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Chemical equations

  1. Jul 5, 2009 #1
    Hey guys, I nd sme help with sme chemical equations that I hve. I've tried different sources but they seem to be contradicting each other. Please help.

    1. When Mn(NO3)2 is heated, MnO2 and a brown gas J are formed through decomposition. What is gas J?

    I tried to cancel out the similar element that were in MnO2 from Mn(NO3)2 to get N2O4. However, is that gas J or is it 2NO2?

    2. MnO2 is added to H2O2. A colourless gas P was released and was found to rekindle a glowing splinter. What is gas P and construct a balanced equation to show the chemical reaction.

    I knw that gas P is Oxygen but I'm not sure abt the other products so I'm not rlly sure abt the balanced equation. I think this is it though;
    MnO2 + 2H2O2 --> 2O2 + 2H2O + Mn

    It shld be correct. Any help is rlly appreciated.
     
  2. jcsd
  3. Jul 6, 2009 #2
    1) J is indeed NO2. (NO2 can dimerise to give N2O4, but that's besides the point)

    2) I think you'll actually be getting Mn(OH)2 out of it, but I could be wrong.
     
  4. Jul 8, 2009 #3
    Hey there, I don't rlly think Mn(OH)2 is formed cos. I'm quite sure that H2O is formed. However, I'm not rlly sure. Thnks for the help though.
     
  5. Jul 8, 2009 #4

    Borek

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    Staff: Mentor

    MnO2 just catalyze the reaction - it doesn't change.
     
  6. Jul 8, 2009 #5
    Wait a minute, so MnO2 remains as a product? Pls be clearer, by possibly suggesting another balanced equation if mine is wrong. Thanks.
     
  7. Jul 8, 2009 #6

    Borek

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    Staff: Mentor

    Hydrogen peroxide decomposes to water and oxygen.
     
  8. Jul 8, 2009 #7
    Woah, so the balanced eqn. is actually;

    MnO2 + 2H2O2 --> O2 + 2H2O + MnO2 ?
     
  9. Jul 8, 2009 #8

    Borek

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    Staff: Mentor

    Just 2H2O2 -> 2H2O + O2

    You may put MnO2 over reaction arrow, to signal catalyst presence.
     
  10. Jul 9, 2009 #9
    K, thnks vey much for the help.
     
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