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Alevel Chemistry OCR A > Module 4: Section 2- Alcohols, Haloalkanes And Synthesis > Flashcards

Module 4: Section 2- Alcohols, Haloalkanes And Synthesis Flashcards

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1
Q

Alcohols
What is the functional group

A

-OH

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2
Q

Alcohols
What’s the suffix for one alcohol

A

-ol

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3
Q

Alcohols
What is the suffix for two alcohol

A

-diol

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4
Q

Alcohols
What’s the prefix

A

Hydroxy-

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5
Q

Alcohols
What are the three types of alcohol

A

Primary secondary and tertiary

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6
Q

Alcohols
What’s a primary alcohol

A

1 carbon around the carbon of the OH group
(End of chain )

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7
Q

Alcohols
Notation for a primary alcohol

A

1°

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8
Q

Alcohols
What’s a secondary alcohol

A

2 carbon around carbon with OH group
(In chain)

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9
Q

Alcohols
Notation for secondary alcohol

A

2°

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10
Q

Alcohols
What is a tertiary alcohol

A

3 carbon around carbon with OH group
Branched

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11
Q

Alcohols
Notation for tertiary alcohol

A

3°

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12
Q

Alcohols
Are alcohols polar

A

Yes due to the electronegative hydroxyl group which pulls the electrons in the C-OH bond away from the carbon atom

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13
Q

Alcohols
What type of IMF can alcohols form

A

Hydrogen bonds

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14
Q

Alcohols
Compared to alkanes what is alcohols solubility like

A

High water solubility

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15
Q

Alcohols
Why do alcohols have high water solubility

A

Hydrogen bonds form between the -OH and H2O so lets it mix freely

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16
Q

Alcohols
What happens to water solubility as alchohl gets larger and why

A

Solubility decreases because most of the molecule is non polar so there’s less attraction for the polar H2O

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17
Q

Alcohols
Do alcolhs have low or high melting and boiling points compared to alkanes and why

A

Hydrogen bonds formed between alcohols which are the strongest type of IMF and requires the most energy to overcome

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18
Q

Alcohols
Are alcohol volatile

A

Relative low volatility compared to alkanes

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19
Q

Reactions of alcohols
What is combustion

A

Burnt in oxygen

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20
Q

Reactions of alcohols
What is produced in the combustion of alcohol

A

CO2 and H2O

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21
Q

Reactions of alcohols
Why are alcohols more likely to undergo complete combustion in comparison to incomplete combustion that alkanes

A

Already have oxygen in structure

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22
Q

Reactions of alcohols
Important to remember whilst balancing equation fo combustion

A

Oxygen atom in the alcohol

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23
Q

Reactions of alcohols
What is dehydration

A

Removal of H2O

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24
Q

Reactions of alcohols
In dehydration where is the H2O removed form

A

Loses the -OH and -H groups

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25
Q

Reactions of alcohols
What does dehydration produce

A

A new Alkene and water

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26
Q

Reactions of alcohols
What type or reaction is dehydration

A

Elimination

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27
Q

Reactions of alcohols
What is the conditions for dehydration

A

An acid catalyst and reflux (heat)

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28
Q

Reactions of alcohols
What acid catalysts can be used for dehydration

A

Concentrated sulfuric acid or concentrated phosphoric acid

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29
Q

Reactions of alcohols
How many products can be formed by dehydration

A

Often multiple as hydrogen can be removed from either side of -COH and EZ isomerism can be present

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30
Q

Reactions of alcohols
What happens in a substitution reaction

A

-OH group substituted by a halide when reacted with compounds containing halide ions

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31
Q

Reactions of alcohols
What formed in a substitution reaction with halide ion

A

Haloalkane

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32
Q

Reactions of alcohols
How does an alcohol have to be heated for substitution and with what

A

Heated under reflux with sulfuric acid and a sodium halide

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33
Q

Reactions of alcohols
For substitution when is hydrogen halide formed

A

In situ in the reaction

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34
Q

Reactions of alcohols
For substitution what is the equation for when the hydrogen halide is formed egwith Br

A

NaBr + H2SO4 —> NaHSO4 + HBr

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35
Q

Reactions of alcohols
For substitution what is the general reaction for just alcohol with hydrogen halide after being formed in situ

A

Alcohol + hydrogen halide —> haloalkane + water

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36
Q

Reactions of alcohols
Overall general equation for substitution of alcohol

A

Alcohol + H2SO4 + NaBr —> haloalkane + H2O + NaHSO4

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37
Q

Reactions of alcohols
What are the two methods to heat an alcohol for oxidation

A

Distillation
Reflux

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38
Q

Reactions of alcohols
What does distillation do

A

Heat gently and remove products as its formed

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39
Q

Reactions of alcohols
What does distillation prevent

A

Further reaction of product

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40
Q

Reactions of alcohols
What needs to be considered for distillation

A

How to heat organic substance as may be flammable

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41
Q

Reactions of alcohols
How does reflux work

A

Substance evaporated then recondensed and returns back to substance in flask by continuous heating

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42
Q

Reactions of alcohols
Why in reflux is the top open

A

So pressure doesn’t build up

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43
Q

Reactions of alcohols
What does oxidation of a alcohol require

A

An oxidising agent

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44
Q

Reactions of alcohols
What is an oxidising agent

A

Oxidise other species by gaining electrons and are reduced themselves

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45
Q

Reactions of alcohols
How is oxidising agent shown in reactions

A

[o]

46
Q

Reactions of alcohols
What oxidising agent is used in oxidation

A

Acidified potassium dichromate

47
Q

Reactions of alcohols
What colour is acidified potassium dichromate

A

Orange then goes green when reduced

48
Q

Reactions of alcohols
How do you know when alcohol has been oxidised

A

When the oxidising agent is reduced and changes colour

49
Q

Reactions of alcohols
What happens if you partially oxidise a primary alcohol

A

Forms aldehyde on primary carbon

50
Q

Reactions of alcohols
To partially oxidise a primary alcohol what method should be used

A

Distillation

51
Q

Reactions of alcohols
What is formed if you fully oxidise a primary alcohol

A

Carboxylic acid

52
Q

Reactions of alcohols
To fully oxidise a primary alcohol what method should be used

A

Reflux

53
Q

Reactions of alcohols
Equation for partially oxidising a primary alcohol (but an-1-ol)

A

Butan-1-ol + [o] —> butanal + water

54
Q

Reactions of alcohols
Equation for fully oxidising porimary alcohol butan-1-ol

A

Butan-1-ol + 2[o] —> butanoic acid + water

55
Q

Reactions of alcohols
What is formed when secondary alcohol is oxidised

A

Forms ketone on secondary C

56
Q

Reactions of alcohols
What method is best to use to oxidise a secondary alcohol and why

A

Reflux so all compound reacted

57
Q

Reactions of alcohols
Equation of oxidising secondary alcohol but an-2-ol

A

Butan-2-ol + [o] —> butanone + water

58
Q

Reactions of alcohols
What happens when tertiary alcohol oxidised

A

No reaction and acidified potassium dichromate remains orange

59
Q

Reactions of alcohols
Why can’t tertiary alcohols be oxidised

A

Because C atom whcih has -OH group has 3 other C atoms bonded to it and no H atom, in oxidation the carbon atom with the -OH group b=must be able to release an attached atom to form double C=O bond,
C-H bond easily broken but not C-C bond

60
Q

Haloalkanes
What are they

A

Compound containing carbon, hydrogen and at least one halogen

61
Q

Haloalkanes
Suffix for chlorine

A

Chloro-

62
Q

Haloalkanessuffix for bromine

A

Bromo-

63
Q

Haloalkanes
Suffix for iodine

A

Iodo-

64
Q

Haloalkanes
Suffix for fluorine

A

Fluoro-

65
Q

Haloalkanes
What can they be classified as

A

Primary
Secondary
Tertiary

66
Q

Haloalkanes
What is a primary haloalkane

A

Halogen at end of chain
C only attached to one other C

67
Q

Haloalkanes
What is a secondary haloalkane

A

Halogen in chain
C attached to two other C

68
Q

Haloalkanes
What is a tertiary haloalkane

A

Halogen at a branch
C attached to three C

69
Q

Haloalkanes
What bond is polar in haloalkanes

A

Carbon-halogen bond

70
Q

Haloalkanes
Why is the carbon-halogen bond polar

A

Halogens is more electronegative than carbon so electron pair in covalent bond is closer to halogen

71
Q

Haloalkanes
What is definition for nucleophile

A

Electron pair don’or

72
Q

Haloalkanes
What actually is a nucleopjhile

A

Atom or group which is attracted to a positive centre where is donates a pair of electrons to form a new covalent bond

73
Q

Haloalkanes
Where is a nucleophile attracted to on a haloalkane

A

Electron deficient slightly positive carbon atom

74
Q

Haloalkanes
Example of three nucleophile

A

:OH-
H2O:
:NH3

75
Q

Haloalkanes
What is nucleophilic substitution for a haloalkane

A

When haloalkane reacts with a nucleophile replaces the halogen in a substitution reaction

76
Q

Haloalkanes]
What does the rate of the nucleophilic substitution reaction depend on

A

Strength/length of the C-halogen bond

77
Q

Haloalkanes
Ranking for rate of substitution reaction for each halogen-carbon bond

A

C-I>C-Br>C-Cl>C-F

78
Q

Haloalkanes
In general, what is a hydrolysis reaction

A

Reaction involving water or aqueous solution of a hydroxide that causes breaking of a bond and molecule split into two products

79
Q

Haloalkanes
What happens in the hydrolysis of a haloalkane

A

Halogen atom replaced by an -OH group

80
Q

Haloalkanes
General equation for hydrolysis

A

Haloalkane + OH- —> alcohol + halide

81
Q

Haloalkanes
What is the process for hydrolysis (6)

A
  1. Nucleophile (OH-) attracted to slightly + carbon atom on opposite side from halogen
  2. Direction of attack minimises repulsion between nucleophile , -OH and delta- halogen
  3. Lone pair of electrons on OH- is donated to the + on the delta + carbon atom
  4. New bond formed between oxygen on OH- and carbon atom
  5. Carbon-halogen bond breaks through heterolytic fission
  6. Alcohol and halide ion formed
82
Q

Haloalkanes
Hydrolysis

A

LEARN MECHANISN

83
Q

Haloalkanes
Reagent needed for hydrolysis

A

NaOH

84
Q

Haloalkanes
Conditions needed for hydrolysis

A

Warm, aqueous

85
Q

Haloalkanes
Equation for hydrolysis of chloroethane

A

C2H5Cl + NaOH —> C2H5OH + NaCl

86
Q

Haloalkanes
What side of the haloalkane is a nucleophile added onto

A

Opposite halogen

87
Q

Haloalkanes
Practical for hydrolysis of haloalkanes method

A

Hydrolysis of haloalkanes
Set up three test tubes as follows:
Tube 1: Add 1 cm3 of ethanol and two drops of
I-chlorobutane
Tube 2: Add I cm3 of ethanol and two drops of
I-bromobutane
Tube 3: Add I cm3 of ethanol and two drops of
I-iodobutane
2 Stand the test tubes in a water bath at 60 oc.
3 Place a test tube containing 0.1 mol drn-3 silver
nitrate in the water bath and allow all tubes to reach a
constant temperature.
4 Add lcm3 of the silver nitrate quickly to each of the
test tubes. Immediately start a stop-clock.
5 Observe the test tubes for five minutes and record
the time taken for the precipitate to form.
.

88
Q

Haloalkanes
Practical for hydrolysis results

A

Chloro- form a white precipitate very slowly
Bromo- forms cream precipitate moderately time
Iodo- yellow precipitate very quickly

89
Q

Haloalkanes
For practical of hydrolysis How are the products identifies

A

Using silver nitrate

90
Q

Haloalkanes
Why does C-I bond hydrolyse the quickest

A

Weakens bond due to its bond enthalpy

91
Q

Haloalkanes
Why does the C-Cl bond hydrolyse the slowest

A

Strongest bond due to its bond enthalpy

92
Q

Haloalkanes
What maintains the ozone level for life on earth

A

The equilibrium

93
Q

Haloalkanes
Why are oxygen radicals present in the ozone layer

A

Uv light causes homoltic fission

94
Q

Haloalkanes
Equation for homolytic fission of oxygen

A

O2 -> 2 O

95
Q

Haloalkanes
What is the quilibrium equation to maintain ozone levels

A

O2 + O <=> O3

96
Q

Haloalkanes
What was originally used in fridges and why was it bad

A

NH3(l) was unhealthy

97
Q

Haloalkanes
What was found that could be used in fridges

A

CFCs

98
Q

Haloalkanes
What are CFCs

A

Chlorofluorocarbons

99
Q

Haloalkanes
Example of CFC

A

Freeon CCl2F2

100
Q

Haloalkanes
What are the three properties of CFCs

A

Volatile, non flammable and low toxicity

101
Q

Haloalkanes
What happened to the ozone layer in the 1990s

A

Depletion started

102
Q

Haloalkanes
Initiation equation for depletion of ozone using CF2CL2

A

CF2Cl2 –uv—> Cl. + CF2Cl.

103
Q

Haloalkanes
Propagation for depletion of ozone using CF2Cl2

A
  1. Cl. +O3 —> ClO. + O2
  2. ClO. + O —> O2 + Cl.
104
Q

Haloalkanes
Where does O cone from in the depletion if ozone

A

Already in the mixture from equilibrium

105
Q

Haloalkanes
What is the overall equation for depletion of ozone

A

O3 + O —> 2 O2

106
Q

Haloalkanes
Is CFCs rhe only way for depletion of ozone

A

Other radicals present can also break down ozone

107
Q

Haloalkanes
What radical often breaks down ozone

A

NO.

108
Q

Haloalkanes
What are NO. Radica,s formed from

A

Lightning storms and aircraft travel

109
Q

Haloalkanes
Propagation of depletion of ozone by NO. Radicals

A

NO. + O3 —> O2 + NO2.
NO2. + O —> NO . + O2

110
Q

Haloalkanes
Overall equation for depletion of ozone for NO. Radicals

A

O3 + O —> 2 O2

Alevel Chemistry OCR A (14 decks)

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