Brainscape's Knowledge GenomeTM

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


See full index

Organic Chemistry > Carboxylic Acids > Flashcards

Carboxylic Acids Flashcards

1
Q

What is the functional group of a carboxylic acid?

A

-COOH

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

How are carboxylic acids formed?

A

Oxidising primary alcohols under reflux

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

Which carboxylic acids are more soluble?

Why?

A

Those with a lower Mr

The -COOH forms hydrogen bonds with water

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

Why are carboxylic acids only weak acids?

A

They only slightly dissociate in water

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

How is a carboxylate ion formed?

A

The carbonyl group attracts e- away from the -OH group which leads to the -OH bond being weakened so a proton is easily lost

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

Why are alcohols not acidic?

A

The -OH bond does not easily break

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

How does adding a halogen to a carboxylic acid affect the pH?

Eg chloroethanoic acid

A

Chlorine atom is more electronegative so withdraws e- density away from the carbonyl carbon. This causes the O-H bond to become more polar and weaken.
More H+ is therefore released, decreasing the pH

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

What is more acidic: ethanoic acid or chloroethanoic acid

Why?

A

chloroethanoic acid

Cl pulls e- towards itself

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

How are acyl chlorides formed?

A

The -OH group of the carboxylic acid is replaced by a chlorine atom

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

Why is the carbon atom in acyl chlorides readily attacked by nucleophiles?

A

Cl and O are more electronegative than C so the C atom is delta positive

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

How are acyl chlorides named?

A

It is derived from their corresponding carboxylic acid

Eg ethanoic acid forms ethanoyl Chloride

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

When there is an -OH in the middle of a carbon chain, how can you refer to it in the name?

A

With ‘hydroxy’

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

How to form acid anhydrides from carboxylic acids?

A

-OH group is replaced by -OCOR

When two molecules of carboxylic acids join with the elimination of water

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

How do you name an acid anhydride?

A

The suffix -anhydride replaces the -acid suffix at the end of the carboxylic acid name

If the two C chains are different, write them in alphabetical order

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

What is a good leaving group?

A

A stable species removed during a chemical reaction

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

What is the leaving group of acyl chlorides?

What is the by product?

A

Cl-

HCl

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

What is the leaving group of an acid anhydride?

What is the by product?

A

-OCOR

The corresponding carboxylic acid

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

Name the mechanism and reaction name for acylation

A

Nucleophilic addition elimination

Reduction

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

Describe nucleophilic addition elimination

A

Nucleophile attacks the delta positive carbon of the carbonyl group forcing the e- to move from the carbonyl bond to the O making an oxyanion

Carbonyl bond remade causing elimination of the leaving group

Nucleophile loses a H+

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

How are carboxylic acids formed? (3)

A

1) primary alcohols or aldehydes oxidised by acidified potassium dichromate
2) acyl chlorides react with water (nucleophilic addition elimination)
3) acid anhydrides react with water

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

Test for carboxylic acids

What is formed?

A

Add Sodium carbonate and CO2 is evolved and fizzing is seen

Ionic salts - these are soluble in water

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

Name of reaction to form an Ester

What are the reactants?

What is the byproduct?

A

Esterification

Carboxylic acid + alcohol with concentrated H2SO4 (or another strong acid) as a catalyst

Water

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

What is the isomerism linking esters and carboxylic acids?

A

They are functional group isomers

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

How do you name an Ester?

A

The alkyl chain of the alcohol is the prefix

The second part of the name is derived from the carboxylic acid - -oic is replaced with -oate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the 3 ways to form an Ester?

A

Esterification
Acyl Chlorides reacting with alcohols
Acid anhydrides react with alcohols

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the name for the formation of esters from acyl chlorides?

A

Nucleophilic addition elimination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is esterification?

A

Mixing a carboxylic acid and an alcohol in the presence of a concentrated H2SO4 catalyst to form an Ester and water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is a base added after the formation of an Ester from acyl chlorides?

A

To neutralise HCl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Why are acyl chlorides preferred to carboxylic acids in the formation of esters?

A

No acid catalyst required
Purer product
Yield of Ester is higher as acyl chloride reaction is not reversible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the mechanism to form an Ester from alcohols and acid anhydrides?

What is formed?

A

Nucleophilic addition elimination

An Ester and a carboxylic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the most preferable way to form esters?

Why?

A

From acid anhydrides

Acid anhydrides are cheaper
They react less exothermically so it is less dangerous
Acid anhydrides are less vulnerable to hydrolysis
No corrosive HCl is formed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is a major use of ethanoic anhydride?

Why is this used over ethanoyl Chloride ?

A

In aspirin

Ethanoic anhydride is cheaper, less corrosive, less vulnerable to hydrolysis, and less dangerous to use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the method for the re-crystallisation of crude product?

A

Dissolve sample in a minimum amount of hot solvent
Filter hot
Cool filtrate in a beaker placed in an ice bath
Filter sample using a Büchner funnel
Wash thoroughly to remove any SOLUBLE product
Alllow product to dry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Why do you dissolve the sample in a minimum amount of hot solvent when filtering under pressure/ during recrystallisation?

A

To Create a saturated solution and increase the yield

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Why do you filter hot during recrystallising?

A

To prevent recrystallisation whilst filtering and to remove insoluble impurities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Why do you cool the filtrate during recrystallisation?

A

To increase amount of crystals formed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the method to test the melting point of the final product of recrystallisation of a crude product?

A

Use melting point apparatus provided to heat sample gently
Heat slowly close to melting point of aspirin
If aspirin is pure the sample should melt over 1-2 degrees and should have a melting point close to data book value
Impurities will cause melting point to be lower and have a larger range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Describe apparatus for filtering under pressure

A

Wide funnel, with horizontal filter paper, going into sealed Büchner funnel
Arm going off to the side leading to a vacuum pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is hydrolysis?

A

Breaking up a molecule with H2O or another small molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is hydration?

A

Addition of water

41
Q

What is dehydration?

A

Elimination of water

42
Q

What is hydrogenation?

A

Addition of hydrogen

43
Q

What is the reverse of esterification?

Describe

A

The hydrolysis of an Ester

Ester is hydrolysed back to their carboxylic acid and alcohol groups using water and dilute sulphuric acid catalyst

44
Q

The hydrolysis of an Ester is a reversible reaction. How do you make the hydrolysis as complete as possible?

A

Add an excess of water

45
Q

What occurs when an Ester is heated with an alkali?

What are the 2 mains steps to finally form a carboxylic acid?

A

It is hydrolysed to an alcohol and a carboxylate salt

Add NaOH to form carboxylate salt
Add acid (dilute H2SO4) to form a carboxylic acid
46
Q

Why can’t you draw a line between

CH3COO- and Na+?

A

It is an ionic bond (not covalent) so you have to write them next to each other with their charges showing

47
Q

What is a triglyceride?

Where do they occur?

A

A triester of long chain carboxylic acids (fatty acids) and propane-1,2,3-triol

In fats and oils

48
Q

How can triesters be hydrolysed?

A

Using HOT NaOH to form glycerol and the sodium salts of long chain carboxylic acids

49
Q

What can sodium carboxylate salts be used for?

50
Q

Why is glycerol useful and for what?

A

Is has 2 -OH bonds so forms hydrogen bonds very easily in water

Cosmetics, food, wine, glues (to prevent materials drying too fast)

51
Q

How to remember that sodium carboxylate salts make soap?

A

Sibilance: “Sodium SaltS = SoapS”

52
Q

What is a biofuel?

A

A fuel produced from renewable biological sources

53
Q

What does an Ester + CH3OH (methanol) —>?

A

Methylester + alcohol

54
Q

Define biodiesel

A

Liquid fuel consisting of a mixture of methyl esters of long-chain carboxylic acids from vegetable oils

55
Q

What is a possible solution to our reliance on crude oil?

A

Biodiesel- a renewable fuel formed from crops eg rape seed

Rape seed oil is a triglyceride Ester

56
Q

How do you make biodiesel from rape seed oil?

A

React it with methanol (and a strong acid or alkali as a catalyst) to form a mixture of methyl esters

57
Q

Give the key features of bioethanol

A

Raw materials: sugar cane
Made via fermentation
Used as a mixture with petrol for cars
Increasingly available in the UK

58
Q

Give the key features of biodiesel

A

Made from vegetable oil in a reaction with methanol
Used in cars, buses etc as a mixture with diesel
Can be home made and available at some petrol stations

59
Q

How are amides named?

A

With the suffix -anamide

Eg propanamide

60
Q

2 ways to form an amide

A

Acyl chlorides with NH3

Acid anhydrides with NH3

61
Q

What is the functional group of amides?

A

R-C=O
|
NH2

62
Q

Why is an excess of NH3 used in reaction of acyl chlorides with ammonia?

Name the mechanism and conditions for this mechanism

A

To neutralise HCl

Nucleophilic addition elimination

63
Q

Mechanism for acid anhydride with NH3

A

Nucleophilic addition elimination

64
Q

Functional group for N-Substituted Amides

A 
R-C=O
     |
    N-H 
     |
     R
65
Q

How do you name an N-Substituted Amide?

A

Using an N-alkyl prefix to indicate alkyl group attached to N only and the suffix “-anamide” to indicate length of C chain attached to carbonyl

Eg N-propyl ethanomide

66
Q

How to form N-Substituted Amides using amines

A

React an acyl chloride or an acid anhydride with an amine

Nucleophilic addition elimination

67
Q

What is a biofuel?

A

A fuel produced from renewable biological sources

68
Q

What does an Ester + CH3OH (methanol) —>?

A

Methylester + alcohol

69
Q

Define biodiesel

A

Liquid fuel consisting of a mixture of methyl esters of long-chain carboxylic acids from vegetable oils

70
Q

What is a possible solution to our reliance on crude oil?

A

Biodiesel- a renewable fuel formed from crops eg rape seed

Rape seed oil is a triglyceride Ester

71
Q

How do you make biodiesel from rape seed oil?

A

React it with methanol (and a strong acid or alkali as a catalyst) to form a mixture of methyl esters

72
Q

Give the key features of bioethanol

A

Raw materials: sugar cane
Made via fermentation
Used as a mixture with petrol for cars
Increasingly available in the UK

73
Q

Give the key features of biodiesel

A

Made from vegetable oil in a reaction with methanol
Used in cars, buses etc as a mixture with diesel
Can be home made and available at some petrol stations

74
Q

How are amides named?

A

With the suffix -anamide

Eg propanamide

75
Q

2 ways to form an amide

A

Acyl chlorides with NH3

Acid anhydrides with NH3

76
Q

What is the functional group of amides?

A

R-C=O
|
NH2

77
Q

Why is an excess of NH3 used in reaction of acyl chlorides with ammonia?

Name the mechanism and conditions for this mechanism

A

To neutralise HCl

Nucleophilic addition elimination

78
Q

Mechanism for acid anhydride with NH3

A

Nucleophilic addition elimination

79
Q

Functional group for N-Substituted Amides

A 
R-C=O
     |
    N-H 
     |
     R
80
Q

How do you name an N-Substituted Amide?

A

Using an N-alkyl prefix to indicate alkyl group attached to N only and the suffix “-anamide” to indicate length of C chain attached to carbonyl

Eg N-propyl ethanomide

81
Q

How to form N-Substituted Amides using amines

A

React an acyl chloride or an acid anhydride with an amine

Nucleophilic addition elimination

82
Q

What is a biofuel?

A

A fuel produced from renewable biological sources

83
Q

What does an Ester + CH3OH (methanol) —>?

A

Methylester + alcohol

84
Q

Define biodiesel

A

Liquid fuel consisting of a mixture of methyl esters of long-chain carboxylic acids from vegetable oils

85
Q

What is a possible solution to our reliance on crude oil?

A

Biodiesel- a renewable fuel formed from crops eg rape seed

Rape seed oil is a triglyceride Ester

86
Q

How do you make biodiesel from rape seed oil?

A

React it with methanol (and a strong acid or alkali as a catalyst) to form a mixture of methyl esters

87
Q

How do you name an N-Substituted Amide?

A

Using an N-alkyl prefix to indicate alkyl group attached to N only and the suffix “-anamide” to indicate length of C chain attached to carbonyl

Eg N-propyl ethanomide

88
Q

How to form N-Substituted Amides using amines

A

React an acyl chloride or an acid anhydride with an amine

Nucleophilic addition elimination

89
Q

Functional group for N-Substituted Amides

A 
R-C=O
     |
    N-H 
     |
     R
90
Q

Mechanism for acid anhydride with NH3

A

Nucleophilic addition elimination

91
Q

Why is an excess of NH3 used in reaction of acyl chlorides with ammonia?

Name the mechanism and conditions for this mechanism

A

To neutralise HCl

Nucleophilic addition elimination

92
Q

What is the functional group of amides?

A

R-C=O
|
NH2

93
Q

2 ways to form an amide

A

Acyl chlorides with NH3

Acid anhydrides with NH3

94
Q

How are amides named?

A

With the suffix -anamide

Eg propanamide

95
Q

Give the key features of biodiesel

A

Made from vegetable oil in a reaction with methanol
Used in cars, buses etc as a mixture with diesel
Can be home made and available at some petrol stations

96
Q

Give the key features of bioethanol

A

Raw materials: sugar cane
Made via fermentation
Used as a mixture with petrol for cars
Increasingly available in the UK

97
Q

What is the functional group of acid anhydrides?

A 
R
 |
C=O
 |
O
 |
C=O
 |
R
98
Q

What is the functional group of esters?

A 
R 
 |
C=O
 |
OR

Organic Chemistry (12 decks)

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