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MCAT > Kaplan Gen Chem > Flashcards

Kaplan Gen Chem Flashcards

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1
Q

each proton has an amount of charge equal to the fundamental unit of charge (e = …)

A

1.6 * 10^-19

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2
Q

protons have a mass of about

A

one atomic mass unit

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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

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4
Q

neutrons are …, with a mass only slightly higher than that of the proton

A

neutral

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5
Q

protons and neutrons together make up the majority of an atom’s …

A

mass

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6
Q

… (…): sum of the protons and neutrons in the atom’s nucleus

A

mass number; A

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7
Q

… have the same atomic number but different mass numbers

A

isotopes

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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

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9
Q

mass of an 3- is about … that of a proton

A

1/2000

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10
Q

… force of attraction between protons and electrons are much greater than the … force of attraction between them

A

electrostatic; gravitational

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11
Q

electrons closer to the nucleus are at … energy levels, while those that are in higher electron shells have … energy

A

lower; higher

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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

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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

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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

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15
Q

weighted average of different isotopes is referred to as the

A

atomic weight

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16
Q

because half-life corresponds with …, it helps determine the relative proportions of different isotopes

A

stability

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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

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18
Q

one mole is a number of things equal to avogadro’s number, NA= …

A

6.02 *10^23

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19
Q

Max Planck developed quantum theory, proposing that energy emitted as electromagnetic radiation from matter comes in discrete bundles called …

A

quanta

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20
Q

energy of a quantum is given by the planck relation: E = …
h = …

A

hf;

6.626 * 10^has -34 J*s

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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

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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

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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

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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

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25
Q

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

A

discrete

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26
Q

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 …)

A

getting larger; less negative

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27
Q

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

A

negative sign

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28
Q

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

A

lowest; excited

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29
Q

electrons are not restricted to specific pathways, but tend to be …

A

localized in certain regions of space

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30
Q

at room temp most atoms are

A

in their ground state

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31
Q

when excited electrons return to ground state, they emit discrete amounts of energy in the form of

A

photons

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32
Q 
as electrons go from a lower energy level to a higher energy level, they get AHED: 
.... 
.... 
... 
... (from the nucleus)
A

absorb light;
higher potential
excited
distant

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33
Q

electromagnetic energy of photons can be determined by the following equation: …

A

E = hc/lambda

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34
Q

c is the speed of light in a vacuum –> …

A

3.00 * 10^8 m/s

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35
Q

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

A

atomic emission spectrum

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36
Q

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

A

Lyman;
Balmer;
Paschen

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37
Q

balmer series includes 4 wavelengths in the

A

visible region

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38
Q

Lyman has … energy transitions than balmer and thus has … photon wavelengths in the UV region

A

larger; shorter

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39
Q

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 )]

A

hc/λ= -Rh [1/(ni^2 )-1/(nf^2 )]

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40
Q

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 …

A

higher energy initial state; lower energy final state

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41
Q

every element possess a characteristic … –> wavelengths of absorption correspond to wavelengths of … because the difference in energy between levels remains unchanged

A

absorption spectrum; emission

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42
Q

bohr’s model was inadequate bc it didn’t take into account the … between multiple … surrounding the nucleus

A

repulsion; electrons

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43
Q

electrons move rapidly and are localized within regions of space around the nucleus called …

A

orbitals

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44
Q

Heisenberg uncertainty principle: it is impossible to simultaneously determine, with perfect accuracy, the … and … of an electron

A

momentum; position

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45
Q

four quantum numbers: …, …, …, and …

A

n; l; ml; ms

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46
Q

…: no two electrons in a given atom can possess the same set of four quantum numbers

A

Pauli exclusion principle

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47
Q

the position and energy of an electron described by its quantum numbers are its

A

energy state

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48
Q

value of n limits values of … which limit the values of …

A

l; ml

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49
Q

values of the quantum numbers describe info about the .., …, and … of e- orbitals

A

size; shape; orientation

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50
Q

principal quantum number, n, indicates the … and … of the electron’s shell

A

energy level; radius

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51
Q

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

A

2n^2;

decreases

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52
Q

second quantum number is the … (…) quantum number, designated by l
refers to the … and … of subshells within a given principal energy level

A

azimuthal; angular momentum;

shape; number

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53
Q

angular momentum quantum number:

the n-value tells you the number of … –>the range of possible values for l is … to …

A

possible subshells; 0; n-1

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54
Q

… refers to the shorthand representation of the principal and azimuthal quantum numbers

A

spectroscopic notation

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55
Q

the capacity to hold electrons within each subshell is: …

A

4l + 2

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56
Q

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

A

orbital

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57
Q

each orbital can hold a maximum of … electrons

A

two

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58
Q

possible values of ml are the integers between … and …, including ..

A

-l; +l; 0

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59
Q

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

A

+1/2; -1/2;
paired;
parallel

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60
Q

…: designate the pattern by which subshells are filled and the number of electrons within each principal energy level and subshell

A

electron configurations

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61
Q

… (… principle): electrons fill from lower- to higher- energy subshells

A

Aufbau principle; building up

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62
Q

… 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

A

N + 1; ‘

lower n

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63
Q

…: 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 …

A

Hund’s rule;

electron repulsion

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64
Q

… 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

A

half-filled; fully-filled

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65
Q

materials composed of atoms with unpaired electrons will orient their spins in alignment with a … and the material will be weakly attracted to it —> …

A

magnetic field; paramagnetic

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66
Q

materials consisting of atoms that have only paired electrons will be slightly … by a magnetic field –> …

A

repelled; diamagnetic

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67
Q

…: the chemical and physical properties of the elements are dependent, in a periodic way, upon their atomic numbers

A

periodic law

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68
Q

elements are arranged into … (rows) and …/… (columns) based on atomic number

A

periods; groups/families

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69
Q

groups contain elements that have the same … and share similar chemical properties

A

electronic configuration in their valence shell

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70
Q

the A elements are the … elements and include groups IA (1A) through VIIIA(8A) –> have valence electrons in the orbitals of either … or … subshells

A

representative;

s; p;

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71
Q

B elements are … elements and include the transition elements and the lanthanide and actinide series

A

nonrepresentative

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72
Q

metals are lustrous solids that have the qualities of …and … (can be pulled/drawn into wires)

A

malleability; ductility

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73
Q

metals have low effective …, low …, and low …, small …, large …

A 
nuclear charge; 
electronegativity; 
electron affinity; 
ionic radius; 
atomic radius
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74
Q

many transition metals have two or more

A

oxidation states

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75
Q

metals are good conductors because their valence electrons are held … and are …

A

loosely; free to move

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76
Q

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

A

ionization energies; electron affinities; electronegativities;
atomic radii; ionic radii

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77
Q

…/…: 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

A

metalloids; semimetals

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78
Q

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 …

A

effective nuclear charge; left; right

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79
Q

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

A

principal quantum; electrostatic attraction

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80
Q

elements can also gain/lose electrons in order to achieve a stable octet formation representative of the noble (inert) gases –> …

A

octet rule

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81
Q

atomic radius of an element is equal to … the distance between the centers of two atoms of an element that are briefly in contact

A

1/2

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82
Q

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 …

A

decreases; number of inner shell electrons; increases

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83
Q

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

A

larger; gain many more electrons

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84
Q

… (…) 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

A

ionization energy; ionization potential; higher; increases

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85
Q

elements in groups IA and IIA have such low ionization energies that they are called the … –> do not exist naturally in their neutral forms

A

active metals

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86
Q

… –> 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

A

electron affinity; greater; positive; halogens

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87
Q

… is a measure of attractive force than an atom will exert on an electron in a chemical bond

A

electronegativity

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88
Q

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

A

lower; noble gases;
4.0;
increases

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89
Q

… metals (group 1): lowest … metals, low …, largest …

A

alkali; density; Zeffs; atomic radii

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90
Q

alkali metals:
low …, low …, low …
readily react with nonmetals
very reactive

A

ionization energies;
electron affinities;
electronegativities

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91
Q

… metals (group 2): similar to alkali, but have higher … and slightly smaller …
also extremely reactive

A

alkaline earth; Zeffs; atomic radii

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92
Q

… (group 16): nonmetals and metalloids that are crucial for biological function –> each have 6 valence electrons
… atomic radii and … ionic radii

A

chalcogens;

small; large

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93
Q

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

A

oxygen; sulfur; selenium

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94
Q

… (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

A

halogens;

electronegativities; electron affinities; ions; diatomic

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95
Q

… (group 18): inert gases w/ minimal chemical reactivity
… ionization energies, and for at least the first 3 they have no measurable …
… boiling points

A

noble gases;
high; electronegs;
low

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96
Q

… (groups 3-12): metals with very low …, …, and …

A

transition metals; electron affinities; ionization energies; electronegativities

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97
Q

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

A

high;
d;
oxidation states;

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98
Q

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

A

reflected; complementary

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99
Q

… –> 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)

A

incomplete octet; expanded octet;

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100
Q

odd number of electrons: any molecule with an odd number of valence electrons cannot distribute those electrons to

A

give eight to each atom

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101
Q

…: one or more electrons from an atom with a low ionization energy are transferred to an atom with a high electron affinity

A

ionic bonding

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102
Q

ionic bonding:
held together by …
… structures –> to minimize repulsion and maximize attractive forces – no individual molecular bonds

A

electrostatic attractions; crystal lattice

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103
Q

…: 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

A 
covalent bonding; 
two nonmetals; 
nonpolar; 
polar; 
coordinate covalent
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104
Q

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

A

1.7;
melting and boiling points;
conductors of electricity

105
Q

when atoms of similar electronegativities form a compound, it is … to form an ionic bond

A

energetically unfavorable

106
Q

polar compounds have relatively … intermolecular (between molecules) interactions
lower melting and boiling points
do not …
poor …

A

weak;
dissociate into ions;
conductors of electricity

107
Q

…: number of shared electron pairs between two atoms

A

bond order

108
Q

…: avg distance between the two nuclei of atoms in a bond –> higher bond order = … bond length

A

bond length; shorter;

109
Q

…: energy required to break a bond by separating its components into their isolated, gaseous atomic states –> higher bond order = … bond energy

A

bond energy; higher

110
Q

…: 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

A

polarity; electron density; .5

111
Q

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 (…)

A

p = qd;

debye; coulomb-meters

112
Q

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)

A

unhybridized p orbital

113
Q

…: any compound that will accept a lone pair

…: any compound that will donate a pair of electrons to form a covalent bond

A

lewis acid;

lewis base

114
Q

…: 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

A

bonding electrons;

nonbonding electrons

115
Q

purpose of lewis structures is to keep track of the …

A

bonded and nonbonded electron pairs

116
Q

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

A

neutral atom; formal charge

117
Q

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

A

actual/theoretical geometry

118
Q

arrangement that minimizes number and magnitude of … is the most stable

A

formal charge

119
Q

drawing lewis structures:
… atom tends to be the central atom
valence electrons of the molecule must be the … of all the valence electrons present

A

least electronegative; sum

120
Q

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

A

V – Nnonbonding – 1/2*Nbonding

121
Q

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

A

underestimates; overestimate

122
Q

…: 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

A

resonance structures;

hybrid

123
Q

stability of resonance forms;
… or … formal charges is preferred
less … between opposite charges is preferred
negative formal charges on more … atoms is mores table

A

small; no
charge separation;
electronegative

124
Q

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

A

third

125
Q

… theory: theory to predict geometrical arrangement of atoms in a compound

A

valence shell electron pair repulsion (VSEPR)

126
Q

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

A

repulsions

127
Q

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 …

A

lewis structure;
bonding; nonbonding;
far apart as possible

128
Q

(VSEPR)
regions of e- density: 2
shape: …
angle: …

A

linear; 180

129
Q

(VSEPR)
regions of e- density: 3
shape; …
angle: …

A

trigonal planar;

120

130
Q

(VSEPR)
regions of e- density: 4
shape: …
angle: …

A

tetrahedral; 109.5

131
Q

(VSEPR)
regions of e- density: 5
shape: …
angle: …, …, …

A

trigonal bipyramidal; 90; 120; 180

132
Q

(VSEPR)
regions of e- density: 6
shape: …
angle: …, ….

A

octahedral; 90; 180

133
Q

electronic geometry describes spatial arrangement of all pairs of electrons, including …

A

bonding and lone pairs

134
Q

molecular geometry describes the spatial arrangement of only the …

A

bonding pairs of electrons

135
Q

…: number of atoms that surround and are bonded to a central atom

A

coordination number

136
Q

electronic geometry determines

A

ideal bond angle

137
Q

presence of bond dipoles does not necessarily mean the entire molecule is … –> dipoles may cancel one another (as in CO2)

A

polar

138
Q

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

A

molecular orbital; wave functions

139
Q

overlap of two atom orbitals describes the …
if signs of two atomic orbitals is the same: …
if the signs are different: ..

A

molecular orbital; bonding orbital;

antibonding orbital

140
Q

… bonding: orbitals overlap head-to-head

free rotation

A

sigma

141
Q

… bond: overlap forms two parallel electron cloud densities
no free rotation

A

pi

142
Q

intermolecular interactions can be overcome with small or moderate amounts of energy and are … than covalent bonds

A

weaker

143
Q

(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 ….

A

random movement of electrons; long distances

144
Q

(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)

A

polarized; large

145
Q

(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 …

A

oppositely charged; solid; liquid; gas; far apart

146
Q

(intermolecular interactions)
dipole-dipole:
these interactions grant polar species…
different than london dispersion due to …

A

higher melting and boiling points; duration

147
Q

(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

A

dipole-dipole; boiling points

148
Q

compounds: pure substances composed of two or more elements in a …

A

fixed proportion

149
Q

…: combination of two or more atoms held together by covalent bonds

A

molecule

150
Q

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

A

identifying; formula units;

151
Q

…: sum of the atomic weights of all the atoms in a molecule, amu/molecule

A

molecular weight

152
Q

formula weight of an ionic compound is the sum of the atomic weights of the constituent ions according to its …, amu/molecule

A

empirical formula

153
Q

mole: quantity of any substance equal to the number of particles found in … –> Avogadro’s number (Na) = …

A

12 g of C-12; 6.022 x 10^23 1/mol

154
Q

..: mass of one mol of a compound, expressed in g/mol

A

molar mass

155
Q

…: 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

A

equivalent weight/equivalents; gram equivalent

156
Q

…: measure of concentration given in the units equivalents/L

A

normality (N)

157
Q

normality calculations always assume that a reaction will

A

proceed to completion

158
Q

molarity = …, where n is the number of protons, hydroxide ions, electrons, or ions produced/consumed by the solute

A

normality/n

159
Q

…: skeletal representations of compounds that show the various bonds between the constituent atoms of a compound

A

structural formulas

160
Q

…: any pure sample of a given compound will contain the same element in an identical mass ratio

A

law of constant composition

161
Q

…: 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

A

empirical formula; molecular formula

162
Q

… is the percent of a specific compound that is made up of a given element

A

percent composition

163
Q

percent comp = …

can be calculated using the empirical or molecular formula

A

mass of element in formula/molar mass *100%

164
Q

… rxn: two or more reactants forming one product

A

combination

165
Q

… rxn: opposite of combination; single reactant breaks down into two or more products

A

decomposition

166
Q

… rxns: involves a fuel (usually a …) and an oxidant (typically …) and forms CO2 and water

A

combustion; hydrocarbon; oxygen

167
Q

… rxn: when an atom or ion in a compound is replaced by an atom or ion of another element
also … rxns

A

single-displacement; redox

168
Q

…/… rxns: elements from two different compounds swap places with each other to form two new compounds

A

double-displacement; metathesis

169
Q

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

A

precipitate; gas

170
Q

… rxns: double-displacement rxns in which acid reacts with a base to produce a salt and usually water as well

A

neutralization rxn

171
Q

chemical equations must be balanced to reflect the laws of …

A

conservation of mass and charge

172
Q

…: 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

A

stoichiometric coefficients

173
Q

in most reactions, one reagent will be consumed first –> …

A

limiting reagent

174
Q

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

A

product;
excess reagents;
reactants are consumed

175
Q

…: amount of product predicted or actually obtained when a rxn is carried out

A

yield of a rxn

176
Q

…: 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%

A

theoretical yield;
actual yield;
percent yield

177
Q

for stoichiometry rxns, the goal with ions is to identify

A

oxidation states

178
Q

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

A

-ous; -ic

179
Q

monatomic anions have the ending

A

-ide

180
Q

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 …

A

oxyanions; -ite; -ate

181
Q

in extended series of oxyanions, … and … are used to indicate even less oxygen and even more oxygen, respectively

A

hypo-; per-

182
Q

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

A

H+ ions; hydrogen; dihydrogen; bi-

183
Q

some elements can have several different charges depending on other atoms in the compound: …

A

oxidation states

184
Q

…: solutes that enable solutions to carry currents –> … is governed by the presence and concentration of ions in solution

A

electrolytes; conductiviity

185
Q

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

A

strong electrolytes; polar covalent; weak electrolytes

186
Q

gibbs free energy helps determine if a reaction will

A

run spontaneously

187
Q

the overall chemical rxn rarely shows all the steps of that rxn, which is elucidated in the

A

rxn mechansim

188
Q

knowing the mechanism can explain the rxn’s …, …, and …

A

rate; thermodynamics; position of equilibrium

189
Q

the slowest step in any proposed mechanism is the …step: the overall rxn cannot proceed any faster than that slowest step

A

rate-determining

190
Q

…: rate of a rxn is proportional to the number of collisions per second
not all collisions result in a …

A

collision theory of chemical kinetics;

chemical rxn

191
Q

effective collisions must have the correct … and enough … –> minimum energy of collision that is necessary is the … or the …

A

orientation; energy; activation energy; energy barrier

192
Q

(rxn rates) rate = …

Z = total number of … occurring per second and f is the fraction of …

A

Z*f;

collisions; effective collisions

193
Q

(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

A

k=Ae^((-Ea)/RT)

194
Q

(rxn rates) arrhenius equation contd:

…/… ==> measure of how often molecules in a certain reaction collide (units of 1/s)

A

frequency factor; attempt frequency

195
Q

(rxn rates) frequency factor can be increased by increasing the amount of … present –> more molecules = greater …

A

molecules; chance of collision

196
Q

(rxn rates) …: occurs when molecules collide with sufficient energy and their old bonds weaken and the new bonds begin to form
aka …

A

transition state; activate dcomplex

197
Q

(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

A

greater; activation;

intermediates

198
Q

…: difference between the free energy of the products and the free energy of the reactants
negative free energy change –> …
positive free energy change –> …

A

free energy change of the rxn;
exergonic;
endergonic

199
Q

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

A

TS; reactants; TS; products

200
Q

(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

A

concs; effective collisions;
frequency factor;
zero-order;
partial pressures

201
Q

(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

A

temperature; kinetic energy

202
Q

(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

A

optimal; doubling

203
Q

(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

A

medium; polar

204
Q

(factors that influence rxn rate) catalysts increase reaction rate by decreasing …

A

activation energy

205
Q

(factors that influence rxn rate) enzymes can increase … of collisions, change … of the reactants, donate … to the reactants, or reduce … within reactant molecules

A

frequency; orientations; electron density; intramolecular bonding

206
Q

(factors that influence rxn rate) …: catalyst is in the same phase (solid, liquid, gas) as the reactants
…: catalyst is in a distinct phase

A

homogenous catalysis; heterogenous catalysis

207
Q

(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 …

A

equilibrium position; spontaneous

208
Q

rxn rates are expressed in units of …

A

moles/L*s or M/s (molarity/s)

209
Q

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

A

stoichiometric coefficients; single step; rate-determining step

210
Q

…: equilibrium constant expression

A

law of amss action

211
Q

expression for chemical kinetics- the rate law expression- only includes reactants whereas Keq might have

A

products included

212
Q

for a reversible reaction, Keq is equal to the ratio of the rate constant for the … divided by that of the …

A

forward rxn; reverse rxn

213
Q

… rxn: rate of formation of the product is independent of changes in concentrations of any of the reactants
Rate = …

A

zero-order rxn; k

214
Q

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 …

A

temperature; catalyst; linear; rate constant

215
Q

… rxn: a rate that is directly proportional to only one reactant
rate = … or rate = …
… is an example of this

A

first-order; k[A]; k[B];

radioactive decay

216
Q

first order rxn:

conc of radioactive substance A at any time t can be expressed as:

A

[A]t = [A]0*e^-kt

217
Q

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 …

A

chemical interaction; physical interaction; nonlinear; ln[A] vs time; rate constant k

218
Q

… 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

A

second order

219
Q

(second order rxn) rate = … or rate = … or rate = …

often suggests a physical collision between …

A

k[A][B]; k[A]^2; k[B]^2;

two reactant molecules

220
Q

(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 …

A

nonlinear; conc of reactant;

1/[A] vs. time; rate constant

221
Q

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

A

termolecular

222
Q

… rxns: non-integer orders or rxns with rate orders that vary over the course of the rxn

A

mixed-order

223
Q

mixed-order rxns:
fraction mixed-order rxns are also called …
mixed order primarily refers to those rxns whose rates …

A

broken-order; vary over time

224
Q

mixed-order rxns:
ex. rate = …
this would be for the equation aA + bB –> cC + dD

A

k1[C][A]^2 /k2 + k3[A]

225
Q

mixed-order rxns:
 For large values of [A] at the beginning of the reaction, k3[A]&raquo_space; k2, so the reaction will seem to be …
 At the end of the rxn, when [A] is low, k2&raquo_space; k3, making the reaction appear …

A

first order with respect to A ;

second-order with respect to A

226
Q

… and … refer to enthalpy, not gibbs free energy

A

endothermic; exothermic

227
Q

…: 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

A

irreversible rxns

228
Q

… : rxns can proceed in the forward/reverse direction; usually do not go to completion because the products can react together to reform the reactants

A

reversible rxns

229
Q

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 …

A

equal; constant

230
Q

reversible rxns:
… equilibrium –> forward and reverse rxns are still occurring
… equilibrium –> the rxns have stopped

A

dynamic;

static

231
Q

…: measure of the distribution of energy throughout a system or between a system and its enviro

A

entropy

232
Q

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

A

entropy or energy distribution; Gibbs free energy

233
Q

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:

A

Keq = [C]^c[D]^d / [A]^a[B]^b

234
Q

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 …

A

equilibrium; set equal to each other; equilibrium constant Kc

235
Q

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 …

A

concentration; Keq; Kp; pressure

236
Q

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 = …

A

concentrations; forward and reverse reaction rate constants; kf/kr

237
Q

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 …

A

multiplying together the equilibrium constants for each step of the rxn;
concs of products/ concs of reactants; stoichiometric coefficients

238
Q

equilibrium is a state that is only achieved through … –> … Qc can be compared to Kc to see if rxn has reached equilibrium yet
Qc = …

A

time; reaction quotient;

[C]^c[D]^d / [A]^a[B]^b

239
Q

Qc:

concs of the reactants and products are not … when the Q value is being calculated

A

constant

240
Q

When Q < Keq, the forward rxn is … –> … than at equilibrium

A

not at equilibrium; higher reactant conc

241
Q

When Q = Keq, the rxn is at …
reactants and products are present in …
… and … are equal

A

dynamic equilibrium;
equilibrium proportions;
forward and reverse rates

242
Q

when Q > Keq, the forward rxn has …
… than at equilibrium
… is increased to restore equilibrium

A

exceeded equilibrium;
greater product conc
reverse rxn

243
Q

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 …

A

pure solids and liquids; activities; 1

244
Q

Keq is characteristic of a specific rxn at a specific … –> …

A

temperature; temp-dependent

245
Q

if the equilibrium constant for a rxn in one direction is Keq, the equilibrium rxn for the reverse rxn is …

A

1/Keq

246
Q

A Keq of 1 can be a valuable reference pt, given that Keq = [products]/[reactants] –> can help us determine if [] of reactants is … or …

A

greater or less than that of the products at equilibrium

247
Q

if conc of products is greater than conc of reactants, Keq will be

A

greater than 1

248
Q

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 …

A

large; positive; less; goes to completion

249
Q

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

A

large negative; one; initial conc of reactant

250
Q

…: if a stress is applied to a system, the system shifts to relieve that applied stress

A

Le Chatelier’s principle

251
Q

Le Chat’s principle:

if reactants are added to a system at equilibrium, … and the rxn will proceed in the … direction

A

Qc < Keq; forward

252
Q

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

A

Qc > Keq; reverse

253
Q

when a system is compressed, its volume … and its total pressure …

A

decreases; increases

254
Q

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

A

partial pressures; total number of moles (check in txt if this is right)

255
Q

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

A

decrease; greater number of moles

256
Q

changing the temperature of a system, unlike the above changes, does not change the …, but rather changes the …

A

Qc; Keq

257
Q

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 …

A

enthalpy; reactant; product

258
Q

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

A

kinetic; thermodynamic; negative

MCAT (11 decks)

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