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GLASS
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GLASS
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| Glass is an inorganic super cooled liquid. It has no definite melting point. It has very high viscosity which prevents its crystallization. Generally glass are the silicates of sodium and calcium. | |||
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FORMATION
OF GLASS
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| Glasses are formed by allowing molten silicates to cool. | |||
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TYPES
OF GLASS
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ORDINARY WINDOW GLASS (SODA GLASS)
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| Preparation: | |||
| It is prepared by heating a mixture of silica (SiO2), Na2CO3 and CaCO3 in a furnace. | |||
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Na2CO3
+ SiO2 è
Na2SiO3
+ CO2
CaCO3 + SiO2 è CaSiO3 + CO2 |
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| Properties: | |||
| It
is not a very expensive kind of glass. It is easy to work . It breaks and get scratched easily. For latest information , free computer courses and high impact notes visit : www.citycollegiate.com |
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| Uses : | |||
| Bottles, windows,flat glass sheet. | |||
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BOROSILICATE
OR PYREX GLASS |
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| Preparation: | |||
| It is prepared from silica, Boron oxide (B2O3),Aluminum oxide (Al2O3) and sodium oxide (Na2O). | |||
| Properties: | |||
| It has high softening temperature. It bears high temperature. | |||
| Uses : | |||
| Laboratory wares such as beakers, test tube, flask etc. | |||
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CRYSTAL
GLASS
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| Preparation: | |||
| It is prepared by silica, lead oxide (PbO) potassium carbonate (K2CO3) and CaCO3. | |||
| Properties: | |||
| It is heavy glass. It is very expensive. | |||
| Uses : | |||
| In decorative glass show piece. | |||
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COLOURED
GLASS
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| Preparation:
For latest information , free computer courses and high impact notes visit : www.citycollegiate.com |
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| It
is prepared by mixing different chemical compound in molten glass. These
compound give a particular colour to glass. e.g: red colour :Cu2O and AuCl3 Blue : CuO Green :Cr2O3 |
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WATER
GLASS
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| Na2SiO3 is commonly known as water glass. | |||
| Preparation: | |||
| It is prepared by heating sodium carbonate with silica. | |||
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Na2CO3
+ SiO2 è
Na2SiO3 + CO2
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| Uses : | |||
| It is used in the manufacture of fire proofing material. | |||
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SILICA
GEL
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| When an acid is added to a solution of water glass, it turns into a jelly like substance known as Gel (SiO2.H2O) on heating the Gel dehydrates and forms a hard porous material which is known silica Gel. It is a good moisture absorbent and is used in medicine packing to absorb moisture. | |||
| For latest information , free computer courses and high impact notes visit : www.citycollegiate.com | |||