Questions on electrochemical cells using Zn, Cu

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Discussion Overview

The discussion revolves around the electrochemical reactions involving zinc (Zn) and copper (Cu) in electrochemical cells. Participants explore concepts such as electron transfer, oxidation and reduction half-reactions, and the identification of anodes and cathodes. The focus includes both theoretical understanding and practical application related to the balanced chemical equation for the reaction.

Discussion Character

  • Homework-related
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants confirm that there is an electron transfer between species, identifying zinc as the species losing electrons and copper as the species gaining electrons.
  • Participants propose the oxidation half-reaction as Zn → Zn2+ and the reduction half-reaction as Cu2+ → Cu.
  • The anode is identified as zinc and the cathode as copper by some participants.
  • There is a discussion about the direction of the spontaneous reaction, with some stating it occurs from zinc to copper due to the electron flow.
  • One participant expresses uncertainty about the balanced equation, initially stating Zn2+ + Cu → Cu2+ + Zn, and later questioning if it should be Cu2+ + Zn → Cu + Zn2+.
  • Another participant suggests writing the processes of oxidation and reduction separately and combining them to derive the balanced equation.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the balanced equation, with conflicting views on its correct form. There is no consensus on the final balanced equation, and some participants seek clarification on the oxidation and reduction processes.

Contextual Notes

Participants do not fully resolve the mathematical steps involved in deriving the balanced equation, and there are assumptions about the definitions of oxidation and reduction that remain unexamined.

Leesy007
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The problem

http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/animations/CuZncell.html

After veiwing the animation found at the website above answer these questions:

Is there an electron transfer between species?

Which species is losing electrons

Which species is gaining electrons?

Write down the oxidation half reaction under the species that is undergoing oxidation.

Write down the reduction half reaction under the species that is undergoing reduction.

What is the Anode?

What is the Cathode?

Which direction is the spontaneous reaction? Explain your reasoning.

Write the complete balanced equation for the reaction.


2.The attempt at a solution

Is there an electron transfer between species? Yes

Which species is losing electrons? Zinc/Zn

Which species is gaining electrons? Copper/Cu

Write down the oxidation half reaction under the species that is undergoing oxidation. Zn-> Zn 2+

Write down the reduction half reaction under the species that is undergoing reduction. Cu 2+ ->Cu

What is the Anode? Zinc/Zn

What is the Cathode? Copper/Cu

Which direction is the spontaneous reaction? Explain your reasoning.

The spontaneous reaction is occurring from the zinc to the copper because the zinc is losing electrons and the copper is gaining electrons.

Write the complete balanced equation for the reaction.

Zn 2+ + Cu --> Cu 2+ +Zn



Please help me here!

I need someone to check my answers, I'm pretty sure about the first ones, but the last one about the balanced equation I think it wrong.


Any help would be greatly appreciated.


THANKS!
 
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PLEASE please PLEASE HELP!
 
If copper is the species being reduced, how can your reaction be correct?

Zn 2+ + Cu --> Cu 2+ +Zn ?
 
Thats exactly why I need help ! !
 
You will notice that the metallic zinc electrode is being converted to Zn+2 and that the Cu+2 ions in solution are picking up electrons and depositing on the surface of the copper electrode. Write down these two processes one after the other:

A+2 + 2e- ------> A
B -------> B+2 + 2e-
______________________

Add them together and see what you get...
 
A+2 + B ---> B+2 + A

we don't factor in the 2e- because they cancel each other out right?

so it would be:

Zn+2 +2e- ----> Zn
Cu----> Cu+2 + 2e-
___________________
Zn+2 + Cu----> Cu+2 + Zn


Right?
 
wait that's what I had before...

oh god.

would it be

Cu+2 +Zn ----> Cu + Zn+2 ?
 
That's correct. Now examine each of the metals in the equation. Which one is being oxidized and which is being reduced?
 

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