21-Mat-A1 Thermodynamics
Worked solutions to 7 past sittings (2014–2018), 47 questions. Pick a sitting, or start from a topic below.
Topics across the sittings
Topics that come up in more than one sitting, taken from the headings of our worked solutions. A topic counts once per sitting.
- Reading the Ellingham Diagram (3 sittings): December 2015 Q7 · May 2015 Q7 · May 2014 Q7
- Adiabatic Flame Temperature of Acetylene (2 sittings): December 2015 Q4 · May 2015 Q4
- Entropy (2 sittings): December 2017 Q2 · December 2015 Q3
- Entropy of Reversible (2 sittings): May 2017 Q2 · May 2014 Q3
- Equilibrium Constant (2 sittings): May 2014 Q5 · Undated paper Q5
- Irreversible Isothermal Compression (2 sittings): May 2017 Q2 · May 2014 Q3
- Potential (2 sittings): December 2018 Q6 · December 2017 Q6
- Reversible Adiabatic Ideal-Gas Process (2 sittings): December 2015 Q2 · May 2015 Q2
- Ti/TiO₂ Equilibria (2 sittings): May 2015 Q7 · May 2014 Q7
Questions by sitting
December 2018
- Question 1: First-Law Bookkeeping Around a Rectangular P–V Path from A to D
- Question 2: Entropy of Reaction for CO Oxidation at 500 K
- Question 3: $C_v$ and $C_p$ Are Independent of Volume and Pressure for an Ideal Gas
- Question 4: Dissociation Equilibrium Compositions in Two Gas Tanks
- Question 5: Heats of Combustion of Four Hydrocarbon Fuels
- Question 6: Zn/Fe 2+ Galvanic Cell — Potential, Free Energy, K and Concentration Dependence
- Question 7: Ellingham-Diagram Readings for Mn/MnO and Ca
December 2017
- Question 1: First-Law Bookkeeping Around a Rectangular T–V Cycle
- Question 2: Entropy and Enthalpy of Lead Through Its Melting Point
- Question 3: Reversible Adiabatic Expansion of an Ideal Gas
- Question 4: Adiabatic Flame Temperature of Acetylene Combustion
- Question 5: Water–Gas Shift Equilibrium Composition at Two Temperatures
- Question 6: Galvanic Cell — Sn/Pb Concentration and Potential
- Question 7: Ellingham-Diagram Equilibria for Ti, Ca and Si Oxides at 1600°C
May 2017
- Question 1: First-Law Bookkeeping Around a Rectangular P–V Cycle
- Question 2: Entropy of Reversible vs. Irreversible Isothermal Compression
- Question 3: Reaction Entropy of Ammonia Synthesis at 700 K
- Question 4: Thermodynamics of Sulfuric Acid Formation from Elemental Sulfur
- Question 5: Heats of Combustion and Gravimetric Energy Density of Four Fuels
- Question 6: Galvanic Cell Thermodynamics for Ba/Cu 2+
- Question 7: Ellingham-Diagram Equilibria for Si/SiO₂ and the Ti–SiO₂ Reduction
December 2015
- Question 1: First-Law Bookkeeping for a Monatomic Ideal Gas — Two Paths, Same Endpoints
- Question 2: The Reversible Adiabatic (Isentropic) Ideal-Gas Process
- Question 3: Entropy and Enthalpy of Heating Through Two Phase Transitions
- Question 4: Adiabatic Flame Temperature of Acetylene — Pure Oxygen vs. Air
- Question 5: Heats of Combustion of Four Fuels, Per Mole and Per Unit Mass
- Question 6: Galvanic Cell Thermodynamics — Zn/Cu²⁺ and the Nernst Equation
- Question 7: Reading the Ellingham Diagram — Al/Al₂O₃ Equilibria and the Ca–MgO Reduction
May 2015
- Question 1: First-Law Bookkeeping for a Monatomic Ideal Gas — Isobaric–Isochoric–Isothermal Cycle
- Question 2: The Reversible Adiabatic (Isentropic) Ideal-Gas Process
- Question 3: Temperature Dependence of ΔS° — CO Oxidation at 500 K
- Question 4: Adiabatic Flame Temperature of Acetylene — Oxygen vs. Air
- Question 5: Gibbs Energy of Mixing Ideal Gases
- Question 6: Gas-Phase Dissociation Equilibria — O₂⇌2O and H₂+½O₂⇌H₂O
- Question 7: Reading the Ellingham Diagram — Cu/Cu₂O, Cr/Cr₂O₃ and Ti/TiO₂ Equilibria
May 2014
- Question 1: First-Law Bookkeeping for an Ideal Gas — Irreversible Expansion Then Isochoric Cooling
- Question 2: Cv and Cp Are Independent of Volume and Pressure at Constant T
- Question 3: Entropy of Reversible vs. Irreversible Isothermal Compression
- Question 4: Heats of Combustion from Standard Enthalpies of Formation
- Question 5: Equilibrium Constant and Reaction Thermodynamics for NO₂ Dissociation
- Question 6: Gibbs Energy of Mixing of Ideal Gases
- Question 7: Reading the Ellingham Diagram — Ti/TiO₂ Equilibria
Undated paper
- Question 1: Activity Coefficients from Partial Molar Excess Gibbs Energy Data (Cr–Ni)
- Question 2: Combining Two Iron-Oxide Equilibria to get K and ΔG° for the Water–Gas-Shift Reaction
- Question 3: Simultaneous Zn–C–O Equilibria — Partial Pressures in a Closed Reactor
- Question 4: Temperature Dependence of ΔG° for Cr 3 C 2 Oxidation — Kirchhoff’s Law vs. the Constant-ΔH,ΔS Approximation
- Question 5: Oxide/Compound Stability — Reaction Quotient vs. Equilibrium Constant