Chapter 23, Problem 23.65P

(a)

Interpretation Introduction

Interpretation:

Signs of $\Delta H_{rxn}^o$ and $\Delta S_{rxn}^o$ for the process ${\text{2 C}}_2{H}_2\left(g\right)+5O_2\left(g\right)\underset{}{\to }{\text{4CO}}_2\left(g\right)+2H_{2}O\left(g\right)$ has to be determined.

Concept Introduction:

• Enthalpy$\left(H\right)$: It is the total amount of heat in a particular system.

If the value obtained for $\text{ΔH}$ in a reaction is positive then it is an endothermic reaction whereas the value obtained for $\text{ΔH}$ is negative it is an exothermic reaction.

• 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 $\Delta S<0$

(b)

Interpretation Introduction

Interpretation:

Signs of $\Delta H_{rxn}^o$ and $\Delta S_{rxn}^o$ for the process ${\text{CO}}_2\left(s\right)\underset{}{\to }{\text{CO}}_2\left(g\right)$ has to be determined.

Concept Introduction:

Refer to (a).

(c)

Interpretation Introduction

Interpretation:

Signs of $\Delta H_{rxn}^o$ and $\Delta S_{rxn}^o$ for the when one liter of $He\left(g\right)$ and one liter of $Ar\left(g\right)$ are allowed to mix, forming two liters of gas at constant temperature has to be determined.

Concept Introduction:

Refer to (a).