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

Class 9 NCERT Science chapter 1 Matter and its Surrounding is the topic of Chemistry. It is an important chapter which develops the foundational base among the students. Therefore, it is essential to understand each chapter from the scratch. If you encounter challenges in learning the subject on your own then you can join Saflata School online and start preparing for your board’s exam with highly qualified experts. If you are in search of the best NCERT solutions for class 9 Science then you are at the right place. Choosing Safalta’s Class 9 NCERT solutions will help you to score high grades in your exam and also aids to comprehend your answers easily. The solutions are composed by the experts keeping in mind the CBSE Syllabus and the exam requirements. Here get the Class 9 Science NCERT Solutions for all chapters also you have the access to download it in the form of a PDF for revision purposes. 
 

• Get Class 9 Science NCERT Solutions Chapter 1 Matter and in Our Surrounding
• Download PDF of NCERT Solutions for Class 9 Science Chapter 1 – Matter in Our Surroundings
• Important Concepts of NCERT Class 9 Science Chapter 1 Matter in our Surrounding
• Why take NCERT Solutions for Class 9 Science from Safalta?

 

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Get Class 9 Science NCERT Solutions Chapter 1 Matter and in Our Surrounding 

Here are all of the NCERT solutions for Class 9 Chapter 1 of Science provided. This solution covers the entirety of Chapter 1 of Science, "Matter in Our Surroundings," which was covered in class9. It includes questions, answers, illustrations, and step-by-step explanations. You must have encountered Chapter 1 of the NCERT book for Science if you are a class 9 student using it to study science. After studying the lesson, you must be seeking the lesson's questions and answers. You can find all of the NCERT solutions in one place here for Class 9 Science Chapter 1: Matter in Our Surroundings. You need also read Chapter 1 Matter in Our Surroundings Class 9 notes, Science to get a better grasp of this chapter.

Topics and Subtopics Include:

• Matter in Our Surroundings

• Physical Nature of Matter

• Characteristics of Particles of Matter

• States of Matter

• Can Matter Change its State?

• Evaporation

Check the NCERT Solutions for class 9 Science Chapter 1 below.

Download PDF of NCERT Solutions for Class 9 Science Chapter 1 – Matter in Our Surroundings

Download NCERT Solutions for Class 9 Science Chapter 1

Questions Page No. 3 

1. Which of the following are matter?

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

Answer; Chair, air, almonds, cold-drink, lemonwater and smell of perfume are the matter. As we know that matter is anything which occupies space and mass. The smell of perfume is considered a matter due to the presence of some volatile compounds in the air that occupy space and have mass, smell is regarded as a matter.

2. 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: With the increase in temperature the kinetic energy of the particles increases and thus move fast and stretch over a long distance. Likewise, hot food has a high temperature and therefore gains high kinetic energy. As we know that particles move from higher concentration regions to lower and this movement of particles is called diffusion. Hot food has a high rate of diffusion and therefore, it is capable to spread over a large distance. Whereas, cold food has low temperatures and less rate of diffusion. 

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

Answer: A drive is able to cut through water in a swimming pool as the water has great intermolecular space between them and weak forces of attraction.

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

Answer: Anything which occupies space and mass is termed as matter. Each matter is made up of particles. The following are the characteristics of the particles of matter. 

• Particles of matter have intermolecular space between them

• Particles of matter are constantly moving

• Particles of matter are continuously moving 

Question Page No. 6

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

Answer; The following substances are organised in increasing density:

Air–Exhaust from the chimneys–Cotton–Water–Honey–Chalk–Iron 
 

 2. Answer the following.

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; a) The following table shows the differences in the characteristics of states of matter

Characteristics	Solid	Liquid	Gas
Shape	Fixed shape	No Fixed shape	No Fixed shape
Volume	Fixed volume	Fixed volume	No Fixed volume
Intermolecular force	Maximum	Less than solids	Very less
Intermolecular space	Very less	More than solids	maximum
Rigidity/Fluidity	Rigid/cannot flow	Can flow/not rigid	Can flow/not rigid
Compressibility	negligible	compressible	Highly compressible

b) 

(i) Rigidity: The ability of a substance to maintain its form even after being altered using an outside force.

(ii) Compressibility: When a particle experiences a force, it can compress its intermolecular space exposed to an outside stimulus and thus increase in density.

(iii) Fluidity refers to a substance's capacity to flow or move freely.

(iv) Filling the gas container: Gases lack both exact shape and definite volume, hence they cannot be filled into a container. Gases adopt the form of the container they are filled in. Therefore, when a gas container is filled, the gas has taken on the shape of the container.

(v) Shape: Shape is a fixed volume with a definite border. Only solids have a predetermined form.

(vi) Kinetic Energy: Particles that generate energy as a result of their constant motion.

(vii) Density: Mass per unit volume is the definition of density. It is represented as d = M/V, where ‘d’ is the density, ‘M’ is the mass and ‘V’ is the volume of the substance

3. Give reasons

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

Answer: As there is relatively little force of attraction between the gas particles, they prefer to travel freely in all directions. Gas may take on the form of a container like water. As a result, we may state that gas fills the container it is kept.

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

Answer; Due to the less forces of attraction between the gas particles, they can travel freely. As a result, the force of the collisions between these gaseous particles and the container walls increases with time. The force generated by the gas particles per unit area is referred to as pressure. By doing this, we may state that gas applies pressure on the container's walls.

c) A wooden table should be called a solid.

Answer; A wooden table is quite hard by nature, meaning that it has a distinct shape that cannot be readily modified and a certain volume as well. Strong intermolecular forces have set the form, thus it has all the characteristics of a solid and is regarded as one.

d) 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.

Answer: Air particles have a lot of space between them since there aren't many forces of attraction between them. But because of the strong force of attraction between wood's particles, there is very little space between them, which is why it is said to have a hard character. We can easily move our hands in the air because of this, but we cannot do the same with a solid block of wood. We require a karate specialist for this.

4. Liquids generally have a lower density than solids. But you must have observed that ice floats on water. Find out why.

Answer: As is common knowledge, the definition of density is "mass per unit volume." The density of any material will decrease as its volume increases since their relationship is inversely proportional.

Since ice is naturally solid, it has strong intermolecular interactions that firmly bind its molecules and reduces their volume. In contrast, liquids tend to flow freely because of weak intermolecular forces and have a larger volume. This indicates that water has a propensity to float topwater due to its higher volume and lower density.

Question Page No. 9

1. Convert the following temperature to Celsius scale:

a. 300K          b. 573K

Answer: The two primary scales used to measure temperature are Celsius and Kelvin. We may obtain the value in degrees Celsius by deducting 273K from the supplied value. The following is a representation of the formula for degrees Celsius:

X°C=273K

1. 300K= (300-273)°C = 27°C

2. 573K= (573-273)°C = 300°C

2. What is the physical state of water at

a. 250°C 

Answer; Whether the matter is in a solid, liquid, or gaseous state, its physical condition is the same. Water begins to boil at a temperature of 100 °C, and at this point, water exists as a gas. This proves that water is a gas at 250°C   

b. 100°C?

Answer: Water exists in both the liquid and gaseous forms at this temperature since that is the starting point when boiling first occurs.

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

Answer: This may be explained by saying that the entire heat that we apply to the substance in order to raise its temperature is utilised to dissipate the intermolecular forces of attraction. This heat will also be the same as latent heat, which is the heat that is absorbed or released when a substance changes state. As a result, all the energy is consumed, keeping the temperature constant.

4. Suggest a method to liquefy atmospheric gases.

The gases from the atmosphere are drawn into a cylinder with a piston attached to it. The gases can be made to liquefy by cooling and exerting pressure on them.

Question Page no. 10 

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

Answer: Evaporation, the process by which liquid particles absorb energy from their surroundings and result in cooling, can be used to explain this. The amount of water vapour in the air typically affects how quickly something dries up. If there is more water vapour in the air than there is available moisture or vice versa, evaporation will occur more quickly. On a hot, dry day, there isn't a lot of water vapour in the air, so it will simply evaporate and chill the area around it. We may conclude from this that a desert cooler cools more effectively on a hot, dry day than it does on a wet one.

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

Answer: An earthen pot, or Matka, is often composed of sand particles with numerous microscopic holes, which aid in the evaporation of the water inside the pot and the cooling effect of the environment. Because of this, individuals stored water in an earthen pot throughout the summer.

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

Answer: Acetone, gasoline, and perfume are examples of organic compounds that are considered volatile in nature. Volatile substances are those that are readily evaporated and go through the evaporation process. We are aware that during the evaporation process, particles of these organic liquids absorb heat from their surroundings or the surface of the palm, causing a little amount of cooling. This explains why applying acetone, gasoline, or perfume on our hand makes us feel cold.

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

Answer: This can be described in terms of evaporation rate since, as we know, evaporation has a cooling impact and depends on surface area, with a bigger surface area resulting in more evaporation. Since there is more surface area in a saucer than a cup, evaporation will be higher if there is more surface area. As a result, we may claim that liquid cools more quickly in a saucer than it does in a cup, which explains why we can drink hot tea or milk from a saucer more quickly than a cup.

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

Answer: Since we perspire a lot in the summer, it is necessary to wear cotton or light-colored clothing since these materials may absorb more perspiration from our bodies, transmit the liquid sweat to the atmosphere, and hasten the evaporation process. When wearing cotton clothing as opposed to synthetic or woollen ones, the evaporation process creates a cooling effect that keeps our bodies cool.

Exercise Questions Page no. 12

1. Convert the following temperature to Celsius scale.

(a) 293K                (b) 470K

Solution:

The two primary scales used to measure temperature are Celsius and Kelvin. We may obtain the value in degrees Celsius by deducting 273K from the supplied value. The following is a representation of the formula for degrees Celsius:

0°C=273K

(a) 293K= (293 – 273)°C = 20°C

(b)  470K= (470 – 273)°C = 197°C

2.Convert the following temperatures to the Kelvin scale.

(a) 25°C                (b) 373°C

Solution:

The two primary scales used to measure temperature are Celsius and Kelvin. We may convert the supplied figure to degrees Celsius by subtracting 273K from it. The following is a representation of the formula for degrees Celsius:

0°C = 273K

(a) 25°C = (25+273)K = 298K

(b) 373°C = (373+273)K = 646K

3. Give reason for the following observations: 

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

Answer: The concept of sublimation, which states that a solid is transformed straight into a gas without first becoming a liquid, can be used to explain this phenomena. Naphthalene is one of the chemicals that quickly sublimates at room temperature. Because of this, it is possible to assert that naphthalene balls eventually vanish and leave nothing behind except a solid.

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

The molecules of gaseous particles are highly free to move and have a high kinetic energy since there are relatively few internuclear forces. This allows us to smell the perfume from a distance of many metres away because scent molecules interact with the surroundings and disperse into the atmosphere.

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

Answer: The ability of molecules to attract one another is what holds molecules together, and intermolecular forces are much stronger in solids than in liquids or gases. Here, it is said that sugar is solid and possesses stronger attractive forces. In comparison to other liquids, water has lower but still larger attraction forces than gases. The gas oxygen has very little inter-force attraction. As a result, the strongest forces of attraction between the particles of water, sugar, and oxygen is 

Oxygen < Water < Sugar

5. What is the physical state of water at –  

(a) 25°C 

Answer: Whether matter is in a solid, liquid, or gaseous state, its physical condition reflects that state.

Since water melts at 0° Celsius, everything beyond that point is considered to be liquid. This proves that water is liquid at 25°C.

(b) 0°C 

Ans: Water exists in both a solid and liquid state at 0°C since it is the temperature at which it begins to melt, or turn from ice to water.

(c) 100°C?

Ans: Water exists in both liquid and gaseous phases at a temperature of 100 degrees Celsius since this is the temperature at which it begins to boil.

6.Give two reasons to justify –

(a) Water at room temperature is a liquid.

Answer: The fact that water is liquid at room temperature can be explained as follows:

• Water has a certain volume but no set shape; it can adopt the shape of the container it is maintained in.

• It is inclined to flow.

• Particles are held together by weak intermolecular interactions.

All of them mention a liquid's characteristic, hence it is safe to argue that water is a liquid at ambient temperature.

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

Answer: Due to the following factors, the iron almirah in our room is regarded to be solid:

• It has a predetermined form and volume.

• Between its particles, there are powerful intermolecular forces present.

• Rigid in character and challenging to compress.

All of these define a solid's characteristics, hence we can state that an almirah is a solid at ambient temperature.

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

Answer: In this situation, ice and water are both at the same temperature, or 273 K. However, at 273 K, ice has less energy than water. This difference in energy can be attributed to the fact that water possesses latent heat of fusion, but ice lacks this form of energy. We may thus conclude that at 273 K, ice is more effective at cooling than water.
 

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

Answer: The temperature of water and steam is often accepted to be 373 K. However, steam has a higher energy content than boiling water. This may be explained in terms of the latent heat of fusion that water possesses as a secondary energy source. Consequently, burns from steam are more severe than burns from boiling water.
 

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

Answer: 

Melting is the name given to the process of changing a solid into a liquid.

Vaporization is the term for process B, which turns liquid into a gaseous state.

The process through which gases turn into liquids is referred to as condensation.

D is the method used to change liquid into solid. The process is solidification.

Sublimation is the process of turning a solid into a gas or the opposite. These processes are E and F.
 

Important Concepts of NCERT Class 9 Science Chapter 1 Matter in our Surrounding

NCERT Solutions for class 9 Science Chapter 1 is important for the study so too is the awareness about the important topic that are covered in the chapter. The following are the important concepts:

• Physical nature of matter

  • Matter is Made Up of Particles

  • How Small Are These Particles Of Matter?

• Characteristic of particles of matter

  • Particles of Matter Have Space between Them

  • Particles of Matter Are Continuously Moving

  • Particles of Matter Attract Each Other

• States of matter

  • The Solid State

  • The Liquid State

  • The Gaseous State

• Can matter change its state?

  • Effect of Change of Temperature

  • Effect of Change o Pressure

• Evaporation

  • Factors Affecting Evaporation

  • How Does Evaporation Cause Cooling?

Matter in our surrounding

The notion of matter, its definition, and the physical states in which it occurs in nature are explained in the introductory chapter.

Physical State of Matter

The three fundamental forms of matter—solid, liquid, and gas—are addressed. A diver cutting through water serves as an example of a characteristic of matter used to illustrate the argument.

Characteristics of Particles of Matter

Students learn about the many properties of matter particles in this chapter. It covers the existence of intermolecular gaps in matter particles, continuous motion in particles, and force between particles.

States of Matter

The characteristics of states of matter, including compressibility, stiffness, fluidity, kinetic energy, form, and density, are covered in Chapter 4.

Can Matter Change its State?

The example of ice changing into the water and then ultimately into gaseous form is used to illustrate the occurrence of a change in the state of matter.

Evaporation

The subject of why a desert cooler works better on a hot, dry day than other weather situations serves as an illustration of evaporation.

Why take NCERT Solutions for Class 9 Science from Safalta?

If you are confused about why to take NCERT Solutions from Safalta, there are several reasons. The following are few among them:

• Detail-oriented writing that makes sure every concept is clarified

• Written by experienced instructors and  professionals in plain language

• Contains questions from the most recent mandated curriculum

• Comprehensive review of the test questions from the previous year

• Investigate other teaching resources, such as past exam papers and example papers.

How many chapters are there in the CBSE class 9 geography textbook?

There are 15 chapters included in CBSE class 9 Science – (1) Matter in Our Surroundings, (2) Is Matter Around Us Pure, (3) Atoms and Molecules, (4) Structure of Atom, (5) The Fundamental Unit of Life, (6) Tissues, (7) Diversity in Living Organisms, (8) Motion, (9) Force and Laws of Motion, (10) Gravitation, (11) Work and Energy, (12) Sound, (13) Why do We Fall Ill, (14) Natural Resources, (15) Improvement in Food Resources.