Answer to Question #317008 in General Chemistry for maya

Question

Calculate the potential of a cell where the Al³⁺ concentration is only 0.10 M. 

2 Al (s) + 3 Cu²⁺ (aq, 1.0 M) → 2 Al³⁺ (aq, 1.0 M) + 3 Cu (s)

Answer 1

2 Al (s) + 3 Cu²⁺ (aq, 1.0 M) → 2 Al³⁺ (aq, 1.0 M) + 3 Cu (s)

Al(s) -3e = Al³⁺(aq), E⁰_ox;

Cu²⁺(aq) +2e = Cu(s), E⁰_red;

E⁰_cell = E⁰_red + E⁰_ox;

E_cell = E⁰_cell + R *T/(n * F) * lg(a²(Al³⁺)/a³(Cu²⁺)).

For T = 25 C = 298 K:

R *T/ F = 0.059

E_cell = E⁰_cell + 0.059/3 * lg(0.1²/1³) = E⁰_cell + 0,020*lg(0.01) = E⁰_cell - 0.04 V.