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MCAT GChem
Term | Definition |
---|---|
temperature | the ONLY way to change a reaction's equilibrium constant is by changing the _________ |
0 | at equilibrium, ΔG = ___ |
+ | regardless of temperature, + ΔH and -ΔS always give a _______ ΔG (nonspontaneous) |
- | regardless of temperature, -ΔH and +ΔS always give a ________ΔG (spontaneous) |
positive, negative | -ΔH and -ΔS: at high temperatures ΔG is ________ and at low temperatures ΔG is _________ |
negative, positive | +ΔH and +ΔS: at high temperatures ΔG is ____________ and at low temperatures ΔG is __________ |
ELISA | preferred method of detecting and quantifying secreted proteins found in the media, blood, or extracellular fluid |
protons | the number of _____ is the atomic number (Z); A C X Z |
neutrons | the number of ______ is the mass number (A); determines isotope A C X Z |
electrons | the number of _______ denotes the charge (C) A C X Z |
bohr | the _____ model states: - e- orbit at fixed differences from the nucleus - e- energies are quantized and are related to their fixed radius orbits |
absorption | the process in which an e- absorbed a specific, allowed quantity of energy; electron jumps from current (ground) states to a higher orbital/state; + change |
emission | the process in which an electron in an excited states drops down to a lower energy state by either a single transition or multiple transition |
dark, bright | in an H absorption spectrum, ______ bands denote where light is absorbed, whereas in an H emission spectrum, _______ denotes where light is emitted |
vibgyor | write out the sequence of the colors of the rainbow from increasing to decreasing energy |
decreases | as energy increases, frequency increases, and wavelength _________ |
quantum | __________ model states: - e- exist within 3D orbitals of various size and shapes - e- energies are quantized and are related to their specific orbital - each orbital can hold 2 electrons: 1 spins up: 1 spins down - s, p, d, f (---> increasing energy) |
1 | the s orbital of the quantum model is associated with how many orbitals |
3 | the p orbital of the quantum model is associated with how many orbitals |
5 | the d orbital of the quantum model is associated with how many orbitals |
7 | the f orbital of the quantum model is associated with how many orbitals |
paramagnetic | this describes an atom in which there's at least 1 unpaired electron --> attracted to external magnetic force |
diamagnetic | this describes an atom in which all electrons are paired up --> repelled by an external magnetic force |
sheilding | describes the electrostatic attraction between valence electrons and the nucleus in any atom; given by Coulomb's law; core electrons protect valence electrons from the full nuclear charge resulting in an effective nuclear charge |
B | which arrow denotes the trend of increasing effective charge across a periodic table A. ↖ B. ↗ C. ↘ D. ↙ |
D | which arrow denotes the trend of increasing atomic radius across the periodic table A. ↖ B. ↗ C. ↘ D. ↙ |
increase | in anions: valence electron repulsion increases, which means ionic radius will ______________ |
decrease | in cations: valence electron repulsion decreases, which means ionic radius will _______________ |
B | which arrow denotes the trend of increasing ionization energy A. ↖ B. ↗ C. ↘ D. ↙ |
ionization | __________ energy describes how much energy it takes to remove a valence electron from an atom |
increases | as positive charge increases, ionization energy ____________ |
electron affinity | this describes the change in energy that occurs when you add an electron to the valence shell |
B | which arrow denotes the trend of more negative electron affinity A. ↖ B. ↗ C. ↘ D. ↙ |
electronegativity | this describes the ability of an atom to attract an electron to itself |
B | which arrow denotes the trend of increases electronegativity A. ↖ B. ↗ C. ↘ D. ↙ |
acidity | this describes the ability of an atom to donate an H+ |
C | which arrow denotes the trend of increasing acidity A. ↖ B. ↗ C. ↘ D. ↙ |
sp, linear | if 2 atoms are connected, it is _____ hybridized and it has a ___________ shape |
sp2, trigonal planar | if 3 atoms are connected, it is ____ hybridized and it has a ________ ___________ shape |
sp3, tetrahedral | if 4 atoms are connected, it is _____ hybridized and it has a _____________ shape |
increases | as the number of electrons shared increases, the bond strength __________ |
increases | as the distance between two atoms decreases, the bond strength _____________ |
endo | breaking a bond is always an _____thermic process |
ionic | if the difference in electronegativity between 2 atoms is big, then those two atoms form an ____________ bond (eg. metal-nonmetal) and the more electronegative atom hogs the electrons |
covalent | if the difference in electronegativity between 2 atoms is small, then those two atoms form a ____________ bond (eg. O2) and the electrons are shared |
solid, aqueous | in ionic bonds, electrons are localized on ions when the molecule is in its __________ phase whereas ions dissociate in _____________ solutions as an electrolyte |
stronger | the larger the charge of an atom, the ___________ the intermolecular force |
harder | as intermolecular forces become stronger, dissociation becomes ______________ |
exo | making a bond is always an ______thermic process |
ion-dipole | ____-_______ forces are produced between an ion and a polar molecule; this force increases with increasing charge |
dipole-dipole | _______-_______ forces are produced between 2 polar molecules; this force increases with increasing polarity; these forces are easily cleaved |
induced dipole | dipole -___________ ________ forces are produced between polar and non-polar molecules; incredibly weak force and can very easily be cleaved |
london dispersion | __________ ________ forces (VdW) are produced between all molecules; force is produced by collision that produce temporary but small dipoles by deforming the electron cloud; very weak and easily cleaved |
H-bonds | _____-_________ form between very polar molecules; a type of dipole-dipole force; force is aligned along the permanent bond dipole; between a donor and an acceptor; happens between H2O molecules |
positive | endothermic reactions have a __________ enthalpy (ΔH) |
negative | exothermic reactions have a ___________ enthalpy (ΔH) |
covalent | __________ bonds are formed between two electronegative atoms, such as nitrogen and oxygen |
non-polar | if the dipoles within a covalent bond are equal and opposite, then the molecule is _____-_________ |
weaker | coordinate covalent bonds are ________ than covalent bonds |
entropy | this describes the potential randomness/unorderedness of a system; |
increases | as the number of particles increases, entropy __________ |
increases | as a molecule moves from a solid --> liquid --> gas, entropy _________ |
increases | as temperature increases, entropy _________ |
gibbs free energy | this is the energy available to do work |
spontaneous | -ΔG describes a ____________ process --> exergonic |
non-spontaneous | +ΔG describes a ____________ process --> endergonic |
negative, spontaneous | if ΔH is negative and ΔS is positive --> ΔG is __________ and the process is ____________ |
positive, non-spontaneous | if ΔH is positive and ΔS is negative --> ΔG is ___________ and the process is ___________ |
negative, positive | if ΔH is positive and ΔS is positive: - at high temperatures ΔG is __________ - at low temperatures ΔG is __________ |
positive, negative | if ΔH is negative and ΔS is negative: - at high temperatures ΔG is ____________ - at low temperatures ΔG is _________ |
fusion | the change in state from a solid to a liquid is known as __________ (aka. melting) |
vaporization | the change in state from a liquid to a gas is known as ______________ |
condensation | the change in state from a gas to a liquid is known as ______________ |
freezing | the change in state from a liquid to a solid is known as ___________ (aka. crystallization/solidification) |
deposition | the change in state from a gas to a solid is known as ________________ |
sublimation | the change in state from a solid to a gas is known as ____________ |
triple | at the ____________ point on a phase diagram, all three phases exist at the same time |
critical | the _____________ point on a phase diagram is the end point of a phase equilibrium curve and afterwards the compound becomes a supercritical fluid |
negative | the key difference in a water phase diagram compared to phase diagrams of other compounds is that the slope of it's melting phase line is ___________ because the density of ice < density of water |
temperature | during a phase change, there is no change in _____________ on a heating curve (flat line) |
slope | specific heat (c) is the ____________ of a temperature (T) v. heat (q) graph |
4 | the specific heat (c) of water is equal to _____ |
increases | as external pressure increases, density ___________ |
decreases | as external temperature increases, density ___________ |
vapor | __________ pressure is the force exerted by the gas particles that vaporize from a solid/liquid sample |
decreases | as intermolecular forces increase, vapor pressure ____________ |
increases | as external temperatures increases, vapor pressure ____________ |
boiling point | the temperature at which condensation/vaporization phase change occurs; vapor pressure = atmospheric pressure |
increases | as external pressure increases, the boiling point ___________ |
increases | as intermolecular forces increase, the boiling point ____________ |
melting point | the temperature at which fusion/crystallization occurs |
increases | for everything except water, as external pressure increases, melting point ____________ |
increases | as intermolecular forces increase, melting point ______________ |
strong | in a solute that is a ___________ electrolyte, complete dissociation of ions occur; eg. ionic salt |
weak | in a solute that is a ___________ electrolyte, partial dissociation of ions occur; eg. weak acids (HF) |
endo, endo, exo | when electrolytes dissolve in water: - first step = agitation; this is an _____thermic process - second step = dissociation: this is an ______thermic process - third step = solvation: this is an _____thermic process |
unsaturated | in an ___________ solution: - concentration < solubility - additional solute can dissolve |
saturated | in a __________ solution: - concentration = solubility - no additional solute can dissolve |
super-saturated | in a _______-__________ solution: - concentration > solubility - precipitate will form if additional solute is added |
increases, pressure | for solid and liquids - as temperature increases, solubility ___________ - solubility is not affected by ___________ |
decreases, pressure | for gases - as temperature increases, solubility ___________ - solubility is affected and directly proportional to ____________ |
soluble, insoluble | solubility rules 1. group I ions, H+, NH4+, NO3-, CH3COO-, and ClO4- are always ___________ 2. Ag+, Pb2+, Pb4+, Hg2+, CO3 2-, PO4 3-, S2- are usually ___________ |
temperature, elastic, high, low | ideal gases assumption s 1. no IMFs 2. average kinetic E is directly proportional to ___________ 3. collision between particles are ____________ 4. ideality is favored with _________ T and __________ P since interactions are minimized |
22.4 | at 1 mole, any ideal gas occupies ________ liters |
volume | Boyle's law states that pressure is inversely proportional to _____________ |
temperature | Charles's law states that volume is directly proportional to ____________ |
temperature | Gay-Lussac's law states that pressure is directly proportional to ______________ |
> | P[ideal] (</=/>) P[real] |
> | V[ideal free space] (</=/>) V[real free space] |
transition states | this point of a reaction coordinate is high in energy, very short lived, can't really isolate them, aka. activated complexes, represent the peaks of a reaction coordinate diagram |
intermediates | this point of a reaction coordinate have lowest energy states, can be isolated, and represent the valleys on a reaction coordinate diagram |
decreases | the rate constant for a reaction (k) is indirectly related to activation energy and _________ as activation energy increases |
increases | the rate constant for a reaction (k) is directly related to the temperature and ____________ as temperature increases |
solids | _________ and solvents are not included in a rate law |
0 | if a pair of rates are the same for 2 different trials, meaning that the rate for a trial doesn't change as the concentration of a reactant changes, than the rate is _______ order |
1 | if a pair of rates have the same ratio as concentration for 2 different trials, for instance if both the concentration of the reactant and the rate double between trial 1 and 2, than the rate is _______ order |
equal | a reaction is in a state of dynamic equilibrium when the forward and the reverse rates are _________ |
temperature | the only thing that can change the equilibrium constant (Keq) is _____________ |
equilibrium constant | the _________ ____________ 1. describes where products or reactants are favored 2. no solids and liquids are included in the expression 3. can only be changed by changing temperature 4. calculated by using equilibrium concentrations |
> | if Keq ____ 1 - products > reactants ∴ products are favored at equilibrium |
= | if Keq _____ 1 - products = reactants ∴ favors neither at equilbirum |
< | if Keq _____ 1 - products < reactants ∴ favors reactants at equilibrium |
reaction quotient | the ___________ _________ (Q) - describes the distance from equilibrium - the ratio of instantaneous product and reactant concentrations |
> | if Q ___ Keq - there are excess products ∴ shift to the left toward the reactants |
= | if Q ____ Keq - reaction is at equilibrium |
< | if Q _____ Keq - there are excess reactants ∴ shift to the right toward the products |
volume, less | if total pressure increases by decreasing _____________ ∴ the reaction will shift toward the side with _________ moles of gas |
volume, more | if total pressure decreases by increasing ____________ ∴ the reaction will shift toward the side with _________ moles of gas |
reactant | if the reaction is endothermic (+H), treat heat as if it were a (reactant/product) |
product | if the reaction is exothermic (-H), treat heat as if it were a (reactant/product) |
reactant, right | for an endothermic reaction: - if you increase heat, you are increasing the amount of __________ ∴ the reaction will shift to the _________ |
product, left | for an exothermic reaction: - if you increase heat, you are increasing the amount of _________ ∴ the reaction will shift to the _____________ |
1/k, multiply | for the forward reaction = k ∴ for the reverse of that reaction = ________ ∴ if you want to combine two reactions, you need to _________ their k's |
< | if Qsp ____ Ksq - there is excess solvent ∴ no precipitate will form |
= | if Qsp ____ Ksq - the reaction is at equilibrium ∴ at its saturation point |
> | if Qsp ____ Ksq - there are excess ions ∴ a precipitate will form |
increases, less, left | The common ion effect says that in a solution with multiple species in chem equilib, adding another species with the same ion _________ its concen. ∴ _______ dissociation occurs because the rxn shifts to the _______ |
donate, accept | Brosted-Lowry acids ___________ a H+ and Lewis acids _________ an electron |
accept, donate | Bronsted-Lowry bases __________ a H+ and Lewis bases _________ an electron |
acids, bases | Lewis _________ are electrophiles and Lewis ________ are nucleophiles |
acidic | more _________ atoms have: - a larger positive charge - are more electronegative - are a larger atom in general |
basic | more ________ atoms - have a more negative charge - are less electronegative - are a smaller atom in general |
products, > | strong acids/bases dissociate more completely ∴ __________ are favored ∴ Ka/b ______ 1 |
reactants, < | weak acids/bases only partially dissociate ∴ ___________ are favored ∴ Ka/b ________ 1 |
false | |
acidic salts | ________ ______ contain an ion that's a weak acid (eg. NH4Cl, FeCl3) !! Group I and II ions are NOT acidic !! |
basic salts | _______ _______ contain an ion that's a weak base (eg. sodium acetate, Li2CO3) !! Cl-, Br-, and I- are NOT basic !! |
acids | H2SO4, HClO4, and HNO3 are strong _______ |
acids | HCl, HBr, and HI are strong _____ |
bases | O2-, OH-, R-, and OR- are strong ________ |
bases | NH2-, NR2-, and H- are strong ___________ |
pH | the _____ scale ranges from 0 (most acidic) to 14 (least acidic) |
pOH | the ______ scale ranges from 0 (most basic) to 14 (least basic) |
buffers | these are mixtures of base and their conjugate acid; minimize change in pH |
decreases, more | if Ka increases , pKa ____________, ∴ the solute becomes ______ acidic |
exo | neutralization reactions are always _____thermic |
7 | for a titration including only a strong acid and a strong base, the equivalence point is where pH = _____ |
> | for a titration of a weak acid with a strong base, at the equivalence point pH ______ 7 |
< | for a titration of a weak base with a strong acid, at the equivalence point pH _____ 7 |
pka | at the 1/2 equivalence point, the pH is equal to the _______ |
oxidation | lose electrons, lose hydrogens, gain oxygens |
reduction | gain electrons, gain hydrogens, lose oxygens |
greater, lesser | the more positive your E° is, the ___________ the reduction potential is the __________ the oxidation potential is |
lesser, greater | the more negative your E° is, the ___________ the reduction potential is the __________ the oxidation potential is |
increases | as electronegativity increases, reduction potential _________ |
reducing | _________ agents cause others to gain electrons and themselves are oxidized (eg. H2, neutral metals, MEHx {NaBH4}) |
oxidizing | _________ agents cause others to lose electrons and themselves are reduced (eg. neutral non-metals, MOx) |
decreases | as free energy increases, E° cell ___________ |
negative, spontaneous | if E° cell > 0 ∴ ΔG is ________ ∴ the cell is __________ |
positive, not spontaneous | if E° cell < 0 ∴ ΔG is ________ ∴ the cell is __________ |
galvanic | a __________ cell - spontaneous - doesn't need a power source - (+)E° cell - discharge battery (like a phone that isn't charging) - aka. voltaic |
electrolytic | a __________ cell - not spontaneous - needs a power source - (-) E° cell - recharging batter (like a phone that is plugged into an outlet) |
positive, negative | in a galvanic cell, conventional (current) flows from the ___________ electrode to the _________ electrode |
negative, positive | in a galvanic cell, electrons flow from the ___________ electrode to the __________ electrode |
reduction | at the cathode in both galvanic and electrolytic cells, __________ occurs (RED CAT AND OX) |
oxidation | at the anode in both galvanic and electrolytic cells, __________ occurs (RED CAT AND OX) |
+, cations | in a galvanic cell, the cathode is the (+/-) electrode; ___________ flow toward the cathode in order to compensate for the electrons entering it |
-, anions | in a galvanic cell, the anode is the (+/-) electrode; _______ flow toward the anode in order to compensate for the electrons leaving it |
negative | in an electrolytic cell, due to the recharging by an added battery, current travels toward the ___________ electrode |
positive | in an electrolytic cell, due to the recharging by an added battery, electrons travel toward the ___________ electrode |
cathode, reduction | in an electrolytic cell, the negative electrode is actually the _______________ and is where ___________ occurs |
anode, oxidation | in an electrolytic cell, the positive electrode is actually the _____________ and is where _______________ occurs |
cathode | plating occurs at the __________ of an electrochemical cell |
anode | pitting occurs at the __________ of an electrochemical cell |
anode | - where oxidation occurs - where electrons flow from - where anions flow toward - where pitting occurs - where O2 is produced in an aq solution |
cathode | - where reduction occurs - where cations flow toward - where plating occurs - where current flows from - where H2 is produced in an aq solution |
titration | redox ____________ are common experiments that produce a change in color to indicate a change in pH; examples are cerimetry and iodometry |
alpha | __________ decay - happens to atoms with a very large nucleus - atomic mass (A; top number) = 4 - atomic number (Z; bottom number) = 2 - least dangerous type of ionizing radiation |
beta - | __________ (+/-) decay - nucleus converts a neutron to a proton - atomic mass (A; top number) = 0 - atomic number (Z; bottom number) = -1 - dangerous - likely to occur for elements with excess neutrons |
beta + | __________ (+/-) decay - occurs for elements with a high proton/neutron content - atomic mass (A; top number) = 0 - atomic number (Z; bottom number) = 1 |
gamma | ___________ decay - nuclei goes from excited to ground state - atomic mass (A; top number) = 0 - atomic number (Z; bottom number) = 0 - for most nuclear reactions - incredibly dangerous with the greatest penetration ability |
long, short | elements with __________ half-lives are safer than elements with __________ half-lives |
10 | how many 1/2 lives do you normally need to pass in order for the element to be deemed safe? |
exo | nuclear reactions are _____thermic |