Chapter 16, Problem 16.26CP

(a)

Interpretation Introduction

Interpretation:

From the given picture representing initial state 1, initial state 2 and equilibrium state of a reaction, sign of $\Delta H°,\Delta S°$ for the forward reaction has to be ascertained.

Concept Introduction:

• Entropy refers to measurement of randomness or disorderliness in the system.  More the number of molecules in a system more will be the movement of molecules and greater will be the entropy given that weak intermolecular forces prevails between molecules.
• Entropy is denoted by ‘S’ and $\Delta S°$ refers to change in entropy of the system.  $\Delta S°$ value positive for a phenomenon indicates the process is spontaneous.  $\Delta S°$ value negative for a phenomenon indicates the process is non–spontaneous
• The term free energy G, refers to energy available in the system to do work and enthalpy H, refers to heat content of the system.  Change in standard free energy is $\Delta G°$ and change in standard enthalpy is $\Delta H°.$
• All these three parameters are related by an equation,

$\Delta G°=\Delta H°-T\Delta S°$

• Standard free energy change, $\Delta G°,$ is represented as,

$\Delta G°=\Delta H°-T\Delta S°$

       Where,

$\begin{array}{l}\Delta H°=\text{ standard enthalpy change}\\ \Delta \text{S}°\text{= standard entropy change}\end{array}$

• Spontaneous process has – positive entropy value and negative free energy, enthalpy value.
• Non-spontaneous process tends to proceed with negative entropy value and positive free energy and enthalpy.

(b)

Interpretation Introduction

Interpretation:

The difference between the meaning of $\Delta S°$ for the dissociation reaction and $\Delta S$ for the process in which the system goes from initial state 1 to the equilibrium state has to be explained.

(c)

Interpretation Introduction

Interpretation:

Sign of $\Delta G°$ has to be ascertained for the dissociation reaction.  Effect of temperature of $\Delta G°$ has to be described.

Concept Introduction:

• Entropy refers to measurement of randomness or disorderliness in the system.  More the number of molecules in a system more will be the movement of molecules and greater will be the entropy given that weak intermolecular forces prevails between molecules.
• Entropy is denoted by ‘S’ and $\Delta S°$ refers to change in entropy of the system.  $\Delta S°$ value positive for a phenomenon indicates the process is spontaneous.  $\Delta S°$ value negative for a phenomenon indicates the process is non–spontaneous
• The term free energy G, refers to energy available in the system to do work and enthalpy H, refers to heat content of the system.  Change in standard free energy is $\Delta G°$ and change in standard enthalpy is $\Delta H°.$
• All these three parameters are related by an equation,

$\Delta G°=\Delta H°-T\Delta S°$

• Standard free energy change, $\Delta G°,$ is represented as,

$\Delta G°=\Delta H°-T\Delta S°$

Where,

$\begin{array}{l}\Delta H°=\text{ standard enthalpy change}\\ \Delta \text{S}°\text{= standard entropy change}\end{array}$

• Standard free energy change $\Delta G°$ and equilibrium constant of a reaction ‘K’ are related as,

$\Delta G°=-\text{ RT ln K}$

Where,

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

(d)

Interpretation Introduction

Interpretation:

The equilibrium constant whether increase or decrease or remain same if the temperature increases has to be ascertained.  The change in equilibrium state upon increase in temperature has to be described.

(e)

Interpretation Introduction

Interpretation:

Value of $\Delta G$ at equilibrium for the given dissociation reaction has to be evaluated.