Definitions Flashcards
(174 cards)
1
Q
What role do carbonyls play in reactions?
A
electrophiles (C)
2
Q
define ionic bond
A
attractive force between oppositely charged ions
2
Q
What are the possible values of an electron’s spin quantum number?
A
+/- 0.5
2
Q
What is the general structure of a carboxylic acid?
A
2
Q
What does a wedge bond denote?
A
- bond projecting out of the paper toward the reader
2
Q
define atomic number
A
protons in an atom’s nucleus
2
Q
What is the geometry of formaldehyde?
A
trigonal planar
2
Q
Label the ortho, meta, para positions to the methyl group
A
2
Q
What is the hybridization of a carbonyl carbon?
A
sp2
2
Q
define anomeric Carbon
A
C in a cyclic acetal that is attached to 2 O’s
3
Q
define secondary C
A
- directly attached to only 2 other carbons
3
Q
define glycoside
A
carbohydrate in which the anomeric -OH group has been replaced by an alkoxy group (-OR)
3
Q
define wax
A
mixtures of substances that usually contain esters of fatty acids & long-chain alcohols
4
Q
define hybrid orbitals
A
- orbitals formed from by mixing (hybridizing) valence orbitals of equal energy
4
Q
define elementary step
A
- involves only 1 transition state
4
Q
What is the definition of oxidation & reduction in terms of organic chemistry?
A
- oxidizing = adding C-O bonds
- reducing = reducing C-O bonds
4
Q
Which are stronger acids, carboxylic acids or alcohols? Why?
A
Carboxylic acids for 2 reasons:
- Inductive effect: electron-withdrawing power of carbonyl group (stabilizes conjugate base by attracting electrons away from negatively charged O)
- Resonance effect: negative charge in carboxylate anion is delocalized (resonance stabilization of conjugate base)
more stable conjugate base => weaker conjugate base & more likely to form => stronger acid
5
Q
define alkane
A
- hydrocarbon with all single bonds
5
Q
What is another name for basic hydrolysis of esters?
A
saponification
5
Q
What configurations are possible at the anomeric C?
A
alpha (-OH above ring) or beta (-OH below ring)
7
Q
What is the geometry of NH3?
A
trigonal pyramidal
(N has an extra pair of electrons)
8
Q
What is the general structure of an enol?
A
8
Q
define branched-chain carbohydrate
A
carbohydrate that has a C substituent attached to the main chain
9
Q
define valence electrons
A
- outermost electrons of an atom
9
define aldose
carbohydrate containing an aldehyde group
10
define amino sugar
a -OH group in a carbohydrate is replaced by an amine group
10
What is the physical difference between fats & oils?
* fats = solid at room temp
* oils = liquid at room temp
11
What compounds can carboxylic acids be reduced to?
primary alcohols
12
Which elements have a complete octet of electrons in their valence shell?
noble (rare) gases
13
# define covalent bond
shared electron pair
14
Which carbonyl group is more stable, that of a carboxylic acid or ketone/aldehyde and why?
Carboxylic acid due to additional resonance stabilization from -OH group
15
# define steric hindrance (van der Waals strain)
* destabilization of a molecule from 2 of its atoms being too close to each other
16
How is a Grignard reagent formed?
17
# define Hund's rule
* in filling orbitals of equal energy, each is singly occupied before any one is doubly occupied
17
# define constitution
* order of attachment of atoms within a molecule
18
define the Pauli exclusion principle
* 2 electrons may occupy the same orbital only when they have opposite, or "paired" spins
19
What does a dash bond denote?
* bond projecting out of the paper away from the reader
20
In an acid-base reaction, which side of the reaction equation does the position of equilibrium favor?
* the side with the stronger acid & base
20
What is the characteristic reaction of carboxylic acid derivatives?
nucleophilic acyl substitution
20
define disaccharide
carbohydrate in which 2 monosaccharides are joined by a glycoside bond
21
# define anti conformation
* angle between bonds of 2 groups of interest is 180 degrees
22
What is the most acidic class of compounds containing only C, H, O?
* carboxylic acids
23
What is the shape of s orbitals?
* spherically symmetric orbital
24
How many atoms are directly bonded to a sp hybridized C?
2
25
What is the fast step in enolization?
* water molecule acts as a Bronsted acid to transfer a proteon to the oxygen of the enolate ion
26
# define anion
* negatively charged ion
28
# define angle strain
* distortion of bond angles
(as in cyclopropane)
29
isobutane
29
What cellular structure are phospholipids a principle component?
cell membranes
30
define alkyne
* hydrocarbon containing at least one C-C triple bond
31
What effect do electronegative substituents have on the acidity of carboxylic acids?
* they increase the acidity, especially when attached to the alpha C
32
What is the eclipsed conformation of ethane?
33
define hexose
sugar with 6 C atoms
33
Most carbohydrates exist as cyclic \_\_\_\_\_\_
hemiacetals
35
# define conformation
* different spatial arrangements of a molecule that are generated by rotation about single bonds
36
The stronger the acid, the ____ the Ka
higher
37
define lipid
naturally occurring substances that are soluble in nonpolar solvents
38
Name the following structure
amide
39
# define hydrocarbon
* compounds containing only C & H
41
The stronger the acid, the ___ pKa
lower
41
What is the only reducing agent strong enough to reduce carboxylic acids?
LiAlH4 (LAH)
43
How many atoms are directly bonded to a sp3 hybridized C?
4
45
What is the defining functional group of a ketone?
a carbonyl group
46
define pyranose
cyclic acetals (carbs) with 6-membered rings
47
define gauche conformation
* angle between bonds of 2 groups of interest is 60 degrees
47
As the s character of C increases, does C become more electron-withdrawing or donating?
* withdrawing
48
What acts as the electrophile in nucleophilic acyl substitutions of carboxylic acid derivatives?
carbonyl carbon
49
define "L series" conformation of carbohydrates
* In Fisher projection, hydroxyl group at highest numbered stereogenic center is to the right
50
Where are di- & polysaccharides cleaved during hydrolysis & what are the products?
cleaved at glycoside bonds & results in monosaccharides
51
define ketose
carbohydrate containing a ketone group
53
# define tertiary C
* directly attached to only 3 other C
54
Which is more electronegative, N or O?
O
54
What effect do electronegative substituents have on the acidity of carboxylic acids?
they increase the acidity
55
define disaccharide
* can be hydrolyzed into 2 monosaccharides
56
# define H bond
* dipole-dipole interaction between H on F, O, or N (+ polarized) and F, O, or N (- polarized)
58
# define stereoisomer
* isomers that have their atoms bonded in the same order, but differ in the arrangement of their atoms in space
60
# define electron delocalization
* electron shared by several nuclei
61
# define electronegativity
* the tendacy of an atom to draw the electrons in a covalent bond towards itself
63
# define Bronsted-Lowry acid/base
* acid = proton donor
* base = proton acceptor
64
# define isomer
* different compounds with the same molecular formula
66
How is an aldol formed?
From nucleophilic addition of an enol to an aldehyde
67
define "D series" conformation of carbohydrates
* In Fisher projection, hydroxyl group at highest numbered stereogenic center is to the right
68
define furanose
cyclic acetals (carbs) with 5-membered rings
69
How many atoms are directly bonded to a sp2 hybridized C?
3
71
# define activation energy (Eact)
* minimum increase in potential energy necessary for chemical reaction to occur
72
What is the maximum number of electrons in the valence shell of any 2nd row element?
8
73
define reducing sugar
* aldoses or ketoses that contain free hemiacetal function
* i.e., capable of being oxidized
* i.e., give positive tests with Benedict's reagent (oxidizing agent)
75
# define primary C
* directly attached to only 1 other C
76
define deoxy sugar
a -OH group in a carbohydrate replaced by H
77
What types of bonds include pi bonds?
* double or triple bond
77
define polysaccharide
carbohydrate composed of many monosaccharide units connected through glycosidic linkages
79
# Define keto-enol tautomerism
* a proton-transfer equilibrium between ketones/aldehydes and enols
* tautomerism = interconversion between two structures that differ by the placement of an atom or a group
80
Rank in order of lowest to highest boiling point and justify:
Alcohols, Alkanes, Amines
Alkanes \> Amines \> Alcohols
Justification: hydrogen bonding
82
How many 2p orbitals are there?
3: x, y, z
83
What is the shape of p orbitals?
* 2 lobes (dumbbell)
84
What is the most stable conformation of cyclohexane?
chair conformation
85
What types of bonds include sigma bonds?
* single, double, triple
87
# define dipole-dipole attractions
* (+) polarized region of one molecule is attracted to (-) polarized region of another
88
What is an alkyl group? (R)
a hydrocarbon or hydrogen
89
What is an orbital?
* the regions of space near the nucleus where the electrons spend 90-95% of their time
89
What is the staggered conformation of ethane?
91
# define stereochemistry
* 3D shape of a molecule
92
What is the lowest energy electron orbital?
1s
93
# define structural (constitutional) isomer
* isomers that differ in the order in which their atoms are bonded
94
# define formal charge
* charges on atoms within compounds
96
What is a hydroxyl group?
97
What is the generic structure of an ester
99
# define polar covalent bond
* a bond in which one atom has a greater tendacy to attract electrons that the other
100
What is the geometry of carbon dioxide or N=N=N?
linear
101
What is the general structure of an ester?
102
What is the mathematical relationship between Ka and pKa?
pKa = -log10Ka
103
What is the onlyl planar cycloalkane?
cyclopropane
105
What is the general structure of a ketone?
107
What is an enolization reaction catalyzed by?
base
108
Name the following structure
ester
110
What is the generic structure of an acyl chloride
111
What are the structural characteristics of fats & oils?
glycerol esters of long-chain carboxylic acids
112
What is the order of alcohol reactivity toward hydrogen halides?
* primary least reactive
* tertiary most reactive
113
define cation
positively charged ion
114
What is the characteristic intermediate of nucleophilic acyl substitutions of carboxylic acid derivatives?
tetrahedral
115
What is the geometry of CR4?
tetrahedral
116
What is a thiol group?
117
Order the 4 carboxylic acid derivatives from most to least reactive (toward nucleophilic acyl substitution) and justify
acyl chloride \> anhydride \> ester \> amide
* justification: electron pair donation of derivative group (i.e., less electron delocalization from C & more resonance stabilization) stabilizes carbonyl group & makes it less reactive
119
What is the generic structure of an anhydride
120
# define induced-dipole/induced-dipole attractive force
* temporary distortion of electron clouds
* weak attraction
* a van der Waals force
121
Which of aldehyde, carboxylic acid, or ketone has the least electronegative carbonyl group and why?
Carboxylic acid; electron delocalization due to lone pair of electrons on hydroxyl group
122
define phospholipid
* structurally similar to triacylglycerols, with phosphate groups in the head group
123
# define resonance
* more than one Lewis structure may be written for a molecule
* true structure has an electron distribution
124
define alkene
* hydrocarbon containing at least one C=C
125
What is the slow step in enolization?
* proton abstraction by hydroxide ion from the alpha-carbon of the carbonyl
127
# define condensed structural formula
* some, many, or all bonds left out
* subscripts are used to indicate the number of identical groups attached to a particular atom
* *e.g.*, (CH3)2CHOH
128
What molecule is the C sources of most lipids?
acetic acid (acetate)
129
# define bimolecular [elementary step]
* elementary step that involves 2 molecules
130
# define quaternary C
* directly attached to 4 other C
131
In any proton-transfer process, the position of equilibrium favors formation of the ___ acid and the ___ base.
weaker, weaker
132
# define torsional strain
* stain due to the eclipsing of bonds on adjacent atoms
133
define mutarotation
* change in optical rotation
* i.e., change in cyclic acetal conformation
135
What is the least stable conformation of cyclohexane?
boat conformation
137
What is Fisher esterification
* acid-catalyzed formation of an ester from a carboxylic acid and alcohol
138
# define Lewis structure
* structural formulas in which electrons are represented as dots
139
# define concerted reaction
* reaction that proceeds by way of a single elementary step
140
What is an aldol?
aldehyde + alcohol
141
Name the following compound
Acyl chloride
142
Which is a better electron-pair donor, N or O?
N
143
What is the generic structure of an amide
144
Which atoms are halogens?
* F
* Cl
* Br
* I
145
What are the rows in the periodic table called?
periods
146
define pentose
sugars with 5 C atoms
148
What do you replace the -e ending of an alkane name with to name a carboxylic acid?
-oic acid
149
151
When drawing resonance forms, are electrons moved between bonds or between bonds and atoms?
* bonds and atoms
152
define monosaccharide
* simple carbohydrate
* cannoted by hydrolyzed/cleaved to smaller carbohydrates
153
What are the 3 important mechanistic aspects of nucleophilic acyl substitution?
1. Activation of the carbonyl group by protonation of the carbonyl oxygen
2. Nucleophilic addition to the protonated carbonyl, forming a tetrahedral intermediate
3. Elimination from the tetrahedral intermediate to restore the carbonyl group
154
What class of molecules does cholesterol belong to?
steroids
155
What forces must be overcome to vaporize (boil) a substance?
* intermolecular attractive forces
156
What is the isoprene unit?
with or without double bonds
157
hydronium (oxonium) ion
H3O+
158
What is the geometry of water?
bent
159
Name the following structure
Anhydride
160
Which have high boiling points, carboxylic acids or ketones/aldehydes and why?
Carboxylic acids due to hydrogen bonding
161
# define principal quantum number
* specifies the electron's shell and is related to the energy of the orbital
* 1s = 1 is principal quantum number
162
How are the carbons neighboring a carbonyl group named?
* alpha: adjacent to carbonyl
* beta: 2 carbons away from carbonyl
* etc.
163
What is the general structure of an aldehyde?
164
How are formal charges calculated?
* group # in periodic table - # bonds - # unshared electrons
165
What is the general structure of an acetal?
166
What is saponification?
* basic hydrolysis of esters
167
What requirement must a carbonyl compound meet in order to react with itself in aldol condensation?
* it must have an alpha H
168
The stronger the acid, the ___ the conjugate base.
weaker
169
What is the geometry of BF3?
trigonal planar
| (no extra pair of electrons)
170
What is the defining functional group on an alcohol?
a hydroxyl group
171
Rank the following groups in order of naming precedence:
* -OH
* -COOH
* -X (halogen)
* -R (alkyl)
* alkene
-COOH \> OH \> alkene \> X, R
172
# define the octet rule
* In forming compounds, elements that obey the octet rule gain, lose, or share electrons to give a stable electron configuration characterized by 8 valence electrons.
173
What is the general structure of an ether?
174
What role(s) do amines play in reactions?
base/nucleophile
