Synthetic Polymers
5 marks · EasyPoly(chloroethene), also known as PVC, is a common synthetic polymer.
State the name of the monomer used to produce poly(chloroethene).
Describe what occurs to the double bond during addition polymerisation of this monomer.
Deduce and draw the displayed formula of the repeat unit of poly(chloroethene), showing all atoms with their bonds clearly.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) chloroethene or vinyl chloride · must show Correct name, accept either
(b) The double bond opens up, so each carbon forms a new single bond with the next monomer, extending the chain; no other products form. · must show double bond breaks, single bonds form between carbons of different molecules, addition polymerisation, no other product
(c) [—CH2—CHCl—] · must show Two carbon backbone, one hydrogen and one chlorine on one carbon, two hydrogens on the other, all bonds shown
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly states 'chloroethene' or 'vinyl chloride' as the monomer.
B2 (b) · 1 mark · Describes opening/breaking of the double bond in the monomer.
B3 (b) · 1 mark · Mentions that single bonds are formed with adjacent units, and that no other products are formed.
B4 (c) · 1 mark · Correct structure of repeat unit with all atoms (CH2—CHCl) and correct bond arrangement.
B5 (c) · 1 mark · Shows continuation bonds, as appropriate for repeat units.
Worked solution
a) The monomer is called chloroethene (or vinyl chloride).
b) During addition polymerisation, the double bond between the two carbon atoms in each monomer breaks open. This allows each carbon atom to bond to a neighbouring monomer. No other products are formed as all atoms from the monomer are included in the polymer chain.
c) The repeat unit of poly(chloroethene) can be drawn as:
or condensed as [—CH2—CHCl—]