1
Q
What is a chiral centre?
A
A carbon atom with four different groups bonded around it, resulting in no line of symmetry
The chiral centre is commonly indicated using * next to the asymmetric carbon.
2
Q
What is optical isomerism?
A
A type of stereoisomerism where molecules have the same molecular formula but a different spatial arrangement of atoms
The presence of a chiral centre leads to two possible isomers that are mirror images of each other.
3
Q
True or false: The presence of a chiral centre leads to two possible isomers that are mirror images of each other.
A
TRUE
These mirror image isomers are known as optical isomers.
4
Q
What are the two different isomers of 2-hydroxypropanoic acid called?
A
enantiomers
Enantiomers are unique due to their effect on plane polarised light.
5
Q
What effect do enantiomers have on plane polarised light?
A
- Cause rotation of plane polarised light in opposite directions
This property distinguishes enantiomers from one another.
6
Q
What is a racemate?
A
A pair of enantiomers produced in a 1:1 ratio
A racemate is formed when optical isomers are produced, resulting in an optically inactive mixture.
7
Q
What effect does a racemic mixture have on polarized light?
A
The overall effect is zero due to cancellation
Each enantiomer rotates polarized light in opposite directions.
8
Q
How are the two isomers in a racemic mixture produced?
A
By a nucleophilic addition reaction
This reaction allows for the formation of equal quantities of each isomer.
9
Q
What type of intermediate is involved in SN1 reactions?
A
Planar carbocation intermediate
This allows the incoming nucleophile to attack from either face of the compound.
10
Q
True or false: The product of SN1 reactions is always a racemic mixture.
A
TRUE
The planar nature of the carbocation allows for equal attack from both sides.
11
Q
What type of reaction mechanism occurs in Sy2 reactions?
A
Single step
In Sy2 reactions, the nucleophile attacks while the leaving group is removed, resulting in a single direction of attack.
12
Q
What is produced in S2 reactions?
A
A single enantiomer
The mechanism of S2 reactions leads to the formation of only one enantiomer due to the nature of the nucleophile’s attack.
13
Q
In nucleophilic addition reactions, nucleophiles attack a molecule with a _______ group.
A
carbonyl
The attack can occur from above or below the planar carbon-oxygen double bond.
14
Q
What type of products are formed in nucleophilic addition reactions?
A
Mirror images
These products are optical isomers due to the nature of the attack on the carbonyl group.
15
Q
Nucleophilic addition reactions provide evidence for how _______ activity arises in molecules.
A
optical
The formation of optical isomers demonstrates the concept of optical activity.
16
Q
What is a carbonyl compound?
A
An organic compound containing a carbonyl group, C=O
This gives them the functional group -CO.
17
Q
Name the most common carbonyl compounds.
A
- Aldehydes
- Ketones
These compounds are characterized by the presence of a carbonyl group.
18
Q
How do carbonyl compounds interact with water?
A
They can form hydrogen bonds with water
A hydrogen bond forms between a lone electron pair on the oxygen atom and a d+ region on a hydrogen atom.
19
Q
True or false: Aldehydes and ketones can form hydrogen bonds between their own molecules.
A
FALSE
Aldehydes and ketones do not have a d+ hydrogen atom, so they do not form hydrogen bonds between molecules.
20
Q
What type of intermolecular force exists between aldehyde and ketone molecules?
A
Van der Waals forces
This is the only type of intermolecular force present between their molecules.
21
Q
Aldehydes are produced from the initial oxidation and distillation of _______.
A
primary alcohols
This process leads to the formation of aldehydes.
22
Q
Where is the carbonyl group located in aldehydes?
A
At the end of the carbon chain
Aldehydes have the functional group -CHO.
23
Q
Aldehydes can be oxidised further to produce carboxylic acids in the presence of what reagent?
A
Acidified potassium dichromate(VI)
This reaction demonstrates the oxidation of aldehydes.
24
Q
What is the functional group that characterizes ketones?
A
-C=O (carbonyl group)
Ketones are produced from the oxidation of secondary alcohols.
25
Ketones have a carbonyl group on a carbon atom that is attached to how many other carbon atoms?
Two
## Footnote
This structural characteristic differentiates ketones from aldehydes.
26
Ketones are produced from the oxidation of **secondary alcohols** using what reagent?
Acidified potassium dichromate(VI)
## Footnote
This process is essential in organic chemistry for synthesizing ketones.
27
What types of alcohols can be **oxidised** to produce various products?
* Primary alcohols
* Secondary alcohols
## Footnote
Tertiary alcohols are not easily oxidised.
28
Primary alcohols can be heated in the presence of **acidified potassium dichromate(VI)** to produce _______.
aldehydes
## Footnote
This process involves distillation.
29
When heated under reflux, primary alcohols will be oxidised further to produce _______.
carboxylic acids
## Footnote
This indicates a further oxidation process.
30
True or false: **Tertiary alcohols** are easily oxidised.
FALSE
## Footnote
Tertiary alcohols do not undergo oxidation easily.
31
What can **secondary alcohols** be oxidised to when heated in the presence of acidified potassium dichromate(VI)?
ketones
## Footnote
This reaction involves the transformation of secondary alcohols into ketones under specific conditions.
32
What is **Potassium Dichromate(VI)** used for?
As an oxidising agent in the oxidation of alcohols
## Footnote
As the alcohol is oxidised, potassium dichromate(VI) is reduced, indicated by a color change from orange to green.
33
What color change indicates that alcohol has undergone oxidation when using **Potassium Dichromate(VI)**?
From orange to green
## Footnote
This color change signifies the reduction of potassium dichromate(VI) as alcohol is oxidised.
34
What reagents are used to test for **Aldehydes**?
* Tollen's reagent
* Fehling's solution
## Footnote
Both reagents produce a positive result if aldehydes are present.
35
True or false: **Ketones** will give a positive result with Tollen's reagent.
FALSE
## Footnote
Ketones do not produce a positive result with Tollen's reagent or Fehling's solution.
36
What happens when **Fehling's solution** is added to an aldehyde and gently warmed?
A red precipitate will form
## Footnote
This indicates the presence of an aldehyde; if a ketone is present, the solution remains blue.
37
What is observed when **Tollen's reagent** is used to test for aldehydes?
A layer of silver will form on the walls of the test tube
## Footnote
If a ketone is present, the solution remains colourless.
38
What is the **reducing agent** used in the reduction reactions to produce carbonyl compounds from alcohols?
lithium tetrahydridoaluminate (LiAlH4)
## Footnote
LiAlH4 is also known as lithium aluminium hydride.
39
True or false: The reaction involving lithium aluminium hydride (LiAlH4) is carried out in a solvent of **dry ether**.
TRUE
## Footnote
This is necessary because LiAlH4 reacts violently with water and alcohols.
40
In the reduction reactions, what does the reducing agent LiAlH4 provide as a nucleophile?
H: (hydride ion)
## Footnote
The hydride ion acts as a nucleophile in the nucleophilic addition reaction.
41
What is formed first in the reduction reaction before adding a dilute acid?
a salt
## Footnote
The salt is formed before the dilute acid is added to release the alcohol.
42
Fill in the blank: The reducing agent can be represented by _______ in the chemical equation.
[H]
## Footnote
This notation indicates the presence of the hydride ion in the reaction.
43
What type of reaction is exemplified by the reduction of carbonyl compounds from alcohols?
nucleophilic addition
## Footnote
This type of reaction involves the addition of a nucleophile to a carbonyl compound.
44
What type of reaction involves the **:CN nucleophile** in chemical synthesis?
Nucleophilic addition reactions
## Footnote
This reaction causes the carbon chain to be extended by one carbon atom.
45
The product of the nucleophilic addition reaction with the :CN nucleophile is known as a _______.
hydroxynitrile
## Footnote
Hydroxynitriles are important in various chemical synthesis processes.
46
In the mechanism of nucleophilic addition, what is the first step involving the **C=O** bond?
Formation of a tetrahedral intermediate
## Footnote
This step is crucial for the addition of the nucleophile.
47
Fill in the blank: The nucleophilic addition reaction with :CN leads to the extension of the carbon chain by _______.
one carbon atom
## Footnote
This is significant in organic synthesis.
48
What type of reaction involves the **:CN nucleophile** in chemical synthesis?
Nucleophilic addition reactions
## Footnote
This reaction causes the carbon chain to be extended by one carbon atom.
49
The product of the nucleophilic addition reaction with the :CN nucleophile is known as a _______.
hydroxynitrile
## Footnote
Hydroxynitriles are important in various chemical synthesis processes.
50
In the mechanism of nucleophilic addition, what is the first step involving the **C=O** bond?
Formation of a tetrahedral intermediate
## Footnote
This step is crucial for the addition of the nucleophile.
51
Fill in the blank: The nucleophilic addition reaction with :CN leads to the extension of the carbon chain by _______.
one carbon atom
## Footnote
This is significant in organic synthesis.
52
What is often used as the **reagent** to provide the nucleophile instead of HCN?
KCN (potassium cyanide)
## Footnote
HCN is hard to store and is a toxic gas which reacts to produce dangerous byproducts.
53
Hydroxynitriles commonly contain a **chiral carbon centre**, leading to the production of what?
Optical isomers
## Footnote
The :CN- nucleophile can attack from either above or below the planar double bond.
54
What test is used to identify **CH3CO** groups?
Iodoform test
## Footnote
This test can identify aldehydes and ketones.
55
What indicates a **positive result** in the iodoform test?
Formation of a pale yellow precipitate (triiodomethane)
## Footnote
Iodine solution is added to the unknown sample, followed by sodium hydroxide.
56
Which compounds will give a positive result in the iodoform test?
* Aldehydes
* Ketones
## Footnote
Both types of compounds can be identified using this test.
57
What is the **2,4-DNPH test** used for?
Qualitative test for the carbonyl functional group
## Footnote
It reacts with aldehydes and ketones to form a precipitate.
58
What color precipitate forms when aldehydes and ketones react with **2,4-DNPH**?
* Yellow
* Orange
* Reddish-orange
## Footnote
The exact color depends on the identity of the compound.
59
True or false: **Alcohols** produce a precipitate when reacted with 2,4-DNPH.
FALSE
## Footnote
Alcohols and other molecules without carbonyl groups do not produce a precipitate.
60
**Carbonyl compounds** have what characteristic regarding their melting points?
Sharp melting points, melting over a narrow range of temperatures
## Footnote
This property allows for experimental determination and comparison with databook values for identification.
61
What reagent is used to identify specific **aldehydes/ketones** through melting point data?
2,4-DNPH
## Footnote
The addition of 2,4-DNPH to the compound leads to the formation of a precipitate.
62
What is the process used to purify the solid formed after adding 2,4-DNPH?
Recrystallisation
## Footnote
This process allows for the determination of the melting point of the pure crystals.
63
After recrystallisation, the melting point of the pure crystals can be compared with the melting points of __________.
2,4-dinitrophenylhydrazones of all the common aldehydes and ketones
## Footnote
This comparison aids in the identification of the original compound.
64
What is the **functional group** that identifies carboxylic acids?
-COOH
## Footnote
This group contains a carbonyl group (C=O) and an -OH acid group.
65
What suffix is used when **naming carboxylic acids**?
-anoic acid
## Footnote
For example, a carboxylic acid with four carbon atoms is called butanoic acid.
66
How can carboxylic acids be prepared from primary alcohols or aldehydes?
By oxidation under reflux
## Footnote
Acidified potassium dichromate(VI) is commonly used as the oxidising agent.
67
What is another method for producing carboxylic acids?
Hydrolysis of nitrile compounds
## Footnote
This method also leads to the formation of carboxylic acids.
conditions: Dilute HCl heat under reflux
68
What property of carboxylic acids allows them to form hydrogen bonds with each other?
The -COOH functional group
## Footnote
This property contributes to their solubility in water.
69
As the **chain length** of carboxylic acids increases, what happens to their solubility in water?
Decreases
## Footnote
Longer chains contain CH₃ groups that do not form hydrogen bonds with water.
70
**Carboxylic acids** can form hydrogen bonds between molecules due to which parts of their functional group?
* C=O
* O-H
## Footnote
This ability to form hydrogen bonds contributes to their higher boiling and melting points compared to alcohols, aldehydes, and ketones.
71
True or false: The boiling and melting points of **carboxylic acids** are lower than those of alcohols, aldehydes, and ketones.
FALSE
## Footnote
Carboxylic acids have higher boiling and melting points due to hydrogen bonding.
72
What is the effect of **hydrogen bonding** on the boiling and melting points of carboxylic acids?
Higher boiling and melting points
## Footnote
This is due to the strong intermolecular forces created by hydrogen bonds.
73
Fill in the blank: Carboxylic acids have higher boiling and melting points than alcohols, aldehydes, and ketones because they can form _______.
hydrogen bonds
## Footnote
Hydrogen bonding occurs between the C=O and O-H parts of the functional group.
74
What reducing agent is used to produce **primary alcohols** from carboxylic acids?
Lithium tetrahydridoaluminate (LiAlH4)
## Footnote
This is a very reactive compound that reacts violently with water and alcohols.
75
The reaction to produce primary alcohols from carboxylic acids is an example of a **________** reaction.
nucleophilic addition
## Footnote
The reaction is carried out in a solvent of dry ether.
76
In the reduction of carboxylic acids, what does the reducing agent LiAlH4 provide as a nucleophile?
H: nucleophile
## Footnote
The reducing agent can be represented by [H] in the chemical equation.
77
Carboxylic acids are first reduced to **________** during the reduction process.
aldehydes
## Footnote
Aldehydes cannot be isolated as they are more reactive than carboxylic acids.
78
True or false: Aldehydes can be isolated from the reduction of carboxylic acids.
FALSE
## Footnote
Aldehydes are immediately reduced further to primary alcohols.
79
Provide an example of the reduction of **ethanoic acid**.
Ethanoic acid + 4[H] → Ethanol + H2O
## Footnote
This illustrates the reduction process from a carboxylic acid to a primary alcohol.
80
**Carboxylic acids** are classified as what type of acids?
Weak acids
## Footnote
They react with bases in a neutralisation reaction.
81
What do carboxylic acids produce when they react with bases in a **neutralisation reaction**?
A salt
## Footnote
This is a characteristic reaction of weak acids with bases.
82
In the reaction **CH₃COOH + NaOH →** what is the product formed?
CH₃COONa + H₂O
## Footnote
This reaction illustrates the neutralisation of acetic acid with sodium hydroxide.
83
What is the product of the reaction **CH₃CH₂COOH + NH₃ →**?
CH₃CH₂COONH₄
## Footnote
This product is known as ammonium propanoate.
84
What is the **functional group** of acyl chlorides?
-COCl
## Footnote
Acyl chlorides are derivatives of carboxylic acids where the -OH group is replaced by a chlorine atom.
85
Acyl chlorides react violently due to the presence of the very **polar** ______ group.
-COCl
## Footnote
This polarity contributes to the reactivity of acyl chlorides.
86
Acyl chlorides can be produced by the reaction between **carboxylic acids** and ______.
phosphorus(V) chloride
## Footnote
The chemical formula for phosphorus pentachloride is PCl5.
87
Provide the reaction equation for the formation of acyl chlorides from carboxylic acids and phosphorus(V) chloride.
RCOOH + PCl5 → RCOCl + POCl3 + HCl
## Footnote
This reaction illustrates the conversion of a carboxylic acid to an acyl chloride.
88
What is the process called when **carboxylic acids** react with **alcohols** in the presence of a strong acid catalyst?
Esterification
## Footnote
This reaction typically uses concentrated sulfuric acid as the catalyst and is carried out under reflux.
89
What is often used as the **acid catalyst** in the esterification process?
Concentrated sulfuric acid
## Footnote
It facilitates the reaction between carboxylic acids and alcohols.
90
In the esterification reaction, what is removed from the acid and alcohol to form water?
* -OH from the acid
* Hydrogen from the alcohol
## Footnote
This step is crucial for joining the acid and alcohol together to form an ester.
91
Esters are known for their **sweet-smelling** properties and are commonly used in what applications?
* Food flavourings
* Perfumes
## Footnote
Their pleasant aroma makes them popular in various consumer products.
92
True or false: Esters have **high boiling points** and are poor solvents for polar molecules.
FALSE
## Footnote
Esters have low boiling points and are effective solvents for polar molecules.
93
What is the product formed when **methanol** reacts with **ethanoic acid**?
Methyl ethanoate
## Footnote
This is an example of an ester formed through the esterification process.
94
What is the functional group of **acyl chlorides**?
-COCI
## Footnote
Acyl chlorides have the suffix -oyl chloride, with the stem of their name representing the longest chain of carbon atoms.
95
What suffix is used for **acyl chlorides**?
-oyl chloride
## Footnote
The name represents the longest chain of carbon atoms.
96
What is the functional group of **esters**?
-COO-
## Footnote
Esters are named after the alcohol and carboxylic acid from which they are formed.
97
The ester formed from **methanol** and **propanoic acid** is called _______.
methyl propanoate
## Footnote
This naming convention reflects the components used to form the ester.
98
The ester formed from **butanol** and **ethanoic acid** is called _______.
butyl ethanoate
## Footnote
This naming convention reflects the components used to form the ester.
99
What is another name for **methyl ethanoate**?
methyl acetate
## Footnote
Methyl ethanoate is commonly referred to as methyl acetate.
100
What is the process called when **carboxylic acids** react with **alcohols** in the presence of a strong acid catalyst?
Esterification
| (conc H2SO4)
## Footnote
This reaction typically uses concentrated sulfuric acid as the catalyst and is carried out under reflux.
101
What is often used as the **acid catalyst** in the esterification process?
Concentrated sulfuric acid
## Footnote
It facilitates the reaction between carboxylic acids and alcohols.
102
In the esterification reaction, what is removed from the acid and alcohol to form water?
* -OH from the acid
* Hydrogen from the alcohol
## Footnote
This step is crucial for joining the acid and alcohol together to form an ester.
103
Esters are known for their **sweet-smelling** properties and are commonly used in what applications?
* Food flavourings
* Perfumes
## Footnote
Their pleasant aroma makes them popular in various consumer products.
104
True or false: Esters have **high boiling points** and are poor solvents for polar molecules.
FALSE
## Footnote
Esters have low boiling points and are effective solvents for polar molecules.
105
What is the product formed when **methanol** reacts with **ethanoic acid**?
Methyl ethanoate
## Footnote
This is an example of an ester formed through the esterification process.
106
What group makes **acyl chlorides** very reactive?
-COCI
## Footnote
This group allows acyl chlorides to react with a wide range of molecules.
107
Acyl chlorides react with **water** to produce what?
Carboxylic Acid
## Footnote
This reaction is one of the key transformations involving acyl chlorides.
108
Acyl chlorides react with **alcohol** to form what product?
Ester
## Footnote
The reaction between acyl chlorides and alcohol is a common method for ester synthesis.
109
What product is formed when acyl chlorides react with **ammonia**?
Amide
## Footnote
This reaction illustrates the versatility of acyl chlorides in forming different compounds.
110
Acyl chlorides react with **amines** to yield what type of product?
N-substituted Amide
## Footnote
This reaction showcases the ability of acyl chlorides to form more complex amides.
111
Acyl chlorides undergo reactions via **nucleophilic addition-elimination**. What does the addition of a nucleophile lead to?
Elimination of a product
## Footnote
This process occurs under aqueous conditions and is characteristic of acyl chloride reactions.
112
What is **ester hydrolysis**?
The reverse reaction to esterification, converting esters back into alcohols and carboxylic acids
## Footnote
This process is done by adding water and can be carried out under different conditions to produce different products.
113
What conditions produce a simple reverse reaction back to the alcohol and carboxylic acid during **ester hydrolysis**?
Acidic Conditions
## Footnote
The reaction involves adding water and an acid catalyst.
114
In **alkaline conditions**, what are the products of ester hydrolysis?
* Carboxylate salt
* Alcohol
## Footnote
The carboxylic acid produced reacts further with the base to form a salt.
115
What is the process of producing a carboxylate salt from an ester and a base called?
Saponification
## Footnote
Salts produced in this process are commonly used as soaps due to their hydrophilic and hydrophobic properties.
116
True or false: **Saponification** is the process of converting esters into alcohols and carboxylic acids.
FALSE
## Footnote
Saponification refers specifically to the formation of carboxylate salts from esters and bases.
117
What is **ester hydrolysis**?
The reverse reaction to esterification, converting esters back into alcohols and carboxylic acids
## Footnote
This process is done by adding water and can be carried out under different conditions to produce different products.
118
What conditions produce a simple reverse reaction back to the alcohol and carboxylic acid during **ester hydrolysis**?
Acidic Conditions
| (dilute H2SO4 or HCl)
## Footnote
The reaction involves adding water and an acid catalyst.
119
In **alkaline conditions**, what are the products of ester hydrolysis?
* Carboxylate salt
* Alcohol
## Footnote
The carboxylic acid produced reacts further with the base to form a salt.
120
What is the process of producing a carboxylate salt from an ester and a base called?
Saponification
## Footnote
Salts produced in this process are commonly used as soaps due to their hydrophilic and hydrophobic properties.
121
True or false: **Saponification** is the process of converting esters into alcohols and carboxylic acids.
FALSE
## Footnote
Saponification refers specifically to the formation of carboxylate salts from esters and bases.
122
What are **condensation polymers**?
Polymers formed when a water molecule is removed from the species of a reaction
## Footnote
This process typically involves the reaction of monomers.
123
What type of polymer is formed from a reaction between a **dicarboxylic acid** and a **diol**?
Polyesters
## Footnote
This reaction produces an ester linkage, -COO-.
124
Fill in the blank: **Polyesters** are formed from a reaction between a dicarboxylic acid and a _______.
diol
## Footnote
The reaction results in the formation of an ester linkage.
125
What linkage is produced in the formation of polyesters?
-COO-
## Footnote
This ester linkage is a key feature of polyester structure.
126
What is **Terylene (PET)** made from?
* ethanediol
* 1,4-benzenedicarboxylic acid
## Footnote
Terylene is a common polyester.
127
Why are **polyesters** considered useful?
They can be broken down through hydrolysis due to the polarity within the polymer molecules
## Footnote
This property makes them biodegradable and allows them to break down easily in nature.
128
True or false: **Polyesters** can be put into landfill where they will gradually break down.
TRUE
## Footnote
Polyesters can be broken down by naturally occurring water or moisture.
A Level Chem
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