Chapter 20, Problem 20.20P

(a)

Interpretation Introduction

Interpretation:

For the given reaction process, the sign of $\text{ΔS}$ have to be predicted.

    $C_2{H}_{5}OH\left(g\right)\left(350Kand500torr\right)\stackrel{}{\to }{C}_2{H}_{5}OH\left(g\right)\left(350Kand250torr\right)$

Concept introduction:

Entropy is the measure of randomness in the system.  Standard entropy change in a reaction is the difference in entropy of the products and reactants.  ${\text{(ΔS}}^{\text{°}}{}_{\text{rxn}}\text{)}$ can be calculated by the following equation.

  ${\text{ΔS}}^{\text{°}}{}_{\text{rxn}}{\text{ = S}}^{\text{°}}{}_{\text{Products}}-{\text{ S}}^{\text{°}}{}_{\text{reactants}}$

Where,

  ${\text{S}}^{\text{°}}{}_{\text{reactants}}$ is the standard entropy of the reactants

  ${\text{S}}^{\text{°}}{}_{\text{Products}}$ is the standard entropy of the products

Standard entropy change in a reaction and entropy change in the system are same.

Entropy$\left(S\right)$: 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 $\Delta S<0$

If the disorder equal in a system, then $\Delta S=0$

(b)

Interpretation Introduction

Interpretation:

For the given reaction process, the sign of ${\text{ΔS}}^{\text{o}}$ have to be predicted.

    $N_2\left(g\right)\left(298Kand1atm\right)\stackrel{}{\to }{N}_2\left(aq\right)\left(298Kand1atm\right)$

Concept introduction:

Entropy is the measure of randomness in the system.  Standard entropy change in a reaction is the difference in entropy of the products and reactants.  ${\text{(ΔS}}^{\text{°}}{}_{\text{rxn}}\text{)}$ can be calculated by the following equation.

  ${\text{ΔS}}^{\text{°}}{}_{\text{rxn}}{\text{ = S}}^{\text{°}}{}_{\text{Products}}-{\text{ S}}^{\text{°}}{}_{\text{reactants}}$

Where,

  ${\text{S}}^{\text{°}}{}_{\text{reactants}}$ is the standard entropy of the reactants

  ${\text{S}}^{\text{°}}{}_{\text{Products}}$ is the standard entropy of the products

Standard entropy change in a reaction and entropy change in the system are same.

Entropy$\left(S\right)$: 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 $\Delta S<0$

If the disorder equal in a system, then $\Delta S=0$

(c)

Interpretation Introduction

Interpretation:

For the given reaction process, the sign of ${\text{ΔS}}^{\text{o}}$ have to be predicted.

    $O_2\left(aq\right)\left(303Kand1atm\right)\stackrel{}{\to }{O}_2\left(g\right)\left(303Kand1atm\right)$

Concept introduction:

Entropy is the measure of randomness in the system.  Standard entropy change in a reaction is the difference in entropy of the products and reactants.  ${\text{(ΔS}}^{\text{°}}{}_{\text{rxn}}\text{)}$ can be calculated by the following equation.

  ${\text{ΔS}}^{\text{°}}{}_{\text{rxn}}{\text{ = S}}^{\text{°}}{}_{\text{Products}}-{\text{ S}}^{\text{°}}{}_{\text{reactants}}$

Where,

  ${\text{S}}^{\text{°}}{}_{\text{reactants}}$ is the standard entropy of the reactants

  ${\text{S}}^{\text{°}}{}_{\text{Products}}$ is the standard entropy of the products

Standard entropy change in a reaction and entropy change in the system are same.

Entropy$\left(S\right)$: 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 $\Delta S<0$

If the disorder equal in a system, then $\Delta S=0$