iGCSE Chemistry 0620 Extended - 11.8 Polymers- Exam Style Questions Paper 2- New Syllabus
▶️ Answer/Explanation
To form a condensation polymer with a dicarboxylic acid, the monomer must have two functional groups that can react with the −COOH groups. This means the monomer must be a diol (two −OH groups) or a diamine (two −NH₂ groups) to form polyesters or polyamides respectively. Only monomers with two reactive functional groups in a 1:1 ratio can form polymers. Of the four monomers shown, 2 satisfy this requirement.
✅ Answer: (B)
✅ Answer: (B)
▶️ Answer/Explanation
Addition polymers form by the breaking of the C=C double bond. The repeat unit has the backbone carbon chain with the functional group attached. The correct repeat unit (often represented as -CH(COOH)-CH₂-) corresponds to option B in the original mark scheme.
✅ Answer: (B)
✅ Answer: (B)
▶️ Answer/Explanation
Correct Answer: D
Explanation: Proteins are natural polyamides formed by condensation polymerisation of amino acid monomers. In condensation polymerisation, a small molecule (usually water) is eliminated as the polymer forms. When two amino acids join, a water molecule is released, forming a peptide bond. Addition polymers (like poly(ethene)) contain only single C-C bonds in the main chain and can contain atoms other than C and H (e.g., PVC contains Cl). Polyesters are made from a dicarboxylic acid and a diol, not a diamine (polyamides use diamines).
✅ Water is an additional product in the formation of a protein from amino acids.