Polymer Examples in Chemistry

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Polymer.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.

Concept Recap

A polymer is a very large molecule made by linking many smaller repeating units called monomers into long chains or networks.

A polymer is like a long molecular chain built from many repeating links.

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How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Polymer starts by identifying the carbon skeleton, functional group, and repeating pattern if present.

Common stuck point: Students often know a formula related to polymer but skip the recognition step: Am I using carbon structure, bonds, functional groups, or repeating units to explain the molecule? That leads to a correct-looking substitution attached to the wrong chemical model.

Sense of Study hint: Ask: Am I using carbon structure, bonds, functional groups, or repeating units to explain the molecule?

Worked Examples

Example 1

easy
A student sees 'PET' on a soda bottle. Worked example: explain why PET (polyethylene terephthalate) is classified as a polymer.

Answer

It is a long chain of terephthalate ester repeat units\text{It is a long chain of terephthalate ester repeat units}

First step

1
PET stands for poly(ethylene terephthalate).

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Example 2

medium
Worked example: nylon-6,6 is made by linking diamine and diacid monomers, eliminating water at each link. What type of polymer is this?

Example 3

medium
Worked example: a teacher labels Teflon (−CF2−CF2−-CF_2-CF_2-) as a polymer. Identify its monomer and the type of polymerization.

Example 4

hard
Worked example: 0.50 mol of ethylene polymerizes completely into polyethylene. Predict the total mass of polymer formed (ethylene molar mass = 28 g/mol).

Example 5

challenge
Worked example: a copolymer is made with ethylene (mass 28) and propylene (mass 42) in a 3:1 mole ratio. The chain has 400 total repeat units. Find the polymer's molar mass.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
A polymer is made by linking many small repeating units called what?

Example 2

easy
Is a polymer a small molecule or a very large molecule?

Example 3

easy
Polyethylene is made from many ethylene units. Is ethylene a monomer or a polymer?

Example 4

easy
Are all polymers synthetic plastics?

Example 5

easy
Is starch a polymer?

Example 6

easy
The repeating unit in a polymer comes from which kind of molecule?

Example 7

easy
Does the repeating structure of a polymer affect properties like strength and flexibility?

Example 8

easy
Proteins are polymers of which monomer?

Example 9

medium
If 100 ethylene monomers join to form a chain, roughly how many repeat units does the polymer have?

Example 10

medium
Why does a polymer like polyethylene have a much higher melting point than its single ethylene monomer?

Example 11

medium
A student says 'a monomer and its polymer are the same substance, just different sizes.' Correct this.

Example 12

medium
Why is the repeating-unit picture useful for predicting a polymer's formula?

Example 13

medium
Cellulose and starch are both polymers of glucose, yet have different properties. What likely differs?

Example 14

medium
Why are many polymers flexible while small molecules of the same atoms are not?

Example 15

medium
DNA and proteins are both polymers. What does this tell you about how life builds large molecules?

Example 16

medium
Is DNA a polymer? Identify its monomer.

Example 17

medium
Why can recycling plastics be difficult given that they are polymers?

Example 18

challenge
Polyethylene's repeat unit is −CH2−CH2−-CH_2-CH_2- (mass 28 g/mol). A sample chain has molar mass about 28000 g/mol. Roughly how many repeat units (degree of polymerization) does it have?

Example 19

challenge
Two polyethylene samples have the same chemistry but one is rigid and one is flexible. Using polymer structure, give a plausible reason.

Example 20

challenge
If a polymer chain is built from a monomer of mass 100 g/mol and the polymer has a molar mass of 50000 g/mol, find the degree of polymerization and explain what it represents.

Example 21

easy
Is rubber from a rubber tree a natural polymer?

Example 22

easy
Which of these is a polymer: water, oxygen, cellulose, methane?

Example 23

easy
Polypropylene is made from propylene (C3H6C_3H_6). What is the monomer's name?

Example 24

easy
Are silk and wool natural polymers?

Example 25

medium
A polymer chain has 250 repeating units, each of mass 104 g/mol. Estimate the polymer's molar mass.

Example 26

medium
Why does polystyrene (chain of styrene units) feel rigid while natural rubber (chain of isoprene units) feels stretchy?

Example 27

medium
Polyethylene is formed from ethylene (CH2=CH2CH_2=CH_2) opening its double bond and linking. Is this addition or condensation polymerization?

Example 28

medium
A polymer's average molar mass is 84000 g/mol, and its monomer has mass 168 g/mol. What is the degree of polymerization?

Example 29

medium
PVC's repeat unit is −CH2−CHCl−-CH_2-CHCl- (mass 62.5 g/mol). What is the molar mass of a chain with 800 repeat units?

Example 30

medium
Why does cooking an egg permanently change its proteins?

Example 31

medium
A polymer is heated and softens, then cools and hardens again, repeatedly. Is it a thermoplastic or thermoset?

Example 32

medium
Glycogen and starch are both polymers of glucose used to store energy. What does this tell you about why life uses polymers?

Example 33

medium
In a condensation polymer, 200 monomer units each release one water molecule as they join (199 links). Roughly how many water molecules are produced?

Example 34

hard
A polystyrene sample has molar mass 1.04×1051.04 \times 10^5 g/mol. The styrene monomer has mass 104 g/mol. Find the degree of polymerization.

Example 35

hard
A nylon-6,6 polymer has a degree of polymerization of 100. Each repeat unit (after water loss) has mass 226 g/mol. Estimate the molar mass.

Example 36

hard
A protein is 150 amino acids long. Each peptide bond formation releases one water molecule. How many water molecules are released?

Example 37

hard
Cellulose and starch are both glucose polymers but cellulose is rigid and indigestible while starch is digestible. Briefly explain in terms of polymer structure.

Example 38

hard
A polyester sample is found to have molar mass 25600 g/mol. The repeat unit mass is 192 g/mol. How many repeat units per chain?

Example 39

challenge
A polymer chain made of monomer mass 100 g/mol has number-average molar mass 50000 g/mol. If 0.10 mol of monomer was used, how many polymer chains formed (assuming all monomer reacted)?
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Background Knowledge

These ideas may be useful before you work through the harder examples.

organic chemistryhydrocarbon