CHEMISTRY COMMUNITY

Esther Kim

Check out the outline!

Esther Kim

The greater the disorder, the higher the entropy! Hope this helped

Esther Kim

Lavelle said that we can assume that all gases act as ideal gases in this course so Pv=nrt can be used

Esther Kim

These are so good! Keep em going

Esther Kim

When I took 14A, I was super rusty on old high school chem. The modules on Lavelle's website are a genuine lifesaver to be honest

Esther Kim

deep breaths and maybe telling yourself some calming mantras throughout the final

Esther Kim

Wasn't able to attend but I'm glad to hear everyone had fun!

Esther Kim

Happy Late Valentines Day in March <33

Esther Kim

[A] = -kt + [A]0
^ You can use this equation and plug in the values

Esther Kim

yes! The catalyst is needed to start the reaction so it will mostly appear in the first step

Esther Kim

They can be either or. It just depends on what you're given in the problem

Esther Kim

Esther Kim

K is negative because the concentration of the solution is decreasing as the reaction proceeds

Esther Kim

They speed up the reaction by lowering the activation energy

Esther Kim

More complex models result in higher A values
while as more simple (symmetrical) would result in lower A values

Esther Kim

You can just remove A from the equation because its the same for both the catalyzed and uncatalyzed

Esther Kim

can only use 5/2C and 3/2C for ideal monatomic gases

Esther Kim

U=q+W

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Used when there is constant external pressure or when volume changes

Esther Kim

What is the chemical formula for a banana?
BaNa2

Esther Kim

q=mCΔT is used for mass q=nCΔT is used for moles

Esther Kim

Temperature increase in an exothermic reaction results in a decrease in K

Esther Kim

Q<K it means then it will proceed towards the forward direction while as if Q>K then the reaction will proceed in the reverse direction

Esther Kim

Kc is used for concentrations! Kp is used for partial pressures!

Esther Kim

lone pairs count as a sigma bond!

Esther Kim

If you're given a diagram, the right cell is the cathode and the left cathode is the anode
However, if given just equations, the higher reduction potential is the cathode while the other is the anode

Esther Kim

You don't need to but you should! That way you can balance charge a lot easier

Esther Kim

You can find n by balancing the half-reactions. Once you multiply the equations so that the electrons cancel out, that final e- value is n

Esther Kim

The difference between balancing redox reaction in an acidic vs a basic solution is at the end of the process. After you balance the half-reactions and combine it for the full balanced equations at the end, you add as many OH- to both sides as there is H+. Afterward, you combine the OH- and H+ on on...

Esther Kim

E°=0 only in concentration cells

Esther Kim

catalyst is used in the beginning and is in the final equation. However, the intermediate disappears during the process

Esther Kim

higher the reduction potential, the more likely it will be reduced by the oxidizing agent

Esther Kim

t's certainly possible to have negative pH or pOH, we just don't see it very often. All it means is that the molarity of the solution is greater than 1, so the solution will either be very acidic or basic depending on if it's pH or pOH. Yes very possible! It just means that the molarity of the solut...

Esther Kim

Only used for ideal monoatomic gases !

Esther Kim

Delta G is the free energy available at any given moment but ΔGº is the free energy available under standard conditions

Esther Kim

it would be positive

Esther Kim

Finding Oxidation numbers is a long process with many steps: However, there are many resources that you can use to help you understand the rules!!
I recommend this video by organic chemistry tutor: https://www.youtube.com/watch?v=j0hI-a6EWWo&t=349s

Esther Kim

The endothermic process can be spontaneous when the entropy increases. The process will be spontaneous above a certain temperature

Esther Kim

Degeneracy is the number of formations that a system can achieve the same energy state. You need to consider the number of positions and moelcules.

Esther Kim

Increase in T will increase K because the atoms will be more likely to collide

Esther Kim

I was confused by this too !
n=# of electrons transferred in the final combined equation (sum of half reactions)

Esther Kim

You can figure this out through two methods! 1. Change in Gibb's Free Energy (Delta G) : A (-) Change in Gibb's free energy means that the system is spontaneous A (+) Change in Gibb's free energy means that the system is nonspontaneous 2. Change in Entropy (Delta S) : A (+) Change in Entropy means t...

Esther Kim

When writing the half-reactions, including electrons are necessary because you need to balance the charge
However, the final equation should have the electrons on either sides canceled out

Esther Kim

Extensive properties are dependent on the volume of the system
Intensive Properties remain constant no matter the volume of the system

Esther Kim

Bond Enthalpies = (sum broken bonds) - (bonds formed)
Positive or Negative depending on values of either

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Delta H (-) = loss of heat
Delta H (+) = gain of heat

Esther Kim

If Volume increases, pressure decreases
If Volume decreases, pressure increases

Esther Kim

Kw is the equilibrium constant of water (or dissociation of water) = 10^-14 at 25 celsius
Some other relationships include:
- pKW= pOH+pH

Esther Kim

Solids and liquids show insignificant change in partial pressure so they aren't included in K !

Esther Kim

For Ice Tables we use M

Esther Kim

delocalized pi bonds are in resonance strucutres. meaning the electrons move freely

Esther Kim

he hybridization would be sp3d2

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polar bonds share electrons unequally while nonpolar share electrons equally.

Esther Kim

use the equation FC=V-(L+S/2).

Esther Kim

Double bonds are stronger and therefore bring the atoms closer together.. so it's shorter

Esther Kim

A ligand is a species that donates both of its e- in order to form a coordinate covalent bond. This can be a neutral molecule like ammonia (NH3) or an ion like Cl- .

Esther Kim

Daniela Contreras 3E wrote:Hey guys remember: don't trust atoms, they make everything up!

good one

Esther Kim

The stronger the bond the higher the melting point

Esther Kim

Yes bc hydrogen bonding is dipole dipole

Esther Kim

Nima Ghorashi 3A wrote:Friend: "Johnny, why have you been so upset and frustrated lately?"

Johnny: "Well, I have taken two years and a quarter of chemistry, and I have yet to get this girl's significant digits."

good one

Esther Kim

Method 2 is probably the best one to go with because Method 1 only works if there is a 1:1 ratio.

Esther Kim

Knowing the basic nomenclature could help but probably not necessary to memorize the more obscure ones

Esther Kim

there really isn't an order (as previous posts have mentioned) but it's just easier to start off with the species that occur the least in the chemical equation

Esther Kim

You should be able to balance every chemical equation

Esther Kim

Multiply them til you get a number that you're sure you can round up or down

Esther Kim

the theoretical yield is the product based off of the limiting reactant

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Protonated means the addition of H+. So acids protonate bases

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When the compound has a negatvie charge

Esther Kim

Delocalized are in resonance structures while as localized are in single, double, and triple bonds

Esther Kim

You count the regions of electron densities (bonds and valence electrons) in the lewis structure to determine hybridization.
sp = 2 e- regions
sp2 = 3 e- regions
sp3 = 4 e- regions
dsp3 = 5 e- regions

Esther Kim

they be the same

Esther Kim

Hella practice problems or... just taking a warm [censored] shower or taking a walk?

Esther Kim

Thank You Dr. Lavelle, Thank you for genuinely caring for your students and teaching us Chemistry 14A. Your passion for the subject shines through and your accent makes listening to the lectures that much better <3 Thank you for everything and I can't wait to have 14B with you next quarter ! Best, E...

Esther Kim

You look at electronegativity. If it's greater than 2 then its ionic while as if it's less than 1.5 than it's covalent

Esther Kim

Yes the valence electrons are the dots in the lewis structures

Esther Kim

No double bonds always have one sigma and one pi bond
triple bonds always have one sigma and two pi bonds

Esther Kim

A single bond always has one sigma bond
double bond always has one sigma bond and one pi bond
triple bond always has one sigma bond and 2 pi bonds

Esther Kim

Thank you !!

Esther Kim

The work function is the minimum energy required to eject an electron!

Esther Kim

It's provided on the constants/equations sheet for the tests !

Esther Kim

I learnt the equations the best by writing them down before plugging in numbers in practice problems.

Esther Kim

I recommend looking over the outlines to figure out what to study. However, probably focus the most on quantum since we spent the most time on it

Esther Kim

Yes both midterm 1 and midterm 2 material will be covered on the final but I believe the # of questions from each section depends on the amount of time we spent on it. So expect a lot of questions from Quantum

Esther Kim

I personally have turned in homework a day or two later and didn't have any points docked on CCLE

Esther Kim

s=1 orbital, d=10 orbitals, p=6 orbitals, f=7

Esther Kim

electron affinity is the energy required for an atom to add an electron and ionization is the energy required to remove an electron

Esther Kim

a freak ton of practice problems to reassure myself that I will do well on the test

Esther Kim

"Sodium, Bromide, Oxygen"
"Na BrO"

Esther Kim

Anna Hilger 2G wrote:I laughed way to hard at this.

LMAO iconic

Esther Kim

I tried to make a clever chemistry joke but all the good ones...
ARGON

Esther Kim

molecular structure comes from lewis structures and the # of electrons

Esther Kim

Actual yield is normally never greater than the theoretical yield

Esther Kim

No you don't need to memorize the periodic table

Esther Kim

Yes you're correct :)

Esther Kim

protonated is the adding of protons while as ionized is the removing/adding of electrons

Esther Kim

Reading the textbook helps me understand the material a lot more in depth

Esther Kim

thank you for the advice :))

Esther Kim

If you look at the # of lone pairs, you should be able to determine if it's monodentate, bidentate, etc.

Esther Kim

The chemical structure CCL2H2, couldn't it be nonpolar if the CL's were on opposite sides? Why is the right structure in the book the structure in which the Cl's are next to each other?

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