[Science Form 3] Compounds

Silicon Compounds

1. Silica
   
   • Components: Silicon, Oxygen.
   • Examples: Sand, Quartz, Flint.
     
     
2. Silicate
   
   • Components: Silicon, Oxygen, Metal.
   • Examples: Mica, Clay, Feldspar, Topaz.
   
   
3. General properties
   
   • Very stable.
   • Insoluble in water.
   • Does not react with acids.
   • Does not discompose on heat.

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Calcium Compounds

Some of the properties of calcium compounds include:

• Insoluble in water.
• Reacts with acids to produce salt, carbon dioxide and water.
• Decomposes on strong heating to produce calcium oxide and carbon dioxide.

Uses of calcium compounds

1. Limestone
   
   • Manufacturer of cement and glass.
   • Extraction of tin and iron.
   • Making quicklime and slaked lime.
     
     
2. Marble
   
   • Making statues and monuments.
   • Cover floors and sides of buildings.
   
   
3. Quicklime
   
   • Neutralise acids in the soil.
   • As a drying agent in the preparation of ammonia gas.
   
   
4. Slaked lime
   
   • Reduce the acidity of soil.
   • Supply calcium to plants.
   • Making caustic soda as a cleaning agent.

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