NCERT Solutions class 9 Science 1. Matter in Our Surroundings Additional -Questions

Que. – What are the characteristics of the particles of matter ?

Ans. - The characteristics of the particles of matter are the following.

1. Particles of matter have space between them.
2. Particles of matter are continuously moving.
3. Particles of matter attract each other.

Que. – Write three physical state of matter.

Ans. -  (i) solid

            (ii) liquid

            (ii) Gas

Que. – What is Evaporation?

Ans. – The phenomenon of change of a liquid into vapours at any temperature below its boiling point is called evaporation.

Que. – Give the reason for the smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close. 

Ans. – It is the property of matter that increasing the temperature, the particles of matter spread very faster. Thus the smell of hot food spread faster than cool food.

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

Ans. – This observation shows that there is space between water molecules (particles of matter).

Que. – What is Fusion?

Ans – The process by which a solid get converted into liquid is known as fusion.

Que. – What is Solidification?

Ane. – The process by which a liquid get converted into solid is known as solidification.

Que. – What is sublimation?

Ane. – The process by which a solid get converted into gas directly without being converted into its liquid form is known as sublimation.

Que. – What is deffusion?

Ans. – Intermixing of particles of two different types of matter on their own is called diffusion.

Que – Write one factor which influence diffusion.

Ans – Heat.

Que. – Why is the rate of diffusion of liquids is higher than that of the solids?

Ans. – This is due to the fact that in the liquid state, particles move freely and have greater space between each other as compared to particles in the solid state.

Que – Write the factors which influence the rate of evaporation.

Ans – There are four factors which influence the rate of evaporation.

1. An increase of surface area.
2. An increase of temperature
3. A decrease in humidity.
4. An increase in wind speed ​

Que – Write the property of solid liquid and gas .

Ans –

Solid:

1. Solid have a definite shape.
2. Solid have a fixed volume.
3. It cannot be changed its shape.
4. Inter molecular force are strongest in solid.

Liquid;

1. Liquids have no fixed shape.
2. Liquids flow and change shape so they are not rigid.
3. They are not compressed.
4. Inter molecular force are less strong in liquids.

Gas:

1. Gases neither have a definite.
2. They can do compressed.
3. Gas can also flow.
4. Inter molecular force are large space than solid and liquid.