CHEMISTRY COMMUNITY

alexandralopez 3F

I prefer to do write everything down. When i type things, its really hard for me to retain information plus personally i feel like having notebooks is easier to keep track of and look through

alexandralopez 3F

How many chem community posts should we have by Friday?

alexandralopez 3F

yes, im pretty sure you can use any calculator!

alexandralopez 3F

I try and schedule a list of things to do for the whole week at the beginning of the week in order to keep myself spread out over the week in order to avoid burnout

alexandralopez 3F · Re: Final Exam Time it is 9:30 am to 11am !!!

it is 9:30 am to 11am !!!

alexandralopez 3F

I try and give myself at least an hour before the exam to just relax and not focus on chemistry which can help me a lot when it comes to overthinking the exam

alexandralopez 3F

The final was a lot harder than the midterms last quarter!

alexandralopez 3F

50% of the points are needed to pass (C-)

alexandralopez 3F

Im planning on just spending time with my friends and relaxing!

alexandralopez 3F

Definitely Ami, if you like sushi!

alexandralopez 3F

How I met your mother is my all-time favorite! Definitely recommend.

alexandralopez 3F

I am part of Flying Sams! Love this org and everything it dedicates itself to!

alexandralopez 3F

Yes! You can post more but will not get extra points. Although my TA said that lavelle does take it into account if you go above and beyond in your posts.

alexandralopez 3F

Yes it is being reduced to help oxidize another element

alexandralopez 3F

Right now my favorite food is oatmeal cookies haha

alexandralopez 3F

Hey guys! I was wondering if anyone knew how many posts we should be at by this week?

alexandralopez 3F

what a fun way to unload before finals!

alexandralopez 3F

For me I find it really helpful to have a list of equations we are using handy while doing the textbook problems and after a while I get comfortable using them!

alexandralopez 3F

You can review them with your TA!

alexandralopez 3F

50% of the possible would be a C-

alexandralopez 3F

oatmeal cookies!

alexandralopez 3F

Only a couple more weeks until Spring break! Good luck prepping for finals everyone!

alexandralopez 3F

Hi! the explanation someone else gave was really good so ill just attach my work, in case its useful to reference as you are going through the problem! Hope this helps!

alexandralopez 3F

Hi! Entropy increases with the # of microstates, or in other words it increases as the phases become more mobile. So entropy would be positive when going from a solid to a liquid, liquid to gas, and solid to gas and it is negative when the phases become less mobile-- liquid to solid, gas to solid, a...

alexandralopez 3F

HI! I think it just depends on what the end units are. I think they give us both kJ and J just so we are more aware of what conversion are necessary in order to solve the problems.

alexandralopez 3F

Hi! When doing this problem its important to keep in mind that ΔG=ΔH−TΔS. When ΔH is negative and ΔS is positive, a postive number is being subtracted from a negative number, so ΔG will always be negative, regardless of the temperature(think leave it, change it, change it) . This means that the reac...

alexandralopez 3F

Hi, heres my work for this question! hope this helps!

alexandralopez 3F

Hey guys! Im having some trouble with number 18 on the hw. Calculate the equilibrium constant, K , at 25.0°C for each of the reactions. Use the thermodynamic information provided in the table. The hydrogenation of acetylene to ethane. C2H2(g)+2H2(g)↽−−⇀C2H6(g) So far I've calculated the Gibbs Free e...

alexandralopez 3F

For me, going through the outlines is what I find the most helpful for this class

alexandralopez 3F

For me, going through the outlines is what I find the most helpful for this class

alexandralopez 3F

HI! you should pick the R value that has the correct units necessary to solve the problem!

alexandralopez 3F

Yes thats right! But, the energy released from forming bonds is much larger than the energy needed to break the bonds which is what makes it exothermic

alexandralopez 3F

Yes! for this question I just drew out the molecules in order to determine whether it was linear or not

alexandralopez 3F

A negative sign means the system is doing work on its surroundings, so the more negative the value the more work is happening.

alexandralopez 3F

Hi! I totally understand how you feel. It can be really easy to get overwhelmed sometimes. What I find that really helps me is making a list of assignments/things I have to do for each class at the beginning of the week, along with deadlines. It really helps me keep track of everything I have to do ...

alexandralopez 3F

No, they cannot be negative!

alexandralopez 3F

the midterm is 50 min, but im not sure how many questions there will be.

alexandralopez 3F

yes they are allowed!

alexandralopez 3F

I felt like there was enough time to complete the problems and maybe look back on one or two that you were unsure of

alexandralopez 3F

Yes, im pretty sure it is the same

alexandralopez 3F

Going through the textbook problems and going to UA sessions are really helpful

alexandralopez 3F

Yes, they will be during your lecture times

alexandralopez 3F

They will be during lecture times!

alexandralopez 3F

Hey guys! Im having trouble getting the right answer for this question: Consider the reaction at 500°C .N2(g)+3H2(g)↽−−⇀2NH3(g). Kc=0.061 If analysis shows that the composition of the reaction mixture at 500°C is 0.716 mol⋅ L−1N2 , 3.47 mol⋅ L−1H2 , and 5.71 mol⋅ L−1NH3 , what is the value of the re...

alexandralopez 3F

Hey guys! Im having trouble getting the correct answer for this problem. Im going through the steps correctly but I think I'm making a mistake somewhere along the way. Can someone look over it pls? Thanks!

alexandralopez 3F

Hey guys! Im having some trouble with this problem, I think I'm probably just overthinking it but I'm not sure what to do after the ICE box. Could someone walk me through it? Thank you!!

If the Ka of a monoprotic weak acid is 2.6×10−6, what is the pH of a 0.17 M solution of this acid?

alexandralopez 3F

You only use Kp for gases/calculating partial pressure

alexandralopez 3F

I want to get outdoors more and focus on my mental health

alexandralopez 3F

Yea the exams will now be during lecture times

alexandralopez 3F

The concentration cannot be negative so you will use the positive one.

alexandralopez 3F

Hi guys! Can someone clarify the difference between equilibrium mixture and equilibrium concentration?

alexandralopez 3F

They will be up on saturday!

alexandralopez 3F

I felt like the timing for me was really off for the final but i think that was due to struggling a lot more with the questions on the final, which caused me to spend more time on the individual questions. Maybe a good solution would be to tackle the harder problems first but also give yourself a ce...

alexandralopez 3F

im pretty sure its just 50% of the total points

alexandralopez 3F

definitely going to try and go on hikes, be active, and binge watch a few shows

alexandralopez 3F

I think grades should be out Sat!

alexandralopez 3F

i dont think that would be accurate. I would say just look at the geometry of the molecule

alexandralopez 3F

This is because silver is more stable this way, with the d-orbital fully occcupied

alexandralopez 3F

(en) is just the abreviation of ethylenediamine and it is a ligand

alexandralopez 3F

Hey guys! I was looking at the breakdown of the points on the syllabus to see what I might need to aim for on the final in order to pass the course and i saw that it mentioned that a 50% is required to pass with a C- or higher. Does anyone know if this is referring to 50% of the total 500 points is ...

alexandralopez 3F

Definitely feeling a little stressed and overwhelmed as of right now

alexandralopez 3F

The arrows represent a dipole moment and they point towards the more electronegative element

alexandralopez 3F

Yes, youre thinking is correct! it is 3 sig figs

alexandralopez 3F

You have to take into account the shape and see what the pull is like (if the dipoles cancel)

alexandralopez 3F

I would follow green because i dont trust them

alexandralopez 3F

I dont think we know yet :/ maybe you can ask your TA?

alexandralopez 3F

I usually give myself a couple of hours to just do nothing and it really helps when i feel really burnt out. Going on drives, or walks can be really destressing too!

alexandralopez 3F

Yes they are in all molecules and they are the weakest

alexandralopez 3F

Yes they all follow the same trend

alexandralopez 3F

it is cummulative :) but i feel like there may be more of a focus on these last 3 weeks

alexandralopez 3F

I like to just focus and see how far apart they are on the periodic table, so the farther they're apart, the less covalent but you could also translate that into looking at the diff in electronegativity

alexandralopez 3F

I would check in with your TA but I feel like as long as you have the total 50 by the end of the quarter you should be good

alexandralopez 3F

I would def follow green

alexandralopez 3F

Can someone explain why london dispersion forces are the weakest bond?

alexandralopez 3F

yes they are counted aftert the decimal

alexandralopez 3F

For those of us that didnt do super well on the first midterm, what are you guys doing to try and better your study habits/preparing for the following midterm?

alexandralopez 3F

Ive just been focusing on the directions and trying to memorize those. Quizzing yourself on the trends would probably be really helpful!

alexandralopez 3F

Reign is one of my fav tv shows! You should check it out :)

alexandralopez 3F

Im taking both right now and personally Im doing a lot better in bio than I am in chem. I think its doable if you know how to manage your time efficiently

alexandralopez 3F

Can someone explain why when were doing electron configurations when we get to the D block we have to count one back. Like for example even though its in the fourth row we put a 3.

alexandralopez 3F

Daniela Santana 3D wrote:Do we have to do anything with the 25 degree celsius part of the problem to solve or is it something that is not relevant to the problem's solution?

I don't believe its relevant to the solution

alexandralopez 3F

Hey guys! I was wondering what were some of the most effective methods of studying you guys had in prepping for the midterm we just took and found to really help in terms of being confident about taking the exam.
thanks!

alexandralopez 3F

That part does not count when considering sig figs

alexandralopez 3F

HI! i think your best bet is asking your TA! i haven't heard much about how the grading is going to be tho :/

alexandralopez 3F

Hi guys! I'm reviewing the dilution problems from the textbook to prep for the midterm and I'm stumped on what to do for G5: A student prepared a solution of sodium carbonate by adding 2.111 g of the solid to a 250.0-mL volumetric flask and adding water to the mark. Some of this solution was transfe...

alexandralopez 3F

Ive been going off of the outlines he provides for every week! Theyre posted on the chem community website and they're the ones that have all the textbook problems he wants us to do so I suggest looking at those!

alexandralopez 3F

Ive been working on these problems too and Ive just been rounding to the nearest whole number if the integer is close enough and its been working for me so far and I've been getting the same answers as the ones provided in the answer key to the textbook.

alexandralopez 3F

Doing the textbook problems have been super helpful for me, because you get to actually apply the concepts we're learning. I usually do them after lecture and just do the sections that correspond from the lecture so I have a basic understanding of what I'm doing and I find it really helpful!

alexandralopez 3F

Ive been doing all the textbook problems! My friends who have taken 14a with lavelle in the past all say they are incredibly helpful in prepping for the midterm!

alexandralopez 3F

I would probably go off of the equations sheet Lavelle wants us to use! Its on ccle if you still need it!

alexandralopez 3F

Hi, i dont think we need to know black body radiation since the prof mentioned it wasn't really a chem topic in lecture and wasn't going to discuss it

alexandralopez 3F

I think if you want to be safe you should use the regular notation but honestly i feel like it should be fine! you can also always just ask your TA just to double check of you're more comfortable using the other notation.

alexandralopez 3F

yes! my email is alopez01@ucla.edu

alexandralopez 3F

jia207 wrote:Does anyone know if it will be multiple choice or short answer? Or would that be a good question to ask my TA?

My TA said it was multiple choice last week during section!

alexandralopez 3F

Yea im pretty sure we use it just to make the calculations simpler!

alexandralopez 3F

HI! I dont think you have to do actually do any of them but my friend who took chem 14a a couple quarters ago said they were really good problems to do especially to look over/practice before the midterms! plus i think they're just good practice to kind of navigate how confident you feel about the t...

alexandralopez 3F

i agree with everybody else who replied. Your best bet is storing the numbers and rounding only until you have your final answer.

good luck!

alexandralopez 3F

Hi!
When i was reviewing balancing chemical equations, I found this video from khan academy to be really helpful :) Hope it helps!

https://www.khanacademy.org/science/ap- ... troduction

alexandralopez 3F

Hi guys! Im having trouble with #7 on the hw for this week: A solution of CaCl2 in water forms a mixture that is 32.5% calcium chloride by mass. If the total mass of the mixture is 590.1 g, what masses of CaCl2 and water were used? Can someone explain how they approach a problem like this/what would...

alexandralopez 3F

Hi guys! I was doing question #4 on the homework and got a little confused on the sig figs.

Would someone mind explaining why 950000 only has 2 sig figs compared 80060 having 4 sig figs.

Initially I thought 950000 and 80060 would both only have 3 sig figs

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