Chapter 2

Question 1

The boundary between two phases is generally described as an…..

Answer 1

interface

Question 2

When one of the phases is a gas or a vapor, the term

Answer 2

surface is frequently used.

Question 3

Surface tension:

Answer 3

It is a property of the surface of a liquid that causes it to behave as an elastic sheet.

It allows insects to walk on water.

It allows small objects, such as needles to float on the surface of water.

It is involved in formation of water droplets on various surfaces or raindrops.

The term Surface tension is typically used when the liquid surface is in contact with gas (air).

Question 4

Cause of surface tension

Answer 4

Surface tension is caused by the attraction between the liquid’s molecules by various intermolecular forces.

Question 5

…….. Is the force per unit length that must be applied ‘parallel’ to the surface so as to counterbalance the net inward pull”.

Answer 5

Surface tension

Question 6

The forces of attraction between water molecules is stronger than those between

Answer 6

alcohol molecules

Question 7

When temperature increase, The intermolecular cohesive forces…….

Answer 7

decrease and the surface tension decrease.

Question 8

By adding surface active agents in water….,

Answer 8

there is a decrease in surface tension of water

Question 9

Surface tension versus interfacial tension

Answer 9

*Surface tension is the tension between liquid-vapor (gas) and solid-vapor.

*Interfacial tension is the tension between 2 immiscible liquids, 2 solids or liquid-solid.

Question 10

Surface tension versus interfacial tension

Answer 10

*Surface tension is the tension between liquid-vapor (gas) and solid-vapor.

*Interfacial tension is the tension between 2 immiscible liquids, 2 solids or liquid-solid.