mississippichem

Enthalpy measurements are made on the system. You could consider the internal energy, U, of a given product or reactant but all this involves fairly complicated physical chemistry/statistical mechanics and usually doesn't yield useful information (It's more an exercise in thermodynamic book keeping).

Good question. Remember that the total enthalpy of a reaction is the sum of the enthalpies of the elementary steps. Many reactions will involve elementary steps that are both endothermic and exothermic (good example: bond breaking is endothermic, bond forming is exothermic. Both bond making and breaking often happen in the same reaction). The total enthalpy of a reaction will always be net endothermic, net exothermic, or net zero. Look at wikipedia's image of a Born-Haber cycle for the formation of LiF. Also, a small side note. Your wording is a bit crunchy with the way you have defined endothermic. An endothermic reaction may not necessarily absorb heat from the surroundings. What we can say is that for all endothermic reactions [math] \Delta H [/math] is less than zero. The whole "getting hot/getting cold" way of thinking about this can lead to problems later in your understanding as temperature and heat are not the same thing. I'm being a bit picky here but usually picky leads itself to good understanding with respect to science. Be careful here though. The reaction probably never "goes exothermic then endothermic" as the kinetics of the reaction proceed. The energy of any collection of molecules in the system will display statistical behavior. Some molecules may already be in the product state while others are only just beginning the first elementary step. The take home message here is that enthalpy is a state-function and is not dependent on path. Some molecules may even take different kinetic paths to the products! EDIT: for wording

I second that. Carbon dioxide in water gives carbonic acid, a weak acid.

Try and learn some of the fundamental physics before you attempt any engineering with that physics. Not to discourage you. More young people need to be excited about science like you seem to be.

I imagine this will be a difficult separation unless you are okay with getting a mixture of Na and K hydroxides. I don't have any experience with the separation of Group I hydroxides but I'm getting the feeling that you may need to try and obtain KOH from elsewhere.

What is the square root of 17? Preferably to at least 26 decimal places.

insane_alien just said we have a unit named after him! That means he's a member of the scientific pantheon of people that have units named after them! That includes Newton, Farady, Coloumb, Gauss, Bohr, Dalton, Planck...all highly respected, if not worshiped, scientists. So rigney, why "poor Tesla"? He has received credit where credit was due. Not all the greats get a unit named after them.

A "single" bond is what's called a sigma-bond. They are more energetic than the pi-bonds that compose double and triple bonds. A double bond is one sigma-bond and one pi-bond. A triple bond is one sigma-bond and two pi-bonds.

Not at all. All the uncertainty principle says (with respect to position and momentum anyway) is that your uncertainty in momentum times your uncertainty in positions can never be less than [math] \hbar / 2 [/math]. Also, nothing about the second law of thermodynamics prevents the entropy of a system from decreasing. It happens all the time. It says that the entropy of the universe must never decrease in time. The entropy of a system may decrease but the entropy of the surroundings will increase by a greater amount! Look in your refrigerator, it is cold I hope. Put your hand behind it. What do you feel? The entropy of the air in your kitchen is being increased.

I think you hit the nail on the head with "we have not defined God" and when you say "interpreted as Pontius does". Doesn't that highlight the highly subjective nature of it all? That's why I can confidently say I am a hard atheist and still claim to have given the "god hypothesis" a fair chance. If you give the existence of god a hard unbiased, objective analysis of any kind, be it experimental, logic, or whatever; it will fail consistently. There is absolutely no reason to even begin to even speculate about whether or not a god exists because no one can even agree on the properties said god would have. once the door is opened to serious speculation about the existence of other things that have no empirical evidence the operational philosophy of objective science is out the window. It becomes logical for effort and time to be spent on exploring the existence of any highly speculative object. If god why not vampires? Seriously. They have about the same level of empirical, objective evidence for their existence, i.e. some highly superstitious old world people wrote about them! I honestly don't understand peoples' intellectual attachment to the existence of a god. Even though I used to be a Christian myself. It is certainly a powerful notion once it has been swallowed. I think people have a tendency to compartmentalize their thoughts between different subjects. This is unnecessary. It is my opinion that if one applies the way he thinks about unicorns or vampires to god he will certainly find the idea of the existence of a sentient god of any type to be unlikely or ridiculous.

Well, he died in 2007, but I'm still using this as a platform to glorify the accomplishments of one of my personal heros: Frank A. Cotton Cotton was a pioneer in the topic of chemical group theory, one of my favorite topics in the chemical sciences. Group theory provides modern chemists with a POWERFUL tool for analyzing electronic and vibrational spectroscopy. Cotton's contributions to cluster chemistry are also completely irreplaceable. Among some of his "stamp collecting" achievements, less impressive though still quite noteworthy, are the discovery of the quadruple bond. The interesting part is that he was able to predict the existence of higher order covalent d-d bonding in a time when the current paradigm was that they were unlikely to exist. This insight came from his intense understanding of quantum theory and group theory notions from pure mathematics. Any of his textbooks are pure gold. RIP Frank Cotton Sorry that I didn't meet the requirements of the OP but I couldn't resist. Boo! EDIT: to chastise Phi or All

So in my work I've had the pleasure of utilizing the Kramers-Kronig relations numerically to help solve certain problems. I understand the basics of how they are applied and their relationship to response functions. I'm looking for a deeper understanding in the general sense, both in the mathematics and some of the fundamental physics behind their application. If anyone is aware of any resources (review articles, textbooks, pdf's etc.) that could aid me in my plight I would be very grateful. Feel free to give materials that review this from either a mathematics, physics, or applied spectroscopy vantage point. I don't really care. I'm just very interested and want to further my knowledge in this seemingly rich topic. Thanks in advance to anyone who responds.

Gotta love beautiful LaTeX. Never gets old.

An experiment is not necessary. This is VERY established physics.

I must admit I do have a few uranium [oxide?] glass spheres that are fun to play with under a TLC UV hand bulb.

There is certainly some interesting actinoid chemistry. They are strange though and pretty much all we know about their chemistry is a collection of empirical facts. Physical chemistry people tend to hate them as they usually lead to computational nightmares. Those deeply buried l=3 orbitals do weird stuff. Relativistic methods also become important in those large nuclei.

What caused God? Your argument fails just as quickly as that of an atheist.

Chemistry ceases to be interesting somewhere around astatine, radon or francium. IIRC some people have prepared AtH in small quantities but who cares really ?

If you can answer this question completely you are a professional chemist . That's one thing to consider. There is also polarizability, steric effects, effective nuclear charge overpotentials required[redoc processes], kinetic and equilibrium considerations. In general "reactivity" is the thermodynamic tendency for something to undergo a chemical reaction with something else. It kind of looses meaning with the lack of another reactant IMO. I'm sure your answer will be sufficient or close if this is an elementary highschool chemistry course.

!Slightly off topic alert! For the record: Experts are nominated by members of the staff. The floor is then opened for those opposed to their nomination to object.

Same to ya. Nope, I read wikipedia and the good doctor's website. If you want to mail me a copy of the book, or buy me one, my address is... How do you know what anyone's intention was? How is it quantified? You're understanding of quantum entanglement is fundamentally flawed. Go read a physics book. Mathematical abstraction will be required. If you didn't like Minkowski space and it's lack of ontology...boy will you have fun with Hilbert space. *bold mine Again, how is this quantified? Burden of proof is on you. You're making the extraordinary claim. As a scientist I take that as a high honor, the materialist part. How are you not closed minded to my argument? Let's not pull out the "closed minded" card just yet. Save that one for later after you've exhausted your argument tool kit. I am in fact closed minded to science that offers no quantitative evidence. I refuse to even hear it. It is nonsense. Owl, you clearly have no understanding of physics and have a disdain for mainstream science. Why do you keep coming to a science site and trying to explain physics to physics people? What evidence compels you to the conclusion that the intention experiment has any merit at all? You've presented none so far.

Swansont's question and my question are both quite major problems to be dealt with. They are not marginal details. If you don't even have the workings of what might be considered an explanation already, why do you even advocate the electric universe/plasma cosmology shtuff? Do you think it's right because it sounds cool? I'm getting the feeling you've no logical grounding to base your opinion on. Not intended as an insult, sorry if it comes across that way. Imagine me speaking in a kind voice .

,or why no two astronomical bodies have been shown to repel each other. Does the sun have a net negative or positive charge? Why?

How can you say that? Our staff of mods and experts, as well as many of our very knowledgeable non-staffers almost always back up their assertions with references, and or somewhat detailed scientific logic/precedent. Has anyone on the staff ever made an assertion and then flashed their pedigree as their only evidence? Science is hard and requires expertise that comes from years of grueling education and training. I will readily admit that I'm probably the least of experts among experts (we have some absolute BEASTS of science here on the staff). Would you be willing to put your physics knowledge up against that of swansont or your mathematics knowledge up against ajb or Dr. Rocket? If not than you would be well advised to listen to their teaching and insight. I do.

I tend to agree with you more when you're being an arse. Stick to your skill set iNow.