Jump to content


  • Content count

  • Joined

  • Last visited

Community Reputation

0 Unknown

Profile Information

  • Country

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. booji

    Physics -- Viscosity

    Google "Physics Classroom" or MIT Physics OCW - you should find a plethora of resources there.
  2. [quote name='silverks' post='20478' date='Jul 24 2008, 10:34 AM']Ok, 5g of that white powder obtained from 6g of tea leaves is definitely NOT caffeine. In all probability the amount of caffeine you should get is in the scale of milligrams. For 6g of tea leaves, you should be able to get around 30 to 60 milligrams of crude caffeine. If that white-ish powder is indeed the sodium sulphate, then sublimation is required to separate them. Caffeine is known to undergo sublimation at around 178 C while anhydrous sodium sulphate will melt at extremely high temperature (844 C), so you should be able to easily separate them by sublimation technique. However, you should not have gotten that much white-ish powder in the first place. I've done caffeine extraction multiple times before and managed to extract crude caffeine (what you call the white-ish powder) from 0.004g to 0.020g, depending on the brand and type of tea leaves used. If you could list out your extraction methods I may be able to help you out further.[/quote] First of all, if you have access to an IR, UV-Vis, or NMR spec, get a spectra of the white powder that you have extracted. If indeed caffeine is present you should see a characteristic pi --> pi* transition in the UV-Vis spectrum, and similarly you should see characterisitc C-C stretch in the IR spectrum. This will confirm if you have indeed extracted caffeine. After that, you could try extraction of that solid with various organic polar solvents (acetonitrile comes to mind). Your best bet would be to consult the literature to see which organic solvent would work best. I am sure there are a plethora of articles on SciFinder of CSA, etc.
  3. Its usually on or around the 6th of July.
  4. Excellent scores here guys! Keep up the great work!
  5. booji


    [quote name='Mark' post='15795' date='Apr 30 2008, 06:52 PM']How can u get accepted to a uni without predicted grades?[/quote] US schools don't really "care" about your IB final grades. They really look at the grades you recieve on your high school transcript. That being said, if you want to receive any credit for your IB work, you need to have a high grade (generally a 6 or 7 in HL subjects)
  6. Haha - I agree ezex. Amazing school. By the way, it doesn't snow thaaaat much in Boston .
  7. BIO-AQUA, I noticed you have some of the US professional school entrance exams, i.e. LSAT, but there is one more I think you should include - the infamous MCAT: The MCAT is an exam administered by the American Association of Medical Colleges (a division of the American Medical Assosication). It is required of almost all prospective medical school applicants who aim to seek admissions at a US or Canadeian Medical School. As of 2007, the exam is adminsitered solely as a computer-based test (CBT) with scores available within about 1 month of testing date. The exam consists of four sections: the physical sciences, PS, which tests concepts in general (or inorganic) chemistry and general physics; verbal reasoning, VR, which tests analytical reasoning; writing sample, WS, which tests thoroughness of written communication; and lastly, the biological sciences, BS, which tests general biology and organic chemistry. The PS, VR, and BS sections are scored on a scale of 1 through 15 and the WS on a letter scale ranging from J through T, all for a maximum possible score of 45T (which as far as I know, has not been achieved yet). The MCAT is generally taken during the junior year (i.e. third year) of the undergraduate curriculum, prior to applying to medical school.
  8. I have read One Hundred Years of Solitude (Cien Anos de Soledad) in English and Spanish and its a great novel, albeit really long. You have to really appreciate Marquez' use of magical realism in that novel.
  9. Yeah I read that book in Spanish for AP Spanish Literature and it was excellent. If you read spanish, you should check out some of her other works...(probably available in English too, but something is always lost in translation )
  10. booji

    Chem HL?

    Its funny you said that. We have really poor teachers here, and thats exactly why I was implying that one should teach topic 1 to onself (i.e. assuming by default that the teachers were useless...LOL) But stochiometry is quite straightforward.
  11. option H is quite fun actually, and my ambition to go into medicine/biomedical sciences sort of butresses the intrest. I actually took a college-level course in neurobiology/electrophysiology so the nervous system comes quite easy, its remembering the complement fixation, clotting cascades, and basic pharma which is difficult.
  12. We have a similar problem in our school, except in this case, its the IBC who also teaches biology. Basically, her daughter is in our class as well, and she is taking BIO HL with her mother as the teacher and as the IB Coordinator. I have no doubts that the daughter gets special consideration. Its interesting because among the HL students, every single person, except the daughter, failed the mid-term and the daughter got a near perfect score. The daughter is extremely lazy and produces far shoddier work than anyone else. Since the teacher is also the IBC, everyone is "afraid" to make a formal complaint since the teahcer is known to hold grudges. I was wondering if there was any IB bylaw that prohibited teachers/IBCs from assuming that position when their own children were in IB. Certainly creates a huge conflict of interest.
  13. In my year we have about 22 student doing either Math HL or SL. Of those, about 9 are doing HL and 13 are doing SL. However, according to my math teacher, about 50 % are going to drop a level ( so Math SL to Math Studies, and Math HL to Math Sl)
  14. IB list for World Lit books? Do you have any idea where I could find this? I have asked my English teacher, but no response. Also, what are your opinions of The Stranger by Albert Camus? (it’s our summer reading book). Most of the books mentioned ( i.e.: Death of a Salesman, Macbeth, etc) are the ones we've already read in high school; have you ever been in a similar situation, and read the book again in the IB years? I love those books, though I wouldn't mind reading others: D Thanks!
  15. I'd definitely recommend the IB Diploma program! From the IB alumni of my school, aside from adapting in the beginning, they claim that the IB was a life-changing experience, even if they did fail the diploma. IB prepares you for college life, in my opinion, and teaches you valuable skills such as time management, prioritizing, and being a balanced student (not just focused on academics, being a holistic student with CAS). If you can handle the course work, I'd say go for it. Try it out, and see if it works!

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.