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montinho
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PostPosted: Sun Sep 18, 2011 8:29 pm    Post subject: Oxidation of Manganese Reply with quoteFind all posts by montinho

Alright I am doing a lab about oxidation of manganese I need to find the products of these reactants and balance the chemical equation. This is what I have.


[b]THIS CHART[/b]
[u]Compound [/u] [u]Oxidation # of Mn[/u]
KMnO4------------------+7
K2MnO4-----------------+6
MnO2--------------------+4
MnSO4-------------------+2
MnCl3--------------------+3


1.)KMnO4+H2SO4+NaHSO3-->

2.)KMnO4+NaOH+NaHSO3-->

3.)KMnO4+NaHSO3---->

4.) KMnO4 + EDTA + MnSO4(s)---->

what role did EDTA play in this reaction?
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montinho
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PostPosted: Mon Sep 19, 2011 5:37 pm    Post subject: Reply with quoteFind all posts by montinho

post please!
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expert
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PostPosted: Mon Sep 19, 2011 8:29 pm    Post subject: Reply with quoteFind all posts by expert

Did you try it at all?
Here are some clues
1.)KMnO4+H2SO4+NaHSO3--> MnSO4, S(4+)--> S(6+)

2.)KMnO4+NaOH+NaHSO3--> K2MnO4; S(4+)--> S(6+)

3.)KMnO4+NaHSO3----> MnSO4, S(4+)--> S(6+)

4.) KMnO4 + EDTA + MnSO4(s)----> MnO2; EDTA as an acid

what role did EDTA play in this reaction?
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montinho
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PostPosted: Mon Sep 19, 2011 8:44 pm    Post subject: Reply with quoteFind all posts by montinho

k i have the following, could you please tell me if I am correct?

1) H++2KMnO4(aq)+H2SO4(aq)+5NaHSO3(aq)->2MnSO4(aq)+5K2SO4(aq)+NaSO4(aq)+3H2O

2)
2KMnO4(aq)+3NaOH(aq) + NaHSO3(aq) -> K2SO4 +2K2MnO4(aq) + 2Na2SO4(aq) + 2H2O

3)
2KMnO4 + 3NaHSO3 -> 2MnO2(s)+ K2MnO4 (aq) + 3Na2SO4(aq) + H+ + H2O
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PostPosted: Mon Sep 19, 2011 8:53 pm    Post subject: Reply with quoteFind all posts by expert

1) H++2KMnO4(aq)+H2SO4(aq)+5NaHSO3(aq)->2MnSO4(aq)+5K2SO4(aq)+NaSO4(aq)+3H2O

H+ already comes from H2SO4; NaSO4 incorrect: Na2SO4 correct
2)
2KMnO4(aq)+3NaOH(aq) + NaHSO3(aq) -> K2SO4 +2K2MnO4(aq) + 2Na2SO4(aq) + 2H2O

correct

3)
2KMnO4 + 3NaHSO3 -> 2MnO2(s)+ K2MnO4 (aq) + 3Na2SO4(aq) + H+ + H2O
Incorrect. K2MnO4 forms only at basic conditions. Here you generate acid. Depends on the amount of reagents the outcome is MnO2 or MnSO4 or both
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PostPosted: Mon Sep 19, 2011 8:55 pm    Post subject: Reply with quoteFind all posts by expert

2-nd balanced
http://www.webqc.org/balance.php?reaction=KMnO4%2BH2SO4%2BNaHSO3%3DMnSO4%28aq%29%2BK2SO4%2BNa2SO4%2BH2O
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montinho
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PostPosted: Mon Sep 19, 2011 8:57 pm    Post subject: Reply with quoteFind all posts by montinho

so is 1 like this?

2KMnO4 + H2SO4 + 5NaHSO3 -> 2MnSO4 + 5K2SOR + Na2SO4 + 3H2O

??

and for 3, what should the other products be then? I know in this reaction MnO2 (s) is yielded for sure.
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PostPosted: Mon Sep 19, 2011 9:01 pm    Post subject: Reply with quoteFind all posts by expert

What is K2SOR?

4 KMnO4 + H2SO4 + 10 NaHSO3 = 4 MnSO4(aq) + 2 K2SO4 + 5 Na2SO4 + 6 H2O

That's it!
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Last edited by expert on Mon Sep 19, 2011 9:02 pm; edited 1 time in total
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montinho
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PostPosted: Mon Sep 19, 2011 9:02 pm    Post subject: Reply with quoteFind all posts by montinho

[quote="expert"]What is K2SOR?[/quote]
K2SO4**
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PostPosted: Mon Sep 19, 2011 9:06 pm    Post subject: Reply with quoteFind all posts by expert

Incorrect
Correct is
4 KMnO4 + H2SO4 + 10 NaHSO3 = 4 MnSO4 + 2 K2SO4 + 5 Na2SO4 + 6 H2O

Use this tool if lazy http://www.webqc.org/balance.php
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montinho
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PostPosted: Mon Sep 19, 2011 9:10 pm    Post subject: Reply with quoteFind all posts by montinho

and so what about number 3? i know one of the products is MnO2 (s), i'm sort of lost on this question.
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PostPosted: Mon Sep 19, 2011 9:15 pm    Post subject: Reply with quoteFind all posts by expert

Write the reaction with a single Mn-product MnO2, not MnO2 and MnSO4

If you want MnSO4 then write witha single Mn-product MnSO4

Then if you need both, add one equation to the other.
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montinho
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PostPosted: Mon Sep 19, 2011 9:20 pm    Post subject: Reply with quoteFind all posts by montinho

so is this correct?

2KMnO4 + 3NaHSO3 -> 2MnO2(s) + 3Na2SO4(aq) + H+ + H2O

??
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