CHEMISTRY COMMUNITY

Esther Lee 4H

Manu Vohra 1L wrote:Yes, he is but it will probably not be posted before tonight or tomorrow as I am sure he has his own finals too.

makes sense. thank you so much! I just wasn't sure if he was making one

Esther Lee 4H

I was wondering what types of biological examples we need to know for the final.
I know we've talked a bit about ATP hydrolysis so I think it's safe to assume there will be a question about that but what else is pertinent to the final?

Esther Lee 4H

Hey Ben!
In lecture he said if it's not given to you to just assume that the value is 1

Esther Lee 4H

hi does anyone know if Lyndon is making a review practice for the final or what it's called if it's already been posted?

Esther Lee 4H

Jordan Lo 2A wrote:Do we know how to find the order or will it be given?

The hw questions I did mostly gave it to you and told you that it was first order or something else so I think it’s given to you but someone correct me if I’m wrong please

Esther Lee 4H

Zero order: mol.L^-1.s^-1 or M/s
First order: s^-1
Second order: L.mol^-1.s^-1

I believe it was a homework question on the 6th edition #9 under the kinetics chapter

Esther Lee 4H

The 2.0 is derived from the experimental data. I’m pretty sure it will always be given to us if we need it for hw problems or on a test

Esther Lee 4H

shaunajava2e wrote:Gibbs free energy and electrochemistry up to but not including the Nernst equation

thank you!

Esther Lee 4H

and does anyone know what sections that covers in the sixth edition textbook?

Esther Lee 4H

does anyone know what sections are going to be on the test this week?

Esther Lee 4H

Mindy Kim 4C wrote:Since the question asks for residual molar entropy, they are asking for the residual entropy for one mole of SOF2. There are 6.022x10^23 molecules (Avogadro's number) in one mole.

ohhh that makes a lot of sense thank you

Esther Lee 4H

how do you know how many molecules are present?

Esther Lee 4H

it is on the whole molecule so if you have O2 it is 1 because its only oxygen

Esther Lee 4H

9.25: if SO2F2 adopts a positionally disordered arrangement in its crystal form, what might its residual molar entropy be? I know you use the S=Kb*ln(W) equation and that it has 6 possible orientations but how would I know how many molecules are in it? the answer book says ln(6^6.02x10^23) but where...

Esther Lee 4H

im also struggling on 14 if anyone could help out

Esther Lee 4H

does anyone know how many questions are gonna be on the midterm and how many questions from each section??

Esther Lee 4H

this is so pure omg

Esther Lee 4H

im not sure if there's like a rule for it but it seems like we've been using bar way more than atm. they're both measuring pressure so I dont think there's a specific one you need to use but someone correct me if I'm wrong please

Esther Lee 4H

also, does anyone know when it's at and where?

Esther Lee 4H

what do I need to type into the search bar to find the midterm review sheet?

Esther Lee 4H

in Lavelle's slides he wrote that you can heat or cool the system then noted in parentheses that its for a closed system but I know that it would work for both a closed and open system. so I was wondering if for the next bullet point that says "do work on the system" what systems does that...

Esther Lee 4H

depends on the type of question. if youre not given too much information it might be easier to set up a table but if youre able to solve it through hess' method you can do it that way

Esther Lee 4H

I think it just means that there is little to no chance of the system being affected by the surroundings

Esther Lee 4H

when you break the forces youre inputting heat so its considered an endothermic reaction

Esther Lee 4H

I'm pretty sure it is the atp production but i'm sure he'll bring up another example if we're wrong

Esther Lee 4H

yes heat energy is a state property

Esther Lee 4H

^^ I was also wondering if this was a possible I feel like you can depending on the complexity of the equation but what else does it rely on?

Esther Lee 4H

wait sorry never mind there's a step up session from 7-9 pm in covel 210 by Ashley

viewtopic.php?f=160&t=40228

Esther Lee 4H

at the end of the 3 pm lecture he said that they were cancelled and will resume Tuesday

Esther Lee 4H

dont know what the question says but I think for most questions it specifies to solve for either one or the other or both

Esther Lee 4H

you still include it in the K and Q calculations. only solids and liquids are omitted from the calculations

Esther Lee 4H

if its heterogeneous with solid and a liquid in the balanced equation we wouldn't include them in our calculations for K and Q

Esther Lee 4H

this is a dumb question but what does bar mean? I know its only used for pressure but is it like a unit?

Esther Lee 4H

I went to Lyndon's review session and he said its best to just memorize them

https://quizlet.com/21890142/common-str ... ash-cards/

this quizlet might be helpful

Esther Lee 4H

405112316 wrote:I definitely think we should know cisplatin! It is the well known chemotherapy drug that forms coordination compounds with DNA to stop cell division. The two chlorides are on one side and can bond with the guanines in two separate locations to effectively stop uncontrolled division.

thank you!!

Esther Lee 4H

thank you!!

Esther Lee 4H

Elements with an octet expansion exception begin in the 3rd row because in this row n=3, therefore l=0,1,2 : meaning that electrons of an element in the 3rd row can lie in a l=0 s orbital, a l=1 p orbital, or a l=2 d orbital. Because the 3rd row elements have access to bonding with d-orbitals, they...

Esther Lee 4H

you can have multiple pi bonds because there are 3 p orbitals

Esther Lee 4H

pi bonds cannot rotate

Esther Lee 4H

Generally, try to visualize the structure based on the number of bonded pairs and lone pairs. You can guess some structures from the name, eg. trigonal planar or trigonal pyramidal, but for the most part you should try to memorize the common ones. Here is a chart for your reference: https://images....

Esther Lee 4H

did y'all hear about the guy who got cooled to absolute zero? he's 0K now

Esther Lee 4H

thank you!!

Esther Lee 4H

https://i.pinimg.com/originals/8c/76/d0 ... bf7f24.png

here's a chart I've been using. you probably don't want to rely on it since we won't have it on the test but its been helpful for me to double check my answers with it before looking in the solutions manual

Esther Lee 4H

Shouldn't the molecule be linear? If the chlorine atom has two lone pairs and two bonding pairs. if there are two lone pairs and two bonding pairs it should be bent. I know it sounds weird bc the two bonding and lone "cancel" each other out but if you think about it, we all know the shape...

Esther Lee 4H

some of them are kinda obvious like the 180 and the 120 but the odd ones like the 109.5 for the tetrahedral would be helpful to memorize. my TA was talking about how in past tests all they've asked before was to determine the shape and bond angle so it's probably best to memorize to get easy points ...

Esther Lee 4H

so I don't know how to attach photos into this so if someone can help me with that, that'll be great but I found a chart online that's really been helpful for me to determine molecular shape ill insert the link below bc I don't know how to insert images... https://i.pinimg.com/originals/8c/76/d0/8c7...

Esther Lee 4H

I had this same question and this website answered most of my questions hope it helps!

https://www.chem.purdue.edu/gchelp/liqu ... perse.html

Esther Lee 4H

From what I remember about high school chemistry though, bond length is determined by the bond order. So if there's more bonds between electrons, the stronger the pull, and therefore a shorter bond length. triple bond < double bond < single bond. single bond should be the longest because there are o...

Esther Lee 4H

I remember in lecture Dr. Lavelle said something about looking the bond length up which I'm guessing means we need to be given enough information to solve for it if not I think it might be given to us.

Esther Lee 4H

davidbakalov_lec3_3A wrote:When you divided all values by 3.15, you should have gotten about 1.14 for C. This is not close enough to 1 to round, so you should've multiplied all numbers by 7.

oohhh you're right. duh. thank you!!

Esther Lee 4H

so I worked out #2 on the practice midterm and got C22H44O22 but the answer is C24H42O21. Does anyone know where I messed up? I first divided all percentages by the mass of the individual element. the smallest value after I did that was oxygen which was 3.15 so I divided all values by that number an...

Esther Lee 4H

it's just a rule that says you need to have a filled shell valence electrons in order for the compound to be "happy" and "satisfied" with their situation. since the goal is 8 valence electrons for a lot of the most abundant elements, it's just called the octet rule but the main g...

Esther Lee 4H

there is no way to tell just by the calculations if its between the two numbers you would have to look at other characteristics in order to find out

Esther Lee 4H

this is gonna sound really dumb too but it's easy to remember that cations lose electrons because its a "pawsitive" ion and an anion stands for "a negative ion"

Esther Lee 4H

I was always under the assumption that if you imagined the atom as a box, you had to have at least one dot on each side before going around and adding more dots. so for something like oxygen with 6 valence electrons, you would put a dot on all 4 sides of the "box" instead of putting 2 dots...

Esther Lee 4H

because nonmetals are more likely to gain electrons in order to reach a full valence shell, they will most likely be anions

Esther Lee 4H

understanding the trends of the periodic table make it easier to understand the nature of the atoms and what way they'll react in order to reach a stable valence shell. for example, something like sodium is more likely to lose 1 electron in order to create a full outer shell rather than gain 7 elect...

Esther Lee 4H

I think it was Monday's lecture but I had a question about why he put the electron configuration of nitrogen as 1s1 2s2 2px1 2py1 2pz1 on the slides but when he did an example on the board for aluminum he put 1s1 2s2 2p6 3s2 3p1 instead of writing out each p orbital. in what case would you write out...

Esther Lee 4H

he said we only need to know the 4 for now I don't know if that means we're gonna cover the rest in the future or not but at least for this test we only need to know s,p,d,f

Esther Lee 4H

I'm confused as to what information the 4th quantum number gives. I know the combination of the first three specify the orbital and that the fourth gives you the spin state but what does that mean?

Esther Lee 4H

the Q1 and Q2 are both charges and the R is the distance between the two charges. I'm pretty sure we'd be given enough information in the question to solve for all variables if we were asked to solve a question like this.

Esther Lee 4H

I find it easier to change units in the end since there's less of a chance of messing up the entire equation when you do it at the end compared to the beginning.

Esther Lee 4H

I feel like this is a pretty simple question but I can't seem to find it in my notes. So there's a minimum length of a wavelength that's considered to small to be measured but is there a maximum? If so does anyone know what it is?

Esther Lee 4H

Going off on this does anyone know if we need to memorize the polyatomic ions for future tests or will they be given to us? Also will we always be given a periodic table?

Esther Lee 4H

is it necessary in a chemical equation to have the states of the compounds following the compound? like do I have to put solid, liquid, gas, to aqueous after each one? and how do you know if it's not given to you in the question?

Esther Lee 4H

I'm pretty sure it's okay to do it when the number is quite large too. so if the answer is 18,000,000 you can always put that as 1.80x10^7 it doesn't have to be only when the number is really small but someone please correct me if im wrong

Esther Lee 4H

in response to the above question, I think my TA today said that it's based on how correct it is. but we always have the solutions manual to guide us through so we can double check our work and make sure it's the correct answer and it's probably best to show every step so when you look back at it yo...

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