AQA GCSE Chemistry (8462), Higher tier · Bonding, structure and the properties of matter › Bonding, structure and properties
Practise Polymers. 12 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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What name is given to the small molecules that join together to make a polymer?
monomers
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
Poly(ethene) is a polymer.
(a) Complete the sentence. Tick (✓) one box. Polymers have ................ molecules.[1]
very large
very small
charged
single-atom
(b) What type of bond joins the atoms within a polymer molecule? Tick (✓) one box.[1]
Covalent
Ionic
Metallic
Intermolecular
(c) Why is poly(ethene) a solid at room temperature? Tick (✓) one box.[1]
The intermolecular forces between the polymer molecules are relatively strong.
The polymer molecules are held together by ionic bonds.
Poly(ethene) contains delocalised electrons.
Poly(ethene) molecules are very small.
(d) What name is given to the small molecules that join together to make a polymer?[1]
Show the answer and mark scheme
(a)Answer: very large
(b)Answer: Covalent
(c)Answer: The intermolecular forces between the polymer molecules are relatively strong.
(d)Answer: monomers
monomers
Question 2Medium2 marks
A student says: 'Poly(ethene) is a solid at room temperature because its covalent bonds are very strong.'
Evaluate the student's statement.[2]
Show the answer and mark scheme
Answer: The covalent bonds in the chains are strong, but they are not broken when poly(ethene) melts. Poly(ethene) is a solid because its molecules are very large, so the intermolecular forces between them are relatively strong.
the covalent bonds within the chains are strong, but they are not broken when poly(ethene) melts / softens
it is a solid because the intermolecular forces between the (very large) polymer molecules are relatively strong
Question 3Hard6 marks
Poly(ethene) is made from ethene. The repeating unit of poly(ethene) is –CH2–CH2–, which has a relative formula mass of 28.
(a) A poly(ethene) molecule contains 4000 repeating units. Calculate the relative formula mass of the molecule.[2]
(b) A sample of poly(ethene) contains molecules with different numbers of repeating units. Suggest why the sample softens over a range of temperatures, rather than melting at one temperature.[2]
(c) Explain why the covalent bonds in the poly(ethene) chains are not broken when poly(ethene) melts.[2]
Show the answer and mark scheme
(a)Answer: 112 000
4000 × 28
112 000
(b)Answer: The molecules have different lengths, so the intermolecular forces between them have different strengths and are overcome at different temperatures.
the molecules have different lengths / sizes
so the intermolecular forces have different strengths / need different amounts of energy to overcome
(c)Answer: Only the intermolecular forces between the chains are overcome; the covalent bonds are much stronger.
only the intermolecular forces between the chains are overcome
covalent bonds are much stronger / need much more energy to break