Unit 3.4.5 - Carbonyl groups Flashcards
1
Q
What functional group do aldehydes and ketones share?
A
=O
2
Q
What is the difference between aldehydes and ketones?
A
Aldehydes have the =O at the end of the carbon chain Ketones have the =O in the middle of the carbon chain
3
Q
How can aldehydes be made?
A
By oxidising primary alcohols
4
Q
How can ketones be made?
A
By oxidising secondary alcohols
5
Q
What suffix is used to name aldehydes?
A
-al
6
Q
What suffix is used to name ketones?
A
-one
7
Q
Other than the suffix used what is the difference between naming aldehydes and ketones?
A
With ketones you have to say the number of the carbon the functional group comes off
8
Q
What can you oxidise an aldehyde too?
A
Carboxylic acid
9
Q
What can you oxidise a ketone too?
A
It can’t be oxidised
10
Q
Name three tests to distinguish between aldehydes and ketones.
A
You heat with …… Tollen’s reagent, Benedict’s solution or Fehling’s solution
11
Q
What do all the tests for distinguishing between aldehydes and ketones work on?
A
The fact an aldehyde can be oxidised but a ketone can’t
12
Q
What is Tollen’s reagent?
A
Colourless solution of silver nitrate dissolved in aqueous ammonia
13
Q
What are the results when a ketone and aldehyde is mixed with Tollen’s reagent?
A
Ketone - no visible change Aldehyde - silver mirror forms
14
Q
What is the equation for when diamine silver ions are reduced, when they are used as Tollen’s reagent?
A
[Ag(NH₃)₂]⁺ + e⁻ → Ag + 2NH₃
15
Q
What is Fehling’s solution?
A
Blue solution of a complexed copper (II) ions dissolved in sodium hydroxide
16
Q
What are the results when a ketone and aldehyde is mixed with Fehling’s solution?
A
Ketone - no visible change Aldehyde - brick red precipitate
17
Q
What is the equation for when copper(II) ions are reduced, when used as Fehling’s solution?
A
Cu²⁺ + e⁻ → Cu⁺
18
Q
What is Fehling’s solution similar too?
A
Benedict’s solution
19
Q
What are the results when a ketone and aldehyde is mixed with Benedict’s solution?
A
Ketone - no visible change Aldehyde - brick red precipitate
20
Q
What can you reduce an aldehyde too?
A
Primary alcohol
21
Q
What can you reduce a ketone too?
A
Secondary alcohol
22
Q
Give an example of a reducing agent used to reduce a aldehyde to a primary alcohol.
A
Sodium borohydride - NaBH₄
23
Q
What is usually used to represent a reducing agent?
A
[H]
24
Q
What is the mechanism called for when an aldehyde is reduced to a primary alcohol?
A
Nucleophilic addition
25
What from the reducing agent acts as a nucleophile for the mechanisms of an aldehyde being reduced to a primary alcohol
H⁻
26
What are the five steps in the mechanism for the reaction between an aldehyde and H⁻?
1.) The C=O bond is polar so the carbon is slightly positive and attracts the negative lone pair of electrons on the H⁻ ion 2.) The H⁻ ion attacks the slightly positive carbon and donates its pair of electrons forming a bond with the carbon 3.) As the carbon can only have four bonds this causes one of the carbon-oxygen bonds to break, forcing a lone pair of electrons from the C=O double bond onto the oxygen 4.) The oxygen then donates its lone pair of electrons to a H⁺ ion (which has come from from or a weak acid) 5.) And so a primary alcohol is produced
27
How can you produce hydroxynitriles?
By reacting aldehyde or ketones with hydrogen cyanide
28
What is produced when you react aldehydes or ketones with hydrogen cyanide?
Hydroxynitriles
29
What are hydroxynitriles?
Molecules which contain a hydroxyl group (OH) and a nitrile group (CN)
30
How do you name hydroxynitriles?
The nitrile group takes priority and so you name that with the suffix -nitrile, the carbon in the nitrile group is then carbon-1, you then name the hydroxyl group with the prefix hydroxyl- along with the number of the carbon atom it comes off
31
What is the mechanism called for when an aldehyde or ketone reacts with hydrogen cyanide to produce a hydroxylnitrile?
Nucleophilic addition
32
What are the six steps in the mechanism for when hydrogen cyanide reacts with an aldehyde or ketone?
1.) HCN is a weak acid so partially dissociates in water to form H⁺ ions and CN⁻ ions 2.) The C=O bond is polar so the carbon is slightly positive and attracts the negative lone pair of electrons on the CN⁻ ion 3.) The CN⁻ ion attacks the slightly positive carbon and donates its pair of electrons forming a bond with the carbon 4.) As the carbon can only have four bonds this causes one of the carbon-oxygen bonds to break, forcing a lone pair of electrons from the C=O double bond onto the oxygen 5.) The oxygen then donates its lone pair of electrons to a H⁺ ion 6.) A hydroxylnitrile is produced
33
What is often used instead of HCN? and why?
Acidified KCN HCN is extremely toxic and so KCN is used to reduce the risk and it is also easier to store Acidified to provide the H⁺ ions for the reaction
34
How should you heat aldehydes and ketones and why?
In a water both because they are very flammable
35
What functional group do carboxylic acids contain
-COOH
36
What suffix is used to name carboxylic acids?
-oic acid
37
What type of acids are carboxylic acids?
Weak
38
Why are carboxylic acids only weak acids?
They only partially dissociate into carboxylate ions and H⁺ ions
39
What do carboxylic acids react with carbonates or hydrogen carbonates to form?
A salt, carbon dioxide and water
40
What is the symbol for a carbonate ion?
CO₃²⁻
41
What is the symbol for a hydrogen carbonate ions?
HCO₃⁻
42
What can you react with a carboxylic acid to form a salt, carbon dioxide and water?
Carbonates or hydrogen carbonates
43
What is the equation for ethanoic acid reacting with sodium carbonate?
2CH₃COOH + Na₂CO₃ → 2CH₃COONa + H₂O + CO₂
44
What is the equation for ethnic acid reacting with sodium hydrogen carbonate?
CH₃COOH + NaHCO₃ → CH₃COONa + H₂O + CO₂
45
What is CH₃COONa?
Sodium ethanoate
46
How can you produce an ester from a carboxylic acid?
Heat in with an alcohol with a concentrated acid catalyst
47
What is produced when you heat a carboxylic acid with an alcohol and a concentrated acid catalyst?
Ester
48
How are esters named?
You name the first part with the alkyl group that came from the alcohol and then add the name of the carboxylic acid swapping the -oic acid for -oate
49
How do you name other functional group on esters?
Away from the C-O-C bond with both of these carbons being carbon-1
50
Name four uses of esters.
Perfumes, flavourings, solvents, plasticisers
51
Why are esters used in perfumes and as flavourings?
They can have a pleasant sweet smell
52
Why are esters used as solvents?
They are polar liquids so lots of polar organic compounds with dissolve in them, they also have a low boiling point so they an evaporate easily from the mixture
53
How are esters used as plasticisers?
They are added to plastics during polymerisation to make the plastics more flexible
54
What is hydrolysis?
When a substance is split up using water
55
What is the name for the reaction between an alcohol and carboxylic acid?
Esterification
56
As hydrolysis of an ester is often slow what is added to speed up the reaction?
An acid or alkali
57
What are the two types of hydrolysis called?
Acid hydrolysis and base hydrolysis
58
What is acid hydrolysis the reverse of?
Esterification
59
How do you carry out acid hydrolysis?
Reflux an ester with dilute acid
60
What does acid hydrolysis produce?
A carboxylic acid and alcohol
61
Why do you need a lot of water for acid hydrolysis?
The reactions are reversible so you need lots of water to push the equilibrium over to the right so you get more products
62
How do you carry out base hydrolysis?
Reflux an ester with a dilute alkali
63
What does base hydrolysis produce?
A carboxylate ion and alcohol
64
Name a common naturally occurring ester?
Fats and oil
65
What are fats and oils esters of?
Glycerol and fatty acids
66
What are fatty acids?
Long chain carboxylic acids
67
What is the actual name of glycerol?
propan-1,2,3-triol
68
How many fatty acids bond to glycerol to make fats and oils?
3
69
Where do most of the properties of fats and oils come from? And why?
The long chain fatty acid as it is what makes up most of the fat or oil
70
What are two types of fatty acids?
Saturated or unsaturated
71
What is meant by saturated?
No double bonds
72
What is meant by unsaturated?
Double bonds
73
What type of hydrocarbon (fatty acid) tail to fats have?
Saturated
74
Why are fats solid at room temperature?
They can fit closely together increasing the van der Waals forces between them, therefore a higher temperature is needed to overcome the forces and melt them so they are solid at room temperature
75
What type of hydrocarbon (fatty acid) tail to oils have?
Unsaturated
76
What is the difference between fats and oils?
Oils are unsaturated and so contain double bonds where as fats are unsaturated so only contain single bonds
77
Why are oils liquid at room temperature?
The double bonds means the chains are bent and so they don't pack well together, decreasing the effect of the van der Waals forces, meaning they are easier to overcome and they melt at lower temperatures and so are liquid at room temperature
78
What type of hydrolysis can be used to used to split fats or oils?
Base hydrolysis
79
What do you heat fats and oils with to split them?
Sodium hydroxide
80
What is produced when you heat a fat or oil with sodium hydroxide?
Alcohol and a sodium salt (the carboxylate ion reacts with the Na⁺)
81
What is a use of sodium salt?
As salt
82
How can you convert a sodium salt back into a long chain carboxylic acid?
By adding an acid such as HCl, as the H⁺ ions displace the Na⁺ ions in the salt forming a carboxylic acid
83
What is biodiesel a mixture of?
Methyl esters of long chain carboxylic acids
84
What do you have to do with vegetable oils to produce biodiesel?
React them with methanol using a strong alkali as as catalyst, to produce a mixture of methyl esters which is the biodiesel and glycerol
85
What is biodiesel thought to be carbon neutral?
When the crops grow they absorb the same amount of CO₂ as they produce when they are burnt
86
Why isn't biodiesel carbon neutral?
Energy is used to make fertiliser to grow the crops, during planting, during harvesting and when converting the crop into oil, this energy comes from burning fossil fuels which release carbon dioxide
87
What functional group do acyl chlorides have?
-COCl
88
What is another name for acyl chlorides?
Acid chlorides
89
What suffix is used to name acyl chlorides?
-oyl chloride
90
Name four things acyl chlorides react with?
Cold water, alcohols, ammonia and amines
91
What is a common product when acyl chlorides are reacted with cold water, alcohols, ammonia and amines ?
Hydrogen chloride
92
How do you know hydrogen chloride has been produced?
You will see misty fumes
93
What is produced when you react an acyl chloride with cold water?
Carboxylic acid and hydrogen chloride
94
What is produced when you react an acyl chloride with an alcohol?
Ester and hydrogen chloride
95
What is produced when you react an acyl chloride with ammonia?
Amide and hydrogen chloride
96
What is produced when you react an acyl chloride with an amine?
N-substituted amide and hydrogen chloride
97
What do you react an acyl chloride with to produce an ester?
Alcohols
98
What do you react an acyl chloride with to produce a carboxylic acid?
Cold water
99
What do you react an acyl chloride with to produce an amide?
Ammonia
100
What do you react an acyl chloride with to produce an N- substituted amide?
Amines
101
What is the name of the mechanism for the reaction between acyl chlorides and cold water, alcohols, ammonia or amines ?
Nucleophilic addition-elimination
102
What are the two general steps during acyl chloride nucleophilic addition-elimination reactions?
1.) The nucleophile adds onto the acyl chloride displacing the Cl⁻ ions 2.) The Cl⁻ ion steals a hydrogen ion from the nucleophile to eliminate HCl
103
What are acid anhydrides?
Two identical carboxylic acids joined together via an oxygen
104
How do you name acid anhydrides?
Take away the acid from the carboxylic acid it is made from and add anhydride
105
What is the difference between the reactions of acyl chlorides and acid anhydrides?
Acid anhydrides react less vigorously and a carboxylic acid is formed instead of HCl
106
What is produced when you react an acid anhydride with cold water?
Two of the same carboxylic acids
107
What is produced when you react an acid anhydride with an alcohol?
Ester and carboxylic acid
108
What is produced when you react an acid anhydride with ammonia?
Amide and carboxylic acid
109
What is produced when you react an acid anhydride with an amine?
N substituted amide and carboxylic acid
110
What do you react an acid anhydride with to produce an N- substituted amide?
Amine
111
What do you react an acid anhydride with to produce an amide?
Ammonia
112
What do you react an acid anhydride with to produce an ester?
Alcohol
113
What do you react an acid anhydride with to produce an two carboxylic acids?
Cold water
114
What else is released when you turn a carboxylic acid into an acid anhydride?
Water
115
Name an ester used as a drug?
Aspirin
116
How is aspirin made?
By reacting salicylic acid with either ethanoic anhydride or ethanoyl chloride
117
What is more commonly used to make aspirin: ethanoic anhydride or ethanol chloride? And why?
Ethanoic anhydride is used more often because it is cheaper and safer because it is less corrosive, reacts more slowly with water and doesn't produce dangerous hydrogen chloride fumes
118
What is the functional group of amides?
-CONH₂
119
Why do amides behave differently from amines?
The carbonyl group pulls electron density away from the NH₂ group so they behave differently
120
What suffix is used to name amides?
-amide
121
What are n-substituted amides?
Where one of the hydrogens attached to the nitrogen has been substituted for an alkyl group
122
What to do you name N-substitued amides?
N-whatever alkyl group have been added to the nitrogen
123
Draw the general structure of aldehydes and ketones.
124
Draw the general equation for for the oxidation of an aldehyde.
125
Draw the general equation for reducing an aldehyde.
126
Draw the generla equation for reducing a ketone.
127
Draw the general structure of a hydroxynitrile.
128
Draw the general structure of a carboxylic acid.
129
Draw the equation for how a carboxylic acid pratially dissociates.
130
Draw the general reaction between an alcohol and a carboxylic acid.
131
Draw the general equation for acid hydrolysis.
132
Draw the general equation for base hydrolysis.
133
Draw the general strcuture of a fat or oil.
134
Draw the rest of this reaction.
135
Draw the general equation for the foramtion of biodiesel.
136
Draw the reaction between ethanoic anhydride and ammonia.
137
Draw the reaction between ethanoic anhydride and methylamine.
138
Draw the general structure of an amide.
139
Draw the reaction between ethanoic acid and methanol.
140
Draw the reaction between ethanoic anhydride and water.
141
Draw the reaction between ethanoyl chloride and methylamine.
142
Draw the reaction between ethanoyl chloride and ammonia.
143
Draw the reaction between ethanoyl chloride and methanol.
144
Draw the reaction between ethanoyl chloride and water.
