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  1. Metanoia

    Chemistry: Post your doubts here!

    We measure oxidation states in terms of each atom.
  2. Metanoia

    Chemistry: Post your doubts here!

    It is +1 before and after reaction.
  3. Metanoia

    Chemistry: Post your doubts here!

    Yes. H2 will reduce ketone and aldehyde, not sure why the ms says otherwise. You'll get the carboxylate salt RCOO- with Cu2O (red brown ppt) for Fehlings. And carboxylate salt with Ag ( silver mirror) with Tollens.
  4. Metanoia

    Chemistry: Post your doubts here!

    Yes, aldehyde.
  5. Metanoia

    Chemistry: Post your doubts here!

    product is ethanal C2H4O. (not ethanoic acid), as product is obtained by "immediate distillation under gentle warming" mass of ethanol converted = 0.7 (2.3) = 1.61 g moles of ethanol converted = 1.61/46 = 0.035 mol moles of ethanal produced = 0.035 mol mass of ethanal produced = 0.035 x 44 = 1.54 g
  6. Metanoia

    Chemistry: Post your doubts here!

    I'll correct this. The longest chain must contain the principal functional group. http://www.masterorganicchemistry.com/2011/02/14/table-of-functional-group-priorities-for-nomenclature/
  7. Metanoia

    Chemistry: Post your doubts here!

    The short answer to this is to realize that the types of bonding changes from ionic to covalent across the Period. The more in-depth answer is found in the paragraph below. From Understanding Advanced Physical Inorganic Chemistry http://www.worldscientific.com/worldscibooks/10.1142/7833
  8. Metanoia

    Chemistry: Post your doubts here!

    1 mole of H2 = ? mol of H atoms
  9. Metanoia

    Chemistry: Post your doubts here!

    Firstly, I've deleted my original explanation for Q18, I realized it was nonsensical after I reread it. Sorry about that. Q6. The chart shows that for every 1 isotope that has 10 nucleons, there exist 4 isotopes with 11 nucleons. This is the crucial interpretation you need to understand on the...
  10. Metanoia

    Chemistry: Post your doubts here!

    Sodium metals react with OH, COOH Sodium hydroxide react with COOH sodium carbonates react with COOH.
  11. Metanoia

    Chemistry: Post your doubts here!

    Erm, as I have explained. The 1st diagram is the incomplete answer. Students who produced the 1st diagram will only get 1 mark. Students who produced the 2nd diagram gets 2 marks.
  12. Metanoia

    Chemistry: Post your doubts here!

    Your diagram is fine. Its the same as the marking scheme.
  13. Metanoia

    Chemistry: Post your doubts here!

    Drawing the 2nd diagram will get you the two marks. If students only managed to draw the first diagram (incomplete) , they will get 1 out of the max 2 marks.
  14. Metanoia

    Chemistry: Post your doubts here!

    I think to be safe, I would want to see the rest of the original question to see the context.
  15. Metanoia

    Chemistry: Post your doubts here!

    Q6. From the relative abundance chart. Ratio of Isotope-10 : Isotope - 11 is 1:4 Q17. I saw the wrong question and explained for Q14. Use your data booklet and locate the elements that represent the four options. Fill them in here before I explain further. A. B. C. D. Q18. Again, us your data...
  16. Metanoia

    Chemistry: Post your doubts here!

    The truth is data of hot K2Cr2O7 on C=C is not readily available. So I am inclined to assume that it does not affect the C=C double bond unless some other info says otherwise. I doubt cambridge would require students to be aware of the answers unless the reaction is well-established.
  17. Metanoia

    Chemistry: Post your doubts here!

    Did the question ask for hot conc K2Cr2O7 or hot dilute K2Cr2O7 ?
  18. Metanoia

    Chemistry: Post your doubts here!

    Try to type out the corresponding answers next time. Q4. The N has a -3 charge. So it has 10 electrons. Q6. (1/5 x 10) + (4/5 x 11) = 10.8 Q17. Outer shell 7s2 7p6, total 8 outer electrons. Group 0. Q18. EDITED: ORIGINAL EXPLANATION IS WRONG. Q27. From data booklet. Tc has 43 protons. In...
  19. Metanoia

    Chemistry: Post your doubts here!

    Construct an equation for combustion of ethane. C2H6 + 3.5O2 ----> 2CO2 + 3H20 Heat of combustion (reaction) = heat of formation of products - heat of formation of reactants
  20. Metanoia

    Chemistry: Post your doubts here!

    ethanedioate ions is oxidised to CO2 and H2O (not found in the data booklet in this case).
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