Jump to content

hypervalent_iodine

Administrators
  • Posts

    4586
  • Joined

  • Last visited

  • Days Won

    12

Everything posted by hypervalent_iodine

  1. I have to ask why you are holding onto this idea so fervently? The majority of tarnish-type blemishes on silver are in the form of silver sulfide. Ammonia will not remove silver sulfide. It is really that simple. Are there any other methods you would like to discuss?
  2. IIRC, sodium thiosulphite does the same thing. It's not the ammonium ion that's doing the work, it's the thiosulphate, which binds particularly well to silver.
  3. I'm not sure on the percentage. It varies with the alloy, obviously. It wouldn't be terribly much in comparison to the silver, however. Using ammonia is far less of an effective approach than using thiourea salts, etc., since it's not going to get rid of all the blemishes, only the copper impurities. Depending on how homogenous the distribution of copper is, you will likely get patchy removal. Why waste your time not doing the job properly/at all when bicarb and aluminium foil is a cheaper and easier option that actually works? I'm not sure what your point is with the ammonium thiosulfate. It's fat from being the same as ammonia solution, so it's hardly a comparison. I don't even think it would work that well, since ammonium thiosulfate is used for leaching silver and gold, not cleaning it. I mean, if your objective is to destroy the object then I guess it's what you want. Did you mean the thiourea salt? Edit: You may be interested in this paper.
  4. Both of you, stop with this ridiculous ad hom back and forth. Greg, ammonia does not remove Ag2S, it removes Cu2S. Copper is a common impurity in silver, especially sterling silver, which is why ammonia is often quoted as being useful by people who don't really know what they're doing.
  5. I don't think that someone doing a science fair project is going to have access to a HPLC. I like the idea of using quantitative spectrometry, though I would still question whether or not the OP has a UV-Vis available to them. Another way to test for it with UV-Vis is by reacting the glucose with 3,5-dinitrosalicylic acid. This oxidises the glucose and reduces the DNSA to 3-amino-5-nitrosaliclic acid, the latter of which has a distinct red-brown colour. You would need to do a standards curve, of course, but that's no real issue. I tutored a first year prac where students tested the amount of sucrose in cereal and in soft drink by first hydrolysing the sucrose present and then reacting it with DNSA and it worked quite well (ignoring the obvious contributions to their readings by other sugars already present in their samples). That would depend on what equipment they have access too. Separating the cellulose from the cellulase is a lot more involved than simply filtering off the cellulose/cellulase precipitate to give you a glucose solution; if you can't do a column or even a liquid-liquid extraction (which may also work), the former method becomes much less feasible (and would still be a bit more difficult than trying to simply isolate the glucose).
  6. Is it pure cellulose? By sugar, I assume you mean free glucose monomers? Cellulose is a sugar polymer, so you should be a little clearer in what you want. Separating the glucose should be fairly easy on account of the distinct solubility profiles. I am also curious as to what exactly you mean when you say, 'cellulose solution'. Cellulose dissolves in very little of anything without chemical modifications.
  7. Moved. Jade, please be aware that the science sub forums are for mainstream, accepted science only.
  8. Moving this to speculations, where it belongs.
  9. We really do have it tough here. Today was a sunny 79oF and I just couldn't decide which beach to go to. In the end I gave up, went to a park along the riverfront and read a book under a tree. I often wonder how I manage to cope under such awful conditions.
  10. I have returned to the realms of civilisation.

    1. Show previous comments  10 more
    2. hypervalent_iodine
    3. JohnB

      JohnB

      Woodford? Awesome, and not as wet as last year. ;)

       

      Did you happen to see the Funky Faeries people by any chance? They have the most stunning hand made oil burners.

    4. hypervalent_iodine

      hypervalent_iodine

      Ha. Yes, it was by far the driest Woodford I have attended. In fact it was wonderful, weather wise. Only the occasional brief shower.

       

      I think I may have looked at their stall. I was there the whole week doing volunteer work, so I'm pretty sure I saw most everything there was. My wallet can testify to that.

  11. Thank you Greg, Arete already clarified it for me. I will readily admit to not being a biologist, though I do have some idea of how viruses infect and sustain themselves within their host, albeit not a comprehensive one. And yes, you might want to check your facts on the phylogeny front.
  12. It will likely contain cis-fatty acids, so it will not be fully hydrogenated. You are right to assumer that fully hydrogenated fats will typically be solid at or around room temperature. There may be some hydrogenated oils in vegetable oil, I'm not sure, but the majority of it will be cis-fatty acids.
  13. Short answer is yes. Sorry I don't have time to go into that more right now.
  14. And the same to you and yours! Thank you for the message :)

  15. That really doesn't make any sense. The diseases themselves are caused by infectious vectors such as bacteria or viruses, not the rats/insects themselves. Even ignoring that, how would it make sense that a disease carried by an organism closer to us evolutionarily than another would be more likely to make us sick? I'm really not following that logic.
  16. I'm sorry, but molten salts + HF? This isn't really something you should be attempting at home and is considerably less practical than the conventional route you've cited. How high is very high, anyway? And for the love of Woodward, start reading some papers published after last century.
  17. The correct mechanism is the one in which the bromonium ion is formed:
  18. It's sad the damage idiots like What's-her-face Carson can do in combination with a general lack of education and skepticism amongst the public.
  19. A small aside. My understanding was that such nations were permitted use of DDT for the prevention of malarial disease, albeit restricted. Last time I checked that was for a presentation about 4 or 5 years ago, though, so I may be wrong.
  20. In fact, I would say that P(thread move) = 1 Greg, though I would normally steer clear of political threads, I would ask if you actually have some sources to back up some of your more recent claims; specifically: Please read this article so that you might come back with a more informed opinion on the matter. From the article: Enforced "fertility control" of the populations of developing nations is not the solution, Greg. It isn't practical, it generally isn't ethical and in the long run, it doesn't really solve the problem, it only treats the symptoms.
  21. Edit: Sonryu, I am happy to go into a bit more of an explanation regarding the experimental protocol and reasons behind why we do certain things if you'd like. Knowing your background, I have a feeling you're going to ask anyway
  22. It would not be advisable for someone else to end you their lecture notes unless they are already freely available. A quick Google search gives this: en.wikipedia.org/wiki/First_law_of_thermodynamics And if you have access to it: http://pubs.acs.org/doi/abs/10.1021/ed079p193 If you have specific questions, please ask them. You are asking for a lot of information and it's not exactly fair that you ask members here to Google and regurgitate what you could quite easily Google yourself.
  23. It would be considerably easier if you could tell us what you do know and what you don't understand, rather than having someone splurge out pages of information.
  24. The easiest way to do it is just to extract it from instant coffee. I used to tutor a first year prac where students did exactly that. They dissolved about 10 grams in water and did a liquid-liquid extraction with DCM, dried over MgSO4 and would get about 1gm or so of crude caffeine. Recrystallisation with minimal hot ethanol returned about 0.1 - 0.2 gm pure caffeine for most. A more skilled hand would do a bit better, but it's not really that bad and it certainly is an easy way to do it.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.