alcohols part 1 Flashcards Preview

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Flashcards in alcohols part 1 Deck (44)
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1
Q

general formula

A

CnH2n+1OH

2
Q

functional group

A

-OH

3
Q

what can alcohols be classified as

A

primary, tertiary or secondary

4
Q

what do primary alcohols have

A

1 variable group attached to the same carbon as the OH(besides the OH)

5
Q

what do secondary alcohols have

A

2 variable groups attached to the same carbon as the OH (besides the OH)

6
Q

what do tertiary alcohols have

A

3 variable groups attached to the same carbon as the OH (besides the OH)

7
Q

what must be indicated if there are 3 or more carbon atoms in the molecule

A

the position of the OH group

8
Q

structural isomers

A

compounds with the same molecular formula but different structural formula

9
Q

why do alcohols have relatively high melting and boiling points

A

they form hydrogen bonds

10
Q

which alcohols are soluble in water

A

those with a low Mr

11
Q

why are alcohols with a low Mr soluble in water

A

hydrogen bonding

12
Q

how are alcohols generally prepared industrially

A

by hydration of alkenes

13
Q

what is the reagent in the production of alcohols by the hydration of alkenes

A

the alkene and steam

14
Q

what conditions are needed for the production of alcohols by the hydration of alkenes

A
  • phosphoric acid catalyst

- high temp and pressure

15
Q

how can the mechanism of hydration be shown

A

using curly arrows

16
Q

curly arrows

A

shows the movement of a pair of electrons

17
Q

what is the role of the H+ ion in the hydration of alkenes

A

catalyst (its regenerated)

18
Q

uses of ethanol

A
  • alcoholic beverage industry
  • sterilising medical equipment
  • solvents/fuel
19
Q

what are the two different methods for the industrial preparation of ethanol

A
  • fermentation

- hydration of ethene

20
Q

examples of carbohydrate crops used in fermentation

A

sugar cane/sugar beet

21
Q

what are carbohydrate crops broken down into during fermentation

A

sugars such as glucose

22
Q

how are the sugars converted into ethanol during fermentation

A

by anaerobic respiration

23
Q

how is ethanol removed from the reaction mixture in fermentation

A

by fractional distillation

24
Q

what is the reagent in fermentation

A

sugar

25
Q

conditions needed for fermentation

A

water, 30-35 degrees Celsius, yeast, lack of O2

26
Q

equation for fermentation

A

C6H12O6> 2C2H5OH + 2CO2

27
Q

why is air kept out of the fermentation reaction

A

prevents oxidation of alcohol into vinegar

28
Q

why must a compromise temperature of 35 degrees celcius be used

A

optimum temp for yeast

29
Q

why does the fermentation stop when the reaction mixture contains about 15% ethanol

A

at this level of alcohol the yeast is poisoned

30
Q

what is fractional distillation

A

separating two or more liquids with differing boiling points eg ethanol and water

31
Q

why should you heat the flask during fractional distillation

A

it causes the water and ethanol to vapourise

32
Q

what happens as a result of the vapour passing up the fractionating column in fractional distillation

A

the water and ethanol will separate

33
Q

why will water condense back into the flask in fractional distillation

A

it has a higher boiling point than ethanol

34
Q

observe the temperature and keep the temperature at or just below… (FD)

A

the boiling point of ethanol

35
Q

where does ethanol vapour pass into during fractional distillation

A

the condenser

36
Q

what does the condenser do in fractional distillation

A

cools the ethanol vapour back into a liquid which is collected in a conical flask

37
Q

reagents in hydration of ethene

A

ethene and steam

38
Q

conditions in hydration of ethene

A

phosphoric acid catalyst

300 degrees celcius and 60atm

39
Q

equation for hydration of ethene

A

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

40
Q

comparison of the two processes that produce ethanol: raw material

A

H: crude oil (finite)
F: sugar (renewable)

41
Q

comparison of the two processes that produce ethanol: quality of product

A

H: pure
F: very impure

42
Q

comparison of the two processes that produce ethanol: rate of reaction

A

H: very fast
F: slow

43
Q

comparison of the two processes that produce ethanol: energy requirements

A

H: high energy use
F: low energy use

44
Q

comparison of the two processes that produce ethanol: type of process

A

H: continuous
F: batches