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  1. S

    Chemistry P1 Challenging Questions Preparation

    2NaBr + Cl2 -> 2NaCl + Br2 You know that Cl can displace Br2?
  2. S

    Chemistry P1 Challenging Questions Preparation

    Answer: A because there is only 6 electrons in the outermost shell. 1 electron each from F, and since its electronic configuration is 2,3 theres only 3 electrons in its outer most shell so it can only bond with 3 other electrons
  3. S

    Chemistry P1 Challenging Questions Preparation

    Q2) PbCl4 + 4NaBr -> 4NaCl+ PbBr2 + Br2 Find the moles of PbCl4 which is 6.980/R.F.M of PbCl4 The react 1:1 ratio therefore Moles of PbCl4 x (79.9x2) = Mass of Br2 which option C
  4. S

    Chemistry P1 Challenging Questions Preparation

    for option "C"( sort of correct): Cl is more electronegative so C moves towards Cl -->.. and O is more electronegative compared to C so C's dipole moves towards <--.. But this is still a polar molecule as "O" is more electronegative compared to C.. hence having a dipole Answer is "B" because...
  5. S

    Chemistry P1 Challenging Questions Preparation

    Answer : D If you can't read my handwriting sorry: The "H" from NH3 and "Br" from the other molecule get removed( something like condensation)
  6. S

    *Biology Paper 5 tips*

    Could someone please explain to me what it means by "state the null hypothesis"
  7. S

    A level Biology: Post your doubts here!

    What do we need to know for bio tech? do we need to remember the fermeter ? like labelling aswell as functions?
  8. S

    A level Biology: Post your doubts here!

    Hormone HCG(Human chronic gonadotrophin) is produced by the chorion which is a layer of cells growing out from the embryo into the uterus wall (placenta) It circulates in the mother's blood to reach ovaries by the time her period should normally start HCG has already built up to a high level...
  9. S

    A level Biology: Post your doubts here!

    So basically K+ channels in the plasma membrane of the beta cells first open causing K+ to diffuse out. Which then causes the inside of the cell to be -70mV to compared to the outside. If glucose levels are high, glucose enters the beta cells. THe glucose is then phosphorylated then metabolised...
  10. S

    How was Chemistry P34?

    I dont think it really matters
  11. S

    A level Biology: Post your doubts here!

    Using examples outline the need for energy in living organisms. I'm not sure what to write..
  12. S

    How was Chemistry P34?

    are you talking about the shape of your graph?
  13. S

    Bio A2- Notes on Respiration, Photosynthesis & Plant Hormones

    Thank you! Do you have any notes on gene tech and bio tech?
  14. S

    A level Biology: Post your doubts here!

    Thank you so much!
  15. S

    A level Biology: Post your doubts here!

    What does it mean by "photorespiration is avoided"?
  16. S

    how was chemistry paper 22

    yep!
  17. S

    how was chemistry paper 22

    Al is also correct its just that it conducts electricity poorly
  18. S

    how was chemistry paper 22

    Do you think S is right? since it forms SO2 which is toxic?
  19. S

    how was chemistry paper 22

    i wrote Al
  20. S

    how was chemistry paper 22

    what about a toxic gas?
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