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  1. Falconwing

    Chemistry: Post your doubts here!

    Oh well, I don't remember a thing! =P
  2. Falconwing

    Chemistry: Post your doubts here!

    There was something about the equlibrium constant increasing in the second reaction or something as well.. Do you remember it?
  3. Falconwing

    Chemistry: Post your doubts here!

    It came on today's paper, p11. Personally, I thought that option was wrong ( I don't really remember tho =P) but I'm not sure ^^
  4. Falconwing

    Chemistry: Post your doubts here!

    Sorry for the late reply, I doubt you need this anymore =P But, you only use the total abundance. For example if the relative abundance was 2 and 7, you will divide by 9.
  5. Falconwing

    Chemistry: Post your doubts here!

    (65 x 3 + 63 x 7) / 10 you divide by the total abundance, not 100
  6. Falconwing

    Chemistry: Post your doubts here!

    IE naturally increases across the period because the nuclear charge is higher, so Mg wil lhavve more IE than Na. It will also have more IE than Al, because Al has an electron in the outer p shell which has more energy and is also farther than the nucleus. (Mg outer shell => 3s2, Al outer shell...
  7. Falconwing

    Chemistry: Post your doubts here!

    The oxygen is in excess, methane for example won't burn in a 1:7 ratio with oxygen! So the oxygen is left and the volume decreases as more oxygen is used up.
  8. Falconwing

    Chemistry: Post your doubts here!

    It will be equal. It can't be greater or it will keep expanding until equal D? Besides, none of them are going to form aldehydes, they will form ketones. Carboxylic acids have higher boiling points bwecause of H-bonds. A and C form carboxylic acids, B forms nothing, and D forms ketone.
  9. Falconwing

    Chemistry: Post your doubts here!

    Is the answer D? A redox reaction surely doesn't occur, and Ammonia won't act as a base because there is nothing to neutralise...
  10. Falconwing

    Chemistry: Post your doubts here!

    2 moles of metallic salt react with 1 mole of sodium sulfite, oxidising sulfite needs 2 electrons. So, the original oxidation number of metal is +3, and there are two moles, so the new oxidation will be +2. RTP apparently Magnesium is second in it's group, so it would have the second smallest...
  11. Falconwing

    Chemistry: Post your doubts here!

    Reaction => Al4C3 + 4NaOH + 4H2O --> 4NaAlO2 + 3CH4. You'll end up at this if you try to balance the equation.
  12. Falconwing

    Chemistry: Post your doubts here!

  13. Falconwing

    Chemistry: Post your doubts here!

    Plug in the numbers from the table, for B, there are 5 I atoms in the right side. The rest of the equation fits too, check it out using trial and error. I suppose it is A. Balance the equations using trial and error. 1m of Butanoic acid completely combusts with 5m of O2. 0.1 x 13.1/1000 =...
  14. Falconwing

    Chemistry: Post your doubts here!

    The catalyst in experiment 1 could be faster (reduces activation energy more) than the one in 2. It has to do with speed, not yield. It would still stop at the same place as experiment 1, just taking more time.
  15. Falconwing

    Chemistry: Post your doubts here!

    It's complicated. http://www.chemguide.co.uk/basicorg/isomerism/ez.html#top
  16. Falconwing

    Chemistry: Post your doubts here!

    C isn't balanced. 4 O in reactants, 5 in products.
  17. Falconwing

    Chemistry: Post your doubts here!

    Why would it have 3 bonds? It has 4. (2 with one carbon, 1 with the top ethyl group, 1 with the bottom one) Besides, if it was B, then it would still possess cis-trans isomers.
  18. Falconwing

    Chemistry: Post your doubts here!

    You forgot 3d. Group II metal sulphate solubility decreases down the group, so Barium will give a white precipitate (insoluble) 3x10^-3 reacts with 2x10^-3 so 3 moles of TlNO3 reacts with 2 moles of NH4VO3. Each Ti will give 2 electrons, giving 6 electrons in total. V in Vo3- is +5, so those 6...
  19. Falconwing

    Marking scheme of 2002 physics p1

    http://freeexampapers.com/A-Level/Physics/CIE/2002-Nov/9702_w02_er.pdf http://freeexampapers.com/A-Level/Physics/CIE/2002-Jun/9702_s02_er.pdf use the ers
  20. Falconwing

    Chemistry: Post your doubts here!

    http://freeexampapers.com/A-Level/Chemistry/CIE/2013-Jun/9701_s13_qp_12.pdf Q25 - Answer is D. Why not C? Why do the double bonds not form with the carbon with OH group anyway?
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