mississippichem

I'm comfortable with aspects of non-relativistic QM. I am confused by QED. When I hear QFT though, I prefer to run and hide .

Moved to speculations. None of this is supported by established physics.

Huh? No, aromatics are more stable than their equivalent non-aromatic analogues. The planarity is what causes the delocalization and therefore the enhanced stability. Some aromatics are, in fact, not perfectly planar. However, these tend to not be as stable and display a lower "energy of aromaticity" which is the increase in bond dissociation enthalpy (or decrease in energy of formation, can't remember, sorry, the correlation is roughly the same either way) that is gained by being aromatic. I don't see how this follows, but yes. X-ray diffraction can be used to determine structural feature to a high degree of certainty if you can get a good crystal. There is also powder x-ray diffraction which I don't know much about. Do I understand this question properly?

Why does there need to be a logical verbal explanation? The English language was not designed with physics in mind. At the level of quantum mechanics or quantum theory, the mechanics and mathematics are quite far removed from our everyday experience. Things like tunneling, entanglement, and delocalization seem alien to us because we live in the world of large newtonian objects composed of many particles moving around at tiny fractions of c. The same things that seem alien to us are elementary conclusions drawn from QM, delocalization falls directly out of the uncertainty principle, and quantized energy levels fall straight from the eigenvalues of the Hamiltonian in the Schroedinger equation It is very anthropocentric to assume that the universe operates by principles that are easily understandable to humans. We have to use the mathematics to discuss these things where our everyday logic breaks down. I don't see the advantage to having a verbal explanation of quantum theory. Currently, I can use the math to predict the energy of orbitals in a large molecule, what I need is a better approximation method for the electron-electron repulsion function, not a nice piece of prose. A verbal explanation does me or any other person involved in physical sciences no good whatsoever. If you want to embark on the long journey of attempting to understanding quantum phenomena, no one ever really fully understands it , then read about differential equations, linear algebra, and operator theory along with a nice dose of Newton and Maxwell for background.

The rotational barrier around a [imath] \pi [/imath]-bond is very high. In the case of an aromatic like benzene, the symmetry (D6h) is such that the conjugated [imath] \pi [/imath]- system is able be delocalized over the whole ring. So all the electron density in the HOMO is evenly distributed above and below the plane of the ring. The bonds in benzene are stronger than they would've been in the theoretical cyclohexatriene, however they are rigid, meaning that their vibrational and rotational modes are quite limited. There is a phenomenon called ring puckering though, so the ring isn't totally rigid. No molecules are totally rigid. It's interesting to note that benzene can actually have a good bit more conformational freedom in high excited states

Affect...effect. Never could get it right. I frankly don't care enough to check in this informal setting.

I always worry about solvent carrying some toxic solute through the skin barrier. That's why DMSO can be so dangerous, whatever is dissolved in it is also crossing the barrier. I don't know what solutes acetone might carry through the skin, but I'd rather not find out the hard way. I use nitrile gloves for quick use of acetone, but I break out the butyl rubber if I'm going to be working with any significant quantity or doing something that is likely to get my hands covered. Safety first! Because: 1) You don't want to die 2) If you are in the USA, then you would rather die than pay the OSHA [Occupational Safety and Health Administration] fines, which are quite steep.

Quantum theory doesn't seem logical at all to those who don't understand the mathematics. The emphasis should be on whether or not a theory makes correct and testable predictions about reality. Quantum mechanics has given correct predictions many many many times, so what is the problem pantheory? I also do not understand the distinction between mathematics and logic. Math is nothing but the purest logic un-tainted by the semantics and word ambiguity of regular language.

Didn't you already have a thread on this. I'll give the same answer here. Oxygenated water is a complete marketing scam.

Are those "results" absorbances or extinction coefficients?

You would need a lot of sodium or potassium, thats for sure. Sounds like a tall tale to me. Nobody in their right mind keeps a lot of those things on hand in the lab anyway. The most sodium I've seen in one place is somewhere near five grams, in an organic lab of course.

escape_velocity: SM refers to statistical mechanics. I was trying to say that a list of chemistry exceptions pointless in the sense that its always a bit subjective, and not too useful. We could say that chromium and copper are the only two elements in the first row of the d-block that don't follow the ground state neutral charge orbital filing pattern, but really there is no exception here. There is a well known underlying cause for this phenomenon. It has to do with shielding, orbital penetration and all this coupled with a specific nuclear charge.

I agree. For example, here in the states there is currently a huge debate over whether we should raise taxes or cut entitlement programs. I say, what the hell is stopping us from doing both!? False dichotomies are evidently part for the course in political arguments.

I would also say that number 10 is not an exception as the d and f blocks comprise most of the periodic table and only VERY loosely follow a periodic trend of most common oxidation state. Crystal field effects almost always win out.

Water is water. As long as the pH is reasonably close to 7 and there are no toxic contaminants. The oxygen content of water makes no appreciable difference. Be careful, there are a lot of water health scams out there. Almost anyone advertising water that has some special health benefits is lying or just plain wrong.

Learn some theory first.

Yeah, these are more "rules of thumb" than actual rules. The only real rules in chemistry are the laws of physics and mathematics. In theory all chemistry can be derived out of QM and SM. However, no one knows how to solve an equation with that many variables or parameters.

You might look into borane clusters as well. I find the nido-borane clusters particularly intetesting.

Please! No one try to prepare barium azide outside of a professional or academic laboratory! You will lose a finger. Preparing cesium metal is also dangerous. Cesium comes in vacuum sealed ampules for a reason. Barium azide if both explosive and toxic. The preparation of cesium metal is best left to Sigma-Aldrich.

One could say so. There is no law against not conserving the number of bosons that I'm aware of.

I was a jazz musician before I got into chemistry. My creativity feels more liberated in the science world, and now I can afford to eat sometimes

spreken ze deutsch ajb? Ich habe Vokabular, aber wenig Grammatik

It does sound like the heating is driving off your waters of crystallization. I've never tried to melt sodium acetate before so I don't really know. Try dissolving it in water to make a saturated solution. Then recrystallize to regain your trihydrate. Wikipedia gives 46.4 g/ 100 mL at 20 oC, to give you an idea of what a saturated solution would be.

I know at least one person who was a poor undergrad chemistry student (made a lot of C's). He went on to get a decent job for a few years though and ended up getting into a PhD program probably based on an excellent letter of recommendation from a prominent employer. Recovery is possible but will require some blood, sweat, and tears. Put on your poker face and don't give up!

I am extremely pessimistic on this matter. However, I think it is still important to encourage people to have ideas...for the bright ones it can lead to a chain of events that might get them interested in pursuing science professionally. All of us had stupid questions/ideas at one point, I know I did. Not to say we should encourage rampant speculation without regard for math or experiment. I just mean that its good anyone is thinking about such questions at all these days when most of our youth would rather think of Lady Gaga.