Chapter 16, Problem 28QRT

(a)

Interpretation Introduction

Interpretation:

Whether the entropy change is positive or negative for the reaction ${\text{CH}}_{\text{3}}\text{OH}\left(l\right)\to \text{CO}\left(\text{g}\right)+2{\text{H}}_{\text{2}}\left(\text{g}\right)$ has to be predicted.

Concept Introduction:

The entropy of a system is the randomness created by the molecules.  The order of entropy is $\text{gas}>\text{liquid}>\text{solid}$.  Entropy change of a reaction will be positive when the total number of product molecules is greater than the total number of reactants molecules and entropy change will be negative when total reactants molecules are greater than product molecules.

(b)

Interpretation Introduction

Interpretation:

Whether the entropy change is positive or negative for the reaction ${\text{Br}}_2\left(l\right)+{\text{H}}_{\text{2}}\left(\text{g}\right)\to 2\text{HBr}\left(\text{g}\right)$ has to be predicted.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

Whether the entropy change is positive or negative for the reaction ${\text{C}}_{\text{3}}{\text{H}}_{\text{8}}\left(\text{g}\right)\to {\text{C}}_{\text{2}}{\text{H}}_{\text{4}}\left(\text{g}\right)+{\text{CH}}_{\text{4}}\left(\text{g}\right)$ has to be predicted.

Concept Introduction:

Refer to part (a).

(d)

Interpretation Introduction

Interpretation:

Whether the entropy change is positive or negative for the reaction ${\text{Ag}}^{+}\left(\text{aq}\right)+{\text{I}}^{-}\left(\text{aq}\right)\to \text{AgI}\left(\text{s}\right)$ has to be predicted.

Concept Introduction:

Refer to part (a).