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1
Q

what is the net charge of a basic amino acid @ physiological pH?

A

+

2
Q

What type of bond joins amino acids?

A

peptide

3
Q

Define amphoteric

A

basic/acidic

4
Q

what type of spectroscopy is useful for identifying functional groups?

A

IR

5
Q

Do symmetrical stretches exhibit an IR absorption signal?

A

No

6
Q

(T/F) NMR spectroscopy can be used to identify distinct H protons in a molecule

A

True

7
Q

what separation technique makes use of two immiscible solvents?

A

extraction

8
Q

What separation technique can be used to isolate a solid from a liquid?

A

diltration

9
Q

(T/F) Re-crystallization is a process in which impure crystals are dissolved in hot solvent and then recrystallize as pure crystals as the solvent cools.

A

True

10
Q

(T/F) An imine is a compound with a carbon-nitrogen double bond.

A

True

11
Q

Which types of amines can form hydrogen bonds (1,2,3)

A

1 & 2 amines can form hydrogen bonds.

12
Q

(T/F) Anhydrides react under the same conditions as acid chlorides.

A

True

13
Q

(T/F) Acid chlorides are very reactives.

A

True

14
Q

How do electron donating groups affect the acidity of benzoic acid?

A

reduce the acidity

15
Q

How do electron withdrawling groups affect the acidity of benzoic acid?

A

increase the acidity

16
Q

what is a micelle?

is the interior hydrophobic or hydrophilic?

A

soap molecules. polar head non-polar inside.

17
Q

would you have to oxidize or reduce a carboxylic acid to prepare an alcohol?

A

reduce

18
Q

what happens when aldehydes or ketones react with water?

A

form gemdiols

19
Q

(T/F) Activating compounds are always o-p directors.

A

True

20
Q

(T/F) Deactivating compounds are always meta directors.

A

False,

halogens are o-p directing

21
Q

Do electron donating groups activate or deactivate an aromatic group?

A

EDG activate a group

22
Q

How do electron withdrawing groups affect the reactivity of an aromatic ring?

A

EWG deactivate a group

23
Q

what is an aromatic compound?

A

unusually stable ring system.

aromatic compounds are cyclic, conjugates polyenes that follow huckels rule

24
Q

what is an aliphatic compound?

A

non-aromatic compund

25
Q

what is huckels rule?

A

(4n+2)π

26
Q

what is an antiaromatic compound?

A

cyclic conjugated polyene with 4n electrons

27
Q

Does the electrophilic addition of HBr to an alkyne follow markovnikov’s rule?

A

yes

28
Q

Does free radical addition of HBr to an alkyne follow markovnikov’s rule?

A

No

29
Q

(T/F) E1 and SN1 reactions are driven by the same factors (polar solvent, good leaving groups, highly branched chains, etc)

A

True

30
Q

Which type of elimination reaction uses a carboncation intermediate?

A

E1 reactions use a carboncation intermediate.

31
Q

(T/F) In the case of E2, the least substituted double bond is usually formed preferentially.

A

False.

E2 reaction favor the information of highly substituted double bond.

32
Q

which type of reaction is favored (SN1 or SN2) given the following conditions?
Polar protic solvent

A

SN1

33
Q

which type of reaction is favored (SN1 or SN2) given the following conditions?
Polar aprotic solvent

A

SN2

34
Q

which type of reaction is favored (SN1 or SN2) given the following conditions?
Methyl or 1 alkyl halide

A

SN2

35
Q

which type of reaction is favored (SN1 or SN2) given the following conditions?
3 Alkyl halide

A

SN1

36
Q

what are the three steps of a halogenation reaction?

A

Initiation, propagation and termination

37
Q

(T/F) All single bonds are sigma bonds.

A

True

38
Q

what type of bonds results when two p orbitals overlap?

A

Pi bonds

39
Q

What are the components of a double bond?

A

1 sigma and pi bond.

40
Q

What are the components of a triple bond?

A

1 sigma and 2 pi bonds.

41
Q

what types of molecules are optically active?

A

chiral molecules

42
Q

what is a meso compound?

A

molecule that posseses stereocenters but has a plane of symmetry

43
Q

what is a levoratory (-) compound?

A

rotates polarized light to the left (counterclockwise)

44
Q

what is a racemic mixture?

A

contains equal amounts of both enantiomers

45
Q

how many stereoisomers are possible for a molecule with four chiral centers?

A

2^4=16

46
Q

what are diastereomers?

A

stereoisomers that are not mirror images of each other.

47
Q

order the following conformations of n-butane according to energy levels (low to high): gauche, anti, eclipsed, totallu eclipsed.

A

anti
gauche
eclipsed
totally eclipsed

48
Q

what are the two primary classifications (regarding tertiary structure) of protein?

A

Fibrous and globular proteins

49
Q

Define quaternary structure.

A

only exists in proteins with more than one polypeptide subunit. It refers to the way the subunits arrange themselves.

50
Q

what is a conjugated protein?

A

protein that derives part of its function from a prosthetic group.

51
Q

what happens when a protein denatures?

what can cause a protein to denature?

A

looses its 3D shape. Changes in temp, pH, and solute concentration can make a protein denature.

52
Q

define the primary structure of a protein.

A

primary structure refers to the sequence of amino acids

53
Q

define secondary structure

A

refers to hydrogen bond interactions within the protein.

54
Q

what are the two most common types of secondary structure?

A

alpha-helix and beta-pleated sheet

55
Q

define tertiary structure

A

3D folding of a protein

56
Q

(T/F) The buffering capacity of an amino acid is greatest at its isoelectric point.

A

False.
The buffering capacity of an amino acid is least at its isoelectric point.
It is greatest at its two or more pKa’s.

57
Q

where are non-polar amino acids usually found in a protein and why?

A

Non-polar amino acids are usually found in the interior of a protein becuase they are hydrophobic.

58
Q

where are polar amino acids usually found in a protein?

A

Polar amino acids are usually found on the exterior of a protein

59
Q

what is the net charge of an acidic amino acid at physiological pH?

A

The net charge of an acidic amino acid at physiological pH is negative.

60
Q

In what direction will an amino acid with a neutral side chain move during electrophoresis at pH 4:
If the pI of the amino acid is 7?

A

The amino acid will have a net positive charge and, therefore,move towards the cathode.

61
Q

In what direction will an amino acid with a neutral side chain move during electrophoresis at pH 4:
If the pI of the amino acid is 3?

A

the amino acid will have a net negative charge and , therefore, move towards the anode

62
Q

In what direction will an amino acid with a neutral side chain move during electrophoresis at pH 4:
If the pI of the amino acid is 4?

A

the amino acid is at its isoelectric point and will not move.

63
Q

(T/F) The alpha carbon is chiral in all amino acids.

A

False.

Glycine’s alpha carbon has 2 hydrogen and is therefore not chiral.

64
Q

what is a zwitterion?

A

species with both a positive and negative charge

65
Q

what is a mutarotation?

A

change of configuration about C1 that occurs when monosaccharides are exposed to water.

66
Q

(T/F) Glucose is an aldohexose.

A

True

67
Q

(T/F) Fructose is an aldopentose.

A

False.

Fructose is a ketohexose.

68
Q

What is a reducing sugar?

A

any monosaccharide with a hemiacetal ring

69
Q

(T/F) When converting a fisher projection to a haworth (ring) projection, groups on the ring side of fischer projection will be pointing upward.

A

False.

Groups on the right side of a fischer projection end up pointing downward in Haworth projection.

70
Q

what monosaccharides make up a molecule of maltose?

A

Maltose is composed of two molecules of glucose.

71
Q

does cellulose contain B-1,4 glycosidic bonds or alpha-1,4 glycosidic bonds?

A

Cellulose contains B-1,4 glycosidic bonds.

72
Q

Do starch and glycogen contain Beta-1,4 glycogen contain B-1,4 glycosidic bonds or alpha-1,4 glycosidic bonds?

A

Starch and glycogen contain alpha-1,4 glycosidic bonds.

73
Q

(T/F) Monosaccharides undergo many of the same reaction as alcohols.

A

True

74
Q

What is the general formula for calculating the max number of possible stereoisomers of a molecule?

A

The general formula is 2^n when n= number of chiral center.

75
Q

A pyranose has how many members in its ring?

A

A pyranose has a six-member ring.

76
Q

A furanose has how many members in its ring?

A

A furanose has a five-member ring.

77
Q

What is the general formula for a carbohydrate?

A

Cn(H2O)m

78
Q

What type of spectroscopy is ideal for the study of conjugated olefins?

A

UV-vis

79
Q

What type of spectroscopy can determine the molecular weight of compound?

A

Mass spectroscopy

80
Q

How many different NMR peaks (doublets, triplets, etc) would appear if the molecule being analyzed were:
Ethane

A

1 singlet

81
Q

How many different NMR peaks 9doublets, triplets, etc) would appear if the molecule being analyzed were:
Propane

A

1 septet

1 triplet

82
Q

How many different NMR peaks 9doublets, triplets, etc) would appear if the molecule being analyzed were:
1,3-dicholoropropane

A

1 quintet

1 triplet

83
Q

How many different types of equivalent protons are there is 1-bromo-2-chloropropane?

A

3 diff types

84
Q

SDS-polyacrylamide gel electrophoresis separates proteins based on what factor?

A

masses

85
Q

(T/F) Agarose gel electrophoresis is used to separate fragments of nucleic acid.

A

true

86
Q

what is the Rf value in thin layer chromatography (TLC)?

A

Compound travels divided by the distance the solvent travels

87
Q

Would a compound with a high Rf value be near the top or near the bottom of a TLC plate?

A

top

88
Q

Which separation technique uses an electric field?

A

electrophoresis

89
Q

(T/F) Vacuum distillation can be used to separate liquids with very high boiling points.

A

True

90
Q

which separation technique separates compounds based upon their different affinities for a medium?

A

Chromatography

91
Q

which purification technique involves a solid turning directly into a gas?

A

Sublimation

92
Q

Which separation technique can be used to separate a mixture of particles with different densities and masses?

A

Centrifugation

93
Q

Which separation technique takes advantage of a solution containing two or more compounds with different boiling points?

A

Distillation

94
Q

How many alkyl group are in a tertiary (3) amine?

A

A 3 amine has 3 alkyl groups attached to the nitrogen.

95
Q

What is a quaternary ammonium compound?

A

A quaternary ammonium compound is a nitrogen atom attached to 4 alkyl groups. The nitrogen is positively-charged and, therefore, the compound exist as a salt.

96
Q

What are the products for the hydrolysis of an ester?

A

carboxylic acid & an alcohol

97
Q

(T/F) A glycerol molecule attached to two carboxylic acids and one phosphoric acid is a phospholipid.

A

True

98
Q

What is saponification?

A

fats are hydrolyzed, under basic conditions, to produce soaps.

99
Q

what is the product of hydrolysis of an amide under acidic conditions?

A

The hydrolysis of an amide under acidic conditions will produce a carboxylic acid.

100
Q

Which type of alcohol (1,2,3) can be oxidized to a carboxylic acid?

A

1 alcohols can be oxidized to carboxylic acids, however 2 & 3 alcohols cannot.

101
Q

How do electrons withdrawing groups (-Cl, NO2) attached to the alpha carbon affect the acidity of a carboxylic acid?

A

Electron withdrawing group increase acidity.

102
Q

How do electron donating groups (-NH2, -OCH3) attached to the alpha carbon affect the acidity of a carboxylic acid?

A

Electron donating groups decrease acidity.

103
Q

Would you have to oxidize or reduce an aldehyde to create a carboxylic acid?

A

Oxidation of an aldehyde creates a carboxylic acid.

104
Q

Can a tertiary alcohol be easily oxidized?

A

No, tertiary alcohols cannot be oxidized without cleavage of a carbon-carbon bond.

105
Q

Can ethers hydrogen bond?

A

No, ethers do not hydrogen bond.

106
Q

what are three types of reactions used to synthesize alcohols?

A

Three general types of rxns used to prepare alcohols are : addition, substitution & reduction.

107
Q

Why do alcohols have a significantly higher boiling point than analogous alkanes?

A

hydrogen bond

108
Q

(T/F) Phenols are less acidic aliphatic alcohols.

A

false.

phenols more acidic than aliphatic alcohols.

109
Q

what is the difference between a phenyl and a benzyl group?

A

a benzene ring acting as a substituent is called a phenyl group. A toluene molecule substituted at the methyl position is called a benzyl group.

110
Q

(T/F) The reduction of an alkyne on a metal surface (Pd) results in a cis alkane.

A

False.

It results in alkane

111
Q

(T/F) The reduction of an alkyne in Na and NH3 produces a trans alkene.

A

True

112
Q

Which form of an alkene has a higher melting point (cis or trans?

A

The trans form of an alkene has a higher melting point due to its symmetry

113
Q

Which form of an alkene has a higher boiling point (cis or trans?

A

The cis form of an alkene has a higher boiling point due to its polarity

114
Q

How many steps are there in an E1 elimination reaction?

A

2 steps

115
Q

How many steps are there in an E2 elimination reaction?

A

1 steps

116
Q

How many steps are involved in an SN2 reaction?

A

1 step

117
Q

Is the rate of an SN2 reaction dependent on the concentration of the substrate, of the nucleophile, or both?

A

the SN2 reaction rate is dependent on the concentration of both the substrate and the nuc

118
Q

(T/F) SN1 reactions involving a chiral substrate produce an optically active mixture.

A

false.

a recemic mix results during SN1 rxn with an optically active reactant

119
Q

(T/F) SN2 reactions involving a chiral substrate result in an inverted, optically active product.

A

true

120
Q

Which step in an SN1 reaction is the rate determining step?

A

The first, the formation of the carbocation, is the rate determination step.

121
Q

(T/F) The rate of an SN1 reaction is dependent on the concentration of the nucleophile.

A

False.

The rate is only dependent on the concentration of the original molecule.

122
Q

How can SN1 reaction rate be increased?

A

1- Stabilize the carboncation by increasing substitution and using a highly polar solvent.
2- Use a better leaving group (weak base)

123
Q

How does basicity affect the nature of a leaving group?

A

The weaker the base, the better the leaving group.

124
Q

All else being equal, how does basicity affect the strength of a nucleaophile?

A

The stronger the base, the stronger the nucleophile

125
Q

How many steps are involved in an SN1 reaction? what are they?

A

2 steps:
1st- molecule dissociates into a carboncation and a LG.
2nd- the nucleophile combines with the carboncation.