Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

CHM 241 Dr. Erb > Exam 2 > Flashcards

Exam 2 Flashcards

(101 cards)

Start Studying
1
Q

Ka

A

equilibrium constant for the reaction between an acid and water, tells us how many reactants are going to products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Ka value range

A

10^-50 to 10^10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how to get pKa from Ka

A

-log(Ka)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

range of pKa values

A

-10 to 50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

relationship between Ka and pKa

A

indirect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what do small or large pKa’s indicate?

A

small pKa=stronger acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

tendency of strong acids

A

they really want to give away a proton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

acidity/basicity of alcohols

A

very basic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

acidity/basicity of amines

A

almost almost basic unless theyre cations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

pattern of strength of conjugate acids

A

strong acids result in weaker conjugate bases and vice versa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

which acid will equilibrium favor and why?

A

formation of the weaker acid because it has a more stable base, so it goes from stronger to weaker acids, the acid with the most stabilized negative charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how can you find the difference in number of molecules and products?

A

subtracting the pKa’s: the result it the exponent of 10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Ka of a reaction that is likely to happen

A

large Ka

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

arrows in an acid/ base reaction

A

2 arrows, one starting at a lone pair and another starting at a bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

which acids/bases will always be on the same side of the equilibrium and why?

A

the strong acids and bases are always on the same side, opposite from the weak acids and bases due to the driving force for stronger acids to become more stable and less reactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

direction of reaction in terms of pKa

A

low to high pKa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what role does resonance play in stability

A

resonance is a stabilizing factor because it delocalizes pi electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

A in ARIO

A

Atom: the type of atom carrying a charge. When looking across the periodic table, the more electronegative atom that has the negative charge is more stable. When going down the periodic table, the larger atoms are better able to stabilize electron density. Stability indicates strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

which atoms are better at stabilizing negative charges?

A

more electronegative atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

why are larger atoms better at stabilizing electron density?

A

it can spread out the density more among its larger area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

R in ARIO

A

Resonance stabilizes formal nergative charges. more resonance = stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how does localization relate to stability?

A

indicates stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

I in ARIO

A

Induction: stabilizes a negative formal charge by spreading it out. indicated by electronegativity differnces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

induction vs resonance

A

induction is the pulling of electrons through sigma bonds, resonance moves electrons through a pi system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
why is resonance more stabilizing than induction?
resonance pulls electrons through pi systems whereas induction occurs in sigma bonds
26
O in ARIO
Orbital: type of orbital affects the stability of a formal charge. SP orbitals are the most electronegative because they have the most S character and are closest to the nucleus, and therefore more stable
27
relationship between orbitals and energy level and stability
more s character=lower energy level and more stable
28
What does ARIO tell you?
which molecule has the lower pKa
29
biggest ARIO exceptions
alkynes vs amines: where N- is less important than the orbital(ARIO out of order), then acetylene vs ammonia
30
trends in charged conjugate bases
other than HCl and H2SO4, neutral conjugate bases will be more stable than a negatively charged conjugate base
31
charges of acids and bases
Bases: neutral or negative Acids: neutral or positive
32
What outweighs A in ARIO?
charges
33
counterions
spectator ions
34
lewis acid/base definition
Acid: accepts electron pair Base: donates a pair of electrons acids dont always fit bronsted lowry defintion
35
why are lewis acids and bronsted acids sometimes different?
lewis acids include compounds with unfilled valence orbitals
36
saturated hydrocarbons
dont contain pi bonds, not very reactive
37
-ane
suffix for saturated hydrocarbons
38
which prefixes are ignored with ordering alphbetically
iso- and cyclo-
39
how do you know which parent chain to pick if there are 2 that are the same length?
choose the one with the most substituents, if substituents are the same either one is fine
40
1 carbon atom prefix
meth
41
2 carbon atom prefix
eth
42
3 carbon atom prefix
prop
43
4 carbon atom prefix
but
44
5 carbon atom prefix
pent
45
6 carbon atom prefix
hex
46
7 carbon atom prefix
hept
47
8 carbon atom prefix
oct
48
9 carbon atom prefix
non
49
10 carbon atom prefix
dec
50
suffix for substituent side chains
-yl
51
where do the numbers come from when naming substituents?
which number carbon they come from
52
how do you number a parent chain?
If one substituent is present: number the parent chain so that the substituent has the lowest locant possible If multiple substituents: number the parent chain to give the first substituent the lowest number possible If there is a tie: give second locant lowest # possible if all locants are tied: give lowest locant to substituent that comes first in the alphabet
53
how does cyclo- get alphabetized when naming molecules?
according to "C", not the substituent name
54
what is the fastest way to identify if 2 molecules are identical or not?
name them
55
conformation
differential rotations of the same molecule due to single bonds
56
what is misleading about molecules drawn on paper?
they are not stagnant. They are always rotating, vibrating, stretching or in other motion
57
What points of view do you get from wedge-and-dash structures, sawhorse structures and newman projections?
Wedge and dash: from the side Sawhorse: rotates the molecule from the side Newman: looks at a molecule head-on, straight down a C-C bond
58
Where are wedges and dashes drawn in Newman projections
always on the same side of the bond
59
Which conformations are most/least stable and why?
staggered conformation is the most stable because the dihedral angle gives maximum separation between bonds and electrons pairs that are repelling each other.
60
Torsional angle
60 staggered conformation angle, most stable and lowest energy
61
torsional strain
raises energy and decreases stability of a molecule because it takes more energy to keep the smaller bond angles together since electrons repel each other. also can be defined as the difference in energy between staggered and eclipsed formations
62
eclipse formation
0 degree bond angles, highest possible newman projection energy figure, perfect overlap, has torsional strain
63
how are are the staggered and eclipsed forms related to each other in ethane?
they are degenerate
64
hyperconjugation
An occupied bonding MO and an unoccupied antibonding MO overlap and the opposite charge difference is diffused, stabilizing the molecule. not a large stabilization
65
does H or C have a higher electronegativity?
C
66
where do wedges go on Newman projections?
the right side
67
steric strain
a type of strain resulting from groups bumping into each other, staggered and eclipse formation can have steric strain
68
what decides magnitude of steric strain?
size of colliding molecules
69
gauche interaction
type of steric strain in staggered formations
70
anti group
group where methyl groups are as far apart as possible, most stable steric strain, have no torsional strain or steric strain
71
why do anti group have no torsional strain?
it is staggered
72
Why do staggered groups have no steric stain?
methyl's are too far apart, no Gauche
73
what kind of strain is an overlap of two H's?
torsional strain
74
what kind of strain is overlap of an H and CH3
torsional strain and an insignificant amount of steric agree
75
what kind of strain are gauche interactions?
steric strain only
76
how does strain affect the energy of a molecule
it raises the energy of the molecule
77
angle strain
molecules that can't get close to their ideal bond angle, straining the bonds, unique to rings, comes from poor orbital overlap
78
most stable form of cycloalkanes
not flat to optimize bond angles
79
what type of angle strain is in smaller rings?
they are more compressed/pushed together than they would like to be
80
What type of angle strain is in larger rings?
they are wider than they want to be
81
which rings have the least angle strain?
5 and 6 C rings, 6(cyclohexane) specifically
82
what type of strain does a flat ring worsen?
increase torsional and angle strain
83
what allows benzene rings to be flat?
the atoms are SP2
84
Why are big rings more stable than smaller rings(except for 5 and 6 C rings)?
big rings have more opportunity to orient themselves to optimize bonds
85
cyclopropane
highly reactive, has severe angle and torsional strain, eclipsed, nearly flat because of restriction of having only 3 carbons
86
cyclobutane
significant angle strain and some torsional strain, eclipsed
87
cyclopentane
very little angle strain, has 1 C atom where torsional strain occurs
88
envelope formation
ideally stable formation of cyclopentane where 1 C atom is elevated upwards
89
what makes cyclohexane slightly more stable than cyclopentane?
cyclopentane has the torsional strain in 1 C atom that cyclohexane does not have
90
what characteristic makes rings good antibiotics?
they are more ready to burst/open up easily
91
chair conformation
optimally stable conformation of cyclohexane with zero angle strain
92
What is required for no angle strain?
109.5 degree bond angles
93
what is required for no torsional strain?
all adjacent C-H bonds must be staggered
94
how do you know which direction to draw axial substituents?
draw them in the direction their angle points
95
what happens when a ring flips?
everything that is axial becomes equitorial and vice versa, ONLY C-C double bonds rotate
96
why do equitorial formation tend to be more stable?
axial groups are closer together so anything bigger than an H causes steric strain
97
explain the name 1, 3-diaxial strain
the steric straining substituents interact with substituents that are 3 carbons away
98
what type of interactions is a 1,3-diaxial strain
gauche interaction between two non-H groups
99
what type of interaction is a substituent in am equatorial position?
anti interaction
100
What decides the amount of steric strain between 2 groups?
size, larger groups crowd more
101
how do you know which proton is the most acidic in a molecule?
the most acidic protein creates the most stable base when it is removed

CHM 241 Dr. Erb (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions