The Periodic Table

pentavalentcarbon

3:08 AM

@orthocresol Almost makes me want to be an organic chemist. No, that's a lie.

Though learning hybridization and VB theory might be sufficient.

user228700

3:43 AM

Hi everyone :-)

pentavalentcarbon

o/

user228700

Does anybody know any geometry? I'm learning about the radical axis and I have a quick question that I've asked at MSE Chat, but everybody's discussing something else.

pentavalentcarbon

What's the radical axis?

user228700

:-P It's related to circles.

pentavalentcarbon

You mean this thing? upload.wikimedia.org/wikipedia/commons/thumb/4/4c/…

user228700

3:47 AM

No, that's the unit circle for trig.

pentavalentcarbon

Right. I can't imagine any other circle though. Haven't taken geometry in...12 years?!

Can you post a picture?

user228700

Oh, wow.

user228700

Nvm, then.

user228700

I'll ask DHMO. Maybe he'll know. Thank you :-)

pentavalentcarbon

Yeah, I'm probably useless.

user228700

3:50 AM

:-P 12 years is a very long time. But thanks for offering to help :-)

user228700

@DHMO: Since u've asked me to leave u questions, I've pinged u. U know anything about the radical axis of two circles?

getafix

5:28 AM

Geometry...shudders

M.A.R.

6:25 AM

@orthocresol The answer version of Nadine?

user228700

7:51 AM

@getafix :-P It's not all bad...

DHMO

8:08 AM

@Kaumudi what is the question?

mathworld.wolfram.com/RadicalLine.html

user228700

8:41 AM

I have a quick question. What is the difference b/w evaporation and vaporization? None of my books/websites do a good job of explaining this difference.

DHMO

@Kaumudi vaporization includes evaporation which takes place below the boiling point and boiling which takes place at the boiling point

user228700

So vaporization cannot take place at any temperature other than the boiling point? Wait, maybe I didn't get it right. Can u pls elaborate?

DHMO

boiling occurs at the boiling point

evaporation occurs below the boiling point

vaporization is the general term for boiling and evaporation

user228700

Do u know a good source to learn this? I've searched and searched. Maybe it's just 'cause I'm sleep deprived, but yeah...anything?

DHMO

Vaporization

Vaporization (or vaporisation) of an element or compound is a phase transition from the liquid phase to vapor. There are two types of vaporization: evaporation and boiling. Evaporation is a surface phenomenon, whereas boiling is a bulk phenomenon. Evaporation is a phase transition from the liquid phase to vapor (a state of substance below critical temperature) that occurs at temperatures below the boiling temperature at a given pressure. Evaporation occurs on the surface. Evaporation only occurs when the partial pressure of vapor of a substance is less than the equilibrium vapor pressure. Boiling...

> Vaporization (or vaporisation) of an element or compound is a phase transition from the liquid phase to vapor. There are two types of vaporization: evaporation and boiling.

user228700

8:47 AM

Wikipedia? Really? OK, I'll check it out after my nap. Thank you!

DHMO

9:00 AM

@Kaumudi what is wrong with Wikipedia?

user228700

9:37 AM

@DHMO So there are types of vaporization.

DHMO

@Kaumudi yes

user228700

It says "vapor (a state of substance below critical temperature)"

DHMO

@Kaumudi yes?

user228700

I'm trying to figure out what that really means...

DHMO

> critical temperature
nounCHEMISTRY
the temperature of a gas in its critical state, above which it cannot be liquefied by pressure alone.

user228700

9:47 AM

Ik the definition.

DHMO

then what is your confusion?

that means gases are considered as vapour as long as they can be converted to liquid by pressure alone, without changing the temperature

user228700

At atmospheric pressure, what is this temperature?

DHMO

note that vaporization takes place at a fixed temperature

it is different for different gases

user228700

Yes, right, sorry, I meant to ask about water.

DHMO

> In water, the critical point occurs at around 647 K (374 °C; 705 °F) and 22.064 MPa (3200 PSIA or 218 atm).

it does not depend on the pressure (for obvious reasons)

user228700

9:54 AM

Perhaps I need to revise my notes...

user228700

Thanks :-)

DHMO

@Kaumudi what is the obvious reason?

user228700

What obvious reason?

DHMO

@Kaumudi why does the critical temperature not depend on the pressure?

user228700

Idk. That's why I need to revise my notes.

DHMO

9:58 AM

@Kaumudi what is the definition of critical temperature?

user228700

Well, it says "no matter how much pressure you apply" so.

DHMO

precisely.

user228700

Aah, now I'm super confused about all these critical constants.

DHMO

@Kaumudi what is your confusion?

user228700

Hang on, one sec...

user228700

10:07 AM

OK, the definition of critical pressure is given as the "minimum pressure that must be applied to convert the gas into liquid"

user228700

"Gas" being the term used to describe the stare of a substance beyond critical temperature?

Bounty Hunter

2

Q: Why is 5d filled before 4f in Lanthanum?

I know they are of similar energies. But why does one electron enter 5d and the later ones in 4f.

inorganic-chemistry

orthocresol

I got a bad feeling about that bounty. OP of that question isn't active. Oh well..

DHMO

@Kaumudi no, vapor is still gas

user228700

@DHMO Aah, dumb question. Sorry, so what's not vapour?

DHMO

10:10 AM

@Kaumudi no idea

@Kaumudi looks like your definition of critical pressure does not align with the above diagram

user228700

Not at all.

user228700

In fact, it perfectly alligns with my definition.

user228700

Think about it: I said "minimum" pressure.

user228700

Which is valid only at critical temperature. Now look at the diagram...

user228700

Anyhoo, thank you :-) Gonna do some physics now.

DHMO

10:23 AM

@Kaumudi there is liquid phase in the diagram below the critical pressure

user228700

Huh.

orthocresol

11:11 AM

-7

Q: Draw a tripeptide at pH 2?

How does the backbone of a peptide look at $\mathrm{pH}\ 2$ ? know that at low pH the amino acids have a $\ce{-NH3+}$ and a $\ce{-COOH}$, but when the residues link where does the additional hydrogen of the carboxyl go? (please mention where it is linked and if it is bolded or dashed)

homework ph amino-acids

why is this being VTC'd?

Lousy question it may be, but it's not HW.

Now, this is really unclear...

-1

Q: Probability of finding electron in 3d vs 4s

I am currently studying High School Chemistry and after studying atomic structure, one question struck my mind. Where is it more probable to find an electron 4s or 3d. Now 3d is certainly nearer to the nucleus of the atom but still 4s has a lower energy. Kindly help me out in deciphering this th...

physical-chemistry atoms

user228700

11:57 AM

Hm, @DHMO: Perhaps it's s'posed to be "max. pressure"?

DHMO

@Kaumudi dont think so either

M.A.R.

1:22 PM

→ 3 messages moved to Sandbox

-1

Q: Is atomism atomic theory?

I would like to ask the meaning of: atomism atomic theory. I just want to ask if the word atomism also means atomic theory? According to dictionary.com both of them are the same. But why I do not see the word atomism used in the text book!?

atoms history-of-chemistry

This was tagged as MOT. O.o

Also WTH, it's not unclear!

If it happens again, I'll prolly go and rant on meta so people would use their votes meaningfully.

Zhe

3:00 PM

Do you guys have a standard template to paste into obvious homework questions?

pentavalentcarbon

I keep a Markdown file with a couple versions, one moment...

now that I look at it I see it's got a few unicode nasties in it that I need to clean out

Zhe

@pentavalentcarbon You said you wanted to ask about my background before. I'm around for the next 45 minutes, so feel free to bug me.

pentavalentcarbon

ok I'm gonna make a gist first

These are the templates I tend to use: gist.githubusercontent.com/berquist/…

Zhe

3:17 PM

@pentavalentcarbon Bookmarked and used. Thanks!

pentavalentcarbon

Ok, pestering time.

Did you have any background in software development before leaving academia?

Zhe

You mean like writing really shitty code?

Because in that case, yes

But I would probably die from shame if I looked back at any of that stuff now...

pentavalentcarbon

I mean, I don't even know how to define "shitty code" anymore.

It seems like everyone has a different definition.

But anyway.

Zhe

I was an organic chemist

So, I wasn't writing code for actual work

I wrote some python code for parsing Gaussian output

And I wrote a GUI for the the crappy text based NMR reservation software

Maybe the right way to say it is this: I went back to grad school for a CS degree

pentavalentcarbon

MS or PhD for CS?

Zhe

3:28 PM

MS

One PhD is enough :/

pentavalentcarbon

I can agree with that. I'm not sure I want another degree though if I can help it, though I could probably get into the Master's program at my undergrad if I wanted to.

Did anyone tell you "hey, you should get a MS in CS, otherwise no job for you"?

Zhe

No

I could've applied to an industry job

I did apply to some teaching jobs

But I was so sick of lab, that I just needed to get out

I ended up teaching high school chemistry at a private school for two years

pentavalentcarbon

Ok, our backgrounds are slightly different, but that's fine.

So you already had the MS when applying for software development jobs?

Zhe

Yup

Well, I was in the middle of it

I applied while I was in the last semester

Also, I did two summer internships at various places

Anyway, now I have a nice job that doesn't require me to use chemicals

pentavalentcarbon

Would you say this chemical-free job was "easy" to get?

Zhe

3:39 PM

Eh, it's hard to say

I didn't run into any road blocks, but knowing the system, there's probably a lot of luck to it

Vedant

what does this mean

pentavalentcarbon

I take it the internships meant you had "good" code to show at interviews?

Zhe

No, the internships just gave me some experience I could put on my resume.

And they taught me what better code looks like

Vedant

@pentavalentcarbon @pentavalentcarbon @Zhe think you can help me out??

Zhe

@Vedant you mean the sandbox?

I dunno

pentavalentcarbon

3:43 PM

@Vedant It means exactly that, someone wants you to join the sandbox chat room.

Zhe

Take the plunge?

pentavalentcarbon

Ok, I'll be more specific and then I'll stop bugging you.

Were you looking for anything in particular? Specific language, a junior position, etc.

Zhe

@pentavalentcarbon No worries. This really isn't "bugging." Also, I'm just waiting for my code to compile :)

Yeah, I wanted a full-time position doing something interesting.

pentavalentcarbon

So that's the thing.

Vedant

@pentavalentcarbon whats the sandbox chatroom??

pentavalentcarbon

3:47 PM

@Vedant just click on it and find out, it's harmless...usually junk messages get sent there

I'm not sure I'm interested in most of the positions.

Zhe

@pentavalentcarbon I didn't get very far in the application process before I got an offer

pentavalentcarbon

Oh wow.

Zhe

I guess I would've sent out more applications if that hadn't worked out

But, luck

pentavalentcarbon

I guess, I'm pretty sure I could get a job. And I'm willing to be a junior dev.

Zhe

@pentavalentcarbon Are you an undergrad?

Once you get a job, it makes a lateral move easier, because "experience"

pentavalentcarbon

3:49 PM

ehhh.....I'm 2/3rds through a PhD in electronic structure theory and method development

Zhe

Ah, I see

But you're a theorist, so you probably have more coding experience than I did when I finished my PhD

pentavalentcarbon

I'm a Q-Chem developer and write a considerable amount of Python and C++ every day.

But I don't know if "the other side" will accept that.

Zhe

C++ and Python? You're set :)

On a day to day basis, I write C++, Java, Python, and a bunch of internal stuff

pentavalentcarbon

But I don't want to do web stuff, or "full stack" stuff, or even "data science" which is such an abused term. I'm not sure what I want.

Zhe

I work on backend stuff

Serving data to the frontend

It's pretty interesting

I would never want to do FE stuff professionally

pentavalentcarbon

3:55 PM

Well, the thing is, I don't know if my theoretical foundations in stuff like basic algorithms is strong enough.

I have a minor in CS from undergrad but that was a while ago and pretty limited IMO.

and I probably want to work for certain big-name places in Cambridge where that might be an issue

Zhe

Cambridge, UK?

Sorry for the confusion. I am in Cambridge, MA, US

pentavalentcarbon

noooo

yessss that one

orthocresol

Haha

pentavalentcarbon

not everyone here is European

Zhe

¯\_(ツ)_/¯

Wait, are you in school around here?

orthocresol

3:57 PM

There is an Oxford in Mississippi, btw.

pentavalentcarbon

It's ok. Not anymore. I'm from there and went to Northeastern for undergrad and would rather like to move back.

Zhe

Darn. I was going to say, if you're around, you should just come over to the office for lunch.

pentavalentcarbon

I'll be back again mid-December for vacation.

Zhe

Speaking of which, lunch time. I'll be around later if you have more questions. @pentavalentcarbon

pentavalentcarbon

Ok, thanks so much.

user228700

4:36 PM

Yo @DHMO: Was able to solve that semicircular disc problem with JR's help!

Zhe

5:06 PM

@pentavalentcarbon When you're here, ping me, and I'll give you a tour of our office.

M.A.R.

7

Q: Project Reduplication of Deduplication Has Begun!

While announcing the second iteration of the Stack Exchange quality project, I not-so-briefly alluded to a collaboration we're kicking off with the University Of Melbourne. The project presents some very interesting possibilities for us if their model validates as well as is hoped: Knowing ve...

discussion exact-duplicates se-quality-project

@Vedant That I have invited you to the sandbox chatroom.

Sandbox is where we test stuff.

I didn't really invite you. The invitation is automated when I moved your messages to Sandbox.

4 hours ago, by M.A.R.

→ 3 messages moved to Sandbox

pentavalentcarbon

I will, thank you.

M.A.R.

You're welcome

pentavalentcarbon

No, I'm not welcome, I'm @pentavalentcarbon.

M.A.R.

No, you're welcome. ಠ_ಠ

roscoe_casita

5:54 PM

Yar, I'm going to say that is a great feeling walking into a meeting with thesis /project teacher ... and your prepared. Walk out and they are happy... oh glorious day!

Zhe

@roscoe_casita w00t