AP Review Flashcards

For best experience use only multiple choice and definition questions only

Acid base rxns are characterized by….

proton transfer

What is the formula for mass percent?

mass of thing / mass of soln the thing is in * 100%

Why can’t galvanic cells be done in the same chamber without a semipermeable membrane

because it results in somewhat of a short circuit. the resulting rxn’s electrons will not travel through the wire

the semipermeable membrane would allow ions like ions from the anode material, or from the cathode soln to travel through and neutralize the other side

Why can electrolytic cells be done in the same chamber (with a semipermeable membrane)?

power is supplied. it won’t result in a short circuit, and the membrane prevents mixing of products (esp. gases like o2 and h2 for pure water electrolysis)

Electrons flow this way in a traditional cell

From the anode to the cathode

Why isn’t a salt bridge necessary for an electrolytic cell

a salt bridge isn’t necessary because power is supplied and thus the reaction should continue as long as there is power

What does the salt bridge do?

It maintains neutrality between the two chambers to keep the reaction going

this is because cells are usually filled with not pure metal. it usually splits into something like Al and NO3- (in the cathode), and as Al+ leaves the soln, the solution becomes more negative and this prevents electrons from coming through

in the anode the electrode degrades and makes the soln more positive

What is the stationary phase in chromatography?

The phase that doesn’t move and is usually polar, attracting other polar things. This is usually silica

What is formula for Rf value?

distance traveled by compound / distance traveled by solvent

Do polar compounds make Rf lower or higher

Lower

Nonpolar compounds make Rf values

Higher

Why can’t Rf > 1 happen

because the distance traveled by the compound cannot exceed the distance traveled by the solvent front in chromatography.

What is the titration’s equivalence point?

When the amount of added titrant is stoichiometrically equivalent to the analyte, when the soln changes color

Difference between titration endpoint and equivalence point

endpoint is physical color change and equivalence point is theoretical

Infrared waves impact on electrons or atoms

Will cause vibrational transitions in molecules, leading to increased kinetic energy.

Ultraviolet waves impact on electrons or atoms

can cause electronic transitions, allowing electrons to move to higher energy levels or even ionize atoms.

Visible light impact on electrons or atoms

can excite electrons from ground states to higher, but not necessarily ionizing levels.

X-rays impact on electrons or atoms

can ionize atoms by ejecting inner-shell electrons, leading to potential creation of ion pairs.

Microwaves / Radio waves impact on electrons or atoms

can cause atomic nuclei to resonate, leading to rotational transitions in molecules.

On an absorbance concentration graph the slope is

equal to molar absorptivity times path length

optimal way to measure the concentration of anything with different wavelengths

stay out of the absorptivity of other substances present in the substance

where does oxidation happen

anode

where does reduction happen

cathode

electrolysis is only done by…

electrolytic cells

what determines which half reaction is in the anode

whichever one has the lowest standard reduction potential

In a current, moles of X produced are equal to

current * time all over mol of electrons times faraday’s constant

unlike nonstandard g, standard g tells you the rxn’s

favorability

nonstandard ∆g tells you

the spontaneity

in a cell diagram shorthand, this is always written first

the anode

cell diagram shorthand looks like

anode material | substance in anode container || (salt bridge) stuff in cathode container | cathode material

if we have two electrodes of the same material then

the concentrations of the anion/cation must be different, anything else and the potential is 0

if the concentrations are different, e.g. by pouring different concentrations of solns or just a concentrated soln in to one of the chambers, then the electrode at one end will try to dilute itself by building electrode and one will try to concentrate soln by removing electrode.

in galvanic cells, if inert electrodes aren’t used, then what degrades over time and what builds up over time

The active material at the anode degrades while the material at the cathode builds up.

standard conditions mean

a temperature of 25°C (298 K), a pressure of 1 atm, and concentrations of 1 M for solutions.

STP means

Standard temperature and pressure, defined as 0°C (273 K) and 1 atm.

in a galvanic cell what is positive and what is negative

cathode is positive and anode is negative, as the electrons are being forced uphill by the power source (as the rxn is likely unfavorable, so the situation flips to make it favorable regarding standard reduction potentials)

in an electrolytic cell what is positive and what is negative

the anode is positive and the cathode is negative

e cell equation

e cathode - e anode

∆G standard tells the

favorability

characteristics of ionic solids

high melting point, conductive in water, britttle

characteristics of metallic solids

variable melting, but usually high, good conductor, and malleable, shiny and opaque

characteristics of covalent solids

hard (except for graphite) and high melting points, bad conductors

amorphous solids

no specific melting points, forms jagged edges when broken.

neat arrangement

crystalline

not neat arrangement / with kinks

amorphous solid

more surface area means for intermolecular forces

more ldfs

if something makes the rxn spontaneous or favorable…

then it is considered to be the one that “drives” the rxn

polyatomic ion charge equals

formal charge of all the things inside

elements from what period can expand their octets

periods 3 and higher

extra charge usually goes on the most

electronegative atom in the polyatomic ion.

lewis structure steps

1. find central atom

2. draw single bonds

3. fill in the outer atoms’ shells

4. extra electrons to center atom

5. minimize formal charges with double bonds / whatnot

on a pressure time graph the slope is

rxn rate

on a pressure time graph if it plateaus exponentially its probably this order of rxn

first

if its linear on a pressure time graph and then suddenly plateaus its probably this order of rxn

zero

units for zero, first, and second order rxn rates

M/s, 1/s, and 1/Ms

acidity periodic trends

right side is most acidic, and increases as atomic radius increases if acid is able to be formed. this isn’t true for all acids, e.g. oxoacids increase with number of oxygens

basicity periodic trends

usually left is most basicand decreases down a group as the size of the atoms increases, making it harder to gain protons.

atomic radius periodic trend

increases down a group and decreases across a period due to increasing nuclear charge.

if an ion does these things then it isn’t a spectator

changes state, changes oxidation state, or forms a precipitate.

M1V1/n1 = M2V2/n2 tells you

the relationship between molarity and volumes of solutions in dilution or titration. n is the stoichiometric numbers in front of those substances

valence electrons are the

highest energy ones

if K increases with temperature then the rxn is

endothermic.

dissolve or dilute first to prepare soln?

You should dissolve the solute first before diluting to ensure complete dissolution and accurate concentration.

sublimation is

solid to gas

deposition is

gas to solid

way to form buffer with weak + strong

ionize half of all the moles of the acid

in a rxn with ∆H_rxn, formula?

mol mol_rx / stoichiometric coefficient times ∆H_rxn = energy released, moles should be the limiting reactant. not the other ones

∆H rxn regarding bonds

broken - formed

binding energy does not affect….

intensity of the photoelectron spectrum. it determines their position on the x axis

ideal gas behavior is

lower pressure high temps,

small volume

no intramolecular forces

low polarizability

if Qsp > Ksp

the soln is supersaturated and forms a precipitate

if Q>K

the reaction favors the reactants

homogeneous rxn

is a reaction that occurs in a single phase, either all gaseous, all liquid, or all solid.

heterogeneous rxn

is a reaction that occurs between two or more phases, such as solid, liquid, or gas, where the reactants are in different states.

if we add too much titrant what happens to our calculated moles

we overestimate the amount of analyte present.

if the indicator’s color range matches the equivalence point

color change will be sharper

bimolecular

reaction involving two molecules in the rate-determining step (usu. reactant stoichiometric numbers added up)

unimolcular

same thing as bimolecular but just one

For aA + bB → cC + dD what is rxn rate

rate = -1/a * [A]/∆t= -1/b * [B]/∆t = 1/c * [C]/∆t = 1/d * [D]/∆t, it tells you the ratio of speeds between different participants. negative is for reactants because it disappears usually

for x+y→ products

k[x]^m [y]^n = -∆[x]/∆t = ∆[y]/∆t

unique rxn rate units

molarity per second (M/s) or concentration change over time or moles per lliters per second (m/L/s)

for rf values more polar solvent (not compound) means

higher rf values in TLC

for rf values more nonpolar solvent (not compound) means

lower rf values in TLC

the avearge speed of gas is higher when the molelcule is

not polar and less mass, higher temperature

ideal gas behaviors

are observed under low pressure and high temperature conditions, where gas molecules act independently and intermolecular forces are negligible.

If a change in temperature of 10 degrees was found to triple the rate of rxn…

the number of molecules above Ea increased, ideally to 3x. rxn rate is directly proportional to the number of molecules above the activation energy

every 10K increase in temperature will (do to rxn rate)

double the reaction rate. this may not be true for things that have high E_a, in which case it may triple or quadruple the rate, and vice versa.

graham’s law says

lighter gas escapes faster from tiny hole, or rate1/rate2 = √(m1/m2)

what is mole fraction

the ratio of the number of moles of a component to the total number of moles in a mixture.

all mole fractions must add up to one (in a molecule)

gas constant for torr / mmhg

R=62.3637 L*mmhg / K * mol

do ideal gases have mass

yes. but they have no volume

molar volume of ideal gas at stp?

22.4 liters/mol

what does lower boiling points mean for vapor pressure

higher vapor pressure

density dependent factors

regulate population growth based on density. like competition, predation (since more prey = predator population increase), disease, food, and waste accumulation.

density independent factors

regulate population size no matter what density, e.g. other animals barging in and destroying the habitat, natural disasters, earth exploding, climate, and sunlight (as a resource. it is kind of a dependent factor also. but sunlight provides equal light to all, and it doesn’t lower its brightness).

in the etc, more heat is produced when

more electrons are processed and proton leakage

what kind of inhibitor is it if the concentration of the substrate has no effect on it?

allosteric inhibitors

in hardy weinberg calculations, q is….; and q² is…..

the frequency of the recessive allele; the frequency of the homozygous recessive genotype

properties of water

high specific heat

ice being less dense

cohesion/adhesion

cholesterol at high temperatures…

reduces fluidity of the membrane

cholesterol at low temperatures…

increases fluidity

allele fixation can happen when

genetic drift or other factors contribute to one allele becoming too good. happens most significantly in small populations, often seen with the bottleneck or founder’s effect