Important Questions for CBSE Class 9 Science Matter in Our Surroundings

Science can be challenging to learn, and some concepts are difficult to comprehend. However, students have to understand the concepts of physics, chemistry, and biology in-depth to appreciate the world around them, and also to choose their  streams better. Besides, Matter in Our Surrounding chapter is one of the introductory chapters in Science. It covers essential topics such as matter, characteristics of matter, nature of matter, and gas properties. These topics carry significant weightage in the Science syllabus. Students can find the concepts, theories, and NCERT solutions with numerous solved examples on our Extramarks official website. 

To score good marks, students must practise as many questions as possible  and evaluate their preparation strategy to stand head and shoulders above the rest. At Extramarks, we understand the importance of solving questions and practice exercises to step up their preparation. Extramarks has  a repository of questions from the NCERT textbook, NCERT exemplar, and other reference books. Furthermore, it also has questions from past years’ exam papers. Students can solve  important questions in Class 9 Science Chapter 1 to lay a strong foundation. . 

Our experienced subject matter experts offer appropriate concise  answers to all the questions. It makes it easy to comprehend and understand the concepts. In addition, students can register on the Extramarks website and access our complete set of Important Questions Class 9 Science Chapter 1. 

Students may  refer to other study material on our Extramarks websites, such as NCERT solutions, CBSE revision notes, past year questions papers, and NCERT books. Therefore, students need not look elsewhere for any reference material to supplement their studies. Extramarks provides  one stop solution to all your problems. To enjoy the maximum benefit of these resources, students just need to register themselves at Extramarks official website and stay ahead of the pack. 

Get Access to CBSE Class 9 Science Important Questions 2022-23 with Solutions

Also, get access to CBSE Class 9 Science Important Questions for other chapters too:

CBSE Class 9 Science Chapter 1 Question Answer

Q1. Divers can cut through the water in a swimming pool. What property of matter does  this observation prove?

Answer:  The driver’s ability to cut through water in a swimming pool  shows that water particles are  held together by weak forces and can be separated by applying an external force.

Q2. Discuss the following: rigidity and compressibility, fluidity, filling gas containers, shape, kinetic energy, and density.

Answer: Rigidity – The property of matter to retain its form when external forces are applied to them is called rigidity. This property is found in solids.

Compressibility – This property allows matter to be compressed when pressure is applied to it. This property is present in some liquids as well as all gases.

Fluidity – Matter’s ability to change shape and flow when external forces are applied is called fluidity. This property is present in both liquids and gases.

Filling a gas container, It is possible to fill large volumes of gas in a smaller container, making it more convenient and cost-effective for transport.

Shape – Solid objects must have well-defined shapes, while liquids can take any shape depending on what container they are kept in. Gases don’t have any form.

Kinetic energy – The particles in a matter are constantly in motion and therefore have kinetic energy. The kinetic energy of solids will be the lowest because they have the most movement. Gas particles have the free t movement and therefore have the highest kinetic energies. For different types of matter, the order of kinetic energy is solid, liquid and gas.

Density – The density of any substance can be described as mass per unit volume. Density = mass/volume

Q3. Why do people wear cotton clothes  in summer?

Answer: People wear cotton clothes in summer because  cotton is an excellent water absorbent , it absorbs sweat and allows  fast evaporation. Because sweat evaporates heat, it makes us feel relaxed on hot summer days.  That’s  why people prefer wearing  cotton clothes   during the summer season.

Q4. Differentiate between the states of matter. 

Answer: 

Q5. Gases can be substantially compressed but liquids cannot be compressed much. Why?

Answer: Because gases have significant gaps between their particles, they are easy to compress. Liquids, however, have tiny spaces between their particles. Liquids are therefore not compressible.

Q6. What are fractional distillation and distillation? What is the fundamental property that distinguishes these two methods?

Answer: Distillation is used to separate the components of a mixture that contains two liquids. They have different boiling points, and each liquid boils without being decomposed.

Fractional distillation can be used to separate the components of a mixture that contains more than two liquids with a boiling point difference of less than 25K. A fundamental property separates these two methods:

Distillation can be used to separate components with significant differences in boiling points. Fraction distillation can be used when there is a  negligible difference in boiling points.

Q7. We observe no change in volume of water  when we dissolve a specific amount of salt/sugar into a given volume. This observation illustrates which characteristic of matter?

Answer:  The characteristics of matter as described by the observation are as follows:

(i) Matter is composed of tiny particles.

(iii) Matter particles have spaces between them.

When salt or sugar is dissolved in water, it enters the spaces between water particles. This is why the volume of water does not change.

Q8. Identify the condition which will increase the evaporation of water?

1. Increase in the temperature of the water
2. Decrease in the temperature of the water
3. Less exposed to the surface area of water
4. Adding common salt to  water

Answer: a) Increase in the temperature of the water.

Explanation: Increasing the temperature will offer more heat energy to the water molecules. In addition, more heat energy will lead to an increased rate of evaporation. Further, the water’s evaporation rate is directly proportional to the temperature of the water, and it is exposed to the surface area. Besides the other conditions, decreasing temperature and reducing exposed surface areas will reduce the water evaporation rate. 

Q9. Fill in the blanks: – 

1. a) Evaporation of  liquid at room temperature leads to a ______ effect. 
2. b) At room temperature, the forces of attraction between the particles of a solid substance are ____ than those in the gaseous state. 
3. c) ______ is the change of gaseous state directly to solid state without going through the _____ state. 
4. d) The basic arrangement of particles is less than ordered in the ____ state. However, there is no order in the _____ state. 
5. e) The phenomenon of the state of change of a liquid into the gaseous state at any temperature its boiling point is known as ______

Answer: a) cooling

1. b) stronger
2. c) liquid, gaseous
3. d) sublimation, liquid
4. e) evaporation

Q10. “Osmosis is a special kind of diffusion”. Explain

Answer: The processes of diffusion and osmosis have much in common. Both phenomena involve particles moving to lower concentrations from higher concentrations. In the case of osmosis, however, the movement is of solvent particles from one area to another through a semipermeable membrane.

Q11. The following can be classified as osmosis/diffusion.

(a) The swelling of a raisin when you keep it in water.

Ans. Osmosis: The water that enters the raisin is affected by osmosis. This happens because the solution outside the raisin contains higher concentration water molecules, and the outer membrane acts as a semipermeable membrane. The raisin expands when it is kept in water.

(b) Spread of the virus through sneezing.

Ans: Diffusion. Diffusion is the process by which microscopic virus particles are released into the air.

(c) Earthworms die when they come in contact with salt.

Ans: Osmosis. Earthworms die when they come in contact with standard sodium. This is because common salt contains a lower concentration than earthworm’s body.

(d) Grapes are shrivelled in thick sugar syrup.

Ans: Osmosis. Grapes kept in thick sugar syrup shrink because the syrup has a lower concentration of water molecules than the grapes. The water molecules are released from grapes, where the outer membrane of the grape cell acts as a semipermeable membrane.

(e) Salt preservation of pickles

Ans. Osmosis: Pickles are preserved with salt because pickles contain high natural water levels. Salt protects vegetables and fruits from oxidation because it absorbs excess moisture through osmosis.

(f) The smell of freshly baked cake permeates  the entire house.

Ans: Diffusion. The diffusion of particles in the air spreads  the aroma  of baking cakes.

(g) Aquatic animals use oxygen dissolved in water for respiration. 

Answer: Diffusion. The oxygen from the atmosphere diffuses into the water, and aquatic animals use this oxygen during respiration.

Q12. Which one of these matters? Chair, air; love; smell; hate; almonds; thought. Cold, cold drinks. The scent of perfume.

Answer: Matter can be anything that occupies space with some mass. There are three types of matter: Solid, Liquid, and Gas. These three states can be used to determine the type of matter..

Almonds and chairs are solid states of matter because they have a fixed shape. Because cold drinks have no fixed shape , they are liquid. The smell of perfume and air has gaseous particles that are not subject to movement, so they can also be considered gaseous states of matter.

Although Love, Hate, Cold, Smell, and Thought have no mass or occupy space, humans feel these emotions and sensations, so they cannot be considered as  matter.

Q13. These observations are to be taken seriously.

1. Naphthalene balls vanish with time, leaving no solid.

Ans. This phenomenon can be explained by sublimation, which means that a solid is converted directly into a gaseous form without becoming liquid. Sublimation is a process that occurs at room temperature. Therefore naphthalene balls can disappear after a time leaving no trace. 

1. It is possible to smell the perfume from several metres.

Ans: Gaseous particles possess meagre internuclear forces, which allow them to move very freely and have high kinetic energy. Because perfume particles diffuse into the air, the molecules of the perfume will react with the environment. This allows us to smell the perfume even from several metres away.

Q14. What are the characteristics of particles of matter?

Answer: (a) Particles of  matter particles attract one another.

(i) The force between particles of matter keeps them bonded together. The attraction force between solid particles is the greatest, while between liquid particles is moderate, and between gas particles is the lowest.

(iii) Our hand can be moved quickly through the air because of the low force of attraction between gas particles. We must exert force to move our hands in water, but not from solids like wood.

(iii) This is because the force between gas particles is negligible in liquid but more significant in solid.

(iv) The attraction force between particles of solid, liquid, and gas can be organised in decreasing order as follows: solid, liquid, and gas

(b) Particles of  matter  have space between them.

(i) Gas can easily be compressed because of the space between its particles.

(iii) Sugar particles dissolve in water. This happens because sugar particles are adjusted in the space between water particles. You will also notice that no water level increases when adding one teaspoon or more sugar to a glass. This is because particles are adjusted in the space between each water particle.

Q15. Water at room temperature can be considered a liquid. Give reasons.

Answer: Water at room temperature can be considered a liquid since it has fluidity, a definite volume and no definite form.

Q16. We can smell the hot, smoky food from several metres away. It isn’t true if the food is cold. Explain.

Answer: The vapours from hot and steamy food are released when it is still warm. These particles easily mix with air particles because the particle’s kinetic energy is exceptionally high in the vapour state. They can reach us from several  metres away. The vapours that are released when food is cold will be much lower. Their kinetic energy is also quite less. . These conditions require one to be very close to the food to get a good smell.

Q17. What is the purpose of a gas filling up a vessel?

Answer: This is due to the rapid diffusion of particles in a gas. There are a lot of empty spaces and voids in a gaseous state. The particles of a gas will move very quickly. They quickly fill the container in which they are kept. The volume of the gas will be the same as the vessel.

Q18. How does water in an earthen pot (matka) cool down during summer?

Answer: Because the earthen pot is porous and has tiny  pores, the water inside it  remains cool  in summer. . The water temperature inside the pot is much lower than the outside temperature This causes water to escape from the pot’s surface and evaporates,  so the water remains cool. .

Q19. Liquids have a lower density than solids. You must have noticed that ice floats on water. Reason why.

Answer: Density is the mass of a substance per unit volume. (density = weight/volume). The density of a substance decreases as it grows in volume. Although ice is solid, there are large amounts of space between its particles. These spaces are much larger than the space between water particles. The ice volume is, therefore, larger than the volume of water. Therefore, ice has a lower density than water.  Ice can float on substances with a lower density than water. Hence, ice floats on water.

Q20. Which of the following phenomena would cause the temperature to rise?

(a) Diffusion and evaporation of gases.

(b) Evaporation and compression of gases, solubility

(c) Evaporation and diffusion of gases, expansion

(d) Evaporation and solubility, diffusion, compression

Answer: (c) Evaporation and diffusion of gases, expansion

Explanation: Because they have kinetic energy, matter particles are constantly moving. Diffusion is when matter particles are mixed at high temperatures. Evaporation is the conversion of liquid into vapour. As temperature increases, molecules vibrate and move so fast that they escape to the atmosphere as vapours. Temperature increases cause molecules to move faster, resulting in  expansion of gas.

Q21. Seema visited the Natural Gas Compressing Unit to discover that the gas can be liquefied at specific temperatures and pressures. She shared her experience with her friends but got confused. Help her identify the right set of conditions.

(a) Low temperature and low pressure

(b) High Temperature, Low Pressure

(c) Low temperature and high-pressure

(d) High temperature and high-pressure

Answer: (c) Low temperature and high-pressure

Explanation: 

Low temperature and high pressure are required to compress gas into a liquid. There is a lot of space between the gas particles. When pressure is applied, the gas particles get closer and start to attract one another to form a liquid. Gas is compressed and generates a lot of heat. It is, therefore, necessary to cool it. Cooling reduces the temperature and aids in liquefying compressed gas.

Q22. The “cooling off” causes the water in earthen pots to cool down during summer.

(a) Diffusion

(b) Transpiration

(c) Osmosis

(d) Evaporation

Answer: (d) Evaporation

Explanation: The temperature of the immediate environment is reduced by the evaporation of water through pores in an earthen pot. This results in after a while; the water will cool down. Transpiration is the movement of water through plants and its evaporation through its aerial components. Diffusion refers to the movement of a substance in an area with a higher concentration to one of lower concentrations. Semipermeable membranes are used to prevent solvent molecules from passing through semipermeable membranes. It is also known as osmosis, which converts a solution into a concentrated one.

Q23. Select the correct statement from the following:

(a) Sublimation is the conversion of solids into vapours without going through the liquid.

(b) Vaporisation is the conversion of vapours to solid without going through the liquid state.

(c) The conversion of vapours to solid without passing through the liquid is known as freezing.

(d) Sublimation is the conversion of solid to liquid.

Answer: (a) Sublimation is the conversion of solids into vapours without going through the liquid.

Explanation: 

Sublimation refers to the process by which a solid becomes vaporous without going through its liquid state. Vaporisation refers to a phase change from liquid to vapours. Freezing is converting liquid to solid at a substance’s freezing temperature.

Q24. It is your favourite shirt that you want to wear to a party. However, it is still damp after washing. Explain the process of evaporation using different methods to dry the  damp shirt.

Answer: The process of evaporation causes clothes to dry faster. Follow these steps to dry your shirt quickly.

1. Turn on the fan on  high-speed  to dry  the shirt underneath.  As the speed of the fan increases,  water from the damp shirt reduces due to evaporation. . This reduces the amount of water vapour in the surrounding, speeding up the process of    evaporation. The shirt will dry faster.
2. The shirt will dry faster if spread on a clothesline.. The shirt will dry faster if it has a larger surface area.
3. The shirt can  be dried in the sun. High temperatures increase the kinetic energy required to convert water vapour to vapour. This will accelerate the evaporation process, and the shirt will dry quickly.
4. Iron your shirt. The speed of evaporation or evaporation is increased by heat. This will allow the shirt to dry faster.

Q25. What is the reason why the temperature of a substance remains constant at its melting point or boiling point?

Answer: Latent heat of fusion is why a substance’s temperature remains constant throughout melting and boiling and continues to rise after the end of boiling and melting. Latent heat from fusion is a force that allows solid particles to melt into liquids. Hence temperature remains constant. The same happens when vapours form. Latent heat aids solid substances from becoming gaseous. The temperature of a substance remains constant even at its boiling point.

Q26. Fill in the blanks. 

1. a) Evaporation of a liquid at normal temperature will lead to a  _____ effect. 
2. b) At room temperature, the forces of attraction between the particles of solid substances are ____ than those in the gaseous state. 
3. c) The arrangement of particles will be less in order in the ____ state. Therefore, there is no order in the_______ state. 
4. d) ____ is the change of gaseous state which directly converts to solid-state without going through the _____ state. 
5. e) The phenomenon of change of a liquid into the gaseous state at any room temperature below its boiling point will be known as _____

Answer: a) cooling

1. b) stronger
2. c) liquid, gaseous
3. d) Sublimation, liquid 
4. e) evaporation

Q27. What are the conditions for “something” to be called matter?

Answer: The main conditions for something to matter are should:

(a) occupy space and

(b) have mass

Q28. Name two processes that provide the most evidence of the moving particles in matter.

Answer: Brownian motion and diffusion are the best examples of random motion of particles within matter.

Q29. What single term can describe copper sulphate mixed with water in a cup?

Answer: Diffusion is the singular term that describes the mixture of copper sulphate and water in a cup..

Q30. The density of gases can change with: 

1. a) temperature and volume
2. b) pressure only 
3. c) temperature only 
4. d) pressure and temperature 

Answer: b) Pressure only 

Q31. What will happen to the volume of the solution when a small amount of sugar is dissolved in it?

1. Volume will increase
2. The volume will decrease
3. Volume first increases, then decrease
4. No change in volume

Answer: 2) Volume will increase

Q32. When a liquid starts boiling, the further heat energy which is supplied- 

1. It is lost due to the surroundings as such
2. May increase the temperature of the liquid
3. Increase the kinetic energy of the liquid
4. It is absorbed as latent heat of evaporation by the liquid. 

Answer: d) Is absorbed as latent heat of evaporation by the liquid. 

Key Topics Covered in Chapter 1 Science Class 9 Important Questions

This chapter requires proper comprehension of the topics  and the complex concepts explained in the chapter, and students must recall and understand new concepts with logical reasoning of  the wide range of identities they have read so far. 

Matter in Our Surrounding 

All the matter around us comprises pencils, pens, tables, food and clothing. The substances and materials that make up matter. Also, the matter is anything that occupies space and can be detected by our senses.

Physical nature of matter

Physical properties refer to the physical features and characteristics of matter. They can be observed or measured and are not affected by their form or composition. It doesn’t depend on the amount of matter present in the environment. It includes colour, appearance, smell and melting point.

Characteristics of particles of matter

Particles of matter have intermolecular spaces and are in continuous motion. It experiences forces from one another. 

Following are the characteristics of particles of matter: 

• Spaces between particles of matter allow for the solubility of substances in other substances. Because sugar particles are trapped between the particles, it is unlikely that water levels will rise when sugar is dissolved in water.
• Matter particles are constantly in motion. They show random movements because of the kinetic energy that they possess. A temperature rise can also increase the kinetic energy, which causes particles to move more vigorously.
• Interparticle forces of attraction are what attract matter particles to each other. To break a substance, we must overcome this force.

States of matter

The state of matter is classified into three forms: solids, liquids, and gases. The table below shows the difference between these three states of matter: 

Can matter change its state?

Temperatures rise, and particles’ kinetic energy increases, making them move with more energy. The attraction force between particles also decreases. They begin to move freely and break away from their original positions. Additionally, matter’s condition changes and solids alter their phase. This results in liquids. Liquids also undergo phase changes to become a gas, similar to liquids.

• The melting point is defined as the temperature at which solid metals turn liquid under atmospheric pressure. During high melting points, the liquid and solid phases are in equilibrium.
• The boiling point of a liquid is defined as the temperature where a liquid’s vapour pressure equals atmospheric pressure.
• Sublimation is the process by which a substance that was in a solid phase becomes a gaseous phase. Sublimation is a process when a substance in a solid phase changes into a liquid phase.
• Pressure changes: As pressure is applied, the interparticle spacing between matter particles decreases. A solid can be transformed into a liquid by applying pressure and decreasing temperature.

Vaporisation

Water  boils when it  is sufficiently hot. Boiling water can create bubbles of water vapour. These bubbles form when liquid water particles gain enough energy to overcome their attraction and transform into a gaseous state. The bubbles release the steam from the pot as they rise through the water. Vaporisation is the process by which liquids boil and become gas. The boiling point of a liquid is the temperature at which liquids boil.

Condensation

Mirrors may become  foggy   when you take a hot bath in a  bathroom. This may make you wonder what causes it. Hot water evaporates from the shower and comes into contact with more excellent surfaces like the mirror. This causes it to lose energy and cool down. The forces of attraction between the cooler water particles are no longer strong enough to counter them. They combine and form droplets on the mirror. . The process by which gas transforms into liquid is defined as condensation.

Evaporation

It refers to changing liquids into vapour at temperatures below their boiling point. Evaporation can also be described as a surface phenomenon.

These are the main factors that influence evaporation.

Evaporation is affected by an increase in surface area.

• Evaporation can produce a cooling effect.
• The rate of evaporation will increase with an increase in wind speed.
• The rate of evaporation increases with a decrease in humidity
• Temperature increases can increase the rate at which evaporation occurs.

Applications of Evaporative cooling

• Our bodies sweat to cool themselves. Evaporation is the essence of sweat. The process of water vaporising from the body results in energy loss and a decrease in body temperature.
• Cotton clothes are popular in the summer. Because cotton clothes  absorb  water, it allows sweat to contact more air, allowing for more evaporation. Cotton clothes make us feel cool during the hot summer season..
• To keep water cool, it is kept in earthen pots. Like cotton cloth’s pores, the pores in an earthen pot allow for greater evaporation.
• On hot and dry days, an air cooler will be more efficient. Evaporative cooling is the basic principle of how an air cooler works. If it is hot and dry, the humidity is low, and the temperature is high, the evaporation rate will be higher. Water is converted into vapour by the water taking energy from the air. This makes the air cool.

Further, students can refer to Class 9 science Chapter 1 critical questions and improve their preparation for the upcoming examination. 

Benefits of Solving Important Questions Class 9 Science Chapter 1

Many students face difficulty solving science questions and doing the class assignments and find it challenging to understand the key concepts and theories which require regular study with notes and revision work.  . The best way to overcome this problem is to practice Important Questions Class 9 Science Chapter 1. Students can improve their skills in this subject by solving these questions and strengthening their understanding of the concept. Students can access our website’s comprehensive set of matter in our surroundings extra questions.

Some of the  benefits of frequently solving NCERT textbook and NCERT exemplar questions for Class 9 Science: 

• Important questions in class 9 Science chapter 1 are selected under the guidance of  expert faculty   with years of experience,while adhering to the guidelines laid by CBSE.
• The questions mentioned in the list will likely come in the annual exam because CBSE picks questions from NCERT books which Extramarks experts diligently follow while preparing answers. Therefore, students will be able to perform better and score high grades in their exams.. 
• Extra Questions on Matter in Our Surroundings Class 9 have solutions in a detailed manner. Students can rely on authentic and concise answers and they can study from it without having to look elsewhere for any assistance. This is true for all subjects.  
• To clear the competitive exams, students will be able to prepare themselves with the help of these questions. NCERT books are the best for such exams and the educational resources provided by Extramarks are extremely useful.
• Students will be able to develop analytical skills by solving these questions. 
• The list of Important Questions Class 9 Science Chapter 1 is from  the latest CBSE syllabus and consists of essential questions from NCERT books which CBSE recommends. 
• By solving the NCERT textbook and NCERT exemplar questions for class 9, Science students will be able to develop confidence in their subject since subject experts  of the CBSE board have prepared these questions. 
• Science class 9 chapter 1 important questions are very important in solving the subject; students will be able to enhance  their  learning curve and will master  the subject without getting stressed or anxious. 

Extramarks is one of the leading online learning platforms offering comprehensive learning solutions for students from class 1 and class 12. In addition to this, Extramarks also  provides  study material and revision notes. It is available on the website. Besides, students can click on the links given below to access some of the essential resources:

• NCERT books
• CBSE Revision Notes
• CBSE syllabus
• CBSE sample papers
• CBSE previous year’s question papers
• Important formulas 
• CBSE extra questions