"Dazzling Flame" experiment
How magnesium burns in the water vapor
This looks like a very simple experiment, but it conceals many interesting chemical processes.
Reagents and equipment:
lighter or matches.
Burn the magnesium strip in the flame of the spirit burner and dip it into the glass of hot water.
Magnesium is an active metal, but its surface is covered with a durable oxide film. On heating this film disintegrates and the magnesium burns with a blinding white flame. The metal burns with the formation of magnesium oxide and nitride. In the water vapor the magnesium burns even more strongly, as magnesium forces the hydrogen out of water, the released hydrogen ignites, and the flame intensifies. Magnesium hydroxide forms, a weak base which turns the water containing phenolphthalein a pink color. Also, the magnesium nitride that is formed in the burning process hydrolyzes, with the formation of magnesium hydroxide and ammonium. When ammonium dissolves in the water containing phenolphthalein it also turns it pink.
2Mg + O₂ → 2MgO
3Mg + N₂ → Mg₃N₂
Mg + H₂O → MgO + Н₂
Mg + 2H₂O → Mg(OH)₂ + Н₂
MgO + H₂O → Mg(OH)₂
Mg₃N₂ + 6H₂O → 3Mg(OH)₂ + 2NH₃
Wear protective gloves and glasses. Use tweezers when lighting the magnesium. You should look at burning magnesium through dark glasses, as there is a risk of receiving a burn to the retina and going blind.
Warning! Substances of this experiment are toxic and highly dangerous for your health. Do not try this at home. Only under professional supervision.