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A level Chemistry > Chapter 27 - Amines, Amino Acids, Polymers > Flashcards

Chapter 27 - Amines, Amino Acids, Polymers Flashcards

1
Q

1° amines?

A

have one alkyl chain attached to the N (so 2H too)

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2
Q

2° amines?

A

have 2 alkyl chains attached to the N (so 1 H)

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3
Q

3° amines?

A

have 3 alkyl chains (so no H) attached to the N

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4
Q

how to name short primary amines?

A
  • alkyl prefix

- then add ending amine

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5
Q

how to name short secondary and tertiary amines?

A
  • di/tri alkyl ➡ how many alkyl groups attached to the N

- amine ending

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6
Q

how to name longer amines?

A
  • amino prefix

- name the rest of the chain as usual

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7
Q

benzene and an amine gr is?

A

phenylamine

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8
Q

pH of amines?

A
  • 9/10

- weak alkaline

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9
Q

amines solubility?

A
  • can bond w water

- weak IDFs between molecules, easy to overcome

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10
Q

as C chain length ⬆, the solubility of the amine ?

A

solubility ⬇ as C chain length ⬆ as IDFs increase so the organic molecule stays bonded together

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11
Q

ammonia + water reversible ➡

A

NH4+ + OH-

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12
Q

formation of ammonia?

A

N2(g) + 3H2 (g) RA 2NH3(g)

  • the haber process
  • Fe(s) catalyst
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13
Q

ammonia acting a base equation?

A

NH3 + H2O ➡ NH4+

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14
Q

When ammonia acts as a base?

A

ammonium salt formed

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15
Q

structure of ammonia?

A

pyramidal, 107°

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16
Q

structure of methylamine?

A

pyramidal, 107°around N

109.5°, tetrahedral around C

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17
Q

Amines also react with acids to ?

A

form ammonium salts

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18
Q

amine groups mean?

A

H bonds between molecules

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19
Q

phenylamine?

A

has higher e- density than benzene bc of NH2

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20
Q

neutralisation?

A

if there r 2 N, then 2 protons (H+) are added

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21
Q

aliphatic =

A

chains and rings but NOT benzene rings

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22
Q

aromatic =

A

benzene ring

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23
Q

preparation of 1° aliphatic amines?

A

R: DRY (to stop alcohol formation) NH3 in excess (to prevent further subs)
C: in ethanol, reflux

CH3Cl + 2NH3 ➡ CH3NH2 + NH4Cl

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24
Q

preparation of 1° aliphatic amines: why is ammonia left w + charge?

A

one e- from lone pair went to C in bond

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25
Q

how do we prepare aromatic amines?

A

reduction (addition of H) of nitrobenzene

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26
Q

preparation of aromatic amine 1?

A

R: Sn (tin) and conc HCl
C: reflux
Eq: nitrobenzene + 6[H] ➡ phenylamine + 2H2O

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27
Q

preparation of aromatic amine 2?

A

phenylamine + HCl ➡phenylammonium chloride salt (C6H5NH3Cl)
Reverse the reaction:
C6H5NH3Cl + NaOH ➡ phenylamine + NaCl + H2O

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28
Q

Further nucleophilic substitution: preparation of a secondary amine?

A

CH3Cl + 2NH3 ➡ CH3NH3 + NH4Cl

ammonia is NOT in excess

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29
Q

Further nucleophilic substitution: preparation of a tertiary amine?

A

react a secondary amine with CH3Cl

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30
Q

why can’t be use ammonia and benzene to make phenylamine?

A
  • NH3 = nucleophile
  • Benzene takes part in electrophilic reactions
  • phenyl is e- dense, repels nucleophiles
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31
Q

NS to form an amine always also forms?

A

an ammonium salt

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32
Q

v

A

vv

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33
Q

v

A

v

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34
Q

how many optical isomers does a molecule with 2 chiral carbon atoms have?

A

4

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35
Q

features that allow a molecule to be described as an AA?

A

amine group AND CA group

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36
Q

in an alpha amino acid?

A

NH2 and COOH bonded to the same C

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37
Q

when an AA is in alkaline conditions?

A

both COOH lose their H+ and react w the metal ion e.g. COO-Na+

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38
Q

when an AA is in acidic conditions?

A

NH2 gains a H+ to become N+H3 and reacts w negative ion

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39
Q

ethanoic acid vs glycine: solubility and pH

A

Ethanoic acid: ph4, red, soluble as 1 layer
gly: neutral - 5/6 (fewer H+) - dissolved
NH2 and COOH almost cancel out

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40
Q

ethanoic acid vs glycine: + Mg

A

Ethanoic acid: squeaky pop, vigorous reaction

gly: green quickly, little fizzing, no squeaky pop

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41
Q

ethanoic acid vs glycine: indicator and NaOH

A

Ethanoic acid: low pH - more H+

gly: more alkaline, higher pH - less H+

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42
Q

ethanoic acid vs glycine: + Na2CO3

A

Ethanoic acid: fizzing, limewater bubbling

gly: blue, no fizzing

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43
Q

ethanoic acid vs glycine: ethanol and conc H2S04?

A

Ethanoic acid: fizzing, strong smell

gly: milder smell, fewer COOH as internal ionisation

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44
Q

AA: phenol FG is ?

A

acidic

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45
Q

AA: whatever O does in an organic compound,

A

sulfur does too

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46
Q

NH2 is?

A

the amine group

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47
Q

amino acids reactions?

A
  • nucleophilic

* neutralisation

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48
Q

Amine neutralisation reaction

A

CH3NH2 + HCl ➡ CH3NH3+Cl-

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49
Q

amine nucleophilic substitution reaction?

A

CH3Cl + 2CH3NH2 ➡ (CH3)2NH + CH3HN3Cl

50
Q

amide bond?

A

C=ONH

51
Q

AA in acidic conditions?

A

NH2 ➡NH3+

reacts w basic part which becomes protonated

52
Q

AA n alkaline conditions?

A

COOH loses H+ which reacts w OH- to form H2O

COO-

53
Q

Remember ALL

A

acidic and all basic groups

54
Q

phenol in alkaline conditions ?

A

loses H off OH, leaving O-

55
Q

what gives rise to optical isomerism?

A

• The C atom in the centre has 4 different groups of atoms attached - this is a chiral carbon atom

56
Q

CCA: CH2 and CH3

A

are different groups!

57
Q

CCA: if the C only has 3 bonds (a double bond)

A

can’t be a CCA

58
Q

CCA: non superimposable

A
  • optical isomers are non superimposable mirror images bc they have different spatial arrangements
  • these are optical isomers
59
Q

the non-superimposable mirror images are called…

A

optical isomers or enantiomers. This type of molecule is said to be chiral.

60
Q

what is a chiral C atom?

A
  • C surrounded by 4 diff groups
  • sometimes >1 in a molecule
  • denoted by an *
61
Q

what is the rule for determining whether an AA is classified as a D or L optical isomer?

A

if the AA rotates plane polarised light to the right it is D/+ (L/ - if left)

62
Q

what type of AA are used in the human body?

A

always L/- isomer. Carbs are all D/+ isomer in the body.

63
Q

similarities between optical isomers?

A
  • very similar chemical and physical properties

* same structural and molecular formula (they are stereoisomers)

64
Q

differences between optical isomers?

A
  • they rotate plane polarised light in opposite directions
  • they react differently w other chiral molecules
  • different arrangement of atoms in space
65
Q

optical isomerism is a type of?

A

stereoisomerism

66
Q

amide FG?

A

C=ONH

67
Q

When do amides occur?

A

when u react an acyl chloride w ammonia and amines

68
Q

What is a condensation reaction?

A

joining 2 molecules together by removing a molecule of water

69
Q

what are peptides?

A
  • amides

* that form when 2 AAs react in a condensation reaction

70
Q

dipeptides?

A

form when 2 amino acids react together

71
Q

there can be ? in peptides?

A

chiral carbon atoms

72
Q

peptide bond?

A

only used when joining 2 AA (an amide bond)

73
Q

when the question asks for 2 (di)peptides?

A

just rearrange the order of the AA in the polyamide/ peptide
e.g. Cys-Ser and Ser-Cys

74
Q

when naming a peptide…

A

just write the seq of AAs

75
Q

⭐peptides

A

look out for rings, see if more condensation can happen. Examiner will often get u to form a ring and deduce the structure of the ring

76
Q

hydrolysis of a peptide,

A

if acid/ base specified then include the ion in the products

77
Q

⭐when hydrolysing peptides w an acid catalyst,

A

protonate ALL amine groups (even ones on the end!)

78
Q

⭐when hydrolysing peptides w an alkali catalyst?

A

acid groups are deprotonated (lose H+) - be careful to check r group for acid
remember that phenol is an acid

79
Q

alcohols are ?

A

neutral, OH stays as it is

80
Q

which AA is optically inactive?

A

r group = H

81
Q

when talking about the solubility of a peptide?

A
  • talk about H bonds w water (NH2/COOH)

* talk about induced dipole forces - energy needed to break

82
Q

how to determine if a peptide is basic/neutral/alkaline?

A
  • how many acidic groups
  • vs how many basic groups
  • if there’s more basic, H+ would be accepted and alkaline pH
83
Q

when can you form a polyester?

A
  • when have dioic acid/ diol

* when have a molecule w CA and alcohol

84
Q

suggest what makes a polymer biodegradable?

A
  • ester bond can be hydrolysed by water in the envir

* C=O absorbs radiation

85
Q

condensation reactions remove?

A

H2O/HCl

86
Q

condensation polymerisation is just ? multiple times

A

esterification

87
Q

condensation polymerisation put FG

A

at the end of the molecule

88
Q

polyester - monomers?

A
  1. 1 monomer w alcohol and CA FG (2 of these used)

2. 2 monomers - 1 diol and 1 dioic acid

89
Q

polyesters will have

A

more than 1 repeat unit

90
Q

condensation polymerisation remember to put ? in equation

A

water

91
Q

what is a diamine?

A

2 NH2 groups

92
Q

how can a polyamide be formed?

A
  1. diamine and dicarboxylic acid

2. AAs

93
Q

condensation polymerisation: CA loses

A

OH

94
Q

condensation polymerisation: remember

A

lines either side of the polymer to show it repeats

95
Q

condensation polymerisation: when benzene is involved, be careful to

A

keep the positions right

96
Q

condensation polymerisation: benzene’s effect on the polymer

A
  • benzene is planar, 120 degrees
  • makes chain flat
  • so pack closely together
  • dense, strong IM and ⬆ MP
97
Q

CP vs AP - biodegradable?

A
  • polyalkenes do not biodegrade

* CP - polyesters and polyamides can be hydrolysed by H2O so are biodegradable

98
Q

acid hydrolysis of polyesters?

A

• monomers reformed

99
Q

base hydrolysis of polyesters?

A
  • NaOH ➡ NaO and H
  • NaO to C=O to make Na+ -OC=O
  • H to O
100
Q

base hydrolysis - need ? mol of base when a monomr has 2 CA groups?

A

2

101
Q

acid hydrolysis of polyamides?

A

• NH2 protonated in acid to become NH3

102
Q

Base hydrolysis of polyamides?

A

NaO to C=O and H to NH

103
Q

when is an amide formed and when is a polyamide formed ?

A

amide: CA + Amine ➡ amide + water
polyamide: diol + dioic acid/ 2 AA
FOR POLYAMIDE IT HAS TO BE DI

104
Q

how to tell if it’s an addition or condensation polymer?

A

Addition: backbone chain that only contains C
condensation: chain will contain ester/amide bonds - break these to get monomers

105
Q

⭐phenol does NOT

A

form ester w CAs

106
Q

when asked about a polymer impurity>

A

think abt rings

107
Q

single headed arrow shows movement of?

A

1 electron. Used when radicals are formed

108
Q

where do the numbers in the name of nylon come from?

A

the no. of Cs

first amine Cs then CA Cs

109
Q

why can a polymer undergo acid hydrolysis but is not biodegrdable?

A

the backbone doesn’t break, only sidechain does so polymer not broken down

110
Q

base hydrolysis n

A

2n-1 of the base

111
Q

why do addition polymers not degrade easily?

A
  • alkanes

* can’t be hydrolysed

112
Q

properties of polymers involving benzene rings?

A
  • flat molecules
  • pi bond in C=O and 120 trig planar
  • chains pack closely
  • strong IMFs (H bonds bc amide group)
  • dense structure
113
Q

Ap: no. of types of monomer ?

A

1, alkenes

114
Q

AP: atom economy?

A

100% - one product

115
Q

AP: type of reaction?

A

electrophilic addition

116
Q

AP: uses ?

A
  • PVC
  • Plastics
  • Teflon
117
Q

AP: biodegradability?

A

no - alkanes = unreactive

118
Q

CP: no of type of monomer ?

A
  • diamines and dioic acid
  • dioic acid and diol
  • AA
  • hydroxy-oic acid
119
Q

CP: atom economy?

A

<100% - water/ HCl formed

120
Q

CP: type of reaction?

A

condensation

121
Q

CP: uses?

A
  • making polyester and polyamides

* often used as fibres and ester

122
Q

CP: biodegradability?

A

yes amide bond can be hydrolysed using water from environment

A level Chemistry (39 decks)

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