Transcript The Thermite Process - South Dakota School of Mines and

The Thermite Process
A very violent reaction that
liberates vast quantities of
heat results in the
formation of molten iron
Purpose

To observe the extremely violent
reaction that leads to the formation
of iron from its oxide (ore)

A regulus is the metallic mass that
forms beneath the slag at the
bottom of a crucible
Demonstration

Reaction is very energetic and
exothermically so

Possibility of explosion if water is
present in the thermite mixture

Temperatures exceed 4500°F
Concepts

Single replacement reactions

Exothermic reactions

Redox reactions
Single Replacement Reactions

General type of inorganic reaction

2Al(s)+Fe2O3(s)
Al2O3(s)+2Fe(l)
Oxide anions are transferred
during reaction from iron(III)oxide to
aluminum
Oxidation number of Fe is 3+ in starting
material and zero in product
Oxidation number of Al is 0 in starting
material and 3+ in product
Oxidation number of oxygen is taken as 2
Exothermic Reactions

Heat flows out of system

Surroundings heat up

Amount of energy liberated equals -730
kJ/mol
where kJ stands for “kilojoules” a unit of
energy, and “mol” stands for the quantity
of matter known as a “mole”
Redox Reactions

“Transfer of electrons” reaction

Redox means “reduction-oxidation”

Al(s) gave its electrons to Fe2O3(s)

Al(s) was oxidized

Fe2O3(s) was reduced
Conclusions

Single replacement reaction defined by
the transfer of oxide anion from Fe2O3 to
Al2O3 in this demonstration

Reaction demonstrates concept of heat
flow

Al(s) gave up electrons so is the reducing
agent

Fe2O3(s) gained electrons so it the
oxidizing agent
Comments

Applications in welding and military
incendiary weapons

Discovered by Hans Goldschmidt
in 1895

Extremely dangerous reaction that
should not be performed by
students
Quiz
1. Who invented the Thermite Process?
2. What is being oxidized in this reaction?
3. What are two applications of this process?
4. What is being reduced in this reaction?
5. Give a definition of an exothermic process.
Answers
1. Hans Goldschmidt
2. Aluminum metal is being oxidized to
aluminum oxide
3. Welding and military incendiary
weapons are a few applications
4. Iron oxide is being reduced to
iron metal
5. Heat flows out of a system and
the surrounding heat up