Advertisements
Advertisements
प्रश्न
Under which situations can an amorphous substance change to crystalline form?
Advertisements
उत्तर
| Property | Crystalline solids | Amorphous solids |
| Shape Melting point | Definite characteristic geometrical shape Melt at a sharp and characteristic temperature | Irregular shape Gradually soften over a range of temperature |
| Cleavage property | When cut with a sharp edged tool. they split into two pieces and the newly generated surfaces are plain and smooth | When cut with a sharp edged tool. they cut into two pieces with irregular surfaces |
| Heat of fusion | They have a definite and characteristic enthalpy of fusion | They do not have definite enthalpy of fusion |
| Anisotropy Nature Order in arrangement of constituent particles | Anisotropic in nature True solids Long range order |
Isotropic in nature Pseudo solids or super cooled liquids Only short range order |
APPEARS IN
संबंधित प्रश्न
The relation a ≠ b ≠ c and α ≠ β ≠ γ represents which crystal system?
(A) Orthorhombic
(B) Tetragonal
(C) Triclinic
(D) Monoclinic
Why do solids have a definite volume?
Classify the following as amorphous or crystalline solids:
Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.
Why is glass considered a super cooled liquid?
Define the term ‘amorphous’.
What makes a glass different from a solid such as quartz? Under what conditions could quartz be converted into glass?
Write any two differences between amorphous solids and crystalline solids
Why does sodium chloride on heating with sodium vapours acquire yellow colour?
Assertion: Stability of a crystal is reflected in the magnitude of its melting.
Reason: The stability of a crystal depends upon the strength of the interparticle attractive force.
Most crystals show good cleavage because their atoms, ions or molecules are ____________.
A crystalline solid ____________.
Which of the following is an amorphous solid?
The sharp melting point of crystalline solids is due to ______.
Why some glass objects from ancient civilisations are found to become milky in appearance?
Amorphous solids are ______.
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.
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.
