Chapter 18, Problem 18.66QP

Interpretation Introduction

Interpretation:

The nickel oxide $(NiO)$ equilibrium pressure $(\text{Kp})$ value should to be derived at ${25}^{°}C$.

Concept Information:

In thermodynamics, free energy (Gibbs free energy) is the term that is used to explain the total energy content in a thermodynamic system that can be converted into work.  The free energy is represented by the letter G.

The equation given below helps us to calculate the change in free energy in a system.

$\text{ΔG = }\Delta {\rm H}\text{- T}\Delta \text{S}$

At a temperature of normal boiling point, the gaseous state of the system will be in equilibrium with the liquid state.  The free energy change in the system will be zero.  Taking the free energy value as zero, molar entropy of vaporization can be calculated using the following equation.

${\text{ΔS}}_{\text{vap}}\text{=}\frac{{\text{ΔΗ}}_{\text{vap}}}{{\text{T}}_{\text{bp}}}$

Where,

${\text{ΔS}}_{\text{vap}}$ is the entropy of vaporization

${\text{ΔΗ}}_{\text{vap}}$ is the enthalpy of vaporization

${\text{T}}_{\text{bp}}$ is the boiling temperature

Free energy$({\text{ΔG}}^0)$: In thermodynamics free energy or Gibbs free energy is the energy that is used to express the total energy content of a system.  According to second law of thermodynamics, in all spontaneous process is associated with the decrease in free energy of the system.  That is the change in free energy will be negative.