Kaplan Gen Chem Flashcards
(258 cards)
1
Q
each proton has an amount of charge equal to the fundamental unit of charge (e = …)
A
1.6 * 10^-19
2
Q
protons have a mass of about
A
one atomic mass unit
3
Q
the … (…) of an element is equal to the number of protons found in an atom of that element –> unique identifier
A
atomic number; Z
4
Q
neutrons are …, with a mass only slightly higher than that of the proton
A
neutral
5
Q
protons and neutrons together make up the majority of an atom’s …
A
mass
6
Q
… (…): sum of the protons and neutrons in the atom’s nucleus
A
mass number; A
7
Q
… have the same atomic number but different mass numbers
A
isotopes
8
Q
electrons move through the space surrounding the nucleus and are associated with varying…. They have a charge equal in magnitude but opposite in sign as protons
A
levels of energy
9
Q
mass of an 3- is about … that of a proton
A
1/2000
10
Q
… force of attraction between protons and electrons are much greater than the … force of attraction between them
A
electrostatic; gravitational
11
Q
electrons closer to the nucleus are at … energy levels, while those that are in higher electron shells have … energy
A
lower; higher
12
Q
… electrons are the furthest from the nucleus and are more likely to be involved in bonds because they experience the least electrostatic pull from the nucleus
A
valence
13
Q
size of the atomic mass unit is exactly … the mass of the … atom, about 1.66 * 10^-24 g
A
1/12; C-12
14
Q
atomic mass of an atom is nearly equal to its mass number – the sum of protons and neutrons (in reality, some mass is lost as …)
A
binding energy
15
Q
weighted average of different isotopes is referred to as the
A
atomic weight
16
Q
because half-life corresponds with …, it helps determine the relative proportions of different isotopes
A
stability
17
Q
atomic weight represents both the mass of the … atom of that element in amu and the mass of … of the element in grams
A
average; on mole
18
Q
one mole is a number of things equal to avogadro’s number, NA= …
A
6.02 *10^23
19
Q
Max Planck developed quantum theory, proposing that energy emitted as electromagnetic radiation from matter comes in discrete bundles called …
A
quanta
20
Q
energy of a quantum is given by the planck relation: E = …
h = …
A
hf;
6.626 * 10^has -34 J*s
21
Q
Bohr postulated that the centripetal force acting on the electron as it revolved around the nucleus was created by the … force between the proton and electron
A
electrostatic
22
Q
classical mechanics postulates that an object revolving in a circle may assume an infinite number of values for its … and …, implying that the … (L = mvr) and … could take on any value
A
radius; velocity;
angular momentum; kinetic energy
23
Q
Bohr’s postulations placed a limit on these values of angular momentum, which for a hydrogen nucleus he predicted would be:
L = …
n is principal quantum number
A
nh/2pi
24
Q
bohr related permitted angular momentum values to energy of an electron:
E = …
Rh is the … –> … J/electron
A
-Rh/n^2;
Rydberg unit of energy; 2.18 * 10^-18
25
bohr related permitted angular momentum values to energy of an electron:
like angular momentum, the energy of the electron changes in ... amounts with respect to the quantum number
discrete
26
bohr related permitted angular momentum values to energy of an electron:
E = -Rh/n^2
while the magnitude of the fraction is getting smaller, the actual value it represents is ... (becoming ...)
getting larger; less negative
27
electrons in any of their quantized states in the atom will have an attractive force toward the proton, which is represented by the ... in the E equation
negative sign
28
ground state of an atom is the state of ... energy
| atoms can be in an ... state where at least one electron has moved to a subshell of higher energy than normal
lowest; excited
29
electrons are not restricted to specific pathways, but tend to be ...
localized in certain regions of space
30
at room temp most atoms are
in their ground state
31
when excited electrons return to ground state, they emit discrete amounts of energy in the form of
photons
32
```
as electrons go from a lower energy level to a higher energy level, they get AHED:
....
....
...
... (from the nucleus)
```
absorb light;
higher potential
excited
distant
33
electromagnetic energy of photons can be determined by the following equation: ...
E = hc/lambda
34
c is the speed of light in a vacuum --> ...
3.00 * 10^8 m/s
35
because each element can have its electrons excited to a different set of distinct energy levels, each possesses a unique ..., which acts as an identifier for the element
atomic emission spectrum
36
group of H emission lines corresponding to transitions n>=2 to n = 1 is the ... series. n>=3 to n = 2 is the ... series and n = 4 to n = 3 is the ... series
Lyman;
Balmer;
Paschen
37
balmer series includes 4 wavelengths in the
visible region
38
Lyman has ... energy transitions than balmer and thus has ... photon wavelengths in the UV region
larger; shorter
39
energy associated with a change in the principal quantum number from a higher initial value ni to a lower final value nf is equal to the energy of the photon predicted by Planck's quantum theory:
E = hc/λ= -R_H [1/(n_i^2 )-1/(n_f^2 )]
hc/λ= -Rh [1/(ni^2 )-1/(nf^2 )]
40
E =hc/λ= -Rh [1/(ni^2 )-1/(nf^2 )]
This equation basically states that the energy of the emitted photon corresponds to the difference in energy between the ... and ...
higher energy initial state; lower energy final state
41
every element possess a characteristic ... --> wavelengths of absorption correspond to wavelengths of ... because the difference in energy between levels remains unchanged
absorption spectrum; emission
42
bohr's model was inadequate bc it didn't take into account the ... between multiple ... surrounding the nucleus
repulsion; electrons
43
electrons move rapidly and are localized within regions of space around the nucleus called ...
orbitals
44
Heisenberg uncertainty principle: it is impossible to simultaneously determine, with perfect accuracy, the ... and ... of an electron
momentum; position
45
four quantum numbers: ..., ..., ..., and ...
n; l; ml; ms
46
...: no two electrons in a given atom can possess the same set of four quantum numbers
Pauli exclusion principle
47
the position and energy of an electron described by its quantum numbers are its
energy state
48
value of n limits values of ... which limit the values of ...
l; ml
49
values of the quantum numbers describe info about the .., ..., and ... of e- orbitals
size; shape; orientation
50
principal quantum number, n, indicates the ... and ... of the electron's shell
energy level; radius
51
each shell has a capacity to hold ... electrons, where n is the principal quantum number
difference in energy between two shells ... as the distance from the nucleus increases
2n^2;
| decreases
52
second quantum number is the ... (...) quantum number, designated by l
refers to the ... and ... of subshells within a given principal energy level
azimuthal; angular momentum;
| shape; number
53
angular momentum quantum number:
| the n-value tells you the number of ... -->the range of possible values for l is ... to ...
possible subshells; 0; n-1
54
... refers to the shorthand representation of the principal and azimuthal quantum numbers
spectroscopic notation
55
the capacity to hold electrons within each subshell is: ...
4l + 2
56
magnetic quantum number, ml, specifies the particular ... within a subshell where an electron is most likely to be found at a given moment in time
orbital
57
each orbital can hold a maximum of ... electrons
two
58
possible values of ml are the integers between ... and ..., including ..
-l; +l; 0
59
spin quantum number, ms, can be either ... or ...
when two electrons are in the same orbital, they must have opposite spins --> ...
electrons in different orbitals with the same spins are said to have ... spins
+1/2; -1/2;
paired;
parallel
60
...: designate the pattern by which subshells are filled and the number of electrons within each principal energy level and subshell
electron configurations
61
... (... principle): electrons fill from lower- to higher- energy subshells
Aufbau principle; building up
62
... rule can rank subshells by increasing energy --> the lower the energy of the subshell
if two subshells have the same n + 1 value, the subshell with the ... value has a lower energy and will fill with electrons first
N + 1; '
| lower n
63
...: within a given subshell, orbitals are filled such that there is a max number of half-filled orbitals with parallel spins
basis for this preference is ...
Hund's rule;
| electron repulsion
64
... and ... orbitals have lower energies than other states
| exceptions in electron configs: chromium and other elements in its group and copper and other elements in its group
half-filled; fully-filled
65
materials composed of atoms with unpaired electrons will orient their spins in alignment with a ... and the material will be weakly attracted to it ---> ...
magnetic field; paramagnetic
66
materials consisting of atoms that have only paired electrons will be slightly ... by a magnetic field --> ...
repelled; diamagnetic
67
...: the chemical and physical properties of the elements are dependent, in a periodic way, upon their atomic numbers
periodic law
68
elements are arranged into ... (rows) and .../... (columns) based on atomic number
periods; groups/families
69
groups contain elements that have the same ... and share similar chemical properties
electronic configuration in their valence shell
70
the A elements are the ... elements and include groups IA (1A) through VIIIA(8A) --> have valence electrons in the orbitals of either ... or ... subshells
representative;
| s; p;
71
B elements are ... elements and include the transition elements and the lanthanide and actinide series
nonrepresentative
72
metals are lustrous solids that have the qualities of ...and ... (can be pulled/drawn into wires)
malleability; ductility
73
metals have low effective ..., low ..., and low ..., small ..., large ...
```
nuclear charge;
electronegativity;
electron affinity;
ionic radius;
atomic radius
```
74
many transition metals have two or more
oxidation states
75
metals are good conductors because their valence electrons are held ... and are ...
loosely; free to move
76
nonmetals are generally brittle in the solid state and have high ..., .., and ... as well as small ... and large.... They are poor conductors
unable to easily give up electrons
ionization energies; electron affinities; electronegativities;
atomic radii; ionic radii
77
.../...: share some characteristics with both metals and nonmetals
electronegativities and ionziation energies are intermediate
physical properties vary widely
reactivities are dependent on the elements with which they are reacting
metalloids; semimetals
78
as the positivity of the nucleus increases, the electrons surrounding the nucleus experience a stronger electrostatic pull toward the center of the atom --> ... (Zeff)
for elements in the same period, Zeff increases from ... to ...
effective nuclear charge; left; right
79
as one moves down the elements of a given group the ... number increases by one each time --> valence electrons are increasingly separated from the nucleus, leading to a reduction in the ... between valence electrons and the nucleus
principal quantum; electrostatic attraction
80
elements can also gain/lose electrons in order to achieve a stable octet formation representative of the noble (inert) gases --> ...
octet rule
81
atomic radius of an element is equal to ... the distance between the centers of two atoms of an element that are briefly in contact
1/2
82
as we move across a period, the radius ... because the number of inner shell e- remains constant and the ... is increasing
as we move down a group, radii ...
decreases; number of inner shell electrons; increases
83
nonmetals close to the metalloids gain electrons while their nuclei maintain the same charge and thus have a ... ionic radius than their counterparts closer to group 8A
because they lose many more electrons to achieve stability
metals closer to the metalloids show the opposite trend, bc they must ... to achieve stability
larger; gain many more electrons
84
... (...) is the energy required to remove an electron from a gaseous species --> endothermic process
greater Zeff, more tightly bound, and ... E
... from left to right and from bottom to top in a group
ionization energy; ionization potential; higher; increases
85
elements in groups IA and IIA have such low ionization energies that they are called the ... --> do not exist naturally in their neutral forms
active metals
86
... --> energy dissipated upon addition of an electron --> exothermic process
stronger Zeff, ... the energy release
these are reported as ... values even though its exothermic
very high for ... because they only need one electron to achieve a stable configuration
electron affinity; greater; positive; halogens
87
... is a measure of attractive force than an atom will exert on an electron in a chemical bond
electronegativity
88
lower ionization energy, the ... the electronegativity (more susceptible to losing an electron means you don't attract electron as strongly)
exception: ..., have high ionization energies but low electronegativities
pauling electronegativity scale assigns ... to fluorine
electroneg ... across a period and down a group
lower; noble gases;
4.0;
increases
89
... metals (group 1): lowest ... metals, low ..., largest ...
alkali; density; Zeffs; atomic radii
90
alkali metals:
low ..., low ..., low ...
readily react with nonmetals
very reactive
ionization energies;
electron affinities;
electronegativities
91
... metals (group 2): similar to alkali, but have higher ... and slightly smaller ...
also extremely reactive
alkaline earth; Zeffs; atomic radii
92
... (group 16): nonmetals and metalloids that are crucial for biological function --> each have 6 valence electrons
... atomic radii and ... ionic radii
chalcogens;
| small; large
93
chalcogens:
... extremely important, ... is important for amino acids and some vitamins, ... is an important nutrient for microorganisms and has a role in protection from oxidative stress
remainder of the group is generally toxic
at high concs. these elements can be toxic
oxygen; sulfur; selenium
94
... (group 17): highly reactive nonmetals with variable physical properties
range from gaseous to liquid to solid forms
high ... and ...
very reactive and are normally found as ... or ... molecules
halogens;
| electronegativities; electron affinities; ions; diatomic
95
... (group 18): inert gases w/ minimal chemical reactivity
... ionization energies, and for at least the first 3 they have no measurable ...
... boiling points
noble gases;
high; electronegs;
low
96
... (groups 3-12): metals with very low ..., ..., and ...
transition metals; electron affinities; ionization energies; electronegativities
97
transition metals:
have ... melting and boiling points
malleable and good conductors due to loosely held electrons in their ... orbitals
many of them can have different ...
tend to associate in solution either with molecules of water (hydration complexes) or with nonmetals --> variable solubility
high;
d;
oxidation states;
98
a perceived color is that which is ... by the object
if an object absorbs a given color of light and reflects all others, our brain mixes these subtraction frequencies and we perceive the ... color of the absorbed pigment
reflected; complementary
99
... --> some elements are stable with fewer than eight electrons in their valence shell (e.g. hydrogen, helium, lithium, beryllium, boron)
... --> any element in period 3 and greater can hold more than 8 electrons (e.g. phosphorus, sulfur, chlorine, and many more)
incomplete octet; expanded octet;
100
odd number of electrons: any molecule with an odd number of valence electrons cannot distribute those electrons to
give eight to each atom
101
...: one or more electrons from an atom with a low ionization energy are transferred to an atom with a high electron affinity
ionic bonding
102
ionic bonding:
held together by ...
... structures --> to minimize repulsion and maximize attractive forces -- no individual molecular bonds
electrostatic attractions; crystal lattice
103
...: sharing electron pairs, degree of sharing dependent on electronegativities
typically between ...
equal sharing - ...
unequal sharing - ...
...: both of the shared electrons are contributed by only one of the two atoms
```
covalent bonding;
two nonmetals;
nonpolar;
polar;
coordinate covalent
```
104
for ionic bonds to form, electronegativity difference must be above ...
very high ... and ...
tend to dissolve readily in water and polar solvents
good ... in molten/aqueous states
1.7;
melting and boiling points;
conductors of electricity
105
when atoms of similar electronegativities form a compound, it is ... to form an ionic bond
energetically unfavorable
106
polar compounds have relatively ... intermolecular (between molecules) interactions
lower melting and boiling points
do not ...
poor ...
weak;
dissociate into ions;
conductors of electricity
107
...: number of shared electron pairs between two atoms
bond order
108
...: avg distance between the two nuclei of atoms in a bond --> higher bond order = ... bond length
bond length; shorter;
109
...: energy required to break a bond by separating its components into their isolated, gaseous atomic states --> higher bond order = ... bond energy
bond energy; higher
110
...: occurs when two atoms have a relative difference in electronegativities --> atom with higher electronegativity has more of the ...
generally, electronegs lower than ... are considered nonpolar bonds
polarity; electron density; .5
111
dipole moment of a polar bond is a vector quantity given by the equation ..., where p is the dipole moment, q is the magnitude of charge and d is the displacement vector
measured in ... unites (...)
p = qd;
| debye; coulomb-meters
112
for coordinate covalent bonds, generally the lone pair of one atom attacks another atom with an ... to form a bond (as in a lewis acid-base rxn)
unhybridized p orbital
113
...: any compound that will accept a lone pair
| ...: any compound that will donate a pair of electrons to form a covalent bond
lewis acid;
| lewis base
114
...: electrons involved in a covalent bond are in the valence shell (valence electrons)
...: electrons in the valence shell that are not involved in covalent bonding
bonding electrons;
| nonbonding electrons
115
purpose of lewis structures is to keep track of the ...
bonded and nonbonded electron pairs
116
number of valence electrons attributed to a particular atom in the Lewis structure of a molecule is not necessarily the same as the number of valence electrons in the ... --> this difference accounts for the ... of an atom in a Lewis structure
neutral atom; formal charge
117
lewis structures do not represent the .... of a real compound. they show the different possible ways in which atoms may be combined to form different compounds or resonance forms of a single compound
actual/theoretical geometry
118
arrangement that minimizes number and magnitude of ... is the most stable
formal charge
119
drawing lewis structures:
... atom tends to be the central atom
valence electrons of the molecule must be the ... of all the valence electrons present
least electronegative; sum
120
formal charge = ,,,
V is the normal number of electrons in the atom's valence shell
Nnonbonding is the number of nonbonding electrons
Nbonding is the number of bonding electrons
V – Nnonbonding – 1/2*Nbonding
121
formal charge ... the effect of electronegativity differences
oxidation numbers ... the effect of electronegativity differences
the actual distribution of electron density is between the extremes predicted by these two values
underestimates; overestimate
122
...: same arrangement of atoms that differ in the specific placement of the electrons
actual electron distribution is a ... of all the resonance forms
more stable the resonance form, the more it contributes
resonance structures;
| hybrid
123
stability of resonance forms;
... or ... formal charges is preferred
less ... between opposite charges is preferred
negative formal charges on more ... atoms is mores table
small; no
charge separation;
electronegative
124
all elements in or beyond the ... period can be exceptions to the octet rule because they can take on more than 8 electrons in their valence shells --> electrons can be placed into orbitals of the d subshell
third
125
... theory: theory to predict geometrical arrangement of atoms in a compound
valence shell electron pair repulsion (VSEPR)
126
VSEPR theory:
3D arrangement is determined by the ... between bonding and nonbonding electron pairs in the valence shell, which arrange themselves as far apart as possible
repulsions
127
Steps of VSEPR:
draw ...
count total number of ... and ... electron pairs in the valence shell of the central atom
arrange electron pairs around the central atom so that they are as ...
lewis structure;
bonding; nonbonding;
far apart as possible
128
(VSEPR)
regions of e- density: 2
shape: ...
angle: ...
linear; 180
129
(VSEPR)
regions of e- density: 3
shape; ...
angle: ...
trigonal planar;
| 120
130
(VSEPR)
regions of e- density: 4
shape: ...
angle: ...
tetrahedral; 109.5
131
(VSEPR)
regions of e- density: 5
shape: ...
angle: ..., ..., ...
trigonal bipyramidal; 90; 120; 180
132
(VSEPR)
regions of e- density: 6
shape: ...
angle: ..., ....
octahedral; 90; 180
133
electronic geometry describes spatial arrangement of all pairs of electrons, including ...
bonding and lone pairs
134
molecular geometry describes the spatial arrangement of only the ...
bonding pairs of electrons
135
...: number of atoms that surround and are bonded to a central atom
coordination number
136
electronic geometry determines
ideal bond angle
137
presence of bond dipoles does not necessarily mean the entire molecule is ... --> dipoles may cancel one another (as in CO2)
polar
138
when two atoms bond, the atomic orbitals interact to form a ... that describes the probability of finding the bonding electrons in a given space --> obtained by combining the ... of the atomic orbitals
molecular orbital; wave functions
139
overlap of two atom orbitals describes the ...
if signs of two atomic orbitals is the same: ...
if the signs are different: ..
molecular orbital; bonding orbital;
| antibonding orbital
140
... bonding: orbitals overlap head-to-head
| free rotation
sigma
141
... bond: overlap forms two parallel electron cloud densities
no free rotation
pi
142
intermolecular interactions can be overcome with small or moderate amounts of energy and are ... than covalent bonds
weaker
143
(intermolecular interactions)
london dispersion: short lived and rapidly shifting dipoles caused by ... in a nonpolar covalent bond --> weakest of the van der Waals
do not extend over ....
random movement of electrons; long distances
144
(intermolecular interactions) london dispersion:
dependent on how easily a molecule is ... --> how easily its electrons shift around
... molecules are more polarizable (prob bc Zeff isn't as great)
polarized; large
145
(intermolecular interactions) dipole-dipole interactions: ... ends of respective dipoles orient themselves near one another
temporary bonding interaction
present in ... and ... phases but not ... phases, bc in this phase the particles are too ...
oppositely charged; solid; liquid; gas; far apart
146
(intermolecular interactions)
dipole-dipole:
these interactions grant polar species...
different than london dispersion due to ...
higher melting and boiling points; duration
147
(intermolecular interactions) hydrogen bonds: unusually strong form of ... that can be intra or intermolecular
substances that have H bonding tend to have unusually high ... compared to compounds of similar molecular weights that don't have H bonding
important for water, alcohol, amines, and carboxylic acids
dipole-dipole; boiling points
148
compounds: pure substances composed of two or more elements in a ...
fixed proportion
149
...: combination of two or more atoms held together by covalent bonds
molecule
150
molecules are smallest units of compounds that display their ... properties
ionic compounds do not form true molecules: defined by ... instead, which represent the empirical formula of the compound
identifying; formula units;
151
...: sum of the atomic weights of all the atoms in a molecule, amu/molecule
molecular weight
152
formula weight of an ionic compound is the sum of the atomic weights of the constituent ions according to its ..., amu/molecule
empirical formula
153
mole: quantity of any substance equal to the number of particles found in ... --> Avogadro's number (Na) = ...
12 g of C-12; 6.022 x 10^23 1/mol
154
..: mass of one mol of a compound, expressed in g/mol
molar mass
155
...: how many moles of the thing we are interested in will one mole of a given compound produce? (e.g. Na will donate one equivalent of electrons - 1 mole- but magnesium will donate two equivalents of electrons - 2moles)
... measures equivalents in grams
equivalent weight/equivalents; gram equivalent
156
...: measure of concentration given in the units equivalents/L
normality (N)
157
normality calculations always assume that a reaction will
proceed to completion
158
molarity = ..., where n is the number of protons, hydroxide ions, electrons, or ions produced/consumed by the solute
normality/n
159
...: skeletal representations of compounds that show the various bonds between the constituent atoms of a compound
structural formulas
160
...: any pure sample of a given compound will contain the same element in an identical mass ratio
law of constant composition
161
...: simplest whole number ratio of the elements in the compound
... gives the exact number of atoms of each element in the compound and is a multiple of the empirical formula
empirical formula; molecular formula
162
... is the percent of a specific compound that is made up of a given element
percent composition
163
percent comp = ...
| can be calculated using the empirical or molecular formula
mass of element in formula/molar mass *100%
164
... rxn: two or more reactants forming one product
combination
165
... rxn: opposite of combination; single reactant breaks down into two or more products
decomposition
166
... rxns: involves a fuel (usually a ...) and an oxidant (typically ...) and forms CO2 and water
combustion; hydrocarbon; oxygen
167
... rxn: when an atom or ion in a compound is replaced by an atom or ion of another element
also ... rxns
single-displacement; redox
168
.../... rxns: elements from two different compounds swap places with each other to form two new compounds
double-displacement; metathesis
169
double-displacement/metathesis:
occurs when one of the products is removed as a ... or ... when two of the original species combine to form a weak electrolyte that remains undissociated in solution
precipitate; gas
170
... rxns: double-displacement rxns in which acid reacts with a base to produce a salt and usually water as well
neutralization rxn
171
chemical equations must be balanced to reflect the laws of ...
conservation of mass and charge
172
...: numbers placed in front of each compound in a chemical equation, which indicate the relative number of moles of a given species involved in the rxn
stoichiometric coefficients
173
in most reactions, one reagent will be consumed first --> ...
limiting reagent
174
limiting reagent:
limits the amount of ... that can be formed in the rxn
reactants that remain after all the limiting reagent is used up are called ...
it is not the absolute mole quantities fo the reactants that determine which is the limiting reagent. rather, the rate at which ... combined with the absolute mole quantities determines which rate is the limiting reagent
product;
excess reagents;
reactants are consumed
175
...: amount of product predicted or actually obtained when a rxn is carried out
yield of a rxn
176
...: max product that can be generated as predicted from the chemical equation, assuming that all of the limiting reagent has been consumed, no side products have formed, and all of the product was collected
...: amount of product actually obtained
...: actual/theoretical *100%
theoretical yield;
actual yield;
percent yield
177
for stoichiometry rxns, the goal with ions is to identify
oxidation states
178
for elements that can form more than one positive ion, the charge is indicated by a roman numeral in parentheses following the name of the element
a less common method is to add the endings ... or ... to represent the ions with lesser and greater charge, respectively
-ous; -ic
179
monatomic anions have the ending
-ide
180
polyatomic anions that contain oxygen are ... when an element forms two oxyanions, the one with less oxygen ends in ... and the one with more oxygen ends in ...
oxyanions; -ite; -ate
181
in extended series of oxyanions, ... and ... are used to indicate even less oxygen and even more oxygen, respectively
hypo-; per-
182
polyatomic anions often gain one or more ... to form anions of lower charge. the resulting ions are named by adding the word ... or ... to the front of the anion's name. older methods use the prefix ... to indicate presence of a single hydrogen ion
H+ ions; hydrogen; dihydrogen; bi-
183
some elements can have several different charges depending on other atoms in the compound: ...
oxidation states
184
...: solutes that enable solutions to carry currents --> ... is governed by the presence and concentration of ions in solution
electrolytes; conductiviity
185
tendency of ionic solute to solvate (dissolve) in water can be high/low
... dissociate completely into its constituent ions --> can include molecular compounds with highly ... bonds that dissociate into ions when dissolved (e.g. HCl)
... dissociate incompletely
strong electrolytes; polar covalent; weak electrolytes
186
gibbs free energy helps determine if a reaction will
run spontaneously
187
the overall chemical rxn rarely shows all the steps of that rxn, which is elucidated in the
rxn mechansim
188
knowing the mechanism can explain the rxn's ..., ..., and ...
rate; thermodynamics; position of equilibrium
189
the slowest step in any proposed mechanism is the ...step: the overall rxn cannot proceed any faster than that slowest step
rate-determining
190
...: rate of a rxn is proportional to the number of collisions per second
not all collisions result in a ...
collision theory of chemical kinetics;
| chemical rxn
191
effective collisions must have the correct ... and enough ... --> minimum energy of collision that is necessary is the ... or the ...
orientation; energy; activation energy; energy barrier
192
(rxn rates) rate = ...
| Z = total number of ... occurring per second and f is the fraction of ...
Z*f;
| collisions; effective collisions
193
(rxn rates) arrhenius equation: ...
k is the rate constant, a is the frequency factor, Ea is the activation energy, R is the ideal gas constant, T is the temp in kelvins
k=Ae^((-Ea)/RT)
194
(rxn rates) arrhenius equation contd:
| .../... ==> measure of how often molecules in a certain reaction collide (units of 1/s)
frequency factor; attempt frequency
195
(rxn rates) frequency factor can be increased by increasing the amount of ... present --> more molecules = greater ...
molecules; chance of collision
196
(rxn rates) ...: occurs when molecules collide with sufficient energy and their old bonds weaken and the new bonds begin to form
aka ...
transition state; activate dcomplex
197
(rxn rates) transition state:
... energy than both the reactants and the products
energy required to reach this point is the ... energy
can either dissociate into the products or revert back to reactants
these are not ... ---> do not have distinct identities and are very transient
greater; activation;
| intermediates
198
...: difference between the free energy of the products and the free energy of the reactants
negative free energy change --> ...
positive free energy change --> ...
free energy change of the rxn;
exergonic;
endergonic
199
difference in free energy between .... and the .. is the activation energy of the forward rxn; difference in free energy between the ... and the ... is the activation energy of the reverse rxn
TS; reactants; TS; products
200
(factors that influence rxn rate) greater ... of reactants --> greater rate of ...
increasing ....
rate will increase for all but ... rxns
... of gaseous molecules will act as a measure of concentration
concs; effective collisions;
frequency factor;
zero-order;
partial pressures
201
(factors that influence rxn rate)
rxn rate increases with ... bc higher values of this means higher ... of particles
more particles will have enough energy to surpass activation energy
temperature; kinetic energy
202
(factors that influence rxn rate) there is an ... temp for activity
generally (NOT always) for biological systems, raising the temp by 10 degrees C will result in an approximate ... of the rxn rate
optimal; doubling
203
(factors that influence rxn rate) the ... in which a rxn takes place can have an effect --> polarity, physical state, etc.
generally, ... solvents are preferred bc their molecular dipole tends to polarize the bonds of the reactants, lengthening and weakening them, which allows the rxn to occur faster
medium; polar
204
(factors that influence rxn rate) catalysts increase reaction rate by decreasing ...
activation energy
205
(factors that influence rxn rate) enzymes can increase ... of collisions, change ... of the reactants, donate ... to the reactants, or reduce ... within reactant molecules
frequency; orientations; electron density; intramolecular bonding
206
(factors that influence rxn rate) ...: catalyst is in the same phase (solid, liquid, gas) as the reactants
...: catalyst is in a distinct phase
homogenous catalysis; heterogenous catalysis
207
(factors that influence rxn rate) catalysts:
change the forward and reverse rxn rates by the same factor
do not affect ...
cannot make a nonspontaneous rxn ...
equilibrium position; spontaneous
208
rxn rates are expressed in units of ...
moles/L*s or M/s (molarity/s)
209
On the MCAT, the values of x and y in the rate equation rate=k〖[A]〗^x 〖[B]〗^y , x and y are almost never the same as the ...
this only occur when the reaction mechanism is a ... and the balanced overall rxn is reflective of the entire chemical process and when the complete rxn mechanism is given and the ... is indicated
the values of k, x, and y must be determined experimentally
stoichiometric coefficients; single step; rate-determining step
210
...: equilibrium constant expression
law of amss action
211
expression for chemical kinetics- the rate law expression- only includes reactants whereas Keq might have
products included
212
for a reversible reaction, Keq is equal to the ratio of the rate constant for the ... divided by that of the ...
forward rxn; reverse rxn
213
... rxn: rate of formation of the product is independent of changes in concentrations of any of the reactants
Rate = ...
zero-order rxn; k
214
zero-order rxn:
for these, rates can only be changed by changing the ... or adding a ...
on a conc vs time curve, this will show as a ... graph --> slope of this line is the opposite of the ...
temperature; catalyst; linear; rate constant
215
... rxn: a rate that is directly proportional to only one reactant
rate = ... or rate = ...
... is an example of this
first-order; k[A]; k[B];
| radioactive decay
216
first order rxn:
| conc of radioactive substance A at any time t can be expressed as:
[A]t = [A]0*e^-kt
217
first-order rxn:
a first order rate law implies that the rxn begins when the molecule undergoes a chemical change by itself, without a ..., and usually without a ... with another molecule (e.g. SN1 rxn)
conc vs. time curve shows a ... graph, but ... would reveal a straight line whose slope would be the opposite of the ...
chemical interaction; physical interaction; nonlinear; ln[A] vs time; rate constant k
218
... rxn has a rate that is proportional to either the concs of two reactants or to the square of the conc of a single reactant
second order
219
(second order rxn) rate = ... or rate = ... or rate = ...
| often suggests a physical collision between ...
k[A][B]; k[A]^2; k[B]^2;
| two reactant molecules
220
(second order rxn) plotting a second order rxn with respect to a single reactant on a conc vs. time curve shows a ... graph --> rate of formation of product is dependent on the ...
... graph will be linear with a slope equal to the ...
nonlinear; conc of reactant;
| 1/[A] vs. time; rate constant
221
there are few processes with a ... process --> it's much harder and rarer for three particles to collide at the same time with enough energy and the correct orientation
termolecular
222
... rxns: non-integer orders or rxns with rate orders that vary over the course of the rxn
mixed-order
223
mixed-order rxns:
fraction mixed-order rxns are also called ...
mixed order primarily refers to those rxns whose rates ...
broken-order; vary over time
224
mixed-order rxns:
ex. rate = ...
this would be for the equation aA + bB --> cC + dD
k1[C][A]^2 /k2 + k3[A]
225
mixed-order rxns:
For large values of [A] at the beginning of the reaction, k3[A] >> k2, so the reaction will seem to be ...
At the end of the rxn, when [A] is low, k2 >> k3, making the reaction appear ...
first order with respect to A ;
| second-order with respect to A
226
... and ... refer to enthalpy, not gibbs free energy
endothermic; exothermic
227
...: rxn proceeds in one direction only, goes to completion, and the max amount of product formed is determined by the amount of limiting reagent initially present
irreversible rxns
228
... : rxns can proceed in the forward/reverse direction; usually do not go to completion because the products can react together to reform the reactants
reversible rxns
229
reversible rxns:
when the system is closed and no products/reactants are added/removed, the system will eventually settle into a state in which the rate of the forward and reverse rxns are .. and the concs of product and reactant are ...
equal; constant
230
reversible rxns:
... equilibrium --> forward and reverse rxns are still occurring
... equilibrium --> the rxns have stopped
dynamic;
| static
231
...: measure of the distribution of energy throughout a system or between a system and its enviro
entropy
232
entropy:
for a reversible rxn at a given temp, the rxn will reach equilibrium when the system's ... is at a max and the ... of the system is at a min--> most favorable energetic conditions
entropy or energy distribution; Gibbs free energy
233
For aA + bB ⇌ cC + dD, the law of mass action states that, if it is at equilibrium at a constant temp, then the following ratio is constant:
Keq = [C]^c[D]^d / [A]^a[B]^b
234
when Ratef = Rater, the system is in ... and the rate expressions for the forward and reverse rxns can be ... the resulting value of kf/kr is a constant and is the ...
equilibrium; set equal to each other; equilibrium constant Kc
235
subscript c of the equilibrium constant Kc indicates that it's in terms of ... and that Kc is interchangeable with ...
... is used for gases, with the subscript indicating that its in terms of ...
concentration; Keq; Kp; pressure
236
while forward and reverse reaction rates are equal at equilibrium, the ... of the reactants and products are not usually equal, meaning that the .... are not usually equal to each other --> Kc = ...
concentrations; forward and reverse reaction rate constants; kf/kr
237
when a rxn is multistep, the equilibrium constant for the overall rxn is found by ...
yields equilibrium constant equal to the .../..., each raised to their ...
multiplying together the equilibrium constants for each step of the rxn;
concs of products/ concs of reactants; stoichiometric coefficients
238
equilibrium is a state that is only achieved through ... --> ... Qc can be compared to Kc to see if rxn has reached equilibrium yet
Qc = ...
time; reaction quotient;
| [C]^c[D]^d / [A]^a[B]^b
239
Qc:
| concs of the reactants and products are not ... when the Q value is being calculated
constant
240
When Q < Keq, the forward rxn is ... --> ... than at equilibrium
not at equilibrium; higher reactant conc
241
When Q = Keq, the rxn is at ...
reactants and products are present in ...
... and ... are equal
dynamic equilibrium;
equilibrium proportions;
forward and reverse rates
242
when Q > Keq, the forward rxn has ...
... than at equilibrium
... is increased to restore equilibrium
exceeded equilibrium;
greater product conc
reverse rxn
243
concs of ... and ... do not appear in the equilibrium constant expression bc this expression is technically based on the ... of compound, not concs --> activities of these types of compounds that are excluded is ...
pure solids and liquids; activities; 1
244
Keq is characteristic of a specific rxn at a specific ... --> ...
temperature; temp-dependent
245
if the equilibrium constant for a rxn in one direction is Keq, the equilibrium rxn for the reverse rxn is ...
1/Keq
246
A Keq of 1 can be a valuable reference pt, given that Keq = [products]/[reactants] --> can help us determine if [] of reactants is ... or ...
greater or less than that of the products at equilibrium
247
if conc of products is greater than conc of reactants, Keq will be
greater than 1
248
sign and scale of exponents for rate function can give more info about relative quantities:
a rxn that strongly favors products will have a ..., ... exponent and the larger the exponent, the ... reactant will be present at equilibrium --> rxn almost ...
large; positive; less; goes to completion
249
sign and scale of exponents for rate function can give more info about relative quantities:
... exponent indicates a rxn that strongly favors reactants at equilibrium--> only small amount of reactant converted to product
this can be convenient in assuming that amount reacted can be considered negligible compared to what remains!
o If the value for Keq is within one or two orders of magnitude of... or if the conc of reactant that goes to product is within two orders of the magnitude of the ... this estimation is not valid
large negative; one; initial conc of reactant
250
...: if a stress is applied to a system, the system shifts to relieve that applied stress
Le Chatelier's principle
251
Le Chat's principle:
| if reactants are added to a system at equilibrium, ... and the rxn will proceed in the ... direction
Qc < Keq; forward
252
Le Chat's principle:
if reactants are removed from a system at equilibrium, or products are added, ... and the rxn will proceed in the ... direction
Qc > Keq; reverse
253
when a system is compressed, its volume ... and its total pressure ...
decreases; increases
254
increase in total pressure of a compressed system results in an increase in the ... of each gas in the system, and the system is no longer in equilibrium. the system will then move in the forward/reverse direction, towards whichever side has the ... of gas
partial pressures; total number of moles (check in txt if this is right)
255
when one expands the volume of a system, the total and partial pressures ... and the system is no longer in equilibrium. it will react in the direction of the side with the ... of gas to restore the pressure
decrease; greater number of moles
256
changing the temperature of a system, unlike the above changes, does not change the ..., but rather changes the ...
Qc; Keq
257
changing temps does not cause the concs or partial pressures of the reactants and products to change immediately, so Q immediately after the temp change is the same as before, but now Q no longer equals Keq
system moves in whatever direction will allow it to reach its new equilibrium state
direction determined by the ... of the rxn
if the rxn is endothermic, heat functions as a ...
if the rxn is exothermic, heat functions as a ...
enthalpy; reactant; product
258
kinetic vs. thermodynamic control -->
... products often form faster and are sometimes called "Fast" products
.. products are associated with greater stability and with a more ... delta G than kinetic products
kinetic; thermodynamic; negative
