27 Amines, amino acids, and polymers Flashcards

1
Q

What is optical isomerism? (1 mark)

A

When the mirror images of molecules are non-superimposable.

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2
Q

What is a chiral carbon atom? (1 mark)

A

A carbon atom that has four different groups attached to it.

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3
Q

What are two compounds that are optical isomers of each other called? (1 mark)

A

Enantiomers

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4
Q

What is a 50/50 mixture of two enantiomers called? (1 mark)

A

A racemic mixture/ racemate

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5
Q

What is the main difference between optical isomers? (1 mark)

A

They affect plane polarised light differently.

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6
Q

Why does a racemate have no effect on the plane of light? (1 mark)

A

Each enantiomer rotates the plane polarised light by the same amount, but in the opposite direction.
This means the effects of the enantiomers cancel out.

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7
Q

What is the functional group of an amine? (1 mark)

A

NH2

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8
Q

What are amines derived from? (1 mark)

A

Ammonia

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9
Q

What are the two types of amines? (2 marks)

A

Aliphatic amine
Aromatic amine

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10
Q

What is an aliphatic amine? (1 mark)

A

The nitrogen atom is attached to at least one carbon chain.

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11
Q

What is an aromatic amine? (1 mark)

A

The nitrogen atom is attached to an aromatic ring.

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12
Q

What is a primary amine? (1 mark)

A

The nitrogen is attached to one a carbon chain.

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13
Q

What is a secondary amine? (2 marks)

A

The nitrogen is attached to 2 carbon chains.

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14
Q

What is the tertiary amine? (3 marks)

A

The nitrogen is attached to 3 carbon chains.

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15
Q

How do you name secondary/tertiary amines? (2 marks)

A

Call it an N-substituted derivative of the larger group.

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16
Q

What is serotonin? (2 marks)

A

An amine that acts as a neurotransmitter, controlling sleep, appetite, memory and many other things.

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17
Q

What is pseudoephedrin? (2 marks)

A

An amine that is used in decongestion medications.

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18
Q

Why do amines act as bases in chemical reactions? (1 mark)

A

They have a lone pair of electrons on the N that can accept a proton.

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19
Q

What is the name of an amine ion? (1 mark)

A

ammonium ion

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20
Q

How do amines react with acids? (1 mark)

A

Amines neutralise amines to make salts.

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21
Q

How do you prepare a primary aliphatic amine, using a haloalkane? (3 marks)

A

Ammonia + haloalkane–> Ammonium salt
Ammonium salt + alkali (aq) –> amine

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22
Q

What are the conditions required to prepare an aliphatic amine from a haloalkane, and explain why they are used? (4 marks)

A

ethanol- prevents substitution of haloalkane by water to produce alcohols
excess ammonia- reduces further substitution

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23
Q

How do you prepare a secondary/tertiary amine, using a haloalkane? (2 marks)

A

Prepare a primary amine
Primary amine + haloalkane –> ammonium salt
ammonium salt + alkali (aq) –> amine

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24
Q

How do you prepare an aromatic amine? (3 marks)

A

Reduction of nitrobenzene- heated under reflux with tin and HCl
Add excess NaOH

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25
Q

What functional groups do amino acids contain? (2 marks)

A

NH2
COOH

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26
Q

How do amino acids react with acids? (2 marks)

A

The amine group is basic, and react with acids to make salts.

27
Q

How do amino acids react with aqueous alkalis? (2 marks)

A

The carboxylic acid group reacts with the alkali to form a salt.

28
Q

How do amino acids react with alcohols? (2 marks)

A

The carboxylic acid group reacts with the alcohol to form an ester.

29
Q

What are the conditions required to form an ester from an amino acid? (2 marks)

A

heating
alcohol
concentrated sulfuric acid

30
Q

What are amides the products of? (2 marks)

A

acyl chloride + ammonia/amines

31
Q

What is the functional group of an amide? (2 marks)

A

Carbonyl group bonded to a nitrogen.
CON or CONH or CONH2

32
Q

What is a primary amide? (1 mark)

A

The nitrogen is attached to one a carbon chain.

33
Q

What is a secondary amide? (1 mark)

A

The nitrogen is attached to two carbon chains.

34
Q

What is a tertiary amide? (1 mark)

A

The nitrogen is attached to three carbon chains.

35
Q

Do amines have hydrogen bonds between molecules, why/why not? (2 marks)

A

Yes, they contain N-H bonds.

36
Q

Explain why a tertiary amine has a much lower boiling point than primary and secondary amines of similar Mr. (2 marks)

A

They have no hydrogen atoms directly attached to the nitrogen, so hydrogen bonding cannot happen between molecules.

37
Q

What is trend in solubility of amines as their caron chains get longer, why? (2 marks)

A

Less soluble as carbon chains increase in length,
because they force their way between water molecules, breaking the hydrogen bonds between water molecules and nitrogens in amines.

38
Q

Draw the mechanism of the production of an amine from a haloalkane. (6 marks)

A

Step 1:
1. Curly arrow from ammonia to carbon bonded to halogen in haloalkane
2. Curly arrow from bond C-halogen bond to halogen
Step 2:
3. Ammonia is now bonded to carbon chain from haloalkane in intermediate
4. Curly arrow from N-H bond to N+
5. Curly arrow from released another ammonia molecule to hydrogen
6. Correct product

39
Q

Describe how an amine is produced by the reduction of a nitrile compound, in a lab, include the reagents and conditions. (4 marks)

A
  1. haloalkane + KCN –> nitrile compound
  2. nitrile compound + 4[H] –> amine
    LiAlH4 in ethoxyethane
40
Q

Describe how an amine is produced by the reduction of a nitrile compound, in industry, include the reagents and conditions. (4 marks)

A
  1. haloalkane + KCN –> nitrile compound
  2. nitrile compound + 2H2 –> amine
    Ni catalyst + heat
41
Q

Why is phenylamine a weaker base than ammonia? (2 marks)

A

The lone pair of electrons on the nitrogen of the phenylamine is delocalised into the benzene ring,
making it less available to combine with hydrogen ions.

42
Q

What zwitterton does an amino acid exist as at a low pH? (1 mark)

A

The NH2 group is protonated to NH3+

43
Q

What zwitterton does an amino acid exist as at a neutral pH? (2 marks)

A

The NH2 group is protonated to NH3+
The COOH group is unprotonated to COO-

44
Q

What zwitterton does an amino acid exist as at a high pH? (1 mark)

A

The COOH group is unprotonated to COO-

45
Q

What is condensation polymerisation? (1 mark)

A

The joining of monomers with the loss of a small molecule (usually H20/HCl)

46
Q

What links the monomers in polyesters? (1 mark)

A

Ester linkages

47
Q

What functional groups must a monomer contain to turn a polyester by condensation polymerisation? (2 marks)

A

COOH and OH

48
Q

A polyester is made of two monomers, what functional groups must each monomer contain? (2 marks)

A

One contains 2 COOH groups
One contains 2 OH groups

49
Q

What is lactic acid derived from? (1 mark)

A

Maize

50
Q

Give an example of a polyester formed from one monomer. (1 mark)

A

Poly (lactic acid)
Poly (glycolic acid)

51
Q

Give an example of a polyester formed from two monomers. (1 mark)

A

Treylene (PET)

52
Q

What links the monomers in polyamides? (1 mark)

A

Amide linkages

53
Q

What functional groups must a monomer contain to turn a polyamide by condensation polymerisation? (2 marks)

A

COOH/COCl and NH2

54
Q

A polyamide is made of two monomers, what functional groups must each monomer contain? (2 marks)

A

One contains 2 COOH/COCl groups
One contains 2 NH2 groups

55
Q

What type of polymer do amino acids form, why? (2 marks)

A

Polyamide
Contain a COOH and a NH2

56
Q

How are condensation polymers hydrolysed? (1 mark)

A

Using an aqueous, hot acid/alkali

57
Q

What is formed when a polyester undergoes acid hydrolysis? (2 marks)

A

Alcohol
Carboxylic acid

58
Q

What is formed when a polyester undergoes alkali hydrolysis? (2 marks)

A

Alcohol
A carboxylic salt

59
Q

What is formed when a polyamide undergoes acid hydrolysis? (2 marks)

A

Carboxylic acid
Ammonium ion

60
Q

What is formed when a polyamide undergoes alkali hydrolysis? (2 marks)

A

Amine
A carboxylic salt

61
Q

Why are condensation polymers biodegradable? (2 marks)

A

Because contain C-O or C-N polar bonds in the main chain, which are susceptible to chemical attack.

62
Q

What are the strongest forces between polymer chains in addition polymers? (1 mark)

A

Induced dipole-dipole interactions

63
Q

What are the strongest forces between polymer chains in polyesters? (1 mark)

A

Permanent dipole-dipole interactions

64
Q

What are the strongest forces between polymer chains in polyamides? (1 mark)

A

Hydrogen bonds