Electrochemistry — Practice

Question 1

Calculate E_cell for Zn|Zn2+||Ag+|Ag (E(Zn2+/Zn) = -0.76 V, E(Ag+/Ag) = +0.80 V).

Accepted Answer

E_cell = E_cathode - E_anode = 0.80 - (-0.76) = 1.56 V.

Question 2

Find Lambda° for CH3COOH given lambda°(H+) = 349.8 and lambda°(CH3COO-) = 40.9 S cm^2/mol.

Accepted Answer

Lambda°(CH3COOH) = 349.8 + 40.9 = 390.7 S cm^2/mol.

Question 3

For 2Al + 3Cu2+ -> 2Al3+ + 3Cu, E° = 2.0 V. Calculate delta-G°.

Accepted Answer

n = 6. delta-G° = -nF E° = -6 x 96500 x 2 = -1,158,000 J = -1158 kJ.

Question 4

Find the reduction potential of a Cu electrode in 0.001 M CuSO4 at 25 C (E° = +0.34 V).

Accepted Answer

E = E° + (0.0591/2) log[Cu2+] = 0.34 + 0.02955 x (-3) = 0.34 - 0.0887 = 0.251 V.

Question 5

A 0.05 M KCl solution has conductivity 0.007 S/m at 25 C. Find the molar conductivity.

Accepted Answer

Convert c = 0.05 M = 50 mol/m^3. Lambda_m = kappa/c = 0.007/50 = 1.4e-4 S m^2/mol.

Practice — Electrochemistry