Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

AQA: Chemistry Paper 2 > Alcohols > Flashcards

Alcohols Flashcards

(55 cards)

Start Studying
1
Q

What is the general formula of an alcohol?

A

CₙH₂ₙ₊₁OH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Volatility of alcohols:

A

low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Boiling points of alcohols:

A

high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why do alcohols have high boiling points?

A

high boiling points due to their ability to form

hydrogen bond between alcohol molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the different types of alcohols?

[3]:

A
  • Primary alcohols
  • Secondary alcohols
  • Tertiary alcohols
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What makes a secondary alcohol?

A

Secondary alcohols are alcohols where 2 carbon are attached to the carbon with the functional group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens when you oxidise a primary alcohol?

A

An aldehyde is formed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Partial oxidation of primary alcohols:

A

primary alcohol → aldehyde

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the reagents in the partial oxidation of primary alcohols?
[2]:

A
  • potassium dichromate (VI) solution

- dilute sulfuric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the conditions in the partial oxidation of primary alcohols? [3]:

A
  • Limited amount of potassium dichromate (VI)
  • Warm gently
  • Distil out the aldehyde
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the dichromate ion look like?

A

Cᵣ₂O₇²⁻

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What would you observe when dichromate ions are reduced? [2]:

A
  • Orange → Green

- Cᵣ₂O₇²⁻ reduced to Cr³⁺

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do you do when writing the formula of aldehydes in a condensed way?

A

write CHO and not COH

e.g.CH₃CH₂CHO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Distillation equipment [5]:

A
  • Thermometer
  • Bung
  • Heat
  • Leibig condenser
  • Collection flask
  • Anti bumping granules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where should the thermometer be during distillation and why?

A
  • At the T junction connecting to the condenser

- To measure the correct boiling point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why are electric heaters often used to heat organic chemicals?

A

Organic chemicals are normally highly flammable and could set on fire with a naked flame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Full Oxidation of Primary Alcohols:

A

primary alcohol → carboxylic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the reagents for the full oxidation of primary alcohols? [2]:

A
  • potassium dichromate(VI) solution

- dilute sulfuric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the conditions for the full oxidation of primary alcohols? [3]:

A
  • an excess of dichromate
  • heat
  • under reflux
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is reflux used for? [2]:

A
  • Reflux is used when heating organic reaction mixtures for long periods
  • The condenser prevents organic vapours from escaping
    by condensing them back to liquids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why do you never seal the end of the condenser during reflux?

A

build up of gas pressure could cause the apparatus to explode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why are anti bumping granules added to the flask during distillation and reflux?

A

To prevent vigorous, uneven boiling by making small bubbles form instead of large bubbles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Reflux equipment [4]:

Study These Flashcards
A
  • Anti-bumping granules
  • Round-bottomed flask
  • Heat
  • Condenser
24
Q

Oxidation of secondary alcohols:

Study These Flashcards
A

secondary alcohol → ketone

25
What are the reagents for the oxidation of secondary alcohols? [2]:
- potassium dichromate(VI) solution | - dilute sulfuric acid
26
What are the conditions for the oxidation of secondary alcohols?
heat under reflux
27
Observation for the oxidation of secondary alcohols?
the orange dichromate ion Cᵣ₂O₇²⁻ reduces to the green Cr³⁺+ ion
28
Why can tertiary alcohols not be oxidised by potassium dichromate?
There is no hydrogen | atom bonded to the carbon with the -OH group
29
What is the difference between aldehydes and ketones?
Aldehydes can be further oxidised to carboxylic acids whereas ketones cannot be further oxidised
30
What tests are used to distinguish between aldehydes and ketones? [2]:
- Tollens’ Reagent | - Fehling’s solution
31
How is Tollens’ reagent formed? | [2]:
- By mixing aqueous ammonia and silver nitrate. | - Forms the ion [Ag(NH₃)₂]⁺
32
What are the conditions for Tollens’ reagent?
Heat gently
33
Tollens’ reagent observation | [2]:
- Aldehydes = silver mirror | - Ketones = no visible change
34
What does Fehling's solution contain?
Blue Cu²⁺ ions
35
What are the conditions for Fehling's solution?
Heat gently
36
Fehling's solution observations | [2]:
- Aldehydes = Blue Cu 2+ ions in solution change to a red precipitate of Cu₂O - Ketones = no visible reaction
37
How else can a carboxylic acid be tested for? | [2]:
- Tested by addition of sodium carbonate | - It will fizz and produce carbon dioxide
38
Reaction of Alcohols with Dehydrating Agents:
Alcohol → Alkene
39
Reagents for the reaction of alcohols with dehydrating agents? [2]:
Concentrated sulfuric or phosphoric acids
40
What are the conditions for the reaction of alcohols with dehydrating agents?
Warm under reflux
41
What is the mechanism for the reaction of alcohols with dehydrating agents?
elimination
42
What does producing alkenes from alcohol provide?
provides a possible route to polymers without using monomers derived from oil
43
What are the methods for the formation of ethanol? | [2]:
- Fermentation | - Industrial formation from ethene
44
What are the conditions for fermentation? [3]:
- Yeast - No air/ anaerobic - Temperatures 30-40ᵒC
45
What is the optimum temperature for fermentation and why? [3]:
- Around 38ᵒC - At lower temperatures the reaction is too slow. - At higher temperatures the yeast dies and the enzymes denature
46
Why is fermentation done in the absence of air? | [2]:
- The presence of air can cause extra reactions to occur. - It oxidises the ethanol produced to ethanoic acid (vinegar)
47
Advantages of fermentation [2]:
- Sugar is a renewable resource - Production uses low-level technology / cheap equipment
48
Disadvantages of fermentation [3]:
- Batch process is slow and gives high production costs - Ethanol made is not pure and needs purifying by fractional distillation - Depletes land used for growing food crops
49
What type of reaction is the industrial formation of ethanol from ethene?
Hydration/ addition
50
Conditions for the industrial formation of ethanol from ethene [3]:
- high temperature 300 °C - high pressure 70 atm - strong acidic catalyst of conc H₃PO₄
51
What are the advantages of the industrial formation of ethanol from ethene? [3]:
- faster reaction - purer product - continuous process (which means cheaper manpower)
52
What are the disadvantages of the industrial formation of ethanol from ethene? [3]:
- high technology equipment needed (expensive initial costs) - ethene is non-renewable resource (will become more expensive when raw materials run out) - high energy costs for pumping to produce high pressures
53
What is ethanol?
A biofuel produced from plants
54
What is the ethanol produced from fermentation?
A biofuel
55
What does carbon neutral mean?
an activity that has no net annual carbon (greenhouse gas) emissions to the atmosphere

AQA: Chemistry Paper 2 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions