Answer:
ΔGº = --29 kJ
Explanation:
The equation to use is ΔGº = -nFEºcell
where n is the number of mole of electrons exchanged in the redox equation
F is Faraday´s constant 96485 C/mole
Eº cell potential
Ni²⁺(aq) + 2e⁻ ⇒ Ni (s) Eºred = -0.25 V
Cd(s) ⇒ Cd²⁺ + 2e⁻ Eºox = +0.40 V
Eºcell = 0.40 V -0.25 V = 0.15 V
ΔGº = - 2 mole x 96485 C/mol x 0.15 V = -2.9 x 10⁴J = -29 kJ
(remember 1 Coulomb x 1 Volt = 1 Joule)
