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8/10/2019 HOMEWORK Polymers and Synthesis
1/21
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
8/10/2019 HOMEWORK Polymers and Synthesis
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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Paddington Academy 2
8/10/2019 HOMEWORK Polymers and Synthesis
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.
$2&
$+otal mars&
Paddington Academy 3
8/10/2019 HOMEWORK Polymers and Synthesis
4/21
2. /mino acids can act as monomers in the formation of polypeptides and proteins. +hestructures below show three amino acids, glycine, phenylalanine and proline.
H2
N C C O O H
H
H
H2
N C C O O H
H
C H 2
C H0 1
CH N
H C2
CH 2
C H 2
C O O H
H
g l y c i n e p r o l i n ep h e n y l a l a n i n e
lycine, phenylalanine and proline can react together to form a mi#ture of tripeptides.
i! *raw the structure of the tripeptide formed in the order glycine, phenylalanineand proline.
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ii! How many different tripetides could have been formed containing glycine,phenylalanine and proline
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iii! +he mi#ture of tripeptides can be analysed by using gas chromatography,coupled with mass spectrometry.
'ummarise how each method contributes to the analysis.
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$+otal mars&
Paddington Academy 4
8/10/2019 HOMEWORK Polymers and Synthesis
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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$2&
ii! +he three organic products all belong to the same class of compound. 'tate thegeneral name for this class of organic compound.
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iii! *raw the structure of one of the organic products from the hydrolysis of A usingthe reagent you have given in a!i! above.
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iv! "#plain what is meant by the term hydrolysis. 4se this reaction to illustrate youranswer.
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$+otal mars&
Paddington Academy 5
8/10/2019 HOMEWORK Polymers and Synthesis
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 $%&
$+otal mars&
Paddington Academy 6
8/10/2019 HOMEWORK Polymers and Synthesis
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.
$%&
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.
$3&
$+otal 9 mars&
Paddington Academy 7
8/10/2019 HOMEWORK Polymers and Synthesis
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&
Paddington Academy 8
8/10/2019 HOMEWORK Polymers and Synthesis
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&
Paddington Academy 9
8/10/2019 HOMEWORK Polymers and Synthesis
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&
Paddington Academy 10
8/10/2019 HOMEWORK Polymers and Synthesis
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.
$%&
b! Cinnamaldehyde shows cis-trans isomerism.
i! "#plain how cis-trans isomerism arises in cinnamaldehyde.
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ii! 'tate and e#plain whether cinnamaldehyde is a cis or a trans isomer.
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iii! *raw a seletal or displayed formula to show the structure of the other cis-trans isomer of cinnamaldehyde.
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$+otal 1 mars&
Paddington Academy 11
8/10/2019 HOMEWORK Polymers and Synthesis
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
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