ChemTeach^© - A thermochemical teaching program

ChemTeach is a thermochemical teaching program based on the ChemSage application software. It comprises a disk and a comprehensive workbook. The program illustrates the practical use of thermochemistry for solving everyday problems in industry, research and environmental sciences. Through gaining a knowledge of the practical use of thermochemistry, a student is more inclined to learn the theory behind a rather dry subject matter. The workbook provides the detailed input procedure for the first two of thirteen practical examples; thereafter, only answers to the assignments are shown. The program is interactive and permits a user to check out 'what happens if?' by changing input parameters, and detecting the effects in the results table or diagram output. The workbook also contains a background of the theory relating to the practical application of thermochemistry.

From the ChemTeach workbook:

Foreword

ChemSage TEACH, a combination of a dedicated version of ChemSage and this handbook, is the result of a series of seminars on Computational Thermochemistry held during recent years. Many suggestions of the seminar participants have already been incorporated in both the text and the program. I hope that it helps everybody who uses it to understand that Computational Thermochemistry is a tool for application in day-to-day work but also a method for gaining insight in a sometimes relatively sobering theoretical subject.

Table of Contents

1. Section I - Guided Instruction
   1. Thermodynamic Property Calculations and Preparation of Diagrams

   2. Phase Equilibrium Calculations and Preparation of a Diagram

2. Section II - Practical Assignments
   1. Systems with pure substances
      1. Data for pure substances in SER-form and as relative G-functions: Zn
      2. Production of Ultra-pure Silicon by CVD: Si-H-Cl
      3. Equilibria in the system: C-O-SI
      4. Gas equilibria, substance properties, combustion calculations: C-H-O-N-S
      5. Solid/gas equilibria: Mg-C-O-Si
      6. Thermal decomposition (phase rule): Ca-C-O-Ar

   2. Systems with solution phases
      1. Data for Solution Phases: Pb-Sn
      2. Zero-Phase-Fraction Lines: Co-Cr-Fe, Al-Si-Zn, Fe-C-Cr-W
      3. Phase diagram calculations I: Pb-Sn
      4. Phase diagram calculations II: Mg-Sn
      5. Phase diagram calculations III: Cr-W

   3. Advanced applications
      1. Thermochemistry of an Alloy System: Co-Cr-Fe
      2. Data for mixed phases and pure substances: Al-Cu-Si

   4. Aqueous solutions
      1. Aqueous solutions I: Na-C-Cl-H₂0
      2. Aqueous solutions II: Cu-H₂0

   5. Process thermochemistry
      1. Aluminothermic process: Al-Mo-0
      2. Silicon arc furnace simulation: C-O-Si

3. Section III - Theoretical Background
   1. Equilibria
      1. Stoichiometric reactions
      2. Complex equilibrium calculations
      3. Extensive property balances
   2. Models and data
      1. Gibbs energy data for pure stoichiometric substances
      2. Relative data
      3. Solution phases
   3. Phase diagrams
      1. Types of phase diagrams
      2. Zero phase fraction lines
      3. Phase rule
   4. Summary
   5. Process simulation
      1. Steady-state calculations for dynamic processes

Introduction

This text shall help the user to practice the three step process which is always involved in the application of computational thermochemistry:

1. Analysis of the practical problem in terms of input for a calculation,
2. execution of the calculation
3. interpretation of the results in relation to the initial practical problem.

In order to execute this three step process properly the handbook provides on the one hand information on the actual use of the calculation modules of ChemSage (section I) and on the other an outline of the theoretical background of computational thermochemistry (section III). The practical assignments (section II) are embedded in these two sections. The appropriate cross-references to sections I and III are given with each assignment in section II.

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