Changes in state of matter

A material will change from one state or phase to another at specific combinations of temperature and surrounding pressure. Typically, the pressure is atmospheric pressure, so temperature is the determining factor to the change in state in those cases.

SUMMARY

• Matter is anything that occupies space and has mass.
• Matter can be classified as solids, liquids and gases on the basis of its physical state.
• Matter is made up of extremely small particles.

• There are spaces between particles of matter.
• The particles of matter are continuously moving.
• The particles of matter attract each other.
• The spaces between particles are minimum in solid state and maximum in gases.
• The kinetic energy of particles minimum in solid state and maximum in gaseous state.
• The force of attraction between particles is maximum in solid state and negligible in gaseous state.
• Liquids and gases exhibit diffusion because their particles possess translatory motion and possess larger interparticle spaces.
• Solid and liquid states are known as condensed states of matter due to smaller interparticle spaces and very little compressibility.
• Liquids and gases are known as fluids because of their ability to flow and take the shape of the container.

EVALUATION

1.Which of the following is not an example of matter?

(a) Air                          (b) Almonds

(c) Cold-drink             (d) Love.

2. Which of the following has the strongest interparticle forces?

(a) Nitrogen                 (b) Water

(c) Iron                        d) Neon.

3 Which of the following has atoms as the constituent particles?

(a) Dry ice                   (b) Argon

(c) Glucose                  (d) Potassium chloride.

Fill in the blanks

Complete the following sentences by supplying appropriate words:

(i) The particles in …… state do not possess translator motion.

(ii) …… and …… states of matter are known as fluid states of matter.

(iii) Particles in …… state possess maximum kinetic energy.

(iv) Kinetic energy of particles of matter …… with increase in temperature.

I .Discussion Question 

5 What are the characteristics of the particles of matter?

6. Which out of iron and chalk has stronger interparticle forces?

7. Give reasons for the following observations:

We can get the smell of perfume sitting from several meters away.

8. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?

9. Describe an activity to demonstrate that the matter consists of particles and that the particles are of extremely small size.

10. What are the characteristics of matter in solid state?

11.P Explain why:

(i) Solids do not undergo diffusion whereas liquids and gases undergo diffusion readily.

(ii) Gases are highly compressible.

12. Give reasons for the following:

(i) A gas fills completely the vessel in which it is kept.

(ii) A gas exerts pressure on the walls of the container.

11. Explain why solid and liquid states are known as condensed states of matter.

14. Give reasons:

(i) Sponge is a solid yet we are able to compress it.

(ii) Sugar when kept in jars of different shapes it takes the shape of the jar yet we call it a solid.

15.With two examples in each case,mention physical and chemical processes in your environment.

16.What are states of matter?Use a suitable diagram to show how one state can be converted to another state.