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Quickie; what reaction

  1. Nov 11, 2007 #1
    [SOLVED] Quickie; what reaction

    I'm trying to find out what type of reaction this is.
    a drop of water is added to a small pile of chemicals in a dish, after a few seconds, a blue flame and smoke is produced.

    NH4NO3 reacts to form (with chlorine as catalyst) N2O and water

    the experiment is called oxidation of zinc, so another equation is Zn and NH4NO3 react to form ZnO and water.

    this is definitely a redox reaction right? but is there not a decompostition reaction first that allows the zinc to oxidize? so really, this reaction is oxidation reduction, catlyzed, and decomposition?
  2. jcsd
  3. Nov 11, 2007 #2
  4. Nov 11, 2007 #3
    but is the reaction soley redox, or are the steps different reactions as well.
  5. Nov 11, 2007 #4
    the drop of water I suspect is only to get the materials in close contact

    there seems to be no Cl2 (is a gas) around to promote the decompostion, otherwise it would already make the N2O and water (without the drop of water and the mixture would be wet)

    therefore the change in NH4NO3 must be due to the oxidation of Zn

    btw there is no NO2 in your 3rd equation

    so I would say it is a pure redox reaction with Zn being oxidized to ZnO and the N in NH4NO3 reduced to N2O
    Last edited: Nov 11, 2007
  6. Nov 11, 2007 #5
    hmmm, thanks, ill have to look into decompositon in more detail next time, merci.
  7. Nov 11, 2007 #6
    de rien
  8. Nov 12, 2007 #7
    1. H2O dissolves the salts forming NH4+ ions which make the solution acid.
    2. Zn reacts with NO3- (and probably even with water) now that the solution is acid; the products are Zn++ and NO, N2O, N2 or NH4+, depending on the relative concentrations of Zn and NO3-: NO and N2O when NO3- is in eccess, NH4+ when Zn is in eccess. Also N2O is generated by the heat decomposition of NH4NO3 itself:
    NH4NO3 + heat --> N2O + 2H2O.
    3. The heat generated in reaction 2. starts the reaction between solid Zn and solid NH4NO3 that now proceeds on its own.
    NH4Cl is used as catalist, but I don't know its exact functioning.
    Last edited: Nov 12, 2007
  9. Nov 12, 2007 #8


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    It could be that the NH4Cl reacts with the dilute acid to produce HCl. The HNO3 present would react with it producing an aqua regia type reagent.
  10. Nov 12, 2007 #9
    who new this was so difficult, i am trying to simplify it , thanks for yer help maties.
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