Chapter 23, Problem 23.85P

(a)

Interpretation Introduction

Interpretation:

Value of $\Delta G_{rxn}^o$ has to be calculated for the reaction ${\text{NH}}_4\text{Cl}\left(s\right)\underset{}{\overset{}{\rightleftharpoons }}{\text{NH}}_{\text{3}}\left(g\right)\text{+ HCl}\left(g\right)$.

Concept Introduction:

The Gibbs free energy or the free energy change is a thermodynamic quantity represented by $\text{ΔG}$.

Value of $\Delta G_{rxn}^o$ can be calculated by the equation:

  $\Delta G_{rxn}^o\text{= }G°\left[\text{products}\right]-G°\left[\text{reactants}\right]$

(b)

Interpretation Introduction

Interpretation:

Value of equilibrium constant has to be calculated for the reaction ${\text{NH}}_4\text{Cl}\left(s\right)\underset{}{\overset{}{\rightleftharpoons }}{\text{NH}}_{\text{3}}\left(g\right)\text{+ HCl}\left(g\right)$.

Concept Introduction:

Equilibrium constant of a reaction can be determined from the value of $\Delta G_{rxn}^o$ using the given formula,

  ${\text{ΔG}}_{rxn}^o=-\text{RT}\text{ln K}$

(c)

Interpretation Introduction

Interpretation:

Equilibrium partial pressure of $\text{HCl}$ has to be determined.

Concept Introduction:

Ideal gas Equation:

Any gas is described by using four terms namely pressure, volume, temperature and the amount of gas. Thus combining three laws namely Boyle’s, Charles’s Law and Avogadro’s Hypothesis the following equation could be obtained. It is referred as ideal gas equation.

  $\text{PV = nRT}$

Here,

  n is the moles of gas

    P is the Pressure

  V is the Volume

    T is the Temperature

    R is the gas constant

Molar mass can be determined using the given equation,

  $\text{n}\text{= }\frac{\text{m}}{\text{M}}$

Here, n is the number of moles.

  M is the Molar mass.

    m is the Mass