Help with Chemical Equations - Mn(NO3)2, MnO2, H2O2, O2

[DarylMBCP]

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.

 

[queenofbabes]

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.

 

[DarylMBCP]

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.

 

[Borek]

MnO₂ just catalyze the reaction - it doesn't change.

 

[DarylMBCP]

Wait a minute, so MnO₂ remains as a product? Pls be clearer, by possibly suggesting another balanced equation if mine is wrong. Thanks.

 

[Borek]

Hydrogen peroxide decomposes to water and oxygen.

 

[DarylMBCP]

Woah, so the balanced eqn. is actually;

MnO₂ + 2H₂O₂ --> O₂ + 2H₂O + MnO₂ ?

 

[Borek]

Just 2H₂O₂ -> 2H₂O + O₂

You may put MnO₂ over reaction arrow, to signal catalyst presence.

 

[DarylMBCP]

K, thnks vey much for the help.