Thermite

OK. 2 Al(s) + Fe2O3(s) -> Al2O3(s) + 2 Fe(s) releases 850.4 kJ per mole as written and goes forward on its own at 298 K (dG = -838.9 kJ, K = 10^147). Left to keep its own heat it reaches 3139 K, where boiling or melting holds it. Confidence: high. passed element and charge balance, data, adiabatic energy balance, equilibriumreaction enthalpy: -850.4 kJGibbs energy: -838.9 kJequilibrium constant: K = 10^147adiabatic temperature: 3139 K Checks:  [pass] element and charge balance: Al, Fe, O and charge balance exactly  [pass] data: every species comes from NASA Glenn thermodynamic data  [pass] adiabatic energy balance: with the reaction complete and nothing dissociating, the products reach 3139 K (stopped at 3139 K, where a product changes phase and soaks up the rest of the heat). Cantera's full equilibrium did not converge here (its multiphase solver stopped short)  [pass] equilibrium: K is 10^147, so the reaction runs to completion Assumptions:  - The products come from the named reaction 'thermite'.  - Standard states, 1 bar for gases and 1 mol/kg for species in water, with data from NASA Glenn thermodynamic data (JANAF and ATcT based).  - Gases are ideal.  - Thermodynamics says how far and with how much heat a reaction goes, not how fast. A reaction that can go may still need a spark, a catalyst or time. Images: gibbs: images/gibbs.pngReport: report.html

OK. 2 Al(s) + Fe2O3(s) -> Al2O3(s) + 2 Fe(s) releases 850.4 kJ per mole as written and goes forward on its own at 298 K (dG = -838.9 kJ, K = 10^147). Left to keep its own heat it reaches 3139 K, where boiling or melting holds it. Confidence: high. passed element and charge balance, data, adiabatic energy balance, equilibriumreaction enthalpy: -850.4 kJGibbs energy: -838.9 kJequilibrium constant: K = 10^147adiabatic temperature: 3139 K Checks:  [pass] element and charge balance: Al, Fe, O and charge balance exactly  [pass] data: every species comes from NASA Glenn thermodynamic data  [pass] adiabatic energy balance: with the reaction complete and nothing dissociating, the products reach 3139 K (stopped at 3139 K, where a product changes phase and soaks up the rest of the heat). Cantera's full equilibrium did not converge here (its multiphase solver stopped short)  [pass] equilibrium: K is 10^147, so the reaction runs to completion Assumptions:  - Wobbl guessed: temperature not given: assumed 25 C (298.15 K).  - Wobbl guessed: pressure not given: assumed 1 atm.  - The products come from the named reaction 'thermite'.  - Standard states, 1 bar for gases and 1 mol/kg for species in water, with data from NASA Glenn thermodynamic data (JANAF and ATcT based).  - Gases are ideal.  - Thermodynamics says how far and with how much heat a reaction goes, not how fast. A reaction that can go may still need a spark, a catalyst or time. Images: gibbs: images/gibbs.pngReport: report.html