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2:34 AM
0
A: A new Formatting Sandbox — please test stuff here

orthocresolThoughts on how to structure HW policy discussion Now, it's 2 am and none of this is set in stone, this is open to discussion. I'd like to mention that I actually came up with this independently and upon reading Martin's answer here we seem to agree on quite a few things. We can categorise que...

@M.A.R. ^
I'm trying to think about how we want to set out reworking the HW policy.
This is the approach I would take, but I'd just like to pass it through a few people first.
@Martin-マーチン, @Loong, @pentavalentcarbon, @Jan, @Mithoron, anybody else?
Of course, everybody's free to comment. I'd like to start the actual discussion about "what is a T2b question" in the next few days. (P.S. I know it's a lame name, but it's late at night and my creativity is zero. I just wanted a name that wasn't "homework".)
Basically, if I were to go ahead with the actual discussion, I would write it this way:
1. Explanation of why HW policy should go. (the reasons I outlined above)
2. "What are the the characteristics of bad HW questions that we do not like?"
3a. "Are there any types of questions, currently closed under HW policy, that cannot be justifiably closed in the new policy?"
3b. "Are there any other questions that you would like to see closed that are currently not closed, and why?"
 
3:23 AM
@orthocresol Why was this posted in the formatting sandbox and not as it's own post?
I think it would be better in terms of accessibility to make it it's own post
And only because I think it's very important for people to see and think about the issues you've raised
 
 
3 hours later…
5:56 AM
@ringo 'cause it's not done yet
 
6:14 AM
7
Q: Hydrogen bonding in staggered vs eclipsed conformations

Melanie ShebelLast semester in organic chemistry 1, we learned that staggered conformations have lower energy/higher stability. However, my thought is that if you have interacting OH groups, the hydrogen bonding would make the eclipsed conformations more stable. Is this be the case? Why or why not? For examp...

 
 
3 hours later…
9:01 AM
@ringo I thought about it, but I feel like I would prefer this stage to just be informal discussion.
I'm not soliciting ideas on what the new policy should be; I'm just trying to gauge how we should go about soliciting such ideas
i.e. It's meta-meta work. And I don't want everybody to get bogged down discussing it. That's my opinion at least
 
9:28 AM
@M.A.R. I'm thinking about how do we conclude amirite. This is headache-inducing.
Hmm, perhaps we can have the best of both worlds. Raw amirite questions can be closed under HW (or whatever the new policy is called) for not being conceptual. If OP (or somebody else) edits it to become a normal conceptual question with an answer, then we can reopen, and if the Q&A is good, use it as a dupe in the future. — orthocresol ♦ 32 secs ago
How about this?
Oh btw, PMQ = personal medical question.
 
9:46 AM
Oh
 
10:09 AM
No. It is my doubt. I know Birch reduction (Metal Reduction of Alkynes) and how that happens. However I saw this question in a paper. So I am wondering how reduction will happen. Anyway, thanks for reply. I will try to figure out if you don't tell. — Rohit 5 hours ago
The only thing worse than a homework question is a homework doubt.
3
 
user228700
10:29 AM
@orthocresol: U don't like ice cream?! :o
 
user228700
 
user228700
Reminded me of Ross ^
 
 
11:31 AM
@pentavalentcarbon ping I posted some questions in our chat, give them a quick look when you have some time :)
 
 
1 hour later…
12:57 PM
2
Q: Peculiar behavior of tea boiling with milk

THE LONE WOLF.While making tea last night I forgot all about it and left the kitchen. When I did remember about it, I ran back and I was surprised to see that it was still in the vessel (though it formed a peculiar foam-like mass on the top). This pushed me to do the same with water and milk (as these were ...

 
@ortho @M.A.R. o/
@M.A.R. What's with the somethinga-hedron?
To think I wanted to ask you this @Jan ._.
5
Q: Where does the label ‘Dq’ to denote the field split in coordination compounds come from?

JanAs established in a previous question, coordination compounds typically have a field split between the $\mathrm{t_{2g}}$ and the $\mathrm{e_g}$ d-orbitals.[1] This energy difference can be explained by the crystal field theory which assumes negative point-charges approaching a complex and destabi...

Great, now whom do I ask?
 
1:18 PM
@getafix sorry, I'm going to be pretty busy until the end of my work day today. But at some point I'll explain the theory input file you posted, your general ideas are correct. As for the spreadsheet results, think about the physics behind the helium dimer. What does the sign change mean?
@orthocresol I will read later
 
sure, real life is more important
 
@ortho How was the graduation? O.o
 
What graduation?
 
@orthocresol There was talk about you graduating ._.
'bout a week or two back.
And something about you saying you wouldn't be as active as you are right now on SE after graduating
Maybe I misunderstood the situation?
@ortho Darn, 2016 is going to be a very tight race ;) [ silently cheers on Trump ]
 
@AaronAbraham Yes you did. We were just joking..
 
1:34 PM
@orthocresol Damn insider jokes...mumble...mumble -_-
@getafix o/
 
@AaronAbraham
\o
 
@pentavalentcarbon Don't worry about, get back to me whenever you can, cheers! :)
moral dilemna: Roald Hoffman is giving a lecture at my university tomorrow I think
and I have class at the same time
should I skip class to go to his talk?
 
can you just change the timing of your class?
 
nope.
It is stupid ass class about architecure and civil engg
but i need the credit to graduate sigh
 
1:37 PM
Get someone to tape the class ._.
Watch it when you're free :/
 
and it is mostly an attendance grade, I wrote to the prof asking him to excuse me a week ago..I even said, I would hand in my assignment as usual.
son of bitch never replied, :/
 
Otherwise get someone to tape the lecture instead ;)
 
I actually don't care for the lecture lol
 
lol.. then what's the issue
 
Then why the dilemma?
 
1:38 PM
attendance is graded...
'lol
 
As for the lecture?
 
oh wait I care for hoffman's lecture
not my class lecture
 
So like I said, get someone to tape the Hoffmann lecture ;P
 
it's not the same thing
I want to be there..in the same room..
 
O.o
Ah
 
1:40 PM
I mean it is not everyday you get to here a nobel laureate speak
 
I know that feel... :(
 
I think I am just gonna cut class, and deal with the consequences later lol
 
Zhe
I've always thought of grading attendance as kind of narcissistic...
 
Can't you stay for like half the class, make an excuse, and then leave for Hoffmann's ?
 
@zhe I know right!!!!
Like you should make your lectures worth attending
I had a bitchy biochem prof who changed my grade from an A to B just because of attendance
 
Zhe
1:43 PM
Eh, grades aren't that important anyway :)
 
technically, I would always show up five mins before class ended lol
@zhe They're all I have..I need stellar grades otherwise no grad school would want me.
My university is not letting me get any research experience sigh :/
 
@AaronAbraham Eh, just new avatar
 
@M.A.R. But what is it?
 
Zhe
@getafix What year are you?
 
3rd
 
Zhe
1:45 PM
Are you doing research?
 
@AaronAbraham Dodecahedrane
 
Nope. :'(
 
Zhe
Not too late to find something for the summer. Makes it a lot easier to get into grad school.
Esp. if your adviser will write a good rec letter
 
@M.A.R. Next question, why a 12 faced 3D figure?
 
@M.A.R. I think you can probably wrap up amirite.
 
1:46 PM
@Zhe there's like whole story/scandal..
 
I feel too lazy now
 
Zhe
@getafix :(
 
Just accept Mart's answer
 
@Zhe basically my dept. fucking sabotaged my career.
bottom line.
 
No effing in this chat.
 
1:47 PM
or tried to..i mean whatever success i do end up finding would be despite them not because of them
@M.A.R. lol sorry
 
Nov 4 '15 at 9:35, by Jan
Adobe what the fuck did you to do to the Reader and how can I change it back? (ノಥ益ಥ)ノ ┻━┻
 
@orthocresol Did you just search for the F-word?
 
@getafix If I upvoted some of your questions, would that make ye feel better? 3:)
 
@orthocresol lol
 
@M.A.R. 'effin heck...
#serial_upvoter_lives_matter
Can't you guys allow a little charity?
XD
 
1:49 PM
@AaronAbraham
against the rules man, don't push it haha
 
@M.A.R. Yes.
Martin just asked a question.
0
Q: Formaldehyde from Urea?

MartinI was wondering if it is possiple to make formaldehyde from urea. I noticed they have a similar structure, but where the hydrogens in formaldehyde is replaced with two amide groups. Would it be possiple to remove those groups and replace them with hydrogen?

 
Is the Martin's sock haha?
 
@getafix Nah, just screwing around XD
 
@M.A.R. your sock has sock..
 
investigating
 
1:52 PM
NOOOO
 
XD XD XD XD
XD XD XD XD XD
 
:O
 
LOLOLOLOLOLOLOLOL
 
Zhe
1:53 PM
@getafix :( :( :( where do you go to school?!
 
1 1
 
BWHAHAHAHAHAHAHA!
 
PFFFFFFF!
 
@Zhe let's do it in a different room, if you don't mind?
 
1:53 PM
X'D
 
This is the real sock sock
 
This warrants a one-year suspension.
 
@M.A.R. Stahp please.
 
1:54 PM
Who for?
 
I did
 
Martin.
 
XDXDXDXDXDXD
 
The oneboxes are annoyingly large as usual
 
Zhe
@getafix Sure. Where do I find this other room?
 
1:55 PM
Create it?
 
@zhe you should get an invite
about now..
 
@M.A.R. Deserved a star
 
2:08 PM
1
A: The Rayleigh-Ritz variation method

WildcatInstead of doing the whole derivation, I will provide the following two hints usefull in the derivation: Use the quotient rule (as is was already done by OP). $$ \left({\frac {f}{g}}\right)'={\frac {f'g-fg'}{g^{2}}} \, , $$ where in this particular case $f = \sum_{i,j} c_i c_j H_{ij}$ and $g ...

We math.SE now.
 
0
Q: Can a table salt + vinegar mixture be explosive?

Aaron AbrahamI remember having read in a book, Ask Me Anything (Dorling Kindersley), that a combination of copious amounts of table salt and vinegar is explosive. Now this was a really long while back, and I can't even find my copy of the book anymore. But I'm quite sure there was a mention of salt+vinegar b...

We jihadist.SE now.
 
7
Q: Five-pointed crown alkane C25H40: does it exist?

Charles H. BennettMy 4 year old granddaughter, playing with molecular models, began making a cyclopentane ring, each of whose carbons bore a spiro-connected cyclopentane ring of its own , in the manner of spiro [4.4] nonane. If she hadn't run out of carbon atoms first, the result would have been a pentagonal crow...

We Chem.SE now.
 
Eh, I meant the "hint", not the content matter
To be fair it's not really a hint - iirc once you make those substitutions you arrive at the answer, so..
 
@orthocresol Lately I've been tempted to change my username to paracresol and replace my avatar with a picture of a black-brown seal. ._.
 
that'd just be irritating
btw, S doesn't refer to heat capacity..
 
2:15 PM
Then?
Specific?
 
i'm going to assume that it refers to the standard molar entropy
 
Edit away
._
My bad ortho ._.
 
there are two heat capacities $C_V$ and $C_p$
 
Anyways, bye! @ortho o/
Yea, one at constant vol, and the other at const. pressure...
 
yeah, and the specific heat capacities are usually denoted $c_V$ and $c_p$
 
2:18 PM
Ok, my bad X3
I'm assuming you've already corrected it?
 
you have the privilege, so just be careful with edits (I've screwed up some too)
 
Sure thing!
 
I'll edit it, don't worry
 
I'll be careful next time!
@ortho Tschüss o/
 
cya
 
2:20 PM
I'm pretty sure I'm gonna earn the 'Tumbleweed' badge on my latest question ._.
 
 
4 hours later…
6:30 PM
@Jan I want to make this clear: are you effectively saying that d orbitals don't actually form double bonds?
since such a bond would be very weak
 
Jan
6:47 PM
@Benzene Main group atoms d orbitals don’t form double bonds.
Transition metals’ d orbitals are well known to form double and triple bonds.
The thing is, consider e.g. sulphur. It is an element in the third period. The electron configuration is [Ne]3s²3p^4.
We all remember that noble gases are, well noble, and attribute this to their electron configuration of nnp^6.
The next electron to come in is the single one of the next period’s alkaline metal; after argon that would be potassium ([Ar]4s^1).
The 3d subshell is still higher in energy than the 4s subshell. Why on Earth should it take part in bonding to any non-neglegible extent?
This is different in transition metals, of course. Their 3d orbitals are energetically close to the 4s orbitals which is where chemistry is happening. Thus, these 3d orbitals can take part in single, double, triple bonds.
 
Zhe
@Jan what orbitals do you mix in if the S is hypervalent?
From an MO perspective
 
Jan
But once you’re past the d block in the fourth period, you have the configuration 3d^{10} whose energy has again been lowered due to core contraction etc; thus, selenium again won’t use either the (populated) 3d nor the (free but energetically removed) 4d orbitals.
 
@Jan I think that makes sense. What would sulfate look like then? Would it be four single bonds (sp3 hybridized)
 
Jan
@Zhe Well, you have a total of four orbitals of sulphur and four per oxygen atom.
@Benzene Pretty much, yes.
 
I had previously learned that sulphuric acid was so acidic because the negative charge produced by losing a proton could resonate with the two double bonds. If sulfate does not have double bonds, are the negative charges only stabilized by Oxygen's high electronegativity?
@Jan
 
Zhe
7:01 PM
@Jan fair
 
Jan
Each oxygen carries -0.5 negative charge, yeah.
It’s still well stabilised because symmetry and the high oxidation state of sulphur.
 
@Jan How do the oxygens carry -.5 charge? Are the 2 extra electrons in a super position between the four oxygens, or is this just an average calculation?
 
Jan
Average calculation.
 
kk, that makes more sense
Isn't the separation of charges unstable, though?
 
Jan
No, Pauling just thought it would be.
In Lewis structures it’s a mere formality anyway. In an MO depiction, orbitals always traverse the entire molecule.
 
7:08 PM
Orbitals always transverse the entire molecule? I know that is true for conjugated systems, but is that true for all orbitals?
 
Jan
Professor Zipse’s site also has a selection of other molecules, although some of them only show the pi system.
And then there’s the WOrbit site by Hans-Ulrich Wagner.
 
Thanks! I actually have class to go to rn, but I will look into this.
 
Jan
@AaronAbraham The person who answers.
(sorry at the other guys for replying to something lo~ng gone just now xD)
 
Zhe
7:44 PM
@Benzene Yes. The amplitude of the wavefunction might be quite small, but you can usually find some element of symmetry to mix some AOs into a given MO.
 
8:19 PM
@Zhe Does that happen in sulfate? If so, is there a meaningful difference between that and a double bond?
 
Jan
15
A: Is the bond enthalpy of S-O stronger in SO₃ or SO₃²⁻?

Martin - マーチンDue to symmetry constraints ($D_\mathrm{3h}$) in $\ce{SO3}$ there 6 electrons in $\pi$ type orbitals. In a wider sense of the term this molecule is Y-aromatic, but the HOMO actually represents two electrons in in-plane lone pair orbitals of oxygen. The LUMO is an antibonding $\pi$ orbital with re...

 
9:09 PM
Thanks for the help!
 
Zhe
I think you need some kind of NBO analysis to figure that out
I suspect it's like 1.5-ish but that would just be speculation
 
Jan
9:26 PM
@Zhe D’you mean bond order?
 
Zhe
@Jan yes
Maybe I misunderstood what Benzene was saying though
 
Jan
@Zhe Martin says in the answer linked above that he calculated SO3^2-’s bond order to be 1.1, which is neglegibly different from 1.
 
Zhe
9:41 PM
@Jan I was talking about sulfate... :/
Not sure there is a big difference though.
 
Jan
Yeah, but there are no reasons to believe sulphate behaves any differently ;)
 
Zhe
I no longer have Gaussian, or I would try this myself...
Short answer is I have no idea what I'm talking about :/
Also, it turns out that after you leave chem for a long time, you're very rusty...
 
Jan
@Zhe That’s a layman’s way of saying it. The chemist says oxidised.
(fun fact: to oxidise around or in German rumoxidieren was third place for youth word of the year in Germany in 2015)
 
Zhe
O_o
The kids, they get smarter every year
 
Jan
People have also criticised the winner of youth word of the year 2015, smombie of not being used by contemporary youths but being an invention of the jury =D
 

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