Electrochemical Cell Potential Under Non-Standard Conditions

Consider the electrochemical cell:
Pt|Cr2+(0.2752 M), Cr3+(1.705 M)||Co2+(0.2008 M)|Co
a. What is the cell potential (hint: you can solve the problem by half-reactions or by the over-all reaction, both will give you the same answer so you can double check yourself)?
b. Is the cell galvanic or electrolytic (must show math in part (a) to get credit for answer)?

Solution Preview

Please see attached World file as there are equations involved in the calculations that does not show up here.

A. I will do this the over-all reaction way as I feel it is easier:

From the cell notation the anode is Always written on the left side of the double line and the cathode is on the right side.

So Anode is Cr2+/Cr3+ couple. This is where oxidation occurs. Write an oxidation half-reaction where the electrons are on the product side (because oxidation means loss of ...

Solution Summary

This solution contains step-by-step instructions on how to obtain reduction and oxidation half-reactions from the cell notation, how to obtain the cell potential under standard conditions using tabulated tables, and how to correct the cell potential for non-standard conditions using the Nernst equation. Detailed calculations are contained in the attached Word file.

a). Give the cell diagram notation of the electrochemical cell that could be used to determine experimentally the dissociation constant (Kw) of water. The standard reduction potential for
O2 + 2H2O + 4 e-------> 4OH- is + 0.40V
For other half-reactions, use a textbook. Calculate E for this cell.
b). Use yo

It is given that the electrochemicalcell is at 298K. At time zero [Zn 2+ ]= 1.0 x 10 ^-3 M and [Ag +] = 0.500 M. Calculate the molarities of zinc and silver ions after a current of 2.00 amperes flow for 20 hours. Please show step by step and the units you are using.

Part 1. Complete problem 1 from the Problems in electrophysiology 2006 handout. You can find it in the electrophysiology handouts document in the course documents folder. Use the "RT/F ln" form for the GHK equation as was shown in class but multiply RT/F by 1000 to convert volts to millivolts. (Remember that the Nernst equation

Standard potentials are measured against the standard hydrogen electrode (S.H.E.). Because it is not always convenient to use a S.H.E., often other reference electrodes are used. The saturated calomel electrode (S.C.E.) is one commonly used reference electrode, with a potential of 0.242 V versus the S.H.E. Using a table of stand

Two half reactions that join electrically measuring voltage relationship between temp and cell voltage calculating thermodynamic functions.
1. Consider the cell consisting ofthe Fe3+(lM)/ Fe2+and and Br2(latm)/ Br-(lM) redox couples.
a. Write the reduction half-reaction and the corresponding standard reduction potential an

Balance the following redox equations by the ion-electron method:
1) H2O2 + Fe2+ ---> Fe3+ + H2O (in acidic solution)
CN- + MnO4- ---> CNO- + MnO2 (in basic solution)
2) Calculate the standard emf of a cell that uses the Mg/Mg2+ and Cu/Cu2+ half cell reactions at 25 deg C. What is the equation for the cell reaction t

Consider the oxidation of ammonia:
4NH3 (g) + 3O2(g) --> 2N2 (g) + 6H2O
Calcualte the delta G for the reaction. If this reaction were used in a fuel cell, what would the standard cellpotential be? What would be the cellpotential at 100 degrees C?

1. The Standard free energy change for the following reaction is -33.2 kJ/mol and the equilibrium constant Kp=6.59x105 at 25 C.
N2(g) + 3H2 (g) <- -> 2NH3 (g)
In a certain experiment, the initial pressures are P(H2)=0.25 atm, P(N2)= 0.87 atm and P(NH3)=12.9 atm. Calculate Delta G for the reaction at these pressures and pre

1. Using data in Appendix E, calculate the standard emf for each of the following reactions:
(a) H2(g) + F2(g) → 2 H+(aq) + 2 F-(aq)
(b) Cu2+(aq) + Ca(s) → Cu(s) + Ca2+(aq)
(c) 3 Fe2+(aq) → Fe(s) + 2 Fe3+(aq)
(d) 2 ClO3-(aq) + 10 Br-(aq) + 12 H+(aq) → Cl2(g) + 5 Br2(l) + 6 H2O(l)
2. Using the standard reduction po