20. Electrochemistry

Cell Potential and Gibbs Free Energy

Multiple Choice
What is the gibbs free energy change for the given reaction at 25ºC?
Au³⁺ (aq) + 3 Li (s) →. Au (s) + 3 Li⁺ (aq)
Given the following reduction potentials:
Au³⁺(aq) + 3 e^– →. Au(s) E°_red = + 1.50 Volts
Li⁺ (aq) + e^– →. Li (s) E°_red = – 3.04 Volts
Multiple Choice
The reduction of chlorate is given by the equation:
ClO₃^– (aq) + 6 H₃O⁺ (aq) → Cl ^– (aq) + 9 H₂O (l)
If the standard cell potential is given as 1.373 V, how many electrons are transferred under standard conditions?
Multiple Choice
In an electrochemical cell, if the Gibbs free energy change (ΔG) is positive, what can be said about the cell potential (E°cell)?
Multiple Choice
Calculate the maximum obtainable work in kJ for the balanced redox reaction below at 25 °C. Given: 3 MnO4–(aq) + 4 H+(aq) + 5 NO(g) --> 3 Mn2+(aq) + 2 H2O(l) + 5 NO3–(aq), E°cell = 0.540 V. (HINT: 1 V = 1 J/C)
Multiple Choice
Calculate the equilibrium constant (K) for an oxidation-reduction reaction (n = 2) with a cell potential of -0.51 V at 298 K.
Multiple Choice
Given the reaction and standard cell potentials: Ni(s) + 2Ag⁺ (aq) ⇌ Ni²⁺ (aq) + 2Ag(s), where E°_Ag⁺/Ag = +0.80 V and E°_Ni²⁺/Ni = -0.26 V, calculate the standard free energy change (ΔG°) and the equilibrium constant (K) at 25°C for the reaction.
Multiple Choice
What is ΔG° (in kJ/mol) for a redox reaction where two electrons are transferred with E°_cell = -0.273 V?
Multiple Choice
For a large negative E°cell, what values of the equilibrium constant (K) and Gibbs free energy change (ΔG) are expected?
Multiple Choice
What values of the equilibrium constant (K) and Gibbs free energy change (ΔG) are expected for a large positive standard cell potential (E°cell)?