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Everything posted by rthmjohn

  1. I was having trouble finding a concise answer as to what types of iron compounds are found in the various foods that contain them. For instance, what is the form of iron found in leafy green vegetables vs. the kind found in red meat. Thanks in advance, John
  2. Does the principle of escape velocity apply to light? I'm a physics dummy, so I apologize if this sounds like a dumb question.
  3. So even though the probability of flipping heads 100 times consecutively is 1/2^100, you shouldn't necessarily EXPECT to flip tails after flipping 99 consecutive heads?
  4. For example, the probability of flipping heads with a two-faced coin is 1/2. Does the probability of flipping heads increase after flipping consecutive tails and vice versa?
  5. They say the chances of dying in a plane crash are 1 in 9 million. Am I correct in thinking that these chances increase the more you fly in airplanes? If that is true then how do you calculate your chances of dying in a plane crash after every new flight you board? That is, what is the formula for calculating this? Thanks, John
  6. I'm disappointed. I still don't see a nutrition or food science forum! I've got lots of questions regarding this topic and would like to be able to procure answers. Nutrition and food science are a part of science and should be included in SFN... but that's just my opinion (sigh...)
  7. Well mr. pangloss... what do you think should be done? Do you even think global warming is a problem?
  8. Global warming is obviously very real, but as long as these mega-corporations like Exxon Mobil and BP exist in the world, they will fight to prove global warming is a hoax. Enacting stricter regulations on emissions costs companies lots of money, and when you threaten to take awaysthese rich bastards' money you are guaranteed to see opposition from them. By the way... I know global warming is supposed to cause temperature rise, but I live in Indiana and it's supposed to be spring. It was in the 80's last week but over the weekend, temperatures dropped below the 20's (in degrees Fahrenheit of course). What's the deal with that?
  9. Hey guys, is there a Food Science/Nutrition forum? If not, I really think there should be considering the world's obesity epidemic!
  10. Allow me to rephrase my query; I was in an awful hurry when i first posted this thread and didn't bother to look at what I wrote. I know that sodium HYDROXIDE isn't and acid--hopefully I didn't sound too studpid there. What I meant to ask was why alcohols don't react with strong BASES and if this applies to all weak acids.
  11. I read in my text book that alcohols like methanol don't react with strong acids like sodium hyroxide. They will react, however, with organic acids. Why is this? Does this apply to all weak acids and strong bases?
  12. I am familiar with the ICE table. However, i did misword the problem (i didn't have a copy of the worksheet on hand when i started this thread). I have the worksheet now, along with all of the notes my teacher gave to solve this problem. Here is the actual problem my teacher gave us, WORD FOR WORD: Calculate the MOLAR SOLUBILITY of silver thiocyanate, AgSCN, in pure water and in 0.01M NaSCN. My teacher forgot to include the Ksp in the problem, but otherwise, I left NOTHING out in the above problem. She later wrote the Ksp for AgOH on the board as 2E-8. She then proceeded in trying to help us with the problem. She wrote the following reaction: AgSCN + H2O <==> AgOH + HSCN (does this really happen and is it necesary to solve this problem?) Then she wrote: 2E-8 = [Ag+][OH-] She substituted x's for the silver and thiocyanate ion concentrations and then solved for x as 1.41E-4. Then, for the second problem, she wrote: AgSCN <==> Ag+ + SCN- I didn't even understand what she did for the second half of the problem, but the funny thing is (and I just realized this) the problem asked for the MOLAR SOLUBILITY and she only solved for Ksp values of god knows what. Was any of the work she did necessary? Who knows, maybe she's right and i'm just plain crazy, but could anyone help me solve this problem now that I've got it worded right?
  13. Funny, because our teacher told us EXPLICITLY that because of the initial presence of SCN- would force us to do the following (and this is what our teacher wrote on the board): AgSCN: initial = 0, change = +x, equilibrium = x Ag+: i = 0, c = -x, e = -x SCN-: i = .01, c = -x, e = .01 - x
  14. Another one of my teacher's questions that she herself couldn't answer: Put the following in order from most ACIDIC to most BASIC. Assum aqueous solutions: KCN, KOH, KBR, CH3COOH, NH4CN, NH4BR I put them in the following order, but my answer was different from my teacher's: NH4BR, CH3COOH, KBR, NH4CN, KCN, KOH I argued my answer based on information she gave us in a lecture, so if anyone thinks my answer is wrong, my teacher is to blame. This is the order my teacher wrote: CH3COOH, NH4Br, NH4CN KBr, KCN, KOH When I showed her her own power point presentation that she used for this chapter, she couldn't disprove my answer and so I don't know which answer is the correct one. Can someone clarify? Here is the power point presentation my teacher used for this chapter if anyone cares to see it (I think there are numerous flaws in it): http://www.mccsc.edu/~jpresley/apchp15.ppt
  15. Wouldn't the presence of SCN- shift the equilibrium to the left and, thus, wouldn't the x's would be negative for Ag+ and SCN-? btw, I'm trying to post as many of my chem teacher's stupid questions as possible as proof that she is incapable of teaching college chemistry.
  16. This didn't make sense to me, and my chem teacher couldn't answer it either. She tried explaining to me for almost 15 minutes and still coulnd't come up with a solid and clear answer. The funny thing is that it was HER OWN problem: Calculate the molar solubility product for AgSCN in pure water, and then in a .01 molar solution of NaSCN. Could someone please, for the love of Pete, help me solve this? Yes, I am trying to get my chem teacher fired on account of her laziness, lack of chemistry knowledge, and her overall incompetence as an AP Chemistry teacher.
  17. on this same take-home test i am asked how to calculate the pH of a solution of H2CO3 being only given the ionization constants for: H2CO3 <==> H(+) + HCO3(-) and HCO3(-) <==> H(+) CO3(2-) I don't know where to start. Can anybody give a hand? Does it involve using the ionization constant for the overal reaction: H2CO3 <==> 2H(+) + CO3(2-)?
  18. hmmm.... my chem gave us this test with the following question: will Cl2O give an acidic, basic, or neutral solution when dissolved in water? Write a reaction to justify your answer. I'm guessing it will make an acidic solution because it would make HCLO, right? What's the equation for this reaction? I'm guessing Cl2O + H2O <--> 2HClO, but is this right?
  19. Okay, so this equation appeared on my last chemistry test. I wrote the following: NaF(aq) + HCl(aq) --> HF + NaCl(aq) Apparently my answer was correct except that I didn't know what phase the HF would be. I asked my chem teacher and she said she didn't know (sad huh?). So I have to resort to a science forum for the answer. What would the phase of the HF be? I thought it would be a gas.
  20. If anyone here has every smelled chlorine, it's a pretty nasty gas. I accidentally got a whif when making some. I was coughing for a few days after that. My suggestion: don't play with chlorine gas because it can kill you.
  21. You know, it's funny because our country (the US) is so concerned about promoting science and math in today's youth education (this is noticeable in today's high school curriculum). Chemistry is a branch of science and by banning the possession of chemicals, the government is simultaneously preventing youth exposure to chemistry at home and ultimately, perhaps, limiting the amount of possible future chemists in our country. It's also funny that the government would focus on such a small problem when there are much larger issues at stake. We home chemists are such a minority group that placing restrictions on us would make only the most minute difference in our nation's securtiy. Pushing for chemical restrictions, I think, is both a waste of the government's time and money. I think the government is just picking on us because we're an easy target.
  22. from what I've read, it sounds like aerogel is quite indestructable...
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