Solving a Voitaic Cell: 0.45V Electrochemical Potential

In summary, to determine the concentrations of Ni2+ and Zn2+ when the cell potential falls to 0.45V, the Nernst equation can be used along with the initial concentrations of 1.50M Ni2+ and 0.100M Zn2+. The reaction stoichiometry can also be taken into account to calculate the concentrations after the reaction has occurred. The ratio of 504 can be used to find the concentration of Zn2+ when dividing by 1.50M Ni2+.
  • #1
ahhppull
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Homework Statement


A voitaic cell consists of a Zn/Zn^2+ half-cell and Ni/Ni^2+ half-cell at 25C. The initial concentration of Ni^2+ and Zn^2+ are 1.50M and .100M respectively.

What are the concentrations of Ni2+ and Zn2+ when the cell potential falls to 0.45V?


Homework Equations



Ecell = Ecell(standard) - (0.0592V/n)logK

The Attempt at a Solution



I got the correct answer, but I'm not clear on the method used to solve this problem.

When I used the Nernst equation, I got a ratio of 504 = ([Zn2+]/[Ni2+])

Why would I divide 1.50M Ni2+ by 504 to get the concentration of Zn2+ at 45V?
 
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  • #2
I don't see why dividing the way you described it makes sense. Could be I am missing something, and your description is incomplete, no idea what is what of what.

Concentrations when potential falls to 0.45V can be calculated from initial concentrations and from the reaction stoichiometry. Assume n moles of Zn2+ reacted and write Nernst equation for the system after reaction.
 

1. How does the electrochemical potential of a voltaic cell affect its performance?

The electrochemical potential of a voltaic cell is a measure of the cell's ability to generate electrical energy. A higher electrochemical potential means a greater potential difference between the anode and cathode, resulting in a higher voltage output and better performance of the cell.

2. What is the significance of a 0.45V electrochemical potential in a voltaic cell?

A 0.45V electrochemical potential is considered a moderate potential and is typically seen in common voltaic cells. It indicates a decent amount of energy can be generated, but not necessarily the most efficient or powerful performance.

3. How is the electrochemical potential of a voltaic cell calculated?

The electrochemical potential of a voltaic cell is calculated by subtracting the reduction potential of the cathode from the oxidation potential of the anode. This gives the standard cell potential, which can then be adjusted for temperature and concentration to determine the actual electrochemical potential.

4. Can the electrochemical potential of a voltaic cell be increased?

Yes, the electrochemical potential of a voltaic cell can be increased by using a more reactive anode or a less reactive cathode. This will result in a higher potential difference and therefore a higher electrochemical potential.

5. How does the electrochemical potential relate to the overall efficiency of a voltaic cell?

The electrochemical potential is a key factor in determining the efficiency of a voltaic cell. A higher potential means the cell can produce more electrical energy per unit of reactant, resulting in a more efficient conversion of chemical energy to electrical energy.

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