Consider the following cell at standard conditions: Zn(s) |Zn²⁺(aq) m Fe²⁺(aq) |Fe(s)
Calculate the value of $\Delta$ G_r^$\circ$ for the reaction that occurs when current is drawn from this cell.

Question

Consider the following cell at standard conditions: Zn(s)|Zn²⁺(aq)m Fe²⁺(aq)|Fe(s) Calculate the value of $\Delta$G_r $\circ$ for the reaction that occurs when current is drawn from this cell.

Quizplus · Accepted Answer

To calculate the standard cell potential, we need to look at the oxidation and reduction half-reactions separately:
Oxidation: Zn(s) → Zn2+(aq) + 2e- E° = -0.76V
Reduction: Fe2+(aq) + 2e- → Fe(s) E° = +0.44V

To get the overall reaction, we sum the two half-reactions and cancel the electrons:
Zn(s) + Fe2+(aq) → Zn2+(aq) + Fe(s)

Next, we calculate ΔG° using the following equation:
ΔG° = -nFE°
where n is the number of electrons transferred, F is Faraday's constant (96,485 C/mol e-) and E° is the standard cell potential.

In this case, n = 2, so:
ΔG° = -2 x 96,485 x (0.44 - (-0.76)) = -121,540 J/mol = -121.54 kJ/mol

Finally, we convert ΔG° to ΔG°/mol using the stoichiometry of the balanced equation:
ΔG°/mol = -121.54 kJ/mol ÷ 2 = -60.77 kJ/mol

Therefore, the answer is (A) -62 kJ/mol.

Consider the Following Cell at Standard Conditions: Zn(s)|Zn2+(aq)m Fe2+(aq)|Fe(s) Calculate Δ\DeltaΔ

Consider the Following Cell at Standard Conditions: Zn(s)|Zn²⁺(aq)m Fe²⁺(aq)|Fe(s)
Calculate $\Delta$