Saturday, September 24, 2011

Use the Nernst Equation to calculate the cell potential when the concentrations are [Zn^2+] =0.1M and [Cu^2+]=0.001M +1.04v +1.10v +1.16v 0.00v...

For `Zn(s) + Cu^(2+)(aq) -> Zn^(2+)(aq) + Cu(s)` E(st.cell) = +1.10V.


E(st.cell) here is the standard potential. Given the concentrations for the ions of copper and zinc as 0.001M and 0.1M respectively, the Nernst equation can be used to calculate E as follows:


`E = E(st.cell) - ((RT)/(nF))ln(Q)` where n is the number of electrons transferred, and in this case is 2, and Q is the reaction quotient, or the ratio of concentrations of ion products to ion reactants. In this case, Q will be [Zn2+]/[Cu2+] = 0.1/0.001 = 100.


R is the universal gas constant: 8.314 J/molK


F is Faraday's constant: 96, 485 C/mol


T is temperature in kelvin.


No temperature is given, but I will assume that this is STP so that temperature is 25C or 298K.


Then,


`E = +1.10 - ((8.314 * 298)/(2 * 96485))* ln(100) = +1.04V` .


Therefore, the cell potential is +1.04V.


Note that I assumed the temperature to be 298K. If the temperature is different, simply change the temperature, but the entire process remains the same.

No comments:

Post a Comment

What are hearing tests?

Indications and Procedures Hearing tests are done to establish the presence, type, and sever...