Making a polyester

2 marks · Easy

A polyester is made from 7 molecules of hexane-1,6-dioic acid reacting completely with 7 molecules of ethan-1,2-diol. How many ester links are formed in the resulting polyester molecule?

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13 (±0)

Also accept: thirteen

Common mistakes: 14; 7

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Marking points

M1 · 1 mark · Realises there will be 2n-1 ester links in the polymer, with n = 7.

A1 · 1 mark · Calculates 2×7-1 = 13 ester links.

Worked solution

13 ester links are formed when 7 molecules of each monomer react completely.