Chapter 20, Problem 20.105P

(a)

Interpretation Introduction

Interpretation:

From the given set of graphs, the graph that depict the $G_{sys}$ changes for $HI$ formation has to be identified.

Concept introduction:

Entropy $\text{S}$ : it is used to describe the disorder. It is the amount of arrangements possible in a system at a particular state.

Entropy $\text{S}$ : it is used to describe the disorder. It is the amount of arrangements possible in a system at a particular state. ${\text{ΔS}}_{\text{univ}}={\text{ΔS}}_{\text{sys}}+{\text{ΔS}}_{\text{surr}}$

Any natural process or a chemical reaction taking place in a laboratory can be classified into two categories, spontaneous or nonspontaneous. Spontaneous process occurs by itself, without the influence of external energy. In spontaneous process the free energy of the system decreases and entropy of the system increases.  Nonspontaneous process requires an external influence for initiation.  In nonspontaneous process the free energy of the system increases but entropy of the system decreases.

(b)

Interpretation Introduction

Interpretation:

Which of the given graph depicts the entropy $G_{sys}$ changes as ice melts at $1^{o}C$ and $1atm$ has to be identified.

Concept introduction:

Entropy $\text{S}$ : it is used to describe the disorder. It is the amount of arrangements possible in a system at a particular state.

Entropy $\text{S}$ : it is used to describe the disorder. It is the amount of arrangements possible in a system at a particular state. ${\text{ΔS}}_{\text{univ}}={\text{ΔS}}_{\text{sys}}+{\text{ΔS}}_{\text{surr}}$

Entropy is a thermodynamic quantity, which is the measure of randomness in a system.  The term entropy is useful in explaining the spontaneity of a process.  For all spontaneous process in an isolated system there will be an increase in entropy.  Entropy is represented by the letter ‘S’. It is a state function.  The change in entropy gives information about the magnitude and direction of a process.  The entropy of one mole of substance at a given standard state is called standard molar entropy ($S^o$).