case study class 9 matter in our surroundings

Case Study Questions Class 9 Science Matter in our Surroundings

Case study questions class 9 science chapter 1 matter in our surroundings.

CBSE Class 9 Case Study Questions Science Matter in our Surroundings. Important Case Study Questions for Class 9 Exam. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Matter in our Surroundings.

CBSE Case Study Questions Class 9 Science – Matter in our Surroundings

Case study 1:.

Answer the following questions by referring above paragraph.

ii.) Thoughts coming in our mind are example of matter. True or false

iii.) Which of the following is true about particles of matter?

b.) Particles of matter are continuously moving

Case Study 2:

Solids have a definite shape, distinct boundaries and fixed volumes, that is, have negligible compressibility. Solids have a tendency to maintain their shape when subjected to outside force. Solids may break under force but it is difficult to change their shape, so they are rigid.

Gas has very low density hence are light. Gas can flow easily and hence are called fluid.

d.) None of these

Answer key-2

Case Study 3:

Particles start vibrating with greater speed. The energy supplied by heat overcomes the forces of attraction between the particles. The particles leave their fixed positions and start moving more freely. A stage is reached when the solid melts and is converted to a liquid. The minimum temperature at which a solid melts to become a liquid at the atmospheric pressure is called its melting point.

c.) Boiling point

iv.) Define melting point and boiling point

Case Study 4:

c.) They are light weight as compare to other particles

Case Study 5:

i.) Evaporation is surface phenomenon. True or false

c.) Does not have any effect from wind speed

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• Matter in Our Surroundings Class 9 Case Study Questions Science Chapter 1

Last Updated on July 9, 2024 by XAM CONTENT

Hello students, we are providing case study questions for class 9 science. Case study questions are the new question format that is introduced in CBSE board. The resources for case study questions are very less. So, to help students we have created chapterwise case study questions for class 9 science. In this article, you will find case study questions for cbse class 9 science chapter 1 Matter in Our Surroundings.

Table of Contents

Case Study Questions on Matter in Our Surroundings

Question 1:

The word ‘matter’ refers to everything in the universe that has mass and takes up space. States of matter are generally described on the basis of qualities that can be seen or felt. Three states of matter can be found in daily life: solid, liquid and gas.

Matter that feels hard and maintains a fixed shape is called a solid, matter that feels wet and maintains its volume but not its shape is called a liquid. Matter that can change both shape and volume is called a gas.

Read the given passage carefully and give the answer of the following questions:

Q 1. In which form, do the water molecules have less kinetic energy?

d. All of them have equal kinetic energy

Q2. Which of the following describes the liquid phase?

a. It has a definite shape and a definite volume.

b. It has a definite shape but not definite volume.

c. It has a definite volume but not a definite shape.

d. It has neither a definite shape nor a definite volume.

Q 3. Which one of the following statements is wrong for gases?

a. Gases do not have a definite shape and volume.

b. Volume of the gas is equal to the volume of the container confining the gas.

c. Confined gas exerts uniform pressure on the walls of container in all directions.

d. Mass of the gas cannot be determined by weighing a container in which it is enclosed.

Q 4. ‘Gases are easily compressed but liquids cannot be compressed.’ What can be inferred from this statement?

a. The forces of attraction between gas particles are stronger than that between liquid particles.

b. The gas particles are spaced further apart than liquid particles. c. The gas particles have less energy than liquid particles.

d. The gas particles move more rapidly than liquid particles.

Q 5. As the solid melts to form liquid:

a. interparticle forces of attraction decrease

b. the kinetic energy of particles increases

c. compressibility increases

d. All of the above

Ice (solid) has less kinetic energy as compared to water (liquid) and steam (gas).

2. (c) It has a definite volume but not a definite shape.

3. (d) Mass of the gas cannot be determined by weighing a container in which it is enclosed.

The mass of a gas can be determined by weighing the empty container first, then filling it with gas and again weighing the container filled with gas. The difference of two readings gives the mass of gas.

4. (b) The gas particles are spaced further apart than liquid particles.

The large space between the particles of gas allow the gas to be easily compressed when pressure is applied.

5. (d) All of the above

When a solid is heated, the interparticle force decreases and kinetic energy of the particles increases. Compressibility of liquids is slightly more than solids, hence increase

Case study questions for other chapters of class 9 science is given below.

Is Matter Around Us Pure Class 9 Case Study Questions Science Chapter 2

We hope the given case study question

Topics from which case study questions may be asked

• Matter and its physical properties
• Characteristics pf particles of mattter
• States of Matter
• Scales of Measuring Temperature
• Evaporation
• Factors affecting Rate of Evaporation

This chapter deals with the basic understanding of acids, bases, and salts, including their properties, reactions, pH scale, indicators, and practical applications.

Frequently Asked Questions (FAQs) on Matter in Our Surroundings Case Study Questions

Q1: what are case study questions for cbse examinations.

A1: Case study questions in CBSE examinations typically involve scenarios or real-life examples, requiring students to apply their understanding of concepts to solve problems or analyze situations.

Q2: Why are case study questions important for understanding class 9 science chapters?

A2: Case study questions provide a practical context for students to apply theoretical knowledge to real-world situations, fostering deeper understanding and critical thinking skills.

Q3: How should students approach answering case study questions for CBSE?

A3: Students should carefully read the case study, identify the key issues or problems presented, analyze the information provided, apply relevant concepts and principles of chemical reactions and equations, and formulate well-supported solutions or responses.

Q4: Are there any resources available online for students to practice case study questions on class 9 science chapters for CBSE exams?

A4: Yes, several educational websites offer case study questions for CBSE students preparing for science examinations. We also offer a collection of case study questions for all classes and subject on our website. Visit our website to access these questions and enhance your learning experience. If you need more case study questions for your preparation, then you visit Physics Gurukul website.

Q5: How can students effectively prepare for case study questions on chemical reactions and equations for CBSE exams?

A5: Effective preparation strategies include regular revision of concepts, solving practice questions, analyzing case studies from previous exams, seeking clarification on doubts, and consulting with teachers or peers for guidance and support.

Q6: How can teachers incorporate case study questions on matter in our surroundings class 9 science into classroom teaching?

A6: Teachers can integrate case studies into lesson plans, group discussions, or interactive activities to engage students in active learning, promote problem-solving skills, and facilitate a deeper understanding of acids, bases and salts.

Q7: What is matter made up of?

A7: Matter is made up of particles.

Q8: What happens when salt is added to water?

A8: When we add salt in water, the particles of salt get into the spaces between particles of water. We say that salt has been dissolved into water.

Q9: What happens when we light the incense stick in one corner of a room?

A9: The smell of the incense stick spreads throughout the room due to diffusion

Q10: Which of the following substances diffuses faster in a glass of water: a drop of honey or blue ink?

A10: Blue ink, because of the high kinetic energy of the particles of the given matter. Honey is viscous, and has low kinetic energy.

Q11: Why does diffusion becomes faster on heating?

A11: On heating, the kinetic energy of the particles increases and the particles move faster. This speeds up the intermixing of particles

Q12: Why do the gases exert more pressure on the walls of the container than the solids?

A12: In gases, the particles move randomly at high speed and they collide with each other and with walls of the container. Due to this collision with walls of the container, the gases exert more pressure than solids.

Q13: What happens to the particles of the solid during sublimation?

A13: Sublimation is a process in which the solid changes directly to gas either by decreasing pressure or increasing temperature. A decrease in pressure increases the space between the particles and an increase in temperature increase the kinetic energy of the particles.

Q14: List all the factors which affects the rate of evaporation.

A14: The factors affecting the rate of evaporation are: (a) an increase in surface area (b) an increase in temperature (c) an increase in wind speed (d) a decrease in humidity

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Class 9 Science Case Study Questions Chapter 1 Matter in our Surroundings

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Case study Questions in Class 9 Science Chapter 1 are very important to solve for your exam. Class 9 Science Chapter 1 Case Study Questions have been prepared for the latest exam pattern. You can check your knowledge by solving Class 9 Science Case Study Questions  Chapter 1 Matter in our Surroundings

Join our Telegram Channel, there you will get various e-books for CBSE 2024 Boards exams for Class 9th, 10th, 11th, and 12th.

In CBSE Class 9 Science Paper, Students will have to answer some questions based on Assertion and Reason. There will be a few questions based on case studies and passage-based as well. In that, a paragraph will be given, and then the MCQ questions based on it will be asked.

Matter in our Surroundings Case Study Questions With Answers

Here, we have provided case-based/passage-based questions for Class 9 Science  Chapter 1 Matter in our Surroundings

Case Study/Passage-Based Questions

Case Study 1: There are three states of matter – solid, liquid, and gas.

Solids  have a definite shape, distinct boundaries, and fixed volumes, that is, have negligible compressibility. Solids have a tendency to maintain their shape when subjected to outside force. Solids may break under force but it is difficult to change their shape, so they are rigid.

Liquids  have no fixed shape but have a fixed volume. They take up the shape of the container in which they are kept. Liquids flow and change shape, so they are not rigid but can be called fluid.

Gas  has an indefinite shape and no fixed volume. Gas gets the shape and volume of the container.Gas has a very low density and hence is light. Gas can flow easily and hence is called fluid.

i.) Which of the following state of matter takes the shape of the container in which it is filled?

d.) Both b and c

Answer: d.) Both b and c

ii.) Distance between particles of matter least in

d.) None of these

Answer: a.) Solid

iii.) Compressibility is least in case of

Case Study 2: Matter is anything that occupies space and has mass. It exists in various forms, such as solid, liquid, and gas. The physical properties of matter, such as shape, size, and state, can be observed and measured. The particles that makeup matter are constantly in motion, and their motion determines the state of matter. In a solid, the particles are tightly packed and have a fixed shape and volume. In a liquid, the particles are close together but can move past each other, giving the substance a fixed volume but no fixed shape. In a gas, the particles are far apart and move freely, allowing the substance to occupy any volume and shape. Matter can undergo changes in its state through the processes of evaporation, condensation, melting, and freezing. Understanding the properties and behavior of matter is essential for studying various scientific phenomena and practical applications in our daily lives.

What is matter? a) Anything that occupies space and has mass b) Anything that is visible to the naked eye c) Anything that is in a solid state d) Anything that is in a gaseous state Answer: a) Anything that occupies space and has mass

What determines the state of matter? a) Physical properties b) Chemical properties c) The motion of particles d) The color of the substance Answer: c) The motion of particles

How are particles arranged in a solid? a) Far apart and move freely b) Close together but can move past each other c) Tightly packed and have a fixed shape d) Tightly packed but have no fixed shape Answer: c) Tightly packed and have a fixed shape

What is the behavior of particles in a gas? a) They are far apart and move freely b) They are close together but can move past each other c) They are tightly packed and have a fixed shape d) They are tightly packed but have no fixed shape Answer: a) They are far apart and move freely

What processes can matter undergo to change its state? a) Evaporation, condensation, melting, and freezing b) Dissolution, combustion, sublimation, and oxidation c) Fermentation, photosynthesis, respiration, and digestion d) Oxidation, reduction, precipitation, and ionization Answer: a) Evaporation, condensation, melting, and freezing

Hope the information shed above regarding Case Study and Passage Based Questions for Class 9 Science Chapter 1 Matter in our Surroundings with Answers Pdf free download has been useful to an extent. If you have any other queries about CBSE Class 9 Science Matter in our Surroundings Case Study and Passage Based Questions with Answers, feel free to comment below so that we can revert back to us at the earliest possible By Team Study Rate

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Class 9th Science - Matter in Our Surroundings Case Study Questions and Answers 2022 - 2023

By QB365 on 09 Sep, 2022

QB365 provides a detailed and simple solution for every Possible Case Study Questions in Class 9th Science Subject - Matter in Our Surroundings, CBSE. It will help Students to get more practice questions, Students can Practice these question papers in addition to score best marks.

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Matter in our surroundings case study questions with answer key.

9th Standard CBSE

Final Semester - June 2015

 Case Study 

(ii) Name the brown gas which could be in jar A.

(iii) Which is the colourless gas most likely to be present in jar B ?

(iv) When a gas jar full of air is placed upside down on a gas jar full of bromine vapours, the red-brown vapours of bromine from the lower jar go upward into the jar containing air. In this experiment : (a) air is heavier than bromine (b) both air and bromine have the same density (c) bromine is heavier than air (d) bromine cannot be heavier than air because it is going upwards against gravity (v) When a gas jar containing colourless air is kept upside down over a gas jar full of brown-coloured bromine vapour, then after some time, the brown colour of bromine vapour spreads into the upper gas jar making both the gas jars appear brown in colour. Which of the following conclusion obtained from these observations is incorrect ? (a) bromine vapour is made of tiny particles which are moving (b) air is made up of tiny particles which are moving (c) the particles of bromine are moving but those of air are not moving (d) even though bromine vapour is heavier than air, it can move up against gravity

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Matter in our surroundings case study questions with answer key answer keys.

(i) (c) diffusion (ii) (a) Bromine vapour (iii) (c) air (iv) (c) bromine is heavier than air (v) (c) the particles of bromine are moving but those of air are not moving

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Class 9 Science Chapter 1 Case Based Questions - Matter in Our Surroundings

(I) Read the given passage and answer the questions that follows based on the passage and related studied concepts. Matter is anything that occupies space and has mass. Matter is classified into solid, liquid and gas. In solid state particles are closely packed and have very strong force of attraction, particles can only vibrate and rotate around fixed positions. In liquid state, particles are less closely packed and have strong force of attraction but less than solids, particles can move throughout the liquid. In Gaseous state, particles are far apart with weak force of attraction and are in state of constant random motion. Gases can be easily compressed where as solids and liquids are incompressible. Q1: An inflated balloon is placed in refrigerator, what will happen? (a)  Balloon will shrink and particles will move faster and become closer. (b) Balloon will expand and particles will move faster and become far apart. (c)  Balloon will shrink, particles will move slower and become close together. (d) Balloon will expand, particles will move slower and come closer therefore, volume of balloon will decrease. Ans: (c) Balloon will shrink, particles will move slower and become close together.

When an inflated balloon is placed in the refrigerator, the temperature decreases. This causes the gas particles inside the balloon to move slower and come closer together, resulting in the balloon shrinking. 

Q2: When solid changes into vapours, the process is called. (a) Evaporation (b) Boiling (c)  Sublimation (d)  Vapourisation Ans:  (c)

Sublimation is the process by which a solid changes directly into a gas without passing through the liquid state.

Q3: A substance melts at 5°C and boils at 150°C. What will be its physical state at room temperature?  Ans:  Room temperature (around 25°C) is between the melting point (5°C) and the boiling point (150°C) of the substance. Therefore, the substance will be in the liquid state at room temperature. 

Q4: Why do we feel more cold after taking bath with hot water? Ans:  We feel more cold after taking a bath with hot water because when we step out of the hot water, the water on our skin starts to evaporate. The evaporation process requires heat, which is taken from our body, causing a cooling effect and making us feel colder. 

Q2: What does AB represent? Ans:  It represents a mixture of liquid and vapours at the boiling point of the liquid.

Q3: Why does temperature remain constant at boiling point? Ans: The temperature remains constant at the boiling point because the heat of vaporization is used to overcome the force of attraction between liquid particles.

Q4: What does BC represent? Ans:  It represents a vapour state, and particles absorb heat and become more energetic. The temperature of the gas will rise.

(III) Read the following information and answer the questions based on information and related studied concepts Substance – 1. is brittle. Substance – 2. melts at 5°C and boils at 150°C. Substance – 3. has high melting point of 800°C. Substance – 4. has melting point –169°C and boiling point –104°C.

Q1:  What is physical state of substance – 4 at –150°C and –100°C? Ans:   

• At –150°C: Substance – 4 will be in the solid state.
• At –100°C: Substance – 4 will be in the gaseous state.

The melting point of Substance – 4 is –169°C, and its boiling point is –104°C. Therefore, at –150°C (which is above its melting point but below its boiling point), Substance – 4 will be a solid. At –100°C (which is above its boiling point), it will be a gas.

Q2: What is physical state of substance – 1 and 3 at room temperature? Ans: 

• Substance – 1: The physical state cannot be determined solely based on the information that it is brittle. However, substances that are brittle are often solids at room temperature.
• Substance – 3: Solid.

Substance – 1: Brittle substances are typically solid (e.g., certain metals, minerals, and salts). Substance – 3: With a high melting point of 800°C, it will be in the solid state at room temperature (~25°C).

Q3: What is physical state of substance – 2 at 100°? Ans:  It will be in a liquid state.

The melting point of Substance – 2 is 5°C, and its boiling point is 150°C. Therefore, at 100°C, Substance – 2 will be in the liquid state.

Q4: Out of substances – 1, 2, 3, 4 which one has strongest force of attraction? Ans:  Substance 3 has strongest forces of attraction.

The strength of the force of attraction between particles can be inferred from the melting point. Substance – 3 has the highest melting point (800°C), indicating that it has the strongest force of attraction between its particles.

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Case Study Questions of Chapter 1 Matter in our Surroundings PDF Download

Case study Questions on Class 9 Science Chapter 1 are very important to solve for your exam. Class 9 Science Chapter 1 Case Study Questions have been prepared for the latest exam pattern. You can check your knowledge by solving case study-based questions for Class 9 Science Chapter 1 Matter in our Surroundings

In CBSE Class 9 Science Paper, Students will have to answer some questions based on Assertion and Reason. There will be a few questions based on case studies and passage-based as well. In that, a paragraph will be given, and then the MCQ questions based on it will be asked.

Matter in our Surroundings Case Study Questions With answers

Here, we have provided case-based/passage-based questions for Class 9 Science  Chapter 1 Matter in our Surroundings

Case Study/Passage-Based Questions

Question 1:

There are three states of matter – solid, liquid, and gas.

Solids  have a definite shape, distinct boundaries, and fixed volumes, that is, have negligible compressibility. Solids have a tendency to maintain their shape when subjected to outside force. Solids may break under force but it is difficult to change their shape, so they are rigid.

Liquids  have no fixed shape but have a fixed volume. They take up the shape of the container in which they are kept. Liquids flow and change shape, so they are not rigid but can be called fluid.

Gas  has an indefinite shape and no fixed volume. Gas gets the shape and volume of the container.

Gas has very low density hence is light. Gas can flow easily and hence is called fluid.

i.) Which of the following state of matter takes shape of the container in which it is filled?

d.) Both b and c

Answer: d.) Both b and c

ii.) Distance between particles of matter least in

d.) None of these

Answer: a.) Solid

iii.) Compressibility is least in case of

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

NCERT Solutions for Class 9 Science (chemistry) Chapter 1 Matter in Our Surroundings are given below. In these solutions, we have answered all the intext and exercise questions provided in NCERT class 9 science textbook. Class 9 NCERT Solutions Science Chapter 1 provided in this article are strictly based on the CBSE syllabus and curriculum. Students can easily download these solutions in PDF format for free from our app.

Class 9 Science Chapter 1 Textbook Questions and Answers

Intext Questions

Question 1:  Which of the following are matter? 

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

Answer: Chair, air, almonds, and cold-drink are matters. 

Explanation: Things that occupy space and have some mass are called matter. Since chair, air, almonds and cold-drink occupy some space and have some mass, so these are matter.

Question 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: The smell of hot sizzling food reaches severed meters away, as the particles of hot food have more kinetic energy and hence the rate of diffusion is more than the particles of cold food.

  Smell of anything comes because of gases emanating from the given thing. The smell reaches to us because of diffusion of gas. The rate of diffusion increases with increase in temperature. This happens because of higher kinetic energy due to higher temperature. That is why smell of hot sizzling food reaches to us from several feet. On the other hand, the kinetic energy of gases emanating from cold food is low because of lower temperature. Due to this, we need to move closer to a cold food to take its smell.

Question 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. This shows that the particles of water have intermolecular space and has less force of attraction.

 Question 4: What are the characteristics of particles of matter? 

Answer: The characteristics of particles of matter are:

• Particles of matter have spaces between them. 
• Particles of matter are continuously moving. 
• Particles of mater attract each other.

Question 1:  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: The given substances in the increasing order of their densities can be represented as: 

Air < Exhaust from chimney < Cotton < Water < Honey < Chalk < Iron  

Explanation:  Air is the mixture of gases. Chimney exhaust is also a mixture of gases; along with some heavier particles, such as ash. This makes the density of chimney exhaust more than air. Cotton is a porous solid and which has lot of air trapped within pores. This makes its volume more than water. Therefore, it is less dense than water.

Question 2:  (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 differences in the characteristics of states of matter are given in the following table. 

The difference in the characteristics of the three states of matter.

(b) Rigidity:  The greatest force of attraction between particles and close packing of particles make solids rigid. Rigidity is one of the unique properties of solids. Because of rigidity, a solid can resist from getting distorted. Because of rigidity a solid has definite shape and volume. Rigidity is negligible in fluid and gas.

Compressibility:  Compressibility is one of the most important characteristics of gas. Because of lot of space between particles, a gas can be compressed to a great extent.

Liquid and solid cannot be compressed because of the least space between their particles.

Fluidity:  The ability to flow is called fluidity. The less force of attraction and more space between particles make liquid and gas to flow. That’s why liquid and gas are called fluid.

Filling of a gas container:  Liquids do not fill a gas container completely, while gases fill the gas container completely in which it is kept. This is because the particles of gas can move in all the directions.

Shape:  Solids have fixed shape. Liquid and gas take the shape of the container in which they are kept. This happens because of less force of attraction and more kinetic energy between particles of liquids and negligible force of attraction and highest kinetic energy between particles of gas.

Kinetic energy:  The kinetic energy of particles of solid is the minimum. They only vibrate at their fixed position. The kinetic energy of particles of liquid is more than that of solid. But they can slide above one another. The kinetic energy of particles of gas is the maximum.

Density:  The mass per unit volume of a substance is called density. The density of solid is highest, of liquid is less than solid and of gas is minimum.

Question 3:  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:  (a) There is little attraction between particles of gas. Thus, gas particles move freely in all directions. Therefore, gas completely fills the vessel in which it is kept.

(b)  Because of negligible force of attraction between particles of gas, the particles of gas have the highest kinetic energy. These properties enable the particles of gas to move in all directions and hit the walls of container from all sides. Because of this a gas exerts pressure on the walls of the container in which it is kept.

(c) A wooden table has a definite shape and volume. It is very rigid and cannot be compressed i.e., it has the characteristics of a solid. Hence, a wooden table should be called a solid.

(d) Particles of air have large spaces between them. On the other hand, wood has little space between its particles. Also, it is rigid. For this reason, we can easily move our hands in air, but to do the same through a solid block of wood, we need a karate expert.

Since, air is gas, so its particles are loosely packed and there is negligible force of attraction between its particles. Because of that we can easily move our hand in air. But wood is a solid, so the force of attraction between its particles is greatest. The particles of wooden block are closely packed. That’s why we cannot move our hand through a solid block of wood. However, a karate expert can exert required pressure to break the great force of attraction of the particles of a solid wooden block.

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

Answer: During freezing of water, some space between the particles of water is left vacant with some air trapped between them. These empty spaces having air in them makes the density of ice; lower than that of water. That’s why ice floats on water.

Question 1: Convert the following temperatures into the Celsius scale. (a) 300 K (b) 573 K

Answer: (a) 300 K = (300 − 273)°C = 27°C (b) 573 K = (573 − 273)°C = 300°C

Question 2: What is the physical state of water at (a) 250°C  (b) 100°C

Answer: (a) Water at 250°C exists in gaseous state.

(b) At 100°C, water can exist in both liquid and gaseous form. At this temperature, after getting the heat equal to the latent heat of vaporization, water starts changing from liquid state to gaseous state.

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

Answer: During a change of state, the temperature remains constant. This is because all the heat supplied to increase the temperature is utilized (as latent heat) in changing the state by overcoming the forces of attraction between the particles. Therefore, this heat does not contribute in increasing the temperature of the substance. 

Question 4:  Suggest a method to liquefy atmospheric gases. 

Answer:  Atmospheric gas is liquefied by increasing pressure and decreasing temperature.

PAGE NO. 10

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

Answer: Desert cooler works on the basis of evaporation. In hot and dry days the moisture level is very low in atmosphere which increases the rate of evaporation. Because of faster evaporation, cooler works well. That’s why desert cooler cool better on a hot dry day.

When a liquid evaporates, the particles of the liquid absorb energy from the surroundings to compensate the loss of energy during evaporation. This makes the surroundings cool. 

In a desert cooler, the water inside it is made to evaporate. This leads to absorption of energy from the surroundings, thereby cooling the surroundings. Again, we know that evaporation depends on the amount of water vapour present in air (humidity). If the amount of water vapour present in air is less, then evaporation is more. On a hot dry day, the amount of water vapour present in air is less. Thus, water present inside the desert cooler evaporates more, thereby cooling the surroundings more.  That is why a desert cooler cools better on a hot dry day. 

Question 2:  How does water kept in an earthen pot (matka) become cool during summers?

Answer: Water from porous wall of earthen pot evaporates continuously, which lowers the temperature of water kept in the earthen pot. In summer moisture level is very low in the atmosphere, which increases the rate of evaporation as evaporation is inversely proportional to the moisture level in atmosphere. That is why in summer water kept in earthen pot becomes cool.

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

Answer: When we put some acetone or petrol or perfume on our palm, it evaporates. During evaporation, particles of the liquid absorb energy from the surrounding or the surface of the palm to compensate for the loss of energy, making the surroundings cool. Hence, our palm feels cold when we put some acetone or petrol or perfume on it.

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

Answer: When hot tea or milk is kept in a saucer, the liquid is exposed over a larger surface area as compared to in case of the liquid being kept in a cup. The larger surface area enables the faster cooling. That’s why we are able to sip hot tea or milk faster from a saucer rather than from a cup.

Question 5:   What type of clothes should we wear in summers? 

Answer: In summer, it is preferred to wear light-coloured cotton clothes because light colour reflects heat and cotton materials have pores that absorb sweat, facilitating their evaporation hence causing a cooling effect in the skin.

Question 1: Convert the following temperatures into the Celsius scale. (a) 293 K (b) 470 K

Answer: Temperature in Celsius scale = Temperature in Kelvin scale – 273

(a) 293K= (293 – 273)°C = 20°C

(b) 470K= (470 – 273)°C = 197°C

Question 2: Convert the following temperatures into the Kelvin scale.  (a) 25°C (b) 373°C

Answer: Temperature in Kelvin scale = Temperature in Celsius scale + 273

(a) 25°C = (25+273)K = 298K

(b) 373°C = (373+273)K = 646K

Question 3: Give reasons for the following observations. (a) Naphthalene balls disappear with time without leaving any solid. (b) We can get the smell of perfume while sitting several metres away.

Answer: (a) At room temperature, naphthalene balls undergo sublimation wherein they directly get converted from a solid to a gaseous state without having to undergo the intermediate state, i.e., the liquid state.

(b) Perfumes vaporize very fast and its vapours diffuse into air easily. That is why we can smell perfume sitting several meters away. 

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

Answer:  Oxygen < Water < Sugar.

Explanation: Oxygen is a gas, thus force of attraction is negligible between particles. Water is a liquid, thus force of attraction between particles is more than liquid and less than solid. Sugar is a solid, thus force of attraction between particles is greatest.

Question 5: What is the physical state of water at — (a) 25°C                       (b) 0°C                               (c) 100°C?

Answer: (a) At 25°C – water is in liquid state. (b) At 0°C – water is in solid state. (c) At 100°C – water is in transition state, i.e. in liquid and gas both.

Question 6: Give two reasons to justify: (a) water at room temperature is a liquid. (b) an iron almirah is a solid at room temperature.

Answer: (a) At room temperature (25 °C), water is a liquid because it has the following characteristic of liquid:

(i) Water has definite volume, but not definite shape as it takes the shape of the container in which it is kept. (ii) Water flows at room temperature.  

(b) An iron almirah is a solid at room temperature because: (i) It has definite shape. (ii) It has definite volume.

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

Answer: At 273K ice requires more latent heat to melt into water, while water at 273K requires less latent heat; to come to the room temperature. So, ice at 273 K is more effective in cooling than water at the same temperature.

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

Answer: Steam produces more severe burns than boiling water. This is because steam has more energy than boiling water, present in it in the form of latent heat of vaporization.

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

Answer: A: Melting (or) fusion (or) liquefaction B: Evaporation (or) vaporization C: Condensation D: Solidification E: Sublimation F: Sublimation

Class 9 Science NCERT Solutions Chapter 1 Matter in Our Surroundings

CBSE Class 9 Science NCERT Solutions Chapter 1 helps students to clear their doubts and to score good marks in the board exam. All the questions are solved by experts with a detailed explanation that will help students complete their assignments & homework. Having a good grasp over CBSE NCERT Solutions for Class 9 Science will further help the students in their preparation for board exams and other competitive exams such as NTSE, Olympiad, etc.

NCERT Solutions for Class 9 Science Chapter 1 PDF

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Matter in Our Surroundings Class 9 Extra Questions Science Chapter 1

October 2, 2019 by Sastry CBSE

Extra Questions for Class 9 Science Chapter 1 Matter in Our Surroundings

Matter in Our Surroundings Class 9 Extra Questions Very Short Answer Questions

Question 1. Is there any similarity in materials? Answer: Yes, all materials possess mass and occupy space.

Question 2. When 50 g of sugar is dissolved in 100 mL of water, there is no increase in volume. What characteristic of matter is illustrated by this observation? Answer: This observation indicates that particles of water have spaces between them into which sugar particles fit.

Question 3. What happens when an inflated air balloon is pricked with a pin? Name the property of the gaseous state exhibited by this observation. Answer: The balloon bursts and diffusion takes place.

Question 4. Name the process which occurs when a drop of dettol is added to water. Answer: When dettol is added to water, diffusion takes place.

Question 5. To which physical state of matter do the following statements apply? (i) Incompressible, no fixed shape (ii) Compressible, no definite volume Answer: (i) Liquid (ii) Gas

Question 6. Name the state of matter in which: (i) Layers of particles can slip and slide over one another easily. (ii) Particles just move around randomly because of very weak force of attraction. Answer: (i) Liquid state, (ii) Gaseous state.

Question 7. Define density and give its SI unit. Answer: Density of a substance is defined as the mass per unit volume. Its SI unit is kgm -3 .

Question 8. In which of the following, the particles have highest forces of attraction? Water, NaCl (solid), ice or, wax. Answer: NaCl (solid) has particles with the highest forces of attraction.

Question 9. Why do the gases exert more pressure on the walls of the container than the solids? Answer: In gases, the particles move randomly at high speed and they collide with each other and with the walls of the container.

Question 10. Which of the following diffuses faster? Water vapour, wax or, ethyl alcohol. Answer: Water vapour

Question 11. Why do we see water droplets on the outer surface of a glass containing ice cold water? Answer: The water vapour present in the air comes in contact with cold surface of the glass, loses its energy and gets converted into droplets of water.

Question 12. Can materials exist in all the three states? Answer: Yes, materials can exist in all the three states under different conditions of temperature and pressure.

Question 13. Kinetic energy of particles of water in three vessels A, B and C are E A , E B and E C respectively and E A > E B > E C . Arrange the temperatures, T A , T B and T C of water in the three vessels in increasing order. Answer: T C < T B < T A , the kinetic energy of particles is greater at higher temperature.

Matter in Our Surroundings Class 9 Extra Questions Short Answer Questions-I

Question 1. When a crystal of potassium permanganate is placed in a beaker containing water, its purple colour spreads throughout the water. What do you conclude from this observation about the nature of potassium permanganate and water? Answer: When we place few crystals of potassium permanganate in a beaker containing water, we get two distinct layers—colourless water at the top and pink colour at the bottom. After few minutes, pink colour spreads and whole solution turns pink due to diffusion. Since potassium permanganate is a solid substance, it does not possess so much space. Water molecules due to liquid state, collide with solid particles and intermix due to sufficient space between molecules.

Question 2. Why do solids have a regular geometrical shape? Answer: In solids, the particles have highly ordered arrangement because the intermolecular forces between the particles are very strong. Therefore, solids have a regular geometrical shape.

Question 3. Why are gases compressible but not liquids? Answer: Gases are compressible because the intermolecular space is very large in gases, whereas liquids are not compressible because in liquids, the intermolecular space is less.

Question 4. Can a rubber band change its shape on stretching? Is it a solid? Answer: Yes, a rubber band changes shape under force and regains the same shape when the force is removed. It breaks on applying excessive force. Yes, it is a solid.

Question 5. Why steam at 100°C is better for heating purposes than water at 100°C? Answer: Steam at 100°C is better for heating purposes than water at 100°C because the energy of 1 kg of steam at 100°C is 22.6 × 10 5 joule which is more than that of 1 kg of water at the same temperature.

Question 6. Give two ways in which melting points and boiling points can be useful. Answer:

• To check whether the substance is pure or not.
• To identify and characterise the substance.

Question 7. Alka was making tea in a kettle. Suddenly she felt intense heat from the puff of steam gushing out of the spout of the kettle. She wondered whether the temperature of the steam was higher than that of the water boiling in the kettle. Comment. [NCERT Exemplar] Answer: The temperature of both boiling water and steam is 100°C, but steam has more energy because of latent heat of vaporisation.

Question 8. Why does the temperature of a substance remain constant during its melting point or boiling point? [NCERT Exemplar] Answer: The temperature of a substance remains constant at its melting and boiling points until all the substance melts or boils because, the heat supplied is continuously used up in changing the state of the substance by overcoming the forces of attraction between the particles. This heat energy absorbed without showing any rise in temperature is given the name latent heat of fusion/latent heat of vaporisation.

Question 9. What do you understand by the term ‘latent heat of fusion’? How much is the latent heat of fusion of ice? Answer: The amount of heat that is required to change 1 kg of solid into liquid at atmospheric pressure without any change in temperature at its melting point, is known as latent heat of fusion. The latent heat of fusion of ice in SI unit is 3.35 × 10 5 J/kg.

Question 10. Which gas is called dry ice? Why? Answer: Solid CO 2 is known as dry ice. This is because it directly gets converted into gaseous state without passing through liquid state on decreasing the pressure to 1 atmosphere.

Question 12. Why do the doctors advise to put strips of wet cloth on the forehead of a person having high fever? Answer: When a person has fever, his body temperature becomes more than the normal body temperature. If we put strips of wet cloth on the forehead of a person suffering from high fever, the water evaporates taking heat from the body. Thus, moist strips will lower his body temperature.

Question 14. Why do wet clothes dry quickly in the sun than in the shade? Answer: The temperature in the sunny area is higher than in the shade and evaporation takes place at a faster rate at high temperature. Hence, wet clothes dry quickly in the sun.

Question 15. Why do trees acquire more leaves during summer? Answer: During summer the temperature is generally very high. In order to keep cool, a tree must transpire (transpiration is a phenomenon of evaporation of water from the leaves) more to keep itself cool. More transpiration requires more leaves. Hence, a tree acquires more leaves during summer.

Question 16. Why do we feel comfortable under a fan when we are perspiring? Answer: The sweat is readily evaporated from the body by the air from the fan. As a result, we feel comfortable under a fan.

Question 17. Why do people sprinkle water on the roof after a hot sunny day? Answer: Water sprinkled on the roof evaporates by taking the large latent heat of vaporisation from the ground. This makes the place cool and comfortable.

Question 18. It is a hot summer day, Priyanshi and Ali are wearing cotton and nylon clothes respectively. Who do you think would be more comfortable and why? [NCERT Exemplar] Answer: Priyanshi would be more comfortable because cotton is a good absorber than nylon. It absorbs sweat from the body and provides large surface area for evaporation which causes cooling effect. As a result, body feels cool and comfortable.

Matter in Our Surroundings Class 9 Extra Questions Short Answer Questions-II

Question 1. Substance ‘A’ has high compressibility and can be easily liquefied. It can take up the shape of any container. Predict the nature of the substance. Enlist four properties of this state of matter. Answer: ‘A’ is a gas. Properties of gases:

• They do not have fixed shape and fixed volume.
• They have large interparticle space.
• They have least forces of attraction between the molecules.
• They are highly compressible.

Question 2. Suggest an activity to show that the rate of diffusion of liquids decreases with increase in density of the liquid. Answer:

• Take two beakers filled with water.
• Put a drop of blue ink slowly along the sides of the first beaker and honey in the same way in another beaker.
• Leave it undisturbed.
• We observe that honey diffuses slowly as compared to ink.

This experiment shows that lesser the density, faster the rate of diffusion.

Question 3. Classify the following into osmosis/diffusion

• Swelling up of a raisin on keeping in water.
• Spreading of virus on sneezing.
• Earthworm dying on coming in contact with common salt.
• Shrinking of grapes kept in thick sugar syrup.
• Preserving pickles in salt.
• Spreading of smell of cake being baked throughout the house.
• Aquatic animals using oxygen dissolved in water during respiration. [NCERT Exemplar]

Question 4. Explain what happens to the molecular motion and energy of 1 kg of water at 273 K when it is changed into ice at same temperature. How is the latent heat of fusion related to the energy exchange that takes place during this change of state? Answer:

• Molecular motion decreases as water gets converted into ice.
• Latent heat of solidification is given off.

Latent heat of solidification is equal to latent heat of fusion.

• Take crystals of ammonium chloride in a china dish.
• Put the china dish on a tripod stand with wire gauze.
• Put an inverted funnel on the china dish and insert a cotton plug in the stem of the funnel.
• Heat the china dish on a low flame.
• In the inside of the funnel white deposits of ammonium chloride is seen which directly converts into gaseous state and then solidifies.

Question 8. Explain how the rate of evaporation of a liquid is affected with:

• Increase in temperature of the liquid.
• Decrease in exposed surface area.
• Increase in moisture in the surrounding air.
• Increase in wind speed.
• Rate of evaporation increases with rise in temperature.
• Evaporation is less when exposed surface area decreases.
• Less evaporation if moisture content is high in the air.
• Rate of evaporation increases if wind speed increases.

Question 9. You want to wear your favourite shirt to a party, but the problem is that it is still wet after a wash. What steps would you take to dry it faster? [NCERT Exemplar] Answer: Conditions that can increase the rate of evaporation of water are:

• An increase in the surface area by spreading the shirt.
• An increase in the temperature by putting the shirt under the sun.
• Increase in the wind speed by spreading it under the fan.

Question 10. How does evaporation differ from boiling? Answer:

Matter in Our Surroundings Class 9 Extra Questions Long Answer Questions

Question 1. Describe the continuous motion of particles of matter with the help of an activity. Answer: (a) To demonstrate motion of particles in air:

• Place few lighted incense sticks in a corner of a room.
• Move about the room and smell the fragrance of the incense sticks.

The fragrance produced due to burning of incense sticks is due to movement of vapours produced rapidly in all directions.

(b) To demonstrate motion of particles of solid matter:

• Drop a crystal of copper sulphate or potassium permanganate into a glass of hot water.
• Do not stir the solution and allow the crystals to settle at the bottom.
• The colour of the solid is seen spreading slowly. This is because the solid particles diffuse in the water.

• In a beaker take some water and insert a thermometer in it with the help of a clamp.
• Put the beaker on a tripod stand and heat the apparatus with the help of kerosene burner slowly.
• Observe what happens to water.
• You will observe a steady stream of bubbles. This temperature is the boiling point of water.

Determination of melting point of ice:

• Take crushed ice in a beaker and insert a thermometer in the beaker by hanging it from the clamp of the stand in such a way that the bulb of the thermometer is completely inside the ice.
• Wait for some time and keep recording the temperature after small intervals of time.
• Note down the temperature when ice just starts melting.
• Let the bulb of the thermometer remain in mixture of ice and water for some more time and keep recording the temperature. This temperature is the melting point of ice.

Question 4. Discuss the various factors which affect the rate of evaporation. Latent heat of evaporation of two liquids A and B is 100 J/kg and 150 J/kg respectively. Which one can produce more cooling effect and why? Answer: Factors affecting the rate of evaporation:

• Surface area: The rate of evaporation increases with increase in surface area.
• Temperature: The rate of evaporation increases with increase in temperature.
• Humidity: The rate of evaporation decreases with increase in humidity.
• Wind speed: The rate of evaporation increases with increase in wind speed.
• Nature of the liquid: The volatile compounds evaporate faster than less volatile compounds (liquids).

B will produce more cooling effect because it will absorb more heat from the surroundings for evaporation.

Question 5. Comment on the following statements: (a) Evaporation causes cooling. (b) Rate of evaporation of an aqueous solution decreases with increase in humidity. (c) Sponge though compressible is a solid. (d) Ice is solid at 0°C, while water is liquid at room temperature. (e) Sugar crystals dissolve faster in hot water than cold water. [NCERT Exemplar] Answer: (a) Evaporation produces cooling as the particles at the surface of the liquid gain energy from the surroundings and change into vapour, thereby producing a cooling effect. (b) Air around us cannot hold more than a definite amount of water vapour at a given temperature which is known as humidity. So, if the air is already rich in water vapour, it will not take up more water; therefore, rate of evaporation of water will decrease. (c) A sponge has minute holes in which air is trapped. Also the material is not rigid. When we press it, the air is expelled out and we are able to compress it. But it is a solid because it has definite shape and volume and does not change its shape unless compressed. (d) Ice is solid at 0°C because it has a definite volume and definite shape due to strong intermolecular forces. Water is liquid at room temperature because it has definite volume and no definite shape due to weak intermolecular forces of attraction. (e) Sugar crystals dissolve faster in hot water than cold water because hot water molecules have more kinetic energy. Due to this, they strike faster on the particles of sugar than cold water molecules. As a result, hot water will dissolve them faster than cold water.

Matter in Our Surroundings Class 9 Extra Questions Hots (Higher Order Thinking Skills)

Question 2. ‘A small volume of water in a kettle can fill a kitchen with steam’. Explain why. Answer: The liquid form of water converts into gaseous form in steam. Its particles move very rapidly in all the directions and fill the kitchen as gases completely fills the vessel.

Question 3. A sample of water under study was found to boil at 102°C at normal temperature and pressure. Is the water pure? Will this water freeze at 0°C? Comment. [NCERT Exemplar] Answer: Its freezing point will be below 0°C due to the presence of a non-volatile impurity in it.

Question 4. You are given the following substances with their melting and boiling points.

Identify the physical states of X, Y and Z at room temperature (30°C). Answer: ‘X’ is gas at room temperature. ‘Y’ is solid at room temperature. ‘Z’ is liquid at room temperature.

Question 7. Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations. [NCERT Exemplar] Answer: In case of ice, the water molecules have low energy while in case of steam the water molecules have high energy. The high energy of water molecules in steam is transformed as heat and may cause burns. On the other hand, in case of ice, the water molecules take energy from the body and thus, give a cooling effect.

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Matter in Our Surroundings Class 9 Extra Questions and Answers Science Chapter 1

August 27, 2020 by Veerendra

In this page, we are providing Matter in Our Surroundings Class 9 Extra Questions and Answers Science Chapter 1 pdf download. NCERT Extra Questions for Class 9 Science Chapter 1 Matter in Our Surroundings with Answers will help to score more marks in your CBSE Board Exams.

Class 9 Science Chapter 1 Extra Questions and Answers Matter in Our Surroundings

Extra Questions for Class 9 Science Chapter 1 Matter in Our Surroundings with Answers Solutions

Matter in Our Surroundings Class 9 Extra Questions Very Short Answer Type

Question 1. Define the term ‘matter’. Answer: Matter is defined as anything that occupies some space and has definite mass.

Question 2. What is Law of Conservation of Mass? Answer: Law of Conservation of Mass states that mass can neither be created nor destroyed in a chemical reaction.

Question 3. Define melting point. Answer: It is the temperature at which a solid becomes liquid at atmospheric pressure by absorbing heat.

Question 4. Out of water and alcohol, which is more volatile? Answer: The boiling point of alcohol (78°C or 351K) is lower than that of water (100°C or 373K), therefore, alcohol is more volatile than water.

Question 5. What is sublimation? Answer: Direct conversion of a solid into vapour and vice-versa (i.e., vapour into solid) is called sublimation.

Question 6. Is dry ice the same thing as ordinary ice? Answer: No, dry ice is solid carbon dioxide while ordinary ice is solid water.

Question 7. Define latent heat of fusion. Answer: It is the heat energy required to convert 1 kg of solid into liquid at its melting point at atmospheric pressure.

Question 8. Define vapourisation. Answer: The process of change from liquid state to gaseous (vapour) state is called vapourisation.

Question 9. Give the important properties on the basis of which the three states of matter can be distinguished. Answer: The three states of matter can distinguished on the basis of shape, volume, compressibility, packing of molecules, number of free surfaces, etc.

Question 10. Name the term used for the solid which is directly formed from the gas. Answer: Sublimate.

Question 11. Define the term volatile liquid. Answer: Those liquids which can change into vapour easily are termed as volatile liquids.

Question 12. What is the effect of pressure on boiling point? Answer: Boiling point increases with increase in pressure.

Question 13. Name any two substances which sublime. Answer: Camphor, napthalene, iodine, ammonium chloride.

Question 14. Define condensation. Answer: The change of a gaseous state to a liquid state on cooling is known as condensation.

Question 15. State the effect of surface area on rate of evaporation. Answer: If the surface area is increased, the rate of evaporation increases.

Question 16. Define evaporation. Answer: Evaporation is a physical process in which a liquid changes to its gaseous state, at a temperature lower than its boiling point.

Question 17. What are the ways in which a gas can be liquefied? Answer: Applying pressure and reducing temperature can liquefy gases.

Question 18. What is plasma? Answer: It is a state of matter which consists of super energetic and super excited particles. These particles are in the form of ionised gases.

Question 19. How do solids, liquids and gases differ in shape and volume? Answer: Solids have a definite shape and a fixed volume, liquids have a definite volume but no fixed shape while gases neither have a definite volume nor a definite shape.

Question 20. Kelvin scale of temperature is regarded as better scale than Celsius. Why? Answer: As it has a wide range of measurement and temperature in kelvin scale always has a positive sign, hence regarded as better scale than Celsius.

Matter in Our Surroundings Class 9 Extra Questions Short Answer Type 1

Question 1. What are characteristics of particles of matter? Answer: The particles of matter have following characteristics:

• Particles of matter are very very small.
• Particles of matter have space between them.
• Particles of matter attract each other.
• Particles of matter are constantly moving.

Question 2. Write four main characteristics of solid state of matter. Answer:

• Solids have definite mass, volume and shape.
• The particles in solid state are closely packed and empty spaces in them are negligible.
• Solids are rigid.
• Solids can have a number of free surfaces.

Question 3. Write four main characteristics of liquid state of matter. Answer:

• Liquids have a definite mass and volume.
• A liquid can take the shape of a container.
• Liquids have only one free surface.
• Liquids show the property of diffusion.

Question 4. Write four characteristics of gaseous state of matter. Answer:

• A gas has definite mass but it has neither definite shape nor definite volume.
• Gases can occupy the whole of the space available to them.
• There are larger vacant spaces between the molecules of a gas.
• Gases are highly compressible.

Question 5. Explain evaporation and its cooling effect in terms of kinetic energy of particles. Answer: During evaporation, the molecules which possess higher kinetic energy leave the liquid and go into the space above the liquid as vapour. The remaining molecules possessing lower kinetic energy are left in the liquid state. Consequently, the average kinetic energy decreases which results in the fall of temperature of the liquid.

Question 6. How is heat transferred when a solid sublimes? Answer: Certain solids like iodine, naphthalene, solid CO 2  sublimes on heating. Heat is absorbed by the molecules of these solids rapidly which provides enough kinetic energy to show phase change into gaseous state.

Question 7. Why do gases diffuse rapidly? Answer: Gases diffuse rapidly due to high speed of the particles and large space between them.

Question 8. For any substance, why does the temperature remain constant during the change of state? Answer: On increasing the temperature of a substance, for example a solid, the kinetic energy of the particles increases which is used to overcome the forces of attraction between the particles therefore the temperature remains constant during the change of state.

Question 9. Explain compressibility in gases with an example. Answer: Liquefied petroleum gas (LPG) cylinders are used in our homes for cooking, contains gases in the compressed state. Similarly, compressed natural gas (CNG) is used as a fuel in vehicles. Large volume of gases can be compressed in small cylinders and are transported to distant places.

Question 10. Why solids cannot be compressed like gases? Answer: The particles in solids are so tightly packed that there are no or little interparticle spaces left among them. Therefore solids are not compressible like gases. Gases which have large interparticle spaces are therefore compressible.

Question 11. Define boiling. Why is boiling considered as bulk phenomenon? Answer: Rapid and breaking of bubbles in the bulk of a liquid being heated is called boiling. During boiling particles from the bulk of liquid gain enough energy to get converted to vapour. Therefore it is a bulk phenomenon.

Question 12. Why do we see water droplets on the outer surface of a glass containing ice-cold water? Answer: The water vapour present in air, on coming in contact with the cold glass of water, loses energy and gets converted to liquid state, which we see as water droplets.

Question 13. Why do we sprinkle water on the roof or open ground in summer? Answer: During hot summer evenings, we often sprinkle water on the roof of the house or open ground in front of our house. The water evaporates by absorbing heat from the ground and the surrounding air. By losing heat, the ground becomes cool and we feel comfortable.

Question 14. Why is ice rubbed on a burnt part of the skin? Answer: When a finger or some part of our body gets burnt, we rub the burnt portion with an ice cube. The reason being that due to burning, the temperature of the injured skin increases. When ice is rubbed, the excess heat from the skin is taken away by large latent heat of fusion of water. As a result, the temperature of the injured skin decreases and we feel less pain.

Question 15. How will you demonstrate that particles of matter are continuously moving? Answer: When an incense stick is lit in one corner of a room, we get the smell while sitting at a distance from the stick. This is because the particles of matter are continuously moving. Because of their random motion, the particles of incense mix with the particles of air rapidly and the smell of the incense reaches us even when we are sitting at a distance from the incense stick.

Question 16. Why do solids expand a bit on heating and contract a bit on cooling? Answer: The solid molecules do not have sufficient intermolecular (or interparticle) space thus its expands a bit on heating. The interparticle forces of attraction are very strong which do not let solid particles leave their mean positions. Therefore solid contracts a bit on cooling.

Question 18. Why is light not considered matter? Answer: Matter occupies space and has mass. Light has neither of the two and that is why it is not considered as matter. It is considers as a form of energy and electromagnetic radiation.

Question 19. Convert the following temperatures: (a) – 78.0°C to kelvin (b) 775 K to °C (c) 489 K to °C (d) 24°C to kelvin Answer: (a) – 78 + 273 = 195 K (b) 775 – 273 = 502°C (c) 489-273 = 216°C (d) 24 + 273 = 297 K

Question 20. Mention the difference between gas and vapour. Answer: Gas – The gas is a substance which exists in the gaseous state at a temperature equal to or more than the boiling point of its liquid state. For example oxygen, hydrogen, nitrogen, etc.

Vapour – A vapour is a substance which exists in the gaseous state such that its temperature is lower than that of boiling point of its liquid state. For example, water vapour, iodine vapour, etc.

Question 21. A sample of water under study was found to boil at 102″C at normal temperature and pressure. Is the water pure? Will this water freeze at 0°C? Comment. Answer: It’s freezing point will be below 0°C due to the presence of a non-volatile impurity in it.

Question 22. Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations. [NCERT Exemplar] Answer: In case of ice, the water molecules have low energy while in the case of steam the water molecules have high energy. The high energy of water molecules in steam is transformed as heat and may cause burns. On the other hand, in case of ice, the water molecules take energy from the body and thus gave a cooling effect.

Question 23. It is a hot summer day, Priyanshi and Ali are wearing cotton and nylon clothes respectively. Who do you think would be more comfortable and why? [NCERT Exemplar] Answer: Cotton being a better absorber of water than nylon helps in absorption of sweat followed by evaporation which leads to cooling. So Priyanshi would be more comfortable than Ali.

Question 24. You want to wear your favourite shirt to a party, but the problem is that it is still wet after a wash. What steps would you take to dry it faster? [NCERT Exemplar] Answer: Conditions that can increase the rate of evaporation of water are:

• An increase of surface area by spreading the shirt
• An increase in temperature by putting the shirt under the Sun
• An increase the wind speed by spreading it under the fan.

Matter in Our Surroundings Class 9 Extra Questions HOTS

Question 1. Arrange the following substances in increasing order of force of attraction between the particles. (a) Milk (b) Salt (c) Oxygen Answer: Oxygen < Milk < Salt.

• Take two balloons of different shapes. For example, one round and one heart shape or cylindrical.
• Fill the balloons with air.

Observation: Air takes up the shape of balloon.

Conclusion: This shows air has no definite shape or volume. It takes up the shape of the balloon.

Question 3. Name the change of state during the following changes: (a) Drying of wet clothes (b) Melting of wax (c) Melting of ice (d) Formation of clouds Answer: (a) Liquid to gaseous state (b) Solid to liquid state (c) Solid to liquid state (d) Liquid to gaseous state

Question 4. With proper explanation, explain whether the following statements are true or false? (a) Sublimation occurs only when the solid is heated. (b) A lighter gas can move downwards and a heavier gas can move upwards. (c) Interconversion of matter is a constant temperature process. Answer: (a) Statement is wrong. Sublimation may occur on its own or by heating, e.g., camphor, naphthalene, iodine, etc., sublime slowly at room temperature.

(b) Statement is true. Diffusion occurs against the law of gravitation. Therefore, lighter gases can also diffuse downwards and the heavier gases can also diffuse upwards. However rate of diffusion of lighter gases is faster than those of heavier gases.

(c) Statement is true. During interconversion of state of matter from solid to liquid or from liquid to gas, it tends to reach its melting point or boiling point. At this point, the temperature remains constant unit it has changed in another state.

Question 5. What is meant by Bose-Einstein Condense? Answer: (a) In 1920, Indian scientist Satyendra Nath Bose did some calculations, based on which Albert Einstein predicted that a new state of matter should exist.

(b) This new state was named as Bose-Einstein Condensate (BEC). In 2001, Cornell, Ketterie and Wieman of USA received Noble Prize for actually making this state in laboratory. BEC is made by cooling gas of very low density to super low temperature.

Matter in Our Surroundings Class 9 Extra Questions Value Based (VBQs)

Question 1. In a hot summer day, Rajeev wants to watch a movie in a nearest cineplex. His mother wears a nylon saree so Rajeev suggest her to wear cotton saree. (i) Why does Rajeev suggest her to wear cotton saree and not nylon saree? (ii) Mention the values exhibited by Rajeev. Answer: (i) On a hot summer day, we sweat a lot. Cotton clothes absorb sweat from the body. As the sweat evaporates it results in cooling giving comfort to the body.

(ii) Caring, use of knowledge of science.

Question 2. Mohan was getting late for school. He tried to sip tea from the cup. His father advised him to use a plate and asked him to sip the tea from the plate. Mohan followed the advice and finished his tea very easily. (i) Why is siping off tea easier from a plate? (ii) Mention the values exhibited by Mohan’s father. Answer: (i) A plate has a larger surface area than a cup. Evaporation becomes faster in this case. Since cooling is always caused during evaporation the temperature got lowered. Therefore it became easier to sip tea from a plate.

(ii) Caring, use of knowledge of science, helpful.

• NCERT Exemplar
• Science Exemplar Class 9
• Matter In Our Surroundings

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

Ncert exemplar solutions class 9 science chapter 1 – free pdf download.

The NCERT Exemplar Solution for Class 9 Science Chapter 1 Matter in Our Surrounding is provided here for the benefit of the students. Studying the NCERT Exemplar Solution will give you in-depth knowledge of the concepts discussed in the chapter. NCERT Exemplar questions are designed in such a way that students can learn all the basic and advanced concepts of the chapter – Matter in Our Surroundings – in a better and easy way.

This Exemplar Solution has answers to questions provided in the NCERT Exemplar Class 9 Science book. It has 10 multiple choice questions, 12 short answer questions and 5 long answer questions of varied difficulty, which will help you to face the exam confidently. To get good marks in the Class 9 examination and to lay a strong foundation for the topics to be studied in future, students are advised to refer to the NCERT Exemplar .

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

Access Answers to the NCERT Exemplar for Class 9 Science Chapter 1 – Matter in Our Surroundings

Multiple choice questions.

1. Which one of the following sets of phenomena would increase on raising the temperature?

(a) Diffusion, evaporation, compression of gases

(b) Evaporation, compression of gases, solubility

(c) Evaporation, diffusion, expansion of gases

(d) Evaporation, solubility, diffusion, compression of gases

Answer is c) Evaporation, diffusion and expansion of gases

Explanation:

Particles of matter are continuously moving as they possess kinetic energy. When temperature is raised particles of matter intermix with each other which is called diffusion.

Evaporation means conversion of liquid state into vapour state. When we increase temperature molecules move and vibrate so quickly that they escape into the atmosphere in the form of vapours.

Increase in temperature causes the molecules to move faster, which results in expansion of gases.

2. Seema visited a Natural Gas Compressing Unit and found that the gas can be liquefied under specific conditions of temperature and pressure. While sharing her experience with friends she got confused. Help her to identify the correct set of conditions

(a) Low temperature, low pressure

(b) High temperature, low pressure

(c) Low temperature, high pressure

(d) High temperature, high pressure

Answer is c) Low temperature, high pressure

To compress gas into liquid, low temperature and high pressure are required. Between the particles of gas there is a lot of space. On applying pressure, particles get closer and they start attracting each other to form a liquid. A lot of heat is generated when gas is compresses hence it is necessary to cool it. Cooling lowers the temperature of compressed gas and helps in liquefying it.

3. The property to flow is unique to fluids. Which one of the following statements is correct?

(a) Only gases behave like fluids

(b) Gases and solids behave like fluids

(c) Gases and liquids behave like fluids

(d) Only liquids are fluids

Answer is c) Gases and liquids behave like fluids

In gases and liquids intermolecular force of attraction between the particles is less and they facilitate flow of these states of matter.

4. During summer, water kept in an earthen pot becomes cool because of the phenomenon of

(a) diffusion

(b) transpiration

(c) osmosis

(d) evaporation

Answer is d) evaporation

Evaporation of water through pores of earthen pot reduces temperature of immediate surroundings. This makes the water cool after some time.

Movement of water through plants and evaporation through its aerial parts is called transpiration.

Diffusion is the movement of a substance from an area of higher concentration to an area of lower concentration

If molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, it is called osmosis.

5. A few substances are arranged in the increasing order of ‘forces of attraction’ between their particles. Which one of the following represents a correct arrangement?

(a) Water, air, wind

(b) Air, sugar, oil

(c) Oxygen, water, sugar

(d) Salt, juice, air

Answer is c) Oxygen, water, sugar

The intermolecular force of attraction is less in gases than liquid and solid. Solids have higher intermolecular attraction compared to liquid. In the answer, oxygen is a gas which has lesser intermolecular attraction than water-a liquid and sugar- a crystalline solid.

6. On converting 25°C, 38°C and 66°C to kelvin scale, the correct sequence of temperature will be

(a) 298 K, 311 K and 339 K

(b) 298 K, 300 K and 338 K

(c) 273 K, 278 K and 543 K

(d) 298 K, 310 K and 338 K

Answer is a) 298 K, 311 K and 339 K

Add 273 to respective temperature to get the temperature in kelvin. 25°-298K, 38°-311K, 66°-339K

7. Choose the correct statement of the following

(a) Conversion of solid into vapours without passing through the liquid state is called sublimation.

(b) Conversion of vapours into solid without passing through the liquid state is called vaporisation.

(c) Conversion of vapours into solid without passing through the liquid state is called freezing.

(d) Conversion of solid into liquid is called sublimation.

Answer is a) Conversion of solid into vapours without passing through the liquid state is called sublimation.

• Sublimation is a process in which a solid is converted into vapours without passing through a liquid state.
• Vaporisation is a phase transition from liquid to vapours.
• Conversion of liquid to solid at substance’s freezing temperature is called as freezing.

8. The boiling points of diethyl ether, acetone and n-butyl alcohol are 35°C, 56°C and 118°C respectively. Which one of the following correctly represents their boiling points in kelvin scale?

(a) 306 K, 329 K, 391 K

(b) 308 K, 329 K, 392 K

(c) 308 K, 329 K, 391 K

(d) 329 K, 392 K, 308 K

Answer is c) 308 K, 329 K, 391 K

The temperature in Celsius can be converted into temperature in kelvin by adding 273 to the Celsius value. Boiling points of diethyl ether, acetone and n-butyl alcohol are 308 K, 329 K, and 391 K, respectively.

9. Which condition out of the following will increase the evaporation of water?

(a) Increase in temperature of water

(b) Decrease in temperature of water

(c) Less exposed surface area of water

(d) Adding common salt to water

Answer is a) Increase in temperature of water

Increase in temperature of water increases the kinetic energy of the water which will make more particles to attain enough energy to convert into the vapour state. This is how an increase in temperature favours evaporation.

On the other hand, the exposed surface is also responsible for the evaporation. Higher the exposed surface, higher will be the evaporation.

When common salt is added to water then the surface is occupied by the solvent as well as non-volatile solute particles.

This makes the escaping tendency of solvent particles decrease and thus the evaporation of water decreases. Hence options (b), (c) and (d) will decrease the evaporation of water.

10. In which of the following conditions, the distance between the molecules of hydrogen gas would increase?

(i) Increasing pressure on hydrogen contained in a closed container

(ii) Some hydrogen gas leaking out of the container

(iii) Increasing the volume of the container of hydrogen gas

(iv) Adding more hydrogen gas to the container without increasing the volume of the container

(a) (i) and (iii)

(b) (i) and (iv)

(c) (ii) and (iii)

(d) (ii) and (iv)

Answer is c) ii and iii

Explanation

• To increase the intermolecular interaction either volume of Hydrogen gas should be reduced or container volume should be increase.
• By increasing the pressure or by adding Hydrogen without increasing container volume inter-molecular interaction would decrease.
• Water under study was found to boil at 102°C at normal temperature and pressure.

Short Answer Questions

11. A sample of water under study was found to boil at 102°C at normal temperature and pressure. Is the water pure? Will this water freeze at 0°C? Comment.

The boiling point of pure water is 100 °C and the melting point is 0°C at 1 atmospheric pressure. Here the water boils at 102 °C hence it is not pure water and freezes at a temperature below 0°C.

12. A student heats a beaker containing ice and water. He measures the temperature of the content of the beaker as a function of time. Which of the following (Fig. 1.1) would correctly represent the result? Justify your choice.

Answer is d) because at the start of the experiment temperature of the mixture would be zero as water and ice will be in equilibrium. When students start heating initially latent heat will be utilised to melt the ice. Hence the temperature did not increase for a certain amount of time. When students heat the mixture further the temperature of the water increases gradually.

13. Fill in the blanks:

(a) Evaporation of a liquid at room temperature leads to a——— effect.

(b) At room temperature the forces of attraction between the particles of solid substances are———than those which exist in the gaseous state.

(c) The arrangement of particles is less ordered in the ——— state. However, there is no order in the ——— state.

(d) ——— is the change of solid state directly to vapour state without going through the ———state.

(e) The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called———.

• Liquid, gaseous
• Sublimation, liquid
• Evaporation

14. Match the physical quantities given in column A to their S I units given in column B:

(a) — (iii) The SI unit of pressure is the pascal (denoted by P).

(b) — (iv) The SI unit of temperature is -Kelvin (denoted by K).

(c) — (v) The SI unit of density is kilogram per cubic metre (kg/m 3 ).

(d) — (ii) The SI unit of mass is the kilogram (kg).

(e) — (i) The SI unit of volume is m 3 .

15. The non-SI and SI units of some physical quantities are given in column A and column B respectively. Match the units belonging to the same physical quantity:

(a) — (iv) Degree Celsius and kelvin are the units of temperature.

(b) — (iii) Centimetre and metre are the units of length.

(c) — (v) Gram per centimetre cube and kilogram per metre cube are the units of density.

(d) — (ii) Bar and pascal are the units of pressure.

(e) – (i) Milligram and kilogram are the units of mass.

16. ‘Osmosis is a special kind of diffusion’. Comment.

Diffusion in liquids and gases is the movement of particles from high concentration to low concentration. Osmosis is the movement of particles from the low concentration to high concentration through a semi-permeable membrane. This movement happens due to diffusion. Hence, osmosis is a special kind of diffusion.

17. Classify the following into osmosis/diffusion

(a) Swelling up of a raisin on keeping in water.

(b) Spreading of virus on sneezing.

(c) Earthworm dying on coming in contact with common salt.

(d) Shrinking of grapes kept in thick sugar syrup.

(e) Preserving pickles in salt.

(f) Spreading of smell of cake being baked throughout the house.

(g) Aquatic animals using oxygen dissolved in water during respiration

b) Diffusion

f) Diffusion

a) Swelling up of a raisin on keeping in water is osmosis because the concentration of solutes is more outside. Hence, water moves water from higher to lower concentrations through a semipermeable membrane, causing the raisin to swell.

b) Spreading the virus through sneezing is diffusion because the virus enters the air in tiny droplets. They remain suspended for a long time and move here and there in the air from higher to lower concentrations.

c) Earthworms die on coming in contact with common salt is osmosis because of variations in the concentration of water and solute. When salt is sprinkled on them, their skin gets dried, due to which their body shrinks, and they die.

d) The shrinking of grapes in thick sugar syrup is Osmosis because water will move down from higher to lower concentrations via a semipermeable membrane.

e) The Preserving of pickles in salt is Osmosis because salt helps to remove water from the cells and helps to preserve pickles.

f) The spreading of the smell of cake being baked throughout the house is Diffusion because the particles of cake move from a region of higher concentration to lower concentration through diffusion hence, producing the smell.

g) Aquatic animals using oxygen dissolved in water during respiration is osmosis because fish absorb oxygen from water (high concentration) through gills and skin (semipermeable membrane) to the lower concentration.

18. Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations.

Water as steam has more latent heat as compared to water as solid and liquid. Hence it causes severe burns while water as ice causes a cooling effect.

19. Alka was making tea in a kettle. Suddenly she felt intense heat from the puff of steam gushing out of the spout of the kettle. She wondered whether the temperature of the steam was higher than that of the water boiling in the kettle. Comment.

Steam and the temperature of water boiling in the kettle is the same. But the particles of steam have more energy in the form of latent heat of vaporisation than the particles of water. This energy is released when the steam condenses to water. Therefore, steam is hotter than boiling water.

20. A glass tumbler containing hot water is kept in the freezer compartment of a refrigerator (temperature < 0°C). If you could measure the temperature of the content of the tumbler, which of the following graphs (Fig.1.2) would correctly represent the change in its temperature as a function of time.

Graph (a) is the right answer because water will cool initially until its temperature reaches 0 °C. After reaching the freezing point (0 °C) temperature will remain constant until the water becomes ice. After that point temperature would decrease again.

21. Look at Fig. 1.3 and suggest in which of the vessels A,B, C or D the rate of evaporation will be the highest? Explain.

Answer is C because evaporation increases with an increase in the surface area. With an increase in wind speed particles of water vapour will move away hence the rate of evaporation will be the highest.

(a) Conversion of solid to vapour is called sublimation. Name the term used to denote the conversion of vapour to solid.

(b) Conversion of solid state to liquid state is called fusion; what is meant by latent heat of fusion?

used to denote the conversion of vapour to solid.

a) A deposition is the term used to denote the conversion of vapour to solid.

b) The amount of heat energy released or absorbed when a solid change to liquid at atmospheric pressure at its melting point is known as the latent heat of fusion.

Long Answer Questions

23. You are provided with a mixture of naphthalene and ammonium chloride by your teacher. Suggest an activity to separate them with well-labelled diagram.

Naphthalene is a non-polar compound which will not dissolve in water. Similarly, ammonium chloride is a polar compound which is soluble in water. Naphthalene is volatile in room temperature whereas ammonium chloride is volatile at high temperature.

The mixture of Naphthalene and ammonium chloride can be separated by decantation of aqueous mixture. Naphthalene remains undissolved in water and can be taken out in a funnel. The filtrate of ammonium chloride can be evaporated to obtain dry ammonium chloride.

24. It is a hot summer day, Priyanshi and Ali are wearing cotton and nylon clothes respectively. Who do you think would be more comfortable and why?

Hot summer leads to a lot of sweating. Cotton absorbs moisture whereas Nylon will not absorb the moisture as efficiently as cotton does. Hence cotton absorbs the sweat faster that Nylon does. Evaporation of moisture from the cotton cloth will give a cool feeling, especially when the wind blows. Hence, it can be concluded that Priyanshi will be more comfortable in summer days.

25. You want to wear your favourite shirt to a party, but the problem is that it is still wet after a wash. What steps would you take to dry it faster?

Drying of clothes is due to the process of evaporation hence the following steps should be taken to dry the shirt faster.

• Dry the shirt under a fan with high speed. With an increase in the speed of fan, water vapours will move away. This decreases water vapour in the surroundings which will increase the evaporation and the shirt gets dried faster.
• Spread the shirt on a hanger which will increase surface area. Increase in the surface area makes the shirt dry quickly.
• Dry the shirt in sunlight. Because of high-temperature water evaporates faster. Thus the shirt gets dried easily.
• Iron the shirt. Heat increases the speed of vaporization and evaporation. This dries the shirt faster.

26. Comment on the following statements:

(a) Evaporation produces cooling.

(b) Rate of evaporation of an aqueous solution decreases with increase in humidity.

(c) Sponge though compressible, is a solid.

a) When a liquid evaporates it takes latent heat from the object it touches. This will make the object cooler. Hence evaporation causes cooling.

b) When there is an increase in the humidity water vapour in the atmosphere will be more. Hence the atmosphere will not take water vapours easily which decreases the process of evaporation.

c) Sponge is a solid because it has definite shape and volume which does not change until you press it. It has minute pores in which air is filled. When you press it, air passes out through pores this makes it a compressible solid.

27. Why does the temperature of a substance remain constant during its melting point or boiling point?

The temperature of a substance remains constant during melting and boiling points till the completion of melting and boiling because of the latent heat of fusion used by the substances. Latent heat of fusion helps to overcome the force of attraction between particles of solid to change into a liquid when they melt. Hence temperature remains constant.

In the same way during the formation of vapours, latent heat helps solid substance to convert into a gaseous state. Hence temperature of a substance remains constant at boiling point.

Important Concepts of the NCERT Exemplar Class 9 Science Matter in Our Surroundings

• Physical nature of matter
• The matter is made up of particles
• How small are these particles of matter?
• Particles of matter are continuously moving
• Characteristics of particles of matter
• Particles of matter have space between them
• Particles of matter attract each other
• States of matter
• The liquid state
• The solid state
• The gaseous state
• Can matter change its state?
• Effect of change of temperature
• Effect of change of pressure
• Factors affecting evaporation
• How does evaporation cause cooling?

Students who study using the exemplar can prepare well and score excellent marks in examinations. For additional study materials, NCERT Solutions , sample papers and notes of all the subjects and classes, visit BYJU’S website or download BYJU’S – The Learning App.

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

Which of the following are matter ?

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

The mass per unit volume of a substance is called density (density = mass/volume).

Air, Exhaust from chimneys, cotton, water, honey, chalk, and iron.

→ Rigidity: It is the property of matter to resist the change of its shape. → Compressibility: It is the property of matter in which its volume is decreased by applying force. → Fluidity: It is the ability of matter to flow. → Filling a gas container: On filling a gas takes the shape of the container. → Shape: Having definite boundaries. → Kinetic Energy: It is the energy possessed by the particles of matter due to its motion. → Density: It is the ratio of mass with per unit volume.

(a)  The force of attraction between particles of gas is negligible. Because of this, particles of gas move in all directions. Thus, a gas fills the vessel completely in which it is kept.

(b)  Particles of gas move randomly in all directions at high speed. As a result, the particles hit each other and also hit the walls of the container with a force. Therefore, gas exerts pressure on the walls of the container.

(c)  A wooden table has fixed shape and fixed volume, which are the main characteristics of solid. Thus a wooden table should be called a solid. (d) Particles of the air have large spaces between them. On the other hand, wood has little space between its particles. Also, it is rigid. For this reason, we can easily move our hands in the air, but to do the same through a solid block of wood, we need a karate expert.

► 300 K = (300 - 273)°C

► 573 K = (573 - 273)°C

What is the physical state of water at:

(b)  Since water boils at this temperature thus it   can exist in both liquid and gaseous form. At this temperature, after getting the heat equal to the latent heat of vaporisation, water starts changing from liquid state to gaseous state.

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

(For Conversion Process we must know, Kelvin is an SI unit of temperature, where 0°C = 273 K approx.)

NCERT Solutions for Chapter 4 The Age of Industrialisation Class 10 History

Related chapters.

• Is Matter Around Us Pure
• Atoms and Molecules
• Structure of the Atom
• The Fundamental Unit of Life

Related Questions

• NCERT Revision Notes for Chapter 1 Matter in Our Surroundings Class 9 Science
• VSAQ for Ch 1 Matter in Our Surroundings Class 9 Science NCERT
• Assertion and Reason for Ch 1 Matter in Our Surroundings Class 9 Science

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CBSE MCQ for Class 9 Science Chapter 1 Matter In Our Surroundings Free PDF

The CBSE MCQ for Class 9 Science Chapter 1 Matter in our Surrounding are provided below, in detailed and free to download PDF format. The solutions are latest , comprehensive , confidence inspiring , with easy to understand explanation . To download NCERT Class 9 MCQ PDF for Free, just click ‘ Download pdf ’ button.

CBSE MCQ for Class 9 Science Chapter 1 Matter In Our Surroundings PDF

Checkout our mcqs for other chapters.

• CBSE MCQ for Class 9 Science Chapter 2 Is Matter Around Us Pure
• CBSE MCQ for Class 9 Science Chapter 3 Atoms and Molecules
• CBSE MCQ for Class 9 Science Chapter 4 Structure of the Atom
• CBSE MCQ for Class 9 Science Chapter 5 The Fundamental Unit of Life

How should I study for my upcoming exams?

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Practice MCQ Questions (Very Important)

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27 Facts About J.D. Vance, Trump’s Pick for V.P.

Mr. Vance spilled scores of details about his life in his coming-of-age memoir. We’ve collected the highlights.

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By Shawn McCreesh

Follow the latest news from the Republican National Convention .

J.D. Vance, Donald J. Trump’s choice for vice president, has not lived an unexamined life. Here are 27 things to know about him, drawn from his best-selling 2016 memoir, “Hillbilly Elegy,” and the many other things he has said or written since.

1. His name was not always James David Vance. At birth, it was James Donald Bowman. It changed to James David Hamel after his mother remarried, and then it changed one more time.

2. He longed for a role model. His father left when he was 6. “It was the saddest I had ever felt,” he wrote in his memoir. “Of all the things I hated about my childhood,” he wrote, “nothing compared to the revolving door of father figures.”

3. He had a fraught relationship with his mother, who was married five times. One of the most harrowing scenes in the book occurs when he’s a young child, in a car with his mother, who often lapsed into cycles of abuse. She sped up to “what seemed like a hundred miles per hour and told me that she was going to crash the car and kill us both,” he writes. After she slowed down, so she could reach in the back of the car to beat him, he leaped out of the car and escaped to the house of a neighbor, who called the police.

4. He was raised by blue-dog Democrats. He spent much of his childhood with his grandfather and grandmother — papaw and mamaw, in his hillbilly patois. He described his mamaw’s “affinity for Bill Clinton” and wrote about how his papaw swayed from the Democrats only once, to vote for Ronald Reagan. “The people who raised me,” he said in one interview, “were classic blue-dog Democrats, union Democrats, right? They loved their country, they were socially conservative.”

5. As a teenager, he loved Black Sabbath, Eric Clapton and Led Zeppelin. But then his biological father, who was deeply religious, re-entered his life. “When we first reconnected, he made it clear that he didn’t care for my taste in classic rock, especially Led Zeppelin,” he wrote. “He just advised that I listened to Christian rock instead.”

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