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Topic: electronic-ionic method  (Read 5807 times)

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Offline einstein

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electronic-ionic method
« on: July 16, 2011, 04:32:15 PM »
Write the oxidation reaction of Fe(II) to Fe(III) with potassium permanganate in strong acidic environment.
then:
oxidation reaction:Fe2+ =Fe3++e/*5
reduction reaction:MnO4+8H++5e  =Mn2+
+4H2O/*1
what is happening here  ??? how do we now that we need 5 electrons and to take 8 H+
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Offline sjb

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Re: electronic-ionic method
« Reply #1 on: July 17, 2011, 06:43:08 AM »
Quote from: einstein on July 16, 2011, 04:32:15 PM
Write the oxidation reaction of Fe(II) to Fe(III) with potassium permanganate in strong acidic environment.
then:
oxidation reaction:Fe2+ =Fe3++e/*5
reduction reaction:MnO4+8H++5e  =Mn2+
+4H2O/*1
what is happening here  ??? how do we now that we need 5 electrons and to take 8 H+

What is the formula of (potassium) permanganate?
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Offline einstein

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Re: electronic-ionic method
« Reply #2 on: July 17, 2011, 07:53:30 AM »
Formula of potassium permanganate is KMnO4
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Offline sjb

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Re: electronic-ionic method
« Reply #3 on: July 17, 2011, 08:15:37 AM »
Quote from: einstein on July 17, 2011, 07:53:30 AM
Formula of potassium permanganate is KMnO4

So the skeleton half equation for permanangate reduction to manganese(II) is MnO4-  :rarrow: Mn2+. What is there on the left hand side that is not on the right? How do you rectify this?
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Offline einstein

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Re: electronic-ionic method
« Reply #4 on: July 17, 2011, 06:05:44 PM »
MnO-4 = Mn2+
in the left hand are some oxygen atoms more,and yee we take some hydrogen atoms to form water but i can't understand were are going the 5 electrons,how are they distributed,which is taking them ???
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Offline sjb

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Re: electronic-ionic method
« Reply #5 on: July 18, 2011, 02:34:16 AM »
Quote from: einstein on July 17, 2011, 06:05:44 PM
MnO-4 = Mn2+
in the left hand are some oxygen atoms more,and yee we take some hydrogen atoms to form water but i can't understand were are going the 5 electrons,how are they distributed,which is taking them ???

So we have moved on to MnO4- + 8H+  :rarrow: Mn2+ + 4H2O.

What does it mean for an equation to be balanced?
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Offline einstein

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Re: electronic-ionic method
« Reply #6 on: July 18, 2011, 11:25:08 AM »
Do you mean electric balanc or material balanc???
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Offline sjb

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Re: electronic-ionic method
« Reply #7 on: July 18, 2011, 01:22:39 PM »
Quote from: einstein on July 18, 2011, 11:25:08 AM
Do you mean electric balanc or material balanc???

Both materially and electronically
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Offline einstein

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Re: electronic-ionic method
« Reply #8 on: July 19, 2011, 01:34:12 PM »
In fact none of them i don't understand well.
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Offline sjb

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Re: electronic-ionic method
« Reply #9 on: July 19, 2011, 04:24:14 PM »
Quote from: einstein on July 19, 2011, 01:34:12 PM
In fact none of them i don't understand well.

OK, whilst MnO4- + 8H+   :rarrow: Mn2+ + 4H2O is balanced in terms of atoms (1 manganese, 4 oxygens and 8 hydrogens) on both sides, what is the total charge on the left, and on the right?
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Offline einstein

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Re: electronic-ionic method
« Reply #10 on: July 19, 2011, 06:19:19 PM »
total charge on the left is +7,on the right is +2,so when we take 5 electrons,the total charge on the left will be +2,and then this equation is electronically balanced,i think I understood this,thnx
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