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21-Mat-A1 Thermodynamics: Undated paper

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

  1. Question 1 Activity Coefficients from Partial Molar Excess Gibbs Energy Data (Cr–Ni)
  2. Question 2 Combining Two Iron-Oxide Equilibria to get K and ΔG° for the Water–Gas-Shift Reaction
  3. Question 3 Simultaneous Zn–C–O Equilibria — Partial Pressures in a Closed Reactor
  4. Question 4 Temperature Dependence of ΔG° for Cr 3 C 2 Oxidation — Kirchhoff’s Law vs. the Constant-ΔH,ΔS Approximation
  5. Question 5 Oxide/Compound Stability — Reaction Quotient vs. Equilibrium Constant

Start with Question 1 →

National Exams — 12-Mtl-A1, Materials Thermodynamics. Three-hour, closed-book exam; one double-sided aid sheet and an approved (Casio or Sharp) calculator permitted. The cover page states “All FIVE (5) questions need to be answered” — there is no choice among Questions 1–4, and Question 5 offers a straight OR between two alternative problems of equal weight (15%); both are solved below for completeness. Marks: Q1 25%, Q2 15%, Q3 20%, Q4 25%, Q5 15%.

Reference texts: Gaskell, D. R., Introduction to the Thermodynamics of Materials (2nd–5th ed.) — Ch. 6 (Kirchhoff’s law and the temperature dependence of ΔH° and ΔS°), Ch. 9 (partial and integral molar excess free energies, Gibbs–Duhem integration, chemical-equilibrium constants), and Ch. 12–13 (oxide/carbide stability, Ellingham-type ΔG°(T) expressions for extractive metallurgy).