Alcohols (Chapter 15) Flashcards

1
Q

How are alcohos named?

A

-ol (usually after the number where the functional group is) e.g. butan-2-ol

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2
Q

What is the general formula for alcohols?

A

CnH(2n+1)OH

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3
Q

What is the prefix for a compound with an alcohol and another functional group?

A

Hydroxyl

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4
Q

Describe and explain the boiling points of alcohols

A

Relatively high boiling points as they are able to form hydrogen bonds between molecules.

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5
Q

Describe and explain the volatility of alcohols

A

Relatively low vocatively as they are able to form hydrogen bonds between molecules.

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6
Q

What is a primary alcohol?

A

Where one carbon is attached to the carbon adjoining the oxygen.

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7
Q

What is a secondary alcohol?

A

Where 2 carbons are attached to the carbon adjoining the oxygen.

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8
Q

What are tertiary alcohols?

A

Where there are 3 carbons attached to the carbon adjoining the oxygen.

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9
Q

What is used as an oxidising agent on alcohols?

A

Potassium Dichromate (IV) (also need dilute sulphuric acid)

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10
Q

What is produced when a primary alcohol is oxidised by distillation?

A

Aldehyde (+ water)

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11
Q

What is the functional group for an aldehyde?

A

CHO

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12
Q

What is the observation when alcohols are oxidised?

A

Orange dichromate 6+ ion reduces to green Cr3+

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13
Q

What are the conditions for oxidation of primary alcohol by distillation?

A

Warm gently and distil aldehyde as it forms.

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14
Q

What is produced when a primary alcohol is oxidised by reflux?

A

Carboxylic acid

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15
Q

What are the conditions for the oxidation of a primary alcohol by reflux?

A

Use excess of potassium dichromate and heat under reflux (distill off product after reaction has finished)

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16
Q

Why are anti-bumping granules?

A

To prevent vigorous, uneven boiling by making smaller bubbles.

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17
Q

What is produced when a secondary alcohol is oxidised?

A

Ketone

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18
Q

What are the condition for the oxidation of a secondary alcohol?

A

Heat under reflux

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19
Q

Why can’t tertiary alcohols be oxidised?

A

There is no hydrogen atom bonded to the carbon with the OH group.

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20
Q

What positive ion does tollens reagent contain?

A

[Ag(NH3)2]+

21
Q

What are the observation from pollens reagent?

A

Aldehydes form a coating on the inside of the test tube while ketones have no visible change?

22
Q

What positive ion does Feelings solution contain?

A

Blue Cu2+

23
Q

Describe the reaction when pollens is added to oxidised alcohols

A

Only aldehydes are oxidised by tollens to carboxylic acids and silver ions are reduced to silver atoms.

24
Q

What are the conditions for adding tollens reagent to an oxidised alcohol?

A

Heat gently

25
Q

What are the conditions for adding fehlings solution to oxidised alcohols?

A

Heat gently

26
Q

What is the observation when feelings reagent is added to oxidised alcohols?

A

Blue Cu2+ ions are changed to red precipitate of Cu2O

27
Q

Describe the reaction when oxidised alcohols are added to fehlings solution?

A

Aldehydes are oxidised to carboxylic acids and the Copper (II) ions are reduced to Copper (I)

28
Q

What is produced when an alcohol is dehydrated?

A

Alkene

29
Q

What are the reagent used to dehydrate an alcohol?

A

Concentrated sulphuric or phosphoric acid

30
Q

What is the role of the reaction when alcohols are dehydrated?

A

Dehydrating agent/catalyst

31
Q

What type of reaction is the dehydration of a alcohol?

A

Acid catalysed elimination

32
Q

Define dehydration?

A

The removal of a water molecule from a molecule.

33
Q

What are the condition for dehydrating an alcohol?

A

Warm under reflux

34
Q

What is the equation for the fermentation of glucose?

A

glucose > ethanol + carbon dioxide

C6H12O6 > 2CH3CH2OH + 2CO2

35
Q

What are the conditions for the fermentation of glucose/

A
  • Yeast
  • No air
  • Temperatures 30-40ºc
36
Q

Why is 38ºc the optimum temperature for the fermentation of glucose?

A

At lower the temperature the reaction is too slow.

At higher temperature the yeast dies and the enzymes denature.

37
Q

Why is the fermentation of glucose done in the absence of air?

A

The presence of air can cause other reactions to occur (e.g. it oxidises the ethanol to ethanoic acid)

38
Q

What are the advantages of the fermentation of glucose?

A
  • Sugar is a renewable resource
  • Production uses low amounts of energy
  • Cheap equipment
39
Q

What are the disadvantages of the fermentation of glucose?

A
  • Batch process which is slow and gives high production costs
  • Ethanol is not pure and need to be purified by fractional distillation.
  • Depletes land use for growing crops.
40
Q

How is ethene produced for the industrial formation of ethanol?

A

Cracking of fractions from crude oil

41
Q

What is the equation for the production of ethanol form ethene?

A

Ethene + Water > Ethanol

CH2=CH2 (g) + H2O (g) > CH3CH2OH (l)

42
Q

What type of reaction forms ethanol from ethene?

A

Hydration

43
Q

Define a hydration reaction

A

Addition of a water molecule to a molecule.

44
Q

What are the condition for producing ethanol from ethene?

A
  • High temperature of 300ºc
  • High pressure of 70 atm
  • Strong acidic catalyst of concentrated H3PO4
45
Q

What are the advantages of producing ethanol from ethene?

A
  • Faster reaction
  • Purer product
  • Continuous process
46
Q

What are the disadvantages of producing ethanol from ethene?

A
  • High technology equipment needed
  • Ethene is non-renewable resource
  • High energy cost to produce high pressure
47
Q

What is a biofuel?

A

Fuel produced from plants.

48
Q

Define carbon neutral

A

An activity that has no net annual carbon emission to the atmosphere.

49
Q

How is are carboxylic acids tested for?

A

Sodium carbonate and it will fizz and produce carbon dioxide.