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chemistry A1 organic > 3.3.5 Alcohols > Flashcards

3.3.5 Alcohols Flashcards

(86 cards)

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1
Q

why do alcohols have high boiling points

A

they can form hydrogen bonds with other molecules

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2
Q

what are the key points when naming alchols

A

drop the e with the prefix

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3
Q

what are the different ways to classify alcohols

A

primary
secondary
tertiary

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4
Q

what are primary alcohols

A

1 carbon is joined to the oxygen

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5
Q

what are secondary alcohols

A

the carbon joined with the oxygen is bonded to two other carbons

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6
Q

what are teritary alcohols

A

the carbon bonded to oxygen is joined to bonded to 3 carbons

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7
Q

what is the bonding present in alcohols

A

hydrogen bonding
van Deer Waal
dipole-dipole forces

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8
Q

what type of molecules are alcohols

A

polar molecules

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9
Q

are short chained alcohols soluble in water

A

yes

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9
Q

why does the solubility decrease to the longer carbon chain

A

greater region of non-polar molecules
which is highly insoluble

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10
Q

what can primary alcohols be oxidised into

A

aldehydes

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11
Q

what can aldehydes be oxidised into

A

carboxylic acids

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12
Q

what can secondary alcohols be oxidised into

A

ketones

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13
Q

what can tertiary alcohols be oxidised into

A

it cant be oxidised

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14
Q

why can primary and secondary alcohols be oxidised

A

the carbon-hydrogen bond breaks

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15
Q

what reagent oxidises primary and secondary alcohols

A

acidified potassium dichromate

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16
Q

what is the molecular formula for postassium dichromate

A

K2Cr2O7

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17
Q

what is the positive result for the oxidation of alcohols

A

orange to green

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18
Q

what acid acidifes potassium dichromate

A

sulfuric acid

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19
Q

what do alcohols lose **

A

2 hydrogens

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20
Q

what is thee half equation for chromium

A

Cr2O7^2- + 6e- + 14H+ –> 2Cr^3+ +7H2O

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21
Q

how can the oxidising agent be rrepresented as

A

[O]

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22
Q

what causes the green colour change

A

the chromium ion
Cr 3+

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23
Q

where is the water in on the fractional distillation column

A

the water in is always at the bottom

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24
what are the conditions of the oxidation of primary alcohols
acidifed potassium dichromate under reflux
25
what is reflux
where the vapour condenses back into the liquid
26
what is the function of the condenser?
prevents organic vapour from escaping by condensing them back to liquids
27
why should you never seal the condenser
there will be a build up of pressure and it will explode
28
what is a description of the condenser
the long thing with the water in and water out bit
29
why is water in at the bottom
to prevent the backflow of water
30
why are electric heaters used
organic chemicals are highly flammable
31
what is thee purpose of anti-bumping granules
to prevent vigorous, uneven boiling by making small bubbles form instead of largee bubbles
32
how do anti-bumping granules work
they form small bubbles instead of large bubbles
33
what are the reagents for the oxidation of alcohols
acidified potassium dichromate
34
what are the conditions for the oxidation of secondary alcohols
heat under reflux
35
why cant tertiary alcohols be oxidised
there is no hydrogen atom bonded to the carbon with the -OH group
36
what is produced under reflux
carboxylic acid and ketone
37
how can we extract ketones
using distillation
38
how can we produce aldehydes
distillation
39
what things shouldn't you include in a fractional column
- no gap between condenser and flask - dont draw lines between flask and condenser -dont forget the water in and water out section
40
what reagent is used to test for aldehydes andd ketones
Tollens' Reagent
41
what is the results for the Tollen's Reagent test
aldehydes- silver mirror ketones- no colour change
42
what is the positive result for aldehydes with the Tollens Reagent
silver mirror percipitate
43
what is the result for ketones when Tollens reagent is added
no colour change
44
what are the conditions for the Tollen's Reagent test
heated gently
45
what is another reagent used for the testing of aldehydes and ketones
Fehlings Solution
46
what are the results when aldehydes and ketones are tested by Fehling's solution
aldehydes: blue to brick red percipitate ketones: blu, no colour change
47
what is the positive results for the test using Fehling's solution
aldehydes: blue to brick red
48
how can we test for carboxylic acids
sodium hydrogencarbonate
49
what is observed when we test for carboxylic acids
fizzing and effervescent CO2 is produced
50
what is meant by a dehydration reaction
when a water molecule is removed
51
what is the type of reaction is a dehydration reaction
elimination reaction
52
what reagent is used in the elimination/dehydration reaction
concentrated acid catalyst
53
what type of acid catalyst is usd in the elimination reaction
concentrated sulfuric acid
54
how are alchols converted to alkenes
by an elimination reacttion
55
what is the general formula of the elimination reaction
alcohol -> alkene + water <-
56
what type of reaction is an elimination reaction
reversible reaction
57
what does producing alkenes from alcohols provide
a route to polymers
58
what is the hydration of alkenes involve
an acid catalyst and steam
59
why is the hydration of alkenes considered as electrophilic addition
cause sulfuric acid can act as an electrophile
60
what are the conditions for feermentation
yeast no oxygen temperarure: 25-40 degrees
61
what should the temperature be for fermentation
between 25 and 40 degrees
62
why shouldnt we use low temperatures for fermentation
the reaction would be too slow
63
what is thee purpose of yeast in fermenation
it has an enzyme which catalyses the process
64
what is the process of fermentation
add warm water to sugar then add yeast aking sure theres no O2
65
why shouldnt we carry out fermentation at high temperatures
the enxymes denature
66
why is fermentation done in the absence of air
air can oxidise ethanol into ethanoic acid (vinegar)
67
what is the balanced equation for the formation of ethanol from fermentation
2glucose--> 2ethanol + 2carbon dioxde
68
what are the disadvantages of fermentation of ethanol
- batch process which is slower - ethanol is not pure and is purified by fractional distillation - depletes lands for crops
69
how is ethanol separated from fermentation
fractional distillation
70
what are the advantages of the fermentation of ethanol
- sugar is a renewable source - cheaper - lower energy
71
where does the reagent from the industrial formation of ethene come from
ethene comes from cracking of crude oil
72
what is the reraction calledd for the industral formation of ethanol
hydration/elimination
73
what are the conditions in the industrial formation of ethene
- high temps 300 degrees - high pressure 6000kpa - acid catalst: H3PO4
74
what is the temperature when ethanol is made industrially
300 degrees
75
what is the pressure when ethanol is made industrially
6000 kPa
76
what catalyst is used when ethanol is made industrially
concentrated phosphoric acid
77
what are the advantages when ethanol is made industrially
- faster reaction - high percentage atom economy - purer product
78
with the hydration of alkenes what does the ouble bond attack
the delta positive H on the acid
79
what are the disadvantages when ethanol is made industrially
ethene is non-renewable high energy costs expensive
80
what attacks after the double bond attacks the hydrogen
the water
81
what is biofuel
a fuel made from plants
82
what is meant by the term carbon neutral
an activity that has no net carbon dioxide to the atmosphere
83
why is the prodution of ethanol considered as carbon neural
cause of the removal of 6CO2 in photosynthesis the production of 6CO2 from fermentation&combustion 6CO2 absorbed 6CO2 emitted
84
however, why isnt the formation of ethanol fully carbon neutral
CO2 is produced in transportation machinery and fertticlicers for plants
85

chemistry A1 organic (5 decks)

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