Chapter 21 Flashcards

1
Q

describe what the benzene structure is like

A

it is a hybrid of 2 different resonance structures

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2
Q

is the benzene structure of 2 structures in equilibrium ?

A

no , the bonds are not moving back and forth

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3
Q

does benzene undergo additon reactions

A

no

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4
Q

does benzene undergo oxidation reactions

A

no

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5
Q

does benzene underdo reduction reactions

A

no

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6
Q

what kind of reactions does benzene undergo

A

electrophili aromatic substituion

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7
Q

are the bonds in a benzene structure single or double

A

neither , they are somewhere inbetween

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8
Q

how many carbons are in benzene

A

6

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9
Q

what does the carbon skeleton look like on benzene

A

it is a planar regular hexagon

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10
Q

what are the angles of the c-c-c bonds on benzene

A

120

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11
Q

what are the angles of the H-c-c bonds on benzene

A

120

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12
Q

what is the hybridization of the carbons on benzene

A

sp2

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13
Q

what kind of orbrtals do the carbons have in benzene

A

unhybridized 2p orbitals

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14
Q

there are 6 ? in benzene

A

2p

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15
Q

what overlaps on benzene

A

the 2p orbitals over lapp

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16
Q

what is resonance energy

A

the difference in energy between a resonance hybrid and the most stable of its hypothetical contributing structures in which electrons are localised on a particular atims and in particular bonds

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17
Q

how can you estimate the resonance energy of benzene

A

compare the heats of hydrogenation

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18
Q

how do we know that benzene is more stable than cyclohexatriene

A

because it is lower in energy

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19
Q

what are the 4 things that make something aromatic

A

cyclic, 1 2p orbital on each ring, be planar, 4n+2

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20
Q

how many pi electrons 14 annulene

A

14

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21
Q

how do you count the pi electrons on moleucles

A

count each dou7ble bond as 2 pi electons

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22
Q

is 14 annulene aromatic

A

yes

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23
Q

is 18 annulene aromatic

A

yes

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24
Q

is 10 annulene

A

it should be , but it is not !!!

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25
Q

why isnt annulene planar ?

A

because it is non planar confirmaiton, the hydrogens are too close so they bump into each other

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26
Q

how can you make 10annulene planar

A

is you repalce the 2 hydrogens with ch2 you can make it planar

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27
Q

what is an antiaromatic hydrocarbon

A

a monocyclic planar , planar with 4N PI ELECTRONS

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28
Q

What are the numbers for antiaomatic

A

4,8,12,16,20

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29
Q

are antiaromatic compounds stable

A

no

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30
Q

what makes cyclooctatriene special ?

A

it has 8 pi electrons should it should be antiaromatic , buttttt it looks like a tub so it is non planar which makes it non aromatic

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31
Q

what is a heterocyclic compound

A

a compound that contains more than 1 kind of atom in a ring , in o chem the term refers to a ring with one or more atoms that differ from the carbon

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32
Q

give 2 examples of heterocyclic compounds

A

pyradine and pyramidine

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33
Q

what is the hybridization of of the nitrogen atom in pyradine

A

it is sp2 hybridized

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34
Q

where do the unshared pairs of electrons lie in pyradine

A

the unshared pair of electrons lie in an sp2 hybrid orbital and it is not apart of the aromatic sextet

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35
Q

are the unshared pairs of electrons part of the aromatic sextet on pyradine ?

A

no

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36
Q

what is the resonance energy of pyraide

A

134 kj

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37
Q

what is the hybridization on the oxygen in furan

A

sp2

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38
Q

where are the unshared pairs of electrons in furan

A

one unshared pair is on oxygen in an unhybridized 2p orbital and the other is in an sp2 hybrid orbital and the not apart of the aromatic system

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39
Q

what is the name of the orbital that unshared pairs of electrons lie in furan that are NOT Apart of the sextet

A

in sp2 hybrid orbital

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40
Q

what is the name of the orbital that the unshared pair of electrons are in that IS APART of the aromatic sextet . on furan

A

2p hybrid orbital

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41
Q

what is the resoncan ebnergy of furan

A

67

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42
Q

if a hydrocaron has an odd number of carbon s what does that mean

A

it means that it must have 1 ch2 group which means that it is not aromatic

43
Q

to convert cyclopentadiene to an aromatic ion what would you do

A

convert ch2 to a ch group in which carbon becomes sp2 hybridized and has 2 electrons in its unhybridized 2p orbtial

44
Q

what does phenol look like

A

benzene with oh

45
Q

what does aniline look like

A

benzene with Nh2 on top

46
Q

what does benzaldehyde look like

A

benzene with cho on top

47
Q

what does benzoic acid look like

A

benzene with cooh on top

48
Q

what does anisol look like

A

benzene with och3 on top

49
Q

what does tolulene look like

A

benzene with methyl

50
Q

what does styrene look like

A

benzene with ethyl with double bond

51
Q

what does cumene look like

A

benzene with an isopropyl attached to it

52
Q

what is phenyl

A

it is a group that is a long chain on benzene

53
Q

what is ortho, meta and para

A

they help to locate groups on benzenes.
ortho= 1,2
meta=1,3
para=1,4

54
Q

do all of the bonds on carbon have the same lenght and energy

A

yes

55
Q

if there is a disubstituted benzene and non onf the gorups have special names how do you name them

A

locate the groups and put them in alphabetical order .

56
Q

what is the functional group of phenol

A

it is an oh group bonded to a benzene ring

57
Q

are phenol more or less acidic than alcohols

A

they are much more acidic than alcohols

58
Q

why are phenols more acidic than alcohols

A

because you can write more resonance structures , and the stability of the conjugate base

59
Q

are alkyl groups electron releasing or electron withdrawing

A

electron releasing

60
Q

are halogens electron withdrawing or electron releasing

A

electron withdrawing

61
Q

what do alkyl and halogen substituants do to phenols

A

they affect the acidity by inductive effect

62
Q

when comparing a phenol and chlorphenol which is more acidic

A

cholorphenol

63
Q

what do nitro groups do to phenols

A

they increase the acidity of phenols

64
Q

what are the 2 reasons why nitro groups increase the acidity of phenols

A

electron withdrawing inductive effect and resonance effect

65
Q

which 2 positions delocalize the negative charge when adding NO2 to phenols

A

ortho and para

66
Q

are phenols strong or weak acids

A

phenols are weak acids

67
Q

do phenols react with strong or weak bases

A

strong bases

68
Q

when a phenol reacts with a strong base like naoh what is formed

A

water soluable salts and water

69
Q

can you dissolve phenoxide in h20?

A

yes

70
Q

can you seperate are phenol from alcohol ?

A

yes

71
Q

do phenols react with weak bases ?

A

no

72
Q

if you react a haloalkane (benzene with halogen ) + a phenoxide salt (rona +what do you get

A

no reaction

73
Q

can the halogen be attached to the benzene when doing williamson ether ?

A

no

74
Q

what does kolbe carboxilation look like

A

a phenoxide ion ( benzene plus an oh h group that is miussing an h ) + co2

75
Q

what is the end product of kolbe carboxilation

A

a carboxylic salt . this looks like phenol (benzene with oh ) with cooh added to it

76
Q

can phenols get oxidized

A

yes

77
Q

what are the 2 reagents that you can use to reduce phenols ?

A

H2CRO4 & K2Cro7

78
Q

what does a reduced phenol look like ?

A

oh–> o and take away a double bond

79
Q

can phenols get reduced

A

yes

80
Q

what is the reagent that you can use to reduce a phenol

A

na2s204,h2o

81
Q

what does a reduced phenol look like ?

A

change o to oh and add a bond to benzene

82
Q

if there are halogens and nitro groups attatched to phenol and you use h2cro04 what will occur

A

nothing, they are unaffected

83
Q

if there are ch3 groups on benzene what will happen if you use h2cro4

A

the ch3 will turn in cooh

84
Q

if there is more than 1 ch3 group on benzene what will happen and it is oxidized with h2cro4 ?

A

both of the ch3 groups will turn into cooh

85
Q

if you have a benzene with a substituant like toluelee and add cl2 what happens

A

one h falls off of the ch3 and 1 cl adds + hcl

86
Q

ethyl benzene (benzene + ethyl chain) + NBS =

A

A Br adds onto the benzyl carbon (like the beta carbon )

87
Q

what is hydrogenolysis ?

A

cleavage of a single bond by h2

88
Q

what reagents are used for hydrogenalysis

A

H2, PD/C

89
Q

Describe in words what happens in hydrogenalysisis

A

cleave at the beta carbon and there MUST BE AN O NEXT TO THE BENZYL CARBON . add an h to the chain and me to the benzene

90
Q

what is the value of a benzyl either

A

they are protecting groups for the oh groups of alcholos and phenols

91
Q

Are double bonds moving in phenols ?

A

no , the double bonds are not moving

92
Q

what is the hybridization of carbons in benzene ?

A

it is sp2

93
Q

what kind of orbitals do carbons have in benzene

A

they all have unhybrizied p orbiatls

94
Q

how many electrons in each p orbital on benzene ?

A

1 electron

95
Q

how many electron clouds are there in benzene

A

2

96
Q

how many p orbital are in benzene

A

6 , 3 bond and 3 antibonding

97
Q

are the orbitals degenerate in benzene?

A

yes they are all of the same energy

98
Q

which is more stable an open chain or a ring

A

a ring

99
Q

what are the aromatic numbers

A

2,6,10,14,18

100
Q

is pyradine aromatic

A

yes it has 6 electrons because we do not count the lone pair that is on nitrogen

101
Q

in what orbital is the lone pair in pyradine

A

in the sp2 orbital (not part of sextet)

102
Q

how many electrons are on pyrrol

A

6 pi

103
Q

in funan how many pi electrons are there

A

there are 6 . even though it looks like 8 , one of the pairs is not apartt of the sextet.