Chemistry · Grades 9–12
Monomers, repeat units and polymer properties
Connect long-chain structure with properties without universal recyclability claims.
Learn the idea
Polymer
A polymer contains many repeating structural units derived from smaller starting molecules.
Addition
In a simple alkene addition polymer model, the double bond opens into backbone single bonds.
Condensation
Some step-growth polymer examples form links while releasing small molecules; not every step-growth process does.
Properties
Chain length, branching, cross-linking and intermolecular interactions affect material properties.
Worked examples
What is a monomer?
Monomers are building blocks for polymer structures.
A small molecule that can contribute units to a polymer.
In the simple addition-polymer model of ethene, what happens to C=C bonds?
The repeated carbon framework is retained with changed bonding.
They become backbone single-bond connections.
Check your understanding
A stated repeat unit has two carbon atoms. How many carbons are in 30 such repeat units, ignoring end groups?
Why can two polymers with similar compositions have different flexibility?
Which feature generally restricts chains from sliding past one another?
- Erasing every bond.
- Cross-links between chains.
- Only a different written name.
Answers and marking notes
Answers and marking notes
- 60
30 × 2 = 60 carbon atoms.
- Chain arrangement, branching, cross-linking and interactions can differ.
Structure beyond elemental composition matters.
- Cross-links between chains.
Cross-links connect chains and constrain motion.
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Independent educational review required. Grade bands are approximate; these are not officially aligned curricula.