Question

Calculate δg o for the reaction between al(s) and cd2+(aq). enter your answer in scientific notation.

Answer 1

The reaction between Al(s) and Cd²⁺(aq) is:
Al(s) + Cd²⁺(aq) → Al³⁺(aq) + Cd(s)

The half reactions are:
Al³⁺(aq) + 3 e⁻ → Al(s)           E⁰ = -1.66 V
Cd²⁺(aq) + 2 e⁻ → Cd(s)        E⁰ = -0.40 V

Reverse the first equation and add to the second one
2 Al(s) + 3 Cd²⁺(aq) → 2 Al³⁺(aq) + 3 Cd(s)

So, the overall cell potential is:
E⁰cell = 1.66 - 0.40 = 1.26 V

Free energy of the reaction is:
ΔG⁰ = -n F E⁰cell
        = - 6 mol e⁻ * (96485 C / mol e⁻) * (1.26 V)
        = - 7.29 x 10⁵ J