Question

1.2 Why do solids have a definite volume?
1.3 Classify the following as amorphous or crystalline solids: Polyurethane,
naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl
chloride, fibre glass, copper.
1.4 Why is glass considered a super cooled liquid?​

Answer 1

1.2 )Solids have a definite volume and shape because particles in a solid vibrate around fixed locations. Behavior of Solids: Solids have a definite volume and shape because particles in a solid vibrate around fixed locations.

1.4) Glass is called supercooled liquid because glass is an amorphous solid. Amorphous solids have the tendency to flow but, slowly. I doest not form a crystalline solid structure as particles in solids do not move but here it moves. Hence it is called a supercooled liquid.

Answer 2

1.2) Solids have a definite volume because of rigidity in their structure.

• The interparticle forces are very strong.
• The interparticles spaces are very few & small as well.
• As a result, their volumes cannot change by applying pressure.

1.3) Crystalline solids :- Benzoic acid, Potassium nitrate, Copper Amorphous.

Solids :- Polyurethane, Teflon, Cellophane, Polyvinyl chloride, Fibreglass.

1.4) Gass is considered to be super cooled liquid because it shows some of the characteristics of liquids, though it is an amorphous solid.

• Ex :- It is slightly thicker at the bottom.
• This can be possible only if it has flown like liquid though very slowly.

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