#
Chemical Thermodynamics

Theory and Applications

## Preview

## Book Description

This book develops the theory of chemical thermodynamics from first principles, demonstrates its relevance across scientific and engineering disciplines, and shows how thermodynamics can be used as a practical tool for understanding natural phenomena and developing and improving technologies and products.

Concepts such as internal energy, enthalpy, entropy, and Gibbs energy are explained using ideas and experiences familiar to students, and realistic examples are given so the usefulness and pervasiveness of thermodynamics becomes apparent. The worked examples illustrate key ideas and demonstrate important types of calculations, and the problems at the end of chapters are designed to reinforce important concepts and show the broad range of applications. Most can be solved using digitized data from open access databases and a spreadsheet. Answers are provided for the numerical problems.

A particular theme of the book is the calculation of the equilibrium composition of systems, both reactive and non-reactive, and this includes the principles of Gibbs energy minimization. The overall approach leads to the intelligent use of thermodynamic software packages but, while these are discussed and their use demonstrated, they are not the focus of the book, the aim being to provide the necessary foundations. Another unique aspect is the inclusion of three applications chapters: heat and energy aspects of processing; the thermodynamics of metal production and recycling; and applications of electrochemistry.

This book is aimed primarily at students of chemistry, chemical engineering, applied science, materials science, and metallurgy, though it will be also useful for students undertaking courses in geology and environmental science.

A solutions manual is available for instructors.

## Table of Contents

**1. An overview of thermodynamics**

What is thermodynamics?

A brief history

The laws of thermodynamics

**2. Fundamental concepts**

Substances and the states of matter; amount of substance

Systems; composition; macroscopic and microscopic properties; concept of equilibrium

Processes

State functions and path functions; the standard state

Energy, work, heat and temperature

Problems

**3. Gases**

Introduction

Gas pressure

Ideal gases; Avogadro’s law and Avogadro’s constant; combined gas law; ideal gas law; gas mixtures

Real gases; the *p−V−T* relationship; compressibility; equations of state for real gases

Problems

4. The first law

The first law; internal energy; mathematical statement of the first law

Enthalpy; the nature of enthalpy; enthalpy of mixing; enthalpy of phase changes

Heat capacity

The enthalpy of substances; variation with temperature; enthalpy increments

Enthalpy of formation

Enthalpy of reaction

Experimental determination of heat capacity and enthalpy

Problems

5. Sources of thermodynamic data for substances

Compilations; the reference state; the NIST−JANAF, NBS and US Geological Survey tables; the FREED software program; Barin’s thermochemical tables

Thermochemical software programs

Problems

6. Some applications of the first law

Heating and cooling of substances

Energy balances

Adiabatic temperature of reaction

Heat utilisation in furnaces

Problems

7. The second and third laws

Entropy and the second law; the nature of entropy; broad implications of the first and second laws; alternative statements of the second law

The entropy of mixing; mixing of ideal gases; the general equation for mixing

The entropy of phase changes

The third law and the entropy of substances

Entropy of formation and entropy of reaction

Entropy as a criterion of sponteneity

Experimental determination of entropy

Problems

8. Gibbs and Helmholtz energy

Combined statement of the 1st and 2nd laws

Helmholtz and Gibbs energy; the criteria for spontaneity; the Gibbs−Helmholtz equation

Gibbs energy of phase changes

Gibbs energy of mixing

Gibbs energy of substances

Gibbs energy of formation

Gibbs energy of reaction

The use of Gibbs energy to study reactions; the importance of kinetics

Experimental determination of Gibbs energy

Problems

9. Solutions

Types of solutions – aqueous, organic, molten and solid solutions

Integral and partial quantities; calculating partial quantities from integral quantities; The Gibbs−Duhem equation

Gas mixtures − ideal and non−ideal gas mixtures

Liquid and solid solutions; the concept of activity; pure substance standard state; infinitely dilute standard state; conversion between standard states; the Gibbs-Duhem equation

Properties of solutions; ideal and non−ideal solutions; excess molar quantities

Experimental measurement of activities

Sources of activity data

Problems

10. Reactive systems – Single reactions

The feasibility of chemical reactions

The equilibrium constant; choice of standard state

The effect of temperature, pressure and concentration on equilibrium

The equilibrium composition of a system; single reactions; multiple reactions within a system

Problems

11. Gibbs energy applications to metal production

Stability of oxides

Reduction reactions; reduction using carbon; reduction with carbon monoxide and hydrogen; reduction using another metal

Oxidation reactions

Metal production strategy

Problems

12. Electrolyte solutions

Aqueous solutions

Enthalpy, Gibbs energy and entropy of ions in solution; sources of thermodynamic data

Activities in electrolyte solutions; the unit activity coefficient approximation; mean ionic activity; activity of the electrolyte; multiple electrolytes in solution

The activity of ions

Partial dissociation; degree of dissociation

The pH scale

Problems

13. Phase equilibria: non−reactive systems

Equilibrium in multi−phase systems; the phase rule

One component systems; an example of a *diagram (carbon)*

Stability of phases; the Clapyron and Clausius−Clapyron equations; the effect of external pressure on vapor pressure

Two−component systems; solid−liquid, solid−solid and liquid−liquid systems Interpreting phase diagrams

Liquid−vapor systems

Thermodynamic basis of phase diagrams

Determination of phase diagrams

Partitioning of components between phases

Further reading

Problems

*14. Phase equilibria: reactive systems*

The phase rule for reactive systems

Phase stability diagrams

The distribution of elements between phases; Examples: solvent extraction and distribution of elements in gas - slag - metal systems

Problems

*15. Complex equilibria*

The stoichiometric approach

Gibbs energy minimization

Commercial software to perform Gibbs energy minimization

Further reading

Problems

*16. Electrochemistry*

Definitions of Ampere, Coulomb and Volt

Electrochemical reactions; example of an electrochemical reaction

Conductors and conduction

Electrochemical cells; contact potential; half−cell and cell reactions; Gibbs energy of cell reactions; electrode potentials; types of electrochemical cells; kinetic effects; total cell potential and Ohmic heating; the laws of electrolysis

Phase stability diagrams

The use of galvanic cells to measure thermodynamic properties

Problems

*17. Some applications of electrochemistry*

Electrolysis − electrowinning of metals; manufacture of chlorine; electrorefining; electroplating; anodizing

Energy required for electrolytic processes

Cementation

Corrosion

Batteries

Fuel cells

*Answers to problems*

## Author(s)

### Biography

**W. John Rankin** has BSc and PhD degrees from the University of Queensland, Australia. He worked initially for MINTEK, then lectured in extractive metallurgy and chemical engineering at the University of Stellenbosh (both in South Africa), the Royal Melbourne Institute of Technology (Australia), and the University of Waterloo (Canada). During the 1990s, he was Professorial Research Fellow and Director of the G.K. Williams Cooperative Research Centre for Extractive Metallurgy at the University of Melbourne. Later, he accepted a position in CSIRO (Australia's national science agency) and held the role of Chief Scientist of the Division of Process Science and Engineering. His research interests are in the fields of thermodynamics, pyrometallurgy, and the implications of sustainability for the minerals industry. He has published over 130 research papers, authored the book *Minerals, Metals and Sustainability: Meeting Future Material Needs* (CRC Press), and edited the third edition of the *Australasian Mining and Metallurgical Operating Practices* (published by the AusIMM). He is co-editor of the journal *Mineral Processing and Extractive Metallurgy*, Adjunct Professor (Swinburne University of Technology, Melbourne), and Honorary Fellow (CSIRO).