CIE Mar 2016 v2 Paper 4 Q9

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PMT (a) (i) Name an example of a synthetic polyester and a synthetic polyamide. 18 polyesterpolyamide[1] (ii) Polyesters and polyamides are formed by condensation reactions. Name a molecule which is commonly eliminated in such reactions.[1] (b) (i) The table shows the repeat units of a number of polymers. Place a tick () against the ones which are biodegradable. biodegradable polymer repeat unit CH3 CH3O N H N H (ii) Draw the structures of two monomers used to form polymer B.UCLES 2016 9701/42/F/M/16 [2] [2]<br />
 (c) A section of polypeptide was hydrolysed and the following amino acids identified. 19 PMT amino acid formula T U V CH3CH(NH2)CO2H C6H5CH2CH(NH2)CO2H H2N(CH2)4CH(NH2)CO2H (i) Which of the amino acids T, U or V has the highest pH in aqueous solution? Explain why. amino acid[1] (ii) State how many different dipeptides could be formed from a reaction mixture consisting of amino acids T and U.[1] (iii) Polypeptides contain a high proportion of carbon and hydrogen in their structures, yet many are soluble in water. By referring to the structure of a polypeptide, explain why.[2] [Total: 10]UCLES 2016 9701/42/F/M/16 [Turn over<br />

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