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  1. HubbaBubba

    Chemistry: Post your doubts here!

    Sorry for the late reply, I had to revise a topic in chemistry. BTW I did Summer 2011 not Winter but I'll help you q4 - It says there's 96kg of Hydrogen leftover, so 120-96 = 24kg of H2 was used in the reaction. no. of moles of H2 = 24kg/2 = 12 moles. N2 + 3H2 ---> 2NH3. Ratio of...
  2. HubbaBubba

    Chemistry: Post your doubts here!

    With credit to h4rriet who helped me with this earlier :) You're taking the Kc for the reverse reaction, so you'll take the reciprocal of the forward reaction. Then, look at reaction II, and you'll see that all the moles have been divided by 2. Therefore you take the square root of the...
  3. HubbaBubba

    Chemistry: Post your doubts here!

    The last one is from 2003 november. The rest are from 2011 paper 12
  4. HubbaBubba

    Chemistry: Post your doubts here!

    Nope it's B. Sulfur trioxide is acidic, and ammonia is a base so that's an acid-base reaction. If you check the equation no oxidation or reduction takes place in any of the elements.
  5. HubbaBubba

    AS (Biology) P1 MCQs Preparation Thread.

    q29 - water potential is most negative when it has the most sucrose concentration. Since sucrose is produced at the leaf, B would be the correct choice. A cannot be correct because if the mesophyll cell was indeed the most negative, water would pass into the cell which is not what the cell...
  6. HubbaBubba

    A level Biology: Post your doubts here!

    q16 - Statement 4 is completely wrong, osmosis only involves water molecules. Therefore the correct answer would be C. q40 - It cannot be B, because that is the intensity of light. You can tell, because it increases in summer, but decreases in winter, it's highest peak in the middle of summer...
  7. HubbaBubba

    A level Biology: Post your doubts here!

    Water does not necessarily have to pass through the plasma membrane itself. It can pass through the pores of the cell membrane as well and still be counted as a symplast pathway. It's not B or C because they are not complete symplast pathways. Any water that passes through the vacuole of a cell...
  8. HubbaBubba

    A level Biology: Post your doubts here!

    q8 - It cannot be B because it's not describing anything about the structure and it's function. The correct answer is D because they are insoluble to not affect osmotic properties of the cell. q33 - This one is supposed to confuse the candidates. It's not asking if the tidal volume increases...
  9. HubbaBubba

    Chemistry: Post your doubts here!

    I did it a bit differently and got the correct answer as well. 72/24000 = 0.003 moles of carbon dioxide. mass of carbon = 0.003 * 12 = 0.0036g. 0.144 - 0.0036 = 0.108 g of X (Aluminium) left. 0.108/27 = 0.004 of Aluminium Ratio of Al to C 0.004 : 0.003 4 : 3 therefore it is Al4C3
  10. HubbaBubba

    Chemistry: Post your doubts here!

    Can somebody explain those? q23 - What do they mean by mole fraction is 0.5? How does that affect the identity of X? q33 - Why is it 1? Why isn't it 2? q35 -How does nitrogen undergo a redox reaction? It only goes from +3 to 0. q31 - Where do ionic bonds form? All elements present are...
  11. HubbaBubba

    Chemistry: Post your doubts here!

    I did draw an ICE, but I don't understand how they got 4(b-x) at the bottom. I just got (b-x)^2
  12. HubbaBubba

    Chemistry: Post your doubts here!

    Sorry misread the ms :whistle:
  13. HubbaBubba

    Chemistry: Post your doubts here!

    I wrote Na for 30, but the answer is CH3COOH. I have no idea why, as that would give an ester, and that has two O atoms.
  14. HubbaBubba

    Chemistry: Post your doubts here!

    More help please! :coffee:
  15. HubbaBubba

    Complete AS Biology Notes (P1 and P2)

    Bump! Nearly forgot about this. In case people need more revision before Wednesday :)
  16. HubbaBubba

    Chemistry: Post your doubts here!

    Thank you, it makes much more sense now! If I could like your posts more than once, then I would :)
  17. HubbaBubba

    Chemistry: Post your doubts here!

    Thanks for answering all those questions! My main problem in the fourth question is that I don't understand how it can produce two alkenes? I understood the third option though.
  18. HubbaBubba

    Where can I get AS biology past papers from 1995-2000 ?

    Only people with older siblings that took the exam in 2006 or earlier have those past papers. It doesn't really matter much, the syllabus is really different after 2004 as they have taken many things out of the syllabus. Just do from Nov 2002 to Nov 2012 and I'm sure you'll be fine.
  19. HubbaBubba

    Chemistry: Post your doubts here!

    I have a couple of questions I don't really understand, could anybody help? :)
  20. HubbaBubba

    my grade ?

    Math it's either an A or a very high B (Most likely A). AICT - A definite A
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