We have studied that different types of glasses can be prepared by adjusting the chemical composition of the batch material. Different types of glasses are prepared for specific uses. Some of the common uses if glass are as follow:
1. Glass in Construction
- Soda glass is used in making window panes, mirrors and internal glazed partitions.
- Safety type glass, tempered glass and laminated glass are used in buildings.
- Glass-fibre insulations are common in roofs and walls.
2. Glass in Decoration and Fabric.
Coloured glasses and painted glasses are used for manufacturing fancy article, artificial gems, and decorating the fabric.
Household articles are generally made from soft glass. Optical instruments, cut glass objects are made from flint glass or lead crystal glass. Laboratory ware are made of borosilicate glasses.
4. Mirrors and Lenses
Mirrors are generally made from soft glass. Lenses for spectacles, microscopes, telescopes, cameras, etc., are made from crooks’ glass. Sunglasses, however are made from photo-chromatic glasses.
- Glass. Glass is transparent supercooled solid solution of silicates and borates. It is a pseudo solid and non- crystalline in nature. The raw material used for production of glass consists of acidic oxides, basic oxides colouring matter and cullet. It is manufactured by heating the batch material in furnace. The molten glass so obtained is blown into desired article/product and is then subjected annealing followed by finishing.
I. Objective Type Questions
Select the most appropriate choice from the options given as (a), (b), (c) and (d) after each question:
1. The approximate formula of ordinary glass is R2O.MO.6SiO2. In this R can be
2. Which property is not associated with glass?
a) crystalline nature
b) amorphous nature
c) pseudo solid
d) super cooled liquid.
3. Which of the following is not a raw material for ordinary soda glass?
4. The formula of Borax is
5. Addition of Cds to the glass melts imparts …. colour to the glass
6. Which oxide is present in flint glass?
II. Fill in the Blanks
7. Complete the following sentences by supplying appropriate words:
(i) The halogen acid used for etching of glass is …..
(ii) Variety of glass which does not allow u.v rays is …..
(iii) Soft glass is generally made by fusing …..
(iv) Flint glass is generally made of …..
(v) Pyrex glass is kind of …..
III. Discussion Questions
8. What is glass? List some of its common physical characteristics.
9. Name the raw materials for the preparation of glass.
10. Name the basic steps used for the manufacture of glass.
11. Describe the tank furnace for the manufacture of glass. Give various chemical reactions taking place.
12. Explain the following terms.
Hard glass, Soft glass, Pyrex glass, Flint glass
13. Discuss the etching of glass.
I. Objective Type Question
II. Fill in the Blanks
7. (i) HF
(ii) Crooks’ glass
(iii) soda ash, sand and lime stone
(iv) K2CO3, PbO, PbO2, SiO2
(v) borosilicate glass.