Chapter 19.6, Problem 19.8CYU

Interpretation Introduction

Interpretation:

The ${\text{Δ}}_{\text{r}}{\text{G}}^{\text{o}}$ for the following reaction has to be determined and find whether it is reactant favoured or product favoured.

  ${\text{H}}_2{\text{(g) + Zn}}^{\text{2+}}\text{(aq) }\to {\text{Zn(s) + 2H}}^{+}\text{(aq)}$

Concept Introduction:

According to the first law of thermodynamics, the change in internal energy of a system is equal ti the heat added to the sysytem minus the work done by the system.

The equation is as follows.

  $\begin{array}{c}\text{ΔU = Q - W}\\ \text{ΔU = Change in internal energy}\\ \text{Q = Heat added to the system}\\ \text{W=Work done by the system}\end{array}$

In voltaic cell, the maximum cell potential is directly related to the free energy difference between the reactants and products in the cell.

  $\begin{array}{c}{\text{ΔG}}^{\text{0}}{\text{= -nFE}}^{\text{0}}\\ \text{n = Number of moles transferred per mole of reactant and products}\\ \text{F = Faradayconstant=96485C/mol}\\ {\text{ E}}^{\text{0}}\text{= Volts = Work(J)/Charge(C)}\end{array}$

The relation between standard cell potential and equilibrium constant is as follows.

  $\text{lnK = }\frac{{\text{nE}}^{\text{0}}}{\text{0}\text{.0257}}\text{ at 298K}$