The Periodic Table

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CowperKettle

05:41

Q: Iron (II, III) oxide and concentrated nitric acid

$$\ce{Fe3O4 + 10HNO3 -> 3Fe(NO3)3 + NO2 + 5H2O}$$ Since $\ce{Fe3O4}$ is really $\ce{Fe2O3*FeO}$, why don't we have instead $$\ce{Fe3O4 + 8HNO3 -> Fe(NO3)2 + 2Fe(NO3)3 + 4H2O}$$ Why does the reaction evolve gaseous nitrogen dioxide?

reaction

Good morning all!

Is this the answer to my question?

Because NO2(-) seeks to transform into NO2 more actively than Fe(3+) wants to transform into Fe(2+)?

I'll be lurking, solving othe problems

2 hours later…

CowperKettle

07:59

Because nitric acid is a powerful oxidizer, and when it sees something to oxidize, it does not think twice. — Ivan Neretin 12 mins ago

CowperKettle

08:16

You don't memorize reactions. Also, I'm not sure whether you should memorize the electrode potentials table (I, for one, do not). I just have a vague feeling about some oxidants being "strong" and the others "weak", and that's enough for most situations. — Ivan Neretin 5 mins ago

"You don't memorize reactions" - the single most preposterous statement about chemistry that I know thus far. For some reason I see it repeated by different people.

3 hours later…

CowperKettle

11:20

Why do we get NaHCO3, and not just NaCO3?

1 hour later…

CowperKettle

12:30

I got a nice answer to this.

Because we need to put a lot of CO2 in the solution, so as to bring the pH lower.

At a higher pH, our Al(OH)3 will dissolve back into the ionic Al(OH)4(-)

Nice.

Putting a lot of CO2 gives as the hydrocarbonate

or bicarbonate

3 hours later…

CowperKettle

15:14

evening

user116211

hey, good evening

CowperKettle

16:10

How is your reading, that hardcore math book?

user116211

@CowperKettle Well, it is not hardcore; it's an introductory piece.

CowperKettle

For you, maybe.

I'm slowly going through the Problem 37 sample questions of the Russian USE exam.

user116211

Hmm... you just need to know a bit abstract algebra and finite-dimensional vector spaces and their properties; the book is more or less self-contained and very intuitive.

CowperKettle

Oh, the finite-dimensional bastards? I know them as the palm of my third hand.

user116211

CowperKettle

16:14

(0:

1 hour later…

Fiksdal

17:21

@MAFIA36790 Hey, you guys still around?

CowperKettle

18:06

I guessed this chain of reactions correctly! Yay.

The first chain of reactions out of several dozens that I managed to guess correctly.

From the textual description.

The last one was tough, because there you suddently get Al(OH)3 and CO2 and H2O

Because the solution is alkaline, and H2CO3 dissociates

Good evening, Ortho!

user116211

@Fiksdal Sorry, kinda bit offline. don't wait for one; if you have question, put it here - any interested one would answer it :)

Hippalectryon

Where is Chemobot O_o

user116211

Hey, @hippa.

user116211

yesterday, by MAFIA36790

where is @Chemobot?

Hippalectryon

How long ago did he disappear ?

user116211

18:16

@Hippalectryon exactly that very moment; for I saw its icon still there at the column right.

Hippalectryon

@Chemobot Stop slacking off ._.

CowperKettle

(0:

Hippalectryon

!!img/stupidbot

Chemobot

No result found.

CowperKettle

!!img/whiskey

Chemobot

18:18

No result found.

Hippalectryon

!!!img/LSD

CowperKettle

!!img/potassium dichromate

Chemobot

user116211

So, your oral exams are over @hippa?

Hippalectryon

@MAFIA36790 No, they're starting this Monday

In between our written exams were being corrected

user116211

18:20

ah... hmm, okay.

Hippalectryon

Aaand I did well enough everywhere in the written exams to pass the oral exams :D

user116211

I'm here meanwhile reading some good number of books before my classes get started.

user116211

@Hippalectryon great; !!ice cream

Chemobot

Hippalectryon

thanks :-)

user116211

18:25

Goodnight comrades; it's night and silent here - a good time to entertain myself with the 'hardcore' math books ;P

CowperKettle

Good night!

Shubh ratri!

Fiksdal

@MAFIA36790 Hi.. I just wanted to ask for advice before posting a question. But I've already posted it now. chemistry.stackexchange.com/q/53341/30314

@MAFIA36790 Oh. I see you already left. OK, goodnight.

CowperKettle

18:40

I wonder why we get bromine in line 3

Would we get chlorine if we used HCl instead of HBr?

Fiksdal

@CowperKettle Ratri is from an Indian language, right?

CowperKettle

@Fiksdal yes

Fiksdal

In a lot of them, actually. But which one were you speaking?

CowperKettle

Hindi

Fiksdal

cool

They use it as a loanword from Sanskrit even in South India

CowperKettle

18:44

I don't speak Hindi, I only know a couple of words

Fiksdal

Maybe MAFIA speak Hindi, and that's why?

CowperKettle

yes

Fiksdal

Man, I feel so smart. Decoded the whole mystery.

user116211

Okay, I didn't left...... I came here to post a message ;)

CowperKettle

(0:

user116211

18:47

so, I'm giving a hard shit in getting point groups....

user116211

So, can anyone give me a good source on it?

CowperKettle

How to say "See you tomorrow" in Hindi?

user116211

I've read Jan

CowperKettle

Kal milte hain?

user116211

the preliminary ideas are pretty clear to me;but I'm having problems in conceiving the nomenclature especially...

user116211

18:49

@CowperKettle yes.

CowperKettle

Kal milte hain then!

user116211

@Jan could you help?

user116211

I've actually read Atkins; at the point of nomenclature; it becomes hardly comprehensible ;_;

Jan

19:11

@MAFIA36790 Huh?

Mithoron

19:30

@Jan o/

Jan

@Mithoron o/

Have I ever mentioned that I hate our polarimeter?

Loong

@Jan yes

Jan

Goddamnit D=

This is the bugger, btw

Mithoron

19:46

@Jan Oh no how to unsee this abomination!? :D

Hippalectryon

@Jan I'm used to those only :-)

Jan

Mithoron

@Hippalectryon Gah, my eyes! :D

Hippalectryon

@Mithoron They're actually rather good !

Jan

It actually looks like working with that one be less of a pain than the one I'm stuck with~ …

Hippalectryon

19:53

@Jan How does yours work ? Like a spectrometer ?

Shadock

20:13

Hello
Where can i find a file with the color of each ions of all elements of the periodic table in solution ?
And in general in salf

Shadock
Shadock
1189
For example Erbium III chloride is pink
Copper II is blue etc
All elements ! :D
?
Thank you in advance

Hippalectryon

@Shadock o/

Jan

@Shadock Probably you will have to make one because there are way to many possibilities … Otherwise, the Hollemann-Wiberg is always a good starting point.

@Hippalectryon Pretty much. Enter sample, read value. So far the theory. In practice: Read 20 values, average them.

Hippalectryon

@Jan ._. that must be a pain

Shadock

OK thanks I'll do it so :)

Jan

@Hippalectryon It is. I avoid measuring optical activities whenever possible. Unfortunately, I need them for the dissertation >__<**

Shadock

20:19

Polarimeter is so good

Loong

Hello, everybody! Check your badges. We currently have an interesting bug.

Shadock

One of the only way to mesure the Rydberg constant with all precision we have :D

Hippalectryon

@Loong excavator ? I was wondering the exact same thing

Loong

@Hippalectryon and Marshal

Hippalectryon

@Loong I don't have that one

Jan

20:20

@Loong Yeah, I got a second excavator on A&M =D

*crossing the fingers for a third excavator badge … and that I get to keep them =D*

Loong

We're investigating. — Adam ♦ 9 mins ago

Jan

Saw that one.

Another cool thing about the polarimeter @Hippa, is that it took three and a half hours to stabilise for the solvent zero ~.~*

@JAL Resounding no. — animuson ♦ 3 mins ago

Shadock

An average time to make a chromatography

Jan

=C =C =C =C =C =C =C =C

Hippalectryon

@Jan What's its precision ?

Jan

20:29

@Shadock Is twenty minutes.

Shadock

Try to make a chromato of the solvent during you do the zero :P

Jan

There are three digits I can see.

Shadock

A chromato usually take much more than only 20 minutes lol

Hippalectryon

@Jan ._. it's as precise as my mechanical one then :P

Invert in a good old Laurent polarimeter :DD

Jan

I have no clue whether the full stop between those and the first two digits is a comma or a thousands separator.

Hippalectryon

20:31

Most likely a comma. What unit of polarimetry uses thousands ?

Jan

There is nothing in that instrument that wouldn't surprise me ;)

Shadock

You never used a Laurent Polarimeter?

Jan

I haven't, no.

Mithoron

@Loong Maybe for a while but I have three Marshal badges now :D

Jan

@Shadock As my supervisor once said:

> 20 minutes. Including evaporation.

Shadock

20:33

To make a chromato?

Jan

It's a running gag in our group xD

Shadock

Lol

Jan

For a column, yeah.

My personal record is 29 minutes.

Shadock

HPLC in 30 minutes

Nice

Jan

Deducting the time to colour the TLC because the colouring solution was far away.

No, Flash.

Shadock

20:35

what TLC is ?

Jan

Having a solvent mixture with high isohexane content for easier evaporation, a fast column, capturing ten fractions only, deducting the time for packing the column, knowing where the spot is, being a tad too polar with my eluents and faking a lot of other statistics ;)

Thin Layer Chromatography.

Hippalectryon

Isn't TLC... not on columns ?

Shadock

@Hippalectryon what is the name for "TP" in english ?

Jan

You need to know where your product is, so you do a TLC of the fractions.

Hippalectryon

@Shadock Experiments ? :P I'm not sure

Loong

20:38

A: Excavator and Marshall badges are being awarded over and over

We just did a major revamp of how badges are awarded behind the scenes to drastically reduce the load on SQL Server. It now takes advantage of some pre-compute work we're doing to track badge progress in the profile. However, I screwed up 2 queries, specifically the text names of the badges that...