HOMEWORK Polymers and Synthesis

8/10/2019 HOMEWORK Polymers and Synthesis

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A2 LEVEL CHEMISTRY

4.2.1 AMINO ACIDS AND CHIRALITY

4.2.2 POLYESTERS AND POLYAMIDS

4.2.3 SYNTHESIS

ASSESSED HOMEWORK

Answer all questions

Max 107 marks

Name ..

Mark ../107 ....% Grade

Paddington Academy 1


2/21

1. Compound A, shown below, is an amino acid that is being used in the development ofa new anti-inflammatory drug.

H N2

C H

c o m p o u n d

3

A

H H O

O HH

CC C

a! i! "#plain why this molecule is described as an amino acid.

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ii! 'tate the general formula of an -amino acid.

"#plain whether or not compound A fits this general formula.

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b! Compound A e#ists as a (witterion in a)ueous solution.

i! *raw the structure of this (witterion.

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ii! 'how how the structure of the (witterion would change if the solution wasacidified with dilute hydrochloric acid.

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3/21

c! +he anti-inflammatory drug is made by combining compound A with compoundB, shown below. represents a side chain.

c o m p o u n d B

H O

O HH

CC

'how the structure of the anti-inflammatory drug formed from compound A andcompound B.

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$+otal mars&



4/21

2. /mino acids can act as monomers in the formation of polypeptides and proteins. +hestructures below show three amino acids, glycine, phenylalanine and proline.

H2

N C C O O H

H

H

H2

N C C O O H

H

C H 2

C H0 1

CH N

H C2

CH 2

C H 2

C O O H

H

g l y c i n e p r o l i n ep h e n y l a l a n i n e

lycine, phenylalanine and proline can react together to form a mi#ture of tripeptides.

i! *raw the structure of the tripeptide formed in the order glycine, phenylalanineand proline.

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ii! How many different tripetides could have been formed containing glycine,phenylalanine and proline

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iii! +he mi#ture of tripeptides can be analysed by using gas chromatography,coupled with mass spectrometry.

'ummarise how each method contributes to the analysis.

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5/21

3. Compound A is currently being tested as a possible anti-allergic drug.

C C NN C C N C C

C H CH

C H

O H2 2

2

HH

H

H H

H OO

C

O O H

OH H

c o m p o u n d A

Compound A can be hydrolysed to form three organic products.

i! Name a suitable reagent and conditions for the hydrolysis of compound A.

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ii! +he three organic products all belong to the same class of compound. 'tate thegeneral name for this class of organic compound.

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iii! *raw the structure of one of the organic products from the hydrolysis of A usingthe reagent you have given in a!i! above.

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iv! "#plain what is meant by the term hydrolysis. 4se this reaction to illustrate youranswer.

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6/21

4. 5n this )uestion, one mar is available for the )uality of the use and organisation ofscientific terms.

5n all living organisms a large variety of polypeptides and proteins are formed naturally

from -amino acids.

'tate the general formula of an 6-amino acid and use it to describe how amino acidscan be combined to give a variety of polypeptides and proteins.

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7uality of 8ritten Communication $%&

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7/21

5. 'ome of the 6-amino acids found in human sweat are shown in the table below.

-amino acid R group

glycine H

leucine CH2CHCH3!2

isoleucine CHCH3!CH2CH3

alanine CH3

valine CHCH3!2

lysine CH2!9NH2

glutamic acid CH2!2COOH

i! 'tate the general formula of an 6-amino acid.

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ii! +here are four stereoisomers of isoleucine.

One of the stereoisomers is shown below.

C H2

C H3

N H2

C

C

H

H

H3

C

H O O C

*raw 3* diagrams for the other threestereoisomers of isoleucine.

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$+otal 9 mars&



8/21

6. lutamic acid and glycine are both -amino acids that occur widely in living organisms.

+heir structures are shown below.

H N2 C

H

C O O H H N2 C

H

H

C O O H

C H

C H

C O O H

2

2

g l u t a m i c a c i d g l y c i n e

a! i! 'tate the general formula for an -amino acid.

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ii! "#plain how glutamic acid and glycine both fit the general formula given inpart i!

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b! /mino acids react with both acids and alalis.

*raw structures below to show how the glutamic acid molecule is changed in thepresence of e#cess acid and alali.

H N2 C

H

C O O H

C H

C H

C O O H

2

2

g l u t a m i c a c i d

e # c e s sH C a ) !l

e # c e s sN a O H a ) !

$1&



9/21

c! 5n this )uestion, one mar is available for the )uality of use and organisation ofscientific terms.

lutamic acid e#ists as two optical isomers, but glycine does not.

"#plain what structural feature causes optical isomerism in organic molecules.

5nclude appropriate diagrams and use these two amino acids to illustrate youranswer.

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7uality of 8ritten Communication $%&

$+otal %0 mars&



10/21

7. :ut-2-enal, CH3CH;CHCHO, is a pale yellow, flammable li)uid with an irritating odour.

:ut-2-enal e#ists as two stereoisomers.

*raw seletal formulae to show the structure of the two stereoisomers of but-2-enal.

$+otal 2 mars&



11/21

8. Cinnamaldehyde is the compound that gives cinnamon its distinctive flavour.

H

H

H

CC

CO

c i n n a m a l d e h y d e

a! *raw the seletal formula of cinnamaldehyde.

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b! Cinnamaldehyde shows cis-trans isomerism.

i! "#plain how cis-trans isomerism arises in cinnamaldehyde.

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ii! 'tate and e#plain whether cinnamaldehyde is a cis or a trans isomer.

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iii! *raw a seletal or displayed formula to show the structure of the other cis-trans isomer of cinnamaldehyde.

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$+otal 1 mars&



12/21

9. 'ynthetic polyamides, such as nylon, contain the same lin as polypeptides. Nylon isthe general name for a family of polyamides.

/ short section of a nylon polymer is shown below.

C

O

C

O

N

H

C H2

!

HOMEWORK Polymers and Synthesis

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