Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry > Chem 15 - Alcohols > Flashcards

Chem 15 - Alcohols Flashcards

(59 cards)

Start Studying
1
Q

What is the functional group symbol for alcohols?

A

-OH

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

what is the general formula of alcohols?

A

CnH2n+1OH

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

How many lone pairs of electrons does oxygen have?

A

2 lone pairs

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

What is the bond angle of O-H bond?

A

104.5

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

What do lone pairs do to each other?

A

Repel each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In primary alcohols how many R groups are attached to the carbon with the OH group attached?

A

One R group

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

In primary alcohol where is the OH group?

A

At the end of the chain

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

In secondary alcohols how many R groups are attached to the carbon with the OH group attached

A

Two R groups

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

In secondary alcohols where is the -OH group?

A

In the body of the chain

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

In tertiary alcohols how many R groups are attached to carbon with the OH group attached

A

3 R groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When alcohols are dehydrated what are formed?

A

alkenes

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

Why do we dehydrate alcohols?

A

to produce alkenes from renewable resources; this means you can produces polymers without needed oil

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

What is ethanol heated with to be dehydrated to ethene?

A

Concentrated sulphuric acid catalyst

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

Dehydration of more complicated alcohols can result in what?

A

More than one possible product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is distillation used to for?

A

To separate chemicals

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

Why do we need to distill an alcohol once it has been dehydrated (and is now an alkene)

A

To get a pure alkene because once an alcohol is dehydrated the mixture at the end contains the product, the reactant, acid and water

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

How do boiling points play a part in distillation?

A

Different chemicals have different boiling points therefore they can be separated

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

Explain the process of distillation of how to produce an alkene from an alcohol (4 marks)

A

1) add conc sulphuric acid and phosphoric acid to round bottom flask containing cyclohexanol. Six solution by swirling flask then add boiling chips
2) Gently heat mixture to around 83 degrees
3) Chemicals with boiling points up to 83 degrees will evaporate. Warm gas rises out of flask to condenser that has cold water running through it therefore turns gas into liquid
4) product can be collected in a cooled flask

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

Why do you need anti bumping granules/ boiling chips in distillation

A

help the mixture boil calmly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Explain the process of separation in how to produce an alkene from an alcohol (3 marks)

A

1) product contained after distillation still has impurities
2) transfer product mixture to a funnel and add water to dissolve water soluble impurities and create aqueous solution
3) allow mixture to settle into layers. Drain the aqueous lower layer leaving impure cyclohexane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Explain the process of purification in how to produce an alkene from an alcohol (3 marks)

A

1) drain the cyclohexane into round bottomed flask
2) add anhydrous calcium chloride and stopper the flask. Let mixture dry for 20 mins
3) the cyclohexane will still have small amounts of impurities so distil mixture one more time

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

What happens when you hydrate alkenes?

A

Alcohols are produced

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

What is the standard industrial method for producing alcohols?

A

To hydrate an alkene using steam in the presence of an acid catalyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How can ethanol be produced industrially?

Study These Flashcards
A

By fermentation

25
Explain the process of production of ethanol by fermentation of glucose (5 marks)
1) fermentation is an exothermic process carried out by yeast in anaerobic conditions 2) yeast produces an enzyme which converts sugars into ethanol and carbon dioxide 3) the enzyme works at an optimum temperature of 30-40 degrees, if its too cold reaction is slow if too hot the enzyme is denatured 4) once from ethanol is separated from the rest by fractional distillation 5) fermentation uses cheap equipment and renewable, but factional distillation takes time and money
26
What is a biofuel?
A fuel that is made from biological material thats recently died
27
Give an example of a biofuel.
Ethanol
28
List 2 advantages of using biofuels over fossil fuels
1) biofuels are renewable energy sources unlike fossil fuels, biofuels won't run out therefore they are more sustainable 2) biofuels produce carbon dioxide when they are burnt but carbon dioxide is absorbed by plants therefore is classed as carbon neutral
29
List 2 disadvantages of using biofuels
1) petrol engine cars would have to be modified to use fuels with high ethanol concs 2) when you use land to grow crops for fuel, that land cannot be used to grow food
30
Is bioethanol production carbon neutral?
Almost but not quite
31
Why is bioethanol production thought to be carbon neutral by some people?
during ethanol prodcues carbon dioxide however plants that are grown to produce bioethanol take in carbon dioxide from the atmosphere when they are growing. They take in the same amount of carbon dioxide as burning the bioethanol produces.
32
Why is bioethanol production thought to not be carbon neutral by some people?
Bioethanol production produces carbon dioxide which is a greenhouse gas. Fossil fuels will need to be burned to power the machinery used to make fertilisers for the crops
33
How much an alcohol can be oxidised depends on what?
It's structure
34
What is the name of the oxidising agent used to mildly oxidise alcohols
acidified potassium dichromate (K2Cr2O7)
35
What can primary alcohols be oxidised to?
aldehydes then to carboxylic acids
36
What can secondary alcohols be oxidised to?
Ketones
37
What can tertiary alcohols be oxidised to?
Nothing
38
What is the functional group symbol of carboxylic acids
COOH
39
What is the structure of aldehydes?
They have a hydrogen and one alkyl group attached to the carbonyl carbon atom. Suffix is -al. It is always attached to carbon-1
40
What is the structure or ketones?
Have two alkyl groups attached to the carbonyl carbon atom . Suffix is -one
41
What is the structure of carboxylic acids?
Have a COOH group at the end of their carbon chain. Their suffix is -oic acid
42
How can you control how far the alcohol is oxidised?
By controlling their reaction conditions
43
How do you produce a ketone from a secondary alcohol?
refluxe
44
How can you distinguish between aldehydes and ketones?
By using oxidising agents, aldehydes are easily oxidised but ketones aren't
45
Name the two oxidising agents you can use to distinguish between aldehydes and ketones?
1) Fehling's Solution | 2) Tollens' reagent
46
What happens when Fehling's solution is added to an aldehyde and ketone?
It is deep blue but reduces to brick red when heated with an aldehyde however it stays blue with a ketone
47
What happens when Tollens' reagent is added to an aldehyde and ketone?
It's reduced to silver when warmed with an aldehyde but not with a ketone. Creates a silver mirror
48
What's the test to distinguish between primary, secondary and tertiary alcohol?
- Add alcohol to acidified potassium dichromate - warm the mixture gently - watch for colour change
49
What colour does the solution change to when the alcohol is primary?
Orange solution slowly turns green as an aldehyde forms
50
What colour does the solution change to when the alcohol is secondary?
Orange solution slowly turns grey as ketone forms
51
What colour does the solution change to when the alcohol is tertiary?
nothing happens
52
As the result for a primary and secondary alcohol is the same, what do you do to distinguish between the two?
Repeat the experiment and collect some of the product but using a flask as part of distillation apparatus. You can then test if you have an aldehyde or ketone by using Fehling's solution or Tollen;s reagent
53
How does the Fehling's solution test work? (3 marks)
1) Add Fehling's solution to a test tube 2) Add 5 drops of the aldehyde or ketone to the test tube 3) Put the test tube in a hot water bath to warm it for a few mins
54
How does the Tollens' reagent test work? (4 marks)
1) Put 0.10 mol dm-3 silver nitrate in a test tube 2) Add a few drops of dilute sodium hydroxide solution and a light brown precipitate should form 3) Add drops of dilute ammonia solution until brown precipitate dissolves 4) Place tets tube in hot water bath and add 10 drops of aldehydes or ketone and wait for a few minutes
55
What is the test for alkenes?
Use bromine water
56
How does the bromine water test work? (3 marks)
1) add the solution you want to test into a test tube 2) Add bromine water 3) shake the test tube, if an alkene is present the solution will decolourise.
57
What do you use to test for carboxylic acids?
Sodium carbonate
58
Carboxylic acids react with carbonates to form what?
Salt, carbon dioxide and water
59
How does the test for carboxylic acids work? (3 marks)
1) Add the solution you want to test to a test tube 2) Add 1 spatula of sodium carbonate 3) if the solution begins to fizz, bubble the gas that it produces through some limewater in a second test tube. If a carboxylic acid is present the solution will fizz. The carbon dioxide gas that is produced will turn limewater cloudy

Chemistry (10 decks)

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