Question

Use standard reduction potentials to calculate the standard free energy change in kJ for the reaction: Ni2 (aq) Cd(s) Ni(s) Cd2 (aq) Answer: -29.529 kJ K for this reaction would be than one.

Answer 1

ΔGº = --29 kJ

Step-by-step 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)