CHEMISTRY COMMUNITY

Edward Suarez 1I

u know what's a joke?

my grade on that final :(

Edward Suarez 1I

also in general, is the E of a reaction the same for the reverse reaction? or is it negative E

(im probably gonna use this thread to ask questions for myself, pls answer if u need some pts for chem commnunity + ya boi needs help lmao

Edward Suarez 1I

hi so for 14.5d, the answer key says that the cell is Cd(s)|Cd(OH)2(s)|KOH(aq) || Ni(OH)3(s) | Ni(OH)2(s) | Ni (s) i understand how to get the half reactions but i don't understand where KOH came from (i would understand it if it were OH but not KOH). also for the second half of it, how come there i...

Edward Suarez 1I

the question is: write half reactions, balanced equations, and cell diagram of Cl2 + H2 --> HCl how do you find the balance equations (liek i thought it would be Cl2 + 2H+ --> 2HCl but the products for anode and cathode respectively were H+ and Cl, why is it like this? Also how do u know when you ne...

Edward Suarez 1I

if for the reactants it said 2O3, would that be unimolecular or bi?

Edward Suarez 1I

if avogadro calls tell him to leave his number

Edward Suarez 1I

handwritten, mostly writing whats on the slides + adding on with my own notes on the side based on what he says that isn't on the slide

Edward Suarez 1I

two chemists walk into a bar
one says i'll have an h2o
the other says i'll have an h2o too

the second chemist dies...

Edward Suarez 1I

take all ur lame chem jokes and barium

Edward Suarez 1I

doubt it; they never curve tests lol

Edward Suarez 1I

for basic solutions, you use OH- and for acidic solutions you use H+ for balancing purposes

Edward Suarez 1I

Q: What is the chemical formula for "coffee"?
A: CoFe2

Edward Suarez 1I

How about the chemical workers… are they unionized?

Edward Suarez 1I

H2O is water and H2O2 is hydrogen peroxide. What is H2O4?
Drinking.

Edward Suarez 1I

The one that starts with 6 is 6.01 kJ*mol^-1. This is per mole and the one Lavelle used is per gram and isn't given to us on the constant sheet. The two options here are to remember and use that one for this problem or convert the grams of ice to moles and use the 6.01kJ/mol (If you convert to mole...

Edward Suarez 1I

if a king farts, is it a noble gas?

Edward Suarez 1I

what do you call iron blowing in the wind?

FeBreeze!

Edward Suarez 1I

The question requires two equations: Q_{fusion} = mC_{fusion} to turn the ice into water. And Q = mCΔT for heating the water from 0^{o}C to 20^{o}C . The specific heat for water is used because the temperature is not below 0^{o}C . The specific hear for ice is only used till 0^{o}C then in order to...

Edward Suarez 1I

The formula to calculate the heat released is q = m*C*change in temperature. To calculate the heat capacity, C, for a constant pressure, the formula is 5/2R, which gives a value of 20.8 (J/mol)/(degree C). m is for the mass of the substance so you have to get the mass in grams. To do so, you do 5.0...

Edward Suarez 1I

the name's bond, ionic bond.

Edward Suarez 1I

how often do i tell chemistry jokes?

periodically

jk weekly

Edward Suarez 1I

i try to post chemistry jokes but theres no reaction

Edward Suarez 1I

I think the equation goes (Tf-Ti) so for the Copper side it should be (T-100), because both the water and Copper should have the same final temperature at equilibrium. This will yield the 24.8 degrees C. i thought the same but every time i worked it out i always got 19. something... am i doing the ...

Edward Suarez 1I

y'all should zinc of new chemistry jokes

Edward Suarez 1I

when steam makes contact . w/ skin, it undergoes phase transition into liquid . which releases the amount of energy (~41 kJ) for the phase transition into ur skin as heat or something like that

Edward Suarez 1I

i had the same question but I realized that most of the problems that had bar in the question had the answer in bar too

Edward Suarez 1I

NaCl
NaOH

the base is under a salt.

Edward Suarez 1I

anything taught between the last time you turned in homework and when the homework is due should suffice.

Edward Suarez 1I

both require the input of heat to transition into that state (heat needed to make a block of ice into water, and heat needed to make water into vapor)

think irl when u actually you leave ice out and it melts because of heat, or when you boil water

Edward Suarez 1I

Harshita Talkad 4L wrote:x needs to be smaller than 10^(-3) to be ignored. This means it's small enough to be insignificant, which connects to the approximation being valid if it's within 5% because it means the x was small enough.

thank you!

follow up question: what happens if the approximation is not within 5%?

Edward Suarez 1I

what is a cation afraid of?
a dogion

Edward Suarez 1I

did u hear about the chemist who was reading a book about helium? He just couldn't put it down.

Edward Suarez 1I

How small would x have to be to be ignored? (more so talking about when we "ignore x" when it is subtracted from a value when finding Kc for example) and how does this relate to the 5% initial to be a valid approximation?

Edward Suarez 1I

only aq and g solutions are included in the equation (and g is in partial pressure)

Edward Suarez 1I

it depends on the question i think. some questions ask for the concentration of a certain gas in equilibrium, and because gas in equilibrium is given in partial pressure, we need to convert it to concentration.

Edward Suarez 1I

PV = nRT
n/v is concentration, so P = concentration * RT

R is a constant while T is typically given, so typically u can just isolate P or concentration and plug it in to a calculator to find P or concentration from a given concentration or P (respectively)

Edward Suarez 1I

i believe you can use them interchangeably (most people use K only). C refers to concentration while P refers to partial pressure

Edward Suarez 1I

Jackie Ngo 1C wrote:"you must be made of copper and tellurium! because you're so CuTe" ;)

im laughing ur jokes are so funny!!

Edward Suarez 1I

ah i see; i suppose i will just memorize them. thank you!

Edward Suarez 1I

thanks for your responses!

Edward Suarez 1I

what guildelines do we follow to determine the relative strength of bases? I know for acids, it would be amount of oxygen, strength of bond (weaker bond --> stronger acid), etc. but what about bases?

Edward Suarez 1I

how do we find oxidation number? is it something we have to memorize? (like how do. you know the oxidation number of CN is -1?)

Edward Suarez 1I

so Q2 from the midterm stated that "A chemist wanting to determine the molecular formula of gallic acid burned 1.000 g of the compound in an elemental analyzer. The products of the combustion were 1.811 g of CO2 and 0.3172 g of H2O. " how can the products be more than the weight of the rea...

Edward Suarez 1I

take all ur lame chem jokes and... barium!!

Edward Suarez 1I

nvm i read the answer key wrong haha whoops

Edward Suarez 1I

hi what is its hybridization in terms of s p and d?

The answer key (4.33.c) is saying sp3, but wouldn't it be sp3d because of the 3 flourines + two lone pairs. someone help!

Edward Suarez 1I

why isn't the lewis structure of ClCN C single bonded with N on one side and Cl on the other?

Edward Suarez 1I

Jayde Felix 4H wrote:For the sixth edition, the second half of Chapter 3, 6.4-6.5 and 4.1-4.7.

ooh got it, thank you!!

Edward Suarez 1I

what chapter/sections should we read / study if we are using the 6th edition?

Edward Suarez 1I

a chem roast:

you a 10? maybe on a pH scale, cuz you're basic.

Edward Suarez 1I

from friends who have taken the same class, i believe its cumulative!

Edward Suarez 1I

a single paper should suffice!

Edward Suarez 1I

Estelle Jung wrote:Are we able to turn in our homework for Week 8 when we come back from break (Week 9)?

yes if your discussion is during the days off. you'll just have to turn in 14 questions instead of 7 for week 9!

Edward Suarez 1I

i believe that prof. lavelle is trying to finish more in the last few class lectures so we could have class off, but we'll see.

Edward Suarez 1I

dont trust atoms, they make up everything.

Edward Suarez 1I

don't think so but i think he has the right to change the curve at the end of the semester

Edward Suarez 1I

i thought it was based on how each TA grades but i'm probably wrong.

Edward Suarez 1I

Chem_Mod wrote:Given that Monday is a holiday they will be handed back in class next week Wednesday.

will the midterm scores be posted online on myucla/ccle before the physical tests are passed out?

Edward Suarez 1I

Up to what chapter/section of the 6th edition of the textbook should we study? Just want to make sure all the material I'm studying is relevant to the midterm.

Edward Suarez 1I

https://lavelle.chem.ucla.edu/wp-conten ... ns_14A.pdf

it should be in this link!

Edward Suarez 1I

Hi friends, I have a question about Lewis structure: for 3.39, 6th edition: a) NH4Cl has brackets around the NH4 section, but none around Cl. Why is that? How do you know which one to put around a bracket, and how do you know when you need a bracket in the first place? b) for K3P3-, there isnt any b...

Edward Suarez 1I

Hi, so I had a few questions about this problem: What is the ground-state electron con guration expected for each of the following elements: (a) silver; (b) beryllium; (c) antimony; (d) gallium; (e) tungsten; (f) iodine? so particularly, a) the ground state is [Kr] 3d^10 4s^1 instead of [Kr] 3d^9 4s...

Edward Suarez 1I

avogadro reax only

Edward Suarez 1I

Natalie Liu 4I wrote:A neutron walks into a shop and says,"I"d like a coke." The shopkeeper serves up the coke.
"How much will that be?" asks the neutron.
The shopkeeper replies,
"For you? No charge."

haha! that took me a while to understand but eventually i got it.

Edward Suarez 1I

and by quantum world, i mean the first half of it (the topic we are being tested on for the second test)

Edward Suarez 1I

my discussion is on a friday, is it alright if I do homework questions based on quantum world, chapter 2, just for the extra practice/studying rather than on the new material not tested? or do i have to hw based on recent lectures?

Edward Suarez 1I

thank you for the advice! i will def be taking this into consideration in my upcoming test.

Edward Suarez 1I

Ronald Thompson 3I wrote:There's also a list on the 14a quantum world breakdown detailing everything you will need to know how to do for the test.

is this on the textbook? or syllabus? or where might i find this list

Edward Suarez 1I

so test 2 will only be on the quantum world chapter, and none from fundamentals and week 4, right? sorry. just making sure!

Edward Suarez 1I

make sure you complete a good variety of questions from the list of questions he provided us!

Edward Suarez 1I

i try to tell chemistry jokes, but there is no reaction :/

Edward Suarez 1I

will the test give us the formula for the chemicals on the problems or will we have to figure out the formula from the name?

Edward Suarez 1I

looking for one more person for my study group! im a sophomore so another sophomore would be cool since this class is mostly frehsmen ahha

Edward Suarez 1I

did you hear the joke about cobalt, radon, and. yttrium?
it was CoRnY

Edward Suarez 1I

So for this question, it gives us two different reactions where the second one uses the reactants of the product from the first one. When you balance the first one, the products are 2 moles of Fe3O4. and 1 mol of CO2. But for the second reaction, my TA put only Fe3O4 and CO2 and balanced it from the...

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