Mechanisms

Question 1

First stage in the formation of haloalkanes

Answer 1

Initiation

Question 2

Second stage of the formation of haloalkanes

Answer 2

Propagation part 1 and 2

Question 3

Final stage of formation of alkanes

Answer 3

Termination

Question 4

What is required for initiation

Answer 4

Ultraviolet light

Question 5

What is created during initiation

Answer 5

A halogen radical

Question 6

What affects the composition of a radical

Answer 6

The electronegativity

Question 7

Free radicals are

Answer 7

Highly reactive

Question 8

What happens in initiation

Answer 8

A uv photon creates a free radical pair from a diatomic molecule

Question 9

What happens in step one of propagation

Answer 9

The radical steals a hydrogen from the alkane creating a H-halogen molecule and an alkane with a radicalised carbon

Question 10

What happens in step 2 of propagation

Answer 10

The radicalised carbon in the alkane strips a halogen of a diatomic molecule and forms a haloalkanes and a radicalised halogen

Question 11

What is termination

Answer 11

When 2 radicals bond together to form a molecule with no radicals present

Question 12

An example of a product created during termination

Answer 12

Cl2

Question 13

An example of a free radical substitution

Answer 13

The destruction of Ozone

Question 14

How are haloalkanes formed

Answer 14

Free radical substitution

Question 15

Why are CFC’s so destructive

Answer 15

The chlorine radical

Question 16

Nucleophilic substitution

Answer 16

When a Nucleophile substitutes itself with a halogen forming a halogen -1 ion

Question 17

What do curly arrows represent

Answer 17

A movement of electrons

Question 18

What do one headed curly arrows mean

Answer 18

Only one electron Moving

Question 19

What does a full headed curly arrow mean

Answer 19

Movement of 2 electrons

Question 20

What is a strong Nucleophile

Answer 20

Hydroxide ion

Question 21

Conditions needed for nucleophilic substitution

Answer 21

A bond with an imbalance in charge (electronegativity)
A negatively charged ion or a molecule with lone pairs

Question 22

How does nucleophilic substitution work step 1

Answer 22

A negatively charged ion or molecule with lone pairs is attracted to the mildly positively charged carbon

Question 23

How does nucleophilic substitution work step 2

Answer 23

The mildly positively charged carbon donates 2 electrons to the halogen bond which displaces it

Question 24

An example of a Nucleophilic substitution reaction

Answer 24

Halogenoalkanes with ammonia

Question 25

First step in halogenoalkanes with ammonia

Answer 25

The lone pairs on the ammonia forms the bond to the mildly positively charged carbon

Question 26

Step two of the reaction of halogenoalkanes with ammonia

Answer 26

The carbon donates electrons to the halogen which is ejected The extra hydrogen is lost to balance charge and the hydrogen forms a dative bond with an excess ammonia

Question 27

What is important for nucleophilic substitution

Answer 27

Lone pairs

Question 28

What is a Nucleophile

Answer 28

It donates an electron pair to from a new covalent bond

Question 29

What is homolytic fission

Answer 29

The splitting of covalent bonds into radicals where the radicals both take an electron

Question 30

What is Heterolytic fission

Answer 30

Where a covalent bond is split and one of the 2 radicals takes both electrons and the other lacks one

Question 31

What is a Electrophile

Answer 31

e- pair/lone pair acceptor

Question 32

What is elimination

Answer 32

Where a molecule with lone pairs steals a hydrogen from a halogenoalkane forming an alkene

Question 33

What are the conditions for elimination

Answer 33

A molecule with lone pairs and a haloalkane with a hydrogen diagonal from a halogen

Question 34

Mechanism of bromoethene and sodium hydroxide step 1

Answer 34

The OH with lone pairs steal a hydrogen from a carbon

Question 35

Mechanism of bromoethene and sodium hydroxide step 2

Answer 35

The electrons from tech stolen hydrogen pass to the carbon carbon bond turning it into a carbon double bond

Question 36

Mechanism for bromoethene and sodium hydroxide step 3

Answer 36

The double bond displace the bromine turning it into a Br- minus ion

Question 37

What conditions favour substitution

Answer 37

Cold OH- in water

Question 38

What conditions favour elimination

Answer 38

Hot OH- in ethanol

Question 39

Definition of addition

Answer 39

Reaction which increases number of substituents or convert double bonds to single bonds or where 2 molecules from one molecule

Question 40

What is Electrophilic addition

Answer 40

Where a alkene becomes an alkane with extra stuff added

Question 41

What are the conditions for Electrophilic addition

Answer 41

Needs a carbon carbon double bond and an Electrophile

Question 42

Rough mechanism for Electrophilic addition

Answer 42

1.the Electrophile is attracted to the double bond 2.Electrophiles are positively charged and accept a pair of electrons from a double bond. The Electrophile may be positively charged 3.a positive ion is formed (a carbocation) 4. A negatively charged ion forms a Bond with the carbocation

Question 43

Example of Electrophilic addition

Answer 43

The reaction of propane and sulfuric acid

Question 44

What happens when ethene reacts with sulfuric acid step 1

Answer 44

The hydrogen is stolen by the double bond

Question 45

What happens when ethene reacts with sulfuric acid step 2

Answer 45

The double bond opens up and bonds to the lone pair on the hydrogensulfate

Question 46

What happens when you add water to the products of ethene and concentrated sulfuric acid

Answer 46

Ethanol is formed

Question 47

How is ethanol formed from ethyl hydrogensulfate

Answer 47

The hydrogen from the water is stolen by the hydrogensulfate and the OH- bonds with the spare electrons and ethanol is formed

Question 48

What is dehydration

Answer 48

When a water is produced and a functional groups of alcohol is removed

Question 49

How does dehydration work

Answer 49

Either an aluminium oxide catalyst breaks bonds and forms water or a H+ ion causes an elimination reaction and a alkene is formed

Question 50

What are the conditions for dehydration via aluminium oxide catalyst

Answer 50

600K Al2O3 catalyst

Question 51

What are the conditions for dehydration via elimination

Answer 51

Hot excess sulfuric acid

Question 52

What is fermentation

Answer 52

When glucose is fermented into ethanol using organic processes

Question 53

Conditions for the fermentation of ethanol from glucose

Answer 53

Yeast catalyst Anaerobic conditions 310K