Me With An Electrochemical Cell and Equivalence.

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SUMMARY

This discussion centers on two electrochemical problems involving a CuSO4 and ZnSO4 cell and the reactions involving thiosulfate (S2O3{2-}) and hydrogen peroxide (H2O2). The first problem requires calculating the voltage of an electrochemical cell after adding 5 ml of 5M NH4OH to a 0.1M CuSO4 solution, which forms the complex ion Cu(NH3)4{2+}. The second problem involves determining the moles of H2O2 produced or reacted with 1 ml of 0.1N S2O3{2-}. Key concepts include the Nernst equation and the relationship between normality and molarity.

PREREQUISITES
  • Understanding of electrochemical cells and redox reactions
  • Knowledge of complex ion formation and its effect on concentration
  • Familiarity with the Nernst equation for calculating cell voltage
  • Basic concepts of normality and molarity in solution chemistry
NEXT STEPS
  • Study the Nernst equation and its application in electrochemical cells
  • Research the effects of complex ion formation on electrochemical reactions
  • Learn about the stoichiometry of redox reactions involving thiosulfate and hydrogen peroxide
  • Explore the principles of normality and its calculations in solution chemistry
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Chemistry students, electrochemistry enthusiasts, and anyone looking to deepen their understanding of electrochemical cells and redox reactions.

kokoman
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Hi,

Please don't be spooked by the long post, it's just that it contains two problems (I beg your pardon if I shouldn't have put both in one post, I just figured it'll be better than creating two posts...).

I can't figure how to solve these, so if you please could please help me with either one or both... I greatly appreciate any help and will learn from any extent of assistance.

Homework Statement



Problem 1:

An electrochemical cell is given, one containing an 0.1M CuSO4 solution and the other one containing an 0.1M ZnSO4 solution.

Then, the Cu ion concentration is decreased by adding an Ammonia solution NH4OH into the CuSO4 cell, this triggers the following reaction:

Cu{2+} (aq) + 4NH4OH <---> Cu(NH3)4{2+} + 4H2O

{+} denotes charge.

The reaction above decreases the Cu concentration since the complex ion Cu(NH3)4{2+} does not participate in the overall redox reaction of the cell.

Question:

If the volume of each of the solutions (CuSO4, ZnSO4) is 100 cubic centimeters, calculate the Voltage of the cell after 5 ml of 5M NH4OH are added to the CuSO4 cell..?


Problem 2:

The equivalent of Sulfur Tri-oxide S2O3{2-} equals 1 mole of the same.

Given the two reactions:

2H{+} (aq) + 2I{-} (aq) + H2O2 ---> I2 (s) + 2H2O

I2 + 2S2O3{2-} ---> 2I{-} + S4O6{2-}

{-/+} denotes charge.

Question:

Calculate how many moles of H2O2 will be produced from/react with 1 ml 0.1N S2O3{2-} ?

N as in Normality, not M, Molarity.
The reason it says “produced from/react with”, is because the question is translated, and does not explain this exactly in the original form... Please see if you can do anything with that, it will definitely help me learn if I see any progress with this...


Homework Equations





The Attempt at a Solution




Stuck at beginning - not sure how to start, so please help me if you can, or at least kindly point me at the right direction.


Thank you very much!
 
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Do you know the Nernst equation?

The equivalent of Sulfur Tri-oxide S2O3{2-} equals 1 mole of the same.

Thiosulfate, not sulfur trioxide.

If equivalent equals mole, N=M.

And yes, you should post two separate threads. Plus, you should show your efforts.
 

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