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uworld orgo Flashcards

1
Q

the compound 4-nitrophenol contains all of the following in its infrared spectrum except

A

N-H stretch

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2
Q

IR spectrum of a compound indicates

A

the types of bonds and functional groups present in a compound

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3
Q

different functional groups absorb

A

IR radiation at diff frequencies

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4
Q

signal from each group appears in a

A

particular region of the IR spectrum

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5
Q

individual molecules may have distinct absorption spectra in the fingerprint region (700-1500 cm-1)…

A

each func group on the molecule will still absorb in its characteristic IR region

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6
Q

4-nitrophenol contains

A

hydroxyl group (-OH)

aromatic ring

nitro groups (-NO2)

no N-H bonds –> no N-H stretch

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7
Q

functional group bands appear in the

A

same region of the IR spectrum regardless of molecule’s overall structure

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8
Q

distillation is a

A

purification technique that separates molecules based on boiling point

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9
Q

a liquid mixture is heated to a temp that overcomes the

A

intermolecular forces keeping the compound in the liquid phase

vapors condense in the collection flask as a liquid

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10
Q

molecule that dissipates in strong IM forces will have a higher or lower boiling pt?

A

a higher boiling point

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11
Q

hydrogen bonding can be

A

intermolecular

intramolecular

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12
Q

constitutional isomers can have different

A

boiling points due to difference in connectivity and that they experience different IM forces

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13
Q

parasubstituent

A

1,4 relationship

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14
Q

ortho substituent

A

1,2 relationship

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15
Q

hydroxyl and nitro groups on 4-nitrophenol are…

A

para

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16
Q

because of para hydroxyl and nitro groups on 4-nitrophenol, they are able to

A

H bond intermoleculary not intramolecularly

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17
Q

intermolecular bonds hold molecules of 4-nitrophenol together, thereby..

A

increasing the boiling pt and causing i.t. to stay in the flask while the 2-nitrophenol distills

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18
Q

superheating occurs when

A

a liquid is heated above its boiling pt but does NOT boil

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19
Q

what can cause superheating?

A

surface tension - it inhibits formation of bubbles

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20
Q

when bubbles attempt to form during superheating…

A

surface tension causes a local increase in vapor pressure

vapor pressure > ambient pressure

liquid heats beyond boiling pt

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21
Q

bumping is

A

the formation of large bubbles at the surface that erupt and eject the hot liquid from the flask

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22
Q

consequence of bumping

A

difficult to overcomes without damage to the flask

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23
Q

boiling chips are made of

A

nonreactive porous materials + provides nucleation sites

24
Q

nucleation sites

A

divots on surface of boiling chip

25
Q

boiling chips facilitate the

A

even boiling of water in the flask

prevents superheating

26
Q

what technique could monitor the formation of 4-aminophenol by excitation of electrons w/ high energy photons?

A

TLC

27
Q

thin layer chromatography (tlc)

A

monitors reactions

28
Q

what can be used to visualized results from TLC?

A

UV light but only if the reaction mixture can absorb the UV light

29
Q

UV light carries a large amount of

A

energy that excites electrons of UV chromophores to a higher E state

30
Q

UV chromophores includes

A

double and triple bonds

carbonyls (C=O)

nitroso groups

alkyl halides

conjugated systems

31
Q

aromatic ring in the starting material of the rxn (4-nitrophenol) and the product (4-aminophenol) is a

A

UV chromophore

each compound can absorb UV light and appears on TLC place

32
Q

in mass spectrometry, a sample is

A

ionized by high energy electrons

electrons do not change E levels

33
Q

an external magnetic field is applied to a sample in

A

NMR spectroscopy

34
Q

radio waves are used to

A

detect H atoms and excite them from the alpha-spin to the beta spin state

radio waves are low in E

35
Q

gas chromatography requires

A

vaporization of a sample (phase change)

not an electronic excitation

36
Q

Rf =

A

distance compound traveled from origin / distance from origin to solvent front

37
Q

TLC is a technique used to

A

separate compounds based on polarity

38
Q

mobile phase

A

organic solvent travels up the stationary phase via capillary action

39
Q

stationary phase

A

a thing absorbent place coated w/ silica

40
Q

low capillary action

A

low adhesive forces on top > high adhesive forces

41
Q

more capillary action

A

low cohesive forces on bottom > high adhesive forces on top

42
Q

components of a mixture travel up the plate at

A

different rates b/c of varying polarity

43
Q

in normal TLC, nonpolar compounds travel

A

further up the plate

have less affinity for the polar stationary phase

44
Q

Rf value is always

A

less than 1

45
Q

smaller Rf =

A

more polar, less mobile compounds

46
Q

amide has more

A

H bond accepts

47
Q

amine is a

A

H bond donor and acceptor via only one electronegative atom (N)

48
Q

amide is a

A

H bond donor and acceptor via two electroneg atoms (O and N)

49
Q

O-H stretch (phenol)

A

3650-3200 cm-1

50
Q

C-C stretch

A

1600-1475 cm-1

51
Q

sp2 C-H stretch

A

3100 cm-1

52
Q

NH stretch (amide)

A

3550-3060 cm-1

53
Q

C=O stretch (amide)

A

1650 cm-1

54
Q

sp3 C-H stretch

A

3000 cm-1

55
Q

acetaminophen contains several functional groups including

A

phenol (hydroxyl group)

aromatic ring

amide (strong absorption in IR spectrum)

56
Q

carbonyl (C=O) group from an amide shows an absorption from

A

1690-1650 cm-1

orgo (6 decks)

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