Question

1. How will you justify that ice, water, and steam are not different substances but different states of the same substance?
2. Arrange these increasing order of interparticle forces.
3. Which of these stated are regarded as fluids?

Answer 1

a. The given statement can be proved with an activity:

1. Take a piece of about 100-150g of ice in a beaker.
2. Hang a laboratory thermometer in it such that the bulb is in contact with the ice.
3. Start heating the beaker on a low flame.
4. Note down the temperature when the ice starts changing to water.
5. Note the temperature when the whole ice is converted into water.
6. Record the observations for the conversion of solid ice into liquid water.
7. Now, place a glass rod in the beaker and slowly heat the beaker with constant stirring with the help of a glass rod.
8. Note the temperature when water starts changing into water vapor.
9. Keep a close look at the thermometer and note the temperature when most of the water has vaporized.
10. Record the observation for the conversion of water in the liquid state to its vapor state.
11. Observation: One will observe that as temperature increases, the ice start changing into water at $0°\mathrm{C}$, this process is called melting. When the ice has completely melted the water starts changing into a vapor after some time at $100°\mathrm{C}$ or $373\mathrm{K}$, after which it starts boiling.
12. Conclusion: So, we can conclude that ice, water, and steam are the same substance but different states of matter.

b. Increasing order of interparticle forces.

Gases<Liquids<Solids

1. Solid particles are tightly packed and so have the highest interparticle forces.
2. Liquids particles are more loosely packed than solids and so, have lesser interparticle forces.
3. Gas particles are very loosely packed and have the least interparticle forces.

c. Liquid states of matter are also called fluids because the particles of a liquid are loosely packed and they have a tendency to flow.