mississippichem

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Difluorine has a fully occupied [math] 2p \pi [/math] orbital which makes the bond short like a double bond. However, difluorine also has a fully occupied [math]2p \pi^{*} [/math] antibonding orbital. So the next effect is a bond that is about as energetic as a typical single bond but about as long as a typical double bond. Another, more classical, way to look at this is there is a lot of electron-electron repulsion going on between the six sets of lone pairs between the two fluorine atoms. Each fluorine center is also highly electronegative, equally electronegative. However, this might be only trivially correct; the molecular orbital description above is more acceptable.

from wikipedia [article:Entropy (order and disorder)]: The only requirement on the sign of the [math]\Delta S[/math] term is that: [math]\Delta S_{universe}>0[/math] [math]\Delta S_{system}+\Delta S_{surroundings}>0[/math] The entropy of the system [inside the refrigerator] must decrease if the above inequality or the Clausius Inequality is to hold. The heat flux leaving the system is accounted for by [math] (\Delta S_{surroundings}) [/math]; you've incorrectly defined the system. The process you described with a negative [math]dQ[/math] and [math] dT[/math] for the system along with a positive [math] dS [/math] for the system is highly improbable

Cypress, how do you reconcile that with: [math] dU=TdS-PdV [/math] or [math] dS = \frac{\delta Q}{T} \! [/math] About volumetric contraction: I would treat the refrigerator as a constant volume system. Correct me if I'm not understanding your treatment of the system as a non-constant volume system. EDIT: It's worth adding that biological systems exist in a state of perpetual dynamic non-equilibrium. I don't know if anyone here knows any non-equilibrium thermodynamics. I honestly know very little.

C-C is comprised of one [math] \sigma [/math] bond. C=C is comprised of one [math] \sigma [/math] and one [math]\pi[/math] bond. C=C is more energetic and therefore a stronger bond and shorter. Remember, [math] \pi [/math] bonds are made by side on overlap between p or d orbitals, while [math] \sigma [/math] bonds are made by overlap between two s-orbitals, two p-orbitals (head on overlap), or an (s and p)/(s and d) (head on overlap). C=C is also a four electron bond while C-C is a two electron bond.

You're on the right track. The amount of orbital overlap between the corresponding atomic orbitals to form a set of molecular orbitals is also a factor. Orbitals of similar shape, size, and energy overlap well and form strong short bonds. There are also symmetry considerations, but they don't matter much unless you are looking for an advanced treatment of the system.

Gibbs in related to the other thermodynamic state variables by: [math]\Delta G^{o}={\Delta H^{o}}-{{T}\Delta S^{o}}[/math] Gibbs energy is related to equilibrium by: [math] \ln \left( {\frac{{K_2 }}{{K_1 }}} \right) = \frac{{ \Delta H^{o} }}{R}\left( {\frac{1}{{T_1 }} - \frac{1}{{T_2 }}} \right) [/math] and [math] \Delta G^\circ = -RT(\ln K) [/math] Enzymes are catalysts, they just lower the activation barrier for a given reaction. This just lowers the "energy hump" on the reaction coordinate. No effect on equilibrium though. Activation barriers can be expressed in Gibbs, but those are Gibbs activation energies; different from the overall Gibbs energy for a reaction (the above math). It's easy to get confused about enzymes affecting equilibrium, they don't though. Gibbs energy of activation is not equilibrium dependent: [math]k = \frac{k_BT}{h}e^{-\frac{\Delta G_{act}}{RT}} [/math] where the lower case k is the rate constant.

The ideal bunsen burner flame should look like the one pictured on the left. Two distinct cones, both blue but one really bright.

I Looked back through the related threads. I guess I don't understand. Why no water if no humidity will be produced?

Thanks. It's a good thing you didn't ban me Cap'n...You wouldn't like me when I'm angry!

I've tried to login to the chat today and yesterday. I keep getting "server not found" error messages. Is this a problem on my end or is anyone else having this problem? EDIT: It worked once after the problem started but now I consistently can't login.

agreed Yes, I but I don't think a metaphysical approach is rigorous enough to go to bat for that particular claim. That's my opinion though, I'm biased because I'm a strict materialist and have been accused before of being a belligerent empiricist. I don't deny those titles. You know me by now Cypress. I'm making my judgment on the premise that their is yet to be even one phenomena that has been attributed to the supernatural. Physical explanations have always arisen to solve our philosophical questions and I believe they always will. Throughout history religion has played "gottcha!" with science every time religion has some "god of the gaps" argument that science cannot yet account for. Geocentric universe, flat Earth, Young Earth, germ theory and the lot. Now days we look back on that and laugh that anyone could have possibly rejected germ theory for demonic possession. Perhaps people like myself and others here will read this post in a few hundred years and laugh that we are even having this debate. That's why I don't like to use the Razor, no one ever agrees on its use. I still think it applies there but I won't fight you over it. Science must assume all questions and all answers are materialistic. Science is the study of materialistic answers. I choose to find my answers in the field of study that brought us space flight, chemotherapy, nuclear weapons, and RNA suppression therapy. There is no other route to truth, other than science, that has repeatably given benefits and results for society. I like metaphysics, but it needs to know its place. It has no place making claims about prehistoric geology. Maybe science will discover God one day, I doubt it, but scientifically I will assume there is no God until sufficient evidence has been brought to light and adequately defended. Metaphysics is great, but it doesn't work in courtrooms, scientific defenses, or calculating the age of the Earth. Yeah there's math too...I think science is the only route to objective truth that me and you can argue about and have a third part come in and declare who is right or wrong. Science is the best route to the truth because science admits that, if one person says 1+1=3 and the other says 1+1=2, somebody is wrong. Science doesn't allow multiple truth values. It keeps things internally consistent and keeps things so objective that sometimes one can feel the chill. ...well you know I can't agree there but we'll leave that in the "Evolution has Never been Observed" thread. Alright, We'll take it down the philosophical road. What's is said deity's motivation for tricking us into thinking the Earth is really billions of years old? Cypress, I'll agree that both sides "don't fight fair" in the sense that I'm fighting from a materialistic worldview while my opponents are fighting from a spiritual worldview. I would rather call it "both sides are playing different ballgames and trying to compare scores". I'm not ashamed to admit though that I think science plays a rougher no-holds-barred ballgame and if the religious want to make converts or gain way with secularists they're going to have to put on their helmets and play the mean and hard hitting peer review game.

Why all the arbitrary restrictions? I'm genuinely curious.

That's just because the energy release associated with those events correlates to that frequency of light because [math] E=\frac{hc}{\lambda} [/math]; where lambda is frequency, E is energy, h is Planck's constant, and c is the speed of light. So for example, the energy of molecular vibrations is of the magnitude to give off radiation in the IR region of the spectrum. Electron orbital transitions are more energetic and usually correspond to the visible/UV part of the spectrum. It all has to do with how energetic the event was that created the radiation. There's really not much difference between a radio wave and a gamma ray. Gamma rays are just way more energetic and therefore have a much shorter wavelength which translates to higher frequency.

Never! Conservation of mass

I think the one advocating the radical counter intuitive interpretation of the evidence is the one responsible for defending it. By this logic I can attack anyone's legitimate physical argument for anything just by suggesting that it might all be an illusion. Not all hypotheses are born equal, claiming that all the evidence is an illusion whether that person accepts the evidence as empirical or not is, to put it mildly, a bold claim an should require bold evidence. If this argument is valid then I should quit school and all these scientists here in the forums should quit there jobs because there is no way of proving that any scientific data gathered isn't just an illusion. I don't like to evoke Occam's razor because it is overused but which explanation do you think fits the evidence and is simpler; the earth being as old as it appears, or the earth happening to appear several billion years old by multiple methods and actually being only a few thousand? I don't see what part of unexplained phenomena pushes one to conclude that some infinite yet still anthropomorphic ghost did it. Science fights fair because it presents all the evidence available in support of or against the claims being made. Religion doesn't fight fair because when it comes to things like age of the Earth and evolution they can never seem to get enough proof or experimental evidence despite the plethora that is available. Then religion refuses to conduct peer reviewed research to support it's counter claim and asks that people just take it on the fact that someone said it. Either the scientific method works and is theoretically applicable in all scenarios or it is total BS and we are wasting our time because there is no way to tell under which circumstances it applies. Someone must provide some testable or predictable, or observable, or repeatable mechanism by which a god could have faked the age of the Earth or that argument will not and should not be accepted by anyone with any objectivity at all. Wild speculation and rigorously analyzed theories that have stood the test of peer review attack are not on equal footing by anyone's measure.

HCl or KHP will work. I like KHP because it is technically better to standardize a strong acid/base against a weak acid/base. One can be more certain that all the KHP has been consumed as all "strong electrolytes" are not equally strong and the precise value of their acid equilibrium constants is not firmly established out in the small decimal places. Plus KHP has two ionizable protons which makes for a more rigorous titration curve if you are planning on plotting a curve. Two endpoints are more analytically sound than just one. NaOH is hygroscopic yes, but so is KHP to a small degree. Just keep your burette covered and be sure to make solutions with a volumetric flasks and not in graduated cylinders. If you haven't done much analytical work before, remember the goal is to be as precise and consistent as possible. The word "anal" is inside the word "analytical".

That's like saying there is a gnome in the refrigerator that turns off the light evertime you close the door. You just can't see him because he only exists when the door is closed. Using your logic, I could defend the "refrigerator gnome hypothesis" against any naysayer. You've set up a totally unfalsifiable conjecture that conviniently always has a way out. All the geological evidence points toward a very old Earth and you're still attempting to marginalize an elephant's worth of evidence by proposing that all the evidence is just an illusion courtesy of the deity who's very existence is the topic of debate. You're assuming you are correct in an attempt to prove you are correct. That's really the worst kind of circular logic, the "premature victory" logic circle. Don't count your chickens before they hatch; and when debating the existence of chickens, don't assume chickens exist in your argument.

-Volumetric titrations are conducted with understanding of the stoichiometry of that particular reaction. Remember that: [math] (moles)=(molarity)(volume)[/math] So if a known volume of a titrant of known concentration is used to titrate a known volume of analyte of unknown concentration. The concentration of analyte can be determined. Endpoints of the titrations are often found with color changing indicators or UV/vis spectroscopy. -Potentiometric titrations are similar, but the endpoint of the titration is found with potentiometry (measuring of potentials in a chemical redox reaction). This only applies to reactions where something is being oxidized and something is being reduced; meaning electrons are being transferred between distinct chemical species in that reaction.

There are molecular propellers: The one pictured here works by attaching aromatic rings to a carbon nanotube in a chiral [non-symmetric] propeller like configuration. The aromatic rings are hydrophobic and repelled by polar water molecules causing the nanotube to rotate. I'm not sure if anyone has derived usable power from something like this used as a turbine, but I know people have observed actual work (work in the strict physics sense) being done on the nanomachines themselves by phenomena like this.

Construct a molecular orbital diagram. [(Bonding orbitals)-(antibonding orbitals)]/2 gives the bond order. Here is an example for [ce] F_2 [/ce]: 3 bonding orbitals (two [math] \sigma [/math] and one [math] \pi [/math]) minus two antibonding orbitals ([math] \sigma^*[/math] and [math] \pi^* [/math]) equals bond order of 1 which makes sense for the singly bonded difluorine. And yes, there can be fractional bond orders like the 0.5 bond order of [ce] Li_2 [/ce].

Yes, but "D-Glucose" is preferred because it is more systematic.

D-Glucose happens to be a "+" compound. So D-Glucose is said to be D(+)Glucose.

Electron orbitals in atoms and molecules are affected by spin-orbit coupling. The electrons' spin can couple to the magnetic field from the nucleus and cause further splitting of orbitals. The coupling is expressed as the sum of all the angular momentum numbers of all the electrons, the sum of all the spin numbers of all the electrons, and the sum of those two sums.

The +/- notation refers to which way the compound rotates plane polarized light, "+" for clockwise and "-" or counter-clockwise. The D/L systems refers to how a compound compares to glyceraldehyde in terms of chirality. The D/L system and +/- systems both refer to the chirality of a compound but there is no correlation between the two.