NCERT Solutions for Class 9 Science Unit 1

Matter in Our Surroundings Class 9

Unit 1 Matter in Our Surroundings Exercise Solutions

Anything that has both mass and volume is called matter. For example - me, you, chair, table, computer, mouse, keyboard, dog, cat, cow, ram, pen, pencil, tree, plant, building, stone, brick, mountain, river, etc.
Early Indian philosopher categorized matter in five types and called them panch-tatwa (Five-elements) - Vayu (Air), Jal (Water), Agni (Fire), Prithvi (Earth) and Aakash (Sky).
According to science matters are divided according to their physical and chemical properties.
Next Chapter 2 : Is Matter Around Us Pure >>

Question : Solutions of Questions on Page Number : 3

Q1 :  

Which of the following are matter?

Chair, air, love, smell, hate, almonds, thought, cold, cold drink, smell of perfume.


Answer :

Anything that occupies space and has mass is called matter. Matter can exist in three physical states - solid, liquid, and gaseous.

Chair and almond are forms of matter in the solid state.

Cold drink is a liquid state of matter.

Air is a gaseous state of matter.

Note: The sense of smell is not matter. However, the smell or odour of a substance is classified as matter. The smell of any substance (say, perfume) can be classified as matter. This is because, perfume is in liquid state inside the bottle. It comes out in the form of tiny droplets. These droplets of perfume are matter and spread out in the atmosphere to create a sense of smell. This smell can be detected by our olfactory system.

Answer needs Correction? Click Here

Q2 :  

Give reasons for the following observation:

The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close.


Answer :

Solids diffuse at a very slow rate. But, if the temperature of the solid is increased, then the rate of diffusion of the solid particles into air increases. This is due to an increase in the kinetic energy of solid particles. Hence, the smell of hot sizzling food reaches us even at a distance, but to get the smell from cold food we have to go close.

Answer needs Correction? Click Here

Q3 :  

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


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q4 :  

What are the characteristics of particles of matter?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q5 :  

The mass per unit volume of a substance is called density (density = mass/volume). Arrange the following in order of increasing density - air, exhaust from chimney, honey, water, chalk, cotton, and iron.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q6 :  

(a) Tabulate the differences in the characteristics of states of matter.

(b) Comment upon the following: rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy, and density.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q7 :  

Give reasons:

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

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

(c) A wooden table should be called a solid.

(d) We can easily move our hand in air, but to do the same through a solid block of wood, we need a karate expert.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q8 :  

Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. Find out why.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q9 :  

Convert the following temperature to Celsius scale:

(a) 300 K

(b) 573 K


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q10 :  

What is the physical state of water at:

(a) 250°C

(b) 100°C


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q11 :  

For any substance, why does the temperature remain constant during the change of state?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q12 :  

Suggest a method to liquefy atmospheric gases.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q13 :  

Why does a desert cooler cool better on a hot dry day?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q14 :  

How does water kept in an earthen pot (matka)become cool during summers?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q15 :  

Why does our palm feel cold when we put some acetone or petrol or perfume on it?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q16 :  

Why are we able to sip hot tea or milk faster from a saucer than a cup?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q17 :  

What type of clothes should we wear in summers?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Next Chapter 2 : Is Matter Around Us Pure >>

Exercise : Solutions of Questions on Page Number : 12

Q1 :  

Convert the following temperatures to Celsius scale.

(a) 300 K

(b) 573 K


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q2 :  

Convert the following temperatures to Kelvin scale.

(a) 25°C

(b) 373°C


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q3 :  

Give reason for the following observations.

(a) Naphthalene balls disappear with time without leaving any solid.

(b) We can get the smell of perfume sitting several metres away.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q4 :  

Arrange the following substances in increasing order of forces of attraction between particles-- water, sugar, oxygen.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q5 :  

What is the physical state of water at--

(a) 25°C

(b) 0°C

(c) 100°C


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q6 :  

Give two reasons to justify-

(a) water at room temperature is a liquid.

(b) an iron almirah is a solid at room temperature.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q7 :  

Why is ice at 273 K more effective in cooling than water at the same temperature?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q8 :  

What produces more severe burns, boiling water or steam?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q9 :  

Name A, B, C, D, E and F in the following diagram showing change in its state.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Next Chapter 2 : Is Matter Around Us Pure >>

Science : CBSE NCERT Exercise Solutions for Class 9th for Matter in Our Surroundings will be available online in PDF book form soon. The solutions are absolutely Free. Soon you will be able to download the solutions.

Popular Articles