The Periodic Table

And the only person I know who ‘knows a pharmacist’ and uses that supplies the sauna with menthol for steam-throwing … and I hate menthol steam =C

I once had to ask for simple plaster strips in a Chinese pharmacy. I felt so silly. And they gave me the strips for free. :-)

Q: Hyphen escape in mhchem not working with bidi

12:54 AM

0

Typesetting my chemistry thesis using mhchem, I make semi-frequent use of the option to escape to text mode using {}, especially to typeset hyphens in the midst of chemistry like in the following way: \ce{6{-}Me}. The output should be: 6-Me However, after the addition of a word in Hebrew, t...

The problems one has to deal with when TeXing =C

Why, oh why did I choose to include a word of Hebrew in my thesis?

:-D

I'm just happy that I was able to send mine in for reviewing 4 hours ago

You deserve applause!

well thanks, now I just need one more committee member for the defense

@DSVA Haha, that (and the date) is the hardest part. ;-)

Reminds me I also still need a third.

Even though my second is already not an organochem professor, the third person also must not be organochem — or so I was told.

1:03 AM

I got the date:-D that's what makes finding a 3rd so difficult, especially since it has to be someone who's not from my faculty

There’s a reason why the secretary in charge of the thesis office is called final boss …

yeah at least I don't have those problems. my co-supervisor is vice rector for research at our university, once I drop his name everything is possible.

is this master or PhD you are doing?

PhD

ah nice

Melanie Shebel

2:08 AM

Why don't I ever see ads, aside from community ads, on the chemistry.SE?

How do they make money from chem.SE?

Hardly at all. SO being a programming site and what started it all and by far the hugest, that’s what’s making money.

CowperKettle

8:25 AM

Good morning!

> Place 1 ml of formic acid (assay ≥ 50 % Fluka Catalog No. XXXX or equivalent in quality) into a 1000 ml beaker.

What is the meaning of this bolded phrase?

12:16 PM

@MelanieShebel I have an archaeologist? O.O

Q: Why does milk overflow when boiled?

18

I was wondering that like whenever I boil milk I just have to keep standing in front of it to make sure that I don't waste any milk but then I was wondering like Why does it even overflow ? In case of water it doesn't happen. What makes it to behave like this ?

everyday-chemistry heat food-chemistry

Q: electrolysis of different solutions

1:10 PM

What should we do with this?

0

How can we find among the following solutions which remains neutral after electrolysis . $CuSO_4$ $AgNO_3$ $K_2$$SO_4$ $NaCl$ My try With (A) copper sulphate the copper comes out as copper metal so that doesn't change the pH, while at the other electrode the sulphate forms sulphuric acid. So...

electrochemistry

1:26 PM

Anyone happen to know why maltose is a reducing sugar but sucrose isn't, even though they're both disaccharides? [ Currently googling this up ]

2:27 PM

@Mart Is it possible to convert a room that was imported from a comment discussion, to a 'gallery'-type one?

3:01 PM

@pentavalentcarbon o/

Hey @Kaumudi o/ Apparently Koolman's suspended till December 20th or so XD [I'm not a sadist...but that guy was getting on my nerves ._.]

o/

@pentavalentcarbon So, how goes?

good, doing work, shouldn't be here...

I see ;)

@AaronAbraham Yes, the room owners (and all moderators) can do that, as far as I know.

user228700

3:19 PM

@AaronAbraham Oh, that sucks for him :-/ But yeah, he pinged everyone at once, so...

Zhe

@pentavalentcarbon This is work

3

Some of the review tasks do feel like it.

Once you get to 2k, looking at suggested edits is fun.

Martin - マーチン

@AaronAbraham Should be possible; the question is rather why or why not do this. Do you have trouble with a user there, then there might be a deeper problem at hand.

Zhe

@pentavalentcarbon 1842 and counting

Martin - マーチン

@AaronAbraham What happened? What has he done to unnerve you? Anything we (the mods) should know aabout?

Melanie Shebel

3:57 PM

I hope this site grows enough so that SO doesn't cut it if there isn't funding for it down the road!

4:12 PM

@Martin-マーチン You might laugh if I said I felt I was being stalked (Unrelated: glares at @Kaumudi). Nah, it isn't anything serious...but I like that 'no-nonsense' response of yours ;) As typical of you Mods. ^_^

@orthocresol And at least one non-chemist who likes to play with all of the shiny chemistry toys.

@Kaumudi Wait...but I wasn't pinged! Great, now everyone's ignoring me -_-

@AaronAbraham I officially am not ignoring you. (I have no idea what the conversation's about, but.)

@orthocresol @AaronAbraham Just beware that the 3d member of each triad typically behaves quite differently from the 4d and 5d members.

@hBy2Py Ignore that bit, I was just horsing around ;P

@AaronAbraham what I have done to you :(

4:18 PM

@AaronAbraham I know. So was I. :-)

@hBy2Py @ortho 0_0

@hBy2Py I couldn't be sure 'bout your case though ._.

@koolman What have you not done to me?

Wait...I think that sounds wrong^ ._.

Tell me , So I will not do it again

@AaronAbraham Yep. e.g., $\ce{Mo} \approx \ce{W} \not\approx \ce{Cr}.$

Hi

@hBy2Py I'll interrogate ortho tomorrow...kinda tired now ;)

Wait @hBy2Py you're Brian?

@Mithoron \o/

4:22 PM

@AaronAbraham Yep. I pulled a @M.A.R. a couple of months ago.

Ah :D

After @Mart complained about how hard it was to abuse his mod powers and superping me, what with how many other "Brian"'s are in the SE usernamespace.

;-)

@AaronAbraham tell me

I actually wanted to change my name to paracresol and replace my display photo with a black seal...but I think that'd piss @ortho off XD... Pissing a Mod. off is no joke ._.

@hBy2Py However I don't get the 'snake' which was used instead of Pi 0_0

@koolman This is exactly what you keep doing to me ;P

@AaronAbraham Hahaha, no, I figure he'd think it was hilarious.

Just don't use the name "paracresol ◊"

@AaronAbraham I'm programming computational/quantum chemistry related stuff in Python in my spare time.

4:27 PM

@hBy2Py NOW I MUST!!!

@AaronAbraham Sooo, @ortho ... I think I made a boo-boo....

@AaronAbraham this is done by me first time . Because you are spreading wrong news to everyone about me and I wanted to know why

@hBy2Py Gimme a minute...I'll rub some salt into that 3;)

CRAP! @ORTHO'S HERE!!!

@AaronAbraham Shouldn't have pinged him ;D

@Mithoron Oh. I made sure to ping him.

2

Would've been no fun at all otherwise.

4:30 PM

@AaronAbraham You can't use the diamond symbol in your name, even if you wanted to. :)

@hBy2Py As did I :D

@orthocresol Why not? Seems possible ._.

@AaronAbraham Seems like the sort of thing the SE devs would have written a check for.

Looks there were like 6 pings to ortho in half an hour :D

A: Is making yourself appear (at first glance) to be a moderator acceptable behaviour?

@hBy2Py Exactly.

18

The user name field already has a filter that removes the Unicode ♦ character (and some look-a-likes) used to identify moderators. Users are not allowed to spoof this as part of their username. This seems like a reasonable guideline to me. Intending to deceive the community by making yourself ou...

@koolman "Wrong news"? Apart from the time in the 3th grade I told everyone the world was going to end by 2012 and got them to throw to pool in for a pizza party before we 'die' [in the midst of the commotion, I managed to get away with paying for my share 3:) ]...I haven't spread any "wrong news" as of yet ಠ_ಠ

@hBy2Py Crap...I was counting on it :(

4:35 PM

@AaronAbraham There are lots of things that would be fun to do on SE as a joke, but that have too many nefarious implications and so they're either made impossible by SE design or slammed down upon by various levels of mods if anyone does them.

I mean, you always could change your username and profile pic. There's nothing wrong with that.

Just that... it's probably better for you to be yourself, instead of copying others :)

I run through the "OOOOH! That would be fun!" "Aww, I can't do that??" "Oh. Yeah, I see why not. sigh" emotional cycle with relative regularity.

3

@AaronAbraham then I have not done anything wrong to you

@orthocresol HEY! That was totally original. ಠ_ಠ

@koolman Way to go Gandhi!

@hBy2Py I actually really want to create a new account, and suspend it for fun just to see how it looks like "from the other side". The issue is that this notifies all the other mods and I don't really want to spam their inboxes with rubbish like this, haha

4:38 PM

@hBy2Py I'm actually kinda used to that by now ;)

@AaronAbraham you don't have any answer of mine

Of what I have done to you

....

Yeah. This place has had quite a number of years to evolve and I get the feeling that nearly all the possibly-harmful stuff that users can do have been stripped away.

@orthocresol For every warning label, there's some fool that's done the stupid thing warned against.

For every restrictive feature in SE, there's someone that's used it for something nefarious.

I've been that fool more times than I would like to admit.

Yup, pretty much. Chem is great though, our job mostly just consists of closing HW questions.

4:44 PM

On an entirely self-aggrandizing note, this is by far the largest number of starred chats I've ever had at one time.

2

I see, @AaronAbraham is attempting to make himself look like @paracresol, but doesn’t understand the way chat profiles work.

@Jan I'm trying quite hard actually -_-

@Jan :-D

Obviously, something is not working.

Why the 'eck sin't my chat profile changed too???

4:51 PM

Should we explain or should we let him struggle?

@Jan The former :3

It's kinda fun to see the struggle, you know … being on the other side …

@Jan I could help it change, then change it back again.

xDDDDD

maniacal laughter

2

4:52 PM

@orthocresol ಠ_ಠ

I see, my vote for @ortho being mod was worth every fraction of it!

@Jan So...you only gave @ortho a fraction of a vote? ;)

There he goes....

Everybody gave ortho a fraction of a vote.

3

Darn...THIS ISN'T WORKING! -_-

4:54 PM

Evidently, it was just enough to overcome the evil forces of @M.A.R.

@orthocresol and thus the Universe was saved...

Seriously though, I've gotta go collect my bike. Have fun figuring out how SE chat works ^^

frustrated

!!doubleflip/@Jan

uɐᒋ@︵╰(゜Д゜)╯︵@ᒋɐu

!!doubleflip/@ortho

4:56 PM

oɥʇɹo@＼(｀д´)／@oɹʇɥo

WHO THE HECK IS THE SERIAL STARRER HERE?!

he who smelt it dealt it, as they say...

3

._.

...

(I'm saying it's you and you're trying to pull one over on us.)

It isn't me ._.

4:58 PM

It can't be @AaronAbraham because @AaronAbraham can't star his own posts.

Beholdeth the German speak!

2

@Jan...

Now that you mention it, I've never tried starring my own posts...of course it doesn't work.

19 mins ago, by hBy2Py

For every restrictive feature in SE, there's someone that's used it for something nefarious.

Say, … I’m using the Ubuntu software-centre distributed TeXLive. Can I update a package by downloading the .sty file from CTAN and then simply replacing the existing one or is that bound to fail?

I don't see why not?

5:01 PM

'Twas not me

Doesn't pdflatex search the current directory for style and class files first, though?

That might be the simplest thing to try before you start sudoing all over the place.

It would be xelatex in my case, but yeah, I think it might.

I should try.

ok, report back success/failure

If worst comes to the worst, copy the system .sty into the current directory, replace the system spot with the downloaded one and what the hard drive explode …

Tomorrow. ;)

Gotta go to the sauna now.

sauna!

5:03 PM

Or actually, that could be a dirty lie; maybe I’m just going to do it after the sauna.

still frustrated

Right, bye o/

o/

@Jan o/

chemistry.stackexchange.com/users/33991/paracresol?tab=profile

YES!!!!!!!!!

IT WORKED!!! @Jan @orthocresol @hBy2Py :D

Wait....

Why the hell won't the username change? -_-

...

@AaronAbraham Chat is quite distinct part of SE

We can treat it as experiment how quickly will it actualise ;)

5:18 PM

@Mithoron But M.A.R/Rubisco/DEAD/PhMgBr got to change his name -_-

!!gun

( ͝ಠ ʖ ಠ)=ε/̵͇̿̿/’̿’̿ ̿

@AaronAbraham Looks you only changed your username for chem SE :(

6:27 PM

@AaronAbraham Since your parent account for chat is physics.SE, not chem.SE.

spoiler alert

2

@Loong ?

you ruined it!

Oh, you mean I should've let Aaron get even more frustrated and confused?

2 hours ago, by Jan

Should we explain or should we let him struggle?

6:31 PM

Blame it on studying biology. It has made me dumb.

Well, when you put it that way...

I think it's OK :p he's probably gone to sleep by now, so he'll only know tomorrow...

CowperKettle

@M.A.R. biology is great

+1

What the heck serial starrer . . . I'll find you and that day will be your nightmare

2

6:34 PM

Incidentally, how do you refresh a chat room, @Loong?

CowperKettle

Good night

@CowperKettle Yes, but not high school biology and the bullshit we have to take in Konkur.

@orthocresol refresh a chat room?

@orthocresol My thoughts are so dispersed, I can't get them to agree on being in one answer.

Yeah, like to update the usernames, profile images, etc.

6:35 PM

@orthocresol F5?

yes, press F5 to update the client side

A: How long does it take for chat profiles to update?

I thought there was some moderator thingum to refresh on server side.

As hinted at here

10

Chat profiles sync once an hour. A moderator can trigger a refresh, but generally, just wait a bit.

@orthocresol you can refresh a user profile on the chat server, but not a room

Ah, I see.

Oh right, I just found it :D

Thanks

ok, so you mean "refresh profile from parent site"?

6:48 PM

Yup.

ok

7:09 PM

@Loong also, are you editing this answer? chemistry.stackexchange.com/a/27680/16683

A: Is Earth's orbit altered by recoil from take-off/launch/recovery of aero/space vehicles?

-5

Fat people are causing earth to spin faster, lose weight.

@orthocresol no, not yet

ok, I can do up the maths first.

just don't want to run into the two-people-simultaneously-editing problem

yes, ok, I thought as much

dinner time!

7:15 PM

time dinner!

din ti ner me

Or like this for chineses ¡ ǝɯıʇ ɹǝuuıᗡ

7:46 PM

Huh? How is that Chinese..

@Hexacoordinate-C Not Chineseseses, but Australians I believe

@M.A.R. :D

Guys I have a question

I have many questions.

Ahahaha :')

Even though in practice, you don't form carbonic acid from an acid and a carbonate, could you still say both are correct?

8:02 PM

Your L's and C's are indistinguishable

Yeah I realised I wrote that quite badly, sorry.

@MichaelHarding I guess so. Sometimes correct isn't just . . . correct, but what people want it to be.

If you hate H2CO3 with a passion, you'd say two is wrong.

If you like to cite the articles that successfully isolated H2CO3 in some weird phase you'd say one is wrong.

There's an equilibrium with water and carbon dioxide that goes to carbonic acid, but only a very small amount of carbonic acid would be present

Mhm. But that's not nonexistent

In that solution, you won't find S8. H2CO3 and S8 aren't in the same level. One is a product of a reaction that's happening there, and the other is just not there

well honestly I'd argue that H2CO3 is wrong

maybe somebody isolated H2CO3 in a 77 K argon matrix, but unless you're running that reaction in a 77 K argon matrix, you're not gonna get H2CO3

Even in the aqueous phase, most of the CO2 exists as CO2(aq), not H2CO3, if I'm not wrong.

BTW, for the interview, it might be a good idea to know how to identify the phase diagram of water. :D

It's another recurring theme, I believe.

8:09 PM

Hmmm, 'theoretically' could you say both are correct? Although I agree, in practice I'd also argue H2CO3 is wrong.

I went to this masterclass at Cambridge and we had a talk on water where he covered all sorts of chemistry, phase diagrams were brought up

Theoretically, you could probably say that. However if you don't want to be laughed at, I'd recommend you subsequently specify that H2CO3 (aq) decomposes into H2O + CO2.

@orthocresol The equilibrium constant for CO2(aq)/H2CO3 is something between 350 and 990.

@Loong Which side does it favour?

CO2(aq)

A: Does H2CO3 exist in solution?

4

Aqueous carbonate solutions contain four different solute species: $\ce{CO2(aq)}$ $\ce{H2CO3}$ $\ce{HCO3-}$ $\ce{CO3^2-}$ The equilibrium for the hydration reaction $$\ce{H2O + CO2(aq) <=> H2CO3}\tag1$$ lies to the left. The corresponding equilibrium constant $K$ at $25\ \mathrm{^\circ C}$ ...

8:12 PM

Ahhh :)

@MichaelHarding The thing about water is that ice is less dense than water. So, the solid-liquid phase boundary slopes backwards.

@Loong Did you recall those numbers offhand o.o

There's only one number I remember offhand, and that's the pKa of acetic acid.

What "offhand" means ?

@orthocresol No, but I mention a source in my answer ;-)

Without looking it up.

;D

^^

I know acetic acid, ammonia, phenol and common group of organic chemistry

8:16 PM

I also know HCl's pKa. Shame on you Ortho.

@orthocresol amazon.com/Aquatic-Chemistry-Chemical-Equilibria-Natural/dp/…

I mean, I know the approximate values for all the usual functional groups.

But I only remember acetic acid to 2 d.p., which is 4.75

4.8 is ok ^^

4.76.

Oh well, rounding error

It depends on temperature

8:17 PM

@Loong Holy crap that's huge

Amazon oneboxes remind me of whales

@M.A.R. Hmm, some say 4.75, some 4.76. We're both right, I guess.

I think 4.76 seems righter, actually

4.76 is more. It must be right.

I guess I don't remember any numbers offhand ;D

Who care for a difference of 0.01 on pka?

Maybe pi: 3.14159265358979323846264338327950288

8:19 PM

cares

Seriously lol

Hey, it matters when I'm working on a 0.01 nmol scale and I have to measure the diameter of my round-bottomed flask.

More seriously, it's something I memorised as a bored 15-year-old kid and it just hasn't gone away.

xD

@Hexacoordinate-C WE DO

@orthocresol CRC Handbook says 4.756 at 25 °C

Well what the uncertainty ?

8:22 PM

Damn.

What the uncertainty indeed

What are the experiment conditions ?

Just wait. In three years' time I'll have an article in Angew Chem titled "Revisiting the pKa of acetic acid".

Pressure, temperature, distillated water at the begining ? how much D2O, T2O ?

And the good old IUPAC list says Ka=1.754E-5.

That's also pKa=4.756.

8:28 PM

evans.rc.fas.harvard.edu/pdf/evans_pKa_table.pdf 4.76 for them too

History shall remember this day as ''when Ortho's pKa bowed down to MAR's''.

I propose a new constant. MAR's constant = 4.76

It has many uses! It's the pKa of acetic acid.

So if you power ten by the MAR constant, you get the Ka of acetic acid.

Lol

Far far far from the Nobel Prize

LAUGH AT ME YOU MIGHT BUT I WILL PROVE IT

Picturing Hexa bowing down to him in thirty years after getting a Nobel prize and getting a smug expression of ''I told you you ignorant fool''

Can you make a law involving only the number of each kind of atom in a molecule to get the pka with 2 digits after the decimal point ?

Nonsense question because what about isomers ?

Take care of everything then

@Hexacoordinate-C huh

8:35 PM

Ahah

If I want to know exactly pka of both fumaric and maleic acids ..

Do experiments for me

You'll own nothing just do it like a good boy :-)

earn

@M.A.R. $10^{-c_\mathrm{MAR}}$, not $10^{c_\mathrm{MAR}}$.

Oh, right.

Depends if M.A.R define the concentration maybe negative ?

For his Nobel Prize ?

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry 2054 to

M. A. Ramezani
University of Chemistry.SE

"for his development of a new theory of acids and bases"

After Arrhenius, Bronsted, Lewis, Lux-Flood, HSAB we have @M.A.R. haha

I forgot Usanovich

try

8:45 PM

Usanovich acid-base theory: "NEARLY EVERYTHING is an acid. EVERYTHING ELSE is a base."

@orth

Almost yes ^^

Is there somewhere a compilation a every true rules which works everytime in organic chemistry to do a mechanism without trouble in any reaction?

Because I agree with my teachers it is useless to learn organic reactions there are just specific cases

"basically just draw arrows n stuff"

Seriously though, I fail to see how a rule that works for ionic reactions would work for pericyclics.

Or radicals.

I mean rules like, Hoffmann, Thorpe Inglod, Baldwin, Woodward, Zimmerman Traxler, Felkin Anh

Not rules but things that help

If you know them and if you have a brain you don't need to have a lesson about how to unprotect any alcohol group for example

How do those rules help you decide how to deprotect an alcohol?

If I give you reagents you must find the correct mechanism without write horrible things

8:56 PM

Yeah. I mean let's say you protected a phenol group as its methyl ether. The "standard" deprotection is BBr3 but how do any of those rules come in?

To me, the only guiding principle is really "nucleophile attacks electrophile".

If you know the properties of elements etc

I mean really all rules

Or experiment facts (basic ones at least)

Well, you can solve a lot of those questions if you understand basic things like nucleophilicity/electrophilicity, stability of cations/anions/radicals/.... and so on

For example I give you a swern to do but you never did it you don't know it. I give you the rules and then you do it

I don't think that there are such simple rules that it would be easier to use those. Organic Chemistry is a lot of just learning by heart, but if you actually understand the "logic" behind it it will get extremly easy to "remember" all those mechanisms, because you will be able to reproduce it even if you remember only parts of it.

For swern for example I know the starting materials, I know DMSO reacts first with oxalyl chloride (and I know how that one usually reacts) and then with the alcohole and somehow base is involved. This leads to two reasonable mechanisms

but well, years of teaching that stuff in labs helps too:-D

9:11 PM

I mean if you know those rules you don't have to learn by heart the reactions

I would prefer to have a lesson with rules and example than all about alcohols, amines, ester, organometallic ...

Obviously only rules will be tricky we all need to do things on example

I just prefer to think by myself first and correct if it's wrong

Because you don't need to have a lesson in which the teacher gives you mechanism of Shapiro reaction to do it by yourself if you have some habits in organic chemistry

I really don't believe that such a thing exists.

I second that. But the Shapiro reaction is actually a pretty nice example, because you can solve that with very basic knowledge. All you need to know is identify the two most acidic protons and know that tosyl is a good leaving group.

You don't need to know that it is a good living group

You just need to draw some resonance structure and say "yes it must a good way"

There is not always exact mechanism but some which are more probable than other

(And sorry for my bad orthographe this evening)

yes, ofc you can determine the quality of the leaving group by looking at resonance structures too. Those are just burned into my brain so I don't even think about this usually:D

9:28 PM

heya guys

I have a question

Can a dissociative interchange reaction exhibit pseudo-first order kinetics if the incoming ligand is the solvent (much larger concentration)?

It's possible in my understanding but it certainly doesn't have to be. This would me more of a special case

my book says "Increasing [Y] (the incoming ligand concentration) will NOT lead to saturation kinetics with I (interchange mechanism) as predicted when D (dissociative mechanism) is operative". Does this mean no pseudo-first order rate constants for Id?

basically I was given rate constants for exchange of a chromium (III) complex with the solvent as a ligand, for three different solvents

they all had units s-1

so I figured it was the pseudo first order case of Dd mechanism... and I figured it wouldn't be Id since Id is bimolecular, but then my friend told me that small 3d ions generally follow the Id mechanism and she argued that the bimolecular Id mechanism could follow pseudo first order kinetics anyways.

does "saturation kinetics" mean pseudo-first order rate laws? If so, does that mean no first order rate constants for Id mechanisms?

Well, if it's usually second order then pseudo first order is possible, no matter what. The question is if your interchange is second order, sind something like ML <-> M -> ML' might not be second order.

saturation kinetics is a term I've only heard in enzyme kinetics, where it means more substrate doesn't increase rate

in pseudo first order there's no saturation kinetics, more of the excess substrate equals higher rate

OK so I'm just going to ignore that quote then

and assume that my friend is right

the thing is that my book specifically talks about the Dd mechanism being able to exhibit pseudo-first order kinetics when [incoming ligand]>>>>[complex]

but the book doesn't mention pseudo-first order kinetics for Id mechanisms (which are bimolecular), however I figure it could happen.

ah ok I think this is Id just because it's a small d3 ion

but I still want to know what "The I and D mechanisms can be differentiated in principle since increasing [Y] will not lead to satura- tion kinetics with I as predicted when a D mechanism is operative." means