cbse class 9 chemistry chapter 2 case study questions

myCBSEguide

• Class 9 Science Case...

Class 9 Science Case Study Questions

Table of Contents

myCBSEguide App

Download the app to get CBSE Sample Papers 2023-24, NCERT Solutions (Revised), Most Important Questions, Previous Year Question Bank, Mock Tests, and Detailed Notes.

If you are wondering how to solve class 9 science case study questions, then myCBSEguide is the best platform to choose. With the help of our well-trained and experienced faculty, we provide solved examples and detailed explanations for the recently added Class 9 Science case study questions.

You can find a wide range of solved case studies on myCBSEguide, covering various topics and concepts. Class 9 Science case studies are designed to help you understand the application of various concepts in real-life situations.

The rationale behind Science

Science is crucial for Class 9 students’ cognitive, emotional, and psychomotor development. It encourages curiosity, inventiveness, objectivity, and aesthetic sense.

In the upper primary stage, students should be given a variety of opportunities to engage with scientific processes such as observing, recording observations, drawing, tabulating, plotting graphs, and so on, whereas in the secondary stage, abstraction and quantitative reasoning should take a more prominent role in science teaching and learning. As a result, the concept of atoms and molecules as matter’s building units, as well as Newton’s law of gravitation, emerges.

Science is important because it allows Class 9 Science students to understand the world around us. It helps to find out how things work and to find solutions to problems at the Class 9 Science level. Science is also a source of enjoyment for many people. It can be a hobby, a career, or a source of intellectual stimulation.

Case study questions in Class 9 Science

The inclusion of case study questions in Class 9 science CBSE is a great way to engage students in critical thinking and problem-solving. By working through real-world scenarios, Class 9 Science students will be better prepared to tackle challenges they may face in their future studies and careers. Class 9 Science Case study questions also promote higher-order thinking skills, such as analysis and synthesis. In addition, case study questions can help to foster creativity and innovation in students. As per the recent pattern of the Class 9 Science examination, a few questions based on case studies/passages will be included in the CBSE Class 9 Science Paper. There will be a paragraph presented, followed by questions based on it.

Examples of Class 9 science class case study questions

Class 9 science case study questions have been prepared by myCBSEguide’s qualified teachers. Class 9 case study questions are meant to evaluate students’ knowledge and comprehension of the material. They are not intended to be difficult, but they will require you to think critically about the material. We hope you find Class 9 science case study questions beneficial and that they assist you in your exam preparation.

The following are a few examples of Class 9 science case study questions.

Class 9 science case study question 1

• due to its high compressibility
• large volumes of a gas can be compressed into a small cylinder
• transported easily
• all of these
• shape, volume
• volume, shape
• shape, size
• size, shape
• the presence of dissolved carbon dioxide in water
• the presence of dissolved oxygen in the water
• the presence of dissolved Nitrogen in the water
• liquid particles move freely
• liquid have greater space between each other
• both (a) and (b)
• none of these
• Only gases behave like fluids
• Gases and solids behave like fluids
• Gases and liquids behave like fluids
• Only liquids are fluids

Answer Key:

• (d) all of these
• (a) shape, volume
• (b) the presence of dissolved oxygen in the water
• (c) both (a) and (b)
• (c) Gases and liquids behave like fluids

Class 9 science case study question 2

• 12/32 times
• 18 g of O 2
• 18 g of CO 2
• 18 g of CH 4
• 1 g of CO 2
• 1 g of CH 4 CH 4
• 2 moles of H2O
• 20 moles of water
• 6.022  ×  1023 molecules of water
• 1.2044  ×  1025 molecules of water
• (I) and (IV)
• (II) and (III)
• (II) and (IV)
• Sulphate molecule
• Ozone molecule
• Phosphorus molecule
• Methane molecule
• (c) 8/3 times
• (d) 18g of CH ​​​​​4
• (c) 1g of H ​​​​​​2
• (d) (II) and (IV)
• (c) phosphorus molecule

Class 9 science case study question 3

• collenchyma
• chlorenchyma
• It performs photosynthesis
• It helps the aquatic plant to float
• It provides mechanical support
• Sclerenchyma
• Collenchyma
• Epithelial tissue
• Parenchyma tissues have intercellular spaces.
• Collenchymatous tissues are irregularly thickened at corners.
• Apical and intercalary meristems are permanent tissues.
• Meristematic tissues, in its early stage, lack vacuoles, muscles
• (I) and (II)
• (III) and (I)
• Transpiration
• Provides mechanical support
• Provides strength to the plant parts
• None of these
• (a) Collenchyma
• (b) help aquatic plant to float
• (b) Sclerenchyma
• (d) Only (III)
• (c) provide strength to plant parts

Cracking Class 9 Science Case Study Questions

There is no one definitive answer to Class 9 Science case study questions. Every case study is unique and will necessitate a unique strategy. There are, nevertheless, certain general guidelines to follow while answering case study questions.

• To begin, double-check that you understand the Class 9 science case study questions. Make sure you understand what is being asked by reading it carefully. If you’re unclear, seek clarification from your teacher or tutor.
• It’s critical to read the Class 9 Science case study material thoroughly once you’ve grasped the question. This will provide you with a thorough understanding of the problem as well as the various potential solutions.
• Brainstorming potential solutions with classmates or other students might also be beneficial. This might provide you with multiple viewpoints on the situation and assist you in determining the best solution.
• Finally, make sure your answer is presented simply and concisely. Make sure you clarify your rationale and back up your claim with evidence.

A look at the Class 9 Science Syllabus

The CBSE class 9 science syllabus provides a strong foundation for students who want to pursue a career in science. The topics are chosen in such a way that they build on the concepts learned in the previous classes and provide a strong foundation for further studies in science. The table below lists the topics covered in the Class 9 Science syllabus of the Central Board of Secondary Education (CBSE). As can be seen, the Class 9 science syllabus is divided into three sections: Physics, Chemistry and Biology. Each section contains a number of topics that Class 9 science students must study during the course.

CBSE Class 9 Science (Code No. 086)

Theme: Materials Unit I: Matter-Nature and Behaviour Definition of matter; solid, liquid and gas; characteristics – shape, volume, density; change of state-melting (absorption of heat), freezing, evaporation (cooling by evaporation), condensation, sublimation. Nature of matter:  Elements, compounds and mixtures. Heterogeneous and homogenous mixtures, colloids and suspensions. Particle nature and their basic units:  Atoms and molecules, Law of constant proportions, Atomic and molecular masses. Mole concept: Relationship of mole to mass of the particles and numbers. Structure of atoms:  Electrons, protons and neutrons, valency, the chemical formula of common compounds. Isotopes and Isobars.

Theme: The World of the Living Unit II: Organization in the Living World Cell – Basic Unit of life:  Cell as a basic unit of life; prokaryotic and eukaryotic cells, multicellular organisms; cell membrane and cell wall, cell organelles and cell inclusions; chloroplast, mitochondria, vacuoles, endoplasmic reticulum, Golgi apparatus; nucleus, chromosomes – basic structure, number. Tissues, Organs, Organ System, Organism: Structure and functions of animal and plant tissues (only four types of tissues in animals; Meristematic and Permanent tissues in plants).

Theme: Moving Things, People and Ideas Unit III: Motion, Force and Work Motion:  Distance and displacement, velocity; uniform and non-uniform motion along a straight line; acceleration, distance-time and velocity-time graphs for uniform motion and uniformly accelerated motion, derivation of equations of motion by graphical method; elementary idea of uniform circular motion. Force and Newton’s laws:  Force and Motion, Newton’s Laws of Motion, Action and Reaction forces, Inertia of a body, Inertia and mass, Momentum, Force and Acceleration. Elementary idea of conservation of Momentum. Gravitation:  Gravitation; Universal Law of Gravitation, Force of Gravitation of the earth (gravity), Acceleration due to Gravity; Mass and Weight; Free fall. Floatation:  Thrust and Pressure. Archimedes’ Principle; Buoyancy. Work, energy and power:  Work done by a Force, Energy, power; Kinetic and Potential energy; Law of conservation of energy. Sound:  Nature of sound and its propagation in various media, speed of sound, range of hearing in humans; ultrasound; reflection of sound; echo.

Theme: Food Unit IV: Food Production Plant and animal breeding and selection for quality improvement and management; Use of fertilizers and manures; Protection from pests and diseases; Organic farming.

PRESCRIBED BOOKS:

• Science-Textbook for class IX-NCERT Publication
• Assessment of Practical Skills in Science-Class IX – CBSE Publication
• Laboratory Manual-Science-Class IX, NCERT Publication
• Exemplar Problems Class IX – NCERT Publication

myCBSEguide: A true helper

There are numerous advantages to using myCBSEguide to achieve the highest results in Class 9 Science.

• myCBSEguide offers high-quality study materials that cover all of the topics in the Class 9 Science curriculum.
• myCBSEguide provides practice questions and mock examinations to assist students in the best possible preparation for their exams.
• On our myCBSEguide app, you’ll find a variety of solved Class 9 Science case study questions covering a variety of topics and concepts. These case studies are intended to help you understand how certain principles are applied in real-world settings
• myCBSEguide is that the study material and practice problems are developed by a team of specialists who are always accessible to assist students with any questions they may have. As a result, students may be confident that they will receive the finest possible assistance and support when studying for their exams.

So, if you’re seeking the most effective strategy to study for your Class 9 Science examinations, myCBSEguide is the place to go!

Test Generator

Create question paper PDF and online tests with your own name & logo in minutes.

Question Bank, Mock Tests, Exam Papers, NCERT Solutions, Sample Papers, Notes

Related Posts

• Competency Based Learning in CBSE Schools
• Class 11 Physical Education Case Study Questions
• Class 11 Sociology Case Study Questions
• Class 12 Applied Mathematics Case Study Questions
• Class 11 Applied Mathematics Case Study Questions
• Class 11 Mathematics Case Study Questions
• Class 11 Biology Case Study Questions
• Class 12 Physical Education Case Study Questions

Leave a Comment

Save my name, email, and website in this browser for the next time I comment.

Gurukul of Excellence

Classes for Physics, Chemistry and Mathematics by IITians

Join our Telegram Channel for Free PDF Download

Case Study and Passage Based Questions for Class 9 Science Chapter 2 Is Matter Around Us Pure?

• Last modified on: 2 years ago
• Reading Time: 4 Minutes

Case Study Questions:

Question 1:

Akshita wants to separate the mixture of dyes constituting a sample of ink. She marked a line by the ink on the filter paper and placed the filter paper in a glass containing water as shown in figure. The filter paper was removed when the water moved near the top of the filter paper.

(i) Identify the technique used by the Akshita. (a) Sedimentation (b) Filtration (c) Chromatography (d) Distillation

(ii) What would you expect to see, if the ink contains three different coloured components? (a) We will not see any band on the filter paper. (b) We would see three bands on the filter paper at various lengths. (c) We would see infinite bands on the filter paper. (d) We would see single band on the filter paper.

(iii) An application where you can use this technique is: (a) To separate salt from sand (b) To separate wheat from husk (c) To separate oil from water (d) To separate drugs from blood.

(iv) The above process is used for the separation of : (a) insoluble substances (b) single solute that dissolves in soluble solvent. (c) solutes that dissolve in the same solvent. (d) solutes that dissolve in the different solvents.

(v) What is chromatography ? (a) It is an agricultural method to separate grains (b) A method to separate magnetic impurities from non-magnetic impurities (c) The process of separating the suspended particles of an insoluble substance (d) Method of separating and identifying various components in a mixture, which are present in small trace quantities.

You may also like:

Case Study and Passage Based Questions for Class 9 Science Chapter 3 Atoms and Molecules

Last modified on:2 years agoReading Time:5MinutesCase Study Questions for Class 9 Science Chapter 3 Atoms and Molecules 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…

Case Study and Passage Based Questions for Class 9 Science Chapter 4 Structure of Atom

Last modified on:2 years agoReading Time:4MinutesCase Study Questions for Class 9 Science Chapter 4 Structure of Atom 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…

Case Study and Passage Based Questions for Class 9 Science Chapter 10 Gravitation

Last modified on:2 years agoReading Time:4MinutesCase Study Questions for Class 9 Science Chapter 10 Gravitation 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 questions based…

Case Study and Passage Based Questions for Class 9 Science Chapter 11 Work and Energy

Last modified on:2 years agoReading Time:4MinutesCase Study Questions for Class 9 Science Chapter 11 Work and Energy 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…

Case Study and Passage Based Questions for Class 9 Science Chapter 13 Why Do We Fall Ill

Last modified on:2 years agoReading Time:4MinutesCase Study Questions for Class 9 Science Chapter 13 Why Do We Fall Ill 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,…

Download CBSE Books

Exam Special Series:

• Sample Question Paper for CBSE Class 10 Science (for 2024)
• Sample Question Paper for CBSE Class 10 Maths (for 2024)
• CBSE Most Repeated Questions for Class 10 Science Board Exams
• CBSE Important Diagram Based Questions Class 10 Physics Board Exams
• CBSE Important Numericals Class 10 Physics Board Exams
• CBSE Practical Based Questions for Class 10 Science Board Exams
• CBSE Important “Differentiate Between” Based Questions Class 10 Social Science
• Sample Question Papers for CBSE Class 12 Physics (for 2024)
• Sample Question Papers for CBSE Class 12 Chemistry (for 2024)
• Sample Question Papers for CBSE Class 12 Maths (for 2024)
• Sample Question Papers for CBSE Class 12 Biology (for 2024)
• CBSE Important Diagrams & Graphs Asked in Board Exams Class 12 Physics
• Master Organic Conversions CBSE Class 12 Chemistry Board Exams
• CBSE Important Numericals Class 12 Physics Board Exams
• CBSE Important Definitions Class 12 Physics Board Exams
• CBSE Important Laws & Principles Class 12 Physics Board Exams
• 10 Years CBSE Class 12 Chemistry Previous Year-Wise Solved Papers (2023-2024)
• 10 Years CBSE Class 12 Physics Previous Year-Wise Solved Papers (2023-2024)
• 10 Years CBSE Class 12 Maths Previous Year-Wise Solved Papers (2023-2024)
• 10 Years CBSE Class 12 Biology Previous Year-Wise Solved Papers (2023-2024)
• ICSE Important Numericals Class 10 Physics BOARD Exams (215 Numericals)
• ICSE Important Figure Based Questions Class 10 Physics BOARD Exams (230 Questions)
• ICSE Mole Concept and Stoichiometry Numericals Class 10 Chemistry (65 Numericals)
• ICSE Reasoning Based Questions Class 10 Chemistry BOARD Exams (150 Qs)
• ICSE Important Functions and Locations Based Questions Class 10 Biology
• ICSE Reasoning Based Questions Class 10 Biology BOARD Exams (100 Qs)

✨ Join our Online NEET Test Series for 499/- Only for 1 Year

1 thought on “ Case Study and Passage Based Questions for Class 9 Science Chapter 2 Is Matter Around Us Pure? ”

• Pingback: Is Matter Around Us Pure Class 9 Case Study Questions Science Chapter 2 - XAM CONTENT

Leave a Reply Cancel reply

Editable Study Materials for Your Institute - CBSE, ICSE, State Boards (Maharashtra & Karnataka), JEE, NEET, FOUNDATION, OLYMPIADS, PPTs

Discover more from Gurukul of Excellence

Subscribe now to keep reading and get access to the full archive.

Type your email…

Continue reading

Class 9 Science Case Study Questions PDF Download

• Post author: studyrate
• Post published:
• Post category: class 9th
• Post comments: 0 Comments

Class 9 Science Case Study Questions play a crucial role in the field of science education as they provide real-life scenarios for students to analyze, apply their knowledge, and develop problem-solving skills. This article aims to present a comprehensive collection of case study questions for Class 9 Science , covering various topics and concepts.

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

CBSE Class 9 Science Exam will have a set of questions based on case studies in the form of MCQs. The CBSE Class 9 Science Question Bank on Case Studies, provided in this article, can be very helpful to understand the new format of questions. Share this link with your friends.

If you want to want to prepare all the tough, tricky & difficult questions for your upcoming exams, this is where you should hang out.  CBSE Case Study Questions for Class 9  will provide you with detailed, latest, comprehensive & confidence-inspiring solutions to the maximum number of Case Study Questions covering all the topics from your  NCERT Text Books !

Table of Contents

CBSE Class 9th SCIENCE Chapterwise Case Study Question & Solution

Case study questions provide students with real-life scenarios that require critical thinking and application of scientific concepts. They help students understand the practical application of scientific principles and develop problem-solving skills in various scientific disciplines.

Chapterwise Case Study Questions for Class 9 Science

Inboard exams, students will find the questions based on assertion and reasoning. Also, there will be a few questions based on case studies. In that, a paragraph will be given, and then the MCQ questions based on it will be asked. For Science subjects, there would be 5 case-based sub-part questions, wherein a student has to attempt 4 sub-part questions.

• Case Study Questions for Chapter 1 Matter in Our Surroundings
• Case Study Questions for Chapter 2 Is Matter Around Us Pure?
• Case Study Questions for Chapter 3 Atoms and Molecules
• Case Study Questions for Chapter 4 Structure of Atom
• Case Study Questions for Chapter 5 The Fundamental Unit of Life
• Case Study Questions for Chapter 6 Tissues
• Case Study Questions for Chapter 7 Diversity in Living Organisms
• Case Study Questions for Chapter 8 Motion
• Case Study Questions for Chapter 9 Force and Laws of Motion
• Case Study Questions for Chapter 10 Gravitation
• Case Study Questions for Chapter 11 Work and Energy
• Case Study Questions for Chapter 12 Sound
• Case Study Questions for Chapter 13 Why do we Fall ill
• Case Study Questions for Chapter 14 Natural Resources
• Case Study Questions for Chapter 15 Improvement in Food Resources

The above  Case studies for Class 9 Science  will help you to boost your scores as Case Study questions have been coming in your examinations. These CBSE Class 9 Science Case Studies have been developed by experienced teachers of schools.studyrate.in for the benefit of Class 10 students.

Class 9 Maths Case Study Questions

Benefits of Case Studies in Science Education

Case studies offer several advantages over traditional teaching methods. Here are some key benefits:

• Real-World Application : Case studies present authentic scenarios, enabling students to understand how scientific concepts are applied in real-life situations.
• Critical Thinking : Analyzing case studies requires students to think critically, make connections, and apply scientific knowledge to solve problems.
• Interdisciplinary Approach : Case studies often involve multiple scientific disciplines, fostering an interdisciplinary understanding of complex issues.
• Engagement and Active Learning : Case studies actively engage students in the learning process, promoting active participation, discussion, and collaboration.
• Skill Development : Case studies develop essential skills such as analytical thinking, problem-solving, and effective communication of scientific concepts.

Importance of Practicing Case Study Questions

Practicing case study questions is crucial for Class 9 Science students to enhance their understanding and application of scientific concepts. Here’s why it is important:

• Application of Knowledge : Case studies allow students to apply their theoretical knowledge to practical situations, bridging the gap between theory and real-world scenarios.
• Developing Analytical Skills : Analyzing case studies improves students’ ability to identify relevant information, make connections, and draw logical conclusions.
• Problem-Solving Skills : Case studies present complex problems that require students to think critically and develop effective problem-solving strategies.
• Enhanced Exam Performance : Practicing case study questions familiarizes students with the format and types of questions they may encounter in exams, leading to improved performance.

Subjects Covered in the Case Study Questions for Class 9 Science

The case study questions for Class 9 Science cover the following subjects:

• Motion and Forces
• Light and Reflection
• Electricity
• Matter and Its Properties
• Atoms and Molecules
• Structure of the Atom
• Chemical Reactions
• Cell: The Fundamental Unit of Life
• Diversity in Living Organisms
• Natural Resources

Tips for Approaching Case Study Questions

To tackle case study questions effectively, consider the following tips:

• Read Carefully : Pay close attention to the details provided in the case study, as they hold crucial information for solving the problem.
• Analyze Methodically : Break down the problem into smaller components and analyze each part systematically.
• Apply Relevant Concepts : Identify the scientific principles relevant to the case study and apply them appropriately.
• Consider Multiple Perspectives : Explore different angles and viewpoints while proposing solutions, taking into account various scientific factors.
• Provide Justifications : Support your answers with scientific explanations and logical reasoning to strengthen your responses.

The Class 9 Science Case Study Questions provided in this article serve as a valuable resource for students seeking to enhance their scientific knowledge and problem-solving skills. By practicing these case studies, students can develop a deeper understanding of scientific concepts and their practical applications. Embrace this opportunity to engage with real-world scenarios and strengthen your scientific acumen.

Q1: Are the Class 9 Science Case Study Questions aligned with the official curriculum?

Yes, the Class 9 Science Case Study Questions presented in this article are aligned with the official curriculum. They cover relevant topics and concepts that students need to study for their exams.

Q2: Can practicing case study questions alone guarantee success in Class 9 Science exams?

Practicing case study questions is an important part of exam preparation, but it should be complemented with a thorough understanding of the subject matter. It is advisable to study the concepts in detail, refer to textbooks, and engage in other learning activities to achieve success in exams.

Q3: Where I Can get Class 9 Science Case Study Questions ?

You can practice Class 9 Science Case Study Questions on schools.studyrate.in for free.

You Might Also Like

Class 9 science case study questions chapter 3 atoms and molecules, mcq questions of class 9 social science economics chapter 4 food security in india with answers, class 9 geography case study questions chapter 5 natural vegetation and wildlife, leave a reply cancel reply.

Save my name, email, and website in this browser for the next time I comment.

NCERT Solutions for Class 9 Science Chapter 2 Is Matter Around Us Pure

NCERT Solutions for Class 9 Science (chemistry) Chapter 2 Is Matter Around Us Pure 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 2 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 2 Textbook Questions and Answers

Intext Questions Page No. 15

Questions 1: what do mean by a pure substance?

Answer:  A pure substance is the one that consists of a single type of particles, i.e., all constituent particles of the substance have the same chemical nature. Pure substances can be Classified as elements or compounds.

Question 2: List the points of differences between homogeneous and heterogeneous mixtures. 

Page No. 18

Question 1: Differentiate between homogeneous and heterogeneous mixtures with examples. 

Answer:  A homogeneous mixture is a mixture having a uniform composition throughout the mixture. For example, mixtures of salt in water, sugar in water, copper sulphate in water, iodine in alcohol, alloy, and air have uniform compositions throughout the mixtures.  

On the other hand, a heterogeneous mixture is a mixture having a non-uniform composition throughout the mixture. For example, composition of mixtures of sodium chloride and iron fillings, salt and sulphur, oil and water, chalk powder in water, wheat flour in water, milk and water are not uniform throughout the mixtures.  

Question 2: How are sol, solution and suspension different from each other? 

Answer:  Sol is a heterogeneous mixture. In this mixture, the solute particles are so small that they cannot be seen with the naked eye. Also, they seem to be spread uniformly throughout the mixture. The Tyndall effect is observed in this mixture. For example: milk of magnesia, mud 

Solution is a homogeneous mixture. In this mixture, the solute particles dissolve and spread uniformly throughout the mixture. The Tyndall effect is not observed in this mixture. 

For example: salt in water, sugar in water, iodine in alcohol, alloy  

Suspensions are heterogeneous mixtures. In this mixture, the solute particles are visible to the naked eye, and remain suspended throughout the bulk of the medium. The Tyndall effect is observed in this mixture. 

For example: chalk powder and water, wheat flour and water 

Question 3: To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature. 

PAGE NO. 24 (I)

Question 1: How will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than 25°C), which are miscible with each other? 

Answer:   A mixture of two miscible liquids having a difference in their boiling points more than 25°C can be separated by the method of distillation. Thus, kerosene and petrol can be separated by distillation.

In this method, the mixture of kerosene and petrol is taken in a distillation flask with a thermometer fitted in it. We also need a beaker, a water condenser, and a Bunsen burner. The apparatus is arranged as shown in the above figure. Then, the mixture is heated slowly. The thermometer should be watched simultaneously. Kerosene will vaporize and condense in the water condenser. The condensed kerosene is collected from the condenser outlet, whereas petrol is left behind in the distillation flask.

Question 2: Name the technique to separate  (i) butter from curd (ii) salt from sea-water (iii) camphor from salt

Answer: (i) Butter can be separated from curd by centrifugation.

(ii) Salt can be separated from sea-water by evaporation.

(iii) Camphor can be separated from salt by sublimation.

Question 3: What type of mixtures is separated by the technique of crystallization? 

Answer:   By the technique of crystallization, pure solids are separated from impurities. For example, salt obtained from sea is separated from impurities; crystals of alum (Phitkari) are separated from impure samples.

PAGE NO 24(II)

Question 1: Classify the following as chemical or physical changes:

• Cutting of trees
• Melting of butter in a pan
• Rusting of almirah
• Boiling of water to form steam
• Passing of electric current through water and water breaking into hydrogen and oxygen gases.
• Dissolving common salt in water
• Making a fruit salad with raw fruits, and
• Burning of paper and wood

 Answer:  Cutting of trees → Physical change

Melting of butter in a pan → Physical change

Rusting of almirah → Chemical change

Boiling of water to form steam → Physical change

Passing of electric current through water, and water breaking down into hydrogen and oxygen gas → Chemical change

Dissolving common salt in water → Physical change

Making a fruit salad with raw fruits → Physical change

Burning of paper and wood → Chemical change

Question 2: Try segregating the things around you as pure substances or mixtures. 

Answer: Listed below are the classifications based on pure substances and mixtures:

Question 1: Which separation techniques will apply for the separation of the following?  (a) Sodium chloride from its solution in water. (b) Ammonium chloride from a mixture containing sodium chloride and ammonium chloride. (c) Small pieces of metal in the engine oil of a car. (d) Different pigments from an extract of flower petals. (e) Butter from curd. (f) Oil from water. (g) Tea leaves from tea. (h) Iron pins from sand. (i) Wheat grains from husk. (j) Fine mud particles suspended in water.

Answer:  (a) Sodium chloride from its solution in water → Evaporation

(b) Ammonium chloride from a mixture containing sodium chloride and ammonium chloride → Sublimation

(c) Small pieces of metal in the engine oil of a car → Centrifugation or filtration or decantation

(d) Different pigments from an extract of flower petals → Chromatography

(e) Butter from curd → Centrifugation

(f) Oil from water → Using separating funnel

(g) Tea leaves from tea → Filtration

(h) Iron pins from sand → Magnetic separation

(i) Wheat grains from husk → Winnowing

(j) Fine mud particles suspended in water → Centrifugation

Question 2: Write the steps you would use for making tea. Use the words – solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

Answer: 1. Take a cup of water in a container as solvent and heat it. 2. Add sugar in it which is solute. Heat it till all sugar dissolves. 3. You get a solution of water and sugar. 4. Sugar is soluble in water completely. 5. Add half a tea-spoon of tea-leaves, it is insoluble in water. 6. Boil the content, add milk which is also soluble in water, boil again. 7. Filter the tea with the help of strainer, the tea collected in cup is filtrate and the tea leaves collected on the strainer is residue.

Question 3: Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).

(a) What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?

(b) Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.

(c) Find the solubility of each salt at 293 K. Which salt has the highest solubility at this temperature?

(d) What is the effect of change of temperature on the solubility of a salt?

Answer: (a) Mass of potassium nitrate required to produce a saturated solution in 100 g of water at 313 K = 62g

∴ Mass of potassium nitrate required to produce a saturated solution in 50 g of water = (62 × 50)/100 = 31 Hence 31 g of potassium nitrate is required.

(b) Some amount of dissolved Potassium Chloride will reappear as undissolved solid as solubility of solute decreases with the decrease of temperature.

(c) Solubility of each salt at 393 K are as follows:

• Potassium nitrate – 32 g
• Sodium chloride – 36 g
• Potassium chloride – 35 g
• Ammonium chloride – 37 g
• Ammonium chloride has the highest solubility at 293 K.

(d) Solubility of salt increases with the increase in temperature.

Question 4: Explain the following giving examples. (a) Saturated solution, (b) Pure substance, (c) Colloid, (d) Suspension.

Answer: (a) Saturated Solution: A solution in which no more of the solid (solute) can be dissolved at a given temperature is called a saturated solution. Suppose 50 gm of a solute is the maximum amount that can be dissolved in 100 gm water at 298 K. Then 150 gm of solution so obtained is the saturated solution at 298 K.

A saturated solution is a solution in which the maximum amount of solute has been dissolved at a given temperature. The solution cannot dissolve beyond that amount of solute at that temperature. Any more solute added will settle down at the bottom of the container as a precipitate. Suppose 500 g of a solvent can dissolve a maximum of 150 g of a particular solute at 40°C. Then, the solution obtained by dissolving 150 g of that solute in 500 g of that solvent at 300 K is said to be a saturated solution at 300 K.

Pure Substance: A pure substance consists of a single of matter or particles and cannot be separated into other kind of matter by any physical process. Pure substances always have the same colour, taste and texture at a given temperature and pressure. For example, pure water is always colourless, odorless and tasteless and boils at 373 K at normal atmospheric pressure.

Colloid: Colloid A colloid is a heterogeneous mixture. The size of the solutes in this mixture is so small that they cannot be seen individually with naked eyes, and seems to be distributed uniformly throughout the mixture. The solute particles do not settle down when the mixture is left undisturbed. This means that colloids are quite stable. Colloids cannot be separated by the process of filtration. They can be separated by centrifugation. Colloids show the Tyndall effect. For example, milk, butter, foam,fog, smoke, clouds.

Suspension: Suspension Suspensions are heterogeneous mixtures. The solute particles in this mixture remain suspended throughout the bulk of the medium. The particles can be seen with naked eyes. Suspension shows the Tyndall effect. The solute particles settle down when the mixture is left undisturbed. This means that suspensions are unstable. Suspensions can be separated by the method of filtration. For example, mixtures of chalk powder and water, wheat flour and water.

Question 5. Classify each of the following as a homogeneous or heterogeneous mixture: soda water, wood, air. soil, vinegar, filtered tea.

Answer:   Homogeneous:  Soda water, vinegar, filtered tea. Heterogeneous:  Wood, air, soil.

Question 6. How would, you confirm that a colourless liquid given to you is pure water?

Answer:  We can confirm if a colourless liquid is pure by setting it to boil. If it boils at 100°C it is said to be pure. But if there is a decrease or increase in the boiling point, we infer that water has added impurities hence not pure.

Question 7. Which of the following materials fall in the category of a “pure substance”? (a) Ice (b) Milk (c) Iron (d) Hydrochloric acid (e) Calcium oxide (f) Mercury (g) Back (h) Wood (i) Air.

Answer:  Following substances from the above-mentioned list are pure substances:

• Hydrochloric acid
• Calcium oxide

Question 8. Identify the solutions among the following mixtures. (a) Soil (b) Sea water (c) Air (d) Coal (e) Soda water.

Answer:  The following are the solutions from the above-mentioned list of mixture:

Question 9. Which of the following will show “Tyndall effect”? (a) Salt solution (b) Milk (c) Copper sulphate solution (d) Starch solution.

Answer:  Milk and starch solution will show the “Tyndall effect”.

Question 10. Classify the following into elements, compounds and mixtures. (a) Sodium (b) Soil (c) Sugar solution (d) Silver (e) Calcium carbonate (f) Tin (g) Silicon (h) Coal (i) Air (j) Soap (k) Methane (l) Carbon dioxide (m) Blood

Question 11. Which of the following are chemical changes? (a) Growth of a plant (b) Rusting of iron (c) Mixing of iron filings and sand (d) Cooking of food (e) Digestion of food (f) Freezing of water (g) Burning of a candle.

Answer:  Chemical changes are: (a) Growth of a plant (b) Rusting of iron (d) Cooking of food (e) Digestion of food (g) Burning of candle

Class 9 Science NCERT Solutions Chapter 2 Is Matter Around Us Pure

CBSE Class 9 Science NCERT Solutions Chapter 2 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 2 PDF

Below we have listed the topics discussed in NCERT Solutions for Class 9 Science Chapter 2. The list gives you a quick look at the different topics and subtopics of this chapter.

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

Talk to our experts

1800-120-456-456

Important Questions for CBSE Class 9 Science Chapter 2 - Is Matter Around Us Pure

• Class 9 Important Question
• Chapter 2: Is Matter Around Us Pure

CBSE Class 9 Science Chapter-2 Important Questions - Free PDF Download

This chapter contains important questions for CBSE Class 9 Science Chapter 2 - Is Matter Around Us Pure in the form of free to download review notes. These questions will undoubtedly aid students in improving their understanding of Chapter 2 of Class 9 Science. Both homogeneous and heterogeneous states of mixtures are covered in Class 9 Science Chapter 2. In this chapter, students will also learn about matter and consider whether the surrounding stuff is pure.

Vedantu is a platform that provides free CBSE Solutions (NCERT) and other study materials for students. You can download Class 9 Science and Class 9 Maths NCERT Solutions to help you to revise the complete syllabus and score more marks in your examinations.

Download CBSE Class 9 Science Important Questions 2024-25 PDF

Also, check CBSE Class 9 Science Important Questions for other chapters:

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

Very Short Answer Questions (1 Mark)

1. Try segregating the things around you as pure substances or mixtures.

Ans: Try mixing soil and water then separate them. Where soil is a mixture as it is the mix of more than one substance. And water is a pure substance because it’s made up of one kind of substance.

2. Classify each of the following as a homogeneous or heterogeneous mixture. soda water, wood, air, soil, vinegar, filtered tea.

Ans: Classification of the given into homogeneous or heterogeneous is enlisted below.

3. How would you confirm that a colorless liquid given to you is pure water?

Ans: Under the  atmospheric pressure one, the boiling point of water is \[{{100}^{{}^\text{o}}}C\]. and freezing point is \[{{0}^{{}^\text{o}}}C\]. When we boil the given colorless liquid, if it boils at \[{{100}^{{}^\text{o}}}C\]then it is pure water. If not boiling at \[{{100}^{{}^\text{o}}}C\] temperature, then there will be impurities mixed with it, hence not pure water.

4. Which of the following materials fall in the category of a “pure substance”?

d) Hydrochloric acid

e) Calcium oxide

Ans: Pure substances: ice, iron, hydrochloric acid, calcium oxide, mercury.

5. Identify the solutions among the following mixtures.

b) Sea water

e) Soda water.

Ans: Solutions: seawater, air, soda water.

6. Which of the following will show the “Tyndall effect”?

a) Salt solution

c) Copper sulfate solution

d) Starch solution.

Ans: (b)Milk and (d)starch solution 

7. Classify the following into elements, compounds, and mixtures.

c) Sugar solution

e) Calcium carbonate

l) Carbon dioxide

m) Blood 

Ans: Classification of the given into elements, compounds, and mixtures are enlisted below.

8. Which of the following are chemical changes?

(a) Growth of a plant

(b) Rusting of iron

(c) Mixing of iron filings and sand

(d) Cooking of food

(e) Digestion of food

(f) Freezing of water

(g) Burning of a candle.

Ans: Chemical changes: rusting of iron, cooking of food, digestion of food, burning of a candle.

9. Which of the following solutions scatter light?

(a) colloidal solution

(b) suspension

(d) none 

Ans: (c) both

10. Which of the following methods would you use to separate cream from milk?

(a) fractional distillation

(b) distillation

(c) centrifugation

(d) filtration

Ans: (c) Centrifugation

11. Cooking of food and digestion of food:

(a) are both physical processes, (b) are both chemical processes, (c) cooking is physical whereas digestion is chemical.

(d) Cooking is chemical whereas digestion physical 

Ans: (b) Are both chemical processes

12. Mercury and Bromine are both

(a) liquid at room temperature

(b) solid at room temperature

(c) gases at room temperature

(d) both (a) and (b)

Ans: (a) liquid at room temperature

13. Blood and seawater are:

(a) both mixtures

(b) both are compound

(c) blood is a mixture whereas seawater is a compound, (d) blood is a compound and seawater is a mixture , ans: (a) both mixtures.

14. Sol and Gel are examples of examples of

(a) Solid-solid colloids

(b) Sol is a solid-liquid colloid and Gel is a liquid-solid colloid

(c) Sol is a solid-solid colloid and Gel is a solid-liquid colloid

(d) Sol is a liquid-solid colloid and Gel is a solid-liquid colloid

Ans: (b) Sol is a solid-liquid colloid and Gel is a liquid-solid colloid

15. In a water-sugar solution:

(a) water is solute and sugar is solvent

(b) water is solvent and sugar is solute

(c) water is solute and water is also solute

(d) none of these

16. boron and carbon:.

(a) are metalloids

(b) boron is metalloid and carbon is non-metal

(c) boron is metallic and carbon is a metal

(d) boron is non-metal and carbon are a metalloid

Ans: (a) are metalloids

Short Answer Questions (2 Marks)

1. What is meant by a substance?

Ans: Substance will have similar chemical properties and can be defined as that kind of matter where constituent particles cannot be separated from each other by any physical process. 

2. How will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than \[{{25}^{{}^\text{o}}}C\] ), which are miscible with each other?

Ans: We can use the distillation technique to separate a mixture containing kerosene and petrol since the difference in their boiling points is more than \[{{25}^{{}^\text{o}}}C\].

3. Name the technique to separate

(i) Butter from curd

Ans: Centrifugation method.

(ii) Salt from sea-water

Ans: Evaporation method.

(iii) Camphor from salt

Ans: Sublimation method.

4. What type of mixtures are separated by the technique of crystallization?

Ans: From liquid solutions of impure samples, pure solid crystals can be separated. This method is known as crystallization. 

Example: Pure sugar from impure sugar, salt from seawater.

5. What is a mixture? What are its various types?

Ans: A mixture is constituted by more than one element or compound or both mixed in any proportion. They are of two types:

(a) Homogenous mixture

(b) Heterogeneous mixture

6. Define solute, solvent, and solution?

Ans: Solute: It is the substance of the solution which is being added to the solvent.

Solvent: It dissolves the solute. The component of the solution to which the solute is added.

Solution: It is homogeneous, constituted by solute and solvent.

7. What is a solution? What are the properties of the solution?

Ans: A solution is a homogenous mixture of two or more substances. The various properties of the solution are: -

The particles of a solution cannot be seen by naked eyes because they are smaller than $1$ nm.

When the beam of light passes through a solution, it does not scatter.

Filtration cannot be used to separate the components of a solution from each other. 

8. Differentiate between elements and compounds.

Ans: The difference between elements and compounds is enlisted below.

9. What is the Tyndall effect? Which kinds of solutions show it?

Ans: Tyndall effect is a process in which the scattering of beams of light takes place in particles of a colloid when that is directed towards them. Heterogeneous mixtures like Suspension solution and colloidal solution show the Tyndall effect.

10. Differentiate between homogeneous and heterogeneous mixture?

Ans: The difference between homogeneous and heterogeneous mixtures are listed below.

11. What is centrifugation? Where it is used?

Ans: Centrifugation is a technique used for the separation of suspended particles of a substance from liquid and is based upon the principle that denser particles stay at the bottom and lighter particles stay at the top when rotated at a high speed in a centrifuge application . It is used in separate butter from milk, also in washing machines for squeezing out water from clothes.

12. What is a suspension? What are the properties of suspension?

Ans: A suspension is a heterogeneous mixture in which the solute particles do 

not dissolve in the solvent but remain suspended throughout the bulk of the medium. The suspension particle size is large enough to be visible from naked eyes.

Properties of suspension:

The particles are large so can be seen by naked eyes.

They scatter a beam of light passing through it.

When particles are left undisturbed, they settle down.

Short Answer Questions (3 Marks)

1. How are sol, solution, and suspension different from each other?

Ans: The difference between sol, solution, and suspension are enlisted below.

2. To make a saturated solution, $36$ g of sodium chloride is dissolved in \[100\] g of water at \[293\] K. Find its concentration at this temperature.

Ans: In the problem, it is given that to make a saturated solution, $36$ g of sodium chloride is dissolved in \[100\] g of water at \[293\] K. 

Mass of sodium chloride (solute) is $36$ g 

Mass of water (solvent) is \[100\] g

Mass of solution is the sum of solute and solvent 

\[\Rightarrow 36+100=136\]

Therefore, concentration percentage \[=\dfrac{mass\text{ }of\text{ }solute}{mass\text{ }of\text{ }solution}\times 100\]

$=\dfrac{36}{136}\times 100$

3. Classify the following as chemical or physical changes:

cutting of trees

melting of butter in a pan

rusting of almirah

boiling of water to form steam

the passing of electric current through water and the water breaking    down into hydrogen and oxygen gases

dissolving common salt in water

Making a fruit salad with raw fruits burning of paper and wood.

Ans: When the chemical properties of a substance change then it’s called a chemical change.

Chemical change: rusting of almirah, passing of electric current, through water and the water breaking down into hydrogen and oxygen gases, burning of paper and wood.

Physical properties of a substance such as a shape, size, color, state change then it’s called a physical change.

Physical change: cutting of trees, melting of butter in a pan, boiling of water to form steam, dissolving common salt in water, making a fruit salad with raw fruits.

4. Which separation techniques will you apply for the separation of the following?

a) Sodium chloride from its solution in water.

Ans: Evaporation method

b) Ammonium chloride from a mixture containing sodium chloride and 

Ammonium chloride., ans: sublimation method, c) small pieces of metal in the engine oil of a car..

Ans: Filtration method

d) Different pigments from an extract of flower petals.

Ans: chromatography.

e) Butter from curd.

Ans: Centrifugation method

f) Oil from water.

Ans: by using separating funnel.

g) Tea leaves from tea.

Ans: Filtration by using a strainer

h) Iron pins from sand.

Ans: magnetic separation.

i) Wheat grains from husk.

Ans: Winnowing method

j) Fine mud particles suspended in water.

5. write the steps you would use for making tea. use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate, and residue..

Ans: First, take the required amount of water as a solvent in a pan, and after boiling it add a little amount of sugar which is solute to the solvent. The solute will dissolve completely in the solvent forming the true solution, then add tea leaves that are insoluble along with another soluble liquid milk. After boiling the solution use the method of filtration with a sieve so that the filtrate obtained is tea while the residue has tea leaves that can be thrown away.

6. Pragya tested the solubility of three different substances at different temperatures and collected the data as given below(results are given in the following table, as grams of substance dissolved in $100$ grams of water to form a saturated solution)

a) What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in \[50\] grams of water at $313$ K?

Ans: At temperature $313$ K the amount of potassium nitrate required was $62$ g in $100$ ml of water.

Therefore, in \[50\] g water we will need to dissolve $62\times \dfrac{50}{100}=31$ g potassium nitrate.

b) Pragya makes a saturated solution of potassium chloride in water at $353$ K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.

Ans: at $353$ k saturated solution preparation needs \[54\] g potassium nitrate and at room temperature (\[293\]k) saturation solution formation occurs with \[35\] g potassium nitrate hence \[5435=19\] g potassium nitrate will precipitate out as undissolved salt..

c) Find the solubility of each salt at \[293\] K. Which salt has the highest solubility at this temperature?

Ans: Solubilities are (in \[100\] mg of water) \[32,36,35,37\] respectively for the mentioned salts and the highest solubility is of ammonium chloride at this temperature.

d) What is the effect of change of temperature on the solubility of a salt?

Ans: Solubility of salts is directly proportional to the temperature i.e., if temperature increases then solubility will also increase, and if the temperature decreases then solubility will also decrease.

7. Explain the following examples.

(a) Saturated solution

Ans: It is a solution in which no more solute particles can be dissolved at a particular temperature.

(b) Pure substance

Ans: It is a substance that has a fixed composition and is made up of only one type of particle.

(c) Colloid

Ans: It is a substance that has a fixed composition and is made up of only one type of particle. It is a  kind of heterogeneous mixture/solution in which particle size is between $1$ nm and $1000$ nm that is intermediate between true solution and suspensions. Colloids have dispersion medium and dispersed phases.

(d) Suspension

Ans: It is a  kind of heterogeneous mixture, in which insoluble solid particles remain suspended in the medium and dispersion particles are visible to the bare eyes.

8. Write a method to separate different gases from the air.

Ans: Air is a homogeneous mixture of various gases.

Fractional distillation can be used to separate its various components.

(a) First, compress air by increasing the pressure and cool the air by decreasing the temperature.

(b) The obtained air is liquid air; now allow the liquid air to warm up slowly in a fractional distillation column.

(c) The various gases separate from each other according to their boiling points at various heights of the fractionating column.

9. What is a colloid? What are its various properties?

Ans: The heterogeneous mixture of substances are colloids, in which the particle size is too small and cannot be seen by naked eyes.

(1) It is a heterogeneous mixture but appears homogeneous.

(2) The size of particles is too small so cannot be seen by naked eyes.

(3) They make its path visible by scattering the beam of light passing through it.

(4) When the colloid is left undisturbed, the particles of it do not settle down.

10. A solution contains $60$ g of $NaCl$ in $400$ g of water. Calculate the concentration in terms of mass-by-mass percentage of the solution.

Ans: In the problem, it is given that, A solution contains $60$ g of $NaCl$ in 400g of water. 

Mass of solute ($NaCl$) is $60$ g

Mass of solvent (water) is $400$ g

Mass of solution $=$ Mass of solute $+$ Mass of solvent

$\Rightarrow 60+400=460$ g

Mass percentage of the solution is the percentage of the ratio of the mass of solute to the mass of solution.

\[\Rightarrow \dfrac{60}{460}\times 100=\dfrac{300}{23}~~\]

\[=13.4\%\]

11. Differentiate between metals and non-metal based upon the various properties that they show.

Ans : the difference between metals and non-metal based upon the various properties are enlisted below..

12. Differentiate between mixtures and compounds by giving appropriate examples?

Ans : differences between mixtures and compounds are enlisted below..

13. Write a method to separate a mixture of salt and ammonium chloride?

Ans: A mixture of salt and ammonium chloride can be separated by the process of sublimation. In this process, the solid substance is directly converted into a gaseous state.  Since ammonium chloride changes directly from a solid into a gaseous state on heating and salt does not have that property, this principle can be used to the mixture of two.

The mixture of $N{{H}_{4}}Cl$ (ammonium chloride) and salt is taken in a china dish inside an inverted funnel.

The mixture is then heated using a burner and because $N{{H}_{4}}Cl$ sublimates thus it changes into vapors directly.

Salt settles into the inverted funnel as it is a non-sublimely substance.

Separation of $N{{H}_{4}}Cl$ salt by sublimation

14. What is crystallization? Where is it used? Why is this better than the simple evaporation technique?

Ans: Crystallization is the process of the transformation of solution into pure solid in the form of crystals. It is used to purify solids. For example, salt from seawater is purified using crystallization. It is a better technique than simple evaporation because:

Some solids may decompose or get charred on heating to dryness during evaporation.

Some of the impurities will remain dissolved in the solution.

15. What is chromatography? What are its various applications and underline the basic principle involved?

Ans: A technique used for the separation of those components whose solubility is different in the same solvent is chromatography. The basic principle in chromatography is that different solutes have different solubility in the same solvent.

Its various applications are:

It is used to separate different colors in dye .

It is used to separate pigments from natural colors.

It is used to separate drugs from the blood.

16. A solution of \[{{H}_{2}}S{{O}_{4}}\] acid is labeled is \[95\%\]. What is the mass of this that must be diluted with water to get \[5\]L of a solution containing \[10\] g of \[{{H}_{2}}S{{O}_{4}}\] per litre?

Ans: In the problem, it is given that, A solution of \[{{H}_{2}}S{{O}_{4}}\] acid is labeled is \[95\%\].

\[1\] L of the diluted solution must contain \[10\] g of \[{{H}_{2}}S{{O}_{4}}\]. Therefore, \[5\] L of the diluted solution must contain \[50\] g of \[{{H}_{2}}S{{O}_{4}}\].

The concentration of the acid in the bottle is \[95\%\] as per the problem.

This means that,

\[95\] g of \[{{H}_{2}}S{{O}_{4}}\] is present in \[100\] g of the acid solution .

\[50\] g of \[{{H}_{2}}S{{O}_{4}}\] will be present in \[\dfrac{\left( 50\times 100 \right)}{95}=52.64\] g of the solution.

Chemistry plays an important role in everyone's life, we might not know much about it but it is present in our everyday life, that is what this chapter tries to show where it indicates the different types of matters that are present everywhere around us. In this chapter, students will learn how matter is composed of and how it differs from various substances. Regular practice of Chapter 2 Class 9 Important Questions can help students improve, become through the concepts and topics, and be efficient during preparation or revision. Students must learn to utilize the material given to them to get more marks. In this article, we will also look at Class 9 Science Chapter 2 extra questions .

Important Questions for CBSE Class 9 Science Chapter 2 - Is Matter Around Us Pure - Benefits of Class 9th Science Chapter 2 Important Questions

It is vital that students understand the importance of this subject and what it holds for students of Class 9. By utilising the important questions and with a rigorous practice regime, students will be able to score the most out of their exams. These exams can be a little difficult without the right guidance but by using Vedantu’s important questions on Chapter 2, students will be able to study in a more structured manner. Following is the list of benefits:

Students can use Vedantu to use their time wisely, it helps boost their confidence after consistent practice and students can plan their preparation accordingly. 

It provides students with a structure with which they can study for their upcoming examinations. 

This is a fundamental chapter for students and plays a crucial role in upcoming grades. 

Students don’t have to worry about the relevance of these questions as they are all cross-checked and updated according to the latest CBSE guidelines and rules. So, the information in this article is genuine and reliable.

Topics Covered under CBSE Class 9 Chapter 2 ‘Is Matter Around Us Pure’ 

Following are the topics that are covered in CBSE Class 9 Chapter 2 ‘Is Matter Around Us Pure’:

Matter and its Types

Metals, Non-metals, and Metalloids

Mixture and its Types

Solution and its Types

Factors Affecting the Solubility

Concentration of Solution

Key Takeaways of CBSE Class 9 Science Chapter 2 Is Matter Around Us Pure 

Students here will learn some of the basic elements of constituents of matters. This will help them in their future grades as it sets the groundwork. Constant practice of the essential questions should help students to tackle any difficult questions in their final examinations. Some of the topics that these chapter covers are as follows:

Chemistry 

This subject is known as the central science subject that connects all the science subjects. This subject is very detailed and helps students understand the chemical constituents in different materials. it is connected to a lot of the physical subjects together such as Chemistry with Applied Science and Life Sciences such as Engineering and Medicine. Chemistry is defined as the study of the interaction, composition, and properties of matter.

Homogeneous and Heterogeneous Mixture 

These are two very different mixtures as in a homogeneous mixture, it has a uniform composure of its constituents where heterogeneous is a nonuniform composure of its constituents.

Tyndall Effect 

The scattering of a beam of light by particles of a solution when light is passed through it is known as the Tyndall effect. The solution where the size of the particle is very small.

Matter is defined as anything that possesses mass, occupies space, and the presence that can be felt by the five senses. Matter exists in three forms, namely, a solid, liquid, and gas. Solids are substances that possess a definite structure and a definite shape like sugar, iron, etc. Liquids are substances that have a definite volume but lack a definite form and take the shape of the vessel in which they are put — for example, mercury, milk, water, etc. Gases are substances that can neither possess a definite shape or definite volume like hydrogen, oxygen, nitrogen, etc.

The Difference Between Mixture and Compound 

This chapter takes a detailed look into the difference between mixture and compounds. The mixture is basically the elements or compounds that are mixed together in a heterogeneous way. It has a variable composition and also shows us the properties of constituent elements and the various ways in which they can be mixed. The examples are air, blood, and water. In a compound when the elements react, they form new compounds. This new substance formed shows new properties and examples of this are sodium chloride.

Crystallisation 

This is a very important process where we can separate the pure solid in the form of its crystals from its solutions. This is an important process when forming crystals. Unlike many processes where the solids may decompose because of the heat during the process of decomposition. In the process of evaporations, some solids stay intact.

Substance 

In this situation, it is physically impossible to separate the constituent particles from one another on one's own. Chemical or electrochemical procedures can be used to separate them because their chemical properties are similar. A material possesses particular qualities or attributes. Physical properties and chemical properties are the two main categories into which properties of matter can be divided. Melting point, boiling point, colour, aroma, and other physical attributes can be observed or quantified without affecting the content or identification of the substance. Chemical characteristics, such as combustibility, basicity, or acidity, are the chemical transformations that result in a distinctive response.

Chromatography 

This is a process where substances used for the separation of different substances have different solubility in the same solvent. It is used to separate different colours in the dye. It is used to separate different pigments from natural colours and separate drugs from the blood. There are various ways in which they can be separated and we will learn that in this chapter.

Colloid 

These are heterogeneous mixtures of substances whose particles are too small for the naked eye and cannot be seen. It appears homogeneous but is actually a heterogeneous mixture. The particles are too small for the naked eye to see. They scatter a beam of light through it and make its path invisible. The particles of the colloid do not settle down when left undisturbed. 

Important Questions on CBSE Class 9 Science Chapter 2 - Is Matter Around Us Pure 

To get a better understanding of Class 9 Science Chapter 2 important questions , let's look at how the various essential questions are framed and how they can be beneficial to students. Using the following questions should help students in the long term. 

1. What is chromatography? What are its various applications and underline the basic principles involved?

2. What is crystallisation? Why is crystallisation used? 

3. Why is crystallisation a better technique than the evaporation process?

4. Write a method to separate salt from sodium chloride.

5. Differentiate between mixture and compound by giving appropriate examples.

6. Differentiate between metals and non-metals based on the various metal properties they show.

7. What is a colloid? 

8. What are the various properties of a colloid? 

9. Write a different method to separate gas from the air?

10. Explain and give the example of the following: 

a. Saturated solution 

b.Pure substance 

c. Colloid 

d.Suspension

Tips to Study Science Better

Following are some tips that will help the students to study science in a better way:

Follow the concepts and study them properly. 

Try out the experiments under the guidance of someone elderly, which will help you to understand the topic better.

Practise solving the questions and answers, this will increase your chance of getting better results.

Practise with reliable notes for this chapter, you can refer to Is Matter Around Us Pure Class 9 Notes CBSE Science Chapter 2 (Free PDF Download) of Vedantu, this is quite reliable.

Conclusion 

The Situation in the Matter Around Us Pure, students have found pure important questions to be incredibly helpful. As you can see from this article, this chapter is very important for students to begin their study of chemistry because it essentially lays the foundation for subsequent grades. This article can help students make the most of their time, build their confidence after constant practice, and manage their study sessions effectively. Students might aspire for higher grades by working more hard toward their goals. These significant questions ensure that students understand the chapter's numerous concepts, and with continued practice, they will develop the skills necessary to answer the challenging questions on exams.

Important Related Links for CBSE Class 9 

FAQs on Important Questions for CBSE Class 9 Science Chapter 2 - Is Matter Around Us Pure

1. What are the major differences between a mixture and a compound?

Mixture: Elements or compounds just mix together to form a mixture. It has a variable composition and shows the properties of constituent elements. These constituent particles can be separated by physical methods. For example, air, blood, etc.

Compound: When elements chemically react, they form new compounds. Compounds have a fixed composition. The new substance formed shows new properties. The constituent elements can only be separated by chemical methods. For example, Sodium Chloride, Calcium Sulphate, etc.

2. What is crystallisation? Why is it an important process?

Crystallisation is a process by which we can separate a pure solid in the form of crystals from its solutions. It is an important process which is used to purify solids. It is a better technique than many processes like simple evaporation as some solids may decompose on heating during evaporation. In evaporation, some impurities still remain dissolved in the solutions.

3. Where can I find Important Questions for CBSE Class 9 Science Chapter 2 - Is Matter Around Us Pure?

Students can find a set of important questions for Class 9 Chapter 2 Is Matter Around Us Pure on Vedantu, a reliable online learning site. Vedantu caters to solve important questions chosen from the exam perspective. These questions are answered by subject matter experts who have immense subject knowledge and expertise. The material is available in the free PDF format and can be downloaded at students’ convenience for learning and during exam preparation.

4. What is meant by a substance?

Substance can be defined as the kind of matter where constituent particles cannot be separated from one another with the help of any physical process. Since they are similar in chemical properties, they can also be separated by chemical or electrochemical methods. Examples are diamond, water, sulphur, etc.

5. What is the saturated solution according to Chapter 2 of Class 9 Science?

A saturated solution is a solution in which no more solute can be added without increasing the temperature of a solution. It is stable at room temperature.  Students study more about saturated solutions in their science books for Class 9. They will understand the concept of pure substances and matter too. All definitions related to different types of solutions and substances are given in detail on Vedantu.

6. What is a mixture and a compound according to Chapter 2 of Class 9 Science ?

A mixture and a compound are different from each other in many ways. A mixture is not a pure substance but a compound is a pure substance. A mixture has different constituents and the properties of the constituents do not change in a mixture but the properties of all constituents will change in a compound. In a mixture, two or more substances can be mixed together in any ratio whereas in a compound two or more substances are mixed together in a fixed ratio.

7. Write down the important properties of a colloidal solution?

Colloidal solutions are heterogeneous mixtures. The size of particles in a colloidal solution varies between 1nm and 100 nm. The particles are very small in size and cannot be seen easily. If the particles are left undisturbed, the solutions remain stable. Students of Class 9 can understand the concept of colloidal solution in Chapter 2. Students should read Chapter 2 of Class 9 carefully to understand the definitions of important terms given in the chapter.

8. Water acts as a compound and not a mixture. Give reasons.

Water acts as a compound because it is made of two components oxygen and hydrogen. The two constituents can be separated through the process of electrolysis. The two constituents are combined together in a fixed ratio of 1:2. The ratio of hydrogen and oxygen is fixed and does not change. It is not easy to separate the constituents of water easily. They can only be separated by a special process only called electrolysis.

9. What are the important features of important questions of Chapter 2 of Class 9 Science from Vedantu?

Important questions for Chapter 2 of Class 9 Science available on Vedantu include questions that can help students to score high marks in exams. These important questions are available at free of cost on Vedantu(vedantu.com) and mobile app. Important questions can also help students to understand the concepts and gain in-depth knowledge of all the concepts given in the chapter. Students can prepare for their exams by practising all-important questions given in Vedantu because they are prepared by expert and experienced teachers and professionals.

CBSE Class 9 Science Important Questions

Cbse study materials.

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

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.

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:

d.) None of these

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

Leave a Reply Cancel reply

We have a strong team of experienced teachers who are here to solve all your exam preparation doubts, west bengal board class 4 maths chapter 15 solutions কতটা রং করলাম দেখি, manipur board class 4 english chapter 20 my tree, kerala scert class 8 english rosa parks sat still question answer, kerala scert class 8 english the nightingale and the rose question answer.

NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12

Is Matter Around Us Pure Class 9 Extra Questions Science Chapter 2

October 2, 2019 by Sastry CBSE

Extra Questions for Class 9 Science Chapter 2 Is Matter Around Us Pure

Is Matter Around Us Pure Class 9 Extra Questions Very Short Answer Questions

Question 1. How can you change a saturated solution to an unsaturated solution without adding any more solvent to it? Answer: By heating the saturated solution, it becomes unsaturated.

Question 2. Sucrose (sugar) crystals obtained from sugarcane and beetroot are mixed together. Will it be a pure substance or a mixture? Give reasons for the same. [NCERT Exemplar] Answer: It is a pure substance because chemical composition of sugar crystals is same irrespective of its source.

Question 3. Based on which factor a solution is said to be diluted, concentrated or saturated? Answer: A solution is said to be diluted, concentrated or saturated on the basis of the amount of solute dissolved in the solution.

Question 4. Identify solute and solvent in ‘tincture of iodine’. Answer: Iodine is the solute and alcohol is the solvent.

Question 5. What is mass per cent of a solution? Answer: It is defined as the mass in grams of the solute present in one hundred grams of a solution.

Question 6. What are the two components of a colloidal solution? Answer: The two components of a colloidal solution are dispersed phase and dispersing medium.

Question 7. In what respect does a true solution differ from a colloidal solution? Answer: A true solution is homogeneous whereas a colloidal solution is heterogeneous.

Question 8. Two liquids ‘A’ and ‘B’ are miscible with each other at room temperature. Which separation technique will you apply to separate the mixture of ‘A’ and ‘B’ if the difference in their boiling points is 27°C? Answer: We can separate two miscible liquids by fractional distillation, if both the liquids have difference in their boiling points. So, the mixture of liquids ‘A’ and ‘B’ can be separated by fractional distillation.

Question 9. Define crystallisation. Answer: It is a process that separates a pure solid in the form of its crystals from a solution.

Question 10. Why is crystallisation technique considered better than simple evaporation to purify solids? Answer: Crystallisation is considered better than simple evaporation because

• some solids decompose or get charred on heating to dryness.
• some impurities may remain dissolved in the solution even after filtration. On evaporation, these contaminate the solid.

Question 11. Why is water called universal solvent? Answer: Water is known as universal solvent because it has the ability to dissolve wide variety of substances.

Question 12. Which of the following are physical changes? Melting of iron metal, rusting of iron, bending of iron rod, drawing a wire of iron metal. Answer: Melting of iron metal, bending of iron rod and drawing a wire of iron metal are physical changes because there is no change in the chemical composition of iron, only its form is changing.

Question 13. Name two elements which exist in liquid state at room temperature. Answer: Gallium and mercury exist in liquid state at room temperature.

Question 14. An unknown substance ‘A’ on thermal decomposition produces ‘B’ and ‘C’. What is ‘A’—an element, a compound or a mixture? Answer: Unknown substance ‘A’ should be a compound because elements and mixture do not decompose.

Question 15. Identify the elements from the following substances: sulphur, brine, hydrochloric acid, water, neon, paper, sugar. Answer: The elements are sulphur and neon.

Is Matter Around Us Pure Class 9 Extra Questions Short Answer Questions-I

Question 1. ‘Sea water can be classified as homogeneous as well as heterogeneous mixture.’ Comment. [NCERT Exemplar] Answer: Sea water is a mixture of salts and water which cannot be separated except by evaporation. Therefore, sea water is considered homogeneous. Sea water also contains mud, decayed plant, etc., other than salts and water, so it is heterogeneous also.

Question 2. Why is it not possible to distinguish particles of a solute from the solvent in solution? Answer: A true solution is homogeneous in nature. The solute and solvent particles are very small. They cannot be distinguished even under a microscope.

Question 3. Explain why particles of a colloidal solution do not settle down when left undisturbed, while in the case of a suspension they do. [NCERT Exemplar] Answer: Particle size in a suspension is larger than those in a colloidal solution. Also molecular interaction in a suspension is not strong enough to keep the particles suspended and hence they settle down.

Question 4. Identify colloids and true solutions from the following: Pond water, fog, aluminium paint, vinegar and glucose solution. Answer: True solutions are vinegar and glucose solution. Colloids are fog, aluminium paint.

Question 5. Give two examples each for

• Aerosol: Clouds, smoke
• Emulsion: Milk, face cream.

Question 6. Smoke and fog both are aerosols. In what way are they different? [NCERT Exemplar] Answer: Both fog and smoke have gas as the dispersion medium. The only difference is that the dispersed phase in fog is liquid and in smoke it is a solid.

Question 7. What do you understand by the term distillation? Give its one application. Answer: Distillation is a process of boiling a liquid and then condensing the vapour obtained into a liquid. This process is used to obtain wines from the sugarcane juice.

Question 8. While diluting a solution of salt in water, a student by mistake added acetone (boiling point 56°C). What technique can be employed to get back the acetone? Justify your choice. [NCERTExemplar] Answer: Distillation is used to get back acetone. We know that boiling point of water is 100°C and since acetone is more volatile it will separate out first.

Question 9. Define chromatography and give its one application. Answer: Chromatography is a technique used for the separation of a mixture of solutes brought about by distribution of dissolved material between two immiscible phases, one of which is mobile phase and the other part is stationary phase. It is useful in forensic science to detect and identify trace amounts of substances in the contents of bladder or stomach.

Question 10. Rain water stored in a tank contains sand grains, unfiltrable clay particles, calcium carbonate, salt, pieces of paper and some air bubbles. Select from amongst these one example each of a solvent, a solute, a colloid and a suspension. Answer: Solvent – water Solute – salt Colloid – air bubbles Suspension – clay particles.

Question 11. Classify the following as physical or chemical properties: (a) The composition of a sample of steel is 98% iron, 1.5% carbon and 0.5% other elements. (b) Zinc dissolves in hydrochloric acid with the evolution of hydrogen gas. (c) Metallic sodium is soft enough to be cut with a knife. (d) Most metal oxides form alkalis on interacting with water. [NCERT Exemplar] Answer: Physical properties—(a) and (c) Chemical properties—(b) and (d)

Question 12. Give two points of differences between an element and a compound. Answer:

Question 13. Which of the following are not compounds? (a) Chlorine gas (b) Potassium chloride (c) Iron (d) Iron sulphide (e) Aluminium (f) Iodine (g) Carbon (h) Carbon monoxide (i) Sulphur powder Answer: Chlorine gas, iron, aluminium, iodine, carbon, sulphur powder.

Question 14. Is water an element or a compound? Give reason in support of your statement Answer: Water is a compound because of the following reasons:

• It is composed of two different elements, hydrogen and oxygen which cannot be separated by physical methods. They can be separated only by electrolysis.
• The physical and chemical properties of hydrogen and oxygen are entirely different from the properties of water.

Is Matter Around Us Pure Class 9 Extra Questions Short Answer Questions-II

Question 1. Identify the dispersed phase and dispersing medium in the following colloids. (a) Fog (b) Cheese (c) Coloured gemstone Answer: (a) Fog—liquid, gas (b) Cheese—liquid, solid (c) Coloured gemstone—solid, solid

Question 2. Describe any three properties of colloid. Answer:

• It is a heterogenous mixture.
• Size of particles is too small to be seen by naked eye.
• They scatter light passing through them making its path visible.
• They do not settle down when left undisturbed.
• They cannot be separated by the process of filtration, (any three points)

• Pour the mixture of kerosene oil and water in separating funnel as shown in figure.
• Let it stand undisturbed for sometime so that separate layers of oil and water are formed.
• Open the stopcock of the separating funnel and pour out the lower layer of water carefully.
• Close the stopcock of the separating funnel as the oil reaches the stopcock.

Question 4. What would you observe when (a) a saturated solution of potassium chloride prepared at 60°C is allowed to cool at room temperature? (b) an aqueous sugar solution is heated to dryness? (c) a mixture of iron filings and sulphur powder is heated strongly? [NCERT Exemplar] Answer: (a) Solid potassium chloride will separate out. (b) Initially the water will evaporate and then sugar will get charred. (c) Iron sulphide will be formed.

Question 5. Suggest separation technique (s) one would need to employ to separate the following mixtures: (a) Mercury and water (b) Potassium chloride and ammonium chloride (c) Common salt, water and sand (d) Kerosene oil, water and salt. [NCERT Exemplar] Answer: (a) Separation by using separating funnel (b) Sublimation (c) Filtration to separate sand followed by evaporation/distillation (d) Separation by using separating funnel to separate kerosene oil followed by evaporation or distillation.

Question 6. Name the process associated with the following: (a) Dry ice is kept at room temperature and at one atmospheric pressure. (b) A potassium permanganate crystal is in a beaker and water is poured into the beaker with stirring. (c) An acetone bottle is left open and the bottle becomes empty. (d) Milk is churned to separate cream from it. (e) Settling of sand when a mixture of sand and water is left undisturbed for some time. (f) Fine beam of light entering through a small hole in a dark room, illuminates the particles in its paths. [NCERT Exemplar] Answer: (a) Sublimation (b) Dissolution/diffusion (c) Evaporation/diffusion (d) Centrifugation (e) Sedimentation (f) Scattering of light (Tyndall effect).

Question 7. On heating, calcium carbonate gets converted into calcium oxide and carbon dioxide. (a) Is this a physical or a chemical change? (b) Can you prepare one acidic and one basic solution by using the products formed in the above process? If so, write the chemical equation involved. [NCERT Exemplar] Answer: (a) Chemical change. (b) Acidic and basic solutions can be prepared by dissolving the products of the above process in water. CaO + H 2 O → Ca(OH) 2 (basic solution) CO 2 + H 2 O → H 2 CO 3 (acidic solution)

Question 8. Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured. (a) Name a lustrous non-metal. (b) Name a non-metal which exists as a liquid at room temperature. (c) The allotropic form of a non-metal is a good conductor of electricity. Name the allotrope. (d) Name a non-metal which is known to form the largest number of compounds. (e) Name a non-metal other than carbon which shows allotropy. (f) Name a non-metal which is required for combustion. [NCERT Exemplar] Answer: (a) Iodine (b) Bromine (c) Graphite (d) Carbon (e) Sulphur (f) Oxygen

Question 9. Classify the following into metals, non-metals and metalloids: (i) Germanium (ii) Boron (iii) Diamond (iv) Iodine (v) Copper (vi) Helium. Answer: Metal – Copper Non-metals – Diamond, iodine and helium Metalloids – Germanium, boron.

Question 10. Classify the following into elements, compounds and mixtures. (i) Pure sand (ii) Air (iii) Ammonia gas (iv) Ice (v) Glass (vi) CaO. Answer: Elements – Nil Compounds – Pure sand, Ice, CaO, Ammonia gas Mixture – Air, Glass.

Is Matter Around Us Pure Class 9 Extra Questions Long Answer Questions

Question 8. You are provided with a mixture containing sand, iron filings, ammonium chloride and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture. [NCERT Exemplar] Answer:

• Removing iron filings from the mixture by magnetic separation. Take the mixture in a petri dish and roll a bar magnet over it. Iron filings will get attach to the magnet and thus separate from the mixture.
• Removing ammonium chloride by sublimation Transfer the remaining mixture into China dish and heat it. On heating, ammonium chloride sublimes and solidifies on condensation. The mixture containing sand and sodium chloride left behind in the China dish.
• Removing sand by filtration Make a solution of sand and sodium chloride in water. Filter the solution. Sodium chloride will dissolve in water and sand is left as residue on the filter paper.
• Evaporate the filtrate to dryness to get sodium chloride or by crystallisation.

Question 9. Classify each of the following as a physical or a chemical change. Give reasons. (a) Drying of a shirt in the sun. (b) Rising of hot air over a radiator. (c) Burning of kerosene in a lantern. (d) Change in the colour of black tea on adding lemon juice to it. (e) Churning of milk cream to get butter. [NCERT Exemplar] Answer: (a) It is a physical change because water is converted from its liquid state to gaseous state because of the sun’s heat. (b) It is a physical change because water in the radiator is converted from a liquid state to gaseous state. (c) It is a chemical change because combustion of kerosene occurs and new products are formed. (d) It is a chemical change because there is a reaction between the citric acid in the lemon and the compounds of tea resulting in formation of new products. (e) It is a physical change because the cream suspended in the milk is separated by churning.

Question 11. Iron filings and sulphur were mixed together and divided into two parts ‘A’ and ‘S’. Part ‘A’ was heated strongly while Part ‘S’ was not heated. Dilute hydrochloric acid was added to both the parts and evolution of gas was seen in both the cases. How will you identify the gases evolved? [NCERT Exemplar] Answer: Part A \(\mathrm{Fe}(s)+\mathrm{S}(s) \quad \stackrel{\mathrm{Heat}}{\longrightarrow} \quad \mathrm{FeS}(s)\) FeS(s) + 2HCl(aq) → FeCl 2 (aq) + H 2 S(g)

Part B Fe(i) + S(s) → Mixture of iron filings and sulphur When dilute HCl is added to it Fe(s) + S(s) + 2HCl(aq) → FeCl 2 (aq) + H 2 (g) Sulphur remains unreacted. H 2 S gas formed has a foul smell and on passing through lead acetate solution, it turns the solution black. Hydrogen gas burns with a pop sound.

Numericals Question 1. 0.5 g of salt is dissolved in 25 g of water. Calculate the percentage amount of the salt in the solution. Solution: Mass of salt present = 0.5 g Mass of water present in solution = 25 g ∴ Percentage amount of the salt = \(\frac{0.5}{0.5+25} \times 100\) = 1.96%

Question 8. How much water should be mixed with 12 mL of alcohol so as to obtain 12% alcohol solution? Solution: Volume of solute =12 mL Let the volume of water = x mL Volume of solution = (12 + x) mL Concentration of solution = \(\frac{\text { Volume of solute }}{\text { Volume of solution }} \times 100\) \(12=\frac{12}{12+x} \times 100\) 12 + x = 100 x = 100 – 12 = 88mL So, 88 mL of water should be mixed.

Is Matter Around Us Pure Class 9 Extra Questions Hots (Higher Order Thinking Skills)

Question 1. (a) Under which category of mixtures will you classify alloys and why? (b) A solution is always a liquid. Comment. (c) Can a solution be heterogeneous? [NCERT Exemplar] Answer: (a) Alloys are homogeneous mixture of two or more elements because the constituent elements mix together and give a mixture which is uniform throughout. (b) No, solid solutions and gaseous solutions are also possible. Examples are brass, air. (c) No, a solution cannot be heterogeneous in nature.

Question 2. The teacher instructed three students A’, ‘B’ and ‘C’ respectively to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). ‘A’ dissolved 50 g of NaOH in 100 mL of water, ‘B’ dissolved 50 g of NaOH in 100 g of water while ‘C’ dissolved 50 g of NaOH in water to make 100 mL of solution. Which one of them has made the desired solution and why? [NCERT Exemplar] Answer: ‘C’ has made the desired solution because 50% (mass by volume) solution means 50g of solute dissolved in 100 mL of solution. Mass by volume per cent = \(\frac{\text { Mass of solute }}{\text { Volume of solution }} \times 100\) = \(\frac{50}{100} \times 100\) = 50% mass by volume.

Question 3. Explain why filter paper cannot be used to separate colloids. Answer: The size of colloidal particles is less than lnm, while the size of pores present in an ordinary filter paper is larger than lnm. Hence, a colloidal solution cannot be separated by filtration.

Question 4. Three students A, B and C prepared mixtures using chalk powder, common salt and milk respectively in water. Whose mixture: (i) would not leave residue on filter paper after filtration? (ii) would show Tyndall effect? (iii) would give transparent/clear solution? (iv) would settle down at the bottom when left undisturbed? (v) could be filtered by filter paper? Answer: (i)

• Mixture of common salt and water.
• Mixture of milk and water.

(ii) Mixtures of chalk powder with water and milk with water. (iii) Mixture of common salt and water. (iv) Mixture of chalk powder and water. (v) Mixture of chalk powder and water.

Question 5. Can we separate alcohol dissolved in water by using a separating funnel? If yes, then describe the procedure. If not, explain. [NCERT Exemplar] Answer: We cannot separate alcohol dissolved in water by using separating funnel because both the components are highly soluble in each other. They can be separated by fractional distillation.

Question 6. What is the reason for running cold water through condenser from lower side to upper side in distillation process? Answer: In distillation process condensation of vapours take place. To absorb more heat, cold water is passed from lower side so that it will stay for longer time and absorb more heat from the vapours to form liquid state of the substance.

Question 7. You are given two samples of water labelled as ‘A’ and ‘B’. Sample ‘A’ boils at 100°C and sample ‘B’ boils at 102°C. Which sample of water will not freeze at 0°C? Comment. [ NCERT Exemplar] Answer: Sample ‘B’ will not freeze at 0°C because it is not pure water. At 1 atm, the boiling point of pure water is 100°C and the freezing point of pure water is 0°C.

Extra Questions for Class 9 Science

Free resources.

NCERT Solutions

Quick Resources

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

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 2 Is Matter Around Us Pure.

Table of Contents

Case Study Questions on Is Matter Around Us Pure

Question 1:

A group of students took an old shoe box and covered it with a black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and made another hole on the other side to view the light. They placed a milk sample contained in a tumbler in the box as shown in the figure below. They were amazed to see that milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it.

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

Q 1. Explain why the milk sample was illuminated? Name the phenomenon involved.

Q2. Same results were not observed with a salt solution. Explain.

Q 3. Can you suggest two more solutions which would show the same effect as shown by the milk solution?

Q 4. Give one example of above phenomenon observed in our surroundings.

• Because milk is a colloidal solution and would show Tyndall effect.
• Salt solution is a true solution and would not scatter light.
• Soap solution and ink solution.
• Tyndall effect is observed when sunlight passes through the canopy of a dense forest.

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

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

We hope the given case study questions for Is Matter Around Us Pure Class 9 helps you in your learning.

Topics from which case study questions may be asked

• Separation Techniques
• Concentration of Solutions
• Physical and Chemical Change
• Experiments and Observations

This chapter deals with the basic understanding of mixtures, solutions, separation techniques, physical change and chemical change. case study questions based on above topics may be asked.

Frequently Asked Questions (FAQs) on Is Matter Around Us Pure 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 “Is Matter Around Us Pure” 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 “Is Matter Around Us Pure” 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 “Is Matter Around Us Pure”.

Q7: What is meant by a substance?

A7: A material that consists of a single type of particles is known as pure substance. All constituent particles of pure substance have the same chemical nature.

Q8: List the points of differences between homogeneous and heterogeneous mixtures

A8: A homogeneous mixture is a mixture having a uniform composition throughout the mixture. For example: Salt in water, sugar in water, copper sulphate in water. A heterogeneous mixture is a mixture having a non-uniform composition throughout the mixture. For example: Sodium chloride and iron fillings, salt and sulphur, oil and water.

Q9: How can we check the purity of a substance?

A9: The purity of a substance can be checked by its melting point and boiling point. A pure substance has a fixed melting point or boiling point at constant pressure.

Q10: Define element.

A10: An element is a basic form of matter that cannot be broken down into simpler substances by chemical reaction. An element consists of only one kind of atom.

Q11: Define compound.

A11: A compound is a substance made up of two or more elements chemically combined with one another. A compound always contains a definite proportion of the elements by mass.

Q12: Name the three states of matter.

A12: The three states of matter are solid, liquid and gas.

Q13: Name the metal which is liquid at room temperature.

A13: Mercury

Q14: How will you separate a mixture of mercury, kerosene and water?

A14: The mixture of mercury, kerosene and water is taken in a separating funnel. Separating funnel is used to separate two immiscible liquids. The principle is that immiscible liquids separate out in layers depending on their densities. Mercury being the heaviest from the bottom layer, water form the middle layer and kerosene form the top layer. On opening the tap, mercury will run out first, followed by water and kerosene at the end

Related Posts

• NCERT Exemplar
• Science Exemplar Class 9
• Is Matter Around Us Pure

NCERT Exemplar Class 9 Science Solutions for Chapter 2 - Is Matter around Us Pure

Ncert exemplar solutions class 9 science chapter 2 – free pdf download.

NCERT Exemplar Solutions for Class 9 Science Chapter 2 Is Matter around Us Pure will aid you in understanding the types of questions that can be asked in CBSE Class 9 annual examinations and competitive examinations. Is Matter around Us Pure NCERT Exemplar is very important for your future prospects, as this chapter is a very fundamental chapter that lays a base for your higher studies. The solutions contain detailed explanations for each and every concept covered in the chapter. Students who find difficulty in understanding the concepts can access the solutions which are available online to get their doubts cleared instantly.

This NCERT Exemplar Class 9 Science has answers to the questions given in the textbook. It has different kinds of questions, such as multiple-choice questions, short answer questions and long answer questions, which will help you to gain in-depth knowledge from the examination perspective. The solutions are prepared by the experts in an interactive manner which enables students to have a better understanding of the important concepts. By regular practice of NCERT Solutions , students will be able to analyse the type of questions that would appear in Class 9 annual exams.

NCERT Exemplar for Class 9 Science Chapter 2 – Is Matter Around Us Pure

carouselExampleControls112

Previous Next

Access Answers to NCERT Exemplar for Class 9 Science Chapter 2 – Is Matter Around Us Pure?

Multiple-choice questions.

1. Which of the following statements is true for pure substances?

(i) Pure substances contain only one kind of particles

(ii) Pure substances may be compounds or mixtures

(iii) Pure substances have the same composition throughout

(iv) Pure substances can be exemplified by all elements other than nickel

(a) (i) and (ii)

(b) (i) and (iii)

(c) (iii) and (iv)

(d) (ii) and (iii)

The answer is b) (i) and (iii)

2. Rusting of an article made up of iron is called

(a) corrosion, and it is a physical as well as chemical change

(b) dissolution, and it is a physical change

(c) corrosion, and it is a chemical change

d) dissolution, and it is a chemical change

The answer is c) corrosion, and it is a chemical change.

Explanation :

Rusting of iron is corrosion, and it’s a chemical change because rust is a chemical compound called hydrated iron oxide Fe2O3. nH2O, iron(III), which is different from elemental iron.

Physical changes are those changes in which substance identity is not changed, and it can get back to its original form. For example, water freezing to ice can be melted back to waste, whereas chemical changes are those in which the original substance identity is changed, and they cannot be restored to their original form.

On adding solid solutes to the solvent, some solute dissolves, and their concentration increases in the solution. This process is known as dissolution.

Crystallisation is a process in which solute particles in a solution collide with the solid solute particles to get separated out of the solution.

3. A mixture of sulphur and carbon disulphide is

(a) heterogeneous and shows the Tyndall effect

(b) homogeneous and shows the Tyndall effect

(c) heterogeneous and does not show the Tyndall effect

(d) homogeneous and does not show the Tyndall effect

The answer is a) heterogeneous and shows the Tyndall effect.

Explanation:

A mixture of sulphur and carbon disulphide is a heterogeneous colloid and shows the Tyndall effect because, in a colloidal solution, the particles are big enough to scatter light. The scattering of light by colloidal particles is known as the Tyndall effect. Colloids are actually heterogeneous in nature though they appear to be homogeneous.

4. Tincture of iodine has antiseptic properties. This solution is made by dissolving

(a) iodine in potassium iodide

(b) iodine in vaseline

(c) iodine in water

(d) iodine in alcohol

The answer is (d) iodine in alcohol

The tincture is prepared by using 2-7% elemental iodine and either potassium iodide or sodium dissolved in alcohol. Since alcohol is a good solvent and iodine does not dissolve in water answer should be alcohol.

5. Which of the following are homogeneous in nature?

a. (i) and (iii)

b. (ii) and (iv)

c. (i) and (iv)

d. (iii) and (iv)

The answer is (c) (i) and (iv)

Explanation

Air and ice are homogeneous mixtures because their elements are not visible and cannot be distinguished from one another.

6. Which of the following are physical changes?

(i) Melting of iron metal

(ii) Rusting of iron

(iii) Bending of an iron rod

(iv) Drawing a wire of iron metal

(a) (i), (ii) and (iii)

(b) (i), (ii) and (iv)

(c) (i), (iii) and (iv)

(d) (ii), (iii) and (iv)

The answer is (c) (i), (iii) and (iv)

Rusting of iron is a chemical process where iron reacts with water and oxygen to produce iron oxide, whereas other processes are physical changes.

7. Which of the following are chemical changes?

(i) Decaying of wood

(ii) Burning of wood

(iii) Sawing of wood

(iv) Hammering of a nail into a piece of wood

(b) (ii) and (iii)

(d) (i) and (iv)

The answer is (a) (i) and (ii)

Decaying of wood and burning of wood, because there will be a change of chemical composition and wood cannot be restored to its original form.

Sawing of wood and hammering of nails into a piece of wood are physical processes where the chemical composition of compounds is not changed.

8. Two substances, A and B, were made to react to form a third substance, A 2 B, according to the following reaction 2A + B → A 2 B. Which of the following statements concerning this reaction are incorrect?

(i) The product A 2 B shows the properties of substances A and B

(ii) The product will always have a fixed composition

(iii) The product so formed cannot be classified as a compound

(iv) The product so formed is an element

(a) (i), (ii) and (iii),

(b) (ii), (iii) and (iv)

A 2 B is a compound made up of two elements, A and B, in a fixed ratio. The properties of a compound (For example, A 2 B) are entirely different from those of its constituent elements (i,e.g A and B). The composition of a compound is fixed.

9. Two chemical species, X and Y, combine together to form a product P which contains both X and Y X + Y → P. X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following concerning the species X, Y and P are correct?

(i) P is a compound

(ii) X and Y are compounds

(iii) X and Y are elements

(iv) P has a fixed composition

(c) (ii), (iii) and (iv)

(d) (i), (iii) and (iv)

The answer is (d) (i), (iii) and (iv)

Here, X and Y cannot be further broken down into simpler substances. Hence, X and Y are elements, and P can be broken down into its elements, P is a compound with a fixed composition.

Short Answer Questions

10. Suggest separation technique(s) one would need to employ to separate the following mixtures.

(a) Mercury and water

(b) Potassium chloride and ammonium chloride

(c) Common salt, water and sand

(d) Kerosene oil, water and salt

Answers are a) decantation, b) Sublimation, c) Filtration and evaporation, d) decantation and evaporation

Explanation a) Decantation method is used to separate the mixture of Mercury and water. Here Mercury is heavier than water hence it forms a separate layer which can be easily separated in a separating funnel.

b) Potassium chloride and ammonium chloride are separated by sublimation method because ammonium chloride is a sublimate, sublimes leaving behind the potassium chloride.

(d) Kerosene is separated from salt solution in water by decantation using a separating funnel. Kerosene being heavier, forms a separate layer. Salt from water is further removed by evaporation.

11. Which of the tubes in Fig. 2.1

(a) and (b) will be more effective as a condenser in the distillation apparatus?

The answer is: tube (a)

Beads in tube A provide an increased surface area for cooling of the vapours that come in contact with them. Hence, it is a good condenser.

12. Salt can be recovered from its solution by evaporation. Suggest some other technique for the same.

Answer is crystallization

Salt can be recovered from its solution by crystallization. Crystallization is a more efficient process as it removes soluble impurities, which cannot be done by evaporation.

13. The ‘seawater’ can be classified as a homogeneous as well as heterogeneous mixture. Comment.

If we consider the seawater on the surface, it comprises water and salts hence it is a homogenous mixture. If we consider the seawater from the deep sea, it consists of salts, water, mud, decayed plants etc, which will be a heterogeneous mixture.

14. While diluting a solution of salt in water, a student, by mistake, added acetone (boiling point 56°C). What technique can be employed to get back the acetone? Justify your choice.

Fractional Distillation can be used to separate acetone from the mixture of salt and water.

There are considerable differences in the boiling points of acetone (56°C) and water (100°C). When the solution is heated, acetone evaporates first. The water is collected in the distillation flask. The vapours of acetone are then condensed to obtain acetone.

15. What would you observe when

(a) a saturated solution of potassium chloride prepared at 60°C is allowed to cool to room temperature?

(b) an aqueous sugar solution is heated to dryness>

(c) a mixture of iron filings and sulphur powder is heated strongly?

a) Sodium potassium chloride will separate from the saturated solution when the temperature of the solution is reduced from 60°C to room temperature. The solubility of the solid state is affected by the change in temperature. b) When aqueous sugar solution is heated, first water gets evaporated up to some extent then sugar gets charred. c) Iron combines with sulphur and forms iron sulphide (FES).

16. Explain why particles of a colloidal solution do not settle down when left undisturbed, while in the case of a suspension, they do.

The size of the particles in suspension is relatively larger than the size of the particles in a solution. Moreover, in suspension, molecular interaction is weaker to keep the molecules in suspended form. Hence the particles settle down. Similarly, in colloidal solution, molecular interaction is strong hence they remain in suspended form.

17. Smoke and fog are both aerosols. In what way are they different?

Both smoke and fog have gas as the dispersion medium (continuous phase). But the difference lies in the dispersed phase. The dispersed phase in fog is liquid, whereas, in smoke, it is solid (particulate matter).

18. Classify the following as physical or chemical properties:

(a) The composition of a sample of steel is 98% iron, 1.5% carbon and 0.5% other elements.

(b) Zinc dissolves in hydrochloric acid with the evolution of hydrogen gas.

(c) Metallic sodium is soft enough to be cut with a knife.

(d) Most metal oxides form alkalis on interacting with water.

Answers: Physical properties are a) and c). Chemical properties are b) and d)

a) Composition of a sample of steel is 98% iron, 1.5% carbon and 0.5% other elements. It is a chemical property because no new compound is formed as steel is an alloy and alloy and is a homogeneous mixture of two or more metals or of metallic elements with non-metallic elements.

b) It is a chemical property because zinc reacts with HCL to give out zinc chloride and hydrogen gas.

c) The cutting knife will not involve any chemical reaction and did not form a new compound hence it is a physical property.

d) It is chemical property as the new compound is formed by the interaction of metal oxides with alkalis.

19. The teacher instructed three students, ‘A’, ‘B’ and ‘C’, respectively, to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). ‘A’ dissolved 50g of NaOH in 100 mL of water, ‘B’ dissolved 50g of NaOH in 100g of water, while ‘C’ dissolved 50g of NaOH in water to make 100 mL of solution. Which one of them has made the desired solution and why?

The answer is student C because both B and A have made the solution of 150 ml, whereas student C prepared the required quantity.

Students A and B prepared 150 ml solution, so student c made the desired solution because he added water to make 100 ml solution and from the calculation,

%w/v = 100 × weight of sub (solute)

volume of solution

∴ %50 = 100 × weight of sub / 100 ml

weight of sub = 50 ×100 ml / 100

∴  weight of sub = 50 g

Here the 50g NaOH required for 50% w/v 100ml solution of NaOH

20. Name the process associated with the following

(a) Dry ice is kept at room temperature and at one atmospheric pressure.

(b) A drop of ink placed on the surface of water contained in a glass spreads throughout the water.

(c) A potassium permanganate crystal is in a beaker, and water is poured into the beaker with stirring.

(d) An acetone bottle is left open, and the bottle becomes empty.

(e) Milk is churned to separate cream from it.

(f) Settling of sand when a mixture of sand and water is left undisturbed for some time.

(g) Fine beam of light entering through a small hole in a dark room illuminates the particles in its paths

Answers a) sublimation

b) Diffusion

c) Dissolution/ diffusion

d) Evaporation

e) Centrifugation

f) Sedimentation

g) Tyndall effect (Scattering of light)

21. You are given two samples of water labelled as ‘A’ and ‘B’. Sample ‘A’ boils at 100°C, and sample ‘B’ boils at 102°C. Which sample of water will not freeze at 0°C? Comment.

The answer is sample B

Sample B may consist of impurities. At 1 atm, the boiling point of water is 100°C and the freezing point is 0°C. Hence sample B, which will not boil at 102°C, will not freeze at 0°C.

22. What are the favourable qualities given to gold when it is alloyed with copper or silver for the purpose of making ornaments?

Pure gold (24 karats) is soft and does not have strength. In order to give strength to gold, silver and copper are alloyed to gold. An alloy that has 20 parts of gold and 4 parts of silver is known as 24-karat gold.

23. An element is sonorous and highly ductile. Under which category would you classify this element? What other characteristics do you expect the element to possess?

An element which is sonorous and highly ductile can be classified as metal. Other characteristics include lustre, malleability, heat and electrical conductivity.

24. Give an example, each for the mixture having the following characteristics. Suggest a suitable method to separate the components of these mixtures

(a) A volatile and a non-volatile component.

(b) Two volatile components with appreciable differences in boiling points.

(c) Two immiscible liquids.

(d) One of the components changes directly from a solid to a gaseous state.

(e) Two or more coloured constituents soluble in some solvent.

(a) Mixture of acetone and water. It can be separated by distillation.

(b) Mixture of petrol and kerosene. It can be separated by distillation.

(c) Mixture of oil and water. It can be separated by fractional distillation.

(d) Mixture of naphthalene and ammonium chloride. Separating naphthalene by filtration and then separation of ammonium chloride from water by evaporation.

(e) Mixture of pigments from a flower petal extract. It can be separated by chromatography.

25. Fill in the blanks

(a) A colloid is a ——— mixture, and its components can be separated by the technique known as ———.

(b) Ice, water and water vapour look different and display different —— properties, but they are ——— the same.

(c) A mixture of chloroform and water taken in a separating funnel is mixed and left undisturbed for some time. The upper layer in the separating funnel will be of——— and the lower layer will be that of ———.

(d) A mixture of two or more miscible liquids, for which the difference in the boiling points is less than 25 K, can be separated by the process called———.

(e) When light is passed through water containing a few drops of milk, it shows a bluish tinge. This is due to the ——— of light by milk, and the phenomenon is called ——— . This indicates that milk is a ——— solution.

a) Heterogeneous, centrifugation

b) Physical, chemically

c) Water, Chloroform

d) Distillation

e) Scattering, Tyndall effect, colloidal

26. Sucrose (sugar) crystals obtained from sugarcane and beetroot are mixed together. Will it be a pure substance or a mixture? Give reasons for the same.

It will be a pure substance because the chemical structure of the sugar remains the same despite the change in the source of their extraction.

27. Give some examples of the Tyndall effect observed in your surroundings?

• The beam of light passing on screen in a theatre.
• When light passes through a dark room.

28. Can we separate alcohol dissolved in water by using a separating funnel? If yes, then describe the procedure. If not, explain.

We cannot separate alcohol dissolved in water by separating the funnel as they both are miscible solvents.

29. On heating, calcium carbonate gets converted into calcium oxide and carbon dioxide.

(a) Is this a physical or a chemical change?

(b) Can you prepare one acidic and one basic solution by using the products formed in the above process?

If so, write the chemical equation involved

a) It is a chemical change

CaCO3+H2O →CaO+CO2

b) Acidic and basic solutions can be prepared by dissolving the products of the above process in water,

CaO+H2O → Ca(OH)2 (basic solution)  CO2 + H2O→H2 CO3 (acidic solution)

30. Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.

(a) Name a lustrous non-metal.

(b) Name a non-metal which exists as a liquid at room temperature.

(c) The allotropic form of a non-metal is a good conductor of electricity. Name the allotrope.

(d) Name a non-metal which is known to form the largest number of compounds.

(e) Name a non-metal other than carbon which shows allotropy.

(f) Name a non-metal which is required for combustion.

a) Iodine is a lustrous non-metal.

b) Bromine is liquid at room temperature

c) Graphite is an allotropic form of Carbon (non-metal), which is a good conductor of electricity.

d) Carbon is a non-metal which can form the largest number of compounds.

e) Sulphur and Phosphorous are the non-metals which show allotropy.

f) Oxygen is a non-metal which is required for combustion.

31. Classify the substances given in Fig. 2.2 into elements and compounds

Elements- Copper(Cu), Zinc(Zn), Oxygen(O2), Fluoride(F2), Mercury(Hg), Diamond

Compounds- NACL(Aq), Wood, Sand, H2O, CaCO3

32. Which of the following are not compounds?

(a) Chlorine gas

(b) Potassium chloride

(d) Iron sulphide

(e) Aluminium

(h) Carbon monoxide

(i) Sulphur powder

a.Chlorine gas

e. Aluminium

i.Sulphur powder

Long Answer Questions

33. Fractional distillation is suitable for the separation of miscible liquids with a boiling point difference of about 25 K or less. What part of the fractional distillation apparatus makes it efficient and possesses an advantage over a simple distillation process? Explain using a diagram.

The fractional column is the most important part of the fractional distillation apparatus. It is provided with glass beads in it. This column helps to obstruct the upward movement of the vapours of the two liquids. The vapours of high boiling liquid get condensed earlier at a lower level. Latent heat released helps to take the vapours of low boiling liquid to a height in the fractionating column.

The advantages are as given below:

• This method can separate the liquids with a boiling point difference of about or less than 25 K,
• During the process, both evaporation and condensation take place simultaneously.
• A mixture (like petroleum) can also be separated by the fractional distillation process, which contains several components.

(a)Under which category of mixtures will you classify alloys and why?

(b) A solution is always a liquid. Comment.

(c) Can a solution be heterogeneous?

a) An alloy is a homogenous mixture of two or more elements. Elements can be two metals or metals with non-metals.

An alloy is classified as a homogenous mixture because it shows the properties of two or more elements it is made of. Its constituents are in varied compositions. For example, brass is an alloy which shows characteristics of copper and Zinc, and their composition varies from 20 to 35 %.

b) The solution is usually a liquid, but not always. It might also include a mixture of two solids, like in alloys, and a mixture of gases, such as air.

(c) Yes, solutions can be heterogeneous.

35. Iron filings and sulphur were mixed together and divided into two parts, ‘A’ and ‘B’. Part ‘A’ was heated strongly, while Part ‘B’ was not heated. Dilute hydrochloric acid was added to both Parts and the evolution of gas was seen in both cases. How will you identify the gases evolved?

When iron fillings and sulphur is heated, it will give the following reaction

Fe(s)+S(s) → FeS

When HCl is added to this mixture, ferric chloride is produced, and Hydrogen Sulphide gas is produced. A foul rotten egg smell of Hydrogen sulphide is the indicator of H2S production.

When dilute HCL is added to setup B, Hydrogen gas is evolved, and sulphur does not take part in the reaction. When a burning matchstick is brought near the evolved gas, the matchstick burns with a pop. This is the indication of the production of Hydrogen gas.

36. A child wanted to separate the mixture of dyes constituting a sample of ink. He marked a line by the ink on the filter paper and placed the filter paper in a glass containing water as shown in Fig.2.3. The filter paper was removed when the water moved near the top of the filter paper.

(i) What would you expect to see, if the ink contains three different coloured components?

(ii) Name the technique used by the child.

(iii) Suggest one more application of this technique.

(i) If the ink contains three different coloured components, then you can observe three different bands on the paper

(ii) Child uses the technique of paper chromatography

(iii) Paper chromatography is used to separate different pigments present in the chlorophyll.

37. A group of students took an old shoe box and covered it with a black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and making another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box, as shown in Fig.2.4. They were amazed to see that milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it.

(a) Explain why the milk sample was illuminated. Name the phenomenon involved.

(b) Same results were not observed with a salt solution. Explain.

(c) Can you suggest two more solutions which would show the same effect as shown in the milk solution?

a) Milk is a colloidal substance. Particulate matter present in the milk makes the light scatter, which results in the Tyndall effect. Because of the Tyndall effect, the milk got illuminated.

b) Salt is a homogenous solution. Small particles present in salt solution do not scatter light rays hence there will be no Tyndall effect. Since the salt solution did not exhibit the Tyndall effect, light is not illuminated.

c) Detergent solution and sulphur solution exhibit the Tyndall effect.

38. Classify each of the following as a physical or a chemical change. Give reasons.

(a) Drying of a shirt in the sun.

(b) Rising of hot air over a radiator.

(c) Burning of kerosene in a lantern.

(d) Change in the colour of black tea by adding lemon juice to it.

(e) Churning of milk cream to get butter.

a) Drying of the shirt in the sun is a physical phenomenon because there are no chemical reactions or any chemical changes involved in this process.

b) Rising of hot air over the radiator is a physical change. Water in a radiator converts to vapours. Hot air becomes lighter and rises.

c) Burning of kerosene in a lantern is a chemical change because kerosene burns by using atmospheric oxygen and produces carbon dioxide.

d) Change in the colour of black tea on adding lemon juice to it is a chemical change. Lemon juice is a source of citric acid, ascorbic acid and malic acid. This acid reacts with Flavin antioxidants present in black tea to change the colour of the tea.

e) Churning of milk cream to get butter is a physical change as there is no involvement of a chemical reaction. Here, the principle is centrifugation which turns the milk cream into butter.

39. During an experiment, the students were asked to prepare a 10% (Mass/Mass) solution of sugar in water. Ramesh dissolved 10g of sugar in 100g of water while Sarika prepared it by dissolving 10g of sugar in water to make 100g of the solution. (a) Are the two solutions of the same concentration (b) Compare the mass % of the two solutions.

Mass % = Mass of solute  Mass of solute + Mass of solvent ×100

The solution made by Ramesh

Mass % = 10/ 100 +10 x 100 = 10 /110 x100 = 9.09%

Solution made by Sarika = Mass %  = 10 /100 ×100 = 10%

The solution prepared by Sarika has a higher mass % than that prepared by Ramesh.

40. You are provided with a mixture containing sand, iron filings, ammonium chloride and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture.

• Using Magnet: Move the magnet over the mixture, which will result in the sticking of iron fillings to the magnet. Like this, iron fillings get separated from the mixture.
• Sublimation: The remaining mixture is heated in a china dish. Ammonium chloride is a sublimating substance, and it will evaporate without passing through the liquid phase. Ammonium chloride can collect an inverted funnel over china-dish.
• Sedimentation, decantation and filtration: The remaining mixture is dissolved in water and allowed to settle down. Sand will settle at the bottom. The liquid should be decanted into another beaker. Then it is filtered to remove traces of sand.
• The filtered solution is heated to evaporate the water. Once all the water gets evaporated, salt remains in the beaker.

41. Arun has prepared a 0.01% (by mass) solution of sodium chloride in water. Which of the following correctly represents the composition of the solutions?

(a) 1.00 g of NaCl + 100g of water

(b) 0.11g of NaCl + 100g of water

(c) 0.0l g of NaCl + 99.99g of water

(d) 0.10 g of NaCl + 99.90g of water

which is equal to the percentage of sodium chloride in water prepared by Arun. So, option (c) is correct.

42. Calculate the mass of sodium sulphate required to prepare its 20% (mass per cent) solution in 100g of water?

Hence, the other three representations are incorrect.

Importance of Class 9 Science Chapter 2 Is Matter around Us Pure

In this chapter, the students will learn about different types of mixtures and solutions and how they can be separated from each other. Solve complex questions related to the matter around us and score good marks in the annual exam. To help students, we have provided the NCERT Exemplar Class 9 Science  Chapter 2 Is Matter Around Us Pure.

Subtopics Covered in NCERT Exemplar Class 9 Science Chapter 2 Is Matter around Us Pure

• Introduction
• What are a mixture and its types
• Solution definition and its properties
• Concentration of solution
• Definition of suspension and its properties
• Meaning of colloidal solution and its properties
• Separation of components of mixtures
• Acquiring coloured components from – black/blue ink
• Separation of cream from milk
• Separating 2 immiscible liquids
• Separating colours (dyes) in black ink
• Separating a mixture of 2 miscible liquids
• Acquiring different gases from the air
• Chemical and physical changes
• Types of pure substances
• Difference between compounds and mixtures

Students are provided with NCERT Solutions, Exemplars , sample papers, previous years’ question papers, HOTS, worksheets, tips and tricks to help them excel in their CBSE Class 9 examination and competitive examinations. To get access to the study materials of all the classes and subjects, visit BYJU’S website or download BYJU’S – The Learning App.

Frequently Asked Questions on NCERT Exemplar Solutions for Class 9 Science Chapter 2

List out the concepts discussed in chapter 2 of ncert exemplar solutions for class 9 science., is the ncert exemplar solutions for class 9 science chapter 2 the best reference guide for the students, why should i refer to byju’s ncert exemplar solutions for class 9 science chapter 2.

Leave a Comment Cancel reply

Your Mobile number and Email id will not be published. Required fields are marked *

Request OTP on Voice Call

Post My Comment

Register with BYJU'S & Download Free PDFs

Register with byju's & watch live videos.

CBSE Expert

Case Study Questions of Class 9 Science PDF Download

Download PDF Case Study Questions of Class 9 Science to prepare for the upcoming CBSE Class 9 Exams Exam 2023-24. With the help of our well-trained and experienced faculty, we provide solved examples and detailed explanations for the recently added  Class 9 Science case study questions .

Case study questions are based on real or hypothetical scenarios that require students to analyze, evaluate, and apply scientific concepts to solve problems or make informed decisions. They often present a detailed context, providing students with the opportunity to demonstrate their understanding of the subject matter beyond basic recall.

Table of Contents

Class 9 Science: Case Study Questions

The inclusion of case study questions in Class 9 science CBSE is a great way to engage students in critical thinking and problem-solving. By working through real-world scenarios, Class 9 Science students will be better prepared to tackle challenges they may face in their future studies and careers. Class 9 Science Case study questions also promote higher-order thinking skills, such as analysis and synthesis. In addition, case study questions can help to foster creativity and innovation in students. As per the recent pattern of the Class 9 Science examination, a few questions based on case studies/passages will be included in the CBSE Class 9 Science Paper. There will be a paragraph presented, followed by questions based on it.

Chapterwise Case Study Questions of Class 9 Science

• Case Study Questions for Chapter 1 Matter in Our Surroundings
• Case Study Questions for Chapter 2 Is Matter Around Us Pure?
• Case Study Questions for Chapter 3 Atoms and Molecules
• Case Study Questions for Chapter 4 Structure of Atom
• Case Study Questions for Chapter 5 The Fundamental Unit of Life
• Case Study Questions for Chapter 6 Tissues
• Case Study Questions for Chapter 7 Diversity in Living Organisms
• Case Study Questions for Chapter 8 Motion
• Case Study Questions for Chapter 9 Force and Laws of Motion
• Case Study Questions for Chapter 10 Gravitation
• Case Study Questions for Chapter 11 Work and Energy
• Case Study Questions for Chapter 12 Sound
• Case Study Questions for Chapter 13 Why do we Fall ill
• Case Study Questions for Chapter 14 Natural Resources
• Case Study Questions for Chapter 15 Improvement in Food Resources

You can find a wide range of solved case studies on cbseexperts, covering various topics and concepts. Class 9 Science case studies are designed to help you understand the application of various concepts in real-life situations.

Class 9 Science Syllabus

Unit I: Matter-Nature and Behaviour

 Definition of matter; solid, liquid, and gas; characteristics – shape, volume, density; change of statementing (absorption of heat), freezing, evaporation (cooling by evaporation), condensation, sublimation.

Nature of matter:  Elements, compounds, and mixtures. Heterogeneous and homogenous mixtures, colloids, and suspensions. Physical and chemical changes (excluding separating the components of a mixture).

Particle nature and their basic units:  Atoms and molecules, Law of Chemical Combination, Chemical formula of common compounds, Atomic and molecular masses.

Structure of atoms:  Electrons, protons and neutrons, Valency, Atomic Number and Mass Number, Isotopes and Isobars.

Unit II: Organization in the Living World

Cell – Basic Unit of life:  Cell as a basic unit of life; prokaryotic and eukaryotic cells, multicellular organisms; cell membrane and cell wall, cell organelles and cell inclusions; chloroplast, mitochondria, vacuoles, endoplasmic reticulum, Golgi apparatus; nucleus, chromosomes – basic structure, number.

Tissues, Organs, Organ System, Organism:  Structure and functions of animal and plant tissues (only four types of tissues in animals; Meristematic and Permanent tissues in plants).

Unit III: Motio n, Force,  and Work

Motion:  Distance and displacement, velocity; uniform and non-uniform motion along a straight line; acceleration, distance-time and velocity-time graphs for uniform motion and uniformly accelerated motion, elementary idea of uniform circular motion.

Force and Newton’s laws:  Force and Motion, Newton’s Laws of Motion, Action and Reaction forces, Inertia of a body, Inertia and mass, Momentum, Force and Acceleration.

Gravitation:  Gravitation; Universal Law of Gravitation, Force of Gravitation of the earth (gravity), Acceleration due to Gravity; Mass and Weight; Free fall. Floatation: Thrust and Pressure. Archimedes’ Principle; Buoyancy.

Work, Energy and Power:  Work done by a Force, Energy, power; Kinetic and Potential energy; Law of conservation of energy (excluding commercial unit of Energy).

Sound: Nature of sound and its propagation in various media, speed of sound, range of hearing in humans; ultrasound; reflection of sound; echo.

Unit IV: Food Production

Plant and animal breeding and selection for quality improvement and management; Use of fertilizers and manures; Protection from pests and diseases; Organic farming.

Books for Class 9 Science Exams

Benefits of Case Study Questions

• Enhancing Analytical Skills : Case study questions challenge students to analyze complex scenarios, identify relevant information, and derive meaningful insights. By engaging with these questions, students develop critical analytical skills that are essential for scientific thinking and problem-solving.
• Promoting Critical Thinking : Case study questions encourage students to think critically and evaluate different perspectives. They require students to reason, make logical deductions, and justify their answers with supporting evidence. This process helps in honing their critical thinking abilities, enabling them to approach problems from multiple angles.
• Encouraging Practical Application of Concepts : By presenting real-world or hypothetical situations, case study questions promote the application of scientific concepts in practical scenarios. This application-based approach fosters a deeper understanding of the subject matter and helps students see the relevance of what they learn in the classroom to everyday life.

Case study questions of Class 9 Science provide students with an opportunity to apply their knowledge, enhance analytical skills, and think critically. By understanding the format, benefits, and effective strategies for answering case study questions, students can excel in this form of assessment. While challenges may arise, practicing time management, improving information extraction skills, and enhancing observation abilities will enable students to overcome these obstacles and perform well. Embracing case study questions as a valuable learning tool can contribute to a holistic understanding of scientific concepts and foster problem-solving abilities.

1. What is the purpose of case study questions in Class 9 Science?

Case study questions serve the purpose of evaluating a student’s understanding of scientific concepts, their ability to apply knowledge in real-life situations, and their analytical and critical thinking skills.

2. How can case study questions help improve analytical skills?

Case study questions require students to analyze complex scenarios, identify relevant information, and derive meaningful insights. Regular practice with such questions can significantly enhance analytical skills.

3. Are case study questions difficult to answer?

Case study questions can be challenging due to their comprehensive nature and the need for critical thinking. However, with practice and effective strategies, students can develop the skills necessary to answer them effectively.

Leave a Comment Cancel reply

Save my name, email, and website in this browser for the next time I comment.

Download India's best Exam Preparation App Now.

Key Features

• Revision Notes
• Important Questions
• Previous Years Questions
• Case-Based Questions
• Assertion and Reason Questions

No thanks, I’m not interested!

• CBSE Class 9 Study Material

CBSE Class 9 Science Important Case Study Questions with Answers for Term 2 Exam 2022 (PDF)

Check important case study questions of cbse class 9 science to prepare for the cbse term 2 exam 2022. all these questions have been put together by subject experts..

CBSE Class 9 Term 2 Exam 2022:  Important case based questions for CBSE Class 9 Science are provided here students to prepare for the upcoming Term 2 Exam 2022. All the questions provided below are curated by the subject experts. These questions are really helpful to revise important concepts and prepare the case study questions for the exam. Answers to all questions have been provided for reference. So, students should practice the chapter-wise questions to clearly understand the right way to attempt the case based questions. Download the chapter-wise questions in PDF.

Check some of the important case study questions below:

Q. Read the following and answer the questions :

A student was asked by his teacher to verify the law of conservation of mass in the laboratory. He prepared 5% aqueous solutions of NaCl and Na 2 SO 4 . He mixed 10 mL of both these solutions in a conical flask. He weighed the flask on a balance. He then stirred the flask with a rod and weighed it after sometime. There was no change in mass.

• Was the student able to verify the law of conservation of mass?
• If not, what was the mistake committed by him?
• In your opinion, what he should have done?
• What is the molar mass of Na 2 SO 4 ?
• No, he could not verify the law of conservation of mass in-spite of the fact that there was no change in mass.
• No chemical reaction takes place between NaCl and Na 2 SO 4 . This means that no reaction actually took place in the flask.
• He should have performed the experiment by using aqueous solutions of BaCl 2 and Na 2 SO 4 . A chemical reaction takes place in this case and a white precipitate of BaSO 4 is formed.
• Will the weight of the precipitate be the same as that of the reactants before mixing?
• If not, what she should have done?
• Which law of chemical combination does this support?
• State the law of conservation of mass.
• No, it will not be the same.
• She should have weighed the total contents of the beaker after the reaction and not the precipitate alone.
• It supports the law of conservation of mass.
• Mass can neither be created nor destroyed during a chemical reaction.

Get here latest School , CBSE and Govt Jobs notification and articles in English and Hindi for Sarkari Naukari , Sarkari Result and Exam Preparation . Download the Jagran Josh Sarkari Naukri App .

• CTET Result 2024
• CSIR NET Life Sciences Exam Analysis 2024
• AFCAT Admit Card 2024
• CTET Answer Key 2024
• RRB JE Recruitment 2024
• CTET Result 2024 FAQs
• SSC CHSL Answer Key 2024
• OSSC CHSL Answer Key 2024
• India Post GDS Cut Off
• Education News
• CBSE Study Material
• CBSE Class 9

Latest Education News

Today’s School Assembly Headlines (1st August): Nitin Gadkari Attends Iran President's Oath Ceremony, Sri Lanka will hold presidential election on September 21, Paris Olympics 2024

Math Puzzle: Only 5% of people with a high IQ can solve this math puzzle in 7 seconds!

Dr MGR Medical University Result 2024 OUT at tnmgrmu.ac.in; Direct Link to Download UG and PG Marksheet

IBPS PO Recruitment Notification 2024: Check Exam Details, Qualification and Latest Updates

Brain Teaser: Only High IQs Can Solve This Dessert Equation Challenge Before the Time Limit Finishes!

Paris 2024 Olympics Medal Tally: किस देश ने जीते सर्वाधिक पदक, किसके नाम सर्वाधिक गोल्ड, यहां देखें पूरी लिस्ट

Paris Olympics 2024: पेरिस ओलंपिक्स में मेडल के साथ मिल रहे मिस्ट्री बॉक्स में क्या है? जानें

[Latest] Paris 2024 Olympics Medal Tally India: पेरिस में किन भारतीयों ने जीते पदक, यहां देखें पूरी लिस्ट 

Paris 2024 Olympics Hockey: Final Results, Schedule and Medal Tally

What is a Provisional Candidature in UPSC and How to Avoid Your Cancellation? Details Here!

CTET Result 2024 OUT at ctet.nic.in: Download July Scorecard with Roll Number, Check Marksheet Link

Preeti Sudan a Former Union Health Secretary to Replace Manoj Soni as UPSC Chairperson

NEET PG City Intimation Slip 2024 Today, Details on Registered Email IDs

NEET PG City Intimation Slip 2024: NBEMS NEET City Allotment Today at nbe.edu.in, Check Direct Link and Admit Card Date Here

West Bengal WBCHSE Class 12 Maths Syllabus 2024-25: Download PDF for Exam

MSBU Result 2024 OUT at msbuexam.in, Direct Link to Download UG and PG Marksheet

Who Was Ismail Haniyeh? A Look at His Life

Assam Board Class 10 Computer Science (E) Syllabus 2024-25: Download Subject Syllabus PDF For Free!

mpresults.nic.in MPBSE Supplementary Result 2024 Declared: Official Website Link to Check MP Board Class HSC, HSSC Results Online, Download Scorecard PDF

[OUT] mpbse.nic.in Supplementary Result 2024: एमपी बोर्ड सप्लीमेंट्री 10वीं, 12वीं रिजल्ट जारी, ये रहा Direct Link

MCQ Questions for Class 9 Science: Ch 2 Is Matter Around Us Pure

Contact Form

• Skip to main content
• Skip to secondary menu
• Skip to primary sidebar
• Skip to footer

Learn Insta

RD Sharma Solutions , RS Aggarwal Solutions and NCERT Solutions

HOTS Questions for Class 9 Science Chapter 2 Is Matter Around Us Pure

November 16, 2023 by Prasanna

These Solutions are part of HOTS Questions for Class 9 Science . Here we have given HOTS Questions for Class 9 Science Chapter 2 Is Matter Around Us Pure.

Question 1. A house wife churned full cream with a milk churner

• What will she observe after churning the milk ?
• What could be the possible reason for the observation ?
• Churning of milk is a centrifugation process. As a result, lighter particles of cream or butter will move upwards and collect at the top. Heavier residual particles will remain at the bottom. This is a very common process used to separate cream from milk or butter from yogurt.
• The separation is based on the principle that lighter particles move upwards while denser particle downwards upon centrifugation.

More Resources

• HOTS Questions for Class 9 Science
• NCERT Solutions for Class 9 Science
• Value Based Questions in Science for Class 9
• NCERT Exemplar Solutions for Class 9 Science
• Previous Year Question Papers for CBSE Class 9 Science

• Which solid dissolves best in water at 20°C ?
• Which solid is maximum soluble in alcohol ?
• Which solid is insoluble in all the three solvents ?
• Sugar is best soluble in water at 20°C
• Iodine is maximum soluble in alcohol.
• Chalk is insoluble in all the three solvents.

Question 4. Some solids dissolve easily in liquids while the others donot

• What is the name given to the liquids which dissolve solids ?
• What is the name given to the clear liquid formed when a solid dissolves in a liquid ?
• What is the name given to the liquid which contains in it some suspended particles ?
• The liquids are known as solvents
• The clear liquid is called solution or true solution. .
• The liquid is known as dispersion medium or dispersing medium.

Question 5. Butter is an example of one type of colloidal solution. Name it. Give a reason for your choice. Answer: The colloidal solution is an example in which solid acts as the dispersion medium while liquid as the dispersed phase. It is also called gel. Reason for the choice. On pressing butter, liquid drops come out of it leaving behind a solid. This clearly shows that butter is a gel.

Question 6.

• The solubility of sodium chloride in water increases with rise in temperature while that of lithium carbonate decreases. Assign reason.
• Water containing 88-8% oxygen and 11-2% hydrogen is often used as a fire extinguisher. Can a mixture containing the two gases in the same ratio by mass be used for extinguishing fire ?
• The melting point of a solid when determined experimentally comes out to be 160°C. But its actual melting point as given in standard books is 150°C. Predict the nature of the solid.
• When sodium chloride is dissolved in water, the process is endothermic in nature. This means that heat energy is absorbed in the process. Therefore, solubility increases with rise in the temperature. In case of lithium carbonate, the process of dissolution is exothermic. This means that heat is evolved in the process. Therefore, its solubility in water decreases with rise in temperature.
• No, it cannot be used. Actually, in water the two elements are chemically combined with each other. They therefore, lose their identity. But in the mixture, no chemical combination between hydrogen and oxygen has taken place. Even water cannot be formed on mixing the gases. Therefore, the mixture does not extinguish any fire.
• Since the experimentally determined melting point of the solid is more than the standard value of the melting point, this means that the solid is not in pure state. It has some impurities present. Please note that the purity of a solid can be determined by finding its melting point and comparing it with the standard value.

Hope given HOTS Questions for Class 9 Science Chapter 2 Is Matter Around Us Pure are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.