The Periodic Table - 2016-10-04 (page 1 of 2)

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2:26 AM

Is @Martin-マーチン looking to be re-elected as moderator?

Not sure if it's just too early in the nomination phase or what

Perhaps I'm too stupid but I couldn't figure out how to nominate someone else

user228700

3:24 AM

Hi everyone :-)

Hi

Shubh prabhat

> I am a passionate enthusiast in the fields of science, mathematics, literature, music and reducing world suck.

Maybe "reducing sickness?"

Fighting diseases?

user228700

@CowperKettle Suprabhat :-)

user228700

@CowperKettle No, no:

user228700

urbandictionary.com/define.php?term=WorldSuck

pentavalentcarbon

@ringo Once you're moderator, you remain moderator for life unless you choose to step down or you've done something terrible and are forcibly removed.

user228700

3:30 AM

I have a small question; does the common ion effect reduce the degree of dissociation, $\alpha$ of the weaker electrolyte?

@Kaumudi (0:

user228700

@CowperKettle :-P

user228700

@CowperKettle: Are u familiar with the common ion effect, sir/ma'am?

@Kaumudi No, I know very, very little chemistry

user228700

@CowperKettle Whaat? OK :-(

user228700

3:38 AM

@pentavalentcarbon: What about u..?

user228700

@JohnRennie: Does Le Chatelier's principle directly affect the degree of dissociation of the reagents involved in the reaction?

Martin - マーチン

@ringo We, the team of mods on chem.se, decided that we could use some backup. We are only extending our circle, so that the site stays functional if unexpected things, i.e. life, get in the way of our duties. At the same time everyone of us decided to continue the modding life. We are looking forward to welcoming new people in our midst.

@Kaumudi Hi :D Nice pizza-pic!

Hi @orthocresol!

Morning @Martin-マーチン

Oops!!!

On mobile, wrong copy paste...

I cannot understand why did Martin commented the way it is generally done to newcomers. From the reputation of orthocresol, it seems that that he/she is quite acquainted with the site. — Apoorv Potnis 6 hours ago

^^

Martin - マーチン

:32703255 Haha... and I was just about to ask: wut?

user228700

@Martin-マーチン Hi. Thanks! :-D It's called "The pizza John".

Martin - マーチン

3:50 AM

@orthocresol this is a good one ;) I'm glad I confused someone :P

@Kaumudi Yeah I know it! That's why I like it :D

user228700

@Martin-マーチン Oh! You're a Nerdfighter too?

Martin - マーチン

I like their videos, wouldn't really call me a nerdfighter though. But time will tell, maybe I will become one ;)

user228700

@Martin-マーチン That's awesome!

@pentavalentcarbon that I did not know... Thank you

@Martin-マーチン I'm glad to hear you're staying

Martin - マーチン

Thank you :D I think I still have a few good years before retirement ;)

3:56 AM

Yeah! Chem.SE is just getting started!

@Wildcat Why are we starring illegal things? ಠ_ಠ

stars it anyway

I've rarely had to resort to it, except when I had to look up an article in Heterocycles...

That thing is so expensive, even Oxford doesn't subscribe to it hahaha

Martin - マーチン

It's blocked in my university...

:(

It is illegal, I suppose.

Martin - マーチン

4:13 AM

hmmm... something happened... I just wanted to try an reproduce the category it's in (9gag for example is adult material/porn), but it's unblocked now O.o

It's a trap!

Martin - マーチン

I'm sure of it...

@Wildcat Are you happy now? We have so many choices already and that's not even counting you!

@Martin-マーチン On eduroam, they let you torrent stuff, but the moment you do so you get banned from the Internet. I had a friend who learnt that the hard way. For the next month or so, he had to borrow someone else's account to access the Internet.

However, I never got banned for illegally obtaining scientific papers or textbooks... so...

Martin - マーチン

@orthocresol I didn't know that... on the other hand, i hardly use torrents any way. I think the last time I used it was to download ubuntu 12.04

user228700

@orthocresol @Martin-マーチン: Do you know the answer to the question that I asked?

Martin - マーチン

4:20 AM

@Kaumudi Pardon, which question are we talking about?

user228700

This one:

user228700

51 mins ago, by Kaumudi

I have a small question; does the common ion effect reduce the degree of dissociation, $\alpha$ of the weaker electrolyte?

Martin - マーチン

Voting to reopen so that it can be closed as a duplicate. chemistry.stackexchange.com/questions/59822 — orthocresol Sep 27 at 12:38

lol

@Kaumudi hmmm I'm not sure, let me have a moment to think about that

@orthocresol You can now put a closevote on that

@Kaumudi Yes I'd think so. chemistry.stackexchange.com/q/531/4945

If you have $\ce{BaSO4}$ sat. solution and add $\ce{H2SO4}$ then more barium sulfate will precipitate, hence the number of molecules dissociated decreases.

user228700

@Martin-マーチン Hm, OK.

user228700

Let us consider then, the dissociation of $10^{-6}$ M HCl in aqueous solution of water. Since the concentration of the acid is so low, contributions of [$H_3O^+$] from water can't be ignored. However, the degree of dissociation of water decreases, due to the presence of the dissociated [$H_2O^+$] from HCl.

4:35 AM

I always thought that degree of dissociation is defined for weak acids/bases.

user228700

Despite this, $K_w=10^{-14}$?

@Martin-マーチン Actually, I can't. o.o I think it is because I voted to close the first time round.

user228700

@orthocresol Are u suggesting that we can't define the degree of dissociation for water?

I don't know. I feel like most of this is semantics

One doesn't really care how much water has dissociated. One cares what the concentration of H+ in the resulting solution is.

Martin - マーチン

@orthocresol awww...

4:40 AM

nominates myself so that I can unilaterally close questions

@Kaumudi Let's say, that we have 10^-6 M HCl.

user228700

@orthocresol This is how it works for strong bases, correct?:

Martin - マーチン

@orthocresol well, you should. Not for that reason obviously, but you should consider anyway ;)

It's done now. I used my modding power...

@Martin-マーチン I have a 13 hour flight coming up, so I'll think about it..

Martin - マーチン

uhhhh... where are you going?

user228700

user image

user228700

4:44 AM

^Acids

user228700

Is this correct?

@Martin-マーチン Singapore to London. Third year is starting next week ^^

@Kaumudi Yeah, so I guess you say the degree of dissociation is 1, but that's not a very useful piece of information, since you and I already know that strong acids fully dissociate in water.

user228700

@orthocresol No, I wasn't making a point. I just wanted to make sure that I was correct in writing that. Now, if we've got $10^{-6}$ M HCl, it would be wise to consider the [$H^+] coming from the water too, but water being the weaker acid, is affected by the dissociation of HCl. Am I correct, so far?

@Kaumudi Yes.

I suppose so. I don't know

user228700

@orthocresol OK, so the dissociation of water in the presence of our $10^{-6}$ M HCl would look something like:

4:54 AM

The issue is that, in such a solution, the total concentration of H+ is not 10^-6 + 10^-7.

user228700

@orthocresol Exactly! Because of the common ion effect, water doesn't dissociate to give $10^{-7}$ mols of $H^+$

That is approximately the case, but not quite, because you run into a contradiction.

Yes. Water doesn't dissociate to give the full 10^-7.

user228700

@orthocresol What do u mean..?

If water is generating 10^-7 H+, then it must also be generating 10^-7 OH-, by stoichiometry.

user228700

@orthocresol Right, but $K_w$ still remains $10^{-14}$? How?

4:56 AM

However, you then have a contradiction because [H+][OH-] =/= 10^-14 anymore.

Exactly.

Which is why, the total concentration of H+ is less than 1.1 x 10^-6.

user228700

@orthocresol Hang on please, I don't understand your point. Can u please elaborate..?

@Kaumudi Earlier we established that [H+] = 10^-6 + 10^-7 = 1.1 x 10^-7.

However, that calculation also means that [OH-] = 10^-7, by stoichiometry.

So, [H+][OH-] = 1.1 x 10^-14, which cannot be true.

user228700

@orthocresol When?!

Oh well, ignore that.

You never said that.

A lot of texts say that, and I assumed that that was what you were going on.

So, we established that water doesn't dissociate to give the full 10^-7 M of H+.

So, I guess you could say that, here, the degree of dissociation of water is decreased.

user228700

@orthocresol Yeah, OK...

5:01 AM

Is that what you were looking for?

I got too carried away, I think.

So many flags coming from h bar...

Drama! Drama!

user228700

@orthocresol No, see, I'm just confused about how $K_w$ remains $10^{-14}$, even though the dissociation if water us affected. Ik that $K_w$ is a dissociation constant and that it only depends on temperature but still...

user228700

Can you explain that?

user228700

@orthocresol Sigh.

@Kaumudi Ok. We should start with a definition of $K_w$.

user228700

@orthocresol OK...

5:05 AM

K_w is defined by the expression [H+][OH-]. Nothing more, nothing less.

Martin - マーチン

@orthocresol those bastards...

Interpreting K_w as the "dissociation constant of water", is therefore only accurate when there are no other species that can give rise to H+ or OH- ions.

user228700

Yeah, I know, but see, if [H+] decreases, it's not like [OH-] will increase, no?

In fact, it will.

It necessarily has to, because no matter what solution you have, [H+][OH-] has to remain equal to 10^-14.

But, not all of the H+ or OH- has to come from water. So, one cannot still insist that water dissociates to give 10^-7 H+ and OH-, when there is another species that generates H+/OH-.

user228700

@orthocresol It will? OK.

user228700

5:08 AM

Okay, that clears it up. Thanks! :-)

user228700

(And also, how do u see these flags?)

Glad it helps. Sorry for being unnecessarily long-winded.

I don't know, I think you need a certain amount of rep? Not sure.

@Martin-マーチン Yeah... I don't dare to step inside there actually :/

@Martin-マーチン flags as offensive

user228700

@orthocresol Ohh, OK, 'cause I don't see no flags :/

Martin - マーチン

yes you need to obtain 10k chat rep

it's your site rep + lines you send (I think)

boosting chat rep

a

b

c

d

e

f

Martin - マーチン

5:12 AM

damnit, I was waiting for g h i to put c-c-c-combobreaker! in between

^^

@ringo, you nominating this time round?

5:32 AM

Gee, I hadn't thought about it

You?

I think there are many more qualified than I

@orthocresol

@ringo prolly not

Yeah... I'll wait for the 2018 elections or some far off year lol

If ever

In 2025 I will become overlord of chem.SE.

When you reach the rep singularity

Candidate score of 41/40

5:37 AM

You absorb all other accounts and become the entirety of Chem.SE

Hehe

I accept my fate

I did think about it.

But especially since Loong nominated, I think it's fine.

And I don't have a good answer to the question of how modding makes me any different from the 10k user I am now

Analytics and question protection?

Too simplistic? lol

Haha, yeah, but any mod can do that. I just need to badger Loong incessantly in chat if I want to get something protected.

Or, I could repeatedly create new 1-rep accounts and submit low-quality answers with incorrect nomenclature.

2

If that doesn't get him to protect a question, I don't know what will :D

5:43 AM

LOL

Martin - マーチン

@orthocresol you could get suspended for that....

jonsca is good at finding those sockpuppets

@Martin-マーチン How does one tell anyway? IP addresses?

Ancient Chinese secret

Martin - マーチン

I'm not sure. I think so. I have not mastered that science yet.

;D

No wonder I haven't been caught yet.

Martin - マーチン

5:50 AM

I am so glad we have the veterans on the team. I still feel like a n00b on many things around here. It's gonna be awesome because I won't be the youngest mod anymore :D

Martin - マーチン

6:03 AM

Questions about computations (software support) are generally not on topic here; they are also not really on topic on [compsci.se]. However, I do find merit in questions like this one and I am afraid it will be deleted soon. Should we overthink our policy on that?

Sorry, no input from me on that..

2 hours later…

8:20 AM

What does it mean that lone pairs contribute to orbital mixing?

8:38 AM

@orthocresol why does Ag only bond to two ammine?

Is there a way to determine the number of ammines each atom bond to?

8:55 AM

why is giant covalent structure stronger than giant ionic structure?

9:05 AM

Linear coordination is very common for d10 metals. Cu(I) forms a lot of [CuX2]- complexes. Ag(I) is no different. Hg(II) as well.

As for why, don't ask me, go and ask it on main site.

I don't know.

9:18 AM

@orthocresol which orbitals are involved in diammine silver? what about tetraammine copper (ii)?

=^.^=

@Martin-マーチン that is very hard to decide :|

Such questions seem to belong nowhere on SE network.

Martin - マーチン

yeah, but this will likely be quite helpful for future visitors, since the g09 manual is not very explicit about it

@DHMO probably that an AO holding a lone pair contributes to some MO...

@Martin-マーチン Gaussian manual is terrible overall. XD

Martin - マーチン

indeed, but there is worse

GAMESS for example

not even crosslinks...

:D

Martin - マーチン

9:27 AM

spread over couple of files...

you never open the one that you will need in the end...

@_@

Can we say "We used the MALDI-TOF-TOF system in positive ion, linear mode"?

It's both in positive ion mode and linear mode

@Martin-マーチン could you help me?

the questions i asked above

Martin - マーチン

maybe

half an hour ago

Martin - マーチン

14 mins ago, by DHMO

@orthocresol which orbitals are involved in diammine silver? what about tetraammine copper (ii)?

user116211

9:36 AM

It's @ph13!! Make Chem.SE great again!!

user116211

@martin Is there any separate chatroom for the Election purpose?

Martin - マーチン

2016 Chemistry Moderator Election

Open Discussion for chemistry.stackexchange.com/election/2

@Martin-マーチン yes, could you answer it?

user116211

@Martin-マーチン okky.

wait... 2s has two phases??? (shocked)

my life is a lie

Martin - マーチン

9:45 AM

@DHMO not at the moment, it's a bit complex... but this paper might pubs.acs.org/doi/full/10.1021/ja0176604

pH13 - Yet another Philipp

@MAFIA36790 that’s what all is about

9:56 AM

@Martin-マーチン private access...

user116211

10:07 AM

@DHMO use Sci-Hub

@MAFIA36790 onion...

user116211

@DHMO Er... what?

@MAFIA36790 look at the url of the website you just gave me

it contains onion

.onion is a special-use top level domain suffix designating an anonymous hidden service reachable via the Tor network. Such addresses are not actual DNS names, and the .onion TLD is not in the Internet DNS root, but with the appropriate proxy software installed, Internet programs such as web browsers can access sites with .onion addresses by sending the request through the network of Tor servers. The purpose of using such a system is to make both the information provider and the person accessing the information more difficult to trace, whether by one another, by an intermediate network host, or...

user116211

@DHMO So?

@MAFIA36790 is it related to TOR?

user116211

10:10 AM

Sci-Hub changes its url day in and day out.

@MAFIA36790 then how do you know the url?

user116211

Sci-Hub is an online search engine with over 58,000,000 academic papers and articles available for direct download, bypassing publisher paywalls. New papers are uploaded daily when accessed through educational institution proxies, and papers that have been accessed through Sci-Hub are stored in the LibGen repository. Sci-hub was founded by Kazakh graduate student Alexandra Elbakyan in 2011, as a reaction to the high cost of research papers behind paywalls, typically US$30 each when bought on a per-paper basis. Sci-Hub follows the general open access movement of the 1990s, and a number of smaller...

user116211

@DHMO googling

@MAFIA36790 onion that appears in google...

> Sci-hub was founded by Kazakh graduate student Alexandra Elbakyan in 2011, as a reaction to the high cost of research papers behind paywalls, typically US$30 each when bought on a per-paper basis.

Indeed. $30 is the price of three hard-cover books in Russia or Kazakhstan

10:16 AM

@CowperKettle is it illegal?

user116211

@DHMO No.

quite brave of her/him

@MAFIA36790 :o why

user116211

I mean there are some legal problems too.

The prices on articles are outlandish, they are just something out of fantasy world

user116211

@DHMO The site is not illegal.

10:18 AM

@MAFIA36790 then why hide?

Do the authors of the articles really receive the 30 bucks if someone pays for the article?

user116211

Sci-Hub is an online search engine with over 58,000,000 academic papers and articles available for direct download, bypassing publisher paywalls. New papers are uploaded daily when accessed through educational institution proxies, and papers that have been accessed through Sci-Hub are stored in the LibGen repository. Sci-hub was founded by Kazakh graduate student Alexandra Elbakyan in 2011, as a reaction to the high cost of research papers behind paywalls, typically US$30 each when bought on a per-paper basis. Sci-Hub follows the general open access movement of the 1990s, and a number of smaller...

savage

> In her defense Alexandra Elbakyan has cited Article 27 (1.) of the UN Declaration of Human Rights "to share in scientific advancement and its benefits", which she claims is hindered by publishers demanding payment despite putting in minimal effort in publishing the academic papers, which she says are essentially donated by researchers.

Let them charge, say, 1 dollar per paper, and then people will use Sci-Hub less.

user116211

Sci-Hub is quite popular in India.

10:22 AM

Here, everyone uses it

Prior to that, I used to ask my friends to download this or that paper

I'm drawing the MO of N2 without any knowledge of SALC lol

user image

@Wildcat I understand what you mean now

@Wildcat can you comment on my MO diagram?

11:08 AM

> In reducing conditions, the disulfide bonds are removed, which allows the polypeptide chains to adopt a uniform stretched-out conformation and permits the precise determination of the molecular weight by assessment of the protein's electrophoretic mobility. (I don't like my phrase stretched-out conformation)

11:22 AM

@DHMO give me a second :)

btw, I've just made an attempt to answer the electronegativity question :)

@DHMO hmmm... you hybridized N AOs...

This is quite unconventional. :D

11:37 AM

@Wildcat VBT

@DHMO does not matter

besides, it is not VBT

it is clearly MOT

you're drawing a MO diagram

my point was

why do you introduce hybridization for N atoms?

@Wildcat VBT•MOT

hybridization of theories

@Wildcat hey, it was you who say that vbo is used with mot

Martin - マーチン

@Wildcat why not?

because 2s influences the sigma bond anyway

11:53 AM

@Martin-マーチン I didn't say it is wrong

I just asked what for?

What could not be explained w/o hybridization?

I mean, in this particular case of N2 molecule.

Martin - マーチン

lol...

@DHMO VBO is used alongside with MOT, in parallel

Martin - マーチン

you don't need hybridisation at all...

Two theories aren't mixed, but one can borrow concepts (such as hybridization) from another.

@Martin-マーチン I know that! :D

I wonder how погрешность метода is translated ...

Martin - マーチン

11:56 AM

@Wildcat You know that!

> Taking into account the error of the method, the obtained results comply with the theoretically calculated molecular weights of the light and heavy chains of the antibody. ("error of the method"?)

@CowperKettle probably, it is about accuracy

Taking into account the accuracy of the method ...

Sounds about right.

@Wildcat Thank you! It's "inversion", a known maneuver in technical translation. Probably it is indeed "precision" or "accuracy level" in English, instead of "error" as in Russian

12:09 PM

@Wildcat because you would mix 2s even if u use regular MOT

so i figured, why not mix it beforehand?

@DHMO you could

that is perfectly leagel

sure

now, what is the experimentally determined mixing ratio?

there is only one problem: many teachers can easily consider your approach "incorrect", since it is not what it is written in a textbook XD

then you'll likely get the bad mark :D

@Wildcat i give no heed to textbooks

@DHMO I don't think you can determine it experimentally

If only you consider quantum chemical calculations to be computational experiments...

12:13 PM

@Wildcat are they not?

@DHMO well, they are :)

@Wildcat exactly

@Wildcat do you know of any molecule whose MOs have been experimentally determined?

pentavalentcarbon

@Martin-マーチン No, and it should go under software and that alone.

No as in it shouldn't be deleted.

Martin - マーチン

@pentavalentcarbon so yes on overthinking the policy?

pentavalentcarbon

@Martin-マーチン The software policy is unclear, so it should be revisited.

Martin - マーチン

12:21 PM

okay. i think we can do that after the elections

@DHMO here's an experiment on BP86/def2-svp...

     (Occupancy)   Bond orbital / Coefficients / Hybrids
 ------------------ Lewis ------------------------------------------------------
   1. (0.99999) CR ( 1) N  1            s(100.00%)
                                         1.0000  0.0000  0.0000  0.0000  0.0000
                                         0.0000  0.0000  0.0000  0.0000  0.0000
                                         0.0000  0.0000  0.0000  0.0000
   2. (0.99999) CR ( 1) N  2            s(100.00%)
                                         1.0000  0.0000  0.0000  0.0000  0.0000

So, it is $\mathrm{sp^{1.65}}$ hybridization. XD

At HF/3-21G I got $\mathrm{sp^{1.51}}$.

Martin - マーチン

according to nbo

Well, s orbitals certainly contribute into the bonding MO.

pentavalentcarbon

@Martin-マーチン I started writing things about about this tag and these posts, but haven't gotten around to finishing it due to their low volume. I can finish it after the election.

Martin - マーチン

wow that's great

12:26 PM

Is the very last letter in @pentavalentcarbon's name missing only for me here in chat? :O

pentavalentcarbon

@Wildcat You must have eaten it.

I only see "pentavalentca" on the sidebar.

@Martin-マーチン what is BP86...?

Martin - マーチン

@Wildcat that depends on how wide your screen is

@DHMO it is an acronym :D

@Martin-マーチン this is the first time I noticed it!

@pentavalentcarbon that was not me! s-media-cache-ak0.pinimg.com/236x/36/84/0b/…

Martin - マーチン

there are not too many with such long names ;)

12:30 PM

@Wildcat what does everything mean?

Martin - マーチン

i noticed it when i put the chat in a small window

then all names get abbreviated

pentavalentcarbon

user image

@DHMO It is an electronic structure method that allows one to calculate the molecular orbitals of a molecule.

@pentavalentcarbon this looks (photo)shopped!

pentavalentcarbon

@Wildcat huh, and really poorly, too.

@pentavalentcarbon which molecule?

12:32 PM

@DHMO ANY MOLECULE! :)

pentavalentcarbon

@DHMO Any molecule.

grrrrrr

Even @Rubisco MOs can be calculated with that! XD

IN PRINCIPLE. XD

pentavalentcarbon

@Wildcat I just looked it up and it's thousands of residues. Maybe in a few years we can think about it.

Martin - マーチン

not in practice

@pentavalentcarbon yeah, it is a big molecule :D

12:35 PM

user image

:D

pentavalentcarbon

they look so fluffy

Ok. Once I find the time to do it (this evening) I will nominate myself for a mod position.

1:09 PM

@Martin-マーチン did i see d orbital?

@Jan I'm talking about things like the hypothetical CH4-CH2

CH4-CH2 + H2O -> CH3-CH3 + H2O

1 hour later…

2:19 PM

user image

I'm probably missing something, but how to show mathematically that it is 1:3 ratio, the cation:anion stoichiometric ratio?

2:42 PM

Heh, do you think I can type Maxwell-Boltzmann derivation in 30 mins? :D

@orthocresol depends on the quality

Nah, I don't think so. Simply typesetting the equations takes 30 minutes already

Now, look at one single octahedron.

There is one ion, in the middle of each octahedron.

And there are six counterions at the vertices.

But every vertex is shared between two octahedra, so effectively, one octahedron only has 6/2 = 3 of such ions.

Therefore, MX3 ratio.

@orthocresol i must be an idiot, thanks

The more interesting question, is what has that structure.

WO3?

@orthocresol AlF3

2:48 PM

well, I think I am correct too. WO3 has that structure as well.

:D

I see

@orthocresol Is quartz a polymer?

Dunno about the structure of quartz, but I don't think so.

I wouldn't say so. Polymer implies that there is a well-defined monomer

And there isn't one here.

thanks

because a textbook claims that it is a polymer

@orthocresol what about crystals?

What about them?

Are they polymers?

2:54 PM

Um... don't know.. I wouldn't call them that personally. But I don't know anything about polymers anyway.

alright

@Jan Maybe

@MAFIA36790 Wow, since it's discussed in h-bar, it must be right!

</sarcasm>, in case it's not obvious

Ok, bye guys.

Have a good evening.

\o

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The Periodic Table

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