Thermite reaction

Aluminium is a very reactive metal. Aluminium will reduce iron(III) oxide to iron metal according to the equation below.

2Al(s) + Fe2O3(s) => 2Al2O3(s) + 2Fe(s)
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Mix 20 grams of iron oxide with 6 grams of aluminium powder and place in a small crucible.

Grind a small amount of potassium permanganate into a fine powder. Use just enough KMnO4 to cover the mixture of iron oxide and aluminium powder.

 

Place a few drops of glycerin over the potassium permanganate. The reaction will take a few seconds to start, depending on how fine the KMnO4 is ground. Click to see a 200 kb video of the spontaneous ignition of KMnO4 and glycerin
The energy evolved form this highly exothermic reaction is enough to inititate the highly exothermic reduction of iron(III)oxide to iron metal.

The reaction proceeds with a violent release of heat energy. White hot iron is formed. Click to see a video 1.3 Mb video of the reaction.
The heat given off is enough to melt a metal dish which was used to contain the mixture.
Small balls of iron are formed.

A very visual display of the thermite reaction can be achieved by placing the mixture in a ceramic pot, as shown on the right, with the hole at the bottom taped. When the iron oxide has turned into molten iron it pours out from the bottom.

Click to see the reaction

A very hot mass of iron remains.
Suggest why water should not be used to extinquish a thermite reaction. Click to see a 1 Mb video.
Continue with steel wool.