Intermediate Topic 692 of 1102 Inorganic Chemistry
Thermite Reaction
Aluminium reduces iron oxide in a highly exothermic reaction that produces molten iron.
In-depth explanation of Thermite Reaction
The thermite reaction is a highly exothermic redox reaction in which aluminium powder reduces a metal oxide, most often iron(III) oxide, to molten metal. Aluminium is more reactive than iron, and the formation of very stable aluminium oxide releases so much heat that the iron is produced molten: Fe2O3 + 2Al giving Al2O3 + 2Fe, with an enthalpy change of about -850 kJ. The temperature can exceed 2000 degrees C, enough to weld steel. The mixture needs ignition, usually by a burning magnesium ribbon. Thermite is used to weld railway rails in place.
Going deeper: Thermite Reaction
Key ideas: Fe2O3 + 2Al gives Al2O3 + 2Fe, delta H about -850 kJ per mol, reaching about 2500 C, hot enough for molten iron. Initiated with Mg ribbon and BaO2 igniter because activation energy is high. Used for welding rails and reducing Cr2O3, MnO2 to metals that carbon cannot yield without forming carbides. Aluminium wins because Al-O is strong and Al2O3 lattice energy is large.
Common mistakes and connections: Students think the mixture burns spontaneously; it is stable until ignited. Water cannot be used to put it out. Stoichiometry: 2 mol Al per mol Fe2O3, mass ratio roughly 54 to 160. It is a redox, displacement and exothermic reaction explained via Ellingham diagrams. Links to metallurgy, enthalpy and reactivity series.
Visualization of Thermite Reaction
The thermite reaction Fe2O3 + 2Al has dH near -850 kJ, so Delta G stays strongly negative at all temperatures and produces molten iron. The interactive lesson shows this as a live animation or chart.
Worked example and use case
A mixture of iron(III) oxide and aluminium powder, ignited with magnesium, produces molten iron that can weld rail joints.
Frequently asked questions about Thermite Reaction
What is Thermite Reaction?
Aluminium reduces iron oxide in a highly exothermic reaction that produces molten iron.
Is Thermite Reaction a beginner, intermediate or advanced topic?
Thermite Reaction is a intermediate topic in Inorganic Chemistry. It builds on the vocabulary of beginner topics in this area.
What should I learn before Thermite Reaction?
Study these earlier topics in Inorganic Chemistry first: Roasting and Calcination, Smelting, Ellingham Diagram.
What comes after Thermite Reaction?
The next topics in Inorganic Chemistry are Refining of Metals and Zone Refining.
Can I practise Thermite Reaction with quizzes?
Yes. The interactive lesson includes a self-check question on Thermite Reaction, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Thermite Reaction fits in Inorganic Chemistry
Thermite Reaction is topic 77 of 113 in Inorganic Chemistry.