MCAT Ochem Flashcards
(175 cards)
1
Q
What are the prefixes for the first 12 alkanes?
A
Meth Eth Prop But Pent Hex Hept OCt Non Dec Undec Dodec
2
Q
What are the 5 steps used to name alkanes according to IUPAC rules?
A
- Find the longest chain
- Number the chain so that the lowest set of numbers is obtained for the substituents
- Name and alphabetize the substituents
- Assign a number to each substituent
- Complete the name
3
Q
In the case of an “en - ol” which carbon receives the lowest number?
A
The carbon attached to the alcohol group is assigned the lowest number
4
Q
What is a diol?
A
A diol is a molecule with 2 hydroxyl (OH) groups
5
Q
T/F: An aldehyde has a carbonyl group somewhere in the middle of a carbon chain.
A
False, In an aldehyde, the carbonyl group is at the end of the carbon chain
6
Q
T/F: A ketone has a carbonyl group at one end of a carbon chain.
A
False, In a ketone, the carbonyl group is somewhere in the middle of the carbon chain
7
Q
In the case of an “en - one” which carbon receives the lowest number?
A
The carbonyl carbon receives the lowest number
8
Q
What type of compound does a -COOH group denote?
A
The COOH group denotes a carboxylic acid
9
Q
What are the common names for the following:
1) methanoic acid
2) ethanoic acid
3) propanoic acid
A
- formic acid
- acetic acid
- propionic acid
10
Q
Name the prefix and suffix for the following:
- Carboxylic Acid
- Ester
- Acyl Halide
A
- carboxy- / -oic acid
- alkoxycarbonyl- / -oate
- halocarbonyl- / -oyl halide
11
Q
Name the prefix and suffix for the following:
- Amide
- Nitrile
- Aldehyde
A
- amido - / -amide
- cyano - / -nitrile
- oxo- / -al
12
Q
Name the prefix and suffix for the following:
- Ketone
- Alcohol
- Thiol
A
- oxo - / -one
- hydroxy - / -ol
- sulfhydryl- / -thiol
13
Q
Name the prefix and suffix for the following:
- Amine
- Ether
- Sulfide
A
- amino- / -amine
- alkoxy- / -ether
- alkylthio- / -sulfide
14
Q
Name the prefix and suffix for the following:
- Nitro
- Azide
- Diazo
A
- nitro- / ~
- azido - / -azide
- diazo- / ~
15
Q
What is structural isomer?
A
Structural isomers have the same chemical formulas, but different atomic connectivity
16
Q
What is a stereoisomer?
A
Stereoisomers are compounds that differ only in respect to the spatial arrangement of their atoms
17
Q
Order the following conformations of n-butane according to energy levels (low to high): gauche, anti, eclipsed, totally eclipsed
A
Anti, gauche, eclipsed, totally eclipsed
18
Q
Order the above hexanes according to energy levels (low to high)
A
Low to high: chair, twisted boat, boat
19
Q
T/F: Axial hydrogens are parallel to the ring
A
False, axial hydrogens are perpendicular to the ring
20
Q
T/F: Bulky groups prefer the equatorial position over the axial position
A
True
21
Q
What are geometric isomers?
A
Geometric isomers are molecules that differ with respect to the spatial relationship of substituents around a doable bond
22
Q
What is a chiral molecule?
A
A chiral molecule is a molecule that is not superimposable upon its mirror image.
Chiral Can’t superimpose
23
Q
What are enantiomers?
A
Enantiomers are chiral molecules that are non-superimposable mirror images of each other.
CHIRAL
MIRROR IMAGES
CAN’T SUPERIMPOSE
24
Q
T/F: Achiral molecules are optically active
A
False, achiral molecules are optically inactive
25
What is a dextrorotatory (+) compound?
A dextrorotatory compound rotates polarized light to the right (clockwise)
26
What is a levorotatory (-) compound?
A levorotatory compound rotates polarized light to the left (counterclockwise)
27
what is a racemic mixture?
A racemic mixture contains equal amounts of both enantiomers
28
How many stereoisomers are possible for a molecule with four chiral centers?
2^4 = 16
29
What are diastereomers?
Diastereomers are stereoisomers that are not mirror images of each other
30
What types of molecules are optically active?
Chiral molecules are optically active
31
What is a meso compound?
A meso compound is a molecule that possesses stereocenters but has a plane of symmetry. It is achiral and therefore optically inactive.
32
What type of chemical bond involves the sharing of electrons?
Covalent bonds involve the sharing of electrons
33
What type of chemical bond involves the transfer of electrons?
Ionic bonds involve the transfer of electrons
34
Which orbital has a spherical shape?
"s" orbitals are spherically shaped
35
Which orbital has a bi-lobed shape?
"p" orbitals are bi-lobed
36
T/F: All single bonds are sigma (σ) bonds
True
37
What type of bond results when two p orbitals overlap?
Two overlapping p orbitals form a pi (π) bond
38
What are the components of a double bond?
A double bond is composed of 1 sigma and 1 pi bond
39
What are the components of a triple bond?
A triple bond is composed of 1 sigma and 2 pi bonds
40
T/F: A pi bond can exist without a sigma bond
False, a pi bond cannot exist independently of a sigma bond
41
Which type of bond (π or σ) is stronger?
A sigma bond is generally stronger than a pi bond
42
What is the hybridization of the carbon atom in CH4? what are the bond angles?
sp^3, 109.5 degrees
43
What is the bond angle between sp hybridized atoms?
180 degrees
44
What is the bond angle between sp^2 hybridized atoms?
120 degrees
45
How many other carbons are 1°, 2°, 3°, and 4° carbons bonded to?
1, 2, 3, and 4 other carbons respectively
46
How does increasing molecular weight affect the boiling point and melting point of an alkane?
Increased molecular weight results in INCREASED boiling and melting points
47
How does increased branching affect the boiling point of an alkane?
Increased branching LOWERS the boiling point
48
What are the 3 steps of a halogenation reaction?
The three steps are:
initiation
propagation
termination
49
What is the order of free radical stability?
3°>2°>1°> methyl
50
What type of reaction involves breaking down large alkanes into smaller ones?
Pyrolysis or "cracking" uses heat to break down large alkanes into smaller ones
51
What are the products of the complete combustion of an alkane?
the complete combustion of an alkane produces:
CO2
H2O
heat
52
Is a nucleophile electron rich or electron poor?
A nucleophile is electron rich
53
All else being equal, how does basicity affect the strength of a nucleophile?
The stronger the base, the stronger the nucleophile
54
How many steps are involved in an SN1 reaction? What are they?
There are 2 steps in an SN1 reaction. 1st - the molecule dissociates into a carbocation and a leaving group.
2nd - the nucleophile combines with the carbocation
55
What is the order of carbocation stability?
3°>2°>1°>methyl
56
Which step in an SN1 reaction is the rate determining step
The first step, the formation of the carbocation is the rate determining step
57
T/F: The rate of an SN2 reaction is dependent on the concentration of the nucleophile
False, the rate is only dependent on the concentration of the original molecule
58
How can SN1 reaction rate be increased?
1. Stabilize the carbocation by increasing substitution and using a highly polar solvent
2. Use a better leaving group (weak base)
59
How does basicity affect the nature of a leaving group?
The weaker the base, the better the leaving group
60
How many steps are involved in an SN2 reaction?
SN2 reactions have one step. concerted
61
Is the rate of an SN2 reaction dependent on the concentration of the substrate, of the nucleophile or both?
The SN2 reaction rate is dependent on the concentration of both the substrate and the nucleophile
62
T/F: SN1 reactions involving a chiral substrate produce an optically active mixture
False, a racemic mixture results during SN1 reactions with an optically active reactant
63
T/F: SN2 reactions involving a chiral substrate result in an inverted, optically active product
True
64
Which type of reaction is favored (SN1 or SN2) given the following conditions?
Polar protic solvent
SN1
65
Which type of reaction is favored (SN1 or SN2) given the following conditions?
Polar aprotic solvent
SN2
66
Which type of reaction is favored (SN1 or SN2) given the following conditions?
Methyl or 1 alkyl halide
Methyl or 1 alkyl halides favor SN2
67
Which type of reaction is favored (SN1 or SN2) given the following conditions?
3 alkyl halide
3 alkyl halides favor SN1
68
T/F: E1 and SN1 reactions are driven by the same factors (polar solvent, good leaving groups, highly branched chains, etc)
True
69
Which form of an alkene has a higher melting point (cis or trans)?
the trans form of an alkene has a higher melting point due to its symmetry
70
Which form of an alkene has a higher boiling point (cis or trans)?
The cis form of an alkene has a higher boiling point due to its polarity
71
T/F: The reduction of an alkyne on a metal surface (Pd) results in a cis alkene
False, It results in an alkane
72
T/F: The reduction of an alkyne in Na and NH3 produces a trans alkene
True
Pd metal: alkyne -----> alkane
Na and NH3: alkyne -----> trans alkene
73
Does the electrophilic addition of HBr to an alkyne follow Markovnikov's rule?
Yes, electrophilic addition of HBr to an alkyne or an alkene follows Markovnikov's rule
74
Does the free radical addition of HBr to an alkyne follow Markovnikov's rule?
No, free radical addition of HBr to an alkyne or an alkene does not follow Markovnikov's rule (ROOR peroxides)
75
What is an aromatic compound?
An aromatic compound is defined as any unusually stable ring system. Aromatic compounds are cyclic, conjugated polyenes that follow Huckel's rule
76
What is an aliphatic compound?
An aliphatic compound is any non-aromatic compound
77
What is Huckel's rule?
Huckel's rule states that an aromatic compound has (4n+2) π electrons, where n is any nonnegative integer
78
What is an antiaromatic compound?
An antiaromatic compound is a cyclic conjugated polyene with 4n electrons
79
Do electron donating groups activate or deactivate an aromatic ring?
Electron donating groups activate the ring
80
How do electron withdrawing groups affect the reactivity of an aromatic ring?
Electron withdrawing groups deactivate a ring
81
List the activating groups:
```
NR2
CH3
OCOR
NH2
OR
```
all ortho/para directing
82
List the Deactivating groups:
COOH
NO2
COOR
SO3H
all meta directors
83
What is the exception for Deactivating groups?
F, Cl, Br, I are all deactivating but are ORTHO/PARA DIRECTING!
84
T/F: Activating compounds are always o/p directors
True
85
T/F: Deactivating compounds are always meta directors
False, halogens (Cl, I, Br, F) are deactivating and o-p directing
86
Why do alcohols have a significantly higher boiling point than analogous alkanes?
Alcohols can hydrogen bond
87
T/F: Phenols are less acidic than aliphatic alcohols
False, phenols are much more acidic than aliphatic alcohols.
88
What are the 3 types of reactions used to synthesize alcohols?
Addition
Substitution
Reduction
89
Can a tertiary alcohol be easily oxidized?
No, tertiary alcohols cannot be oxidized without cleavage of a carbon-carbon bond
90
Can ethers hydrogen bond?
No, ethers do not hydrogen bond
91
How does the boiling point of an aldehyde (or ketone) compare with its analogous alkane? Alcohol?
The boiling point of an aldehyde is HIGHER than that of the corresponding alkane but LOWER than that of the corresponding alcohol
92
How is a ketone or an aldehyde produced from an alcohol?
Oxidizing an alcohol will produce the corresponding ketone or aldehyde (i.e. by using PCC, or Na2Cr2O7)
93
How do you produce a ketone or aldehyde from an alkene?
Ozonolysis of an alkene will produce corresponding ketones or aldehydes as cleavage products
94
Which protons relative to a carbonyl group are acidic?
Alpha protons relative to a carbonyl group are slightly acidic.
95
What happens when aldehydes or ketons react with water?
Aldehyde and ketons react with water to form gem-diols
96
T/F: a reaction in which 2 molecules combine with the loss of a water molecule is a condensation reaction
True
97
What would be the product when acetaldehyde is reacted with dilute NaOH?
What is the name of this type of reaction?
an aldol (be able to draw)
Adol condensation
98
What are the common names for the first three straight chain carboxylic acids?
The first 3 carboxylic acids are:
formic acid
acetic acid
propionic acid
99
T/F: Alcohols have higher boiling points than carboxylic acids
False, carboxylic acids have higher boiling points than corresponding alcohols
100
How do electron withdrawing groups (-Cl, -NO2) attached to the alpha carbon affect the acidity of a carboxylic acid?
Electron withdrawing groups increase acidity
101
How do electron donating groups (-NH2, -OCH3) attached to the alpha carbon affect the acidity of a carboxylic acid
Electron donating groups decrease acidity
102
Would you have to oxidize or reduce an aldehyde to create a carboxylic acid?
Oxidation of an aldehyde creates a carboxylic acid
103
Which type of alcohol (1°,2°, or 3°) can be oxidized to a carboxylic acid?
1° alcohols can be oxidized to carboxylic acids; however, 2° and 3° alcohols cannot
104
What is a micelle? IS the interior hydrophobic or hydrophilic?
When placed in an aqueous solution, soap molecules arrange themselves into spherical structures call micelles.
The soap molecules arrange themselves such that their POLAR heads face outward and their NONPOLAR chains face inward.
105
Would you have to oxidize or reduce a carboxylic acid to prepare an alcohol?
Reduction of a carboxylic acid forms an alcohol
106
T/F: Acid chlorides are very reactive
True
107
How do electron donating grousp affect the acidity of benzoic acid?
Electron donating groups reduce the acidity of benzoic acid
108
How do electron withdrawing groups affect the acidity of benzoic acid?
Electron withdrawing groups increase the acidity of benzoic acid.
109
T/F: Anhydrides react under the same conditions as acid chlorides
True
110
What is the product of the hydrolysis of an amide under acidic conditions
The hydrolysis of an amide under acidic conditions will produce a carboxylic acid
111
What are the products of the hydrolysis of an ester?
The products are a carboxylic acid and an alcohol
112
What is saponification?
Saponification is the process whereby fats are hydrolyzed, under basic conditions, to produce soaps
113
T/F: A glycerol molecule attached to two carboxylic acids and one phosphoric acid is a phospholipid
True
114
How many alkyl groups are in a tertiary amine
A 3° amine has 3 alkyl groups attached to the nitrogen
115
What is a quaternary ammonium compound?
A quaternary ammonium compound is a nitrogen atom attached to 4 alkyl groups. The nitrogen is positively charged and, therefore, the compounds exists as a salt.
116
T/F: An imine is a compound with a carbon-nitrogen double bond
True
117
Which type of amines can form hydrogen bonds?
1° and 2° amines can form hydrogen bonds
118
What separation technique makes use of two immiscible solvents?
Extraction makes use of two immiscible solvents
119
What separation technique can be used to isolate a solid from a liquid?
Filtration can be used to isolate a solid from a liquid
120
T/F: Recrystallization is a process in which impure crystals are dissolved in hot solvent and then recrystallize as pure crystals as the solvent cools.
True
121
Which purification technique involves a solid turning directly into a gas?
Sublimation occurs when a solid turns directly into a gas
122
Which separation technique can be used to separate a mixture of particles with difference densities and masses?
Centrifugation separates based on mass and density
123
Which separation technique takes advantage of a solution containing two or more compounds with different boiling points?
Distillation separates based on different boiling points
124
T/F: Vacuum distillation can be used to separate liquids with very high boiling points
True
125
Which separation technique separates compounds based upon their different affinities for a medium?
Chromatography separates compounds based on their different affinities for a medium
126
What is the Rf value in thin layer chromatography(TLC)?
The Rf value is the distance a compound travels divided by the distance the solvent travels
127
Would a compound with a high Rf value be near the top or near the bottom of a TLC plate?
A compound with a high Rf value would be near the top of a TLC plate
128
Which separation technique uses an electric field?
Electrophoresis uses an electric field
129
T/F: Isoelectric focusing uses a gel with a pH gradient to separate proteins based on their isoelectric points
True
130
SDS-polyacrylamide gel electrophoresis separates proteins based on what factor?
SDS-polyacrylamide gel electrophoresis separates proteins based on their masses
131
T/F: Agarose gel electrophoresis is used to separate fragments of nucleic acid
True
132
What type of spectroscopy is useful for identifying functional groups?
IR spectroscopy is useful for identifying function groups. NMR has limited utility in this area
133
Do symmetrical stretches exhibit an IR absorption signal?
No, Symmetrical stretches do no exhibit an IR absorption signal
134
T/F: NMR spectroscopy can be used to identify distinct 1H protons in a molecule
True
135
How many different NMR peaks (doublets, triplets, etc) would appear if the molecule being analyzed were:
Ethane
1 singlet
136
How many different NMR peaks (doublets, triplets, etc) would appear if the molecule being analyzed were:
Propane
1 septet (7) and 1 triplet
137
How many different NMR peaks (doublets, triplets, etc) would appear if the molecule being analyzed were:
1,3- dichloropropane
1 quintet (5) and 1 triplet
138
How many different types of equivalent protons are there in 1-bromo-2-chloropropane
There are 3 different types of equivalent protons in 1-bromo-2-chloropropane
139
T/F: NMR can make use of both 12C and 13C
False, 12C has no magnetic moment and therefore, cannot be used in NMR spec
140
What type of spectroscopy is ideal for the study of conjugated olefins?
UV-vis spectroscopy is ideal for the study of conjugated olefins
141
What type of spectroscopy can determine the molecular weight of a compound?
Mass spectroscopy determines the molecular weight of a compound
142
T/F: Monosaccharides undergo many of the same reactions as alcohols
True
143
What is the general formula for calculating the maximum number of possible stereoisomers of a molecule?
The general formula is 2^n where n=number of chiral centers
144
A pyranose has how many members in its ring?
A pyranose has a six-member ring
145
A furanose has how many members in its ring?
A furanose has a five-member ring
146
T/F: When converting a Fischer Projection to a Haworth (ring) Projection, groups on the right side of a Fischer Projection will be pointing upward
False, groups on the right side of a Fischer Projection end up pointing downward in a Haworth Projection
147
What monosaccharides maek up a molecule of maltose?
Maltose is composed of two molecules of glucose
148
Does cellulose contain β-1,4 glycosidic bonds or α-1,4 glycosidic bonds?
Cellulose contains β-1,4 glycosidic bonds
149
Do starch and glycogen contain β-1,4 glycosidic bonds or α-1,4 glycosidic bonds?
Starch and glycogen contain α-1,4 glycosidic bonds
150
What is mutarotation?
Mutarotation is the spontaneous change of configuration about the C1 that occurs when monosaccharides are exposed to water
151
T/F: Glucose is an aldohexose
True
152
T/F: Fructose is an aldopentose.
False, fructose is ketohexose
153
What is a reducing sugar?
A reducing sugar is any monosaccharide with a hemiacetal ring
154
T/F: The alpha carbon is chiral in all amino acids
False, glycine's alpha carbon has 2 hydrogens and is therefore not chiral
155
What is a zwitterion?
A zwitterion is a species with both a positive and negative charge
156
Define amphoteric
An amphoteric species can act as either a base or an acid
157
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?
The amino acid will have a net POSITIVE charge and therefore will move towards the CATHODE
158
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?
The amino acid will have a net NEGATIVE charge and therefore move towards the ANODE
159
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?
The amino acid is at its isoelectric point and will not move
160
T/F: The buffering capacity of an amino acid is greatest at its isoelectric point
False, the buffering capacity of an amino acid is least at its isoelectric point. It is greatest at its two or more pKa's
161
Where are non-polar amino acids usually found in a protein and why?
non-polar amino acids are usually found in the interior of a protein because they are hydrophobic
162
Where are polar amino acids usually found in a protein?
Polar amino acids are usually found on the exterior of a protein
163
What is the net charge of an acidic amino acid at physiological pH
The net charge of an acidic amino acid at physiological pH is negative
164
What is the net charge of a basic amino acid at physiological pH?
The net charge of a basic amino acid at physiological pH is POSITIVE
165
What type of bond joins amino acids?
a peptide bond joins amino acids together
166
Define the primary structure of a protein
Primary structure refers to the sequence of amino acids
167
Define the secondary structure of a protein
Secondary structure refers to hydrogen bond interactions within the protein
168
What are the two most common types of secondary structure?
The two most common types of secondary structure are α-helix and β-pleated sheet
169
Define tertiary structure
Tertiary structure refers to the three-dimensional folding of a protein.
170
What are the two primary classifications (regarding tertiary structure) of proteins?
Fibrous and globular proteins
171
Define quaternary structure
Quaternary structure only exists in proteins with more than one polypeptide subunit. It refers to the way the subunits arrange themselves
172
What is a conjugated protein
A conjugate protein is a protein that derives part of its function from a prosthetic group
173
What happens when a protein denatures? What can cause a protein to denature?
A protein loses its three-dimensional shape when it denatures. Changes in temperature, pH, and solute concentration can cause denaturation.
174
What is the difference between an ester and an ether?
ESTER = think carbonyl bonded to another O
Ether: batman wing. 1 O in middle of 2 R groups
175
Careful: aromatic vs anti-aromatic vs aliphatic
aromatic = planar, conjugated, follows 4n+2 Huckel's rule.
anti-aromatic = 4n
aliphatic = any non-aromatic compound!
