Chapter 3, Problem 3D.2E

a)

Interpretation Introduction

Interpretation:

The standard entropy of the given reaction has to be calculated.

Explanation of Solution

$\begin{array}{l}{\text{2CH}}_{\text{3}}\text{CHO}\text{(g)+}{\text{O}}_{\text{2}}\text{(g)}\underset{}{\to }{\text{2CH}}_{\text{3}}\text{COOH (l)}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(products)}}\text{-}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(reactants)}}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}\left[{\text{S}}^{\text{o}}\left({\text{CH}}_{\text{3}}\text{COOH}\right)\right]\text{-}\left[{\text{S}}^{\text{o}}{\text{(CH}}_{\text{3}}\text{CHO)+}{\text{S}}^{\text{o}}{\text{(O}}_{\text{2}}\text{)}\right]\text{(Q}{\text{ΔS}}^{\text{o}}\text{Values}\text{ referred}\text{from}\text{Appendix-3}\text{)}\\ \\ \text{=}\text{2}\left(\text{159}\text{.8}\text{J/K×mol}\right)\text{-}\left[\text{2}\left(\text{263}\text{.7}\text{J/K×mol}\right)\text{+ }\text{}\text{205}\text{.138}\text{J/K×mol)}\right]\\ \\ \text{=}\text{319}\text{.6}\text{J/K×mol}\text{-}\text{732}\text{.538}\text{J/K×mol}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}\text{-412}\text{.9}\text{J/K×mol}\end{array}$

Therefore, the standard entropy of the given reaction is $-412.9J/K\times mol$

b)

Interpretation Introduction

Interpretation:

The standard entropy of the given reaction has to be calculated.

Explanation of Solution

$\begin{array}{l}\text{2AgCl}{}_{\text{(s)}}\text{+}{\text{Br}}_{\text{2}}{}_{\text{(l)}}\underset{}{\to }\text{2AgBr}{}_{\left(\text{s}\right)}\text{+}{\text{Cl}}_{\text{2}}{}_{\left(\text{g}\right)}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(products)}}\text{-}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(reactants)}}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}\left[{\text{2 S}}^{\text{o}}\left(\text{AgBr}\right){\text{+S}}^{\text{o}}\left({\text{Cl}}_{\text{2}}\right)\right]\text{-}\left[\text{2}{\text{S}}^{\text{o}}\left(\text{AgCl}\right)\text{+}{\text{S}}^{\text{o}}\left({\text{Br}}_{\text{2}}\right)\right]\text{(}{\text{ΔS}}^{\text{o}}\text{Values}\text{ referred}\text{from}\text{Appendix-3}\text{)}\\ \\ \text{=}\left[\text{2}\left(\text{107}\text{.1}\text{J/K}\text{.mol}\right)\text{+}\text{223}\text{.07J/K}\text{.mol}\right]\text{-}\left[\text{2}\left(\text{96}\text{.2}\text{J/K}\text{.mol}\right)\text{+ 152}\text{.23}\text{J/K}\text{.mol)}\right]\\ \\ \text{=}\text{319}\text{.6}\text{J/K}\text{.mol}\text{-}\text{732}\text{.538}\text{J/K}\text{.mol}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}\text{+92}\text{.64 J/K}\text{.mol}\end{array}$

Therefore, the standard entropy of the given reaction is $+92.64J/K.mol$

c)

Interpretation Introduction

Interpretation:

The standard entropy of the given reaction has to be calculated.

Explanation of Solution

$\begin{array}{l}\text{Hg}{}_{\text{(l)}}\text{+}{\text{Cl}}_{\text{2}}{}_{\text{(g)}}\underset{}{\to }{\text{HgCl}}_{\text{2}}{}_{\left(s\right)}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(products)}}\text{-}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(reactants)}}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}\left[{\text{S}}^{\text{o}}\left({\text{HgCl}}_{\text{2}}\right)\right]\text{-}\left[{\text{S}}^{\text{o}}\left(\text{Hg}\right)\text{+}{\text{S}}^{\text{o}}\left({\text{Cl}}_{\text{2}}\right)\right]\text{(}{\text{ΔS}}^{\text{o}}\text{Values}\text{ referred}\text{from}\text{Appendix-3}\text{)}\\ \\ \text{=}\left[\left(146\text{J/K}\text{.mol}\right)\right]\text{-}\left[\left(76.02\text{J/K}\text{.mol}\right)\text{+ }\text{223}\text{.07J/K}\text{.mol}\right]\\ \\ \text{=}\text{146 J/K}\text{.mol}\text{-}\text{299}\text{.09}\text{J/K}\text{.mol}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}-153.09J/K.mol\end{array}$

Therefore, the standard entropy of the given reaction is $-153.09J/K.mol$

d)

Interpretation Introduction

Interpretation:

The standard entropy of the given reaction has to be calculated.

Explanation of Solution

$\begin{array}{l}\text{Zn}{}_{\text{(s)}}\text{+}{\text{Cu}}^{\text{2+}}{}_{\text{(aq)}}\underset{}{\to }{\text{Zn}}^{\text{2+}}{}_{\left(\text{aq}\right)}\text{+}{\text{Cu}}_{\left(\text{s}\right)}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(products)}}\text{-}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(reactants)}}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}\left[{\text{S}}^{\text{o}}\left({\text{Zn}}^{\text{2+}}\right)\text{+}{\text{S}}^{\text{o}}\left(\text{Cu}\right)\right]\text{-}\left[{\text{S}}^{\text{o}}\left(\text{Zn}\right)\text{+}{\text{S}}^{\text{o}}\left({\text{Cu}}^{\text{2+}}\right)\right]\text{(}{\text{ΔS}}^{\text{o}}\text{Values}\text{ referred}\text{from}\text{Appendix-3}\text{)}\\ \\ \text{=}\left[\left(\text{-112}\text{.1J/K}\text{.mol}\right)\text{+}\left(\text{33}\text{.150J/K}\text{.mol}\right)\right]\text{-}\left[\left(\text{41}\text{.63}\text{J/K}\text{.mol}\right)\text{+ }\left(\text{-99}\text{.6J/K}\text{.mol}\right)\right]\\ \\ \text{=}\text{-78}\text{.95 J/K}\text{.mol}\text{+ 57}\text{.97}\text{J/K}\text{.mol}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}\text{-20}\text{.98}\text{J/K}\text{.mol}\end{array}$

Therefore, the standard entropy of the given reaction is $-20.98J/K.mol$

e)

Interpretation Introduction

Interpretation:

The standard entropy of the given reaction has to be calculated.

Explanation of Solution

$\begin{array}{l}{\text{2C}}_{\text{12}}{\text{H}}_{\text{22}}{\text{O}}_{\text{11}}\text{(s) +}\text{12}{\text{O}}_{\text{2}}\text{(g)}\underset{}{\to }{\text{12CO}}_{\text{2}}\text{+}{\text{ 11H}}_{\text{2}}\text{O}\left(\text{l}\right)\\ \\ {\text{ΔS}}^{\text{o}}\text{=}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(products)}}\text{-}{\displaystyle \sum {\text{nS}}^{\text{o}}\text{(reactants)}}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}\left[{\text{12 S}}^{\text{o}}\left({\text{CO}}_{\text{2}}\right)+11{\text{S}}^{\text{o}}\left({\text{H}}_{\text{2}}\text{O}\right)\right]\text{-}\left[{\text{2S}}^{\text{o}}\left({\text{C}}_{\text{12}}{\text{H}}_{\text{22}}{\text{O}}_{\text{11}}\right)\text{+}12{\text{S}}^{\text{o}}{\text{(O}}_{\text{2}}\text{)}\right]\text{(Q}{\text{ΔS}}^{\text{o}}\text{Values}\text{ referred}\text{from}\text{Appendix-3}\text{)}\\ \\ \text{=}\left[\text{12}\left(213.74\right)+11\left(69.91\right)\right]-\left[2\left(360.2\right)+12\left(205.138\right)\right]\text{J/K}\text{.mol}\\ \\ {\text{ΔS}}^{\text{o}}\text{=}+150.9J/K.mol\end{array}$

Therefore, the standard entropy of the given reaction is $+150.9J/K.mol$