Organic Chemistry Flashcards
(203 cards)
1
Q
(T/F) A pi bond can exist without a sigma bond
A
False, a pi bond cannot exist independently of a sigma bond
2
Q
Which type of bond (pi or sigma) is stronger?
A
A sigma bond is generally stronger than a pi bond
3
Q
What is the hybridization of the carbon atom in CH4? What are the bond angles?
A
sp3, 109.5º
4
Q
What is the bond angle between sp hybridized atoms?
A
180º
5
Q
What is the bond angel between sp2 hybridized atoms?
A
120º
6
Q
What is the general formula of a noncyclic alkane?
A
The general formula of an alkane is CnH2n+2
7
Q
How many other carbons are 1’, 2’, 3’, and 4’ carbons bonded to?
A
1, 2, 3, and 4 other carbons respectively
8
Q
How does increasing molecular weight affect the boiling point and melting point of an alkane
A
Increased molecular weight results in increased boiling and melting points
9
Q
How does increased branching affect the boiling boil of an alkane
A
Increased branching lowers the bowling point
10
Q
What are the three steps of a halogenation reaction?
A
Initiation, Propagation, and Termination
11
Q
What does X2 –> (hv or ^) 2X• represent?
A
Initiation
12
Q
what does 2X2• —> X2 represent?
A
Termination
13
Q
What does R• + X2 –> RX + X• represent?
A
Propagation
14
Q
What does X• + R• –> XR represent?
A
Termination
15
Q
What does X• + RH –> HX + R• represent?
A
Propagation
16
Q
What does 2R• –> R2 represent?
A
Termination
17
Q
What is the order of free radical stability?
A
3º > 2º > 1º > methyl
18
Q
What type of reaction involves breaking down large alkanes into smaller ones?
A
Prolysis or “cracking” uses heat to break down large alkanes into smaller ones
19
Q
What are the products of the complete combustion of an alkane?
A
The complete combustion of an alkane produces: CO2, H2O, and heat
20
Q
Is a nucleophile electron rich or electron poor?
A
A nucleophile is electron rich
21
Q
All else being equal, how does basicity affect he strength of a nucleophile?
A
The stronger the base, the stronger the nucleophile
22
Q
How many steps are involved in an SN1 reaction? What are they?
A
There are two steps in an SN1 reaction.
- the molecule dissociates into a carbocation and a leaving group
- the nucleophile combines with the carbocation
23
Q
What is the order of carbocation stability?
A
3º > 2º > 1º > methyl
24
Q
Which step in an SN1 reaction is the rate determing step?
A
The first step, the formation of the carbocation, is the rate determing step
25
(T/F) The rate of an SN1 reaction is dependent on the concentration of the nucleophile
False, the rate is only dependent on the concentration of the original molecule
26
How can SN1 reaction rate be increased?
1. Stablilize the carbocation by increasing substitution and using a highly polar solvent
2. Use a better leaving group (weak base)
27
How does basicity affect the nature of a leaving group?
The weaker the base, the better the leaving group
28
How many steps are involved in an SN2 reaction?
SN2 reactions have one step
29
Is the rate of an SN2 reaction dependent on the concentration
The SN2 reaction rate is dependent on the concentration of both the substrate and the nucleophile
30
(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
31
(T/F) SN2 reactions involving a chiral substrate result in an inverted, optically active product
True
32
Which type of reaction is favored (SN1 or SN2) given the folowing conditions:
1. Polar protic solvent
2. Polar aprotic solvent
3. Methyl or 1º alkyl halide
4. 3º alkyl halide
1. Polar protic solvents favor SN1
2. Polar aprotic favor SN2
3. Methyl or 1º alkyl halides favor SN2
4. 3º alkyl halides favor SN1
33
Which form of an alkene has a higher melting point (cis or trans)?
trans due to symmetry
34
Which form of an alkene has a higher boiling point (cis or trans)?
cis
35
How many steps are there in an E1 elimination reaction?
There are 2 steps
36
How many steps are there in an E2 elimination reaction?
1 step
37
(T/F) E1 and SN1 reactions are driven by the same factors (polar solvent, good leaving groups, highly branched chains)?
True
38
(T/F) In the case of E2, the least substituted double bond is usually formed preferentially
False, E2 reactions favor the formation of highly substituted double bonds
39
What is Markovnikov's rule?
Protons will add to the less substituted carbon of a double bond to create a more stable carbocation intermediate
40
Would the electrophilic addition of Br2 to an alkene result in syn or anti addition?
The Br2 would undergo anti addition
41
(T/F) The reduction of an alkyne on a metal surface (Pd) results in a cis alkene
False. It results in an alkane
42
(T/F) The reduction of an alyne in Na and NH3 produces a trans alkene
True
43
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
44
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
45
What is an aromatic compound?
A aromatic compound is defined as any unusually stable ring system. Aromatic compounds are cyclic, conjugated polyenes that follow Hückel's rule
46
What is an aliphatic compound?
An aliphatic compound is any non-aromatic compound
47
What is Hückel's rule?
Hückel's rule states that an aromatic compund has (4n+2)π electrons, where n is an nonnegative integer
48
What is antiaromatic compound?
An antiaromatic compound is a cyclic conjugated polyene with 4n electrons
49
What is the difference between a phenyl and a benzyl group?
A benzene ring acting as a substituent is call a phenyl group (-C6H5). A tolune molecule substituted at the methyl position is called a benzyl- group (-CH2C6H5)
50
Do electron donating groups activate or deactivate an aromatic ring?
Electron donating groups activate a ring
51
How do electron withdrawing groups affect the reactivity of an aromatic ring?
Electron withdrawing groups deactivate a ring
52
Is COOH activating/ deactivating and ortho/para or meta directing?
Deactivating / meta
53
Is NR2 activating/ deactivating and ortho/para or meta directing?
Activating/ ortho-para
54
Is NH2 activating/ deactivating and ortho/para or meta directing?
Activating / ortho-para
55
Is NO2 activating/ deactivating and ortho/para or meta directing?
Deactivating / meta
56
Are F, Cl, Br, I activating/ deactivating and ortho/para or meta directing?
Deactivating / ortho-para
57
Is COOR activating/ deactivating and ortho/para or meta directing?
Deactivating / meta
58
Is OR activating/ deactivating and ortho/para or meta directing?
Activating / ortho-para
59
Is SO3H activating/ deactivating and ortho/para or meta directing?
Deactivating / meta
60
Is OCOR activating/ deactivating and ortho/para or meta directing?
Activating / ortho-para
61
CH3 activating/ deactivating and ortho/para or meta directing?
Activating / ortho-para
62
(T/F) Activating compounds are always o-p directors?
True
63
(T/F) Deactivating compunds are always meta directors
False, halogens are deactivating and are o-p directing
64
Why do alcohols have a significantly higher boiling point than analogous alkanes?
Alcohols can hydrogen bond
65
(T/F) Phenols are less acidic than aliphatic alcohols
False, phenols are much more acidic than aliphatic alcohols
66
What are three types of reactions used to synthesize alcohols?
Addition, Substitution, and Reduction
67
Can a tertiary alcohol be easily oxidized?
No, tertiary alcohols cannot be oxidized without cleavage of a carbon-carbon bond
68
Can ethers hydrogen bond?
No, ethers do not hydrigen bond
69
(T/F) Straight chain ethers can be cleaved under high temperature in the presence of HBr or HI
True
70
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
71
How is a ketone or an aldehyde from an alcohol?
Oxidizing an alcohol will produce the corresponding ketone or aldehyde (ie by using PCC or Na2Cr2O7)
72
How do you produce a ketone or aldehyde from an alkene?
Ozonolysis of an alkene will produce corresponding ketons or aldehydes as cleavage products
73
Which protons relative to a carbonyl group are acidic?
Alpha protons relative to a carbonyl group are slightly acidic
74
What happens when aldehydes or ketons react with water?
Aldehydes adn ketons react with water to form gemdiols
75
(T/F) A reaction in which two molecules combine with the loss of a water molecule is a condensation reaction
True
76
What would be the product when acetaldehyde is reacted with dilute NaOH?
aldol
77
What is the name of the reaction when acetaldehyde is reacted with dilute NaOH?
Aldol condensation
78
What are the common names for the first three straight chain carboxylic acids?
The first three carboxylic acids are: formic acid, acetic acid, and propionic acid
79
(T/F) Alcohols have higher boling points than carboxylic acids
False, carboxylic acids have higher boiling points than corresponding alcohols
80
How do electron withdrawing groups (-Cl, -NO2) attached to the alpha carbon affect the acidity of the carboxylic acid?
Electron withdrawing groups increase acidity
81
How do electron donating groups (-NH2, -OCH3) attached to the alpha carbon affect the acidity og a carboxylic acid?
Electron donating groups decrease acidity
82
What type of alcohol (1º, 2º, 3º) can be oxidized to carboxylic acid?
1º alcohols can be oxidized to carboxylic acids, however 2º and 3º alcohol cannot
83
What is a micelle? Is the interior hydrophobic or hydrophillic?
When placed in an aqueous solution, soap molecules arrange themselves into spherical structures called micelles. The soap molecules arrange themselves such that their polar heads face outward and their nonpolar chains face inward
84
Would you have to oxidize or reduce a carboxylic acid to prepare an alcohol?
Reduction of a carboxylic acid forms an alcohol
85
(T/F) Acid chlorides are very reactive
True
86
How do electron donating groups affect the acidity of benzoic acid?
Electron donating groups reduce the acidity of benzoic acid
87
How do electron withdrawing groups affect the acidity of benzoic acid?
Electron withdrawing groups increase the acidity benzoic acid
88
(T/F) Anhydrides react under the same conditions as acid chlorides
True
89
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
90
What are the products for the hydrolysis of an ester?
The products are a carboxylic acid and an alcohol
91
What is saponification?
Saponification is the process whereby fats are hydrolyzed, under basic conditions, to produce soaps
92
What is transesterification?
C-CO-OR' + R"OH \<-\> C-CO-OR" + R'OH
93
(T/F) A glycerol molecule attached to two carboxylic acids and one phosphoric acid is a phospholipid
True
94
Name: CH3CH2NH2
Ethylamine (common) or ethanamine (IUPAC)
95
Name: CH3CH2CH2CH2N(CH3)2
N,N-dimethylbutylamine (common) or N,N-dimethylbutanamine (IUPAC)
96
How many alkyl groups are in a tertiary (3º) amine?
A 3º amine has 3 alkyl groups attached to the nitrogen
97
What is a quaternary ammonium compound?
A 4º ammonium coupound is a ntrogen atom attacked to 4 alkyl gorups. The nitrogen is positively charded and, therefore, the compound exists as a salt
98
(T/F) An imine is a compound with a carbon-nitrogen double bond
True
99
Which types of amines can form hydrogen bonds (1º, 2º, 3º)
1º and 2º amines can form hydrogen bonds
100
(T/F) Axial hydrogens are parallel to the ring
False, axial hydrogen are perpendicular to the ring
101
(T/F) Bulky groups prefer the equatorial position over the axial group
True
102
what are geometric isomers?
Geometric isomers are molecules that differ with respect to the spatial relationship of substituents around a double bond
103
What is a chiral molecule?
A chiral molecule is a molecule that is not superimposable upon its mirror image
104
What are enantiomers?
Enantiomers are chiral molecules that are non-superimposable mirror images of each other
105
(T/F) Achiral molecules are optically active
False, achiral molecules are optically inactive
106
What is a dextrorotatory (+) compound?
A dextrorotatory compound rotates polarized light to the right (clockwise)
107
What type of chemical bond involves the sharing of electrons?
Covalent bonds involve the sharing of electrons
108
What type of chemical bond involves the sharing of electrons?
Covalent bonds
109
What type of chemical bond involves the transfer of electrons?
Ionic bonds
110
What orbital has a spherical shape?
"s" orbitals are spherically shaped
111
What orbital has a bi-lobed shape?
"p" orbitals are bi-lobed
112
What are the prefixes of the first 12 alkanes?
Meth, Eth, Prop, But, Pent, Hex, Hept, Oct, Non, Dec, Undec, Dodec
113
What are the 5 steps used to name alkanes according to IUPAC rules?
1. Find the longest chain
2. Number the chain so that the lowest set of numbers is obtained for the substituents
3. Name and alphabetize the subst.
4. Assign a number to each subst.
5. Complete the name
114
What are the 5 steps used to name alkenes according to IUPAC rules?
1. Find the longest chain containing the double bond
2. Number the chain so that the double cond receives the lowest possible number
3. Name and alphabetize subst.
4. Specifiy the configurational isomer
5. Name the compound
115
What is the common name for ethyne?
Ethyne is commonly known as acetylene
116
In the case of an"en-ol" which carbon receives the lowest number?
The carbon attached to the alcohol group is assigned the lowest number
117
What is a diol?
A diol is a molecule with two hydroxyl (OH) groups
118
(T/F) An aldehyde has a carbonyl group somewhere in the middle of the carbon chain
False. In an aldehyde, the carbonyl group is at the end of the carbon chain
119
(T/F) A ketone has the carbonyl group at one end of the carbon chain
False. In a ketone, the carbonyl group is somewhere in the middle of the carbon chain
120
In the case of an "en-one" which carbon receives the lowest number?
The carbonyl carbon receives the lowest number
121
What type of compound does a -COOH group denote?
The COOH group denotes a carboxylic acid
122
What are the common names for the following:
1. methanoic acid
2. ethanoic acid
3. propanoic acid
1. formic acid
2. acetic acid
3. propionic acid
123
Name the functional group: RSN
Thiol
124
Name the functional group: R2S
Sulfide
125
Name the functional group: RNO2
Nitro
126
Name the functional group: RN3
Azide
127
Name the functional group: RN2+
Diazo
128
Name the prefix and suffix: Carboxylic acid
carboxy- / -oic acid
129
Name the prefix and suffix: Ester
alkoxycarbonyl- / -oate
130
Name the prefix and suffix: Acyl Halide
halocarbonyl- / -oyl halide
131
Name the prefix and suffix: Amide
amido- / -amide
132
Name the prefix and suffix: Nitrile
cyano- / -nitrile
133
Name the prefix and suffix: Aldehyde
oxo- / -al
134
Name the prefix and suffix: Ketone
oxo- / -one
135
Name the prefix and suffix: Alcohol
hydroxy- / -ol
136
Name the prefix and suffix: Thiol
sulfhydryl- / -thiol
137
Name the prefix and suffix: Amine
amino- / -amine
138
Name the prefix and suffix: Ether
alkoxy- / -ether
139
Name the prefix and suffix: Sulfide
alkylthio- / -sulfide
140
Name the prefix and suffix: Nitro
nitro- / ~
141
Name the prefix and suffix: Azide
azido- / -azide
142
Name the prefix and suffix: Diazo
diazo- / ~
143
What is a structural isomer?
Structural isomers have the same chemcial formulas, but different atomic connectivity
144
What is a stereoisomer?
Stereoisimers are compunds that differ only in respect to the spatial arrangement of their atoms
145
Order the following conformation of n-butane according to energy levels (low to high): gauche, anti, eclipsed, totally eclipsed
Anti, gauche, totally eclipsed
146
What are the three cyclic hexam conformers in order of energy levels (low to high)
Chair, twisted, boat
147
What is a levorotatory (-) compound?
A levorotatory compound rotates polarized light to the left (counterclockwise)
148
What is a recemic mixture?
A racemic mixture contains equal amounts of both enantiomers
149
How many stereoisomers are possible for a molecule with four chiral centers?
A racemic mixture contains equal amounts of both enantiomers
150
How many stereoisomers are possible for a molecule with four chiral centers?
24 = 16
151
What are diastereomers?
Diastereomers are stereoisomers that are not mirror images of each other
152
What types of molecules are optically active?
Chiral molecules
153
What is a meso compound?
A meso compound is a molecule that possess stereocenters but has a plane of symmetry. It is achiral and therefore optically inactive
154
(T/F) All single bonds are sigma bonds?
True
155
What type of bond results when two p orbitals overlap?
Two overlapping p orbitals for a pi bond
156
What are the components of a double bond
A double bond is composed of 1 sigma and 1 pi bond
157
What are the compondents of a triple bond?
A triple bond is composed of 1 sigma and 2 pi bonds
158
Which purification technique involves a solif turning directly into a gas?
Sublimation
159
What separation technique makes use of two immiscible solvents?
Extraction
160
What seperation technique can be used to isolate a solid from a liquid?
Filtration
161
(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
162
Which separation technique can be used to separate a mixture of particiles with different densities and masses?
Centrifugation
163
Which separation technique takes advantage of a solution containing two or more compunds with different boiling points?
Distillation
164
(T/F) Vacuum distillation can be used to seperate liquids with very high boiling points
True
165
Which separation technique separate compounds based upon their different affinities for a medium?
Chromatogrpahy
166
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
167
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
168
Which separation technique uses an electric field?
Electrophoresis
169
SDS-polyacrylamide gel electrophoresis sepatates proteins based on what factor?
Based on their masses
170
(T/F) Agarose gel electrophoresis is used to separate fragments of nucleic acid
True
171
What type of spectroscopy is useful for identifying functional groups?
IR is useful. NMR has limited utility in this area.
172
Do symmetrical stretches exhibit an IR absorption signal?
No
173
(T/F) NMR spectroscopy can be used to identify distinct 1H protons in a molecule
True
174
How many different NMR peaks (doublets, triplets, etc) would appear if the molecule being analyzed were:
Ethane
Propane
1,3-dichloropropane
Ethane - 1 singlet
Propane - 1 septet (7) and 1 triplet
1,3-dichloropropane - 1 quintent and 1 triplet
175
How many different types of equivalent protons are there in 1-bromo-2-chloropropane?
There are three different types of equivalent protons
176
What type of spectroscopy is ideal for the study of conjugated olefins?
UV-vis spectroscopy is ideal
177
What type of spectroscopy can determine the molecular weight of a compound?
Mass spectroscopy determines the molecular weight of a compound
178
What is the general formula for a carbohydrate?
Cn(H2O)m
179
(T/F) Monosaccharides undergo many of the same reactions as alcohols
True
180
What is the general formula for calculating the maximum number of possible stereoisomers of a molecule?
The general formula is 2n where n = number of chiral centers
181
(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
182
What monosaccharides make up a molecule of maltose?
Maltose is composed of two molecules of glucose
183
Does cellulose contain ß-1,4 glycosidic bonds or a-1,4 glycosidic bonds
Cellulose contains ß-1,4 glycosidic bonds
184
Do starch and glycogen contain ß-1,4 glycosidic bonds of a-1,4 glycosidic bonds?
Starch and glycogen contain a-1,4 glycosidic bonds
185
What is mutarotation?
Mutarotation is the spontaneous change of configuration about C1 that occurs when monosaccarides are exposed to water
186
(T/F) Glucose is an aldohexose
True
187
(T/F) Fructose is an aldopentose
False, fructose is a ketohexose
188
What is a reducing sugar?
A reducing sugar is any monosaccharide with a hemi-acetal ring
189
(T/F) The alpha carbon is chiral in all amino acids
False, glycine's alpha carbon has 2 hydrogens and is therefore not chiral
190
What is a zwitterion?
A zwitterion is a species with both a positive and a negative charge
191
Define amphoteric
An amphoteric species can act as either a base or an acid
192
In what direction will an amino acid with a neutral side chain move during electrophoresis at pH 4:
1. If the pI of the amino acid is 7?
2. If the pI of the amino acid is 3?
3. If the pI of the amino acid is 4?
1. The amino acid will have a net positive charge and, therefore, move toward the cathode
2. The amino acid will have a net negative charge and, therefore, move towards the anode
3. The amino acid is at its isoelectric point and will not move
193
(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
194
Where are nonpolar amino acids usually found in a protein and why?
nonpolar amino acids are usually found in the interior of a protein because they are hydrophobic
195
What is the net charge of a basic amino acid at physiological pH?
The net charge of a basic amno acid at physiological pH is positive
196
What type of bond joins amino acids?
a peptide bond joins amino acids together
197
Define the primary structure of a protein
Primary structure refers to the sequence of amino acids
198
Define secondary structure
Secondary structure refers to hydrogen bond interactions within the protein
199
What are the two most common types of secondary structure?
The two most common types of secondary structure are a-helix and ß-pleated sheet
200
What are the two primary classifications (regarding tertiary structure) of proteins?
Fibrous and globular proteins
201
Define quaternary structure
quarternary structure only exists in proteins with more than one polypeptide subunit. If refers to the way the subunits arrange themselves
202
What is a conjugated protein?
A conjugated protein is a protein that derives part of its fucntion from a prosthetic group
203
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
