Explore BrainMass

Prediction of Changes to DeltaG in Non-Standard Cell

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

-438 kJ/mol is the free energy change of lactate oxidation by Fe3+ under non-standard conditions assuming that:

C3H5O3- + 12 Fe3+ + 3 H2O -----> 3 CO2 + 11 H+ + 12 Fe2+

[Fe2+]=10^-4 M
T=25 degree centigrade
[lactate]=10^-3 M
Carbon dioxide is in equilibrium with atmospheric CO2
Fe3+ is in equilibrium with Fe(OH)3 (s)
Note for Fe(OH)3, Ksp=10^-38
Ksp is the equilibrium constant

Would the following changes make the overall free-energy change more or less favorblae for the overall reaction described above? (Indicate whether the free energy change is sensitive or insensitive to these differences by calculation of free energies):
1. Raise pH of solution to 8.0
2 . Lower Lactate activity to 10^-5 M
3. Add FeCl3 while maintaining solution pH at 7.0
4. Allow CO2 to build up in solution to equilibrate with 10^-2 atm CO2 while maintaining pH at 7.0
5. Raise the solution temperature to 35 degree C. (Describe how this would be done, but please don't solve equations).

© BrainMass Inc. brainmass.com March 21, 2019, 3:17 pm ad1c9bdddf


Solution Summary

The solution shows how to analyze the effect of changing certain conditions on the free energy of a non-standard cell.