Synthesis

Question 1

What are the two ways bonds can be broken?

Answer 1

• homolytic fission

* heterolytic fission

Question 2

What are free radicals?

Answer 2

unpaired electrons that are highly reactive

Question 3

Are free radicals suitable for synthesis?

Answer 3

no

Question 4

What does a full curly arrow represent?

Answer 4

the movement of a pair of electrons

Question 5

What are nucleophiles?

Answer 5

nucleus seekers that are negatively charged ions or neutral molecules that are electron-rich

Question 6

What are nucleophiles capable of?

Answer 6

donating an electron pair to form a new bond

Question 7

What are electrophiles?

Answer 7

electron seekers-they are positively charged ions or neutral molecules that are electron deficient

Question 8

What are electrophiles capable of?

Answer 8

accepting an electron pair to form a new bond

Question 9

What is an example of a nucleophile?

Answer 9

ammonia

Question 10

What is an example of an electrophile?

Answer 10

water

Question 11

How can monohaloalkanes be classified?

Answer 11

as primary, secondary or tertiary

Question 12

What does an elimination reaction produce?

Answer 12

alkenes

Question 13

What is the overall reaction rate dependent on?

Answer 13

the rate determining step

Question 14

What order is an SN1 reaction?

Answer 14

1st order overall

Question 15

What order is an SN2 reaction?

Answer 15

2nd order overall

Question 16

What are the general rules for SN1 and SN2 mechanisms?

Answer 16

SN1-tertiary haloalkanes

SN2-primary & secondary haloalkanes

Question 17

How can alcohols be prepared?

Answer 17

• fermentation
• nucleophilic substitution
• acid-catalysed hydration

Question 18

What is the reducing agent for the reduction of aldehydes and ketones?

Answer 18

lithium aluminium hydride

Question 19

What chemicals can be used for the oxidation of an alcohol?

Answer 19

• acidified potassium dichromate
• acidified dichromate
• hot copper (II) oxide

Question 20

What can be said about the stages of making an ether?

Answer 20

both stages are irreversible

Question 21

What is the functional group in ethers?

Answer 21

R-O-R

Question 22

What is an SN2 reaction?

Answer 22

• There is only one step
• no carbocation
• a 5 centred transition state

Question 23

How does an SN1 reaction occur?

Answer 23

An SN1 reaction occurs in a minimum of two steps via a trigonal planar carbocation intermediate

Question 24

When are free radicals formed?

Answer 24

when the bond broken is non-polar

Question 25

What do reactions involving free radicals result in?

Answer 25

very complex mixtures of products

Question 26

What are haloalkanes?

Answer 26

Saturated organic compounds derived from alkanes by substituting one or more hydrogen atoms by halogen atoms

Question 27

What happens in elimination reactions?

Answer 27

In elimination reactions, a strong base is used in a solvent of relatively low polarity

Question 28

Why is an SN1 mechanism used for tertiary haloalkanes?

Answer 28

due to their stability

Question 29

What are the two stages involved in making ethers?

Answer 29

stage 1-substitution | stage 2-condensation

Question 30

Reaction of alkali metals with alcohols

Answer 30

alkali metal+alcohol-> metal alkoxide+hydrogen

Question 31

How can ethers be classified?

Answer 31

symmetrical or asymmetrical

Question 32

What are ethers?

Answer 32

alkanes with the alkoxyl functional group attached

Question 33

What is homolytic fission?

Answer 33

the 2 shared electrons separate equally with one going to each atom

Question 34

What is heterolytic fission?

Answer 34

both of the shared electrons go to one of the two atoms forming ions

Question 35

What are carbocations?

Answer 35

A carbocation is an ion with a positively charged carbon atom

Question 36

What can be said about heterolytic fission?

Answer 36

Tends to produce fewer products, therefore, is better suited for synthesis

Question 37

When does heterolytic fission occur?

Answer 37

when a bond is polar

Question 38

How can substitution occur?

Answer 38

By two mechanisms: •SN1 •SN2

Question 39

What happens in nucleophilic substitution?

Answer 39

* The halogen atom is replaced by a nucleophile * This is a result of the C-X bond * The nucleophile denotes a pair of electrons and forms a covalent bond with the carbon

Question 40

Do ethers display hydrogen bonding between molecules?

Answer 40

no

Question 41

Is hydrogen bonding possible between water and ethers?

Answer 41

yes

Question 42

How can ethers be prepared?

Answer 42

By nucleophilic substitution of a monoalkane using a metal alkoxide

Question 43

How can alkenes be prepared?

Answer 43

* dehydration of alcohols | * elimination of hydrogen halides in the presence of a base

Question 44

What are the different reactions with alkenes?

Answer 44

* hydrogenation * halogenation * hydrohalogenation * hydration

Question 45

What is halogentation?

Answer 45

reaction with a halogen

Question 46

What is hydrohalogention?

Answer 46

reaction with a hydrogen halide

Question 47

What is Markovnikov's rule?

Answer 47

The hydrogen atom adds to the carbon of the double bond with the larger number of hydrogens already attached

Question 48

What do alkenes behave as?

Answer 48

nucleophiles

Question 49

Which amines can't hydrogen bond with each other?

Answer 49

tertiary because they have no N-H bonds

Question 50

Which amines have greater bpts?

Answer 50

primary and secondary amines have higher bpts than tertiary amines

Question 51

What are amines?

Answer 51

weak bases

Question 52

What can be said about benzene?

Answer 52

Benzene is a very stable, saturated structure that does not undergo addition reactions

Question 53

Does benzene undergo addition reactions?

Answer 53

no

Question 54

What makes benzene stable?

Answer 54

its 6 delocalised electrons

Question 55

What is a substituted benzene ring called?

Answer 55

phenyl

Question 56

What reactions does benzene tend to undergo?

Answer 56

electrophilic substitution

Question 57

What catalyst is used in the halogenation of benzene?

Answer 57

AlCl₃

Question 58

What is nucleophilic substitution?

Answer 58

Nucleophiles contain either a negative charge or a lone pair of electrons and attack a centre of positive charge on a molecule Nucleophile attacks a carbon with a positive charge and replaces (substitutes) the atom/ group with a negative charge thus leaving the molecule under attack

Question 59

What is the definition of an SN1 reaction?

Answer 59

nucleophilic substitution with only 1 particle involved in the rate-determining step

Question 60

What is the definition of an SN2 reaction?

Answer 60

nucleophilic substitution where 2 particles are involved in the rate-determining step

Question 61

What is the reagent used in an elimination reaction?

Answer 61

Aluminium oxide or concentrated sulphuric acid/concentrated phosphuric acid

Question 62

Why are halides attached to a benzene ring resistant to attack?

Answer 62

Electrophiles are attracted to the delocalised electrons in the benzene ring

Question 63

Why does but-1-ene have no geometric isomers?

Answer 63

Swapping any of the groups on the C=C always results in the same structure

Question 64

How can NMR spectroscopy be used to distinguish between fructose and glucose?

Answer 64

Fructose and glucose will have different proton environments

Question 65

What are examples of dehydrating agents?

Answer 65

Phosphoric acid/ sulphuric acid / aluminium oxide

Question 66

What is the difference between hydration and hydrolysis?

Answer 66

Hydration is often an electrophilic reaction where there is no change in the products Hydrolysis is when there is a breakdown in the reactants using water