The standard emf for the cell using the overall cell reaction below is +0.48 V: Zn (s) + Ni²⁺ (aq) → Zn²⁺ (aq) + Ni (s)
The emf generated by the cell when [Ni²⁺] = 2.50 M and [Zn²⁺] = 0.100 M is ________ V.

Question

Quizplus · Accepted Answer

The Nernst equation is:E = E° - (RT/nF)ln(Q)where:E is the cell potential in voltsE° is the standard cell potential in voltsR is the ideal gas constant (8.314 J/mol·K)T is the temperature in Kelvinn is the number of moles of electrons transferred in the balanced chemical equationF is the Faraday constant (96,485 C/mol)Q is the reaction quotientIn this case, the balanced chemical equation is:Zn (s)+ Ni²⁺ (aq)→ Zn²⁺ (aq)+ Ni (s)and n = 2.Substituting the given values into the Nernst equation, we get:E = 0.48 V - (0.0257 V/K)(298 K)/2ln(0.100 M/2.50 M)E = 0.48 V - 0.039 VE = 0.52 VTherefore, the correct answer is C) 0.52 V.

The Standard Emf for the Cell Using the Overall Cell