Brainscape's Knowledge GenomeTM

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


See full index

AQA A Level Chemistry > Carboxylic Acids and its Derivatives > Flashcards

Carboxylic Acids and its Derivatives Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

Functional group of carboxylic acids

A

RCOOH.
C=O and C-OH

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

Why are the intermolecular forces between carboxylic acid molecules relatively strong

A

Due to the presence of two polar groups, C=O and C-OH

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

Why do carboxylic acids have a higher boiling point than alcohols

A

Each carboxylic acid molecule can form 2 hydrogen bonds but each alcohol molecule can only form one. More energy is needed to break the hydrogen bonds between carboxylic acid molecules.

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

Why are some carboxylic acid molecules soluble in water

A

They can form hydrogen bonds with water molecules because it has a polar -COOH group. The -COOH group can form hydrogen bonds with water molecules. ONLY CARBOXYLIC ACIDS 1 to 4 are soluble

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

Why is benzoic acid only slightly soluble in water

A

The -COOH group can form hydrogen bonds with water molecules. However, it is only slightly soluble because the benzene ring is non-polar

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

Describe the reaction, conditions and reagents needed to go from a nitrile to a carboxylic acid

A

Reaction : Acid hydrolysis
Reagent : Dilute HCl
Conditions : Heat under reflux

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

nitrile + water + hydrochloric acid =

A

Carboxylic acid + ammonium chloride

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

Are carboxylic acids strong or weak acids

A

Weak. They only partially dissociate in solution

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

How are carboxylate salts produced

A

Acid-base reactions

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

ethanoic acid + NaOH ——–>

A

CH3-COO-Na+ + H2O

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

What are the reagents and conditions for acid-base reactions in the production of carboxylate salts

A

Reagent : AQEUOUS sodium carbonate/hydroxide
Conditions : Room temperature

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

propanoic acid + sodium carbonate =

A

sodium propanoate + water + carbon dioxide

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

What is the test for the -COOH group

A

Add aqueous sodium carbonate to the compound. Bubble the gas produced into limewater. Fizzing/effervescence is observed. The colourless gas (CO2) turns limewater cloudy

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

Describe esterification

A

When a carboxylic acid is heater under reflux with an alcohol in the presence of an acid catalyst such as conc sulfuric acid, an ester is formed

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

What do carboxylic acids do to carbonates even though they are weak acids

A

They liberate the CO2 from carbonates.

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

What type of reaction is it when esters are formed from the reaction between carboxylic acids and alcohols

A

Reversible reaction

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

Why is the yield of esters low when produced from reacting carboxylic acids and alcohols

A

It is a reversible reaction and results in an equilibrium therefore low yield

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

Reagents and conditions for esterification

A

Reagents: Alcohol and concentrated sulfuric acid
Conditions : Heat under reflux

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

How to draw esters

A

Break the -OH off the carboxylic acid
Break the H off the -OH on the alcohol
Connect the O of the alcohol to the main C of the carboxylic acid.

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

How to name esters

A

The alcohol part first and then the carboxylic acid part.
e,g, propyl ethanoate

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

Functions of concentrated sulphuric acid in esterification

A

Acts as the catalyst for the reaction
Absorbs the water formed, driving the equilibrium to the right and increasing the yield of the ester

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

Functional group for esters

A

-COOR
There is a C=O and and -OR attached to the same carbon

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

Common uses of esters

A

In solvents
Plasticisers
Perfumes
Food flavourings

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

Main use of polyesters

A

Clothing

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

How can esters be produced by acyl chlorides

A

When acyl chloride reacts with an alcohol at room temperature an ester and HCl is formed.
This reaction is called Nucleophilic addition-elimination

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

What is the advantage of making esters by reacting an acyl chloride with alcohol

A

The reaction goes to completion giving a higher yield of the ester

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

What is produced in the acid hydrolysis of esters

A

A carboxylic acid and an alcohol

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

Conditions and reagents for acid hydrolysis of esters

A

Conditions : Heat under reflux
Reagent: dilute HCl/H2SO4 - acts as catalyst

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

ester + water ———->
<———-

A

Carboxylic acid + alcohol

30
Q

Describe what happens in acid hydrolysis of esters

A

Ester is heated with dilute HCl
C-O bond in ester is broken using water
Carboxylic acid and alcohol produced

31
Q

Describe what happens in alkaline hydrolysis of water

A

Ester is heated with aqueous NaOH/KOH
A carboxylate salt and an alcohol are formed

32
Q

Advantages of alkaline hydrolysis of esters

A

Reaction goes to completion giving a higher yield
Products are easier to separate. Alcohol formed can be distilled off.

33
Q

ester + NaOH/base ——->

A

carboxylate salt + alcohol

34
Q

How are soaps made

A

By the alkaline hydrolysis of fats and oils. Saponification
The sodium salts of the carboxylic acid and the alcohol, glycerol, are formed

35
Q

Trigylceride + NaOH =

A

Soap + glycerol

36
Q

What is the chemical name for glycerol

A

propane-1,2,3-triol

37
Q

What are the esters of glycerol / propane-1,2,3-triol

A

Vegetable oils and animal fats

38
Q

How do vegetable oils and animals fats produce soaps and glycerol

A

Through alkaline hydrolysis

39
Q

What is biodiesal

A

A mixture of methyl esters of long-chain carboxylic acids

40
Q

How is biodiesel produced

A

By reaction vegetable oils with methanol in the presence of a catalyst

41
Q

Describe esterification of acid anhydrides with alcohols

A

The bottom part of the acid anhydride which looks like a carboxylic acid (RCOO) breaks off. The H of the alcohol also breaks off.

This forms an ester and carboxylic acid

42
Q

What is formed when a carboxylic acid is heated under reflux with an alcohol in the presence of an acid catalyst

A

An ester

43
Q

How can we tell if an ester is formed

A

A fruity smell

44
Q

How would you convert ethanoic acid into propyl ethanoate

A

Heat under reflux ethanoic acid with propan-1-ol and concentrated sulfuric acid as the catalyst

45
Q

Do esters have hydrogen bonding

A

Not between esters but can form hydrogen bonds with water

46
Q

Explain why the ester methyl methanoate has a much lower boiling point than its isomer ethanoic acid and why ethanoic acid has a lower boiling point than propanoic acid.

A

There are hydrogen bonds between molecules of ethanoic acid because it has a polar -COOH group. The ester cannot form hydrogen bonds and has weaker permanent dipole-dipole interactions and Van der Waals forces between its molecules. Less energy is needed to break the weaker intermolecular forces in the ester.

Ethanoic acid has fewer electrosn than propanoic acid, so the Van der Waals forces between molecules of ethanoic acid are weaker. Less energy is needed to break the weaker intermolecular forces in ethanoic acid.

47
Q

What are esters isomeric with

A

Carboxylic acids

48
Q

Suggest 3 hazards that could occur when using propanoyl chloride to make the ester and describe how you would minimise this risk

A

Propanoyl chloride is toxic, use a fume cupboard
Hydrogen chloride is formed which is toxic, use a fume cupboard
Propanoyl chloride is corrosive, wear gloves when handling

49
Q

What happens in the hydrolysis of esters

A

The C-O bond in ester is broken using water

50
Q

Typical acid hydrolysis of esters reaction

A

Ester + water ⇌ Carboxylic acid + alcohol
Heated with dilute HCL/ dilute H2SO4

51
Q

Condition for acid hydrolysis of esters

A

Heat under reflux

52
Q

Typical alkaline hydrolysis of esters reaction

A

Ester + NaOH/KOH ——-> Carboxylate salt + alcohol

53
Q

Advantages of alkaline hydrolysis of esters

A

Reaction goes to completion giving a higher yield
The products are easier to separate. The alcohol can be distilled off

54
Q

What happens in trans-esterification

A

A trigylceride/ tri-ester reacts with an alcohol to form ester + glycerol
The ester is then used as biodiesal

55
Q

Triglyceride + NaOH ——–>

A

soap + glycerol

56
Q

Triglyceride + alcohol

A

biodiesal + glycerol

57
Q

Functional group of acyl chlorides

A

COCl.
The C=O bond is a double bond

58
Q

How to name acyl chlorides

A

-oyl chloride

59
Q

Name CH3COCl

A

Ethanoyl chloride

60
Q

Why do acyl chlorides get attacked by nucleophiles

A

The carbonyl carbon in an acyl chloride is very delta positive because the chlorine atom and oxygen is highly electronegative.

61
Q

What are typical reaction of acyl chlorides called

A

Nucleophilic addition-elimination reactions

62
Q

Hazards when using acyl chlorides and how to minimise

A

They are toxic so use a fume cupboard
They are corrosive so wear gloves when handling

63
Q

Acyl chloride + water =

A

Carboxylic acid + HCl
white fumes of hydrogen chloride gas seen

64
Q

Acyl chloride + alcohol/phenols =

A

Ester + HCl

65
Q

Acyl chloride + concentrated ammonia

A

amide + NH4Cl

66
Q

Acyl chloride + primary amines =

A

N-substituted amide + HCl

67
Q

Conditions for all acyl chloride reactions

A

Room temperature

68
Q

How do acid anhydrides react

A

In the same way as acyl chlorides but not as vigorously

69
Q

Conditions for acid anhydrides reactions

A

Heat under reflux

70
Q

What do acid anhydrides look like

A

CH3C(O)OCH3C(O)
2 C=O bonds

like a reflection about the central oxygen atom

AQA A Level Chemistry (27 decks)

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