CHEMISTRY COMMUNITY

Jamie Hwang 2F

is it even still happening? Because someone said that the UA step up sessions will probably be cancelled as they are going home

Jamie Hwang 2F

Test 2 grades are up are myucla but I doubt that we will get our actual tests back. I wish we knew more about what was happening.

Jamie Hwang 2F

I'm pretty sure we are not supposed to go to any classes but it says that in the email that "we will suspend in-person classes wherever possible" so it's kind of confusing what exactly protocol is.

Jamie Hwang 2F

I think that we will have to send pictures of our hw to our TA but I don't think anything is certain right now.

Jamie Hwang 2F

I really hope this is still happening some way and if it doesn't, that sucks because it's Lyndon's last one.

Jamie Hwang 2F

I'm sure that Lavelle will address everything in an email but we still haven't gotten an email which concerns me.

Jamie Hwang 2F

There is no official study guide but the UA's and some TA's set up some stuff to help us, like my TA has worksheets that we do and go over in discussion.

Jamie Hwang 2F

I think the equations sheet on Lavelle's website is the one we will get for the midterm and the final.

Jamie Hwang 2F

I always thought it was 5 per week before Sunday of that week is over but your TA may be lenient about that stuff. I guess it depends on your TA.

Jamie Hwang 2F

Yeah I was confused about that bc I caught some errors in the solutions manual that had to be mistakes but I didn't really see them addressed on Chem Community.

Jamie Hwang 2F

usually we get it the following week in our discussion sections.

Jamie Hwang 2F

I would just do hw problems for calculation-based problems and then read the textbook and Lavelle's notes for the conceptual stuff.

Jamie Hwang 2F

I would go with whatever the learning outcomes page says.

Jamie Hwang 2F

I think drop ins would be best for that but I'm sure all the UAs will be able to help if you ask.

Jamie Hwang 2F

Probably topics that are covered in test 2.

Jamie Hwang 2F

There are no extra credit opportunities for this class, sadly.

Jamie Hwang 2F

Test 2 was moved to week 9, starting Tuesday of that week.

Jamie Hwang 2F

I've heard of quite a few people doing that. I think it kind of depends on what other classes you are taking as well.

Jamie Hwang 2F

Personally, I am taking 14A-D first and then BL and CL just because A-D is more important/are requirements for other classes that I have to take. I think it depends on your schedule/plan.

Jamie Hwang 2F

I think HW based on topics covered on the midterm are good since we literally just started the new section but I guess it's based on what you think.

Jamie Hwang 2F

He is not adding any more material to Test 2, he just gave us more time to study for it.

Jamie Hwang 2F

Celena Kim 2I wrote:I believe you can sign up for tutoring through AAP.

I heard of that too and I kind of want to look into it more.

Jamie Hwang 2F

I just subtract from the number of posts from last quarter. I had exactly 50 last quarter so it is easy to figure out.

Jamie Hwang 2F

That is so helpful. I had no idea.

Jamie Hwang 2F

I think if you do a straight scale where 450/500 to 500/500 points is an A- to A+ and so on, then you could get some idea of your grade because I'm pretty sure if there is a curve it can only help and not hurt your grade.

Jamie Hwang 2F

I think every TA is assigned one problem that they grade for every test.

Jamie Hwang 2F

cancelling units when you solve the problem and keeping track of them is what I do to get the final units

Jamie Hwang 2F

He only does free response questions which I like because you can get partial points

Jamie Hwang 2F

for more info, Lavelle has a page on his website that says the topics and there are also topic outlines

Jamie Hwang 2F

there are no extra credit opportunities but i would talk to the TA

Jamie Hwang 2F

thank you!

Jamie Hwang 2F

All the info on the midterm and the review sessions is on his website under the midterm tab.

Jamie Hwang 2F

Everything is on his website. It can be a little hard to find but it should be there.

Jamie Hwang 2F

I don't think the final has an answer key uploaded. I'm not sure why only the midterm does but I'm sure that there is a reason.

Jamie Hwang 2F

I wish they were Bruincasted but they are not. The closest thing is the video module that he has on his website but it doesn't cover all the concepts.

Jamie Hwang 2F

The TAs don't take attendance during discussion but that's when you turn in HW and they go over practice problems or concepts so they're pretty helpful.

Jamie Hwang 2F

All of the partial pressures added together should result in the pressure.

Jamie Hwang 2F

I think all scientific calculators are fine.

Jamie Hwang 2F

For HW I just work on the problems from the unit that was discussed before my next discussion.

Jamie Hwang 2F

Partial credit is usually given, I guess it depends on the rubric.

Jamie Hwang 2F

Sometimes the tests, including midterm and final, will include stuff that was only mentioned in lecture so I would pay attention to what diagrams or specific examples were in the lecture notes as well.

Jamie Hwang 2F

Yeah, K is at equilibrium while Q is at any stage of the reaction.

Jamie Hwang 2F

I guess it also depends on when you have discussion which HW you do.

Jamie Hwang 2F

There is no study guide but I really recommend doing HW problems and going over the notes from lecture. Additionally, you could look at the video modules on his website and do the assessments that come with those cause they have more practice problems.

Jamie Hwang 2F

Test 1 covers all of chemical equilibrium and Acid and Bases.

Jamie Hwang 2F

Does anyone know if we can come in at any time to pick up our finals or will we be told when to pick them up in lecture?

Jamie Hwang 2F

The 5 questions just have to be on the list of problems in the syllabus. It can be any one of them but they should relate to what we are going over in class. Technically you don't need to do all the problems listed in the syllabus but I would recommend doing them all.

Jamie Hwang 2F

I think I heard somewhere that you have to pay for Sapling, is that true or is it free for anyone to use?

Jamie Hwang 2F

Can we pick up our finals any time during second week or will there be a specific day that we can get them?

Jamie Hwang 2F

RichBollini4G wrote:Does anyone know if the homework is graded for completion or for correctness?

It's really up to your TA. My TA grades for completeness because we have the right answers in the Solutions Manual but you should ask your TA if you're not sure.

Jamie Hwang 2F

We have to have at least 5 post every week before the week is over (I think by Sunday night) and at the end of the quarter we need to have at least 50 posts in all.

Jamie Hwang 2F

The final has to cover everything so I'm sure it will be on there but I don't know how important it will be point-wise. I would just think of every topic as important.

Jamie Hwang 2F

Lavelle has a list of ligand names on his website which are pretty important to know.

Jamie Hwang 2F

Spend your time carefully. I would spend more of my time on acids and bases than fundamentals and little stuff like that.

Jamie Hwang 2F

005162520 wrote:What are some examples of group one and group 1 and group 2 oxoacids?

Li2O and MgO are oxoacids.

Jamie Hwang 2F

Paige Lee 1D wrote:For #1c on mini marshmallow, how do you know to choose NH4+ and not NO3- for the net ionic equation? Since they're both weak acids and bases

NO3- is the conjugate base of HNO3 which is a strong acid.

Jamie Hwang 2F

KBELTRAMI_4I wrote:For number 4 how does the hybridization become sp2 if there are 4 p electrons and 2 s electrons?

Hybridization is determined by electron densities around the central atom. Since S has three electron densities the hybridization is sp2.

Jamie Hwang 2F

For number 41(c), it asks which pair of atoms on thymine are most tightly bounded and why, between C=C, C=O, and C=N. However, O don’t see a C=N bond in the structure. Is there a mistake? I think there is a mistake on that but it doesn't matter because the answer is C=O because O is the smallest ou...

Jamie Hwang 2F

Will the final have more questions about the content we learned after the midterm or will it be cover the entire quarter evenly?

Jamie Hwang 2F

Cis platinum is a chemotherapy drug used to stop cell division. I think we have to know its purpose and its structure for the final.

Jamie Hwang 2F

Clean coal has a lower sulfur content than dirty coal does.

Jamie Hwang 2F

I doubt that anything beyond the 1-14 scale will be tested on, so I wouldn't worry about that.

Jamie Hwang 2F

Will we get marked down if we use one version over the other?

Jamie Hwang 2F

I'm pretty sure this won't be on the test but I just wanted to make sure that we won't be tested on intermolecular repulsions. It was in the textbooks so I'm not 100% sure.

Jamie Hwang 2F

For this problem, the choice showing dipole-dipole interactions between the molecules has the strongest attraction. In choice II, the partial positive H are nearest to the partial negative Cl, giving these molecules the strongest intermolecular interaction. In addition, you know that different mole...

Jamie Hwang 2F

A molecule is polar if it has dipole moments so if the dipole moments cancel out then the molecule is nonpolar.

Jamie Hwang 2F

I don't think we have to "use" it in the sense that we will bee plugging in values because we never did that in lecture. I think we just need to know it conceptually so the smaller the distance, the greater the potential energy which means it's a stronger force. Stuff like that.

Jamie Hwang 2F

I think the bonds from lowest to highest strength is: induced dipole-induced dipole (london dispersion) < dipole-induced dipole < dipole-dipole < ion-dipole < hydrogen bond < covalent < polar. I got this list from a step up session but now I'm confused bc in a different workshop, the list was: induc...

Jamie Hwang 2F

What topics should we expect to show up on test #2? From what I've heard, Test 2 will cover material up until Friday's lecture. Based on this, questions on Test 2 can appear from any material up until VSEPR. This includes, but is not limited to: 1. Review of high school chemistry 2. Quantum 3. Chem...

Jamie Hwang 2F

Did Lavelle cover all of the different structures that we will need to know or will there be more on Friday's lecture? I think he will go over more on Friday just because he didn't go over the specific shapes that occur once lone pairs get involved and some of the HW problems ask for those structur...

Jamie Hwang 2F

I think there might be some confusion in the question. Question 2E.7 asks "b) How many different OSCl bond angles are there in this molecule? c) What values are expected for the OSCl and ClSCl bond angles?

So it's not asking about bond lengths.

Jamie Hwang 2F

A lone pair of electrons is similar to a bond of shared electrons as they are regions of electron density surrounding the central atom. So instead of being linear, the lone pair of electrons repels against the electrons that are bonded, pushing them away and resulting in an angular shape.

Jamie Hwang 2F

I'm pretty sure we will have to know those shapes just because we were assigned HW problems where some of the answers involved those shapes. Like other people mentioned, Professor Lavelle will probably go over them on Friday.

Jamie Hwang 2F

Will we ever be tested on the shapes of pentane and 2,2-Dimethylpropane that Dr. Lavelle went over in lecture? Specifically, do we have to know their shapes and how the atoms are arranged?

Jamie Hwang 2F

I wish he did post his slides especially since there are no more online modules for the rest of the concepts.

Jamie Hwang 2F

This is really far in advance but I was wondering what the process was like to be a UA. I've seen undergraduate assistants in a few of my classes and I think I might be interested in becoming one but I'm not sure how. Is it different depending on the class or is it all under the same program?

Jamie Hwang 2F

Does anyone know if the final will be cumulative of everything we have done this quarter or is it just stuff we learn after the midterm?

Jamie Hwang 2F

I'm kind of confused on what will be on the test. Will the test go over polarizability and dipole moments because that wasn't really on the midterm?

Jamie Hwang 2F

Hailey Kim 3B wrote:When is test 2?

Test 2 will be week 8 in your discussion section.

Jamie Hwang 2F

I don't think he has any more video modules. The last one was Heisenberg and we learned that a while ago.

Jamie Hwang 2F

It says on Monday and Tuesday (Nov 4 and 5) that there are review sessions for bonding/structures. There are 4 of them just for bonding/structures so does that mean they are all going to be the same or are they going to go over different stuff/different examples?

Jamie Hwang 2F

On the midterm review sessions page on the website, it says that on Monday, November 4, Professor Lavelle is going over past exam questions at 12-12:50 but that's when we have lecture. Does that mean that on Monday, we don't have lecture and it is going to be a review session? Can we go to other ses...

Jamie Hwang 2F

Is electronegativity and electron affinity the same thing?

Jamie Hwang 2F

https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/Midterm_Review_Sessions_14A.pdf

This is the link to the page with all the review sessions on the website.

Jamie Hwang 2F

quresh3E wrote:What does that mean when he said they were half shell and full shell?

Half shell means when all the orbitals in the subshell have one electron. Full shell means when all the orbitals in the subshell have two electrons. So 3d^5 would be half shell and 3d^10 would be full shell.

Jamie Hwang 2F

Is it because 4s is in a higher shell than 3d? Since 4s is in the shell further away from the nucleus than 3d, it would be removed first?

Jamie Hwang 2F

So if ml = 0 then the electron would be in the 2py state? And if ml = 1 then the electron would be in the 2pz state?

Jamie Hwang 2F

One of the exceptions deals with the d subshell. For example, if you followed the pattern, Chromium should look like [Ar]3d^4 4s^2, but Chromium is actually written as [Ar]3d^5 4s^1 based on experimental results. This is because when you are filling up the subshell for d, 4 orbitals have one electro...

Jamie Hwang 2F

Your values for l are correct but you don't have all the numbers for ml. ml = l, l-1, ..., -l. So basically for n=3, the values for ml would be -2, -1, 0, 1, and 2. You have to include the positive and negatives values for every number you stated for l.

Jamie Hwang 2F

If we have a full shell, what would the quantum number be? Do they cancel each other and it is zero (that doesn't really make sense) or is it just the last spin state (+ or - 1/2)?

Jamie Hwang 2F

I always used 3.0*10^8 in high school but it's probably better to use the values from the constants and equations paper that is on Professor Lavelle's website.

Jamie Hwang 2F

1 J = kg*(m/s)^2. It is really helpful to convert a joule to its base units so that when you are doing calculations, you can easily cross out units and see what your final answer should be.

Jamie Hwang 2F

In the solutions manual, the answer for this question has 5 sig figs and I was confused on how they got 5 sig figs (the given value in the question has 6 sig figs, and the constants used in this equation (like Planck's, speed of light, conversion from ev to J) have either 3 or 4. I don't know if we ...

Jamie Hwang 2F

In the solutions manual, the answer to 1A.11 mentions Paschen and Brackett series and I was just wondering if that was something important that we need to know because it wasn't really mentioned in the textbook.

Jamie Hwang 2F

From what I've heard, from my TA and Step-Up, we don't need to know how to name the more difficult compounds but we should know common/simple ones like salt and water.

Jamie Hwang 2F

I think Professor Lavelle mentioned that Quantum Mechanics will be covered in the next couple of weeks. At least I hope so because I've only been working on Fundamentals this week.

Jamie Hwang 2F

Are we really only allowed to use pen on the test? What happens if we make a mistake on the paper, can we get scratch paper or extra pieces of paper?

Jamie Hwang 2F

When I went to Drop-In, the UA said that you should study what Professor Lavelle discusses in class and the modules rather than reading the textbook. The UA said you should only be using the textbook to do the HW and not to actually learn the concepts. I was reading the textbook to study and I notic...

Jamie Hwang 2F

Will we have to know net ionic equations for the test? I heard that we only need to know the topics that Professor Lavelle goes over in lecture but a net ionic equation was on a HW problem M9 so I was just wondering.

Jamie Hwang 2F

When I'm working on HW outside I usually take out the section that I need from my loose leaf textbook and just leave the rest. It is really heavy especially if you have other stuff to carry so it's nice to pick and choose what you need. It might be a little messy though but if you're careful I think...

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