10 questions · Form 5 Chemistry Bab 4: Polymer Chemistry
What structural feature prevents thermosetting plastics from melting upon heating?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. What structural feature prevents thermosetting plastics from melting upon heating?
Answer: C
Strong covalent cross-links hold polymer chains firmly together in a 3D network, preventing the plastic from melting when heated.
2. Which type of polymer can be repeatedly melted upon heating and remoulded without undergoing chemical decomposition?
Answer: C
Thermoplastics have linear or branched chains with weak intermolecular forces, allowing them to melt upon heating and be remoulded repeatedly.
3. Which of the following synthetic polymers is a polyamide?
Answer: B
Nylon is a polyamide formed through condensation polymerisation between dicarboxylic acids and diamines.
4. Which monomer is used to produce polystyrene?
Answer: C
Polystyrene is synthesized through the addition polymerisation of phenylethene, commonly called styrene.
5. What hazardous toxic gas is released when Polyvinyl chloride (PVC) waste is incinerated?
Answer: B
PVC contains chlorine atoms; burning PVC releases toxic, corrosive hydrogen chloride (HCl) gas.
6. Terylene is a synthetic polyester. Which two functional groups react together to form a polyester link?
Answer: A
Polyesters are formed when dicarboxylic acids containing -COOH groups react with diols containing -OH groups.
7. What is the systematic IUPAC name for the monomer of natural rubber?
Answer: B
The monomer of natural rubber (isoprene) has the systematic IUPAC name 2-methylbuta-1,3-diene.
8. Why does adding ethanoic acid cause latex to coagulate?
Answer: B
Ethanoic acid releases H⁺ ions that neutralise the negative charges on the protein membrane, allowing rubber particles to collide, rupture, and coagulate.
9. Which of the following is a naturally occurring polymer?
Answer: C
Protein is a natural polymer made up of amino acid monomers. Polythene, PVC, and Nylon are synthetic polymers.
10. What functional group must be present in monomer molecules to undergo addition polymerisation?
Answer: C
Addition polymerisation requires monomers with unsaturated carbon-carbon double bonds (C=C).