Chapter 18, Problem 88A

(a)

Interpretation Introduction

Interpretation: A reaction's entropy increase or decrease is to be determined.

Concept Introduction: Entropy is defined as the measurement of the degree of randomness. The increase in a system's degree of disorder is referred to as an increase in entropy.

Answer to Problem 88A

For the given reaction, the entropy increases.

Explanation of Solution

The give reaction is as follows:

  $\text{C}\left(s\right)+{\text{O}}_2\left(g\right)\to {\text{CO}}_2\left(g\right)$

Only ${\text{CO}}_2$ gas is produced as a result of this reaction, which involves solid carbon and ${\text{O}}_2$ gas reactants. Gases have a greater degree of disorder than solids, which results in a higher entropy for the gaseous state.

Therefore, the entropy increases in the given reaction.

(b)

Interpretation Introduction

Interpretation: A reaction's entropy increase or decrease is to be determined.

Concept Introduction: Entropy is defined as the measurement of the degree of randomness. The increase in a system's degree of disorder is referred to as an increase in entropy.

Answer to Problem 88A

For the given reaction, the entropy increases.

Explanation of Solution

The give reaction is as follows:

  ${\text{Al}}_2{\text{O}}_3\left(s\right)\to 4\text{Al}\left(s\right)+3{\text{O}}_2\left(g\right)$

In this reaction, a solid reactant ${\text{Al}}_2{\text{O}}_3$ produces ${\text{O}}_2$ gas and solid $\text{Al}$ products. Gases have a greater degree of disorder than solids, which results in a higher entropy for the gaseous state.

Therefore, the entropy increases in the given reaction.

(c)

Interpretation Introduction

Interpretation: A reaction's entropy increase or decrease is to be determined.

Concept Introduction: Entropy is defined as the measurement of the degree of randomness. The increase in a system's degree of disorder is referred to as an increase in entropy.

Answer to Problem 88A

For the given reaction, the entropy decreases.

Explanation of Solution

The give reaction is as follows:

  $2\text{N}\left(g\right)\to {\text{N}}_2\left(g\right)$

In this reaction, there is a net production of $1$ mole of ${\text{N}}_2$ gas molecules from $2$ moles of gaseous nitrogen. The decrease in the total number of molecules increases the system's degree of orderliness.

Therefore, the entropy decreases in the given reaction.

(d)

Interpretation Introduction

Interpretation: A reaction's entropy increase or decrease is to be determined.

Concept Introduction: Entropy is defined as the measurement of the degree of randomness. The increase in a system's degree of disorder is referred to as an increase in entropy.

Answer to Problem 88A

For the given reaction, the entropy increases.

Explanation of Solution

The give reaction is as follows:

  ${\text{N}}_2\left(g\right)\to 2\text{N}\left(g\right)$

In this reaction, there is a net production of $2$ moles of gaseous nitrogen from $1$ mole of ${\text{N}}_2$ gas molecules. The increase in the total number of molecules decreases the system's degree of orderliness.

Therefore, the entropy increases in the given reaction.