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user228700
3:41 AM
Hello :-) I have a small doubt, can anybody clear it for me? I was wondering what it really means when we indicate that some compound has a net charge on it, as in the case of (-ClO4)
 
5:27 AM
@orthocresol ahh wish I had that sigh..
 
5:43 AM
"...this question will be closed. Please read our homework policy for more details. Welcome to ChemistrySE"
Sums up the vast majority of welcome posts LOL
@KaumudiHarikumar it means that this group of atoms has one more electron than they would otherwise have in the ground state
 
user228700
@ringo OK, thank you :-)
 
:) no problem
 
user116211
@orthocresol hmm; this has been asked before ;/
 
user116211
after you changed that.
 
6:00 AM
@ringo sad but true
I guess that's why some people might not find us that welcoming..lol
 
Yes, but we're trying to get better meta.chemistry.stackexchange.com/questions/3302/…
:)
 
Must be exam season or something? I saw like a fair bunch of hw posts today
Yeah, I know about deads experiment..neat idea
 
Yes, it is about that time of year
The saddest thing is that we're almost dead without them
 
oh really? Never knew we needed them haha
 
We don't, it just gets really slow without them
Nothing to answer, nothing to close
Of course they can sometimes bring new interested users as well though
Summers tend to be pretty slow
 
user116211
6:07 AM
Same thing has been asked 19 days ago at Phys.SE:
 
user116211
1
Q: Why must $\left(\frac{\partial U}{\partial V}\right)_{T}=0$ for an Ideal Gas?

BLAZEFrom the ideal gas (eqn of state) $$V=\frac{NK_BT}{P}\tag{1}$$ Where $P$ is the absolute pressure of the gas, $N$ is the number of molecules in the given volume $V$, $K_B$ is the Boltzmann constant, and $T$ is the absolute (thermodynamic) temperature. The general equation for the internal energ...

 
user116211
OP should have checked both the sites before asking at the first place.
 
Blech... all that latex in the title
 
user116211
@ringo Common practice in Phys.
 
Haha I'd imagine so...
 
user116211
6:10 AM
@ringo We, as editors, are not bothered with that at all. I was surprised to see otherwise in Chem ;)
 
We do it to encourage traffic to the site, because it impedes searchability
Maybe it's just because we're pretty small, relatively
 
@ringo I see. Guess I never noticed because I don't spend a lot of time on here lol
 
If you stick around you'll see it too
 
@MAFIA36790 was it the same person?
Oh no different..?
 
user116211
@getafix Not a cross-post for sure.
 
6:17 AM
Ahh yeah got it now
For a moment I thought it was
 
So @getafix, what year are you?
 
Just finished second year of undergrad, gonna start third this fall
Don't tell me you're an undergrad too? I was quite shocked to learn o-cresol was one haha
 
user228700
6:34 AM
@ringo I also have a follow up question. In a given oxidizing compound, is it true that it is always the central atom that functions as the "oxidizing element"?
 
user228700
Can anybody else answer this question please?
 
No
 
I am, starting my third year as well
 
Eg. Quinones are involved in redox processes in biochem and I don't even know what a central atom would be in that case
@ringo et tu..you guys are making me feel bad about myself lol
 
I was almost a ChemE--studying chemistry instead
Haha I don't know nearly as much as I might seem to
 
6:42 AM
i am Chem E but my Chem E is not really a Chem E because I decided to skip all but the bare essential Engg electives
Studied a lot of math and phy for fun though..
 
Oooooo
 
Where do you go to school?
 
UT Austin
 
Oh nice..
 
I can appreciate a chem e who is really into the chemistry. Not many (that I know personally) really seem to be
Where do you go?
 
6:44 AM
Oh hahaha yeah, I don't really know why I opted for Engg degree.. Chem is my first love lol
Nagoya Uni, in Japan
 
No kidding......
 
user116211
@ringo what is ChemE?
 
Chemical Engineering
 
Speaking of don't know if you planned it that way..your pic is that of an apple and your name is ringo which is apple in Japanese
Yeah not kidding haha
 
user116211
@ringo ohh, what is it related to?
 
6:45 AM
It is planned that way ;)
 
Ahh excellent good job then
 
user116211
How is it different from chemistry?
 
user116211
@ringo Great!
 
日本語を勉強しました
but I gave up a while ago
 
偉い偉い
 
6:48 AM
My understanding is that it's more math and less chemistry
 
My Japanese is embarrassingly bad..I studied it for a year when I first got here then gave up choosing to focus on my actual academic courses
 
and designing systems to run reactions(?)
 
user116211
Go on, go on; with Japanese, make the room the next G-block Elements; Mart would be proud.
 
user228700
@getafix Did u mean "No, can't answer"?
 
Yeah that would mostly be it..I think ..like I said, I am not doing an lot engineering electives
 
6:50 AM
@MAFIA36790 afraid I don't know enough to do that lol
 
No my answer was no..
 
So you're on exchange then?
 
Nope 4 year degree
 
Wow! Where are you originally from?
 
India
 
user228700
6:51 AM
@getafix Oh! Okay. Do you know any examples?
 
I just gave you one ..go back and check
 
すごい
What's your native tongue?
 
I'm in the G30 program, don't know if you know about it..
English and Hindi I would say
 
user228700
@getafix Oh, yes. Thanks!
 
Cool! One of my flatmates speaks Hindi
 
6:53 AM
Oh cool..Indian?
 
Mhm
Kya hua... it's all I know
LOL
 
user116211
@getafix Are you from the Indian sub-continent?
 
Hahaha Lolol
@MAFIA36790 not just the sub continent ..I'm actually Indian lol
 
user228700
It isn't surprising that there a lot of Indian nerds on this website :-)
 
user116211
@getafix okay... hey what? Indian!!!!
 
6:56 AM
You too I gather?
I should properly learn Japanese before I graduate..sigh
It would be such a wasted opportunity otherwise
 
Do you not hear it everywhere you go?
 
I am quite aloof lol but yeah I do which is why my listening is not that bad..my speaking/writing and especially my kanji are shit
I can understand conversations but not participate in them it is weird lol
 
Interesting
 
Yeah lol
 
I'm fairly proficient in Spanish, I'm just mostly too nervous about looking stupid in front of native speakers
I should get over it though
 
7:09 AM
Haha yeah you should to be honest, that's why my Japanese did not get that good lol I did not practice enough with native speakers..mostly fearing embarrassment if I make mistakes
 
Well let's both resolve to practice:)
 
Indeed. Let's
Hmm can't find any questions I feel like answering
 
7:31 AM
Pro tip answer boring questions and get the tenacious badge
 
user116211
@getafix Well, hmm, this happens; lot of my time is spent reading other's posts on my recent topic of study and editing the posts. Although I answered a question today.
 
user116211
Of course in Phys.SE.
 
7:42 AM
I'm so close to the copy editor and archaeologist badges
I was working on archaeologist for a while before people started getting mad that I was resurfacing so many old posts
 
8:03 AM
I'm close to the civil duty badge ..feel like just going out there and casting a bunch till I use up my daily allowance
 
 
4 hours later…
11:45 AM
I have an idea: let's answer the unanswered questions from the oldest
 
12:41 PM
@orthocresol Is this "reaction" exothermic? 2CH4 -> (CH4)2
main chain: H-C-H-H-C-H
 
@user34388 is that even possible?
 
@getafix no, hence the quotation mark
 
Oh okay
Missed that
You can do a quick back of the envelope calculation with bond diss energies
 
@getafix is there any bond broken?
 
Oh wait..I misread your question yet again
So it's basically two methane linked via hydrogen hydrogen bond?
 
12:50 PM
@getafix yes
 
Good evening!
 
Ah I thought what you put down as main chain was the final product
 
> We used reversed-phase HPLC to analyze the aspartyl forms of the antibody (Is this a proper expression?)
 
@CowperKettle Maybe you would like to have a look at my theoretical question
 
Good evening kettle
 
12:51 PM
@getafix my apologies
 
Nah none necessary I'm just tired lol
 
@user34388 Where is it?
 
> Is this "reaction" exothermic? 2CH4 -> (CH4)2
H-C(H)(H)-H-H-C(H)(H)-H
 
@user34388 No idea, sorry.. By the way, what is (CH4)2?
 
@CowperKettle two methanes linked via hydrogen-hydrogen bond
 
12:53 PM
So diff between the bond energies of product and reactant is the bond diss energy of just H-H..
 
@getafix which means yes?
 
Going by that yes
 
but why is that reaction impossible?
 
Because the electron on both hydrogen part of the ridge is already taking part in the carbon hydrogen bond
 
@getafix electrons are not localized
@Loong You might be interested in this
 
1:02 PM
what is the difference between isoaspartyl and isoaspartate?
 
@CowperKettle -yl is -ate minus the O
so acetate is CH3COO^-
acetyl is CH3CO* (radical)
 
When aspartate is part of a protein, it is always "aspartyl"?
If I have a monoclonal antibody in which asparagines deamidinated, will they become "aspartyls"?
 
@CowperKettle I don't think the peptide bond is related to the carboxylic group in the side chain
 
@user34388 But does not the C-terminus include the carboxyl group?
So an isoaspartate on a deamidated antibody will be "isoaspartate", and not "isoaspartyl"?
The isoaspartate group is a functional group in biochemistry. Its formation is a chemical reaction in which the side chain of an asparagine or aspartic acid residue attacks the following peptide group (in black at top right of Figure 1), forming a symmetric succinimide intermediate (in red). The symmetry of the intermediate results in two products of its hydrolysis, either aspartate (in black at left) or in iso(Asp), which is a β-amino acid (in green at bottom right). The reaction also results in the deamidation of the asparagine residue. == Kinetics of isoaspartyl formation == Isoasparty...
This page uses both words, and I don't understand.
But my Russian text for some reason says "analysis of isoaspartyl forms.
 
@user34388 I know that..but electron density exists b/w C-H if we are to form the H-H bond then the C-H bond must break..hydrogen just has the one electron
 
1:11 PM
@getafix what causes it to break? why does it favour breaking?
 
I give up..
 
@CowperKettle O biochemistry, why must you be so complicated?
 
So deamidation produces isoaspartate or isoaspartyl? The Wiki page is unclear
 
It doesn't hence your compound doesn't form
 
@CowperKettle deamidation of what?
 
1:14 PM
@user34388 of asparagine
 
@getafix it doesn't what?
 
it doesn't break
 
@getafix I thought it breaks immediately
 
As far as I know methane doesn't dimerise like that
 
it was hypothetical
because I heard the claim "all bond-forming processes are exothermic"
 
1:16 PM
What I mean by that is there can be no bond forming in such a case
There's simply not enough electrons to go around
 
@getafix so it is a tautoloogy?
 
Is the green thing "isoaspartyl"?
Or do we need to take away one O from COOH to make it "aspartyl"?
 
@CowperKettle The problem is, there is two carbonyl groups
so it contains both -ate and -yl
 
Yeah the way I see it
 
which one is it referring to?
 
1:20 PM
@user34388 Isn't there four carbonyl groups?
 
@getafix but look at the second section of the wiki page
 
what wiki?
 
@CowperKettle the other two belong to other amino acid residues of the peptide chain
 
@user34388 Even the right one?
It seems to have NH as its R and CH2 as its other R
@getafix this page calls it first "isoaspartate" then "isoaspartyl". O_O
 
Ah! Typical biochem people...Also, your question got me interested so I'm doing some more reading.
But as far as I know, a covalent bond like you depict is unlikely
 
1:24 PM
@CowperKettle
 
@getafix I'm glad it made you interested! I thought I was just being chem-stupid
@user34388 Yes, they are a bit different, but it's not very clear to me (0:
 
@CowperKettle Wait, the division doesn't seem right...
 
How is that "Unclear what you are asking"?
-1
Q: Molecular structure of all periodic table element molecules exceptional cases etc

ThampuranI am searching about some basics in chemistry. I was looking for the molecular structure of all periodic table element molecules. eg: Hydrogen molecule: as $\ce{H2}$; structure: I was able to find out several others too. But when I reach to certain molecules like $\ce{He}$ I was not able to find...

 
@CowperKettle Never mind, my division is right
so as you see, there are only two carbonyl groups
 
@user34388 you should ask Martin your question..
 
1:29 PM
@Martin-マーチン Could I ask you a question?
 
@user34388 sure
 
@Martin-マーチン Are all bond-forming processes exothermic?
 
@user34388 no the more interesting methane dimer you were talking about.. haha
 
@user34388 hang on.... iirc we have a question on that
 
@getafix lol
 
user116211
1:31 PM
Hey @martin! How you doin'? Nice to see you :)
 
6
Q: Is Bond Formation "Strictly" Exothermic?

DissenterIs bond formation "strictly" exothermic? The IUPAC definition of exothermic doesn't make any reference to bond formation. However, I have seen the aforementioned statement before - that bond formation is "strictly" exothermic. I suspect that the answer is "it depends" and that "it depends" at l...

 
@user34388 No for real, I think he can give you better insight...
 
@MAFIA36790 o/
 
user116211
\o
 
And where are my manners.. @Martin-マーチン o/ How goes?
 
1:32 PM
;)
Okidoki so far
 
@Martin-マーチン contradictions everywhere
inconsistencies
Welche Antwort ist richtig?
> The energy to dissociate HHeF to H + He + F is negative.

The energy to dissociate HNeF to H + Ne + F is negative.
 
well, that is a bit tricky
 
@user34388 Correction: -yl is -ate minus the H
 
@CowperKettle but acetyl is CH3CO* and acetate is CH3COO^- ...
 
@Martin-マーチン , user34388 had a question originally about a covalently linked CH4 dimer..in my mind, that seems pretty impossible. But anyway, it got me interested, and I dug up the study i just linked to.. pretty neat stuff imo..it discusses C-H---H-C weak interactions, and predicts dissassociation energies as high as 12 kj /mol much higher than what i wouldve guessed..care to weigh in?
 
1:40 PM
@user34388 I looked up IUPAC rules, and it says: "The names of the substituents formed by the removal of one hydrogen from the end of the chain is obtained by changing the suffix -ane to -yl."
 
I am curious as to what you would have to say.. haha
 
@CowperKettle that's for -ane to -yl
like ethane (CH3CH3) to ethyl (CH3CH2*)
 
Acetyl is an "acyl"?
An acyl group (/ˈæsɪl/ or /ˈeɪsaɪl/) is a functional group derived by the removal of one or more hydroxyl groups from an oxoacid, including inorganic acids. It contains a double bonded oxygen atom and an alkyl group. In organic chemistry, the acyl group (IUPAC name: alkanoyl) is usually derived from a carboxylic acid. Therefore, it has the formula RCO–, where R represents an alkyl group that is linked to the carbon atom of the group by a single bond. Although the term is almost always applied to organic compounds, acyl groups can in principle be derived from other types of acids such as sulfonic...
 
@CowperKettle yes, radical of acid
 
So it must be isoaspartate residue and never isoaspartyl
 
1:43 PM
@getafix I don't have access to the article, but it sounds really fascinating
 
The Wikipedia page should be fixed then (0:
 
@CowperKettle let's say you have oxalic acid
HOOCCOOH
 
@Martin-マーチン Skimmed through it real quick, seems that way..but well I'm no expert haha Plan to read it at leisure tomorrow morning
 
oxalate would be -OOCCOO-
oxalyl would be *OCCO*
what would -OOCCO* be?
 
@user34388 isooxalyl?
 
1:45 PM
@CowperKettle that's not how you use iso-...
@Martin-マーチン Is my answer good enough now?
 
I don't get this at all now. The asparagine's termini were not changed by diamidation.
Where is the "yl" there then?
Oxalyl chloride is a chemical compound with the formula (COCl)2. This colourless, sharp-smelling liquid, the diacid chloride of oxalic acid, is a useful reagent in organic synthesis. It can be prepared by treating oxalic acid with phosphorus pentachloride. == Reactions == Oxalyl chloride reacts with water giving off gaseous products only: hydrogen chloride (HCl), carbon dioxide (CO 2), and carbon monoxide (CO). (COCl)2 + H 2O → 2 HCl + CO 2 + CO In this, it is quite different from other acyl chlorides which hydrolyze with formation of hydrogen chloride and the original carboxylic acid. ...
Here I see where the "yl" is
The oxygens were replaced by Clorides
 
0
Q: How to grow Genus Bacillus at home in high concentrations

Gary McNeishI need to get a high concentration of Genus Bacillus. Can I do this at home?

 
But in asparagine, the C and the N termini remained the same
 
Don't think this belongs here on Chem.SE
Plus, I think it is a poor question..
 
@CowperKettle it would not be the same in asparagine residue
by the way the -ate in aspartate never referred to the terminal
 
1:52 PM
@user34388 It's better, but it's really recommended that you use the upload functionality in the editor. This way it is ensured, that the pictures remain on the site. We have had loads of troubles with images in nice answers that were suddenly gone and no-one was able to find them again... that's a bad thing when it happens.
 
but I have no idea what the -ate in isoaspartate refers to
 
so "isoaspartic acid" is always "isoaspartyl"?
 
@Martin-マーチン ok, a minute
@CowperKettle no, i was talking about aspartic acid
the "acid" never referred to the C terminal
 
I do not understand why that Wikipedia page uses "isoaspartate" and "isoaspartyl" without explaining the difference, as if it is one thing
 
@user34388 It's really just well-meant advice, because if we do it right the first time, it saves us all a lot of time later. Thank you very much for taking care of that :D
 
1:54 PM
@CowperKettle As I said, I have no idea what the -ate in isoaspartate refers to
it is strictly an amino acid but it is not bonded like one
 
So to obtain an "isoaspartyl" we need to cut one H from the OH in the middle of isoaspartate? O_O
 
@CowperKettle As I said, I have no idea what the -ate in isoaspartate refers to
 
Oh, shucks, I'd better translate it as it is, it's impossible to understand. (0:
 
@Martin-マーチン better?
 
:D Thanks a lot
 
2:02 PM
0
A: Dimers and polymers of electron deficient compounds

user34388First of all, you have it all backwards. You sound like the $\ce{AlCl3}$ says, "Oh, I am in solid state now! Let me turn to crystal (polymer) structure! [a while later] Oh, I am in vapour state now! Let me turn to dimer structure!" Where in reality it says, "I don't have enough kinetic energy t...

@Martin-マーチン please review this?
 
@user34388 Anyway, big thanks for your answers!
0
Q: Difference between "isoaspartyl" and "isoaspartate" in antibody deamidation

CopperKettleI'm translating a where antibody deamidation is mentioned. One sentence goes like this: We used reversed-phase HPLC to analyze the aspartyl forms of the monoclonal antibody. (Russian original text: "изоаспартильные формы") However, in scientific papers the word is "isoaspartate", not "isoa...

I have points to spare, in case it gets downvoted. (0:
 
@CowperKettle I really can't find properties of "isoaspartate"... is it a made-up word?
 
2:34 PM
A little learning is a dangerous thing; drink deep, or taste not the Pierian spring...
 
@orthocresol Pope clearly was not prepared to be a translator, or he would have died of overdrinking.
And the Pierian spring was much more shallow in his time.
 
2:52 PM
0
A: How can FeS2 be the formula of iron sulphide and CaC2 be the formula of calcium carbide?

user34388Calcium carbide is $\ce{CaC2}$ because the anion is a slightly more complicated $\ce{C2^2-}$ instead of the naively expected $\ce{C^4-}$. The anion of $\ce{FeS2}$ is also the more complicated $\ce{S_2^2-}$ instead of the expected $\ce{S^2-}$. Notice that the simple $\ce{FeS}$ whose anion is $\c...

Why the downvote?
 
 
8 hours later…
11:04 PM
@orthocresol must be a troll
Looks like one of the better askers of quantum chemistry questions deleted their account. A sad day.
 

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