AP CHEM trends, exceptions, and knowledge you have to know to justify

what is heat fusion?

amount of energy or heat used to MELT a substance, the first horizontal line on the heating curve

heat vaporization is..

amount of heat/ energy used to well, vaporize (turn into a gas) for a substance

represented by the second horizontal on the heating curve graph!

what does it mean if vapor pressure for a substance is low?

the substance is NOT likely to become a gas, as it has very strong IMF forces!

and vice versa if the vapor pressure for a substance is very high!

vapor pressure= atmospheric pressure

this is when the substance boils, evaporation occurs inside the liquid, turning it into water vapor (bubbles)

what happens during sublimation?

where a substance goes directly from a solid to a gas, and the solids can have a vapor pressure (s)→ gas

give me some examples of covalent network molecules, and why do most have Carbon?

Diamond, Graphite, and Quarts (SiO2), SIC

*most of them have carbon becuase it has four available valence electrons, ready to bond

what are the ideal conditions for pv=nrt

high temperature and low pressure

common graph shape when relating volume and pressure

curve downward, not linear straight path, but curve downward, as pressure decreases, the volume is increase and vice versa

relationship between KE and temperature (in pv=nrt)

temperature alone controls the kinetic energy of molecules in any system, in ideal gas law as moelcule volume is negligible in kinetic molecular theory

in the maxwell-boltzman diagram, the lowest peak and widest peak has what property?

it shows us that, the lowest one has the wider range particle distribution, meaning that it’s kinetic energy *sometimes molecular speed, is more, meaning the temperture is higher in that molecule !

using the maxwell boltzman curve we can connnect whichfactors of a reaction

kinetic energy(speed) and number of particles, detmined by temperature

average velocity or speed tells us that→

different from kinetic energy, it is dpeendent on temperatrue, but the mass of the molecules are accounted for instead. Those with a smaller volume are going to move faster, according to the Ke=1/2 mv² equation

why is the ideal gas law not applicable in high pressure scenarios?

this is because, this forces the moleules to have accountable attractions,as the smaller, tighter space is in place, also the collisions are not as elastic as there are other moecules blocking it’s true potnetial

why is the ideal gas law not applicale in low temperature?

under low tempatrue scenaio

what does miscible mean?

solulable in all porportions (able to be dissolved in all porportios… one hundred perent, able to mix well together)

miscible solutions always dissole completely becuase they are solulable in all porportions, this means that they never become saturated? what is the state of saturdation

there is still some substance undissolved, and the process is dynamic as some continue to dissolve and undissolve..

since miscible solutions dissolve all the way, it can’t become saturated

what does it mean a solution is supersatuated

it’s holding too much dissolved solution than it should be able to, this happens when you are heating the soltuion and then lower it

in saturation terms.. gases are

infitenly solulabke in one another

name all diatomic gases (MUST KNOW)

Cl2 N2, Br2, O2, I2, H2,

allows and tell me the difference between them

this is easy

what is the solability rule you must remeber!?

“like dissolves like”

not all molecules can be solulable in water as it’s cation-anion attractions (ionic) are stronger than it’s imf forces with water, what is this becuase of?

coulobmbs law.. the smaller the molecule is, the stronger the ionic bonding, and therefore Ba won’t be forming as strong of a connection with OH, as Mg, as it’s bigger, it will, therefore it be will dissolved and surrounded by water, as the IMF forces will be quite more useful

another way to say that the IMF forces are stronger than ionic forces is to say.. it’s solulable: realte lattice energy and hydration energy

there si mroe hydration energy in the moelcule that is solulbale then lattice energy.

UV spectropsoy can be used to see/find

see different transtion in energy levels, and find concentrations of solutions

infrared spectrocopy is used to find

detect prescnece of diff type of bonds and to identify molecules

*known as the vibrational

Microwave spectroscopy is used for is used for

rotation of polar molecules

condensation is a what kind of process..?

exothermic because when gas becomes a liquid, the molecules go closer togehter, releasing energy (yay)

keep in mind that condensation is when gas becomes liquid

what increases collision rates? and how do tehy increase reactionrate

-increasing concentration of reactants

-increasing surface area,

-increasing temperature,

they all increase the collisions between molecules and thereofore increasing the chances of a reaction happening and sufficeint energy during movement as well→ increasing reaction rate

at the half-equivalence point in a strong base weak acid titration, what is true about the concentrations of the weak acid and conj base

they are equal to eachother as the strong base has neutralzie the weak acid , and this is where pka=ph

remeber this is also wehre the buffer solutioni is !

buffer solution

has lots of weak acid and it’s salt (conjugate base)

best buffer when the concentrations of conj base and weak acid are equal, in hasselbach

pka=ph

best indicator?

at equivalence point, the pka of indicator matches the pH of the reeaction~!

We uses Hess law type of order of operations for which type of equations

enthalpy and Gina’s free energy

When manipulating equations for unit 7, what are the major rules

When reversing, you reciprocate the K value, when doubling or multiply the concentrations, you raise the number to the number of, and when adding together, they are multiplied together not ADDED like Hess’s law

what makes reaction tdf if h is negative

if entropy is positive, this is always TDF

if h is positive and s is negative, the opposite of tdf at all times this means.

the reaction is never at tdf

is s is negative, than h has to be what to make g<0

h has to be negative, and this is only tdf at low temperaturees! don’t want to overide

is h is positive what does s have to be

positive, and this is only favored at high temperatures since h is quite high

+H +S

TDF AT HIGH TEMPERTURES

-H+S

always TDF

-S -H

TDF AT LOW TEMPERATURES

+H +S

TDF AT HIGH TEMOERTURES

ideal gas law

high temp low pressure!

what will happen to total pressure and partial pressure of a certain gas container if everything remains constant, and I added an inert gas

adding an inert gas like, noble gas law, will increase the total pressure, as there is more gas molecules inside, but the partial pressure of the original gas will remain constant. (it’s mole fraction goes down, but due to exception, it’s partial pressure remains the same)

in electroloytic cells, we have to consider what?

we have to consider the water for the reduction reaction! (the other element doesn’t/isn’t always 100% reduced)

tell me what happens in concentration cells when q>1 (when there is more concentration of products)

when q>1, the cell potential is negative, according to the nernst equation. the reaction will flow towards equillbrium, that is shifted to the left (anode) and this will make this overall cell potential engattive, as there isn’t as much V.

tell me what happens in a q<1 cell?

this means that there is more of anode, then cathode, soincreasing the cell potential overall the reaction wills shift to the right, making more cathode,

what does first ionization energy mean?

the amount of energy to remove the first electron? and so on.. when looking at a ionization energy table chart, you are able to tell that the first electron, so when approaching an E=hv problem, make sure to realize if it saying first ionization energy, it is ONE atom so divide by avagadro’;s number which is )6.02 × 10 to the 23!