Consider the galvanic cell based on the following half-reactions: Au^3+(aq) + 3 e^-→ Au (s) E° = 1.50 V Tl^+(aq) + e^-→ Tl (s) E° = -0.34 Va) Determine the overall cell reaction and calculate...
Consider the galvanic cell based on the following half-reactions:
Au^3+(aq) + 3 e^-→ Au (s) E° = 1.50 V
Tl^+(aq) + e^-→ Tl (s) E° = -0.34 V
a) Determine the overall cell reaction and calculate E°cell
b) Calculate delta G° and the equilibrium constant K for the cell reaction at 25°C
c) Calculate Ecell at 25°C when [Au3+] = 1.0 x 10^-2M and [Tl+] = 1.0 x 10^-4M. Will the cell potential increase or decrease by increasing the concentration of Au3+?
For parts A & B, see http://www.enotes.com/chemistry/q-and-a/consider-galvanic-cell-based-following-half-333659
Please note that when you post a question, it should only include *one* question. Dividing it into parts A-C does not make it one question :)
For part C, we need to calculate Ecell under non-standard conditions
Ecell = Eocell - 0.0592/n log Q
We know Eocell and have 1.84V (see link above). To find Q, we have to first write the balanced equation
Au3+(aq) + 3Tl(s) --> Au(s) + 3Tl+(aq)
We need the 3s in front of Tl and Tl+ so that the number of electrons in each reaction is the same so that they will cancel out. Now, we can find Q
Q = [Tl+]^3 / [Au3+]
Q = (1x10^-4)^3 / 1x10^-2
Q = 1 x 10^-10
Now we can solve for Ecell
Ecell = 1.84 - (0.0592/3) log (1 x 10^-10)
Ecell = 2.04 V
If we increase the concentration of Au3+, then the value of Q will decrease and the log of the value will also decrease. As a result, the second term will have a greater magnitude so the Ecell will increase because we are substracting a negative term.