CHAPTER-1
SOLID STATE
ASSIGNMENT
1. For a cubic crystal the face diagonal is 3.50×10-10
m, calculate the face length.(2)
2. In
a face centered unit cell with all the positions occupied by A atoms, the body centered
octahedral hole in it occupied by an atom of B of an appropriate size.
Calculate the void space per unit volume of unit cell for such crystal. Also
predict the formula of compound.(3)
3. A
compound AB has a rock salt type structure .the formula weight of AB is 6.023y amu and the closest A-B distance is y1/3
nm.
(a)Calculate the density of
lattice.
(b)If the observed density of
lattice is found to be 20 kgm-3 then predict the type of
defect.(4)
4. You
are given marbles of diameter 10 mm. They are to be placed such that their
centres are lying in a square bond by four lines each of length 40 mm. what
will be the arrangement of marbles in a plane so that maximum no of marbles can
be placed inside this area. Sketch the diagram and derive expression for the
number of molecules per unit area. .(4)
5. An
element crystallises into a structure which may be described by a cubic type of
unit cell having one atom on each corner of the cube and two atoms on one of
its diagonals. If the volume of unit cell is 24×10-24cm3 and density
of element is 7.2 g cm -3, calculate the number of atoms present in
200 g of element. .(4)
6. Sodium
crystallises in the cubic lattice and the edge of the unit cell is 430 pm.
Calculate the number of atoms in a unit cell. [Atomic mass of Na = 23.0 u,
Density of sodium = 0.9623 g cm-3,
NA= 6.023 x 1023 mol-1] .(4)
7.
The density of solid argon is 1.65 g/ml at -233 °C if the argon atom is assumed
to be sphere of radius 1.54×10-8cm, what percentage of solid argon
is apparently empty space (atomic wt. of Ar is 40 ) .(4)
