CHEMISTRY COMMUNITY

Sarah Hernandez 1F

As of right now I think UCLA is planning to have in person classes, but it seems like they're considering hybrid and fully remote too based on that survey they sent out. I'm hoping to be on campus and take at least some in person classes, but if things ended up being fully remote I would just stay h...

Sarah Hernandez 1F

Isabelle Hales 1J wrote:Going off of this, will the catalyst have the same effect on both the forward and reverse reactions? In other words, is the increase in speed because of the catalyst the same for both reactions? Thanks!

yes I believe the increase in speed is the same for both the forward and reverse reactions

Sarah Hernandez 1F

if it helps, on the Constants and formula sheet the half life for the first order is on the third from the bottom row of equations, second in the second from the bottom, and zero order is the second equation on the very bottom of the sheet, all denoted with t1/2

Sarah Hernandez 1F

If you set your alarm on your phone or something else connected to the internet it should automatically adjust to daylight savings and go off at 8am!

Sarah Hernandez 1F

Thanks you guys your comments were really helpful!

Sarah Hernandez 1F

For this problem I keep getting the same answer, 1.01x10^-5, but it says it's wrong and I'm not sure what my mistake is. I'm using the Arrhenius equation, divide k by A and then do ln(k/A) to get -E/RT and divide the number by 8.314 for R and -342 K to get the activation energy in joules, then divid...

Sarah Hernandez 1F

Xinying Wang_3C wrote:I always start with O which is always -2, then H is often +1, any solids are 0. Then some really frequent ones, like Na,1+, Mg 2+ Ca 2+, Cl-, OH-, then you should be good for most of the cases to figure out the rest of elements' oxidation numbers.

This is really helpful thank you!

Sarah Hernandez 1F

I think I manage burnout by making sure I at least stay productive, so if I'm not doing schoolwork I try to work on my hobbies. I like to bullet journal so that's kind of doubly useful since once I'm done I can use it to plan out my time and get important due dates down.

Sarah Hernandez 1F

I've heard that we'll be done by Wednesday, and while I think there will be some chemical kinetics make sure you review everything else we've learned

Sarah Hernandez 1F

I think because it's cumulative most of the material on the final will match the amount of time we've spent learning it on class, but with maybe a bit of emphasis on the newest material since we haven't been tested on it yet

Sarah Hernandez 1F

I get financial aid too, and I wanted to take summer session as well I already enrolled in my classes, and then a new bill thing will show up on your bruin bill. It'll tell you how much the classes are total. Just know that if you unenroll in all your summer classes its a 150 dollar fee. Yeah and t...

Sarah Hernandez 1F

Kyle_Lee_2B wrote:I believe 5.25 is the incorrect E, instead use 1.94. You probably used a function for the two energies. For example probably used Fe^3+ instead of Fe^2+

Thank you I got the right answer now!

Sarah Hernandez 1F

I believe it should just be 2Fe2O3 dot 3H2O, the full equation I got was 4Fe+ 3O2 +6H2O -> 2Fe2O3 dot 3H2O, hope this helps!

Sarah Hernandez 1F

I don't know what mistake I'm making but I'm still not getting the right answer so please help.
I have E=5.25
R=8.314
T=298
F=96485
n=2
Q=48 so ln(Q)=3.8712
and when I plug those into E= E-(RT/Fn)ln(Q) I get 5.20

Sarah Hernandez 1F

Thanks for your help guys!

Sarah Hernandez 1F

For this problem I can't figure out how to balance the equation. I think I'm getting confused on what to do with the H20 and OH- in the beginning but I'm not sure. I got the oxidizing and reducing agents right but now I don't know what to do.

Sarah Hernandez 1F

I'm content with my score, not as good as I was hoping but still not too bad so now I just need to worry about the final, I think I'm in better spot now than I was in 14A

Sarah Hernandez 1F

Darren1j wrote:It says 14c will be "online," but will the recordings be posted as well?

I think I've heard that they will be

Sarah Hernandez 1F

I think it should be fine, you're supposed to post questions in the right topic so if that means posting in 14A then you probably should

Sarah Hernandez 1F

I really like hot and sour soup and sushi

Sarah Hernandez 1F

Great job guys! Take some time to relax but also don't fall behind!

Sarah Hernandez 1F

I'm all done with my midterms now so I'm catching up on my shows and working on my crochet project

Sarah Hernandez 1F

I'm taking 14c next quarter and probably 14bl over the summer

Sarah Hernandez 1F

yes! it's now due on Wednesday at midnight!

Sarah Hernandez 1F

Thanks for posting these tips! Just adding that I also like to read through the textbook for topics that I'm less confident since I find the explanations in there very thorough

Sarah Hernandez 1F

I'm planning on taking bl over the summer and c in the spring!

Sarah Hernandez 1F

I'm constantly watching leverage since it's like my favorite show ever, and I'm watching horimiya as the episodes come out

Sarah Hernandez 1F

Hi! So first you can assume qwater= -qmetal, and since q=mcdeltat you can plug in the values you know and solve for the final temperature which is the same for both the water and iron

Sarah Hernandez 1F

I find reading the textbook helpful because it's very detailed

Sarah Hernandez 1F

Eliana Witham 2H wrote:For #10, I actually did put a negative in front of q(water). I used the equation deltaH(fusion) + q(ice) = -q(water). This equation worked for me!

same I used -qwater and got it right

Sarah Hernandez 1F

It really helps if you write everything out, firstly just get the different equations in the right directions and then multiplying them to get the right constant values so things cancel out and making sure to do the same to the deltaH values

Sarah Hernandez 1F

Have you set it up so that deltaHfusion+ qice= -qwater? When you do you an just solve for Tf

Sarah Hernandez 1F

Gabe_Ek 1G wrote:I believe K would stand for Kp which is in regards to the equilibrium constant for pressure and Kc for molar concentrations.

K is just the general equilibrium constant and could be either Kp or Kc I believe

Sarah Hernandez 1F

Late response but after the midterm I made myself some lunch and then took a nap

Sarah Hernandez 1F

Congrats everyone!!

Sarah Hernandez 1F

Jessie Hsu 1C wrote:I agree, I felt a little rushed this time but definitely not as much as during the final last quarter. I think doing the textbook problems really helped though!

I agree, the timing was better for me than the final but I didn't have as much time as I did with the midterms last quarter

Sarah Hernandez 1F

This is a problem that I used to have a lot on multiple choice exams. My recommendation is that if you run into a problem that seems to be very mathematically involved, skip it and come back to it at the end. Ultimately, you will be able to answer more questions this way because you will be able to...

Sarah Hernandez 1F

Assuming all your numbers are correct, you should multiply the number on the left hand side of the equation by 0.75-x to get a quadratic equation and then use the quadratic formula to solve for x, which should be a positive value and equal to [H+]. Then to get the percent ionization divide the value...

Sarah Hernandez 1F

When did you purchase it? If it just arrived and isn't working you should definitely get in contact with the UCLA bookstore assuming that's where you bought it

Sarah Hernandez 1F

I listen to a lot of different music but my favorite artists would probably have to be MARINA, Hayley Kiyoko, bts, Agust D, and recently I've been getting into Rina Sawayama. Kinda random too but the soundtrack for into the spiderverse is one of my favorite albums so I definitely recommend checking ...

Sarah Hernandez 1F

I also faced some difficulties while answering this question. What should we consider as included in the solution in NaClO? I'm confused by the wording of this question. The way I understand it is that the solution in NaClO includes the NaClO and H20, however as the person above mentioned the NaClO...

Sarah Hernandez 1F

Janna Shakiba wrote:Does anyone know why it's not open book? Weren't the 14A midterms open book?

The 14A midterms last quarter were not open book

Sarah Hernandez 1F

I think you made a mistake towards the end because the xs shouldn't cancel out like that and I believe it is that the coefficient of x on the left side of your equation shouldn't be 2, it should be 1.33, and with that you can just get x on one side and solve for it

Sarah Hernandez 1F

I have the same issue with CCLE saying I got 80% on the assignment when I got 100% on Sapling. I'm just worried because I don't know which questions it has counted as 'incorrect' as Sapling isn't giving me any indication - I was wondering if you were able to resolve this issue, and if you know why ...

Sarah Hernandez 1F

With the Kp and an ICE table you should solve for the partial pressures of the reactants and products, considering the fact that Kp is the pressure of the product over the pressure of the reactants, you can solve for x and then you can find all the partial pressures at equilibrium. Then you just nee...

Sarah Hernandez 1F

I'm pretty sure we're technically only supposed to be using scientific calculators however any calculator was allowed during last quarter and I'd assume that policy will remain the same. Yeah that's what I remember too, my TA really wanted us to use scientific calculators and if you didn't have one...

Sarah Hernandez 1F

Like other people said, you should definitely try to get five posts each week but sometimes they don't seem to actually count it as long as you have 50 by the end of the week. That being said, I think since you just joined the class you should try to catch up to everyone else asap, like having 10 po...

Sarah Hernandez 1F

In general, I've found that taking notes on the lectures and readings in the textbook make me pay more attention to the content, and when you're trying to review going through the outlines on the website is really helpful if you first go through and try quizzing yourself because then you can figure ...

Sarah Hernandez 1F

Sapling is our graded homework but it's only graded on completion! The textbook problems given in the outlines are the ones for extra practice and are optional Sapling is graded on correctness, you just have unlimited attempts on the questions but make sure to get the right answers if you want full...

Sarah Hernandez 1F

Hi! so to solve this first I would write out that 53.5=[HI]^2/[H2][I2] and the ICE table with the concentrations of H2 and I2, which are both 0.4, and HI would be 0, and so you know H2 and I2 would both lose x while HI would gain 2x but you don't know the value of x, so you can plug in 2x for [HI] a...

Sarah Hernandez 1F

You should be able to use moles or concentrations/pressures if the volumes are the same in the ICE tables

Sarah Hernandez 1F

Doing the textbook problems on the outline is probably one of the most helpful things, and I'd honestly recommend reading through the recommended textbook sections at some point too, maybe when you're reviewing for the midterm or final, because I've found that the information they contain is really ...

Sarah Hernandez 1F

I have a few, working on my studying habits, fixing my sleep schedule, and I'd really like to be able to work on my hobbies more

Sarah Hernandez 1F

That sounds really helpful please let me know if you end up doing this!

Sarah Hernandez 1F

Amanda Bueno-Kling 2L wrote:I know course evals were extended, but when do they close? I also forgot to do them, but will do them if they're still open.

I think they closed Wednesday/this morning

Sarah Hernandez 1F

That sounds so fun! I'm planning on sleeping and catching up on some shows and books I've been meaning to watch and read

Sarah Hernandez 1F

I'm planning on binge watching some shows, painting, and probably baking some new recipes I found!

Sarah Hernandez 1F

Thank you for this!

Sarah Hernandez 1F

Hi! Like others mentioned, Toolbox 9C.1 in the textbook and Table 9C.1 are pretty helpful for this question. But this is how I approached the problem: We would start with the part inside the brackets, [Co(NH3)5Cl]. There are three separate components: Co, NH3, and Cl. We know that Co is the transit...

Sarah Hernandez 1F

I'm going through the book and taking notes based on what the outline says we need to know and doing the textbook problems after I finish going through a section of the book to make sure I know what I'm doing. I'm also going to try to attend the review sessions and maybe rewatch some lectures on top...

Sarah Hernandez 1F

Hi! So first I would identify the metal, which is M here, and then try to identify how many atoms/molecules would be bonded to it. Here, each CO counts as 1 and each Br counts as 1, so the coordination number is the combined number of CO and Br inside the brackets. Hope this helps!

Sarah Hernandez 1F

I don't know how to name this, it's asking for the systematic name, please help.

: E9CDFA8F-4459-4456-919A-D89BBAE5774A_4_5005_c.jpeg (12.82 KiB) Viewed 363 times

Sarah Hernandez 1F

Not too bad! All my classes are wrapping up and I only have two finals so I just need to keep working and soon it'll be winter break!

Sarah Hernandez 1F

It's going okay, I've been relying a lot on previous knowledge that I learned from AP chem and overall I'd say I'm not doing too bad, but I definitely need to work on my studying habits and spend more time preparing for the final than I did the midterm.

Sarah Hernandez 1F

The way I think of it is add the number of lone pairs and bonds on an atom and that number corresponds to the hybridization, on sapling there's a good table that puts them together like if the number you get is 4 then its sp3 which is helpful if you're not familiar with it yet.

Sarah Hernandez 1F

Besides doing the textbook problems, I've heard reading the textbook is super helpful because it goes really in-depth on the information so I'm going to be trying that

Sarah Hernandez 1F

Does anyone know if Dr. Lavelle is going to unlock the two previous midterms--so we can review the problems? I'm not sure, I think that as of right now the only way to see the previous midterm questions is going to office hours with your TA and even then they'll just read out the questions instead ...

Sarah Hernandez 1F

Hi! The best way I've found to start is to put all the carbons down with the bonds between them, and for this problem there are double bonds between all of the carbons, and then you can just add the hydrogens on the ends, and based on how many bonds carbon can form and the fact that the problem tell...

Sarah Hernandez 1F

I started with looking at a single carbon atom, since they all have the same bond structure, and then counting how many bonds it had connected to it. Then, I looked at the shape they made when branching off from the carbon atom. yeah like what Adalia said, because it asks for the geometry around ea...

Sarah Hernandez 1F

I mostly just stare at the vsepr sheet, trying to redraw the shapes or just memorizing the numbers helps like how many bonds and lone pairs are associated with the names and once you think you're familiar with them the sapling hw for this week has a lot of questions about naming the shapes so that's...

Sarah Hernandez 1F

I haven't heard of there being any but I agree that it would be nice

Sarah Hernandez 1F

I've been working out a couple times a week and going for walks.

Sarah Hernandez 1F

The first thing I like to do is take a nap/sleep. If that's not your style or if you're not tired taking the time to do something productive that is not school related is usually nice like finishing a book or baking/cooking food, it's always a great time to try out new recipes!

Sarah Hernandez 1F

Lewis acids are molecules that would accept electron and Lewis bases are electron donors so as an example molecules that have negative charges are likely Lewis bases

Sarah Hernandez 1F

Thanks everyone for your help, I get it now!

Sarah Hernandez 1F

Hi Amanda, firstly I'd say you need to think about the number of valence electrons of each of the atoms, like carbon has 4, as that helps determine how many bonds and lone pairs they would have. From there you should be able to determine the formal charges as the images show how many bonds/lone pair...

Sarah Hernandez 1F

Thanks Kaylee and Jason your explanations were really helpful!

Sarah Hernandez 1F

I got this question right but I was mostly guessing, could someone explain why d was the right answer?

Sarah Hernandez 1F

I got the other parts of this question right and I don't know why this one is wrong please help.

Sarah Hernandez 1F

If you have the ccle app on your phone, the fourth icon on the bottom will show you your grades for all your classes!

Sarah Hernandez 1F

I've found a lot of what we learned familiar, and I did take AP and honors chem in high school so I probably did learn a lot of it in AP. I can't remember if I learned about light in chem though and I know I did in AP physics so it might have been the combination of classes that are helping me now.

Sarah Hernandez 1F

Lucy Weaver 1F wrote:I've heard it will be more than 12 questions this time.

And to add to that each question will be worth less points than last time

Sarah Hernandez 1F

I'm doing alright, I still struggle a bit with managing my time but I get all my work done and for this class so far a lot of the material we've covered has been review from high school which is nice.

Sarah Hernandez 1F

I've heard from upperclassmen that it's not recommended to double up on science classes winter quarter of freshman year since it ends up being a lot of work, so if you can it might be better to look into GEs for your third/fourth class.

Sarah Hernandez 1F

No problem I'm glad my explanation helped!

Sarah Hernandez 1F

I think someone said he won't be posting more, I thought they were really helpful too but he does go over everything in the lectures too

Sarah Hernandez 1F

It might say on one of the outlines how much you need to know, but I think generally speaking that it's not necessary to remember all the exceptions, it would probably be helpful though.

Sarah Hernandez 1F

My favorite TV show is Leverage! It has five seasons and ended a few years ago but they've recently decided to start it up again with the original cast!

Sarah Hernandez 1F

Hi! So to find the amount of spectral lines I would consider where the electron begins, n=5, and what the lowest shell it can go to which would be n=1 and just subtract the second number from the first. To get the wavelength range, you would have to solve for the wavelength of the transition of n=5 ...

Sarah Hernandez 1F

Me and some of my friends went on zoom and played Among Us! Some of us had dressed up too so it was really fun!

Sarah Hernandez 1F

I've been going through the textbook problems listed in outline 1 and 2 and also checking off the bullets if I'm sure I know how to do them. I think that's a good way to make sure you have all the material covered but reviewing notes and doing the sapling problems would also be helpful. I'm not sure...

Sarah Hernandez 1F

I got this question wrong and I'm just not sure how to go about solving it, like what should I do with 1,650,763.73 wavelengths? The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted by krypton-86 (it has since been redefined). What is the wavelength of this krypton-86 radia...

Sarah Hernandez 1F

Hi! I don't think there's any difference, like you said E means the same thing as 10^ it just takes up less space on the calculator screen and requires less buttons being pressed as it's shorthand

Sarah Hernandez 1F

For empirical formulas, your coefficients should the smallest whole numbers possible, so if you notice while you're multiplying that all of the numbers you have are divisible by two make sure to divide everything by two and in some cases you'll just have big numbers with no common multiples so that'...

Sarah Hernandez 1F

My Ta said a scientific calculator is highly recommended but if you don't have one you can use a graphing calculator

Sarah Hernandez 1F

For me, taking notes while watching the lectures or other videos like the ones from the audio visual focus topics is really helpful. I think it forces me to pay attention and I can always pause or rewind which is nice because you can't do that during a live lecture. To make sure I don't fall behind ...

Sarah Hernandez 1F

Hi! So from what I understand, respondus will be used on whatever device you're taking the exam on, so you would need a separate webcam (I believe we will be able to use a phone or tablet as well) to be showing your workspace.

Sarah Hernandez 1F

So technically, this reply comment wouldn't count? I just want to verify, I don't accidentally want to miss easy points for the class. Thank you. I believe this comment would count as a point. You're still technically helping another student with questions regarding the class. What would be the due...

Sarah Hernandez 1F

Another thing to note is that you should not round to get sig figs until the final step of the problem when you get the solution.

Sarah Hernandez 1F

Planck's constant is the proportionality constant discovered by Max Planck which he derived after trying to figure out the relation between the frequency of a photon to its energy because at the time the existing theories were found to be not entirely accurate. You can look up more online if you wan...

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