Chapter 16, Problem 16.127CHP

Interpretation Introduction

Interpretation:

$\Delta H°$ and $\Delta S°$ for dissolution of $Pb{I}_2$ has to calculated.

Concept Introduction:

• $\Delta S°$ refers to standard entropy of the reaction which is termed as entropy change in a reaction under standard conditions of $298K$ and $1\text{ atm}$ pressure.  It is represented as,

$\Delta S°=S°\left(products\right)-S°\left(reac\tan ts\right)$

• $\Delta H°$ refers to standard enthalpy change.  Change in enthalpy in a reaction and heat of formation are related by the formula,

$\Delta H_{rxn}^{°}=\Sigma \Delta H_f^{°}(product)-\Sigma \Delta H_f^{°}(reac\tan t)$

Where,

$\begin{array}{l}\Delta H_{rxn}^{°}=\text{ enthalpy change in reaction}\\ \Delta H_f^{°}(product)=\text{ enthalpy or heat of formation of product}\\ \Delta H_f^{°}(reac\tan t)=\text{ enthalpy or heat of formation of }reac\tan t\end{array}$

Standard free energy change of a reaction is related to solubility product of a compound as,

$\Delta G°=-{\text{ RT ln K}}_{sp}$

Where,

$\begin{array}{l}\Delta G°=\text{ standard free energy change}\\ R=\text{ Universal gas constant}\\ \text{T}=\text{ Temperature}\\ {\text{K}}_{sp}\text{= solubility product}\end{array}$