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Sulfur
Sulfur – the element Uses of sulfur Chemical properties of sulfur Sulfur dioxide Acid rain
Sulfuric acid Industrial manufacture of sulfuric acid – the Contact process Uses of sulfuric acid Properties of sulfuric acid Checklist Additional questions
● Sulfur – the element Sulfur is a yellow non-metallic element. It is found in Group VI of the Periodic Table. It is a brittle, non-conducting solid with a fairly low melting point (115 °C). Sulfur will not dissolve in water but will dissolve in solvents such as carbon disulfide and methylbenzene (toluene). Like carbon, sulfur has allotropes. Its main allotropes are called rhombic sulfur and monoclinic sulfur (Figure 12.1).
Sulfur is found in large quantities but in various forms throughout the world. It is found in metal ores such as copper pyrites or chalcopyrite (CuFeS2) and zinc blende (ZnS) and in volcanic regions of the world. Natural gas and oil contain sulfur and its compounds, but the majority of this sulfur is removed as it would cause environmental problems. Sulfur obtained from these sources is known as ‘recovered sulfur’ and it is an important source of the element. It is also found as elemental sulfur in sulfur beds in Poland, Russia and the US (Louisiana). These sulfur beds are typically 200 m below the ground. Sulfur from these beds is extracted using the Frasch process, named after its inventor Hermann Frasch.
Uses of sulfur Sulfur has a very important role in the chemical industry. The vast majority of sulfur is used to produce perhaps the most important industrial chemical, sulfuric acid. Sulfur is also used to vulcanise rubber, a process which makes the rubber harder and increases its elasticity. Relatively small amounts are used in the manufacture of matches, fireworks and fungicides, as a sterilising agent and in medicines.
Chemical properties of sulfur Sulfur will react with both metals and non-metals. ●
It reacts with magnesium metal to form magnesium sulfide. magnesium + sulfur → magnesium sulfide Mg(s) + S(s) → MgS(s)
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It reacts with oxygen to produce sulfur dioxide gas. sulfur + oxygen → sulfur dioxide SO2(g) S(s) + O2(g) →
Figure 12.1 Sulfur – rhombic (top) and monoclinic. 197