CHEMISTRY COMMUNITY

Veronica Soliman 4H

I do not feel comfortable using pen on exams. Would I be able to take the final in pencil please?

Veronica Soliman 4H

Poly: more than one
These can lose more than one proton.

Veronica Soliman 4H

I think the final grades will be curbed based on the averages for the midterms, quizzes, and finals. So if the average for the midterm was an 83, the highest score would probably set this curve and anyone below this would actually have gotten less than what they got.

Veronica Soliman 4H

If you imagine this in 3D space, you can see that it is trigonal pyramidal tetrahedral. It is easy to confuse this with it being bent but be careful not to make that mistake.

Veronica Soliman 4H

Nope! The only thing that affects hybridization is the electron configuration from what I understand. For example, a linear electron configuration means that the hybridization is sp.

Veronica Soliman 4H

It's polar if it's got a dipole moment which means the little arrow with a plus sign points toward the more electronegative element (usually oxygen, occasionally carbon...etc) This is only polar if the dipole moments cancel out. You can have a situation where there are dipole moments and it is nonp...

Veronica Soliman 4H

005199302 wrote:CO2 is father apart, but CS2 is more electronegative

How do you know this?

Veronica Soliman 4H

Sigma bonds allow bound atoms to rotate resulting, the sigma bond has electron denity and has cylindrical symmetry around the internuclear axis. It is also more stable. Pi Bond make it impossible to rotate or pi bond breaks, restriction on double and triple bonds, when 2 atoms are bound, then addit...

Veronica Soliman 4H

LOOK FOR THE DIPOLE MOMENT that doesn't cancel to 0. For example, hydrogen bonding is polar because it is a dipole-dipole interaction whereas weaker intermolecular forces like van der waals are nonpolar.

Veronica Soliman 4H

Emily Li 4A wrote:
DavidEcheverri3J wrote:Will we also need to know the degrees of the shapes?

I think it's very likely that we have to know them, but at least we can use simple math to find angles in most of the shapes.

I think it's helpful to know the molecular structure, electron structure, angles, and the way it looks.

Veronica Soliman 4H

It's polar if it's got a dipole moment which means the little arrow with a plus sign points toward the more electronegative element (usually oxygen, occasionally carbon...etc)

Veronica Soliman 4H

Do lots of problems

Veronica Soliman 4H

Expect the unexpected.

Veronica Soliman 4H

Hey! you can do any problems from the material that we've previously covered as long as there are 14 (instead of 7) problems completed.

Veronica Soliman 4H

Ok bonds exist with signma bonds and pi bonds are rigid whereas signma move usually in double bonds.

Veronica Soliman 4H

You have to look at this in terms of covalent and ionic bonding.

Veronica Soliman 4H

We did a demo in class where if it’s 4 bonds, you just recall it’s a 3d shape so while you would think it is 90 degrees, it’s actually 109 because it’s 3dinensional. The first 3 are pretty self explanatory so 2 bonds would likely be farther apart and are at 180 degrees.

Veronica Soliman 4H

Additionally, anything that is in the 8th valence shell area will not need to have covalent bonds or ionic bonds because noble gases are already full and happy.

Veronica Soliman 4H

For homework 6 are we allowed to answer any problems from any previous sections that we've learned or is there a cutoff for which problems we are allowed to do?

Veronica Soliman 4H

YES! 1. Count valence electrons (left to right on periodic table using s and p only - I think) 2. Create molecule's lewis structure 3. Find the FC of each molecule, Subtract the valence # of each molecule by the amount of dots and lines for each. 4. Try to rearrange to get it to be the most stable i...

Veronica Soliman 4H

Can we use a pen with erasable ink?

Thank you.

Veronica Soliman 4H

ml specifies a specific orbital. The D subshell itself has 5 orbitals (ml= -2, -1, 0, +1, +2) and therefore two electrons in each (10 total). However, the ml= -2 specifies that it is one of these 5 orbitals, which can only contain two electrons. Can you further explain this? Still confused. Sure! T...

Veronica Soliman 4H

Where is our midterm held today??? If you are in the 2pm lecture, it is at Moore 100 It's based on last name and we are split into multiple rooms. MT is from 6-8 pm The rest of the information is from Dr. Lavelle's post on his website: 14A-1, 10am class: Last name A-L in HAINES 39. Last name M-Z in...

Veronica Soliman 4H

Sona Hakobyan 3J wrote:ml specifies a specific orbital. The D subshell itself has 5 orbitals (ml= -2, -1, 0, +1, +2) and therefore two electrons in each (10 total). However, the ml= -2 specifies that it is one of these 5 orbitals, which can only contain two electrons.

Can you further explain this? Still confused.

Veronica Soliman 4H

Referring to chapter 2 in 6th edition #'s 2.53 and 2.51

Asking to find unpaired e- in Bi, Si, Ta, and Ni
Also how many unpaired e- in Ga, Ge, As, Se, and Br? How do you solve these?

Veronica Soliman 4H

Number 29 in chapter 2 asks to give the number of electrons when given a certain n, l, or ml value. Part b says n=4 l=2 and ml=-2. I get that it would be 4d and without the ml value it would have 10 electrons, but the solutions manual says it only has 2 electrons and I was wondering how the ml would...

Veronica Soliman 4H

Hi,

I was wondering if schrondinger's equation would be on the midterm? We barely covered it in lecture and there is no module to teach it. Is there someone who can explain it or let me know if we need to study this topic?

Thanks.

Veronica Soliman 4H

I think this might have to do with the octet rule, but I am not certain.

Veronica Soliman 4H

Hi I haven't received my test 2 back yet, but when I do, I will be sure to reply here. Could you post the actual question on here so I can assist?

Veronica Soliman 4H

I believe they will be after the midterm and after thanksgiving

Veronica Soliman 4H

Which modules are recommended for module 2? They weren't listed in outline 2 so i'm uncertain.

Veronica Soliman 4H

I'm v confused because one module spent 26 mins talking about how light was in waves and that mu*lambda= velocity (c speed of light) and another said that light wasn't in waves. So I'm v confused. Can someone explain this please?

Veronica Soliman 4H

Dr. Lavelle has a list of solution manual errors. This one is not on there, but here's the link for reference:
https://lavelle.chem.ucla.edu/wp-conten ... rs_6Ed.pdf

Veronica Soliman 4H

It's after thanksgiving!

Veronica Soliman 4H

I do not think we need to know the Black Body effect. Dr. Lavelle discussed this in lecture and said he did not want to spend too much time on it.

Veronica Soliman 4H

daisyjimenezt wrote:No need to memorize, they'll be provided. If you do want to remember them, focus on memorizing their derivations

'

Anyone know if they're provided on the mCAT also?

Veronica Soliman 4H

Josephine Chan 1B wrote:Yes, according to the test and exam schedule, we have the midterm on Nov 5 and then the next test is on the week after Thanksgiving break.

When is thanksgiving break? During which week and is it just thursday friday? 4 day weekend?

Veronica Soliman 4H

R=3.29*10^15 s^-1 which helps s calculate c=v*lambda v= R ((1/n1^2 - 1/n2^2) so when plugginf this into c=v*lambda, we get c= 2.997 * 10^8 m/s which is in velocity units... so after finding all variables, we now want to solve for lambda which can be found by plugging in n1^2=4 and n2^2=16 I hope thi...

Veronica Soliman 4H

Thank you so much! I hope all is well in med school!

Veronica Soliman 4H

Can we use atoms or molecules interchangeably when solving for problems that ask for converting moles to either or?

Veronica Soliman 4H

I don't have this directly in front of me, however, as a general rule of thumb, look in the question itself for the number with the least sig figs reflect that in your answer.

Veronica Soliman 4H

Christine Chow 4G wrote:i dont have the seventh edition, but the energy of a photon = h (Planck's constant)* v (frequency)

However, v is actually "mu" not v.

Veronica Soliman 4H

In addition to everyone's comments, I'd recommend you be very careful when determining the state of water (because it has 3 states), it is best to read the question carefully and determine if the other reactants and products are hot/cold/room temperature.

Veronica Soliman 4H

One important tip that my TA actually spoke about was if you keep going back and forth while balancing reactions, it's probably wrong and it's best to attempt that problem from the start.

Veronica Soliman 4H

For e.15 on the homework, can someone explain what is meant by M? There’s no element that’s just M? I’m so confused

Veronica Soliman 4H

When we write out chemical equations for either balancing or finding yield, is it necessary to define whether each compound is a liquid, solid, gas, aqueous? Additionally, would someone mind explaining in the simplest terms what aqueous means? I haven't taken basic/regular chem since 4 years ago so ...

Veronica Soliman 4H

Also, would someone let me know how to post a question? I couldn't figure out how and I've tried reading the FAQs

Veronica Soliman 4H

I don't know how to post a question, but related to this topic of rounding:

if your emperical ratio is 1:6.012 can your final answer be for example C1H6 or does it have to be to the next nearest whole number of 5 and 30? Could that work?

Veronica Soliman 4H

In short, yes both of these mean the same thing. It is a large textbook and has been edited several times before publishing, therefore, different authors may have changed the notation. They still mean the same thing. Hope this helps.

Veronica Soliman 4H

It's literally what happens at the beginning (or the mass at the start (mass initial)) is going to be equal to the mass final. This is usually done as was done in lecture today where we were given n = Moles*liters and given a question would just plug in the given values of of (M)*(v-liters) initial ...

Veronica Soliman 4H

Hi, since we're still doing homework and still haven't been taught this, I'd just say to look it up. Some things we can memorize later on, but for now, I think it is thoughtful to google search this if possible. I hope that if we aren't taught this by the first midterm, that we can be provided with ...

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