Chapter 18, Problem 18.100SP

(a)

Interpretation Introduction

Interpretation:

Signs of $\Delta H,\Delta G$ and $\Delta S$ have to be determined under the given conditions.

Concept Introduction:

Enthalpy$(\Delta H)$: It is the total amount of heat in a particular system.

$\text{ΔH}$ in a reaction is positive then it is an endothermic reaction whereas the value obtained for $\text{ΔH}$ is negative it is an exothermic reaction.

Free energy change$\left(\Delta G\right)$: Change in the free energy takes place while reactants convert to product.

The free energy $\Delta G$ can be determined by

$\Delta G=\Delta H-T\Delta S$

Where,

$\Delta G$ is the change in free energy

$\Delta H$ is the change in enthalpy

$\Delta S$ is the change in entropy

T is the temperature.

Spontaneous reactions releases the free energy and has $\Delta G<0$ (exergonic)

Nonspontaneous reactions absorbs the free energy and has $\Delta G>0$ (endergonic)

Entropy ($\Delta S$): It is used to describe the disorder. It is the amount of arrangements possible in a system at a particular state.

(b)

Interpretation Introduction

Interpretation:

Structure of rubber band has to be determined from the $\Delta S$ signs under the given conditions.

Concept Introduction:

Entropy ($\Delta S$): It is used to describe the disorder. It is the amount of arrangements possible in a system at a particular state.

If the disorder increases in a system, then $\Delta S>0$

If the disorder decreases in a system, then $\Delta S<0$