Problem 1: Identify the polymer from its repeat unit

Given: A polymer has repeat unit –[NH–(CH2)6–NH–CO–(CH2)4–CO]– Question: Identify the polymer and name its two monomers.

Solution: Step 1: Identify the linkage. The unit contains –CO–NH– → amide linkage → polyamide (nylon type). Step 2: Count carbons in each segment. –NH–(CH2)6–NH– = 6 carbons between two NH groups → hexamethylenediamine (H2N–(CH2)6–NH2). Step 3: –CO–(CH2)4–CO– = 4 CH2 groups + 2 carbonyl carbons = 6 total → adipic acid (HOOC–(CH2)4–COOH). Step 4: Both monomers have 6 carbons → Nylon-6,6 (the "6,6" refers to 6C in each monomer). Answer: Nylon-6,6. Monomers: hexamethylenediamine + adipic acid.