mississippichem

Yes, now you're thinking chemically! Just remember that these interactions are WAY stronger than gravity.

I've thought about this before. Great minds think alike . I think the idea is to find a viable synthetic route and to make sure one is feasible before the inevitable complications of enantiomeric catalysts and such are employed. A good organic chemist will be able to forsee these diastereometric complications and adjust synthetic methods accordingly. For example, if we have reaction that we know will produce a "useless" diastereomer, then before the next step we'll just selectively re-crystallize and drive the "bad-diastereomer" out preemptively. The last thing an organic chemist needs is a yield robbing side product. I'm really into inorganic and physical chemistry so even though my answer works, I'm sure Hypervalent_iodine or Horza2002 might give more insightful answers.

It is noteworthy that my copy of March's Adnaved Organic Chemistry, an organic reactions reference book that I highly recommend; has almost an entire section devoted to hypervalent iodine reagents. Hypervalent_iodine [the person], it seems you chose your username wisely!

Actually quite the opposite. Water generally dissolves things that have discrete ions, as well as other polar substances. The water molecules can align itself to solvate positive or negative ions. The sum of the positive charges on the hydrogens is equal in magnitude of the charge on the oxygen atom. Water molecules form a shell around ions in solution accordingly: Don't take the picture too literally though, there is really more organization than that but the system is dynamic and constantly shifting, bending and re-coordinating. The water molecules bind the ions strongly, but these interactions are still very weak compared to any covalent bond.

Well, everything is soluble in everything to some degree, the devil is in the details. Your interpretation is correct enough though. I think you've caught the jest.

I'm not sure I really understand the original question. The reaction of [ce]H_{2}[/ce] with [ce]O_{2}[/ce] in the gas phase is not an ionic reaction. It proceeds by a radical mechanism, that actually has very complex, and not too well understood kinetics. The equation you have pictured doesn't make sense, by "[ce]H[/ce]" do you mean [ce]H_{2}[/ce]? As for the second part, which ions react is all governed by an equilibrium. Mix two water soluble ionic compounds together in water and you get no reaction if none of the possible combinations of ions are insoluble. Those percipitations are an equilibrium processes and can be predicted with an equilibrium expression. Maybe try to reword the question.

It's usually some little dim-whit deviant trying to get his post-count up to start a rant in ethics or politics. They usually get sacked by an admin or mod eventually.

Water's high boiling point is the result of strong dipole-dipole interactions and in turn hydrogen bonding. The above diagram shows the oxidation states and energetics between various common inorganic nitrogen compounds. This is expressed in terms of volts because we are looking at an electrochemical series here, but don't worry too much about that. The important concept is, that we can "reduce" or "oxidize" nitrogen and there are energetic considerations to deal with. Molecular [ce] N_{2} [/ce] is the most stable species on the diagram, and as a result, transforming any of the other nitrogen compounds into [ce] N_{2} [/ce] will release energy. The further away on the diagram, the more energy released. Don't get confused by the [math] \pm [/math] sign convention either. That just has to do with the electrochemical aspect of the diagram. I posted this diagram so you could see the various energetic distances between these species and compare qualitatively.

It also allows you to pick out the quadratic formula easily, a method that always gives you a solution: [math] x= \frac{-b\pm\sqrt{b^{2}-4ac}}{2a} [/math]

That was my initial reaction as well. Evidently it passivates bulk iron but will react with iron powder. That's what I read in a textbook, I've never seen it.

This sounds like homework. We don't give homework answers but we do give homework help. It depends on what temperature, depending on the temperature and concentration of the acid you will either get Iron(II) nitrate or Iron(III) nitrate, along with nitric oxide or nitrogen dioxide. Much of the nitrogen oxide redox chemistry is temperature dependent. You should be able to work it out from here, just set up your reactants and products, then balance iron atoms, nitrogen atoms, hydrogen atoms and oxygen atoms; in that specific order. That's not the only way but that always works well for me; hydrogens and oxygens last, metals first.

A quick google search of "HHO generator" shows a bunch of charlatans trying to sell devices that electrolyze water to hydrogen for a net energy gain. If that's what you mean by "HHO generator", it can't be done. Yes, you can electrolyze water to hydrogen but it will cost you more energy than you can get by oxidizing the hydrogen, guaranteed. When hydrogen is electrolyzed industrially sulfuric acid is usually used because the [ce]SO_{4}^{2-}[/ce] [sulfate] ion won't compete with the [ce] OH^{-} [/ce] [hydroxide] ion to be oxidized. [ce] NaOH [/ce] can also be used for similar reasons.

True, I should have said negative entropy change. Good catch

Once you have dealt with the percent composition, it appears you have a freezing point depression problem on your hands: [math] \Delta T_{f}=k_{f}mi [/math] Remember that [math] k_{f} [/math] for water is [math] 1.853 K \cdot kg \cdot mol^{-1} [/math]

I used to wonder the same thing. Next thing you know I have a degree in chemistry Yes that is quite a tall order. I've spent the last four years of my life studying such things, and will probably spend the next six becoming an authority. "single bonds" and "double bonds" are really just approximations we use to describe molecular orbitals between nuclei. Each bond type roughly corresponds to a certain symmetry of wave functions. The most concrete thing about bond order is that like Horza2002 said: The full descriptions of bonds is quite cumbersome and the nomenclature goes something like this: [math] 2p2p\pi E_{2g} [/math] The above describes what many would call a double bond between two carbon atoms.

There are many examples but few are intuitive at face value. That's where the math comes in. Since this thread is about spin, I'll use spin as an example. There are some chemical reactions that are "spin-controlled". If you observe said reaction and time everything meticulously, you can do what's called a kinetic study. Kinetics is the study of the rates of chemical reactions and how these reactions occur at the most fundamental level. There are some reactions, that once you do all the kinetics math you will see the that rate determining step (the "slowest" step that will determine how fast this can happen") is a spin flip. Two electrons that have the same spin can't be paired. A chemical bond contains two electrons that are spin paired. After doing all the math it is observed that these molecules react with each other almost as fast as they can collide with each other in solution minus some very small unit of time. This unit of time in some reactions happens to coincide with the approximate time required for a spin flip to occur. Another, perhaps, even more familiar [but less direct in my opinion] example is magnetism. All the different types of magnetism: ferromagnetism, paramagentism, diamagnetism, ferrimagnetism and the like are all spin related phenomena.

If you work out the orbital configurations for a ring of six carbon atoms (each one having one attached hydrogen), at the end you'll end up with six left over orbitals that are all degenerate and orthogonal to the plane of the hexagonal ring. Because they are degenerate [same energy] they can add together in a linear fashion (remember these orbitals are differential solutions to an equation). Then you end up with even probability distribution of electrons on both faces of the ring. Here is a rendering of the first few [math] \pi [/math]-energy levels of benzene, the orbitals that are depicted horizontally side by side are degenerate: Valence bond theory predicts alternating single and double bonds for benzene, but the molecular orbital treatment shows that it ain't so, and really all the bonds are intermediate between single and double bonds. The word "bond" has less and less real meaning as molecules are analyzed quantum mechanically. The formal definition of aromatic is any collection of atoms that are bonded together in a planar ring containing 4n+2 electrons [where n is an integer] that are not involved in a [math] \sigma [/math]-bond. The word "aromatic" is an artifact of a very old nomenclature system. All aromatic systems have somewhat "delocalized" [math] \pi [/math]-systems; delocalized is sometimes considered a bad word though because technically, all fermions are delocalized to some extent as per Heisenberg. It just so happens though that many aromatic compounds do have a sweet "aromatic" smell and also happen to be evaporated easily (low boiling point, high vapor-pressure at STP)

Did somebody say my name? Yes, the advent of quantum mechanics has done wonders for the world of chemistry. Before molecular orbital theory, chemistry was stuck with what was called "valence bond theory" which worked quite well for determining the basic geometries of many molecules, but was very lacking with reference to spectroscopy, and other aspects of the observed behavior of electrons in molecules. Many chemical reactions are in fact the result of electrons reaching certain excited states that allow the formation of new orbitals between molecules i.e. new bonds. My area of interest in chemistry is mostly in the department of physical and quantum chemistry. Now days it's possible to predict expected spectral readings or even reaction outcomes sometimes based on the quantum mechanical properties of molecules. It's funny because there is both a journal of molecular physics and a journal of physical chemistry and both really deal with the same subject matter to a large degree. I read them both. I think it is fairly safe to say that quantum theory effects chemistry just as much as physics, especially in these modern times where computational chemistry is on the rise. Math and computer simulations are cheaper than "wet" chemistry once the initial investment is paid off. If you're looking for a good example that is easily accessible, do some reading about electron resonance in aromatic systems [namely benzene]. Classical atomic physics had absolutely no valid explanation for the observed spectroscopy, structure, and reactivity of benzene and other aromatic compounds. Valence bond theory was also not at all satisfactory for the observed behavior of most transition metal chemistry. There is currently a large movement within physical chemistry to make better relativistic corrections to our current quantum mechanical models of molecules involving elements with very large nuclei, something I thought was worth mentioning.

This question gets a lot of students. The answer is quite counter intuitive, but there are several ways to analyze this. Hydrofluoric acid is a weak acid, unlike the other binary halo-acids. The "best" reason is the that the aqueous solvation shell that forms around a dissociated fluoride ion is highly organized; so much so that it creates a positive negative [math] \Delta S [/math] [change in entropy term] for the thermodynamics of the solubility equilibrium. Positive changes in entropy are not thermodynamically favored. Also, HF in concentrated solution can begin to polymerize somewhat as a result of very strong hydrogen bonding interactions: [ce][HFHFHF]_{n}[/ce]. EDIT: Negative entropy change, not positive.

I love animals. I have three dogs and an iguana all of whose company I enjoy on a daily basis. However, I also love steak, pork, fish and the like. If all humans were to stop eating meat today; other carnivorous animals would continue to consume herbivores. I don't see a moral dilemma here at all, as long as we take care to minimize the animals' suffering as we kill them. Really though, other carnivores don't even do that much [ever seen a house cat torture a mouse?]. It's just the nature of living things. I can eat a cow, but a tiger can eat me! I also enjoy hunting and fishing, but my policy is that I only kill what I will eat. I believe that killing animals for reasons other than self defense, food, or sound science is unethical.

I'm not sure in this particular case, but fluorine is often the "odd man out" of the halogens. Fluorine's huge electronegativity and strong electron affinity make it very hard to polarize which actually makes it quite a poor nucleophile. This is a bit counter intuitive as fluorine is often thought of as a very reactive reagent. It is, but it seems to prefer reacting through homolytic [radical] mechanisms. adding a fluorine atom to organics usually requires a specialized fluorinating agent. The trick with organofluorine chemistry is to find a reagent that will react but is still somewhat selective. Some reagents that will add fluorine go way overboard and fluorinate everything. The quest for mild yet selective fluorinating agents is an ongoing investigation though there are some good ones out there already.

In short, the Pauli exclusion principle. -for n=1, there is only an s-orbital -for n=2 there is an s-orbital and a p-orbital The pattern continues: 1| s 2| s p 3| s p d 4| s p d f ...and so on. Every orbital can hold two electrons. The angular momentum number "[math] \ell [/math]" defines which type of orbital, and for every level n, the allowed [math] \ell [/math] numbers range from 0 to n-1. So for an s-orbital [math] \ell=0 [/math], for a p-orbital [math] \ell=1 [/math] and so on. You can use this to generate that pattern shown above. Then all you have to know is that s-orbitals are non-degenerate and come by themselves, p-orbitals are triply degenerate and come in groups of 3, d-orbitals come in groups of 5, and f-orbitals come in groups of 7. So for example, a set of d-orbitals can hold 10 electrons. The Wikipedia article is a good place to inquire further: Wikipedia: Electron Configuration

This most definitely involves intermolecular forces! What kind of approach are you looking for? Or maybe I should say, how far are you looking to dig? Qualitative observation, quantitative observation, or a more rigorous treatment?

I can't speak much to the mechanical generation of electric potential, but I can the chemical: In a battery there are two different cells, each containing some chemical dissolved (sometimes more like suspended) in a strong electrolyte solution. The chemicals in one cell have this inherent tendency to donate electrons to the chemicals in the other cell. It's all relative though, substance "A" may donate electrons to substance "B" but receive electrons from substance "C". This is called an oxidation/reduction potential. Normally, if you were to mix these chemicals you would just get a pretty energetic reaction. In the battery, they cannot mix, and the electrons are forced through the wire. So in short, the potential is generated by "redirecting" an oxidation/reduction potential through a wire. Wikipedia: Electrochemical Cell

I'm an athiest. But I'm a Christian on Christmas, I'm Jewish on Hanukka, and Muslim on Ramadan as long as there are days to be had off work and an excuse to enjoy a large meal and or drinks.