Section 5 - Isomerism and Carbonyl Compounds Flashcards

1
Q

What type of isomerism is optical isomerism?

A

Stereoisomerism.

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2
Q

What is a chiral/asymmetric carbon atom?

A

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

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3
Q

What are optical isomers/enantiomers?

A

Molecules which have different spatial arrangements of groups around the chiral carbon - they are non-superimposable mirror images.

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4
Q

What kind of light only vibrates in one direction?

A

Plane-polarised light.

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5
Q

What does optically active mean?

A

The isomer rotates plane-polarised light.

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6
Q

How can you differentiate enantiomers?

A

One will rotate plane-polarised light clockwise and the other anti-clockwise.

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7
Q

What is a racemate/racemic mixture?

A

A mixture which contains equal quantities of each enantiomer of an optically active compound.

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8
Q

Why don’t racemates show any optical activity?

A

The two enantiomers cancel each other’s light rotating effect.

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9
Q

Which type of reaction often produces racemates?

A

Reactions involving planar bonds, eg, C=C or C=O bonds. Often aldehydes or unsymmetrical ketones.

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10
Q

Why is potassium cyanide dangerous?

A

It is an irritant and dangerous if inhaled or ingested.

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11
Q

Why is hydrogen cyanide dangerous?

A

It is a highly toxic gas.

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12
Q

What is a carbonyl group?

A

C=O

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13
Q

What is the differences between aldehydes and ketones.

A

In an aldehyde the carbonyl is at the end of the chain but in a ketone, it is in the middle.

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14
Q

What are aldehydes oxidised into?

A

Carboxylic acids.

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15
Q

What are ketones oxidised into?

A

Can’t be oxidised.

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16
Q

What type of reaction occurs when you use Tollen’s reagent or Fehling’s solution?

A

Redox.

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17
Q

What is Tollen’s reagent?

A

Solution of silver nitrate dissolved in aqueous ammonia.

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18
Q

What reaction occurs when Tollen’s reagent is heated in a test tube with an aldehyde?

A

The Ag+ ions are reduced to Ag atoms.

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19
Q

What colour change occurs when Tollen’s reagent is heated in a test tube with an aldehyde?

A

Colourless solution turns into a silver mirror.

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20
Q

What reaction occurs when Tollen’s reagent is heated in a test tube with a ketone?

A

No reaction - can’t be oxidised.

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21
Q

How strong are carboxylic acids?

A

Weak.

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22
Q

What reducing agent can you use to reverse the oxidation of alcohols?

A

NaBH4 dissolved in water with methanol.

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23
Q

What do you use in equations to symbolise a reducing agent?

A

[H].

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24
Q

What reaction occurs when Fehling’s solution is heated in a test tube with an aldehyde?

A

The copper(II) ions are reduced to a copper(I) oxide.

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25
Q

What colour change occurs when Fehling’s solution is heated in a test tube with an aldehyde?

A

The blue solution turns to a brick-red precipitate.

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26
Q

What reaction occurs when Fehling’s solution is heated in a test tube with a ketone?

A

No reaction occurs.

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27
Q

What is Fehling’s solution?

A

A blue solution of copper(II) ions dissolved in sodium hydroxide.

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28
Q

What is the mechanism for potassium cyanide reacting with carbonyls?

A

Nucleophilic addition.

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29
Q

What products are formed when carboxylic acids react with carbonates?

A

A salt, carbon dioxide and water.

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30
Q

What products are formed when carboxylic acids react with alcohols?

A

An ester and water.

31
Q

What are the conditions for the reaction of carboxylic acid with alcohol?

A
  • Heat - Reflux -Strong acid catalyst
32
Q

What are the reactants of an esterification reaction?

A

Carboxylic acid and alcohol.

33
Q

In naming esters, which reactants form each part of the ester?

A

Alcohol - propyl group Acid -oate

34
Q

Give 4 uses of esters:

A
  • Food flavouring - Perfumes - Solvents - Plasticisers
35
Q

Give 3 properties of esters:

A
  • Sweet smell - Polar - Low bpt
36
Q

What product is formed when esters are hydrolysed?

A

Alcohols.

37
Q

What is used to speed up hydrolysis reactions?

A

Acids or alkalis.

38
Q

What are the products of an acid hydrolysis reaction between ethyl ethanoate and water with an acid catalyst?

A

Ethanoic acid and Ethanol.

39
Q

What are the products of a base hydrolysis reaction between ethyl ethanoate and OH-?

A

Ethanoate and Ethanol.

40
Q

What are fatty acids?

A

Long chain carboxylic acids.

41
Q

What do fatty acids combine with to make esters?

A

Glycerol.

42
Q

What are the properties of animal fats?

A
  • mainly saturated - can pack tightly - high VdWs - high mpts - solid @ room temp
43
Q

What are the properties of vegetable oils?

A
  • mainly unsaturated - can’t pack tightly - weak VdWs - low mpts - liquid @ room temp
44
Q

How do you hydrolyse vegetable oils and animal fats?

A

Heat them with sodium hydroxide.

45
Q

What salt is formed when vegetable oil or animal fat is hydrolysed with sodium hydroxide?

A

Glycerol, Fatty Acids and Sodium Salt - SOAP!

46
Q

What is biodiesel a mixture of?

A

Methyl esters of fatty acids.

47
Q

What do you react to get biodiesel? (reactants and products)

A

Ester + Alcohol —–> Glycerol and Methyl Ester

48
Q

What is the catalyst for the reaction to make biodiesel?

A

KOH.

49
Q

What can acyl chlorides react with?

A
  • Water - Alcohols - Ammonia - Primary Amines
50
Q

How aggressive is the reaction between an acyl chloride and water?

A

Vigorous

51
Q

How aggressive is the reaction between an acyl chloride and alcohols?

A

Vigorous

52
Q

How aggressive is the reaction between an acyl chloride and ammonia?

A

Violent

53
Q

How aggressive is the reaction between an acyl chloride and a primary amine?

A

Violent

54
Q

What are the products of the reaction between an acyl chloride and water?

A

Carboxylic acid and HCl

55
Q

What are the products of the reaction between an acyl chloride and alcohol?

A

Ester and HCl

56
Q

What are the products of the reaction between an acyl chloride and ammonia?

A

Amide and HCl

57
Q

What are the products of the reaction between an acyl chloride and a primary amine?

A

N-substituted amide and HCl

58
Q

What is an acid anhydride?

A

Two identical carboxylic acid molecules joined by a -O-

59
Q

How aggressive are reactions between acid anhydrides and water, alcohol, ammonia and amines?

A

Less aggressive.

60
Q

What forms instead of HCl in a reaction with an acid anhydride rather than an acyl chloride?

A

Carboxylic acid.

61
Q

What type of mechanism is an acyl chloride reaction?

A

Nucleophilic Addition-Elimination.

62
Q

What are the reactants to form aspirin?

A

Salicylic acid with ethanoic anhydride or ethanoyl chloride.

63
Q

Why is ethanoic anhydride used in industry over ethanoyl chloride?

A
  • Cheaper - Safer - less corrosive and reacts more slowly and doesn’t produce HCl fumes.
64
Q

What type of reaction is the reduction of aldehydes/ketones?

A

Nucelophilic addition

65
Q

What are the conditions for the reduction of aldehydes/ketones?

A
  • reducing agent (NaBH4 dissolved in water with methanol)
66
Q

What type of reaction is potassium cyanide with aldehydes/ketones?

A

Nucleophilic Addition

67
Q

What are the conditions for the reaction of potassium cyanide with aldehydes/ketones?

A

KCN and a sulfuric acid catalyst

OR just HCN

68
Q

What type of reactions are acyl chlorides with water/alcohol/ammonia/primary amines?

A

Nucleophilic Addition-Elimination

69
Q

What are the conditions for the reaction between an acyl chloride and water?

A
  • cold water
  • room temp
70
Q

What are the conditions for the reaction between an acyl chloride and alcohol?

A
  • alcohol
  • room temp
71
Q

What are the conditions for the reaction between an acyl chloride and ammonia?

A
  • ammonia
  • room temperature
72
Q

What are the conditions for the reaction between an acyl chloride and primary amines?

A
  • amine
  • room temp
73
Q
A