Activity 1.7 Class 9 Science

This activity explains how strongly, particles of matter are held in different materials and comparison of strength of intermolecular force between them.

How strong is the intermolecular force between particles of different materials?

Aim of the activity

To compare the strength of intermolecular forces in different solid substances.

Materials used in the activity

1. Iron nail

2. Chalk

3. Rubber band

4. Hammer

5. Cutter or knife

Procedure

We take an iron nail, a piece of chalk and a rubber band. First we try to break the iron nail with hammer and next try to crush the chalk. After try to stretch the rubber band.

Observation

We observe the following

1.  Iron nail cannot be broken with hammer.

2. Chalk is broken easily with hammer.

3. The rubber band can be stretched and finally break when stretched too long.

Explanation

All matters are made up of small particles and these particles have force of attraction between them.

1. In the iron nails, particles are closely and tightly packed with strong force of attraction.

2. In the chalk, particles are less tightly packed so chalk is brittle in nature.

3. Rubber has long chain of molecules and covalent bond is present between these particles so rubber is elastic.

Conclusion

We can conclude that

1.  The iron nails have the strongest force of attraction (intermolecular force) between particles so it is hard to break.

2. The chalk has weak force of attraction between particles so it can be broken easily by applying small external force.

3. The rubber band has moderate force of attraction between particles so it is flexible.

Frequently Asked Questions

1. Which object in this activity is hard to break?

Answer – Iron nail is hard to break.

2. What does this activity explain?

Answer – This activity explains the variation or differences in force of attraction between particles in different solid materials,

3. Why the chalk is brittle in nature?

Answer – Chalk is brittle because there is weak force of attraction between particles.

4. Why does the rubber band show elasticity?

Answer – Rubber band has long flexible chain of polymers that has loosely packed particles.