Advertisements
Advertisements
Question
Under which situations can an amorphous substance change to crystalline form?
Advertisements
Solution
| 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
RELATED QUESTIONS
The relation a ≠ b ≠ c and α ≠ β ≠ γ represents which crystal system?
(A) Orthorhombic
(B) Tetragonal
(C) Triclinic
(D) Monoclinic
Why are solids rigid?
Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show cleavage property?
Define the term ‘amorphous’.
Write any two differences between amorphous solids and crystalline solids
Amorphous solids are also known as ____________.
Most crystals show good cleavage because their atoms, ions or molecules are ____________.
“Crystalline solids are anisotropic in nature″. What is the meaning of anisotropic in the given statement?
A crystalline solid ____________.
Which of the following statements about amorphous solids is incorrect?
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?
Amorphous solids are ______.
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.)
