Magnesium metal, combustion

For coloured smoke puffs, pigments based on metal chromates are utilised, the pigment being intimately mixed with a fuel such as magnesium. On combustion in free air, a smoke cloud is produced that has residual colour due to the chromate. 

Compounds that contain elements other than carbon also undergo complete combustion to form stable oxides. For instance, sulfur-containing compounds undergo combustion to form sulfur dioxide, S02, a precursor to acid rain. Complete combustion reactions are often also synthesis reactions. Metals, such as magnesium, undergo combustion to form their most stable oxide, as shown in Figure 4.11. 

Magnesium metal burns in oxygen. The smoke and ash that are produced in this combustion reaction are magnesium oxide. 

Although we generally think of combustion reactions as involving oxygen gas, other rapid oxidation reactions are also referred to as combustions. For example, if magnesium metal is placed into chlorine gas, a rapid oxidation takes place, and magnesium chloride is produced. 

T FIGURE 3.6 Combustion of magnesium metal in air, a combination reaction. 

CARBON tetrachloride CCL Tctrachlommethanc Chemically active metals, such as sodium, potassium, magnesium Not combustible ... 

U.2.2-TETRA- CHLORaiJ- DIFLIOROETHANE CCI,F CI,F Refrigerant 112, Halocarbon 112. Freon 112 Chemically active metals sodium, potassium, beryUium, powdered almninum. zinc, magnesium Not combustible ... 

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