CHEMISTRY COMMUNITY

James Patanian 2C

Giselle_zamora_3E wrote:Yea same, I had like 7 more questions to go in like the last 15 mins, and I looked through them and I was so sad because they were problems i knew how to do but I just did not have the time

Same here, I could have finished it comfortably if I had more time.

James Patanian 2C

I'm glad I'm not the only one who felt rushed lol

James Patanian 2C

Lowkey I feel like people who had the constants saved on their calculators had the upper hand here. At least with the midterms there was enough time to finish regardless of that and still have a healthy time constraint. From my perspective, this was either an excessive time constraint or an excessiv...

James Patanian 2C

For real, the midterms were much more balanced between long and short problems, and I don't even think there were any conceptual problems on this final. And yeah, I definitely didn't feel confident in my answers either because I didn't have time to double check my calculations on the ones that I did...

James Patanian 2C

Did anyone else not finish the final exam? I had to guess on the last 6-7 questions, which will probably be terrible for my final grade. I wish we had more time since a lot of the questions involved long calculations, Lewis structures, etc. that took longer for me than 3 minutes per question. I hope...

James Patanian 2C

Chem_Mod wrote:Certainly know the acids and bases I covered in class.

Hi, should we memorize the ones discussed in lecture or understand the full methodology to naming them?

James Patanian 2C

At the most maybe we'd need to look at the visual representation of the s, p, d orbitals and describe where the electron density, or lack thereof is. I don't see how it could be worded as a problem though.

James Patanian 2C

I agree with the previous answer and would just like to add that seeing a carboxyl group indicates that it's a weak acid, not a strong one, so that's definitely something to keep in mind. However, the COOH carboxyl group is stronger than a molecule with just an -OH group because the increased oxyge...

James Patanian 2C

It's working for me right now, is it still not letting you play it?

James Patanian 2C

Yeah, the problem asked to identify the possible geometries so I don't think we need to be able to definitively determine which among them is the most accurate one yet.

James Patanian 2C

Mahnoor_Wani_2F wrote:There is a lot of pre-made quizlets available that you can use as flashcard to study or as a practice test. I recommend this method because you can use quizlet on any browser anywhere

Thank you that's a great tip!

James Patanian 2C

Honestly I'm still working on this, as I've realized my study methods in high school weren't the best for long-term understanding, but recently I've been trying to do more of the textbook problems since I have more difficulty with application problems rather than conceptual ones. It's been hard but...

James Patanian 2C

I've heard this with the math departments, but sometimes professors can lower the threshold for overall grades in the class if they choose to. But, as of now, the standard gradescale applies to 14A.

James Patanian 2C

I like what everyone is saying and when it comes to cramming at the last minute, cramming material does more harm than good but I've found that going over the format of the test before it starts can be pretty therapeutic. In this case though, we know that it's going to be x amount of multiple choice...

James Patanian 2C

Yes they seem pretty short so I think that we'll get to them. Plus he has mentioned that we'll make it to acids and bases in lectures.

James Patanian 2C

For the expanded valence shell, does this then mean that the maximum expanded valence shell is 10 or 12 (or more, if the atom has a negative charge)? I'm a little confused since the normal valence is 2 in s and 6 in p, but 12+ seems like a lot in the outer shell. I think the most normal examples ar...

James Patanian 2C

Jack Kettering 2H wrote:Hopefully sometime later this week but its possible the scores will be delayed due to the thanksgiving holiday but I hope not :)

Yeah last time I think it only took till like Wednesday of the next week

James Patanian 2C

105618850 wrote:Yes, molecular shape often displays polarity. Differences in dipole moments result in an asymmetrical structure/unequal bond lengths.

With how frequently bond lengths can change, is it fair to say bond lengths that we know of are not ever really concrete measures but more so rough estimates?

James Patanian 2C

Jalyn Davis 3J wrote:Does anyone know if discussions are cancelled for this week?

Why do you think they’d be is something going on?

James Patanian 2C

Yeah I had trouble navigating and figuring out logistics too but his class website gives some clarity to stuff that’s confusing. Also, the link to the pdf is with UA sessions is on the class website.

James Patanian 2C

Mikayla Kwok 3L wrote:4s does have a lower energy than 3d when no electrons are in the 3d subshell, but once the 4s and 3d subshells are occupied (which happens after Z=20), 3d has the lower energy.

Would that be the case because 3d fills out first so once 4s fills out too it is higher energy?

James Patanian 2C

Another thing is when drawing the structure of a compound, the most electronegative atom(s) (or highest ionization energy) is the one in the middle of the other atoms.

James Patanian 2C

LuveiaPangilinan 2C wrote:remember that in the periodic table, anything past the 2nd row is allowed to break the octet rule and does not need to obey it. However, Rows 1 and 2 have to.

Wait but isn’t boron one of the exceptions since it will usually have less than an octet and is in the second row?

James Patanian 2C

haileyk wrote:Hi!

The midterm will cover the last 8 bullets of outline 2 as well as all of outline 3.

Yeah, my TA said it would be all of outline 3.

James Patanian 2C

I'm not sure if we would be given those but an easy way remember them though is by looking at the what group the atom is in.Group 1 has a +1, Group 2 has a +2, Group 13 has a +3, Group 14 has +-4, Group 15 has -3, Group 16 has -2 and group 17 has -1. These are determined from the valence electrons ...

James Patanian 2C

Heather Szeszulski 1I wrote:Any serial killer show but the best of all time is NCIS.

Oooo good looks I'm gonna check that one out but I don't know if it can top Dexter

James Patanian 2C

Based on what we've learned, I think the actual values aren't as important as what they are assigned to. I think the values are associated with the different orientations of each of the orbitals. For example, the p sub level has three orbitals of px, py, and pz, each being associated with -1,0, and...

James Patanian 2C

I understand that the number of numbers in the Magnetic Quantum Number corresponds to the amount of orbitals (1 for s, 3 for p, 5 for d, 7 for f). Why is it represented the way it is though? Why is -2, -1, 0, 1, 2 used to represent that msubl corresponds to the p sublevel with 5 orbitals? I see that...

James Patanian 2C

Brian_Wu_3G wrote:From this wikipedia article, https://en.wikipedia.org/wiki/Quadruple_bond, There seems to be a quadruple bond between Re - Re. It states that quadruple bonds usually form with d-block elements.

Sorry for the late response but thanks Brian, that answers my question :)

James Patanian 2C

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StephanieIb wrote:The fourth bond in a quadruple bond is a delta bond. Carbon doesn't have any d electrons to form a delta bond. So carbon can never form quadruple bonds.

So an atom would need a valence in the d orbital to form a delta/quadruple bond? Are these observed in nature frequently?

James Patanian 2C

I answered the question conceptually by thinking about how the number of photons is another way of saying the amplitude, and amplitude affects intensity, not wavelength or frequency.

James Patanian 2C

C is the speed of light in a vacuum and for practical purposes for doing calculations in 14a, I’m assuming we will say that it is the speed of light in any case.

James Patanian 2C

To add, the Rydberg equation would be useful when aiming to solve for frequency rather than energy. Although, you can use either equation and Dr. Lavelle prefers the empirical.

James Patanian 2C

What is the difference between putting *2nd* and *comma* to get E and putting the number 10 on a calculator? I know that when getting 10 to a power, the calculator displays it as E^power, with E being equivalent to 10. But, why would it make a difference when inputting something with 10 as the base ...

James Patanian 2C

In SI units, the real gas constant, R, is equal to 8.3145 Joules/mol K. However, if we express R in units of L atm/mol K, it's value is 0.08206. It's just a case of unit conversion. If we are calculating using the ideal gas equation PV=nRT then we use the .08206 because we will we will be calculati...

James Patanian 2C

In case you need the formula sheet or periodic table: https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/Periodic_Table_IUPAC.pdf https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/constants_equations.pdf Oh thanks Alvin! So do we know that these are the two resources ...

James Patanian 2C

Have you seen an example where it isn’t specified? I’m not sure what that’d be like either.

James Patanian 2C

Thanks Faith :)

And if he doesn’t clarify I’ll just ask my TA before the midterm starts.

James Patanian 2C

Does anyone know if we can use Dr. Lavelle's laminated formula sheet (the one on Amazon for $10) on the midterm? I know we'll get a digital or physical formula sheet for the midterm but I'd like to know if I'd be able to use that one.

James Patanian 2C

Hi, do we need to know how to round sig. figs when dealing with logarithms for the midterm? Will we be dealing with logarithms much at all in this level of chemistry?

James Patanian 2C

Is the reason why we would usually move over the base three decimal places and have the 10 raised to degrees in increments of three because the metric system is multiplying or dividing by 1000 to go from one to the next unit?

James Patanian 2C

Thanks guys. I think it might just be called the molecular formula if they are equivalent tbh but I don't think that will be very important to know considering that he hasn't mentioned it. Also, is the only reason of having the empirical formula to find the molecular formula or is there something el...

James Patanian 2C

What do you call it when the empirical and molecular formulas are one in the same?

James Patanian 2C

For exams, we are going to have Zoom open showing our face. We are going to have respondus open showing our webcam. We are also going to have the midterm open on our computer. Are we supposed to have all three of these things open on our computer? Can we have respondus separately on our smartphone? ...

James Patanian 2C

Someone in my disc. section said there is a place on Dr. Lavelle's website that has the full range on a formula-type sheet that we could print out and have with us. Does anyone know where to find that on the website because I haven't been able to?

James Patanian 2C

To add on to that question, will it be fully multiple choice? Will it still be 50 minutes and closed-book as stated on the syllabus? What does closed-book entail?

James Patanian 2C

Ok bet thanks guys :)

James Patanian 2C

Just to be clear, once we correctly answer the 10th question on the Sapling homework has it automatically submitted the homework? I don't see any submit button otherwise but I think there was a confirmation screen after the 10th question that I accidentally skipped past without reading.

James Patanian 2C

Are there a lot of topics in the book that are not covered during lecture that show up on tests? I don’t think so. Anything not mentioned in lecture or on assigned hw shouldn’t be on tests. However, the additional learning and reviewing that Dr. Lavelle emphasizes are probably essential to understa...

James Patanian 2C

Yes! Thank you so much. I really don't understand how we were expected to know how to operate this website without a basic walkthrough or something but I'm thankful that you were able to explain to me :)

James Patanian 2C

On my screen it only says "Post Reply" in red and I don't see "New Post." This is so weird.

James Patanian 2C

Thank you Ariel, and I will attend his office hours for the other questions. Where does it say "New Topic" though in the top left? I only see Quick Links, Board Index, social media links in the top left area. I'm sorry if this sounds silly I just genuinely don't understand.

James Patanian 2C

Also sorry I forgot to add this but is the class fully asynchronous now by watching the prerecorded lectures?

James Patanian 2C

Guys, I have no idea how to post on this forum or contact anyone in the class but I hope Dr. Lavelle will explain it soon. I have a few questions though that maybe someone can answer: Is the code for the $72 ebook for the class from the UCLA website going to be emailed or physically mailed to my hou...

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