magnesium

The white powder is magnesium oxide (MgO).

The equation is :
2Mg(s) + O2(g) → 2MgO(s)

Burning Magnesium
Magnesium is one of the alkaline-earth metals, and is one of the most common elements in the Earth's crust. In its pure form, it is silvery white, and relatively soft. It burns in air with a brilliant white light, and for this reason is often used in flares and fireworks.
2Mg(s) + O2(g) ——> 2MgO(s)
The high temperatures reached during the combustion also allow small amounts of magnesium to react with nitrogen in the air, producing magnesium nitride:
3Mg(s) + N2(g) ——> 2Mg3N2(s)
Magnesium also burns in an environment of carbon dioxide such as in a beaker full of dry ice:
2Mg(s) + CO2(g) ——> 2MgO(s) + C(s)
Magnesium is used in disposable flash bulbs to generate light for photography, but this use has been largely supplanted by other sources of illumination.






IUPAC name
Magnesium oxide

Other names
Magnesia

Properties

Molecular formula
MgO

Molar mass
40.3044 g/mol

Appearance
white powder

Density
3.58 g/cm3

Melting point

3073 K (2800 C)


Boiling point

3873 K (3600 C)


Solubility in water
0.0086 g / 100 mL[1]

Hazards

Main hazards
Metal fume fever; May cause irritation in eyes or respiratory tract

NFPA 704



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1
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Except where noted otherwise, data are given for
materials in their standard state
(at 25 C, 100 kPa)
Infobox disclaimer and references
Magnesium oxide, or magnesia, is

2008-04-03 19:17:28 補充：
The white powder is MgO Magnesium oxide.