Chapter 16, Problem 113QRT

(a)

Interpretation Introduction

Interpretation:

The entropy change for the formation of $\text{1}\text{mol}$ of ${\text{C}}_{\text{2}}{\text{H}}_{\text{2}}\left(\text{g}\right)$ from hydrogen and carbon under standard conditions has to be calculated.

Concept Introduction:

The term entropy is used to represent the randomness in a system.  When a system moves from an ordered arrangement to a less ordered arrangement, then the entropy of the system increases.  The second law of thermodynamics state that “the entropy of the system either increases or remains the same.”

(b)

Interpretation Introduction

Interpretation:

The entropy change for the formation of $\text{1}\text{mol}$ of ${\text{C}}_{\text{2}}{\text{H}}_4\left(\text{g}\right)$ from hydrogen and carbon under standard conditions has to be calculated.

Concept Introduction:

Refer to concept of part (a).

(c)

Interpretation Introduction

Interpretation:

The entropy change for the formation of $\text{1}\text{mol}$ of ${\text{C}}_{\text{2}}{\text{H}}_6\left(\text{g}\right)$ from hydrogen and carbon under standard conditions has to be calculated.  Whether the value of ${\Delta }_{\text{r}}S°$ increases or decreases on adding more number of hydrogen atoms has to be stated.

Concept Introduction:

Refer to concept of part (a).