CHEMISTRY COMMUNITY

David He

NayeliPlayas_2J wrote:In an email he clarified that the final would be the same format as the past 2 midterms; all the questions are going to be multiple choice. Good luck on the final!

Good luck to you too!

David He

Brenda Silva 2L wrote:The final would be similar to the last two midterms, all questions would be multiple choice.

Cool!

David He

Katie Lam 2G wrote:All questions are multiple choice, and there is no partial credit this time :(

I'm missing partial credit :(

David He

Charisma Arreola 2L wrote:Yes, it will be almost exactly like our past midterms!

Great!

David He

Jonathan3L wrote:He said it will be the same format as the previous mid-terms so I take it that it will be multiple choice only.

Got it

David He

Eunice_Castro_1G wrote:Hi! All of the questions will be multiple choice. Hope this helps!

It does help, thank you Eunice!

David He

Irene Nguyen 3H wrote:The entire final is multiple choice!

Thank you Irene!

David He

Margaret Wang 2A wrote:If you have two double bonds and a single bond on a nitrogen, the nitrogen would then have 10 electrons. Nitrogen cannot have more than 8 electrons in its valence shell. Only Period 3 elements and down can do that.

That helps a lot, thanks!

David He

While having two N=O bonds would make it more "stable" due to the lower formal charges, Nitrogen is only in period 2 of the periodic table, which means it cannot hold more than an octet. A structure with 2 N=O bonds and 1 N-O bond would mean that N is sharing 10 electrons, exceeding the o...

David He

At this point I also want to say thank you to all TAs in this class, thank you all for providing more than 100 hours of study opportunity in each week !

David He

Valerie Tran 2I wrote:He says on his website that the final is the same format as the midterms so its probably safe to assume there are only multiple choice

Got it, thanks Valarie!

David He

Jalyn Davis 3J wrote:Yes, all questions are multiple choice, like the midterms.

Got it, thanks Jalyn!

David He

Shalyn Kelly 1L wrote:Yep! As stated above, all questions should be multiple-choice, for 6 points each, with no partial credit. It'll be structured like the midterms. Good luck!

thanks shalyn!

David He

Katie Lam 2G wrote:All questions are multiple choice, and there is no partial credit this time :(

thank you katie!

David He

In the end of this quarter I want to say thank you to Dr. Lavelle again. Thanks for all your dedications in making chemistry such a great subject to learn

David He

Or we are expected to write down numbers, chemical names, and draw graphs as well?

David He

Hi, I met this problem for many times. Sometimes it's just UCLA VPN is not working so you need to wait. Other times maybe you need to change your wifi into cellular, or change chrome into safari or vice versa.

David He

When drawing nitrate ion, I assume the Lewis structure with two O=N and one O-N is more stable than a structure with one O=N and two O-N, but only the latter one is assessed as correct. Why is that?

David He

Chem_Mod wrote:On my class website:

Constants and Equations https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf

Periodic Table https://lavelle.chem.ucla.edu/wp-conten ... _IUPAC.pdf

Thank you！！

David He

Just want to know, where can we find the periodic table and equation sheet for midterm 2?

David He

That is correct

David He

Lewis acid takes electron and Lewis base provides electron

David He

In the sampling question you can click "hint" on the top then you will get a link to explanation!

David He

I recommend you just google the formula of the element. I don't think we are required to infer structure by its name

David He

In short, it's better not to leave lone pair in the central atom because it will imply unstableness

David He

I am still having trouble understanding the difference between the terms "ample" and "overwhelmingly" bond character. I know that real structures are a blend of resonance structures, but I am unsure about how to connect this idea to the bond character. Any kind of clarification ...

David He

I suppose the exam will be multiple choice only, so you will not actually draw the structure.

David He

Great video! I really appreciate that.

David He

bonding angle is determined by the number of atoms in a molecule and the arrangement of atoms

David He

There should not be any rigid rules for drawing atoms, because in reality, the site of atoms in a molecule can change slightly.

David He

First, we should know that lone pair makes an atom bigger, because electrons repel each other. If one pair of electron forms bonding, that means the electrons are attracted by other electrons, so they would no longer repel each other, making the size smaller. If you apply this idea, you will notice ...

David He

Bonding pairs are attracted by two nuclei, which stabilizes the repelsion force.

David He

First, we should know that lone pair makes an atom bigger, because electrons repel each other. If one pair of electron forms bonding, that means the electrons are attracted by other electrons, so they would no longer repel each other, making the size smaller. If you apply this idea, you will notice ...

David He

Hi, it confuses me too. Can anyone tell me how to determine the electronegativity of atoms?

David He

What is bond order? when did we learn that?

David He

I have purchased sampling access for 60 dollars or so, I believe that would be enough

David He

You can scroll down to the bottom of the topic that you have replied, and there it is!

David He

When will the score released, and where can we see them?

David He

Just want to be sure, do we have to post five posts each week, or it would be fine as long as we have 50 posts at the end of the quarter?

David He

Hi, I have made a schedule about when and for how long I should study each subject; it does help me to keep on track. Good luck to you!

David He

Should we be able to answer this question already? If so does anyone know the steps to solve it? Any help would be great. Thanks! What is the minimum uncertainty in an electron's velocity (Δvmin) if the position is known within 15 Å. What is the minimum uncertainty in a helium atom's velocity (Δvmi...

David He

Congratulations!!!

David He

5 in China

David He

Great question. I did not realize we need a webcam until I see this post. Sadly I don't know where to by a reasonably cheap webcam, but maybe I can sponsor you for $10 if you really like that $35 cam.

David He

Hi, I don't know the equation of the compound either, but I was able to do the question, so I suppose knowing the exact equation of the compound is not necessary.

David He

It should be positive, because 2.917 * 100 = 291,7

David He

Hi, I think you are right. We don't do rounding during the calculation process; we only round the number when giving the result

David He

Thank you Dr. Lavelle for always doing your best to make chemistry fun. I'm glad I had the privilege to take your class. We appreciate all your hard work and thank you for everything you've provided us with throughout this quarter.

David He

5 in China

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