4.4.3 Burning of Magnesium

1.Magnesium before being ignited 2.Magnesium as it ignites
Magnesium before being ignited Magnesium as it ignites
3.Magnesium as it burns 4.Burning residue, magnesium oxide
Magnesium as it burns Burning residue, magnesium oxide

Photo 1:A magnesium ribbon is ignited with the help of a Bunsen burner.
Photo 2:Burning begins. Magnesium reacts with oxygen in a strongly exothermic reaction according to:

2Mg + O2        > 2 MgO
Photo 3:The magnesium burns. Temperatures during burning can go as high as 2400 C. This lead to the magnesium oxide heating up to a white glow. The flame is so bright that objects bathed in magnesium light throw deep shadows even when they're in sunlight.
Photo 4:Reaction product: magnesium oxide.

Raster electron microscope image of magnesium oxide

This reaction was used in the early days of photography in the so-called "lightning powder," which contained magnesium powder and an oxidizing agent, such as calcium chloride (see Experiment 4.4.26).

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