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mississippichem

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Everything posted by mississippichem

  1. Lemur, What you may call being defensive is just an attempt to make it clear that there is no qualitative model that describes with complete accuracy any system. If someone says that a ball is red, that may be true, but it is not precise. A precise, and in my opinion more scientific and falsifiable, statement is that the ball's color is 760 nm-red. Then I can directly measure the frequency of the light in question and definitively conclude as to whether or not the statement is accurate. If the statement is inaccurate, I can quantify this error and say that for example that the predicted frequency is 5% wrong. This is just a simple example. When examining the finer points of our natural world like quantum mechanics or general relativity, things that our outside our everyday intuition of "medium-sized-slowly-moving" macro objects, it becomes even more crucial that definitive statements are only made quantitatively. Sometimes there simply are not words to describe the phenomena that are occurring. We have no word for something that has some particle-like nature but also displays wave-like properties. So we say that the electron orbitals are solutions to a differential equation: [math]i\hbar\frac{\partial}{\partial t} \Psi = \hat H \Psi[/math] You may not know what all this means; that's alright, don't feel bad. Relatively few have enough math knowledge to understand the complete implications of the above equation. However, just because you do not understand doesn't mean there must be a better way to describe it. Thus far, any qualitative explanation that has been offered to explain the behavior o atomic electrons has been flawed in some crucial way, namely violating the uncertainty principle. That's just how it is. Swansont didn't write the laws of nature, he just understands them better than many here on the forum. Give him a break, eh? He's just trying to ensure that the correct information bounces around the forum. We must be alert and, somewhat defensive even, when talking about issues that are so laden with such common logical errors. One wrong phrase can drastically alter someones perception and in turn cause them to spread falsities. Bad information seems to travel very fast; faster than good information for some reason. I'm a private tutor for college chemistry students and I always take great care not to give the wrong impression about a finesse concept. Some may call me uptight about it, but I frankly don't care. If you are a student of mississippichem you will be instructed precisely and correctly, I think that is something to be proud of.
  2. Stuff doesn't stop dissolving because there is no room left for solutes. It's that there is not much room left to form adequate hydration shells. Most metal ions in water have an octahedrally cited shell of six water molecules coordinated to the central ion. Some metals can take hydration shells of up to 12 water molecules. There are other considerations as well, like the ionic radius of the metal which in turn has an effect on the dielectric properties of the solution. This can go on to be a limiter to the density of charge that can be built up in solution. You will notice, however, that more salt can be dissolved in hot water than cold. Proving that there is in act some room left over in saturated solution at room temperature. Solution and colligative properties are often hard to extrapolate out far because, though seemingly simple, they are often highly non-linear. At high concentrations many solutions of salts form a plethora of colloidal forms and partially separated phases that are just down right hard to predict unless one is familiar with that compound. Not to mention that the equilibrium calculated concentration of a solute becomes less and less accurate as the concentration approaches saturation levels. [ce] \gamma [/ce]-coefficients must be accounted for as well as the kinetics of the possible colloidal phases. Short answer: water doesn't turn into a solid because, though the hydration shells are ordered, they are not ordered enough to allow water molecules to be low entropy enough to stay in a crystal. Plus, at room temperature and pressure water just can't exist as a solid, but that answer isn't very satisfying is it?
  3. Have you ever done an acid/base titration before?
  4. I play bass; classical and other. The only songs where I can seem to remember every detail are the songs that I've played a million or so times. However, I think at that point it's just become "muscle memory" and is more akin to typing than playing a song.
  5. Not to mention that if the reaction gets out of hand half way through you'll have an exploding beaker full of oxidizing acid and flammable organic. That's all four chemical hazards at once (acid/base, flammable, explosive, re-dox).
  6. The theoretical model and "mental picture" of a theory come from the math. The math describes the observed events precisely. But no prose or conceptual language can describe a theory as well and unambiguously as the math can.
  7. Sort of. I would prefer to say that the photon transfers to the electron sufficient energy to exceed the ionization energy requirement for that electron. I don't know how far the knocking analogy goes. Atoms become anions [negatively charged] because full orbitals are lower in energy than "close-to-full" orbitals. For example Fluorine lacks one electron from having a complete [math] 2p^{6} [/math] subshell. It is energetically more favorable to take on a -1 negative charge than not in this case. Empty orbitals and half-filled orbital sets tend to be favored as well. There is really no sound analogy with the classical world. A classical body's angular momentum is given by [math]\vec{r} \times m\vec{v}[/math]. In quantum mechanics angular momentum is an operator on a wave function serving to define the shape of that wave function. So we use the quantum number [math] \ell [/math] to talk about the angular momentum of electrons in atoms. For an s-orbital in a hydrogen like atom [math] \ell=0 [/math]. For a p-orbital, [math] \ell=1[/math] and so on. The derivation of "[math] \ell [/math]" is somewhat complicated.
  8. I've read the Bible, cover to cover. I was strongly Christian during my childhood. The more I studied it, the more I found it to be lacking in rigor. At the same time I was beginning to read about simple science stuff. The more I studied science, the more I found it to be an almost infinite well of rigor. I lost my Christianity slowly, axiom by axoim, until I realized that once enough axioms have been removed the building collapses and Christianity no longer makes any sense. I've also read many excerpts from the Quaran and Bhagavad Gita; I found them to be equally lacking. I don't see why everyone needs to believe in something spiritual. I don't believe in anything supernatural or spiritual at all; literally none of it. I find my own paradigm to be very intellectually freeing and internally consistent. It's actually very satisfying and fulfilling to know that you are the master of your own destiny. I know that all my successes are from my merit and all my failures are my fault. I sleep very well at night.
  9. I think they should coexist in the sense that theologians and scientist should not be violent or actively disrespectful toward each other. But when there is an intellectual disagreement then there is just an intellectual disagreement. I would not, however, be one to give credibility to an argument that I thought was unsound in the name of respect or peace. I have no problem with theology as long as it stays "theological" and doesn't attempt to challenge empirical science with philosophical noodling or hand waiving. I do think that two opponents can argue vigorously without being disrespectful though.
  10. John Cuthber, hypervalent_iodine Am I the only one who noticed that the OP poster's username is also indicative of an amphetamine synthesis?
  11. Well, the observed color of the emission that follows the nucleus becoming excited would probably be "gamma-colored" i.e. a much higher frequency of light than humans [or any other creatures for that matter I safely assume] can see. Nuclear transitions are really high energy when compared the electron transitions which corresponds to much higher frequencies.
  12. seasnake, You should do some reading on dimensional analysis before you try to improve on Einstein's GR equations. For example, velocity is defined in units of displacement per time [e.g. meters/second]. If find a value for velocity that is in units of, lets say, newtons per meter [N/m], then I've absolutely done something wrong; no matter how I want to look at it.
  13. Well I couldn't find a true flourescence spectrum of [math]\beta[/math]-carotene, but this UV-vis spectrum shows that there is some absorbance in the near UV. Assuming a typical stokes shift for linear conjugated poly-enes; there should be some fluorescence in the "violet-blue-green" area of the spectrum. UV-vis: beta carotene However I don't know anything about the quantum yield for carotenes, so i don't know if the fluorescence will be intense enough to be visible.
  14. The phosphoanhydride bonds of ATP are kinetically stable in water but the hydrolysis of these bonds is exothermic and yields a lot of energy per mole. Other anhydrides may yield more energy per mole but are not kinetically stable enough to exist in aqueous solution which is an obvious requirement. ATP can also be hydrolyzed twice to ADP and AMP. This offers the advantage of allowing two hydrolysese to occur on one molecule of "fuel" which is important since biological aqueous solutions are already so close to saturation. I think it's also convenient that adenosine is a nucleoside incorporated in DNA; killing two birds with one stone so to speak.
  15. The predicted angular momentum of the electron was wrong for one thing.
  16. It's easier to surpass logic and reason with a video by evoking emotions in the viewers. 911 was a traumatic experience for us Americans, and it's easy to get people suspicious over an event surrounded by so much hype.
  17. Do you know the extraction process... I mean generally. I know you're not a chemical engineer.
  18. Yes, as John Cuthber said, you are straying dangerously close to an illicit synthesis. If you can show where this is part of a legitimate synthesis or experiment that would be appreciated.
  19. Dom, As Fuzzwood pointed out, your reaction equation is out of balance. Here is the balanced equation: [ce]AlCl_{3} + 3NaOH -> Al(OH)_{3} + 3NaCl[/ce] Now try to rework it and see what happens.
  20. Show how far you can get in the problem before you get stuck. I'll help pull you out of the rut.
  21. You're not doing much to help your cause by calling atheists sad god haters.
  22. Nitroglycerine is an organo nitrate compound. Nitric acid is just a nitrate anion with an extra proton. The abundance of [ce]R-CONO_2[/ce] linakges in nitroglycerine is what makes it unstable and therefore explosive. Nitric acid just doesn't have that type of structure.
  23. true, a five year old can do his reaction. It's just iron oxide (rust) and aluminum chips maybe with a magnesium fuse. Some people talk about "nano-thermite" being in the WTC's but that's just "really finely ground thermite". Sailt 2, see post #4 This issue has already been addressed. The iron doesn't have to melt or burn. It only has to undergo a phase transition in order for the building to collapse.
  24. Some helium compounds have been observed in the gas phase. They're all metastable [very short lived] and most are just Van der Waals complexes. Compounds that don't have any true LCAO bonds, but just temporary dipoles that cause a brief, weak interaction. It has been postulated that [ce] HeH^+ [/ce] has a true bond, but it is also very short lived. This though isn't even be a negatively charged helium species though. All helium ions are unstable, the anions [negative] more so than the cations [positive]. No idea about the black hole thing...ask Leonard Susskind or Stephen Hawking. Might be unicorn speculation though.
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