(a) Determine the type of cubic lattice to which a given crystal belongs if it has edge length of 290 pm and density is 7.80 g cm–3. (Molecular mass.= 56 g mol–1)
(b) Why does zinc oxide exhibit enhanced electrical conductivity on heating?
we know that
as we have given
d= 7.80 g cm–3.
M=56 g mol–1
a= 290 pm or a3 =2.43 x10-23
putting all value in above equation we get,
hence it belong to bcc crystal lattice.
b) Zinc oxide is white in colour at room temperature. On heating it loses electron and turns yellow in colour.
The electron liberate after heating, can act as charge carrier and thus on heating zinc oxide it exhibit electrical conductivity.