Q53 of 160 Page 20

(a) Define matter. Give four examples of matter.

(b) What are the characteristics of matter?

(a) Matter can be defined as anything that occupies space and has a volume. It possesses mass.

Examples - Air, Water, Soil and plastic.


(b) Characterstics of Particles of Matter


(i) Particles in matter are in a state of continuous motion-


The particles present in matter are not stationary, but have a tendency to acquire motion. In fact they are in a state of continuous motion.


(ii) Particles in matter attract one another-


The particles in matter attract one another. This attraction is inversely proportional to the distance between the particles.


(iii) Particles in matter have spaces between them -


Empty spaces called voids separate the particles from one another. Due to these voids matter is able to disperse into one another bringing about diffusion.


More from this chapter

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51

(a) Compare the properties of solids, liquids and gases in tabular form.

(b) Give two reasons for saying that wood is a solid



During class, the students resemble molecules in a solid (because they are very close to one another)



While going from one classroom to another the students resemble molecules in a liquid (because they are a little more farther apart from one another)



And in the playground students resemble molecules in a gas (because they are very, very far apart from one another)

 52

(a) Why does a gas exert pressure?

(b) Why does a gas fill a vessel completely?


(c) Why are gases so easily compressible whereas it is almost impossible to compress a solid or a liquid?

 54

(a) What is Brownian motion? Draw a diagram to show the movement of a particle (like a pollen grain) during Brownian motion.

(b) In a beam of sunlight entering a room, we can sometimes see dust particles moving in a haphazard way in the air. Why do these dust particles move?

 55

When a crystal of potassium permanganate is placed at the bottom of water in a beaker, the water in the whole beaker turns purple on its own, even without stirring. This is an example of: