWhich monomer can form an addition polymer?
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    Answer: propene

    Addition polymerization needs a C=C double bond; only propene has one.

  2. Question 2MediumWhat is the repeat unit of poly(propene)?
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    Answer: –[CH₂–CH(CH₃)]–

    The C=C opens into a single bond; the CH₃ stays as a branch. A three-carbon main chain is wrong.

  3. Question 3EasyWhich polymer is a condensation polymer?
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    Answer: nylon-6,6

    Nylon forms from a dicarboxylic acid and a diamine with loss of water. The others are addition polymers of alkenes.

  4. Question 4EasyWhat small molecule is released when a polyester forms?
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    Answer: H₂O

    Each ester link forms from –COOH and –OH, releasing one water molecule.

  5. Question 5MediumWhich pair of monomers can form a polyamide?
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    Answer: a diamine and a dicarboxylic acid

    –NH₂ and –COOH groups join to form amide (–CONH–) links. A diol and a diacid give a polyester.

  6. Question 6MediumA poly(chloroethene) chain has a molar mass of 6.25 × 10⁴ g/mol (repeat unit 62.49 g/mol). About how many repeat units does it have?
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    Answer: 1.00 × 10³

    n = 6.25 × 10⁴ g/mol ÷ 62.49 g/mol = 1.00 × 10³.

  7. Question 7HardWhy can thermoplastics be recycled by melting but thermosets cannot?
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    Answer: thermoplastic chains are separate and slide apart on heating; thermosets are cross-linked

    Covalent cross-links between chains in thermosets stop them melting; they char instead.