Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry - Module 4 > 14 - Alcohols > Flashcards

14 - Alcohols Flashcards

You may prefer our related Brainscape-certified flashcards:
Chemistry 101 flashcards WSET ® Level 4 D2 Business of Wine flashcards AP® Chemistry flashcards Periodic Table flashcards Organic Chemistry 101 flashcards
1
Q

What are the physical properties of alcohols compared to alkenes of the same length

A

o Are less volatile
o Have higher melting points
o Are more soluble in water

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

Do the differences increase or decrease as the length of the carbon chain increases

A

Decrease

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

Alcohols vs alkanes = strength of London forces

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

Do alkanes or alcohols have a higher boiling point

A

Alcohols = • Hydrogen bonds between alcohol molecules requires more energy to overcome than the weak London forces between alkane molecules

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

Explain this graph

A

• as the chain length increases, the contribution of the –OH group decreases and the alcohols resemble the alkanes more closely.

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

Are alcohols soluble in water

A

Yea

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

Why are alcohols soluble in water

A

• H bonds form between -OH group = very soluble

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

How do we classify alcohols

A

on number of H-atoms and R-groups attached to the C-atom that contains the OH group

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

What is a primary alcohol

A

1 R group

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

What is a secondary alcohol

A

Two R groups

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

What is a tertiary alcohol

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

What are the products when alcohols combust

A

• Same products as complete combustion of alkanes (carbon dioxide + water)

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

What type of reaction is the combustion of alcohols

A

Exothermic

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

How does chain length impact the combustion of alcohol

A

• The longer the chain, the more energy released per mole

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

Can primary alcohols oxidise

A

Yes

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

What product is formed when primary alcohols are oxidised

A

• Product = aldehyde, but can be further oxidised to form carboxylic acids

17
Q

How to oxidise alcohol into an aldehyde

A

o Gentle heating with acidified potassium dichromate (H2SO4/K2Cr2O7 ) and primary alcohol

o Aldehyde must be distilled out as its formed (has lower B.P than alcohol so can be distilled)

o Prevents further oxidation into a carboxylic acid

o Dichromate (VI) ions turn from orange to green
chromium (III) ions

18
Q

Has the dichromate ions been oxidised or reduced when making an aldehyde

A

Cr2O72- to Cr3+
- Has been Reduced

19
Q

Product when ethanol has been oxidised

A
20
Q

How to make a carboxylic acid from an aldehyde

A

o If the aldehyde is not distilled off, further refluxing with excess oxidising agent will oxidise it to a carboxylic acid

21
Q

Can secondary alcohols be oxidised

A

Yes

22
Q

What the product when a secondary alcohol is oxidised

A

Ketones

23
Q

Does ketone need to be distilled off straight away and why

A

• Since ketones cannot be further oxidised, the ketone product does not need to be distilled off straight away after it has been formed

24
Q

Write an equation for the oxidation of propan - 2 - ol

A
25
Q

Can tertiary alcohols be oxidised

A

No

26
Q

How would I turn alcohols into an alkene

A

Through the ELIMINATION REACTION

27
Q

What is the elimination reaction also known as

A

The dehydration of alcohols

28
Q

Process to dehydrate an alcohol

A

• Alcohol heated under reflux with an acid catalyst

o Excess hot, concentrated sulfuric acid or phosphoric acid is used as a catalyst

29
Q

What type of catalyst is needed for dehydration

A

Hot concentrated sulfuric acid or phosphoric acid catalyst

30
Q

What is eliminated in a dehydration reaction

A

A water molecule

31
Q

What is the product of a dehydration reaction

A

Alkenes

32
Q

What will the substitution reaction in an alcohol form

A

Haloalkane

33
Q

How does the substitution reaction form a haloalkane

A

• a hydroxy group (-OH) is replaced by a halogen to form an haloalkane

34
Q

Two steps to form a haloalkane

A

Form hydrogen halide

And then haloalkane

35
Q

Process of substitution reaction

A

To prepare hydrogen halide
o Alcohol heated under reflux with sulfuric acid and a sodium halide (e.g., NaBr)
o Hydrogen halide formed in situ

To form haloalkanes
• Hydrogen halide reacts with alcohol to produce haloalkane

36
Q

Write out the full equation of the subitution reaction of propan-2-ol with bromine

A

Chemistry - Module 4 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions