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प्रश्न
What makes a glass different from a solid such as quartz? Under what conditions could quartz be converted into glass?
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उत्तर
- Quartz is a hard and crystalline mineral composed of mainly silicon and oxygen atoms. These atoms exist in a continuous link framework of SiO4 tetrahedra.
- Each oxygen is being shared between two units of SiO4.
- Quartz is considered to be the second most abundant mineral in Earth’s crust after feldspar.
- On the other hand, glass is considered to be a non-crystalline and often amorphous solid. It has a widespread practical, technological and decorative use in various fields.
- Glass is often formed by the rapid cooling of the molten form; few glasses, such as volcanic glass, are naturally occurring.
- However, glass on a commercial basis is prepared from silica or silicon dioxide.
- When we compare the two solids, we see that quartz is a crystalline solid with relatively long-range order and glass is an amorphous solid with short-range order and has a tendency to flow.
संबंधित प्रश्न
‘Stability of a crystal is reflected in the magnitude of its melting points.’ Comment. Collect melting points of solid water, ethyl alcohol, diethyl ether and methane from a data book. What can you say about the intermolecular forces between these molecules?
Why does sodium chloride on heating with sodium vapours acquire yellow colour?
Which among the following is not an example of amorphous solids?
Amorphous solids are also known as ____________.
Most crystals show good cleavage because their atoms, ions or molecules are ____________.
Which of the following is not a crystalline solid?
Which of the following statement is not true about amorphous solids?
Why some glass objects from ancient civilisations are found to become milky in appearance?
Which of the following amorphous solid is used as photovoltaic material for conversion of sunlight into electricity?
Which of the following is true about the value of refractive index of quartz glass?
Amorphous solid can also be called:
(i) pseudo solids
(ii) true solids
(iii) supercooled liquids
(iv) supercooled solids
Which of the following features are not shown by quartz glass?
(i) This is a crystalline solid.
(ii) Refractive index is same in all the directions.
(iii) This has definite heat of fusion.
(iv) This is also called super cooled liquid.
The property of crystalline solid is not ______.
Assertion A: Sharp glass edge becomes smooth on heating it upto its melting point.
Reason R: The viscosity of glass decreases on melting.
Choose the most appropriate answer from the options given below.
An ionic solid AB2 isomorphous to the rutile structure (a tetragonal system with the effective number of formula units = 2) has edge lengths of the unit cell of 4Å, 4Å and 7Å. The density of the substance is ______ mg/cc. (if its formula weight is 80. The NA = 6 × 1023 and express your answer in mg/cc using four significant digits.)
