CHEMISTRY COMMUNITY

LaurenChoi_1J

I know it was really hard for everyone to stay motivated this quarter! Relax during winter break and come back with a fresh mindset for winter quarter! Remember to always do your best but not to stress yourself too much over it! I find that giving yourself breaks when you feel like your engine is ru...

LaurenChoi_1J

Q: What’s a sign of a bad chemistry joke?
A: No Reaction

LaurenChoi_1J

Academic - to always push myself to do my best but not to stress myself too much over it!
Personal- eat healthier and exercise more haha

LaurenChoi_1J

Yes! Thank you Dr.Lavelle, TA’s, and UA’s! Thank you for taking time out of your today to always make sure we succeed and helping those who are struggling! I really appreciate Dr. Lavelle providing so many resources and caring so much about his students! It’s truly amazing to see!

LaurenChoi_1J

Grades will be posted by Saturday so I think we just need to wait until then, or you can just estimate what you got on the final, add up the points you earned and divide it by total points possible :)

LaurenChoi_1J

Probably just going to stay home and binge-watch a lot of shows haha! Pretty boring plans but it’ll be nice to just relax and take my mind off of school for a little bit!

LaurenChoi_1J

There is an alternative time for international students to take the final. If you go onto ccle and click on the finals tab, there's an opt-in option for international students.

LaurenChoi_1J

Lavelle will be going over past exam questions during his discussion sections so definitely attend his review sessions this week!

LaurenChoi_1J

I'm going to do textbook problems and definitely go to a lot of the review sessions!!

LaurenChoi_1J

What did all the other elements say to hydrogen?
What a loner!

LaurenChoi_1J

What's your reaction when you find out oxygen and magnesium are dating?
OMg!!

LaurenChoi_1J

If H2O is the formula for water, then what is the formula for ice?
H2O cubed!

LaurenChoi_1J

Want to hear a joke about nitrogen oxide?
NO!

LaurenChoi_1J

Thank you for asking! I'm a little stressed and anxious about finals, but other than that, I'm doing great and trying my best to get into the holiday spirit despite the circumstances this year!

LaurenChoi_1J

I know that a 50% is a passing grade because he mentioned this on the syllabus. I hope Lavelle curves the grades or at least gives us a little grade boost haha. I believe he will adjust grades accordingly at the end of the quarter after all the finals are graded and he gets a better sense of what ev...

LaurenChoi_1J

You can set up a time to meet with your TA and go over your exam to see what mistakes you made!

LaurenChoi_1J

I didn't do too well on the second midterm so my confidence is a little shaken, and I'm nervous about the new material that we are learning. Hopefully I do well on the final!

LaurenChoi_1J

Jalyn 3A wrote:When are we supposed to take the final? Is the final open for 24 hours or is it only open during a specific time window?

I believe it is only open during a specific time window. The final is on December 13th from 11:30 am to 2:30 pm (At least that's what is says on the ucla page).

LaurenChoi_1J

I believe we'll have more time on the final than we had for the midterms and it will be more questions since it's covering everything we've learned throughout the quarter. I believe the format will still be multiple choice!

LaurenChoi_1J

I will be attending UA sessions and doing textbook problems to study for the final!

LaurenChoi_1J

Don’t worry! I know this is easier said than done, but worrying and stressing about the grade will only bring you down! Bring your chin up and try to focus on how to move forward because there will be other opportunities to bring your grade up and try to remember, one grade doesn’t define you! Go on...

LaurenChoi_1J

I think watching Netflix after midterms is a great way to de-stress! A couple of my favorite are Gilmore Girls, Friends, The Office, and Parks and Rec!

LaurenChoi_1J

I believe this is possible if some parts of the molecule have polar regions and other parts have non-polar regions. Molecules that have polar and non-polar characteristics are amphipathic.

LaurenChoi_1J

Probably by sometime next week! Since there are no partial points on this exam, it should be easier to grade!

LaurenChoi_1J

Treat yourself, you deserve it!! Take a bath, go on a walk, take a nap, eat some good food, and binge some Netflix to help you desired and take your mind of things!

LaurenChoi_1J

What is the difference between dipole-induced dipole and dipole-dipole?

LaurenChoi_1J

I have the same question! I wasn't sure what this learning objective was referring to.

LaurenChoi_1J

can anyone give a general definition of what ionic character is? And how exactly do you rank them?

LaurenChoi_1J

Can anyone give a general definition of what polarizing power and polarizability is? And how you rank them?

LaurenChoi_1J

the magnetic quantum numbers range from -l to l. So if l was 1, the magnetic quantum numbers would range from -1 to 1 (-1,0,1).

LaurenChoi_1J

I believe one exception he talked about was boron, where it has the ability to only have 6 electrons and not fulfill the octet rule.

LaurenChoi_1J

I believe there are, but we do not need to know any of them past the f subshell!

LaurenChoi_1J

Yes! There's also a bunch of images online that have periodic tables labeled with the valence electrons that can be really helpful to add to your notes!

LaurenChoi_1J

I believe Lewis bases give electrons and Lewis acids accept electrons!

LaurenChoi_1J

I believe doing textbook problems are very helpful! And there are many helpful resources such as step-up sessions and workshops you can attend to get any clarification you need on topics you are struggling with!

LaurenChoi_1J

I have the same question as the op! Thanks in advance!

LaurenChoi_1J

I believe negative ions have a higher atomic radius because they have more electrons, but someone please correct me if I am wrong!

LaurenChoi_1J

In simplest terms, I believe it means that the inner electrons sort of act as a barrier so that the outer electrons don’t feel the pull of the nucleus as much.

LaurenChoi_1J

Can anyone describe what electron affinity is? Thank you!

LaurenChoi_1J

I believe the 3s orbital shields the 3p orbital, but I could be wrong! Anyone else feel free to give their input!

LaurenChoi_1J

Kaylee Nezwek_2G wrote:Ah I didn't realize it was the same for all electrons, thank you!!

No problem! Oh and in my reply I meant 9.1*10^-31, not 9.2*10^-31, my bad!

LaurenChoi_1J

9.2*1-^-31 is the mass of an electron I believe, which is where he got the number.

LaurenChoi_1J

Hi, so the problem tells you that the wavelength is 102.557 nm. Using the electromagnetic spectrum, we know that 102.557 nm lies within the wavelength range for ultraviolet light. Therefore, we now know that the light being excited to another energy level is ultraviolet light. Because of this, we c...

LaurenChoi_1J

For this question
“Light with a wavelength of 102.557 nm excited a hydrogen atom gas sample. What is the principal quantum level of the state that the electron was excited to?”

How do we know what the initial energy level was?

LaurenChoi_1J

Can anyone help me with this problem?

A violet line is observed at 434.0 nm in the spectrum of atomic hydrogen. Determine the values of n for the beginning and ending energy levels of the electron during the emission of energy that leads to this spectral line.

LaurenChoi_1J

Can anyone help me with this problem?

When an excited electron in a hydrogen atom transitions from an unknown energy down to the ground state, the light emitted is found to have a wavelength of 103 nm. What was the initial energy level of the excited electron?

LaurenChoi_1J

Can anyone explain the difference between the -hr/n^2 equation and the Rydberg equation?

LaurenChoi_1J

Same! Can anyone explain this question? It's very confusing to me

LaurenChoi_1J

Can anyone explain the statement in the lecture where electrons are not emitted even for high intensity light?

LaurenChoi_1J

Ahh got it! In the lecture, when he said that e(excess)=1/2mv^2, does that mean the amount of excess energy equal to the kinetic energy?

LaurenChoi_1J

Can anyone explain to me what the equation with the 1/2mv^2 is used for?

LaurenChoi_1J

Is the work function essentially the energy needed to remove the electron?

LaurenChoi_1J

Is the 1/2mv^2 formula the leftover energy after the electron has been removed?

LaurenChoi_1J

Ahh got it! And just to clairfy, the work function is the minimum amount of energy needed to remove the electron?

LaurenChoi_1J

can anyone explain the photoelectric effect to me? i'm very confused and lost

LaurenChoi_1J

Most likely there will always be a limiting reactant, unless you get a situation where the moles of reactants you calculated (based on the amount of each reactant you have) perfectly matches the required moles of reactant based on the balanced equation. And if there is only one reactant in the equat...

LaurenChoi_1J

i would just use whatever values are on the periodic table that Dr.Lavelle gives us and wait to round until you get to the final answer to make sure that your answer is as accurate as it can be.

LaurenChoi_1J

I'm think you're use M1V1=M2V2 for both questions but if anyone has different suggestions please feel free to let me know! I'm actually not 100% sure if the neutralization question is going to be solved in the same way, but most people who have replied to this question seem to have come to a consens...

LaurenChoi_1J

Density is g/ml. Since they gave you the density and the volume used, you can use the formula density=mass/volume to find the mass of the reactant and then use the molar mass to convert it moles and then use mole to mole ratio to determine how much product was created. Hope this helps!

LaurenChoi_1J

To solve this problem, the concept of molarity needs to be remembered. Since molarity is mol/L, to find the moles of copper(II) sulfate needed, we need to use 0.20M=(x moles)/(0.25 L). Once you solve for x, you need to convert the moles to grams by using the molar mass of copper (II) sulfate. Hope t...

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