Question

For the effect of concentration experiment, use the experimental standard cell potential, the experimental non- standard cell potential, and the known concentration of zinc of 0.10M to determine the concentration of copper in the solution.

experimental standard cell potential = 1.08V

experimental non standard cell potential = .934

Answer 1

For Zn-Cu cell, the equation is

Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s)

the reaction quotient Q is

Q = [Zn²⁺] / [Cu²⁺]

Applying the Nernst equation,

Ecell = E^∘cell − (0.0591V / n) log Q

Ecell = E^∘cell − (0.0591V / n) log [Zn²⁺]/[Cu²⁺]

Where

Ecell = experimental non standard cell potential = .934

E^∘cell = experimental standard cell potential = 1.08V

n = 2

[Zn²⁺] = 0.1M

Ecell = E^∘cell − (0.0591V / n) log [Zn²⁺]/[Cu²⁺]

0.934 = 1.08 − (0.0591/ 2) log 0.1/[Cu²⁺]

-0.146 = -0.02955 log 0.1/[Cu²⁺]

4.9408 = log 0.1/[Cu²⁺]

87256.94 = 0.1/[Cu²⁺]

[Cu²⁺] = 1.146*10^-6 M