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Search results

  1. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    :)
  2. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Yes you can say that displacement reactions are redox since one element is oxidized and the other is reduced. No extra ions are formed. No problem :)
  3. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Knowing about carbonates is not part of the syllabus but.. SO4 2- NO3 - CO3 2- OH- Cl - Br - I - Here is the list. Iodide ions are most readily discharged whereas sulphate and nitrate are not easily discharged. Besides, in any event if nitrate, sulphate or carbonate is present then hydroxide...
  4. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    For 7, it's (d) Redox, since the zinc replaces the copper (II) sulphate (since it is more reactive) and reduces it whereas the zinc itself gets oxidized and hence a redox reaction. For 9, well iron (III) is the highest oxidation that an iron element can reach so potassium manganate (VII) cannot...
  5. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    You nailed it! :) Yeah, we only need to know about molten and aqueous solutions and about bromine, iodide, chloride, hydroxide, nitrate and sulphate and how concentration affects them but there is no harm in learning more is there? :)
  6. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Yes and ammonium carbonate.
  7. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Carbonates are mainly insoluble so they're relative discharge is not considered mostly.
  8. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    They are next to sulphuric acid in discharge series. They discharge in preference to sulphate ions but don't discharge in aqueous solutions since hydroxide more easily discharges. Hope that helps :)
  9. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Do you know why sulphuric ion does not discharge? This is because it is very reactive and forms sulphuric acid again after ionising. Hence, the quantity of hydrogen is in terms only double that of hydroxide (from H2O) but in actual experiments it would be slightly more than double because of...
  10. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    That is because they are very reactive and are the hardest to discharge, they react back and form sulphuric acid again.
  11. Saad Mughal

    Maths, Addmaths and Statistics: Post your doubts here!

    No problem :) You find substitution easy, I find this easy, it is a matter of a persons choice as to what method he adopts. Anyways, trig. subs. won't come. I'm sure of it.
  12. Saad Mughal

    Maths, Addmaths and Statistics: Post your doubts here!

    Ok, so when differentiating 7x, what do you do, please elaborate. :)
  13. Saad Mughal

    Maths, Addmaths and Statistics: Post your doubts here!

    My friend, this is not Integration by Parts! I know it is easier with substitution but this can also be done directly using the Integration method easily.
  14. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    It's kinda easy :p We know that the sulphate ion is not given preference of discharge over hydroxide (in other words, sulphate ions are never discharged) therefore hydroxide ions, i.e. oxygen gas (negative ion) will give off at the anode (tube X) and the other Hydrogen ions (H+) will form and...
  15. Saad Mughal

    Physics Help.. Again.

    It's a trend. It happens with everyone. Only few teachers are those who give advice and help exactly according to CIE.
  16. Saad Mughal

    Maths, Addmaths and Statistics: Post your doubts here!

    That's what I was confused about!
  17. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    No problem. :)
  18. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    If it hadn't included the word useful then we would have added Heat Energy (Thermal Energy) since this is a common day example that our cellphones heat up when they are being charged this shows that energy is being WASTED in form of heat. By useful they mean that the energy conversions that are...
  19. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Your first part is correct and it is the ANSWER but the second part is incorrect and is not even required, Electrical energy actually changes to chemical energy and thermal (heat) energy not sound energy; besides, the question asks for USEFUL energy outputs.
  20. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Since they are asking for USEFUL energy outputs, the answer would simply be: Electrical Energy from the mains changes into Chemical Potential Energy stored in the battery, as follows: Electrical Energy ----> Chemical Energy.
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