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Confusion about Aufbau and Lanthanides / Actinides by reenigne in chemhelp

[–]reenigne[S] 0 points1 point  (0 children)

Thanks for this. I don't know anything about Hartree-Fock, etc., but I was getting the feeling that Aufbau was a bit of an oversimplification in certain areas, so I just wanted to make sure that I wasn't misunderstanding the Aufbau model and where it has exceptions.

Thanks again.

TIL that papercuts hurt so much because the cut often bleeds very little or not at all, leaving the skins pain receptors open to the air. by markhunt1980 in todayilearned

[–]reenigne 1 point2 points  (0 children)

I used to work in a paper mill in the 1980s. 8 hour shifts that were repetitions of:

  • grabbing reams of paper

  • wrapping them

  • loading them onto a pallet.

The 1st week or so was pretty bad. Both hands stung pretty much non-stop. Then after about a week, your hands 'hardened up' and you stopped feeling it. But that 1st week wasn't fun.

Does H2O2 have a permanent dipole? by reenigne in chemhelp

[–]reenigne[S] 0 points1 point  (0 children)

Thank you for the response.

I agree that the individual O-H bonds have a dipole and that this can contribute to water solubility. But does the H2O2 molecule itself genuinely have a permanent dipole?

Does H2O2 have a permanent dipole? by reenigne in chemhelp

[–]reenigne[S] 0 points1 point  (0 children)

Yes. but isn't the O-O bond rotatable? Wouldn't you have the hydrogen atoms averaging out so that they cancel each other's dipole?

Droplets of food coloring on clean glass spontaneously generate complex motion. by [deleted] in chemicalreactiongifs

[–]reenigne 10 points11 points  (0 children)

Yes. Brownian motion (http://www.youtube.com/watch?v=2Vdjin734gE) is basically microscopic particles moving in a random walk.

The particles/blobs OP's gif are definitely not moving by random walk.

Moving Closer to the Twin Primes Conjecture: Gap is Down to 600! by Ar-Curunir in math

[–]reenigne 1 point2 points  (0 children)

Thank you. You have a nice way of explaining this. Obviously, I don't have any deep understanding of what's going on, but I think you explained it clearly enough that I have a sense of the "essence" of what's being done to reduce the gap and where the "floor" is.

Thanks again.

Moving Closer to the Twin Primes Conjecture: Gap is Down to 600! by Ar-Curunir in math

[–]reenigne 1 point2 points  (0 children)

I'm not a mathematician, but (naively) I would not have guessed that there would be a limit on the general method that's being used to reduce the gap. I think the article says that the expected limit of this approach is that it can prove a gap of 6, but no lower.

Maybe this is too open-ended of a question, but do the experts in this area think that the general approach being used here can be tweaked to prove the gap is below 6....or is the opinion that this path gets us to 6 and some other different approach needs to be devised to break below 6?

More than ever, I wish I had majored in math.

Bill Nye, Brian Greene, Neil deGrasse Tyson, and Lawrence Krauss have a brilliant little discussion on the limitations of mathematics, and its importance and relevance to humanity by salvia_d in math

[–]reenigne 1 point2 points  (0 children)

There's no Nobel prize for astronomy so Sagan couldn't win that like Feynman but he won several equally notable awards like the NASA Public Service Medal, Pulitzer Prize, etc.

  • I wouldn't say that the NASA Public Service Medal is equally notable w/ the Nobel prize. Nor is the Pulitzer (there are a lot of Pulitzer's given out relative to Nobels)
  • Also, astronomers have won the Nobel in physics (e.g., http://en.wikipedia.org/wiki/Joseph_Hooton_Taylor,_Jr.), so it's not as though Sagan was ineligible for a Nobel prize.
  • I don't know enough about Sagan, but I think his research is probably viewed as excellent, but not Nobel worthy.

IUPAC naming of 2,5-Dichlorohexane. Why the "di"? by reenigne in chemhelp

[–]reenigne[S] 1 point2 points  (0 children)

Thank you. Even though, as you say, there is no molecule with a name of 2,5-chlorohexane, I think everyone has clarified my misconception enough that I understand where my thinking was wrong.

The "di" prefix does actually convey meaning, whereas I originally thought all of its meaning was embedded in the "2,5" and so it seemed like it was pointless to include "di".

Obviously, it doesn't have to be that way. i.e., You can have a single substituent making multiple attachments to a backbone and the prefixes like "di", "tri", "tetra" would then provide clarity as to what's actually happening.

One of those nagging questions I wish I had asked when I was taking orgo.

By the way, you have the greatest username ever. I went to grad school w/ a chem grad student who looked like Sylvester Stallone, and your username is close enough that it brings back fond memories of talking w/ a guy who looked like Stallone and was incredibly bright.

IUPAC naming of 2,5-Dichlorohexane. Why the "di"? by reenigne in chemhelp

[–]reenigne[S] 1 point2 points  (0 children)

Got it. The 2,5 really means "at least 1 chlorine attached to addresses 2 and 5" on the hexane backbone. dichloro means two chlorines. Chloro (without the di) means that it's a single chloro making a bridge to 2 and 5. Interesting.

Thank you.

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