|Magnesium before being ignited||Magnesium as it ignites|
|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.|
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).