Zigya Logo

Chapter Chosen

The Solid State

Book Chosen

Chemistry I

Subject Chosen

Chemistry

Book Store

Download books and chapters from book store.
Currently only available for.
CBSE Gujarat Board Haryana Board

Previous Year Papers

Download the PDF Question Papers Free for off line practice and view the Solutions online.
Currently only available for.
Class 10 Class 12
A metallic element exists as a cubic lattice. Each edge of the unit cell is 2.88 A°. The density of the metal is 7.20 g cm–3. How many unit cells will be there in 100 g of the metal?

solution: 
we have given a= 2.88A0
Density = 7.20g cm-3
mass = 100g

Volume of the unit cell = (2.88 A°)3
                          = (2.88×10-8cm)3= 23.9 × 10-24 cm3

Volume of 100g of the metal

                 = WeightDensity=1007.20= 13.9 cm3

No. of unit cell in 13.9 cm3
   
                   = 13.9 cm323.9 × 10-24 cm3= 5.82 × 1023.


Why do solids have a definite volume?

A solid have a definite volume because the inter molecular distance  between its molecules are fixed.

Classify the following as amorphous or crystalline solids: Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.

Amorphous solids: Polyurethane, teflon, cellophane, polyvinyal chloride, fibre glass.
Crystalline solids: naphthlene, benzoic acid, potassium nitrate, copper.

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 clevage property?

Refractive index of a solid which have the same value along all directions are isotropic in nature. It would not show cleavage property.

Why is glass considred a super-cooled liquid?

Glass is amorphous solids and  have a tendency to flow, though very slowly. Therefore, these are called pseudo solids or super cooled liquids .

Why are solids rigid?

Solids are rigid because the internuclear distance between the  molecules of a solid are very less and closely packed and their positions are fixed due to the strong forces of attraction between them.