# Electrochemistry - Nernst Equation

• garbagefish
In summary, the Nernst equation was used to calculate the voltage of a voltaic cell at 298 K with non-standard concentrations of 0.08 M [Pb2+] (aq) and 0.5 M [Ag+] (aq). The equation was balanced and the reaction quotient (Q) was calculated, which was then used in the Nernst equation to find the voltage of the cell to be 0.9446V. The same result was obtained using the equation E=Eo-(0.05916/n)logQ.
garbagefish

## Homework Statement

Electrochemistry - Nernst Equation

Pb2+ + 2 e- → Pb (s) ξo = -0.13 V
Ag+ + 1 e- → Ag (s) ξo = 0.80 V

What is the voltage, at 298 K, of this voltaic cell starting with the
following non-standard concentrations:

[Pb2+] (aq) = 0.08 M
[Ag+] (aq) = 0.5 M

## Homework Equations

Use the Nernst equation:

ξ = ξo - (RT/nF) ln Q

## The Attempt at a Solution

there are 2 parts to this question one is to find Q and then use that to
find E.
ξo=0.80-(-0.13)=0.93V

first I balanced the equation:

2(Ag+ + 1 e- → Ag (s))
Pb(s)→ Pb2+ + 2 e-
--------------------
2Ag+ + Pb(s) --> Pb2+ + 2Ag(s)

Q = [products]^p/[reactants]^r
so Q = 0.08/0.5^2 = 0.32

i used ξ = ξo - (RT/nF) ln Q
ξ = 0.93V - ((8.314)(298K)/(2)(96500)) ln0.32 = 0.9446V

I also used E=Eo-(0.05916/n)logQ
E = 0.93V - (0.05916/2)log0.32= 0.9446

I am down to my last try and hoping if anyone can double check this for me. thanks!

Last edited:
How can your answer be negative when the ln of a fraction is a negative, and subtracting a negative number from a positive number should make your answer positive?

o thanks i edited it, i just typed in the - sign for some reason XD, but does the process seem correct?

Yes.

## 1. What is the Nernst Equation and what does it calculate?

The Nernst Equation is an important mathematical relationship in electrochemistry that calculates the equilibrium potential of a cell. It takes into account the concentrations of ions and their respective charges on each side of the cell.

## 2. How is the Nernst Equation used in practical applications?

The Nernst Equation is used in various practical applications, such as in the design and optimization of batteries, fuel cells, and other electrochemical processes. It is also used in analytical chemistry to determine the concentration of ions in a solution.

## 3. What are the factors that can affect the Nernst Equation?

The Nernst Equation is affected by temperature, concentrations of ions, and the number of electrons involved in the redox reaction. Changes in any of these factors can alter the equilibrium potential of the cell.

## 4. How is the Nernst Equation related to the concept of equilibrium in electrochemistry?

The Nernst Equation is directly related to the concept of equilibrium in electrochemistry. It shows the relationship between concentrations of ions and the resulting equilibrium potential of the cell. At equilibrium, the potential difference between the two sides of the cell is zero, and the Nernst Equation reflects this by equalizing the concentrations on both sides.

## 5. What is the difference between the Nernst Equation and the Nernst distribution law?

The Nernst Equation and the Nernst distribution law are two different concepts. The Nernst Equation is used to calculate the equilibrium potential of a cell, while the Nernst distribution law is used to calculate the distribution of ions between two phases at equilibrium. The Nernst distribution law is based on the Nernst Equation but includes additional factors such as temperature and activity coefficients.

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