spin-1/2-nuclei

Hello Finter, Yes, we have differing views, but only in the part that pertains to the specific heat. The specific heat and the kinetic energy are not related. If I may, I'd like to suggest another thought experiment. So, since the temperature is the measure of the kinetic energy. Both the iron and the water are now at 100C, therefore they have the same kinetic energy, but do they have the same internal energy? The specific heat suggests that they cannot. To say this in a more clear way. The temperature of the water and the iron are now the same - so they are both at 100C, thus they have the same average molecular movement. What differs here is how long we had to hold them over the bunsen burner to get to that point. So, if the temperatures are both the same, then we can say that the kinetic energies are the same, but if it takes longer to heat up A than it does to heat up B we can say that A has a different specific heat than B. Thus, First we must mathematically define the object's heat capacity which we will say is.. heat capacity = the heat transfer (Q) / the change in temperature which is just the mathematical way of saying heat capacity describes how fast something heats up. The reason things require different amounts of energy to heat up can be attributed to the molecular and supramolecular structures, because interactions between atoms in molecular systems as well as the interactions between molecules in supramolecular systems will detract from the energy that can be directly used to increase the kinetic energy which must increase to increase the temperature. Let's stop there for now, and check our bearings, and once we are on the same page we can move forward.. Cheers..

Hello, I respect your position, mine is just different, that's all. I'm sorry that my original post in this thread implies that you would be reckless or irresponsible, by default if, you answer this person's questions. I am not trying to personally attack anyone, and rather should have said, that I have my own personal standards on these issues and as they pertain to me, I feel I would be behaving irresponsibly and against my own conscience if I were to provide this person with an answer to their question. I'm a research chemist now, but before I started my PhD I spent some time in the military as a pilot and worked as a volunteer medevac pilot during most of my final years in undergrad and graduate school. From that experience, I have seen a lot of people do some very dangerous things with very basic equipment.. You would be surprised what terrorists can get their hands on off of ebay in terms of lab equipment... and in many cases they get their information from online forums, cookbooks etc, where unsuspecting scientists are simply trying to provide useful general information. So I am more concerned with the poster planning to extract magnesium from something else - because the processes would be very similar - or some other truly dodgy person coming along and deciding that they can apply the information obtained here to their home-grown setup. Lot's of people don't like to obtain receipts for purchasing products/compounds necessary to make their dangerous [enter whatever device/compound here] so they try to find ways to do it themselves at home.. Obviously, this next example doesn't apply in this case, but to further explain the reason why I prefer to be overly cautious, well - it stems from experiences I've had with victims of drug lab accidents, and other such amateur chemistry accidents (amateur fireworks made at home, rockets, tiny bombs for personal amusement, etc). You'd be surprised what bored and mal-informed people do with their scientific "knowledge". The worst part are the burns I've seen on the innocent victims of these homegrown science experiments.. I've transported some unfortunate people to the hospital with various types of burns and other injuries from all manner of accidents.. Thus, I readily admit that I am overly cautious, which is a personal preference, as my personal experiences have changed me.. and what I meant by you are free to do whatever you wish - is simply that you are free to disagree with my interpretation of what is and is not responsible... I did not mean to suggest that you are irresponsible because you do not agree with my definitions. I readily admit that my standards for myself do not have to be - and - nor should they be randomly adopted by everyone else in the world. I am not the evil queen dictator, I just have my own personal preferences, that I chose to adhere to.. To the original poster: Please don't think that I am calling you a terrorist or a drug lab chemist, but you aren't the only person with access to these forums, and unfortunately you did not provide enough information about origin or purpose of your question to set my mind at ease. Cheers..

Hello Finter, The definitions being used here, might be confusing, but the concepts themselves have been widely tested and hold true. Thus the question of what should we call X or Y should be removed from the description of what X or Y does. This is why mathematics is the easiest way to define scientific concepts, in my opinion. It is very difficult to confuse concepts when looking at their mathematical representation. Dr. Rocket, is a maths expert, and I'm sure if you could relay which concepts you're trying to discuss in different terms to him - a mathematical representation rather than a semantic one would follow - and then we would in fact all be on the same page... Please do not take this the wrong way - as I do not mean this an as insult, but rather just an observation that I readily admit might be wrong. However, from perspective, it seems that in Tom's case, he knows what he is doing mathematically and is arguing the use of terms and conclusions drawn in some cases. This is what I would consider a true difference of opinion, whereas, in you case, after reading your post in the speculation thread, I'm not yet sure if you understand the mathematical representation of these concepts and are truly confused as opposed to simply dissenting. So I take back some of what I said in my previous post. If you could clarify that part for me I would better know how to communicate with you from this point on. Cheers

Hello Finter, Internal energy does not change when temperature increases, this is because they are not directly proportional. Temperature is only proportional to the kinetic aspect of the internal energy. This is why we have the concept of specific heat. A though experiment I'd like to propose to you, is to ask yourself why it takes more external energy to heat substance A than substance B. For example, would you say that a 1kg strip of metal would reach 100C faster than a 1kg sample of water? If yes, why? If no, why? Cheers..

Hello Finter, I think it's great to always question the world around you, and to be especially questioning of concepts that - for whatever reason - don't easily sit well with you.. BUT, in order to avoid confusion - especially when discussing well accepted topics like the basic laws of physics - it is necessary to define what your preconceptions are prior to entering the conversation. That way the people attempting to come to your aid will at least realize that you already understand how these basic concepts are stated to work and you merely disagree with those descriptions. Otherwise, those trying to help you get the false impression that you are confused when you are in reality dissenting from the norm (which is okay). I value freewill above pretty much everything else in the universe. It is - I think - the most precious attribute of mankind. All that being said though, If you disagree with work resulting in an increase in kinetic energy then nobody here could have given you any satisfactory definition of heat from your perspective. If you'd stated that from the word go I'd still have been more than happy to discuss the definition of heat from your perspective to see if common ground could be reached, and if not, exchanging different ideas without coming to agreement is not a catastrophe. I will look at what you've written in the speculation thread and restrict any future comments to that thread. best of luck with your studies. Cheers

You can get elemental magnesium from magnesium salts... not to mention the processes for extracting magnesium from things like sea water etc are very similar to other processes, but as I said before you are free to do whatever you wish. I simply do not agree with it.

Hello again Tom, If you're interested in violations of the second law of thermodynamics I have some papers that you might like to review. The first one is from 2002. When I used to TA, I liked to give excerpts from papers like these to try to encourage my students to think outside of the box. Personally, in addition to having a solid understanding of the first principles, I also liked to teach my chemistry and physics students to understand what the data is saying and draw conclusions based on the data and not from any preconceived ideas (even if those preconceptions are based on the first principles). I think it is necessary to teach objectivity along with the basics because many students first starting their graduate work will overlook discoveries simply because their method of thinking about their research is too rigid. Surely apparent contradictions of well established science require careful investigation, but the point is to investigate objectively rather than disprove. Typical disproof will follow, but on rare occasions it does not! Either way, Needless to say, very few students were ever willing to consider a violation of the second law of thermo, but a few did and even correctly deduced apparent violations. As with many things approaching the frontiers of scientific research, there are differing opinions in science about what is and is not a violation of the second law of thermodynamics and whether or not any violations have actually occurred. Since you've already said you don't care about violating the second law, I'm not going to bother to chime in with my own position on that because I think it will take away from the conversation that is finally going somewhere interesting.. at least from my perspective.. Anyway, below are the references. I apologize if you've read some of these already.. 1. Experimental Demonstration of Violations of the Second Law of Thermodynamics for Small Systems and Short Time Scales - "We experimentally demonstrate the fluctuation theorem, which predicts appreciable and measurable violations of the second law of thermodynamics for small systems over short time scales, by following the trajectory of a colloidal particle captured in an optical trap that is translated relative to surrounding water molecules. From each particle trajectory, we calculate the entropy production/consumption over the duration of the trajectory and determine the fraction of second law–defying trajectories. Our results show entropy consumption can occur over colloidal length and time scales." - http://prl.aps.org/abstract/PRL/v89/i5/e050601 2. Probability of second law violations in shearing steady states - "We propose a new definition of natural invariant measure for trajectory segments of finite duration for a many-particle system. On this basis we give an expression for the probability of fluctuations in the shear stress of a fluid in a nonequilibrium steady state far from equilibrium. In particular we obtain a formula for the ratio that, for a finite time, the shear stress reverse sign, violating the second law of thermodynamics. Computer simulations support this formula. © 1993 The American Physical Society" - http://prl.aps.org/abstract/PRL/v71/i15/p2401_1 3. Violation of the second law of thermodynamics in the quantum microworld - "One of the previously reported linear models of open quantum systems (interacting with a single thermal bath but otherwise not aided from outside) endowed with the faculty of spontaneous self-organization challenging standard thermodynamics is reconstructed here. It is then able to produce, in a cyclic manner, a useful (this time mechanical) work at the cost of just thermal energy in the bath whose quanta get properly in-phased. This means perpetuum mobile of the second kind explicitly violating the second law in its Thomson formulation. No approximations can be made responsible for the effect as a special scaling procedure is used that makes the chosen kinetic theory exact. The effect is purely quantum and disappears in the classical limit." - http://www.sciencedirect.com/science/article/pii/S0378437100003459 4. A Quantum Violation of the Second Law? - "An apparent violation of the second law of thermodynamics occurs when an atom coupled to a zero-temperature bath, being necessarily in an excited state, is used to extract work from the bath. Here the fallacy is that it takes work to couple the atom to the bath and this work must exceed that obtained from the atom. For the example of an oscillator coupled to a bath described by the single relaxation time model, the mean oscillator energy and the minimum work required to couple the oscillator to the bath are both calculated explicitly and in closed form. It is shown that the minimum work always exceeds the mean oscillator energy, so there is no violation of the second law." - http://prl.aps.org/abstract/PRL/v96/i2/e020402 hope you find them interesting.. Cheers

Hello, I doubt he'd/she'd be able to extract enough from plants as well, but plants do contain magnesium. It's extremely important for photosynthesis since it is the coordinating ion in chlorophyll. Extraction of chlorophyll is possible, and I assume the calculation of magnesium content per plant is therefore easily possible. edit: yes, I just checked this, as I suspected magnesium does accumulate in chlorophyll and can be extracted from this. Still, I rather assumed he'd/she'd try to get it from seawater or something else once told how to extract it since many of the basic principles would be the same. This would be a very odd homework question in my opinion, and a bench/research chemist at an established university or industrial lab would not bother to extract magnesium from anything since it would be readily available at the chem stores... Thus, since the use of magnesium in incendiary bombs during WWII was quite common, and it's extraction was from sea water was common as well, I avoid telling people how to extract it. It's just my personal preference, you're of course free to provide whatever information you want. Just my two cents.. Cheers

Hello Tom, The comments above reminded me that I forgot to address the ruby and Indiana Jones in my previous post, sorry. I'm quite sick with a head cold and have been working long hours in the lab lately, so I'm a little forgetful at times.. So.... Yes, they do have lasers powered by sunlight. NREL has made one, and a scientist from Tokyo has as well. I found a really good summary article on google, and I will link you to it here. They are making great strides now, the tokyo researcher has found a way to increase the amount of light focused by utilizing small Fresnel lenses in lieu of mirrors.. "The other innovation of Yabe's laser is the use of a small Fresnel lens instead of large mirror lenses. Fresnel lenses reduce the size and amount of material needed to build a lens by breaking it into concentric rings of lenses. Typically, 10 percent of incident light is focused on the crystal, whereas with the Fresnel, it's around 80 percent." - http://www.technologyreview.com/Energy/19402/ and this link to info on the NREL laser: http://www.nrel.gov/news/press/1995/solar.html hopefully this was helpful.. Cheers

Hello Tom, I've been following the laser discussion a little bit, and I think I might be able to help you in some regard. I too think that the semantics surrounding what is a "thermal source", vs. what is "heat" detract from the clear understanding of the topics. Unfortunately science seems content to use the terms interchangeably without regard for the amount of confusion it causes. I think the following might help explain why some physicists call lasers "thermal sources" - i.e. they think lasers - in some conditions - are a different type of thermal source (given that the behavior between the two at that point is indistinguishable) and other physicists point to the differences in the photon statistics and 2nd-order coherence as explanations for their position on lasers - not being thermal sources. In laser physics, The laser and a "thermal source" have different photon statistics despite having the same average number of photons. So both can have the same first order spatial and temporal agreement, bandwith, intensity, and frequency - but in physics they are still considered two different things. So the photon stats are the same for laser light below the threshold of oscillation and a thermal source. So below the threshold the photon counting probability distribution function is utilized and above the threshold the Poisson distribution is utilized to describe the photons. So, in the 1st-order coherence does not discriminate between a "thermal source" and a laser, despite the different photon statistics.. Thus, it is the 2nd-order coherence properties that gives rise to the difference between a laser and a "thermal source". So basically those that think lasers are a "thermal source" are speaking of the lasers below the threshold of oscillation where 1st-order coherence properties apply and those who believe lasers are not a "thermal source" are referring to both the difference in the photon statistics and the 2nd-order coherence properties. I think the Brown and Twiss experiment describes the 2nd-order coherence properties of light. Other key points: Normal optics cannot describe the difference between laser light and light from a thermal source. So it's the statistical fluctuations in the beams of light that describes the difference between laser light and light from a thermal source. So basically the photon counting just describes the quantum nature of light. This is why Swansont is talking about blackbody radiation... This is the common way to measure the differences between the brightness of radiation from a laser and radiation from thermal light sources. It basically describes the degeneracy factor of a photon.. which can often be much greater for a laser than it is for light from a thermal source. So since "thermal sources" can emit light that is temporally/spatially equivalent to that of a laser some scientists refer to lasers as "thermal sources" - in fact many are starting to do this - BUT - because "thermal sources" cannot produce the same "amount" of degenerate photons without the "thermal source" being at temperatures we have not see in the universe so scientists say that lasers are not "thermal sources".. So, the question becomes what is a "thermal source", do we adhere to the old school definition of "thermal source" which came about before we had lasers and make up a new definition for the similarity between the "thermal properties" of the "thermal source" and the laser, observed when using lasers below threshold, or do we modify that definition of "thermal source" to include lasers? So far, from what I can tell - there has been no consensus - as the physicists that we work with refer to lasers as "thermal sources" on a regular basis, as do many chemists, and some do not. For more information on photon statistics, I've provided some sources below.. There is an experiment that was done to describe the photon statistics, and I cannot remember for sure what the name of the Scientist who did the first experiment was, but here are some references that you might find useful. I would also suggest obtaining a book that specifically deals with laser physics and not thermodynamics because the typical undergraduate thermo book will not go into enough detail about the why. A good graduate level book on laser physics will explain the majority of these questions much better - although without reaching definite yes/no positions when viewed from the perspective of each camp, unfortunately. 1. "Phys. Rev. Lett. 15, 943–946 (1965) Photoelectron Statistics Produced by a Laser Operating Below the Threshold of Oscillation" - http://prl.aps.org/abstract/PRL/v15/i25/p943_1 2. This book on laser physics - http://www.amazon.com/Physics-Oxford-Master-Atomic-Optical/dp/0198506929/ref=sr_1_2?s=books&ie=UTF8&qid=1314006397&sr=1-2 I hope this was helpful... Cheers

Hello, Why do you need to extract magnesium from plants? Having magnesium is more than dangerous, it's quite irresponsible to do if you are not properly trained. If you're working at a university/industrial lab and properly trained you can easily get access to magnesium for any reactions you may need to do. I'm sorry but I will not answer this question for you. If you interested in extractions, I will be more than happy to discuss the basic theories behind how extractions work both organic and inorganic, but due to the dangers to you and other innocent bystanders, I won't discuss how to obtain or extract magnesium from anything. If you wander by an irresponsible scientist willing to tell you how to extract magnesium from something please do read the MSDS - http://www.sciencelab.com/msds.php?msdsId=9924535.. Cheers

Hello Finter, Yes there is other energy required to get the containers to this state of having the same temperature but having different pressures. See Boyle's experiment, where holds both mass and temperature constant while changing pressure and volume to prove their relationship. This is called an isothermal process which in most cases cannot occur naturally when compressing a gas. What I was describing was adiabatic heating/cooling - which is the concept that describes the natural - i.e. - un-manipulated behavior between kinetic energy, temperature, pressure, and volume. What I think may have confused you here is a.) many people have chimed in giving opinions of the conditions I presented you with - adiabatic heating/cooling - from the argument of isothermal conditions. Which does not apply to the explanation I gave to your answer. b.) The people that are using isothermal conditions to answer your question are neglecting to tell you that the equilibrium - i.e. holding temperature and mass constant - must be obtained via adding external energy sources or energy sinks whatever the case may be. This is why I said the following earlier: This is why I continued to assume that you were referring to two isolated containers in your original question and were thus trying to ask what happens under normal conditions. When I stated this, you did not come back and state any specific laboratory conditions, and earlier when I stated this: From your responses I felt that using adiabatic heating would be the best way to answer your question. I think adding in laboratory conditions without explaining them only confuses the process and in order to understand that explanation one would have to first understand the relationships clearly given by the adiabatic process. Thus I decided to explain the relationship between pressure, temperature, kinetic energy, and volume with that process. This is because even in an isothermal process the adiabatic relationships apply - they are just artificially held constant via external heating/cooling sources. Without those external sources you will return to the adiabatic systems. Please read this link for more clarity: - http://en.wikipedia.org/wiki/Isothermal_process#Applications "In Isothermal non flow Process, the work done by compressing the perfect gas (Pure Substance) is a negative work, as work is done on the system, as result of compression, the volume will decrease, and temperature will try to increase. To maintain the temperature at constant value (as the process is isothermal) heat energy has to leave the system and enter the environment. The amount of energy entering the environment is equal to the work done (by compressing the perfect gas) because internal energy does not change. The thermodynamic sign convention is that heat entering the environment is also negative. Thence Q = W. In equation of work, the term nRT can be replaced by PV of any state. The product of pressure and volume is in fact, 'Moving Boundary Work'; the systems boundaries are compressed. For Expansion the same theory is applied." Thus, because I described my conditions as adiabatic heating, and some people who did not read the thread in it's entirety and just chimed in after Swansont quoted me answering your question - they did not understand that they were arguing against the validity of adiabatic heating/cooling... which most accurately describes what will happen to a system when it is absent of laboratory/external heating/cooling sources. That is to say. Always - whenever you change the volume you will change the pressure, which will change the temperature. This change in temperature can either have an impact on the kinetic energy or can be held constant artificially via adding/removing the energy from the system in the form of heat transfer via an external heating/cooling source. This is the explanation that I think has been missing from the descriptions of the isothermal process. The why - of how the temperature remains constant - isn't that the temperature is not rising as a result of the change in pressure, but rather it is because the rise in kinetic energy which leads to the rise in temperature is kept at equilibrium (i.e. the temp and mass are kept constant) artificially via external means. Hope this helps.. Cheers

Hello, I'm sorry to hear about what has happened to you. I would suggest getting in to a community college that has a transfer agreement with a major university that you'd like to attend. You can drop out of high school and go directly to a GED, and that would get rid of your HS GPA for sure. This is something you'd want to do with the advice of a good guidance counsler. From my perspective, if you get a GED, then study up and ace the SATs you can then go to a decent community college or maybe even get directly into a 4 year school if they will take your GED/SAT in lieu of your HS transcripts and let you in. If you have to go to community college and you want to be a doctor here is what I suggest. Take all of the calculus I-III, Engineering physics I-II, general chemistry I-II, labs, organic chemistry I-II with lab (if you can get that at the community college), biology I-II with labs, Anatomy and physiology I-II. Then when you get to University so long as you major in a science and mind your GPA in both community college and University you should be fine. Med schools care a lot about having done undergraduate research, so make sure you do research with at least two different labs. Major in Biochemistry, Biology, or Chemistry instead of premed, and try to get in some extra curricular activities and/or volunteer work. Letters of recommendation mean a lot and so do interviews. You're life isn't over until it's over, and if you aim high and fall short of your dreams then you can still pick up the pieces and have a good life if you've aimed high enough. I wanted to be an astronaut. During undergrad, I worked as a private jet pilot and a helicopter pilot for my dad's company. I really thought I had a chance because I started college really early and got multiple degrees in chemistry/physics/ and engineering. Then I got injured on my motorcycle and I knew I would never stand a chance of being an astronaut.... I am a research chemist now. I never got a chance to even try to be an astronaut, and I almost lost my 1st class medical and my civilian ATP 2 years after I got it. I worked on getting out of HS early and becoming a pilot at 16. Had this planned from when I was a little kid, and then life happened. So, even if you do everything right you can get a curve ball.. In your case, you're still young and you know your grades are not a sign of your ability or your intelligence when you're in a bad situation. Just do your best and don't let anybody else tell you that you can't be a doctor if that is what you want to be. It might be harder for you, but harder doesn't mean impossible. If you do find that you're a little behind because of your environment - then take classes slower - go part time - and if you can get a tutor. Even if you are not struggling - it might be easier to get a tutor if you don't have the same amount of free quiet time to study as other kids in normal environments. Best of luck, and keep your head up. All you can do is your best, and I am not convinced that you can't be a doctor just because of your HS grades. Cheers.

I disagree, I didn't say that it could never warm up to room temp, what I said is that it does not warm up to room temp in or lab (that would result in a nasty lab accident). From the rest of my post, it is clear that I attributed outgassing to the cooling of the argon system, and that I was saying liquid nitrogen is able to remain cold in the cylinder despite the cylinder being exposed to ambient temperature. Just like for some reason Swansont thinks I should adopt his reasoning for how to answer a question, some people here seem to think that context is not important. Swansont is of course free to disagree with my interpretation of how the person expected the question to be answered, but he cannot disagree with the concept of adiabatic heating/cooling without providing references. As I said before, in the context of the thread - "What is heat?" - answering the question with the concept of adiabatic heating/cooling makes more sense to me because it more clearly explains the relationship between "heat", kinetic energy, pressure, and temperature. Can I boil water at room temperature, sure? But in the thread "At what temperature does water boil?" The most appropriate answer is 100C. They aren't asking at what temperature can I get water to boil if I'm using a vacuum pump. You're not taking two identical containers of gas and compressing one of them without a change in temperature and pressure unless you are in the lab. In the real world if I cap two soda bottles and squeeze/compress one of the - the one getting squeezed and compressed is changing temp, pressure, and volume. Cheers @Swansont, Sorry I did not see your reply before I posted the last comment. If you're saying you agree with adiabatic heating but not my decision to use it to answer finter's question then I apologize that I've obviously misunderstood your position. This was not clear to me earlier. Regarding the use of lasers as a thermal heat source - I agree that the term is ambiguous but either we need a new definition of heat source or we need a new term to describe the "other energy" that results when people use lasers in chemistry and other fields. This is why I asked for a reference on this. I do a lot of work with chemical physics in my research and the physicist whose laser lab we often use in our research refers to lasers -under certain circumstances - as a "thermal source" as well. At this point I'm hoping for a discussion not a debate. So, I'm not asking for a reference to insult your intelligence, but rather to obtain more information. Lately, many scientist - some of them physicists are now starting to refer to lasers as thermal sources. This is either because the definition of thermal source is changing in physics as well, or because they are incorrectly using the term.

@swansont Oh so now your two containers have external heat/cooling sources? If thats not moving the goal post what is? When did the original question say we could arbitrarily arrive at the conditions however we wanted to. Moreover, I'm not the one getting the basic physics wrong. So yes when you claim two different sized bottles filled with identical amounts of gas have the same temperature and different pressures you need a reference for how you're pulling that off under the constraints of the question. If you're claiming the question can be answered however we want then I say adiabatic heating/cooling makes more sense, since the poster never define conditions for an experiment. The ambiguous part of this discussion is your ever changing undefined experimental conditions. Surely the responsible approach to answering this question - when there were no experimental conditions given in the question - is to define the ones you're using. I defined mine as adiabatic conditions wherein the work done on the container to compress the gas is transferred into kinetic energy which in turn increases the temperature and the pressure while decreasing the volume. You've consistently disagreed with this being possible, and moreover it is the experiment most in line with the conditions given in the question. So yes, if you're going to disagree with commonly held principles such as adiabatic heating and cooling you need references. If you're going to disagree with the common use of lasers as a heating source and even other scientists who state that lasers can be used as a thermal source under certain conditions then you have to provide sources for that too... @cap, Please tell me how you can heat something up to room temperature that is hotter than room temperature? Perhaps you should be more clear...

@swansont, "explain to me how this is not possible" What for? As Tom says clearly many people here like to draw circle. The answer to your questions and challenges are in the many examples provided to you as well as the many linked scientific papers and I believe Tom linked you to an experiment that should help clear this up for you. Shrugs, There really is nothing more that can be said. Best of luck with whatever you do professionally but this forum is not for scientists. Even in situations where what's happening in reality is ambiquous, discussions in my lab, at conferences, and seminars do not degenerate into circular nonsense. The reason for this being, at least where I am from, is people are willing to back their claims up with references and they avoid moving goal lines. I guess this is because in research the discussions are about the advancement of science and not about being right.

You said the temperature would be equal - which it cannot as the pressures are different. An increase in pressure results in an increase in temperature. Things will eventually equilibrate in an unsealed container via outgassing - and thus the amount of gas molecules in one container are no longer the same as the amount of gas molecules in the other container. You cannot warm a gas without expansion, you cannot expand a gas in a container without increase the pressure. If it is sealed - i.e. - heating a closed system - you get an increase in pressure as a result of the increase in temp - which in unfortunate cases can result in explosion or structural failure. This is why you have no idea what you are talking about. It is not possible to increase the pressure without increasing the temperature when only one parameter is changed. In this case container size. This makes no sense. You are the one adding extra parameters to the situation in order to try to make the impossible possible. It doesn't matter how you get those two containers to have the same amount of gas - getting them at the same temperature requires getting them at the same pressure - see how compression works - and equilibrating them to ambient temperature requires a change in more than parameter of the system, for example outgassing to reduce pressure in the smaller container - i.e. changing the amounts so that they are no longer fixed. Semantics is not a substitute for valid science. What fixed volume - for a gas - can be had in different container sizes? Gasses expand to reach maximum entropy (i.e. they get as far a part from each individual gas molecules as allowed by the system) - unlike liquids - due to their increased kinetic energy relative to things in the solid and liquid state which only exert pressure on the part of the container they are touching - whereas gasses exert pressure on all points of the container in all directions. If you were to take a logic class - you will discover that simply saying something does not make it true. A laser can be a thermal source. This is the problem with trying to discuss advanced topics at an undergraduate level of understanding. Most people figure out during the PhD that there are plenty of exceptions and modern expansions on top of the basics. Observe: "We present a unique bubble generation technique in microfluidic chips using continuous-wave laser-induced heat and demonstrate its application by creating micro-valves and micro-pumps." - http://pubs.rsc.org/en/Content/ArticleLanding/2011/LC/c0lc00520g OMG! Swansont these people did not get the memo about lasers not being a heat source, neither did the people below. And did you know many universities have laser thermal labs? For shame! They should be closed down for fraud! All of their data must be faked. Miserable creatures, if they were really experts in physics they should know that lasers are not a source of "heat", because they are not a "thermal source", right? Maybe you should take some time to school them on the way "reality" works. "THERMAL LASER EXCITATION BY MIXING IN A HIGHLY CONVECTIVE FLOW" - http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4842113 "In this section the laser will be considered as a thermal source and not as a primary source of highly monochromatic coherent radiation." - http://docs.google.com/viewer?a=v&q=cache:baCcDQu9jMMJ:old.iupac.org/publications/analytical_compendium/Cha10sec316.pdf+lasers+are+not+thermal+sources&hl=en&gl=za&pid=bl&srcid=ADGEESjv1iBgUqWvJFW-txJ5NvfAmSDUbVcy1vUW85gh0epW4IKZY5Cct0EnnaCV8xkakSyjcre-At9iYvsEbcbfCDq0m3nr6vfSaDjVSGr-NtouJQMRQNDmQJbfwGTsI_AYrpNEtd5Z&sig=AHIEtbQhe34LapLo4hq2bkRnKIZPx9vC_A LOL! sigh..

Holy crap?! Seriously?! I NEVER said liquid nitrogen tanks don't warm up to ambient temperature, what I said was they don't do this by themselves in the absence of some sort of equilibrium. That was implied by what I said when I said that you can't keep the temperature the same in any two systems with the same amount of gas while changing only one other parameter (please see the example I gave with the soda bottle). I incorrectly assumed that people here - since they are claiming to be experts - would have been familiar with a liquid nitrogen tank. Clearly I was wrong. Two things you need to know about a liquid nitrogen dewar. 1. they have vacuum systems. Why? 2. They have a pressure release valve. Why? Thus, as I have been saying and saying - you need to have outgassing in the system to warm up a compressed gas to room temperature without a catastrophic failure or explosion. If you do not do that, as I said before with the example of a soda bottle being squeezed - you will get either an explosion or a structural failure. Do you people realize that gasses expand when they warm? This, combined with other factors, are the reasons for why you cannot just change one parameter (volume by shrinking container size) and keep all the other parameters the same. Therefore, Swansont is just wrong. You cannot have two samples of gas at a fixed amount in two different containers with the same temperature and pressure and volume. For starters the volume changes by virtue of changing the container. Moreover, if the temperature is different then the pressure will be different, all day every day. Swansont is incorrect - what he is suggesting is impossible no matter how you slice it. Those gases at fixed amounts in different size containers cannot have the same temp. It is also impossible, despite what some here have suggested - to warm a compressed gas to ambient temperature without a change in pressure. If you are intent on increasing the temperature without increasing the container size, then you will need to utilize outgassing - to lower the amount of gas molecules inside the container - unless the desired result is an explosion or structural failure. As I have been saying and saying.. Observe people, "Since the liquid to gas expansion ratio of nitrogen is 1:694 at 20C, a tremendous amount of force can be generated if liquid nitrogen is rapidly vaporized. In an incident in 2006 at Texas A&M University, the pressure-relief devices of a tank of liquid nitrogen were malfunctioning and later sealed. As a result of the subsequent pressure buildup, the tank failed catastrophically and exploded. The force of the explosion was sufficient to propel the tank through the ceiling immediately above it.[6]" - http://en.wikipedia.org/wiki/Liquid_nitrogen Pray tell - how does the pressure release valve on a liquid nitrogen tank work people? Please describe it without correlating it to outgassing (i.e. the release of gas from the system to lower the pressure).. sigh.... I am in awe.. I don't even know what to say.

If the gas is in a pre-compressed bottle the only way it will cool down to room temperature is if there is outgassing - thus changing the size of the sample. People here are confusing the concept quantifying a fixed sample size across many different systems where the only thing changing is the size of the container - in which case by virtue of the situation their temperatures cannot be the same for all the reasons I've mentioned before. and the concept of Many different sized containers of different amounts of gas can be at the same temperature or a container that was at one temperature can cool down or heat up to another temperature if there is outgassing or if there is an external heat source. For example, the cylinder of liquid nitrogen used for the laser in my lab remains the same really cold temperature while compressed inside the cylinder. That is to say it does not equilibrate and warm up to room temperature. That would be unfortunate for us. Another example, is my argon tank, which loses gas - sent to my reactions via the Schelenk line - whenever I'm doing reaction and as a result it's temperature decreases because the volume increases as does the pressure as gas is let out of the system. The decrease in temp is the result of the decrease in kinetic energy - and the decrease in temp leads to a decrease in pressure. Spray a can of something compressed and fill it get cooler to prove this to yourself. I'm sorry, but I really don't know what else can be said on this issue to clear this up. I've tried my best, but at some point bridges can't be built. I really hope this helps, but if it doesn't I don't think there is anything else I can say. Cheers

@swansont What you're saying is still incorrect. Its alarming that you think equal amounts of a gas in different size containers can be placed in any sized container & experience no changes between them. For every action there is an equal and opposite reaction. It doesn't matter when or how the gas is placed into a smaller environment, work must be done to compress gas. Though I suspect you may not know this, you are suggesting that any amount of gas can be compressed into any size container and no matter what container we check those gasses will always have the same temp. Its obvious that what you're saying is wrong when you consider: The fixed amount of gas cannot teleport itself into the smaller container, nor change the laws of physics to scale itself down accordingly. I give up trying to reason with you. This is absolutely ridiculous.

Hello, What you're describing is impossible. You cannot keep the energy the same while changing one parameter and keeping the other's constant. This is because work must be done on the system to force the gas into the smaller container size. That decreases the volume of the gas, when that happens work must be done. The work is then converted to kinetic energy - which results in the increase in kinetic energy/thermal energy temperature and the increase in pressure. To prove this to yourself, try the capped plastic bottle idea I suggest above. Cap a 2liter plastic soda bottle tightly - an empty one - and then squeeze it as hard as you can with vice grips. You will see that when the container size decreases - i.e. - when you compress the gas - via the work applied to the system work will be done, which will then be converted to kinetic energy. Once that happens the temperature will increase. Once the temperature increase the pressure will increase. If you continue squeezing you will eventually see that the bottle will explode or it will have a structural failure from the increase in pressure. If you take another 2 liter bottle and cap it and leave it on the counter whilst you squeeze the other bottle (i.e. make it smaller with the same amount of gas molecules in it as the unsqueezed 2 liter bottle) you will see that what you are suggesting is impossible.. So no external energy (i.e. heat source or light) is added to the system but changing the size of the container does work in the system. Which is converted to energy kinetic energy. hope this helps.. Cheers

I disagree, you've misunderstood the concept adiabatic compression as well as the ideal gas law. If you change the container size, you will change the volume. This change in volume will result in the change of pressure. Therefore you are incorrect, the two samples cannot have the same temperature because they cannot have the same kinetic energy. You must use the concept of adiabatic compression because you have no external heat/energy source to account for the change. Thus, in the case of the smaller container, it is the work done on the system by the decrease in volume that results in the increase in energy, which is converted to kinetic energy, which in turn raises the temperature of the system as well as the pressure. Even if you assume that the container expands to some degree - the containers are of identical composition - and are not the same size - thus your reasoning still falls apart. Container expansion would only impact how much of a change not if there was a change at all. To prove this to yourself, go take a tightly capped plastic bottle filled with air, get a vice grip from your garage and see if you can squeeze it until it pops off it's top or cracks in some other location. Then ask yourself, why did this happen? If you were to quantify the condition of the air molecules inside your bottle you'd see that you've not only increased the pressure by mechanically compressing the bottle with your hand, but you've also raised the temperature and as a result the kinetic/thermal energy, in addition to increasing the pressure - to the point of explosion/structural failure actually. This is because if you compress the tightly capped bottle hard enough with the vice grips, an explosion or structural failure is exactly what you're going to get. "Adiabatic heating occurs when the pressure of a gas is increased from work done on it by its surroundings, e.g. a piston. Diesel engines rely on adiabatic heating during their compression stroke to elevate the temperature sufficiently to ignite the fuel." - http://en.wikipedia.org/wiki/Adiabatic_process#Adiabatic_heating_and_cooling Thus when all other things are created equal - the size of the container matters a lot. Hope this helps.. Cheers Hello, No, there is no extra energy put into the system. The work comes from the force applied when changing the container size. This is how adiabatic compression works. The only way you can change the temperature of a system is to change it's kinetic/thermal energy. A system can absorb energy and use it for many things, but if the temperature of the system increases then there must have been an increase in the kinetic/thermal energy. Now, there are situations when equilibrium can result in no observed change in energy, but that is not the case here. In the example you gave everything was fixed but the size of the container. Hopefully this was helpful. Cheers

This is incorrect. Temperature is directly proportional to kinetic energy/thermal energy and temperature is related to volume. See Charles' Law & adiabatic compression. In this case, they cannot have the same temperature, because their volumes will not be the same. Since they cannot have the same temperature, they will not have the same kinetic energy. What you're suggesting in your answer is that volume has no relationship to temperature or pressure in PV=nRT. In this example the smaller container will have the smaller volume. So, the work done to compress the gas into the smaller container (because the number of gas molecules in the large container is identical to the number of gas molecules in the small container) will be transfered to the system and converted into kinetic energy, which will in turn increase the temperature. An increase in temperature results in an increase in pressure. hope this helps.. Cheers

Hello, Yes, that is correct, but it is an oversimplification to say that the electronic configuration of atoms gives rise to the macroscale properties observed such as "wetness", or elasticity, or rigidity. Moreover, all macrosystems in the universe are almost infinitely composed of microsystems, and within these systems there is a constant struggle between external perturbations of "isolated" ares and the internal struggle of the "isolate" system to reach it's thermal equilibrium. That is to say that all systems strive to reach their lowest energy, but in reality this typically turns out to be a situation where some parts of the system are at higher energy than other parts, and when those higher energy/reactive parts of the system happen across other low energy parts of a different or within the same system that were previously isolated from the aforementioned higher energy parts, interaction to achieve the lowest possible energy between those two subsystems or macrosystem and macrosystem occur. Objects in the macroscale, such as tennis balls or cubes of ice, are made up of systems of molecules, which are made up off systems of atoms, which are made up of systems of subatomic parts. The entire system is the sum of all it's parts. If you want to look at the properties of a supramolecular structure, the best way to do that is to look at the systems of molecules that make it up. Sure all of those molecules have atoms, which in turn have their own subatomic systems, as I said before - but knowing that a supramolecular structure is composed of hydrogen, oxygen, carbon, sulfur, and nitrogen atoms does not tell us anything about how that suparmolecular structure will look or even behave. Even knowing that supramolecular structure is composed of certain molecules like for example the amino acids is not going to tell us much about how that supramolecular structure will look or behave. (see the protein folding problem and enzyme activity) For any given protein sequence - you cannot from that infer what the structure or reactivity of the protein is - what makes the protein the protein on the macroscale (i.e. the scale most relevant to us) is the sum of all it's parts, the atoms that make up the molecules that make up the sequence, which has a specific connectivity, which gives rise to the geometry, which gives rise to the structure, which gives rise the function. Another way to look at this is to simply say - not all hydrogen atoms in a molecule or a system are the same. On both the molecular and supramolecular level the environment that the hydrogen is in will have a huge impact on what that hydrogen does. For example CH4 has four hydrogens that in most cases aren't going to be very reactive. On the other hand H3C-(C=0)-OH has four hydrogens as well, but because of the environment of those hydrogens 1 of them (the carboxyllic acid hydrogen) is going to be relatively reactive. In yet another example, we have H3C-CH2-OH, in this case the hydrogen of the alcohol is going to be the most reactive relative to the other H atoms in ethanol. But if you compare the three, by an acidity measurement called pka, you will see that despite being comprised of mostly the same atoms (hydrogen, oxygen, carbon) these systems of atoms - i.e. molecules - are not the same. Methane is the least reactive, followed by ethanol, and then acetic acid. Methane has a pka of 50 Alcohol has a pka of 16 Acetic Acid has a pka of 5 So even though every hydrogen in the example above has the same electronic configuration, the reactivity of the hydrogen atom in each situation is not the same. The same can be said for the carbon, and oxygen. So for example, carbon's electronic ground state configuration is [He]2s^2 2p^2 - meaning that carbon's valence electrons allow for carbon to have 4 bonds. When you calculate the formal charge of an atom in a molecule: FC = [Valence electrons] - [# of lone pair electrons] -[# of bonds]. For carbon you will see that in all the examples above this is 4 - 0 - 4 = 0 therefore the carbon is neutral in those molecules. Now, if we consider a carbon atom during an SN1 reaction, where the carbon of the reaction center - having just lost a bond via the loss of a leaving group - we can see that in this case the carbon has a formal charge of +1 R3-C+, where R stands for other systems of atoms covalently bound to the carbon. You have: FC = 4 - 0 - 3 = +1 So now that we know that atoms within molecular systems can have charge, it is important to note that it is the environment those atoms are in that determines whether or not the atom can hold the charge that is being proposed. the more electronegative atom "prefers" to have the negative charge, the less electronegative atom "prefers" to have the positive charge, but this is only if charge separation cannot be avoided. A good way to understand this is to take a look at what we call resonance structures. if I have H2C=CH-HC=CH-CH=CH2, from right to left carbon(s) 1 - 6 In a resonance structure we can move sources of electron density, but we cannot make or break bonds (there are many other rules as well, but they are not overly relevant to the large picture here so I will skip those for now) So step 1, I move electron density from carbons 1 and 2 to carbons 2 and 3, and (so that I do not violate the octet rule) I also have to move electron density from carbon 2 and 3 to 4 and 5 and the final double bond to carbon 6 in the form of a lone pair/negative charge. This leaves a positive charge on carbon 1, which is a primary center. A primary center, simply means that the carbon has only 1 out of the 4 bonds possible being a non-hydrogen bond, and a negative charge on carbon 6. It's important to note that moving double and triple bonds is consider moving electron density, but once you get down to the final single bond between two atoms - you cannot move that bond - when you are drawing resonance structures. Now we have: H2C=CH-HC=CH-CH=CH2 <--------> H2C(+)-CH=CH-CH=CH-CH2(-) So now we understand that within a molecular system, depending on the environment/conditions, different atoms can have different charges. This leads to different reactivity of the same atom. *it's important to note that the overal energy in the system will not change. That is to say conservation of energy must be obeyed, and that is why if you add of the charges on both sides of the arrows above you will see that there was no net loss or gain on the energy of the system, but there was a significant change in the energy of each of the charged carbon atoms. So while the net energy of the system is not changed the stability of the system is changed. In real life all molecules exist as an average of all of their possible resonance structures, those that are neutral - i.e. - more stable are weighted more because the molecules spend more time in the more stable configurations. This is just scratching the surface of how atoms behave within molecular systems. I don't have time or space to go in to them all, but hopefully this gives you a pretty good idea of the complexity involved in these concepts. Systems of molecules have similar behaviors. Even though most supramolecular biological compounds are made up of systems of amino acids, the arrangement of those amino acids greatly determines the structure. inherent chirality, hydrogen bonds, pi stacking, hydrophobic/hydrophillic interactions, blocking/encouraging rotations and vibrations of pockets of molecules in the supramolecular system, sterics, etc, etc all determine the structure and function of those proteins and they function in a way similar to what has been described for atoms in their molecular systems. The amount of contribution made from one or the other depends greatly on the environment. Molecules in their supramolecular systems will align themselves in such a way that electron density is shared for the benefit of the entire system, as much as can be achieved. Because as I said before, all systems are looking to achieve the lowest energy possible, i.e. they all want to become the most stable. This post was not all inclusive by any means, but it should give you a good understanding of the very basic aspects of this so that you can now know where to start to research this further, if you so desire.. Hopefully this was helpful. Cheers

You've misunderstood what I said. Yes I disagree with you, but it's not because I think temperature = heat or because I don't believe physics defines "heat" as Q, but rather because your position is very confused. In some cases your definitions for your terms are correct, but because your application of those definitions to the real world are flawed it is not possible to have a productive conversation. Many times you're overlooking the quantum mechanical applications of these principles, and advancements made by modern science. All of my colleagues are aware of this. That is why when other people define their terms either during the body of the text or beforehand, people typically move on to understanding the content of the research in lieu of arguing about which definition of what term should have been used. A mathematical proof remains sound no matter what letter or symbol one decides to use to define the different parameters. For example: "There is some debate in the scientific community regarding exactly how the term heat should be used.[5] In current scientific usage, the language surrounding the term can be conflicting and even misleading. One study showed that several popular textbooks used language that implied several meanings of the term, that heat is the process of transferring energy, that it is the transferred energy, i.e., as if it were a substance, and that is an entity contained within a system, among other similar descriptions. The study determined it was not uncommon for a combination of these representations to appear within the same text.[6] They found the predominant use among physicists to be that if it were a substance." - http://en.wikipedia.org/wiki/Heat#Semantic_misconceptions When talking about energy that has been or is being transfered my colleagues and I use "heat" and thermal energy interchangeably. When talking about energy that is contained within the system we refer to it as either kinetic energy or thermal energy. This is because from our perspective energy is never created or destroyed, thus it doesn't really matter what we call it so long as we appropriately quantify it in our system. By doing things this way, progress in research can be made. Otherwise we'd spend all of our time writing essays on the semantics of the definition of heat. That is why, as you can see from the reference I've provided above, most scientist are more concerned with their research than they are with the semantics. You need a term to define the energy measured/described by the temperature and transferred between objects and systems. You've yet to provide an alternative to heat that would be functional in a research environment. ======================================== I especially take issue with your interpretation of heat and temperature. "Sensible heat had a clear meaning in the writings of the early scientists who provided the foundation of thermodynamics. James Prescott Joule characterized it in 1847 as an energy that was indicated by the thermometer." - http://en.wikipedia.org/wiki/Sensible_heat The above definition of "heat" corresponds exactly with mine. On the other points: I'm sorry but your interpretation of these concepts is wrong. I've already gone over why in previous posts. So, I will just address your points with quotes from scientific journal articles at this point. Your statement: "Heat" cannot be stored/held & systems do not have heat. " - I'm sorry but, this is just wrong: "As an alternative to storage of sensible heat in liquids or solids or as latent heat of fusion, heat storage by means of reversible chemical reactions is under investigation. By this method, a chemical is separated into two components by heating and heat absorption, following which the components are stored in separate vessels and are recombined to generate heat when it is needed. The attractiveness of this concept of heat storage is not only higher energy density, but the capability to store energy as long as desired at ambient temperature, the option of transporting the chemicals to generate heat at another location, and the high temperatures characteristic of some of the reactions which result in high efficiency when the stored heat is used to generate electricity." - http://www.sciencedirect.com/science/article/pii/0022459677901888 Sensible heat - is the energy exchanged by a thermodynamic system that has as its sole effect a change of temperature. (this definition came about as a direct result of semantics no doubt.) - http://en.wikipedia.org/wiki/Sensible_heat More from the same source: "The terms sensible heat and latent heat are not special forms of energy, instead they characterize the same form of energy, heat, in terms of their effect on a material or a thermodynamic system. Heat is thermal energy in the process of transfer between a system and its surroundings or between two systems with a different temperature." Another source: "This paper presents the results of a comparative numerical investigation on packed bed thermal models suitable for sensible and latent heat thermal storage systems." - http://www.sciencedirect.com/science/article/pii/S1359431198000817 ====================== 2. In regards to your comments about temperature, the sources below contradict your statements: - http://en.wikipedia.org/wiki/Temperature#Heat_capacity "Temperature may be viewed as a measure of a quality of heat, as distinct from a quantity of heat.[1][2][3][4] The quality is called hotness by some writers." "In the context of thermodynamics, the kinetic energy is also referred to as thermal energy. The thermal energy may be partitioned into independent components attributed to the degrees of freedom of the particles or to the modes of oscillators in a thermodynamic system. In general, the number of these degrees of freedom that are available for the equipartitioning of energy depend on the temperature, i.e. the energy region of the interactions under consideration." "On the molecular level, temperature is the result of the motion of the particles that constitute the material. Moving particles carry kinetic energy. Temperature increases as this motion and the kinetic energy increase." =======================