Question

Be sure to answer all parts.
Calculate E

o

, E, and ΔG for the following cell reactions

(a) Mg(s) + Sn²⁺(aq) ⇌ Mg²⁺(aq) + Sn(s) where [Mg²⁺] = 0.055 M and [Sn²⁺] = 0.050 M

E o = V

E = V

Δ G = kJ

(b) 3Zn(s) + 2Cr³⁺(aq) ⇌ 3Zn²⁺(aq) + 2Cr(s) where [Cr³⁺] = 0.020 M and [Zn²⁺] = 0.0095 M

E o = V

E = V

Δ G = kJ

Answer 1

1) Write the half-reactions and their standard reduction potentials to identify reduction (electron gain) , oxidation (electron loss) and the number of transferred electrons:

,

,

2) Obtain the standard potential of reaction:

3) Obtain the Gibbs free energy:

4) Obtain E with Nern'st equation, (remember that solids are not written in the equilibrium quotient)

b) Second reaction:

1) Write the half-reactions and their standard reduction potentials to identify reduction (electron gain) , oxidation (electron loss) and the number of transferred electrons:

,

,

2) Obtain the standard potential of reaction:

3) Obtain the Gibbs free energy:

4) Obtain E with Nern'st equation, (remember that solids are not written in the equilibrium constant)