Urgent A/S Chem: Redox & Oxidation States Watch

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supreme
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Hi I am unsure of this question, as my teacher didn't have time to complete the course before study:

2H20 + SO2 + 2[CuCl4]2- => 4H+ SO42- + 4Cl- + 2[CuCl2]-

Identify the element being reduced in this reaction and write a half equation for the reduction of the species containing this element.
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kriztinae
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(Original post by supreme)
Hi I am unsure of this question, as my teacher didn't have time to complete the course before study:

2H20 + SO2 + 2[CuCl4]2- => 4H+ SO42- + 4Cl- + 2[CuCl2]-

Identify the element being reduced in this reaction and write a half equation for the reduction of the species containing this element.
hmm well i sulpher is being oxidised from +4 to +6
and copper is being reduces from +2 to +1
think thats right. hope it helps
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supreme
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(Original post by kriztinae)
hmm well i sulpher is being oxidised from +4 to +6
and copper is being reduces from +2 to +1
think thats right. hope it helps
Thank you very much :cool: :rolleyes:
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z!D4N
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who has a clear definition of 'oxidation number'?
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kriztinae
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(Original post by supreme)
Thank you very much :cool: :rolleyes:
hehe no problem! :rolleyes:
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z!D4N
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(Original post by z!D4N)
who has a clear definition of 'oxidation number'?
anyone?
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GH
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(Original post by z!D4N)
anyone?
The difference between the number of electrons associated with an element in a compound and the element itself
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z!D4N
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(Original post by 2776)
The difference between the number of electrons associated with an element in a compound and the element itself
thank you!
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Sahir
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(Original post by z!D4N)
who has a clear definition of 'oxidation number'?
For EdExcel we were told "the formal charge assigned to an atom or ion to decide its relative state of oxidation or reduction, assuming all compounds and complex ions are wholly ionic"

For the half equations, by the way.. i got..

SO2 (aq) + 2H2O (l) <---> SO4^2- (aq) + 2e^- + 4H+ (aq)
so sulfur is oxidised from a an ox state of +4 to +6

and

[CuCl4]^2- + e^- <---> [CuCl2]^- + 2Cl^-
so copper is reduced from a state of +2 to +1


I think that's right, yea.. tis. Seeing as they're redox equations, i'm right to use reversible sign thingys, no?!

EDIT: no wait the reduction half equation was wrong.. fixed it now.
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supreme
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Thanks Sahir.

In my revision book it gives the definition of oxidation states as:

  • describes atoms, molecules or ions
  • shows how many electrons have been used in bonding
  • can be appliied to all substances, no matter what the type of bonding
  • is often give the abbreviation Ox (or ON)
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Sahir
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(Original post by supreme)
Thanks Sahir.

In my revision book it gives the definition of oxidation states as:

  • describes atoms, molecules or ions
  • shows how many electrons have been used in bonding
  • can be appliied to all substances, no matter what the type of bonding
  • is often give the abbreviation Ox (or ON)
That'll be useless Letts revision guides then?! Okay it tells you what's going on.. but you can hardly write that in an exam, it's very vague!
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supreme
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Lol but that was Paddy and it is a great book
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Happyelf
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The oxidation number is defined as the sum of negative and positive charges in an atom, which indirectly indicates the number of electrons it has accepted or donated.
or u can have this one if u prefer....
The oxidation number is the charge an atom would carry if the molecule or ion were completely ionic

Lu x
p.s - could someone please look at my other chemistry post please...really need help with that question.
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