Practise Condensation polymerisation. 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.
Cover the answers and test yourself. The app has these as flashcards that come back just before you'd forget them.
Ethane diol and hexanedioic acid react to form a polyester. The monomers can be shown as: ethane diol: HO–□–OH hexanedioic acid: HOOC–▭–COOH Name the functional group in each monomer.
Calculate the relative formula mass of the repeating unit of this polyester.
158
Name the small molecule that is released each time the two monomers join together.
water
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy3 marks
A polyester is made from two different monomers. One monomer has two alcohol (–OH) groups. The other monomer has two carboxylic acid (–COOH) groups.
(a) What type of polymerisation is used to make a polyester? Tick (✓) one box.[1]
Addition polymerisation
Condensation polymerisation
Cracking
Fermentation
(b) Name the small molecule that is released each time the two monomers join together.[1]
(c) Poly(ethene) is made from ethene by addition polymerisation. Give one difference between the way poly(ethene) is made and the way a polyester is made.[1]
Show the answer and mark scheme
(a)Answer: Condensation polymerisation
(b)Answer: water
water / H2O
(c)Answer: Poly(ethene) is made from only one type of monomer, but a polyester is made from two different monomers.
poly(ethene) is made from one type of monomer but a polyester is made from two different monomers / no small molecule is released when poly(ethene) forms, but water is released when a polyester forms
Question 2Medium6 marks
Ethane diol and hexanedioic acid react to form a polyester. The monomers can be shown as: ethane diol: HO–□–OH hexanedioic acid: HOOC–▭–COOH
(a) Name the functional group in each monomer.[2]
(b) Name the small molecule that is lost each time two monomers join together.[1]
(c) Complete the equation to show the polyester formed. n HO–□–OH + n HOOC–▭–COOH → ________________ + 2n H2O[2]
(d) Explain why this reaction is described as condensation polymerisation.[1]
ethane diol: –OH / hydroxyl / alcohol group (two of them)
hexanedioic acid: –COOH / carboxylic acid group (two of them)
(b)Answer: Water
water
(c)Answer: –[O–□–O–CO–▭–CO]n– (each CO drawn as C=O)
a repeating unit containing both blocks joined by an ester link: –O–□–O–C(=O)–▭–C(=O)–
shown in brackets with n (and bonds at each end)
(d)Answer: A small molecule (water) is lost each time two monomers join to make the polymer.
a small molecule (water) is lost each time two monomers join
Question 3Hard6 marks
Compare addition polymerisation with condensation polymerisation. In your answer refer to the monomers, the products and the repeating units.[6]
Show the answer and mark scheme
Answer: See indicative content.
addition: the monomers contain a C=C double bond; condensation: each monomer has two functional groups
addition: usually one type of monomer, e.g. ethene; condensation: often two different monomers, e.g. a diol and a dicarboxylic acid (or one monomer with two different groups, e.g. amino acids)
addition: the double bond opens up and the monomers join; condensation: the functional groups react to form links (e.g. ester links)
addition: the polymer is the only product; condensation: a small molecule such as water is also produced
addition: the repeating unit has the same atoms as the monomer; condensation: the repeating unit has fewer atoms than the monomers because water is lost
examples: poly(ethene) and poly(propene) are addition polymers; polyesters and polypeptides (proteins) are condensation polymers
Marked with levels of response: the full level descriptors are in the app.