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rthmjohn

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Everything posted by rthmjohn

  1. Just wondering... is it possible to demagnetize, say, a neodymium magnet? May sound stupid, but I'm just curious... (by demganetize I mean completely remove is magnetic field).
  2. I was thinking the same thing. And it's stupid that you would try to find the calorimeter constant of a BOMB calorimeter by adding water to it. It would make more sense to combust a substance of a known heat of reaction, but like I said, my teacher is RETARDED!!!!!!!
  3. So we did this lab in class in which we inserted a temperature probe into various samples liquids, removed the probes, and then measured the temperature drop over time of the evaporating liquids. Two of the liquids we had to test and compare were n-heptane and n-hexane. According to my predictions, the heptane, due to its longer chain structure, would have a greater instantaneous dipole, which would mean greater intermolecular attraction and higher boiling point. This would have suggested that there would have been a greater temperature drop in the heptane than the hexane because more energy would be required to separate the heptane molecules. The experiment proved me wrong; the heptane had a lower temperature drop than the hexane but took longer to evaporate. I can understand why it would take heptane longer to evaporate, but why was the temperature drop in the hexane greater then the heptane? The same results occurred in the testing of the other liquids where I predicted that one compound would have a higher temperature drop but was wrong. I asked my teacher about this, and she was baffled because her predictions were the same as mine... Can anybody please explain?
  4. But, jdurg, she gave us this formula to solve the problem (and yes she included the parenthesis too): q(hot water) = - [q(cold water) + Calorimeter constant * DeltaT] Doesn't this include energy lost to the calorimeter? She said that heat was lost to the calorimeter. The answer she arrived at was about 69J/degree C, which seemed a bit low...
  5. My chemistry teacher is so retarded! She tried explaining this problem to me, but I think her logic was flawed. Could anybody please help me solve it? I don't mean to sound like all those other people who try to get others to do their homework. I actually did attempt this problem, but I think more information is needed. Here it is: Determine the calorimeter constant for a particular bomb calorimeter by mixing 50.0mL of water at 25.0 degrees C with 50.0mL of water at 60.0 degrees C. The final temperature attained is 40 degrees C. Any help will be greatly appreciated!
  6. This has to do with the fact that the two substances are both water and, thus, have the same specific heat, which means that, regardless of whether you pour the water into the boiling water or heat it separately, the time required to bring the water to boiling will remain the same. When you add cold water to boiling water, the the cold water gains heat, but the boiling water loses the same amount of heat, which means there is no net increase in temperature. And like neonblack asked: You don't have water or a saucepan?
  7. Are you kidding? Maybe you should try it for yourself. You should actually observe a steady reaction between rust and HCL. The rust will dissolve and the solution should turn green. The overall reaction is as follows: Fe2O3 + 6HCL --> 2FeCl3 + 3H2O
  8. What exactly did you mean by this? I'm guessing you just made a mistake and meant to say that P forms -3 anions because K only forms +1 cations. Or did I misunderstand you?...
  9. I had a little debate with my teacher over this test question: One of the van der waals constants, a or b, can be correlated with the boiling point of a substance. Specify which constant and how it is related to the boiling point. Any comments? I thought it was b (atomic/molecular size), but apparently I was wrong...
  10. (hope this doesn't sound retarded) My nerdy godfather once told me that you only get bad body odor in your armpits when you're nervous, but that sounds a bit off. Can anyone verify this (or falsify it)?
  11. Wouldn't it be more appropriate to ask why the electron affinities of group 2 elements and nitrogen are positive? Like I said, the process is endothermic, so wouldn't a positive value make more sense in describing the process?
  12. I'm sorry, I can't believe I posted that (trust me, I DO know what electron affinity is). Yes, electron affinity is the ADDITION of electrons. My bad, but the same holds true for the positive and negative values. Positive values mean endothermic and negative mean exothermic. Be careful how you read certain tables, though... Some tables erroneously list affinity values as positive when they should actually be negative and vice versa. ie. I'm sure Nitrogen is actually positive since it requires more energy to add an electron.
  13. You also forgot to mention the noble gases. The reason for this is because the process of removing electrons from the specified elements requires energy. The values are in Kj/mol of the substance. A negative value means that the removal process gives off energy.
  14. Did you read the unitednuclear page thoroughly? It says the magnet would be near frictionless. I'm pretty sure the friction between the fluid and tube would be greater, but I could be wrong.
  15. This has always made me wonder, do bacteriae, being nothing more than cells, have any sort of intelligence?
  16. Don't dentists use nitrous oxide to put patients under when doing surgery? If so, the effects seem to last longer than 30 seconds. And the effects of most drugs are overrated.
  17. Speaking of engine valves, jdurg, have you asked your friend what brand he used?
  18. THAT, definitely is satanic! This is exactly the stuff that I feel should be banned. These films are absolutely immoral and outrageously sexist. I also believe that this form of pornography should be distinguished from other less sexist and immoral forms.
  19. I would imagine so. Isn't the mass gain due to the conversion of kinetic energy into mass?
  20. just how expensive are these engine valves, though? Do you think it would be worth buying one for the amount of sodium that you get?
  21. Seems to me porn is a natural part of society, although it was most definitely founded by men, and it seems like most people turn out alright. I've read somewhere that porn can relieve stress and allow for relaxation (hope that doesn't sound too weird). And as for the actors/models in porn, maybe they are psychologically harmed, but they, or paid models at least, chose that career. I mean, look at Brianna Banks or Jezebelle Bond, or Mimi MacPherson, or any of the Playboy centerfolds... I'm sure they all chose to do what they do, and any psychological harm is probably just compounding preexisting issues.
  22. Actually, I think porn dates back to the Persians.
  23. Seeing as most problems caused by pornography are just perpetuations of preexisting problems in an individual, then porn really shouldn't be a big deal in our society. Since there's hardly any evidence of it destroying the minds of large populations of people, I think that the issue is more moral than psychological. When you think of it, though, a large majority of porn consists of paid pornstars, or people who willingly engage in the filmmaking. Granted there are many sad cases, especially in other countries, in which desperate women are lured by false promises of a well paying job and later forced into pornography/prostitution. I think the exploitation of struggling women should be the real issue.
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