The Periodic Table

getafix

12:38 AM

@orthocresol sound advice...but I do want to graduate so, dont think I can go around ignoring the real world haha

although while on the subject, i hate the ask and run types..never bother to up vote/accept

user116211

3:21 AM

2

Q: Does the Dirac equation ever get used in Physical Chemistry?

I'm just curious as to know if there are any examples in physical chemistry or condensed matter physics where the Dirac equation is preferable to the Shrodinger equation for making predictions on the material at hand?

orthocresol

5:19 AM

@Mithoron I think it dupehammers questions when the asker agrees that it is a duplicate but there aren't enough CVs yet. At least that's what happened once.

648

Q: Six simple tips to get reputation fast on any Stack Exchange site

An article, "6 Simple Tips to Get Stackoverflow Reputation Fast" at codexon.com, made these suggestions: Be the First to Answer. Even at the cost of quality. Use Downvotes and Comments Strategically Use obnoxious in-your-face formatting and lists. Be Aware of the 200 rep/day Limit ...

discussion reputation article strategy

user161117

Hey does anyone on this site know how to not ruin it and scare everyone away with their bad attitude or what? lol

user161117

Well, when the squad returns, I want you guys to think of this as your wake up call. You're really scraping so hard to get people to join that you've started trying to answer homework questions!

user161117

pull yourselves outta denial, you're making chemistry look bad, OK

user161117

I hate to be the one to tell ya this, I really do. Thanks

user116211

@StevenGrigsby What?

user161117

5:28 AM

Make CSE great (again?)

user116211

@StevenGrigsby okay...?

user161117

You're probably fine, I haven't seen much of you around

user116211

@StevenGrigsby :(

user161117

Just really scraping to find some good quality, reliable content around here

user116211

@StevenGrigsby Anyways, what's about the homework stuff that is bothering you?

user161117

5:30 AM

Haha nothing, you misunderstand

user116211

okay, then.

user161117

:'(

user116211

@StevenGrigsby BTW, I'm the great MAFIA!

getafix

6:20 AM

@StevenGrigsby what do you mean?

@orthocresol oh nice. thanks

orthocresol

6:50 AM

@StevenGrigsby How about, for a start, being civil?

Do you know what equilibrium constants are? — Kainui 2 days ago

I hate to be the one to tell you this, but that comment makes you come off as a huge jerk.

getafix

Hahaha

getafix

9:42 AM

@orthocresol Guess both of tried to add the spoiler tag at the same time..

that's why my edit didnt take

also just realised my current rep is 1984..the little orwell fan inside of me is happy

user116211

@getafix why that ;)

getafix

haha why what?

I wonder where the trump-esque troll disappeared? the make cse great again guy..

user116211

@getafix That was an iconic movie!!

user116211

It still chills my spine!

user116211

@getafix Who? Well, nevermind.

getafix

9:51 AM

@MAFIA36790 Havent seen the movie..just a fan of the book by george orwell

Steven some guy..

user116211

@getafix oh... sure. That is amazing.

getafix

yup indeed

orthocresol

10:17 AM

@getafix heh... oops. go and edit 8 more posts, then you don't have to clog up the edit queue :)

start with this one: chemistry.stackexchange.com/questions/59329/… add the reference-request tag haha

once you learn the joys of editing, you will never leave this website again

note that joys of editing do not include typing out the Laplacian in spherical coordinates

chemistry.stackexchange.com/questions/10827/… he could have just used $\nabla^2$ and that would be much easier..

getafix

10:39 AM

@orthocresol not that I mind editing 8 more posts..but what is this about me clogging up an "edit queue"? I know of no such thing haha..

oh is it the "peer review" message that I see ?

Mithoron

10:56 AM

@getafix If you'll get 2k rep you won't

getafix

11:13 AM

ah I see.

getafix

11:28 AM

soon..very soon..*menacingly rubs hands together*

orthocresol

11:45 AM

it never ends... next you will have to get 3k in order to close questions..

getafix

Haha fair enough.

made it!

orthocresol

just promise me, don't get 10k, it's not worth it

getafix

lol dont think i'll be able to

at least not for a while

orthocresol

it takes quite a while even if you are super active..

chem is a relatively small site

getafix

yeah..there's what like 20 people over 10k?

orthocresol

11:52 AM

16 currently, but bon will probably reach 10k soon

getafix

ah I see..

yeah took me over a year to get to 2000, so dont see myself getting to 10k anytime soon

orthocresol

check back in the year 2021 :)

actually, 2020... maths fail

Mithoron

Site is getting bigger so rep progresses should generally accelerate

getafix

Haha yeah lol

Mithoron

BTW over 2k one can still get rep from tag wiki edits

orthocresol

12:01 PM

some of the tag wikis need serious rewriting

chemistry.stackexchange.com/tags/orbitals/info

orbital is a disaster right now

actually, say what, i think i'll rewrite that tonight

getafix

cool stuff..

so I can no longer gain rep from editing regular posts though?

Mithoron

Yeah it is :(

@getafix Should have edited more ;)

getafix

@Mithoron Should've haha

Mithoron

One can get up to 1k this way

getafix

Yeah I think I just managed to get 20 rep out of it lol

may have edited 10-12 posts tops

ah well too late..still happy about breaking it past 2k

ahh editing tag wikis seems like hard work..

Mithoron

12:14 PM

Excerpts count separately, and now you don't have any length limits ;)

getafix

perhaps I should aim to collect another 500 rep before school starts..dont think i'll have much time after that sigh.

effectively, i just end up spending a few months every now and then during semester break on here..

Why university education..why?

orthocresol

@getafix I can downvote all your posts, and then you make more edits :D

getafix

Umm lol..hahah

nah, I am good.

plus a downvote is a -2? so assuming I loose rep for each downvote and I gain by editing..wouldn't I just break even?

orthocresol

yeah, but after that i just re-upvote your questions

LOL

getafix

hmmm..

orthocresol

12:20 PM

that's gaming the system

getafix

haha yeah did not think about that..

Mithoron

And unupvote could make 10 there :D

CowperKettle

Good afternoon

getafix

i can't believe I am considering this..haha..

No..no...no..I should learn to be content.

Mithoron

:D

CowperKettle

12:23 PM

Is "carbohydrate residue" a good expression? (like "amino acid residue")

getafix

@CowperKettle Good afternoon

CowperKettle

I've got a sentence that goes like this:

> Carbohydrate residues constitute not more than 2–3% of the total mass of an immunoglobulin (Beck, 2008),

When I studied chem, I only read about amino acid residues

orthocresol

@CowperKettle never seen it, but it is quite clear to me what it means.

getafix

sounds fine to me..

CowperKettle

okay then (0:

getafix

12:25 PM

dont know if ive ever seen it before

orthocresol

immunoglobulin (an antibody) is a protein, so presumably it undergoes glycosidation and this addition of "carbohydrate residues" constitutes about 2-3% of the mass

getafix

12:38 PM

btw

what should i do with a question like this:

btw

7

Q: Silica turning transparent during column chromatography with chloroform

Initially, my column had been loaded with n-hexane and ethyl acetate, however I ended up having to use a more polar solvent to elute my product. It was my first time running chloroform through a column packed with silica and I noticed that as the chloroform made its way down the column, the silic...

analytical-chemistry chromatography

I guess I answered it myself when asking it?

orthocresol

i have no clue actually, i've never done a chcl3 column

getafix

Ivan's comment seems to suggest that I got it right..it's got a few up votes too.

orthocresol

i never figured out what is MC?

methyl chloride?

oh gosh i just figured it

it's methylene chloride...

i'm too young, and being in the UK, it's always been DCM to me.

getafix

DCM? that's the first I've heard of that term ol

orthocresol

...

getafix

12:47 PM

whereabouts in the UK..just curious..

orthocresol

oxford

getafix

Oh do you go there?

orthocresol

1:05 PM

mmhmm

getafix

oh cool~

I plan to apply for grad school..sigh..soon, very soon..

Interested in Prof. Harry Anderson's group..

orthocresol

1:21 PM

ah!

well, there isn't really much i can tell you about him

he's a nice guy, as far as i can tell

getafix

oh well that's good to know! :)

lol, I am currently extremely intimidated by the very thought of applying to grad school.

orthocresol

i still have two more years of undergrad haha

1,3-feeds

0

Q: Scope of orbital tag

The orbital tag wiki is currently quite a disaster. I hope you will agree if you read it. Just a few (of the many) complaints that I have: No reference to wavefunctions, which is precisely what an orbital is! Implication that filling all orbitals is stable, in which case everything should reall...

discussion tags

getafix

No way! You're an undergrad? :O

I assumed you were like a post doc or grad student haha

orthocresol

1:41 PM

nah, starting 3rd year in october

getafix

3:00 PM

@orthocresol Hi5! same

Loong

3:12 PM

@orthocresol Next try: I added a coloured picture to my answer. Let's see how that affects the result. ;-)

orthocresol

@Loong (-1) Images are not searchable. Please consider typing out the information so that future visitors can benefit.

Loong

:-(

But it has colours!

orthocresol

@getafix But here we do four years leading to a Masters, the fourth year being full-time research. So still a while more until PhD :)

@Loong We'll see ^^

Loong

Obviously, colours increase the truth of a graph!

And for the best possible reputation yield, I should remove the ugly text from my answers. ;-)

CowperKettle

> Deamidation is a post-translational modification in which an asparagine or a glutamine amino acid residue of a protein loses an amino group (Isn't this an error?)

The Russian text has it as "amino group", but Wikipedia says it's amide group

orthocresol

3:27 PM

the amide is hydrolysed

i don't know what that counts as

Loong

Deamidation

Deamidation is a chemical reaction in which an amide functional group is removed from an organic compound. In biochemistry, the reaction is important in the degradation of proteins because it damages the amide-containing side chains of the amino acids asparagine and glutamine. In the biochemical deamidation reaction, the side chain of an asparagine attacks the following peptide group (in black at top right of Figure), 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 isoaspartate...

CowperKettle

I've just been on that Wiki page. I can't understand what exacly is taken away from the article's Figure

I see a new amide appearing on Asparagine

At the top of the molecule

Isn't an "amino group" really a small part of an "amide group"?

Good evening, by the way, Ortho, Loong!

The full sentence goes like this:

> Deamidation is a post-translational modification in which an asparagine or glutamine amino acid residue of a protein loses an amide group and transforms into an asparagine/isoaspartate residue or a glutamate residue respectively. (I took the liberty of making it "amide", not "amino" group, as in the original text)

orthocresol

biochem is usually a bit lax with terminology

Loong

@CowperKettle I guess, I wouldn't say "an amino functional group is lost"; I would say "an amide functional group is hydrolyzed".

orthocresol

CowperKettle

3:36 PM

@Loong Thank you! I'll try to see "hydrolysis" on the picture I uploaded

I wonder what those wavy lines are on the picture

orthocresol

they just represent connections to other amino acid residues

CowperKettle

When those residues are connected to each other, they don't have COOH?

found it

I read that in the spring, and managed to forget

N-terminal and C-terminal remain, but at the very ends of the protein

> Deamidation is a chemical reaction in which an amide functional group is removed from an organic compound. (Wikipedia says "removed", not "hydrolyzed")

I misenterpreted the Figure. The reaction starts in the top right corner.

> Deamidation is a post-translational modification in which an asparagine or glutamine residue of a protein loses an amide group and transforms into an aspartate/isoaspartate residue or a glutamate residue respectively.

This is better

But it does lose one nitrogen atom.

Since it is lost, we can say that the amide group is "removed" probably

> The process is non-enzymatic and goes faster at basic pH or if there is a glycine residue C-terminal-wise from the asparagine.

There must be a better formulation. (0:

> The process is non-enzymatic and goes faster at basic pH or if there is a glycine residue between the asparagine and the C-terminus.

no.

> The process is non-enzymatic and goes faster at basic pH or if there is a glycine residue connected to the asparagine's C-terminal end.

I'm not sure if this is right, since the asparagine's residue would not have the C-terminal end if there's glycine connected to that.

> Deamidation proceeds much more quickly if the susceptible amino acid is followed by a small, flexible residue such as glycine whose low steric hindrance leaves the peptide group open for attack

Found it: the term is C-flanking

> Iso-Asp forms most easily in sequences where the side chain of the C-flanking amino acid is relatively small and hydrophilic, and is less likely to be formed where bulky or hydrophobic residues are in this position. The most favorable for Asp-isomerization C-flanking amino acids are Gly, Ser, and His

I hope I did not clutter the chat too much

CowperKettle

4:21 PM

@MAFIA36790 I do hope he returns at least for a short visit.

orthocresol

5:15 PM

1

Q: Thermodynamics of ideal gas - partial derivatives

What are the following partial derivatives equal to? The quantities describe an ideal gas state. $$\left(\frac{\partial U}{\partial T}\right)_{\!V} \\ \left(\frac{\partial H}{\partial T}\right)_{\!P} \\ \left(\frac{\partial S}{\partial T}\right)_{\!P} \\ \left(\frac{\partial U}{\partial V}\right...

physical-chemistry thermodynamics

should I split this up?

"Why is (dU/dV)T = 0 for an ideal gas?"

user116211

@CowperKettle sure; maybe he is taking his exams.

user116211

@orthocresol Ah! They are turned to mathjax! relieved.

orthocresol

@MAFIA36790 I don't want to type out a mathjax-heavy answer for a question that doesn't really focus on one topic

yeah, I changed them

user116211

@orthocresol yeh, thanks for that ;)

user116211

@orthocresol Yes, definitely.

orthocresol

5:26 PM

I guess I will steal the rep from him then.

poor marko, he can't catch a break here, what with all the homework and too broad

user116211

Anyways, I just got the classic Linear Algebra: Hoffman and Kunze delivered!!

user116211

The price?

user116211

Just 3 dollars!!

orthocresol

Nice

user116211

The US edition worths more than 70 bucks.

orthocresol

5:29 PM

Ouch...

user116211

@orthocresol yeh.

user116211

@orthocresol Indian Subcontinent editions are generally much cheaper than their US counterpart.

user116211

Sometimes the international price is insane.

user116211

Just for instance, this:

user116211

in The h Bar, yesterday, by Bernard Meurer

because Apostol is 300 USD in US amazon

user116211

5:34 PM

in The h Bar, yesterday, by Bernard Meurer

I ain't paying 300 bucks

user116211

in The h Bar, yesterday, by MAFIA36790

@BernardMeurer this actually costs 15 bucks here in India.

user116211

Although sometimes happen otherwise, but most of the time, the price here is quite lesser than the international equivalent price.

Loong

9:12 PM

physics.stackexchange.com/election/3

1,3-feeds

9:42 PM

0

Q: Why is this homework question still closed?

The question What mass of water is present as a liquid when equilibrium is established? clearly is a homework question. The homework tag has been added to the question within two minutes after it was posted. The first attempt of the author may be considered very weak: This is in the gases se...

discussion homework close-reasons specific-question

user34388

11:49 PM

If SF6 is ionic then why is it directional?

2. Does CsF really have some covalent character?

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