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but important

but important

Just being a stickler here' date=' but i would like to point out that one does NOT get energy by breaking the ATP phosphate bond. In fact, one can [b']never[/b] get energy from breaking a bond. Breaking bonds always requires energy. The way that we get energy out of the reaction is that ATP --> ADP + P and then the ADP and P go to form other products (lets call them products "B") wich are lower in energy that the original ATP. It is this ("B" being lower in energy than ATP) that causes the body to be able to obtain free energy. Well...it is kinda a nit-picky sort of point, but i think it is still important. I don't know how many people (chemists) that i have talk to that belive that breaking the ATP bond actually produces energy. The problem is that we often gloss over the second step and just say that it produces energy. But i think it is important to have a correct conceptual grasp of the mechanisms of chemistry. IN this case, bonds form because they are a lower energy state than the seperate reactants. So energy is given off. Nessesarily, energy must be absorbed, then, when the bond is broken. That is all Yay!

Just being a stickler here' date=' but i would like to point out that one does NOT get energy by breaking the ATP phosphate bond. In fact, one can [b']never[/b] get energy from breaking a bond. Breaking bonds always requires energy. The way that we get energy out of the reaction is that ATP --> ADP + P and then the ADP and P go to form other products (lets call them products "B") wich are lower in energy that the original ATP. It is this ("B" being lower in energy than ATP) that causes the body to be able to obtain free energy. Well...it is kinda a nit-picky sort of point, but i think it is still important. I don't know how many people (chemists) that i have talk to that belive that breaking the ATP bond actually produces energy. The problem is that we often gloss over the second step and just say that it produces energy. But i think it is important to have a correct conceptual grasp of the mechanisms of chemistry. IN this case, bonds form because they are a lower energy state than the seperate reactants. So energy is given off. Nessesarily, energy must be absorbed, then, when the bond is broken. That is all Yay!

hey mark10, as per your questions, i would say the following... 1) What you say makes sense. If you are going to have to use only the cis-trans convention, then assigning E and Z and then correlating them to cis-tras would work. However, this obviously defetes the whole purpose of the E-Z notation. But if you teacher wants only cis and trans then i guess that is what you have to do 2) Well...is there really a right and a wrong in styles of teaching? Personally, i would see no problem in teaching both cis and trans and E-Z at the same time. But others might feel this would be confusing and so would teach only the cis-trans the first time around. As far as what you are expected to know, i think that only your teacher would know that. I would go an see him/her and let her know that you understand the E-Z stuff and would like to know how they would like to see things reported. Anyways, way to figure this stuff out! it is good to see someone actually follow a link and read up on their own. I think you learn stuff much better that way, then when you just get posted answers to questions. Cool.

i would imagine that you wouldn't need the activity to check your answer. If you knew the half-life of U-238 (i suspect that is easy to find) then you can see if your answer makes sense. Ie. would 9000 dis./sec over the half-life of U-238 amount to half of the U-238 in a 1 gram sample being disentigrated. I think this would work? Who knows though, i never really took nuclear physics and all that.

for questions concering naming of substances, you should prolly consult the IUPAC website http://www.chem.qmw.ac.uk/iupac/ It is IUPACs mission to give "Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc" if you are still confused after reading this, then post again, and i will see what i can do to help you out

no. But of course, it never has an exact position. One of the uncertanty priciples states that we cannot ever know the position and momentum of an object to an arbitrary degree of certainty at the same time. Which would make it seem like we could determine position exactly, however, we know that the moon cannot be moving faster than the speed of light, so we have an upper bound for momentum and hence, a lower bound for how precise we can know the earth's position.

just because a particle is not observed does not mean that it doesn't exist. Indeed, if particles came into existence just when they were obseved then there would have to be a whole lot more energy floating around than there is. All that it means is that a particle exists in a superposision of its quantum states until it is obseved, at which time the particle colapses into a single state. So, things do not rely on observation for their existance -- but they do rely on observation to bring them into a single, definate, state. Of course the consiquences of this also somewhat reast on what you consider "observation" to be. And people have been arguing about this for quite a while now.

hmm...it seems in retropsect that my use of the word "grow" was a poor one. I meant to use "grow" in the sense that the neurons are growing together to form connections with eachother. To my knowledge (admitedly incomplete) brain cells cannot be cultured in the normal way in wich we think of that. That is, you cannot take some cells from someones brain, put them into media and have them multiply. Of course i could be wrong about this. Whether or not it is possible for us to cause brain cells to multiply or not, this is not what was done in the article. What was done was mouse brain cells were placed on a plate in media and they were allowed to "grow" such that they re-established connections with eachother. Thus this group of cells formed a sort of minuature "brain." But this was all in the links i posted. From the article in my first link, paragraph 8

What does??? I thought all the cool math people just got done explaining that 0*inifinity is a meaninless concept' date=' the operation is not defined, and has no real value in math? how does this suggest that 0 is stronger than infininty? But the question is does 0/0=1? Which i don't know, buti suspect that the answer to this operation is undefined so i don't think it would really matter. But even if 0/0=1 why would this change anything? 2*8=16 does the fact that 2/2 =1 change anything intrinsic about the number 2?

arg...i realized that i mis-spoke (mis-typed?) yesterday and i would like to correct my self I had said; Which i belive is acutally a bunch of rubbish What i meant to say though was this; Adding heat to a system usually increases the temperature, though there are some systems for which this is not true. For example, gravitationally held systems (like our galaxy) have a negative heat capacity and as such adding heat will cause the temperature to decrease. That is all i wanted to say.

first off great question! well, it doesn't really defy entropy, but it might be hard to see where the entropy might be going too. It is clear that the iron fillings are being ordered, but what you also must take into acount is that in order for the iron filings to be ordered, there must be a force applied and the iron fillings must be moved. This will require some energy. We can imagine that some of this energy will be lost to the surrounding area (friction with the surface as they are dragged about. ect) as heat and thus will increase the entropy of the surroundings. So there is at least one way that we can see entropy might be increased. There might be more, i am not sure. I don't really have time right now to think about this exhaustivily, though someone else here might. As a more simplistic example consider the task of you cleaning your room (or a child stacking biulding blocks). Clearly the entropy of the room appears to decrease, as things are put away. But what you might fail to notice is that your body is doing work on these objects and in order to perform this work it must make energy. Durring the proccess of making energy, you body looses some of it to heat and this increases the entropy of the surroudnings. As it turns out and increase in the heat introduced into a system often is associated with a increase in entropy (though not always!) and so it is usually a good idea to ask yourself "in what ways could i be loosing heat?" Many a time the answer will be either friction or heat lost durrring a chemical reaction. Anyways, just a quick little answer. I hope it helps some

i don't really know the absolutely correct answer, but i will give it a shot anywho multiplication is really just a easy way to add up numbers. That is, 6*2 = 2 + 2 + 2 + 2 + 2 + 2 . Right? Another way of looking at this (removing some of the abstract-ness) is as if i had 6 twos then how many do i have? Of course the answer is twelve. So then we can ask ourselves, if i have zero infinities, what do i have. Well, you have nothing. Since you have zero of them. So i would hazard to guess that 0 * infinity = 0 But like i said, i am not really a mathamatician, so this could be wrong.

This is some pretty wacky (yet really cool) stuff that was done with mouse brain cells. The basic outline is as such... 1) Get some mouse brain cells (aka; neurons) 2) Grow them on a plate so that the neurons make connections with eachother 3) Teach cells to fly an airplane Yeah, so maybe it was just a simplistic flight simulator, but still this is awsome. This has to be the coolest thing i have seen in a while (outside my discipline). Anyways, some articles follow... http:// http://www.napa.ufl.edu/2004news/braindish.htm http:// http://www.wired.com/news/medtech/0,1286,65438,00.html enjoy!

Sweet. Well, this is an interesting question... The first equation is just what was said in post #5. All it says is that your set of Psi functions are orthoganol. It is called a delta function and what it means is this; when n=m the answer for the integral is 1 when n != m the solution to the integral is 0 cool the second equation actually says something similare to the first. It is known as the dirac delta function and it is used to say basically the same thing, but for the discrete case (integrals are used in the continous case). It is a bit complicated to understand, but the idea is that if you were to try to represent the funcitons used in the summation by a curve the the area under the curve would be 1 if the functions were identical (x=x'), but 0 if they were not (x != x'). This is not entirely correct, but i think the dirac delta function is sort of hard to understand and explain (at least for me!). I am not quite sure what the equation means, physically, since it is hard to know what it is referring to when taken out of context Though i wish i could help. perhaps if you let us know what you were reading about in the first place with regards to q.m. then someone would have a better idea?

HUH? Do you have any sort of reference for that. i would find it interesting myself to read up on it. Thanks As to the original question, I am unaware of any plants that have stomata on top of the leaf, but who knows -- life have a way of supprising us. though i think for your class, a safe answer would be that they only occur on the underside -- someone correct me if i am wrong edit: The reason for them being on the underside is that the stomata are somewhat light activated and if they were on the top side, the plant would loose to much water

Well, first off, the earth and the moon revolve around eachother. It is just that the center of mass for this system lies quite close to the earth -- so it is conveinent for us to desribe it as the moon revolving around the earth. (though i guess it is all realitive and you could say the earth revolves around the moon -- but that is neither here nor there.) The point being that the moon and the earth both exert gravitational forces on eachother. But onto your real question I am guessing that you are asking something like "why does the air lie above the water and the land?" Wich might be a tricky question at first glance. However, it is akin to the question of "why do air bubbles rise in water?" For wich there is a good answer. This answer is; water is more dense than air. What that means, of course, is that in a given volume, there is more mass of water (or other liquids) than air (or other gasses). Since gravitational forces are a function of mass, we can see that for this given amount of volume the earth pulls harder on the liquid than on the gas. This is all well and good, but just because the earth pulls harder on liquids -- does it nessisariy follow that liquids must lie closer to the earth? Actually, yes. This has to do with the concept of energy. Gravitational potential energy is realted to two things. How hard the earth pulls on something (which we find by taking the acceleration of earth gravity and multipliying it by the mass of the object wich we are considering. this lets the energy scale with the mass of the object) and how high that object is. In the end this quantity of potential energy looks like this; Energy = (acceleration of earths gravitational feild)*(mass of object)*(height of the object) Ok, so the last thing we need to know, to answer your question is this; systems will always align themselves such that they have the lowest possible energy. OK, now we know all we need to answer your question, so lets take a look at it. Let us say that we have a given volume of gas and the same amount of liquid. ANd they are in a box wich is sitting on the ground. Both of these "objects" (liquid and gas) have a mass associated with them. The mass of the liquid is greater than that of the gas, by nessesity (since the liquid is more dense than the gas, and we have an equal volume of the two). The sytem inside the box now must oder itself such that it has the least amount of energy possible. We can see that by looking at the equation above for potential energy, that the liquid will have the most energy associated with it -- should it be at the same heighth as the gas. Thus, the liquid must reside at lower elevations, if the energy of the system is to be the lowest possible. Well, i doubt that explination is 100% correct or rigorous, but i think that it should at least get you thinking in he right direction. Hopefully if i am wrong, someone more in the know than I will correct me though. But at least for now, that is what i am thinking. Hope it helps. ;D

Intersting point. Do you know of any experiments in which people belived that they made solid hydrogen and it was not metallic? That would be interesting to read about. (i know very little about this expect for what i remember reading in HS) True. I am afraid that was bad writting on my part. Obviously' date=' you can have a liquid metal (ie. the obvious, mercury). I just thought that most of the experiments that had been done, people thought they made the solid state of hydrogen. But i could be wrong here too, i suppose (most likely). Again, perhaps my understanding may be incomplete, i thought it was theoretically possible to cool hydrogen enough so that metalic propreties emerged. But i could have just misunderstood the explination that i was given at the time :/ I am afraid that i do not quite understand what you are saying... It seems that the electron wavefuctions yeild a probability density that ALWAYS yeilds an area that is macroscopic -- in the sense that there is some probablility that an electron in your computer could be on the moon. The problem is that this would be extremely unlikely. What i thought happens in metals is that the electrons in the conduction band are delocalized over large areas and hence are free to move about the metal. This leads to the metalic properties of conduction and luster (caused by the surface plasmon), ect. So, it seems that all that is required is for the activation energy for electron transfer across the substance ---> 0 for the substance to be a metal. Is this correct? Now of course this will cause the electron to be able to be described by a wavefunction which has a probability density which remains significant over large volumes of the metal, but really it is this small activation energy for electron tranfer that is the root cause of metal. Would you agree? And the wavefunction is just a convienent way of talking about the effect that this low activation energy has on the electrons within the substance. Or is this all, crap? Feel free to tell me why. I am not really a physisist. I am kinda flying by the seat of my pants, so i would welcome some enlightenment on the subject Here, i mispoke again. SOrry. I meant to say luster -- which is a product of the surface plasmon (if i remember right) and, hence, is a property of metals. Ok, so people don't really know whether it is solid or liquid then? Or do they have a guess?? And i am assuming that you ment a large drop in RESISTANCE and an increase in CONDUCTIVITY, right? I think that would make more sense. Or am i completely way off base here? Anyways, thanks for your reply above -- always good to have people to keep you honest when you are lazy and to point out where you are wrong. ANd if you could correct me here where i am in error in my thinking that would be most welcome, thank you.

Well, that is a good question. Hydrogen is typically in its gas phase when you encounter it. As such, it doesn't really display the properties that metals have (ie. shiny, malleable, ductile, heat conducting, electrically conducting, ect.) As such, it is rarely reffered to as a metal. However, if one was to compress it (or cool it) enough, then it would condense and start to display these properties (at least the electronically conductive one -- kinda hard to see if the small short lived samples made so far are shiny ). As such, the term "metallic hydrogen" is commonly used to refer to hydrogen when it is in its solid state. For more information, the wikipedia is always a decent choice http://en.wikipedia.org/wiki/Metallic_hydrogen

yeah, i think the other posters have covered it nicely. The largest problems would most likely be; increadibly high pressures, horrible weather, and decently high gravity. At least that would be my thoughts. Though i thought that gas giants HAD surfaces. Am i just totally off base here. I thought they had a solid core surrounded by a gasseous layer?

Oh man, i can't belive that someone is trying to make liquid oxygen! That is nuts man. Best of luck -- i just hope you realize that saftey glasses will not help you at all. Explosions of liquid oxygen have been known to project glass shards through the saftey glass of hoods. And just so someone told you (though you might already know this) liquid oxygen will vigorously attack oils, grease and other organics. So just be sure that you keep the stuff away from that. OTherwise you will be in a world of hurt quite quickly. Now i am not trying to stop you (though i do think this is a horribly stupid idea saftey wise) i just would feel bad if i didn't mention a few things. That is all.

Well...yes and no. Yes, the ions can be stable for a long time -- provided that they do not encounter any other chemical species wich will oxidize/reduce them. So in a vacume ions produced by nuclear decay prolly do stick around for a long time. But here on the green hills of earth, they are most likely oxidized/reduced rather quickly. At least that would be what i would suppose would happen.