NCERT Solutions for Class 9 Science Chapter 1 Matter in Our Surroundings

 

NCERT solutions for class 9 science chapter 1 Matter in Our Surroundings: If you are looking for solutions for NCERT class 9 science chapter 1 Matter in Our Surroundings then you are at the right place. This article contains step by step solutions to each question. The detailed NCERT solutions to all the exercise questions provided here will help you to understand the fundamental concepts involved in chapter 1 Matter in our Surroundings. As we know the matter is made up of particles and as we look at our surroundings, we see a large variety of things with different shapes, sizes, and texture. Through CBSE NCERT solutions for class 9 science chapter 1 Matter in Our Surroundings, you will be able to understand the questions and its concepts related to some important topics of this chapter.

Here are important topics of chapter 1 Matter in Our Surroundings:

1.1 Physical Nature of Matter

1.1.1 Matter Is Made up of Particles

1.1.2 How Small Are These Particles of Matter?

1.2 Characteristics of Particles of Matter

1.2.1 Particles of Matter Have Space Between Them

1.2.2 Particles of Matter Are Continuously Moving

1.2.3 Particles of Matter Attract Each Other

1.3 States of Matter

1.3.1 the Solid State

1.3.2 the Liquid State

1.3.3 the Gaseous State

1.4 Can Matter Change Its State?

1.4.1 Effect of Change of Temperature

1.4.2 Effect of Change of Pressure

1.5 Evaporation

1.5.1 Factors Affecting Evaporation

1.5.2 How Does Evaporation Cause Cooling?

NCERT solutions for class 9 science chapter 1 Matter in Our Surroundings

Topic 1.2 Characteristics of particles of matter

Q 1.   Which of the following is matter?

Chair, air, love, smell, hate, almonds, thought, cold, lemon water, the smell of perfume.

Answer:

Anything which has mass and occupies space is called matter. It is made up of particles.

In the above question, chair, air, almonds, and lemon water are matters.

And love, smell, hate, thought, cold and smell of perfume are not in the category of matters because they are feeling and emotion of human beings and do not acquires any space.

Q 2.  Give reasons for the following observation:

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

Answer:

The smell of hot sizzling food reaches us from several metres away, as the particles of hot have more kinetic energy than the cold food.

So, the rate of diffusion is more in hot food as compare to cold food. 

Q 3.   A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?

Answer:

A diver is able to cut through water in a swimming pool. It shows that the particles of matter (Water) have space between them and have less inter molecular forces of attraction.

Q 4.  What are the characteristics of the particles of matter?

Answer:

There are three characteristics of the particles of matter -

  1. The particle of matter has space between them.
  2. Particles of matter are continuously moving.
  3. The particle of matter attracts each other.

 CBSE NCERT solutions for class 9 science chapter 1 Matter in Our Surroundings 

Topic 1.3 State of Matter

Q 2.(a)  Tabulate the differences in the characteristics of states of matter.

Answer:

The difference in the characteristics of three states of matter-

(i) Shape- 

  • Solid has fixed form
  • liquid has no fixed shape
  • gas has no fixed shape              

(ii) Volume-

  • Solid has fixed volume
  • the fluid has fixed volume
  • gas has no fixed volume

(iii) Rigidity/fluidity-

  • Solids are rigid and cannot flow
  • fluid can flow and have no any rigidity
  • gas can flow and have no rigidity

(iv) Intermolecular force and space-

  • Solids have a high intermolecular force and less space
  • liquid has an intermediate intermolecular force and has space more than solids
  • Gas has a very less intermolecular force and has high space 

Q 2.(b)  Comment upon the following: rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and density.

Answer:

Rigidity- The tendency of a substance to maintain their shape when subjected to an external force.

Compressibility- It means the contraction in the volume of a substance under the applied pressure. Liquid and gas are compressible because they have empty space, but solid does not.

Fluidity- The tendency of a particle to flow is known as fluidity. Liquids and gases can flow.

Filling of a gas container- The gases can fill the container with a large amount when we applied external pressure.

Shape- Solids have fixed shapes and boundaries. Liquid and gases have no fixed shape and definite boundaries.

Kinetic energy- The energy possessed by particles due to their motion is known as kinetic energy. Gas has maximum kinetic energy as they have more random motion.

Q 3.(a)   Give reasons

Answer:

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

The molecules of gas can have the tendency to move in all random direction due to their high kinetic energy. 

Q 3. (b)  Give reasons

Answer:

A gas exerts pressure on the walls of the container because the molecules of the gas are continuously in random motion because of their high kinetic energy.

So, that the molecules of gas vibrating and hitting on the walls of the container and as a result exerts pressure on walls.

Q 3.(c)   Give reasons

Answer:

A wooden table should be called a solid because it has a definite shape, fixed volume and a definite boundaries. Also, it cannot flow and incompressible.

Q 3.(d)   Give reasons 

Answer:

We can easily move our hand in the air but to do the same through a solid block of wood we need a karate expert because, in air, there is a less force of attraction between the particles. So, very less amount of external force can break it.

But in the case of solid, the force of attraction is very strong and the molecular space is so high. Hence a large amount of force is required to break it.

Q 4.  Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. Find out why.

Answer:

Ice is solid but its density is lower than that of water due to its network structure and forms a cage-like structure with a lot of vacant space. So that's why ice floats on water.

NCERT textbook solutions for class 9 science chapter 1 Matter in Our Surroundings 

Topic 1.4 Can matter change its state?

Q 1.     Convert the following temperature to Celsius scale:

a.  300 K 

b.  573 K.

Answer:

It is known that,
T_K = 273 + T_c
TK  = Temperature in Kelvin and 

T = temperature in Celsius. 

Therefore,

(i)  Temperature(C) = 300 - 273  = 27 ^0C

(ii) Temperature (C) = 573 - 273 = 300 ^0C

Q 2.   What is the physical state of water at:

a.     250ºC 
b.     100ºC

Answer:

The primary state of water is liquid at room temperature. It changes to the gaseous state above 100^0C. At 100^0C water (liquid) can be in equilibrium with the gaseous state. 

Hence, (i) At 250 ^0C physical state of water is gas. and,

             (ii) At 100 ^0C physical state of water can be gas as well as liquid.

Q 3.   For any substance, why does the temperature remain constant during the change of state?

Answer:

The temperature of the substance does not change because the heat is used to overcome the forces of attraction.

This heat energy is known as latent heat.

That is why for any substance, the temperature remain constant during the change of state.

Q 4.   Suggest a method to liquefy atmospheric gases.

Answer:

The atmospheric gases are transferred into a cylinder with a piston attached on it. By cooling and applying external pressure(by pushing the piston) on them. This way gases can be liquified.


NCERT Solutions for Class 9 Science Chapter 1 Matter in Our Surroundings

CBSE NCERT solutions for class 9 science chapter 1 Matter in Our Surroundings

Topic 1.5 Evaporation

Q 1.   Why does a desert cooler cool better on a hot dry day?

Answer:

A desert cooler cools better on a hot and dry day. It is because the inner walls of the cooler get sprinkled by the water continuously and due to warm, dry weather, this water gets evaporated.

Evaporation cause cooling of the present air inside of the cooler. This cold air is sent in the room by a fan.

Q 2.   How does the water kept in an earthen pot (matka) become cool during summer?

Answer:

The water inside the earthen pot become cold during the summer because the earthen pot is porous with a lot of pores in it. So, water comes out on the surface of the earthen pot, and this water gets evaporated.

And thus the temperature of water present inside the pot has a much lower temperature than outside, and hence water becomes cold.

Q 3.   Why does our palm feel cold when we put some acetone or petrol or perfume on it?

Answer:

When we put some acetone, petrol or perfume evaporate in our palm, they come into contact with the air and hence evaporation causes a cooling effect on our palm.

Q 4.   Why are we able to sip hot tea or milk faster from a saucer rather than a cup?

Answer:

As we know, the evaporation is rate is faster with the increased surface area. Tea in a saucer has a larger surface area than in a cup.

Therefore, the cooling of tea is more rapid in the saucer, and thus, we can sip hot tea or milk faster from a saucer rather than a cup.

Q 5.   What type of clothes should we wear in summer?

Answer:

We should wear light coloured cotton clothes because the light colours reflect the solar radiation and cotton cloths have more porosity so that it allows sweat through it to evaporate faster, thereby causing a cooling effect.

NCERT solutions for class 9 science chapter 1 Matter in Our Surroundings- Excercise solutions

Q 1.   Convert the following temperatures to the celsius scale.

(a)     293 K 
(b)     470 K.

Answer:

It is known that,
T_K = 273 + T_c
TK  = Temperature in Kelvin and 

T = temperature in Celsius. 

Therefore,

(i) Temperature (^0C)  = (293 - 273) = 20 ^0C

(ii) Temperature (^0C)  = 470 -273 = 197^0C

Q 2.   Convert the following temperatures to the kelvin scale.

(a)     25°C
(b)     373°C.

Answer:

It is known that,
T_K = 273 + T_c
TK  = Temperature in Kelvin and 

T = temperature in Celsius. 

Therefore,

(i) Temperature (K) = 273 + 25 = 298 K

(ii) Temperature (K) = 273 + 373 = 646 K

Q 3.(a)   Give reason for the following observations.

Answer:

Naphthalene balls disappear with time without leaving any solid because it can sublimise and directly converts into the gaseous state without leaving any solid.

Q 3.(b)   Give reason for the following observations.

Answer:

Perfumes contain a volatile solvent which diffuses very faster and due to this, we can get the smell of perfume sitting several meters away.

Q 4.  Arrange the following substances in increasing order of forces of attraction between the particles- water, sugar, oxygen.

Answer:

the general increasing order of forces of attraction in three states of matter is gas < liquid < solid.

Therefore increasing order for the above-given substance is-

Oxygen < water < sugar 

Q 5.   What is the physical state of water at-

(a) 25°C      (b) 0°C     (c) 100°C ?

Answer:

The primary physical state of water is liquid. It converts into gaseous state at a temperature above 100 ^0C but at this temperature, it (liquid water) is in equilibrium with the gaseous state.

And Below 0 ^0C it changes into solid and also at this temperature it (liquid water) is in equilibrium with the solid state. 

Therefore;

(i) At 25 ^0C water is in the liquid state

(ii) At 0^0C it can be liquid or solid and

(iii) At 100 ^0C it can be liquids or the gaseous state.

Q 6.(a)   Give two reasons to justify-

Answer:

 Water at room temperature is a liquid because-

  1. Below 0 ^0C it converts to ice (solid) 
  2. Above 100 ^0C it converts into the gaseous state.

Q 6.(b)  Give two reasons to justify-

Answer:

An iron almirah is a solid at room temperature because-

  1. At room temperature, it has definite shape and boundaries. Also, it has a fixed volume.
  2. The melting point of iron is much higher than room temperature.

Q 7.  Why is ice at 273 K more effective in cooling than water at the same temperature?

Answer:

At 273K ice can easily absorb more heat energy from the surrounding in the form of latent heat and overcome the fusion to become water.

Water does not absorb this extra heat from the medium.

Thus the cooling effect of ice is more than water at the same temperature.

Q 8.  What produces more severe burns, boiling water or steam?

Answer:

Steam at 100 ^0C produces more severe burns.

It is because extra heat is hidden in it called latent heat, whereas the boiling water doesn't have any this hidden heat.

Q 9.  Name A,B,C,D,E and F in the following diagram showing change in its state

            change in its state

Answer:

In the above flow chart-

A = fusion/ melting/ liquefication

B = Vaporisation/ evaporation

C = Condensation (transformation of water from a gaseous state to liquid state)

D = Solidification (the conversion of liquid into solid is known as solidification)

E = F = Sublimation 

Direct conversion of solid into gas or gas into solid without attaining the liquid phase is called sublimation.

NCERT Solutions for Class 9 Science- Chapter Wise

Chapter No.

Chapter Name

Chapter 1 

NCERT solutions for class 9 science chapter 1 Matter in our surroundings

Chapter 2

CBSE NCERT solutions for class 9 science chapter 2 Is Matter Around Us Pure

Chapter 3

Solutions for NCERT class 9 science chapter 3 Atoms and Molecules

Chapter 4

NCERT textbook solutions for class 9 science chapter 4 Structure of The Atom

Chapter 5

NCERT solutions for class 9 science chapter 5 The Fundamental Unit of Life

Chapter 6

CBSE NCERT solutions for class 9 science chapter 6 Tissues

Chapter 7

NCERT free solutions for class 9 science chapter 7 Diversity in Living Organisms

Chapter 8

solutions for NCERT class 9 science chapter 8 Motion

Chapter 9

NCERT textbook solutions for class 9 science chapter 9 Force and Laws of Motion

Chapter 10

CBSE NCERT solutions for class 9 science chapter 10 Gravitation

Chapter 11

NCERT solutions for class 9 science chapter 11 Work and Energy

Chapter 12

Solutions for NCERT class 9 science chapter 12 Sound

Chapter 13

CBSE NCERT solutions for class 9 science chapter 13 Why Do We Fall ill?

Chapter 14

NCERT free solutions for class 9 chapter 14 Natural Resources

Chapter 15

NCERT textbook solutions for class 9 science chapter 15 Improvement in Food Resources

NCERT Solutions for Class 9 - Subject Wise

NCERT Solutions for Class 9 Maths
NCERT Solutions for Class 9 Science

Key Features of NCERT solutions for class 9 science chapter 1 Matter in Our Surroundings:

  • All the NCERT solutions for the class 9 are created by experienced faculties.
  • These solutions are easy to understand.
  • Solutions of the questions given in class 9 chapter 1 Matter in Our Surroundings are as per the CBSE guidelines.
  • These NCERT solutions will assist you in your homework or assignments.
 

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