The Periodic Table - 2018-03-04

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2:15 AM

Why does this website downvote every question i post?? — Jacob P.J 2 mins ago

new user annoyed by anon downvotes

7 hours later…

9:22 AM

@GaurangTandon It's a week

1

A: Theoretical comparison of critical constants of real gases

In essence regarding this problem $$T_\mathrm c \propto \frac{a}{b}$$ $$P_\mathrm c \propto \frac{a}{b^2}$$ $$V_\mathrm c \propto {b}$$ Values of $a$: $\ce{NH3} \to 4.225\ \mathrm{l^2\ bar/mol^2}$ $\ce{CO2} \to 3.640\ \mathrm{l^2\ bar/mol^2}$ $\ce{H2O} \to 5.536\ \mathrm{l^2\ bar/mol^2}$. ...

9:38 AM

@AvnishKabaj yep, I changed my mind :P See, the trend is so brilliant, I was hoping for some explanation behind it. I admit I might be hopeless in hoping some explanation, but still. I'll hope. Within a month I'll put a bounty on that question and hope that someone comes along and writes an explanation based on intermolecular forces or any other theory

9:51 AM

@GaurangTandon Ok IMO it's just an algebraic equation. But you never know

4 hours later…

1:28 PM

@GaurangTandon I asked Secret, he said that Soumik Das' answer is correct except one minor error. So should I award him the bounty and also type his answer in a more neater way as a new answer?

Also, @GaurangTandon Pleasee help me enable chem jax.

@Abcd what's the logic behind the chlorination question which you asked yesterday?

@AvnishKabaj I will ask that today on SE.

@AvnishKabaj Avatar Shiny, why did you change your username? Avatar Shiny sounded better than Avnish indeed.

@Abcd My votes per answer Nobel paper begs to differ

@AvnishKabaj I didn't get you

Gimme a sec

@Abcd

yesterday, by Avnish Kabaj

After performing a very scientinfic exapariment I have come to the conclusion that changing your Avatar from hand drawn smiley to the emote and name from 'Avatar Shiny' to an equally fake but real sounding name leads to an increment in the upvotes to answer ratio by a phenomenal amount. Including previously deleted answers the ratio was .4 upvotes per answer pre profile update, post profile update the ratio is 7.33 upvotes per answer.

My next pseudonym will be Krishna Ayyavat

1:37 PM

...

correlation != causation

...

Last night dream, there's a lot of people (including me) in a wooden house. In one of the room, there is fluorine leaking from a fume cupboard pipping, and causing the whole group to be coughing as it give off a pungent smell. They must obtain the antidote from the host else die when the bones get calcified by the F- ions (one boy already has his arm gone, exposing a piece of bone that gradually became sharper and more worn as the CaF2 conversion makes it brittle and shatter to dust

I think the dream somehow mixed up HF with F2

also I don't recall whether CaF2 is brittle compared to Ca3(PO4)2

@Secret I don't understand how someone can get so many weird dreams :/

3

@Secret Shouldn't yesterday's event be reported to a Moderator?

what yesterday event?

1:54 PM

@Secret Also, did you figure out that AlCl3 dimer thing? Do you plan to answer it?

9 mins ago, by Abcd

@Secret Shouldn't yesterday's event be reported to a Moderator?

Never mind, I am being too harsh^ .. Many people make such mistakes when they are new to the site.

@Abcd I see

@Abcd Nah, I had a more detailed look again, and I don't think martin's answer actually address the two angles you are interested in. Bents rule will explain the two bridge bond angles, but not that 118 angle

James answer address the question for the solid state case, but I am not sure if he had addressed the gaseous case

Michael Harding

2:13 PM

I'm an undergraduate doing a small project on biodiesel, anyone have any ideas for directions of research?

@Abcd you may report it , your choice , but as you say , I was new , I don't really use the main sites now.

@Tanuj I said "never mind" :-). Chill!

Yea , cool. It was childish of me to be doing that. Like I'm not going to be paid for more rep

2:27 PM

@Abcd he'll automatically get half the bounty even if you don't award him yourself

@Secret I think by "Martin" you're referring to "James Gaidis"?

1 hour ago, by Abcd

@GaurangTandon I asked Secret, he said that Soumik Das' answer is correct except one minor error. So should I award him the bounty and also type his answer in a more neater way as a new answer?

" also type his answer in a more neater way as a new answer?" @GaurangTandon

2:47 PM

@Abcd what do you mean?

@GaurangTandon should i present his answer in a better way

@Abcd I edited his post's grammar myself, so I am not sure if the source of your confusion lies in its grammar; that said, i'm not sure how you can post a new answer without inadvertently saying everything he said and thereby falling into plagiarism

if there's one minute error

just comment to him

what is that error anyway?

> For 4-fluorophenol, the +R effect of F is stronger than -I effect.

I effect is stronger than R effect for all halogens. Therefore all halogens are deactivating. — Abcd 23 hours ago

@GaurangTandon ^^

also by martin, I mean this:

24

A: Why is BCl3 a monomer whereas AlCl3 exists as a dimer?

Introduction The bonding situation in $\ce{(AlCl3)2}$ and $\ce{(BCl3)2}$ is nothing trivial and the reason why aluminium chloride forms dimers, while boron trichloride does not, cannot only be attributed to size. In order to understand this phenomenon we need to look at both, the monomers and t...

@NilayGhosh that answer actually fully answers this question. — Stian Yttervik Oct 17 '17 at 10:04

@StianYttervik I think Martin's calculation does not really address why the other Cl-Al-Cl angle is 118. Sure, bent's rule will explain why the inner Cl-Al-Cl is 79 < tetrahedral, it does not explain why the other angle is larger than tetrahedral (and using bent's rule there will mean those Cl will have more negative formal charges than the bridging Cl) — Secret 21 hours ago

2:52 PM

@Secret oh oh that's definitely wrong

other than that, everything else is fine

@GaurangTandon Yup, he (Soumik) has mentioned that in his answer

ok I also commented in him to add the pressure

hopefully he'll reply back

@GaurangTandon pressure?

@Abcd you commented 23hrs ago he still hasn't replied

@Secret that question just blew my mind

@Abcd if you don't i'll ask it tomo eve i'm really really waiting for the answer ;)

2:59 PM

I second that

3:27 PM

@Secret

Ok, I think the word "comparable" is probably more suitable. — Soumik Das 28 secs ago

what say?

i disagree with him, but I don't have anything suitable to tell him either

*suitable = scientific evidence or facts

well its a bit vague, cause comparable only means the difference between I effect and M effect is small (abcd can confirm that), but it does not say which one is stronger

abcd did point out that F is the weakest deactivating group

yep that's true i'll add another comment there

@Secret i think it's iodine instead (source)

3:50 PM

@GaurangTandon No, my source = March's Advanced Organic Chemistry+ Solomon Frhyle cc: @Secret

4:02 PM

@GaurangTandon Night = 4 am or 3 am cc: @AvnishKabaj

4:23 PM

1

Q: pKa of different Butanone Sites

There are many interesting posts about ketone deprotonation, but browsing them I am unable to answer the following question(s) Ref: "Which enolate of butanone is more stable?", "Regioselective enolate formation" From what I can tell, deprotonation of the central hydrogen leads to the more th...

organic-chemistry acid-base carbonyl-compounds stability

@Abcd can you give page numbers please?

4 hours later…

8:38 PM

user image

Why is this molecule chiral? ..even if the 2 rings were perpendicular to each other, it'll be symmetric?

@Rick Yes

@Rick There's a plane passing through the first ring and dividing the 2nd ring into 2 parts

@Abcd Yes

There's a plane of symmetry

@Rick SO its NOT chiral

8:54 PM

Which is what I though too...but the answer key says it is :/

@Rick Take it from me, your answer key is WRONG.

I confirmed with my notes from March's Advanced organic chemistry.

And with my FIITJEE notes

9:24 PM

I suppose so..

9:38 PM

Can someone confirm this?

..also why does dehydration of butan-1-ol with conc H2SO4 give but-2-ene?

I thought it should give but-1-ene because there's only 1 H adjacent to the -OH to remove H2O?

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The Periodic Table

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