Important Questions for CBSE Class 9 Science Chapter 2 – Is Matter Around Us Pure
Science is an interesting subject however, it has some new concepts which are difficult to comprehend. Thus, students will have to make extra effort to understand the concepts of Physics, Chemistry, and Biology. In addition, the students will have to understand the various Important Questions for Class 9 Science Chapter 2 so that students will get an idea of what to expect in their upcoming exams. Furthermore, it will prepare them for the Class 10 board exams. Practising Science Class 9 Chapter 2 important questions will enhance the understanding of the chapter and boost the students’ confidence level.
At Extramarks, we highlight key concepts and questions from each chapter which help students revision and thorough preparation ahead of their examinations. By solving the important questions in Class 9 Science Chapter 2, the students will be more familiar with the questions asked in final exams. Science is a subject which requires deep conceptual understanding, so memorising the answers especially in Science will not always fulfil the purpose.
So, while solving important questions, students must have the clarity of the concept and clear their doubts through exercise questions. For this, we have compiled questions from the NCERT textbook, NCERT exemplar, and other reference books. It also has questions from past year’s exam papers. Students can solve important questions in Class 9 Science Chapter 2 to lay a strong foundation for the chapter.
Students should also try to understand the answer writing skills better. They can practise diagrams, which they can find in the CBSE sample papers and the CBSE revision notes. Students can register on the Extramarks website and access our complete set of important questions for Class 9 Science Chapter 2.
Students can also refer to a repository of study material on our Extramarks website, including NCERT solutions, NCERT books, and past year questions papers.
Get Access to CBSE Class 9 Science Important Questions 2022-23 with Solutions
Also, get access to CBSE Class 9 Science Important Questions for other chapters too:
|CBSE Class 9 Science Important Questions|
|Sr No||Chapters||Chapter Name|
|1||Chapter 1||Matter in Our Surroundings|
|2||Chapter 2||Is Matter Around Us Pure|
|3||Chapter 3||Atoms and Molecules|
|4||Chapter 4||Structure of Atom|
|5||Chapter 5||The Fundamental Unit of Life|
|7||Chapter 7||Diversity in Living Organisms|
|9||Chapter 9||Force and Laws of Motion|
|11||Chapter 11||Work and Energy|
|13||Chapter 13||Why Do We Fall ill|
|14||Chapter 14||Natural Resources|
|15||Chapter 15||Improvement in Food Resources|
Is Matter Around Us Pure Class 9 Important Questions with Answers
Q1. Write down the steps that you would take to make tea. You can use the following words: solution, solvent.
Answer: Begin by heating the water in a saucepan. Next, add some sugar to dilute the solvent. After the solute has wholly dispersed in the solvent, you will get the proper solution. Next, add insoluble tea leaves along with another soluble liquid. The solution should be heated to boiling point. After boiling the solvent , filter the solution with a sieve.
Q2. What is a colloid? What are its different properties?
Colloids are heterogeneous mixtures of substances. They have a particle size too small to be visible by naked eyes.
Answer: (1) Although heterogeneous, it appears to be homogeneous.
(2) Particles are too small to be visible by naked eyes.
(3) They scatter the light that passes through them to make it visible.
(4) The colloid particles don’t settle down if they are left alone.
Q3. Which statement about alloys is true?
(i) An alloy may be made from a combination of more than one metal.
(ii) An alloy combines a metal or a nonmetal.
(iii). An alloy can’t be separated into its components using physical methods.
Answer: (ii) An alloy combines a metal or a nonmetal.
Alloys can be made up of mixtures of metals and nonmetals. Physical methods cannot separate them. An alloy can still be considered a mixture, as it shows the properties and composition of its constituents. Brass, for example, is composed of about 30% zinc and 70% copper.
Q4. Describe the following examples.
(a) Saturated solution
Ans: This solution is one in which no other solute particles are dissolved at a given temperature.
(b) Pure substance
Ans: A substance with a fixed composition composed of one type of particle is called a “fixed” substance.
Ans: A substance with a fixed composition composed of one type of particle is called a “fixed mixture.” It is a heterogeneous solution/mixture in which the particle size ranges from 11 to 10001000. This is an intermediate between suspensions and accurate solutions. Colloids can be divided into dispersion media and dispersed phases.
Ans: This is a heterogeneous mixture in which dispersion particles and insoluble solid particles remain suspended within the medium.
Q5. Fog is one of the most common colloids.
(a) Dispersed phase is liquid and dispersing medium gas
(b) Dispersed phase is a solid and dispersing medium gas
(c) Dispersed phase is a gas and dispersing medium, a liquid
(d) Dispersed phase is liquid and dispersing medium liquid
(a) Dispersed phase is liquid and dispersing medium gas
Q6. How do you separate petrol and kerosene from each other (differences in their boiling points are more significant than 25 degree celsius?
The question states that petrol and kerosene are miscible, and their boiling points differ by more than 25 degrees Celsius. Therefore simple distillation can separate them. Because their boiling points are different, distillation can separate petrol and kerosene.
The mixture of petrol and kerosene will be put into a hot distillation flask. The boiling point of petrol is lower, so it will evaporate first and then create vapours as the mixture heats up. The condenser collects the gasoline vapours and condenses them. Kerosene with higher boiling points will be left behind in the distillation flask.
Their vapours will form within the same temperature range, even if there is a slight difference in the boiling points. This means that a simple distillation process cannot be used to separate them. Fractional distillation is used to separate these liquids. The vapours are passed through a fractionating column, and then condensation occurs.
Q7. Name the methods used to separate these:
(a) Butter made from curd.
(b) Salt made from seawater
(c) Camphor made from salt
- a) A process called centrifugation can be used to separate butter and curd. The principle of density guides this process.
- b) You can use simple evaporation techniques to separate salt and seawater. The process of distillation causes water to evaporate, leaving behind solid salt. This is how salt is produced.
- c) Sublimation is a method to separate camphor and salt. During the phase change, camphor does not experience a liquid phase.
Q8. What is a saturated solution?
Saturated solution: A solution where no more solid (solute) can be dissolved at any temperature is known as a saturated solution. If 50 gm is the maximum amount of a solute that can be dissolved at 298K in 100 gm, then 150 gm is the saturated solution.
Q9. Use an example to describe the pure substance.
Pure Substance: This is a pure substance composed of only one type of matter or particles. It cannot be separated from any other kind of matter using any physical process. Pure substances have the same colour and taste at any temperature or pressure. Pure water, for example, is colourless, odourless, and tasteless. It boils at 373K at normal atmospheric pressure.
Q.10 What separation techniques can you use to separate the following?
- Get sodium chloride in water.
- Ammonium chloride is obtained from a mixture of sodium chloride and ammonium chloride.
- The engine oil of a car contains small pieces of metal.
- Different pigments are extracted from flower petals.
- Butter made from curd
- Oil can be extracted from water.
- Tea leaves made from tea
- Iron pins made from sand
- Wheat grains start in the husk.
- Fine mud particles are suspended within the water.
- Evaporation: Water will evaporate, leaving behind sodium chloride.
- Sublimation: Ammonium chloride is collected as sublimate.
- Filtration: Metal pieces can be separated using filtration.
- Chromatography: The separation of pigments (coloured components) in flower plant extracts can be done by chromatography.
- Centrifugation: Butter will be separated by centrifugation.
- Separating funnel: A separating funnel can help separate oil and water.
- Filtration: After filtering through a sieve, the tea leaves are collected on the sieve.
- Magnetic separation: Iron pins will magnetise to a magnet, not sand particles.
- Sieving: Wheat grains can be separated from their husks using a sieve.
- Sedimentation: Mud particles can settle as precipitate due to sedimentation. Filtration can separate it later.
Q11. The following can be classified as physical or chemical changes:
- Tree cutting,
- Melting butter in a saucepan
- Rusting of almirah
- Boiling water to make steam
- Electric current passes through water, and water breaks down into hydrogen and oxygen gases.
- dissolve common salt in water
- make a fruit salad using raw fruits
- Wood and paper are burned
Changes in the physical body
- Tree cutting
- Melting butter in a saucepan
- Boiling water to make steam
- dissolve common salt in water
- Making a fruit salad from raw fruits
- Rusting of almirah
- Electric current passes through water, and water breaks down to hydrogen.
- Wood and paper are burned.
Q12. How can you separate salt from ammonium chloride using a method?
Sublimation can separate salt from ammonium chloride. Sublimation is a process that converts a solid substance into a gaseous form. This principle can be applied to the mixture of two because ammonium chloride transforms directly from a solid state to a gaseous one upon heating. Salt does not possess that property.
- In an inverted funnel, the mixture of NH4ClNH4Cl is placed in a china dish.
- The mixture is heated with a burner. NH4ClNH4Cl then sublimates, transforming it into vapours.
- Salt, a non-sublimely compound, settles in the inverted funnel.
- Sublimation allows for the separation of NH4ClNH4Cl salt.
Q13. Give examples to illustrate the following:
(a) Saturated solution
(b) Pure substance
(a) A saturated solution: The solution becomes saturated when the solute begins to separate from the bottom of the container at a specific temperature. Heating can cause a saturated solution to become unsaturated.
(b) Pure substance: A single substance or matter that cannot be separated from other types of matter using any physical process.
(c) Colloid: Colloidal solutions can also be heterogeneous like suspensions but have smaller particles that are distributed. It is between 1 and 100 nm, between suspension particle sizes.
(d) Suspension A suspension is a mixture of solid particles and liquid that has not dissolved. If the Suspension is not disturbed for a while, it will settle as a precipitate.
Multiple Choice Questions
Q14. A generic mixture of sulphur and carbon disulphide is considered as:-
(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.
Answer: (d) homogeneous and does not show the Tyndall effect.
Explanation: The mixture of sulphur, carbon disulfide and water is homogeneous. Carbon disulphide is used to dissolve sulphur. The Tyndall effect is caused by light scattering. The Tyndall effect is visible in colloids and suspensions that contain heterogeneous mixtures. The correct answer is (d).
Q15. The 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.
Ans: (d) iodine in alcohol A “Tincture of Iodine” solution is made by dissolving 2 – 7% iodine into the alcohol. The presence of alcohol characterises the tincture solutions because alcohol is a suitable solvent. Iodine is not soluble in water. Iodine tincture can also be used as an antiseptic. The correct answer is (d).
Q16. The process of rusting iron articles is called
(a) Corrosion is both a chemical and a physical change
(b) Dissolution and its physical change
(c) Corrosion is a chemical reaction
d) Dissolution is a chemical reaction
Answer: The correct answer is option (c) corrosion is a chemical reaction
Explanation: Iron corrosion is a chemical change. Rusting is caused by hydrated iron oxide Fe2O3, a chemical compound. NH2O is iron(III), which is different from elemental iron. These changes do not alter the substance’s identity and can be reversed.
Example: Water can be frozen to ice and melt into water. On the other hand, chemical changes are when the original substance identity has been altered and cannot be restored to its original form.
When you add solid solute to the solvent, some of the solutes will dissolve, and their concentration in the solution will increase. This is called dissolution.
Crystallisation occurs when the solution’s solute particles collide with the solid solute particles, causing them to separate from each other.
Q17. Which of these is homogeneous?
- a) (i) and (iii).
- b) (iii) and (iv)
- c) (i) and (iv)
- d) (iiii) & (iv)
Answer: The correct option is (i) and(iv).
Explanation: Ice and air are homogeneous because they are indistinguishable elements.
Q18. Which of these are chemical changes?
(i) Wood decay
(iii) Sawing of wood
(iv) The hammering of a nail into a piece of wood
(a) (i), and (ii).
(b) (ii), and (iii).
(c) (iii), and (iv).
(d) (i), and (iv).
Answer: The correct option is (a) (i) & (ii)
Explanation: Wood cannot be restored to its original state if it is decomposed or burned. The chemical composition of compounds is unchanged by physical processes such as sawing and nailing wood pieces together.
Q19. A and B were two substances that were mixed to create A2B. The reaction was 2A + B – A2B. Which of these statements regarding this reaction is incorrect?
(i) Product A2B shows the properties of substances A & B.
(ii) The product will always be of a fixed composition
(iii). The product thus formed cannot be classified as a compound.
(iv) A product is formed when it contains an element.
(a) (i),(ii) or (iii),
(b) (ii),(iiii), and (iv).
(c) (i),(iii), and (iv).
(d) (ii),(iiii), and (iv).
Answer: The correct option is (c), (i),(iii), and (iv).
The properties of compound A2B (the product that is formed from the reaction) are different from those of its constituent elements, “A” or “B”. A2B will always contain “A” or “B” in its fixed composition determined by the mass.
Q20. Which statements about species X, Y, and P are correct?
(i) P refers to a compound.
(ii) X compound and Y compound.
(iii) X and Y represent elements.
(iv) P has an exact composition.
(a) (i),(ii), and (iii).
(b) (i),(iii) or (iv).
(c) (ii),(iiii), and (iv).
(d) (i),(iii), and (iv).
Answer: The correct option is (d), (i),(iii), and (iv).
They are elements because simple chemical reactions cannot further break down (“X” or “Y”). Accordingly, (ii) is correct while (iii) is incorrect.
The product “P”, which is composed of elements “X” & “Y”, is called “P”.
Accordingly, (i) is incorrect. The compound “P” will always contain a fixed amount of the constituent elements “X” and “Y”.
Accordingly, (iv) is correct. Therefore, the correct answer is an option (d).
Q21. Please suggest the separation techniques that would be required to separate these mixtures.
(a) Mercury, water
(b) Potassium and ammonium chloride
(c) Common salt, ordinary water, and sand
(d) Kerosene oil and water, as well as salt
(a) Mercury is separated from water by decantation using a separating funnel.
The difference in the densities of two impermeable liquids determines whether a funnel can separate them. Mercury weighs more than water, so it forms the lower layer of water and is separated from the water.
(b) Potassium and ammonium are separated using sublimation methods. Ammonium chloride is a sublimate. This means that the ammonium chloride sublimes, leaving behind potassium chloride.
Sublimation leads to the transformation of a solid into vapours upon heating and then into solids upon cooling.
(c) Salt, water, and sand are separated.
(i) decanting (or filtration) is used to separate sand and standard salt solution in the water. Common salt is soluble, while sand is not. The sand is separated from the standard salt solution in water as a residue by filtration.
(ii) Common salt is separated from water by evaporation. Common salt is left behind as a residue after the water evaporates.
(d) (i). Decantation using a separating funnel separates kerosene from salt solution in the water. They form separate layers (salt in water is soluble).
Q22. Evaporation can be used to recover salt from its solution. Suggest another method.
Answer: Salt can be recovered from its solution by ‘crystallisation’. Crystallisation’ is a better technique than ‘evaporation ‘because it also removes soluble impurities, which do not get removed in evaporation.
Q23. You can classify seawater as both a homogeneous and heterogeneous mixture. Comment.
Answer: The seawater at the surface is composed of water and salts, making it a homogenous mixture. The seawater from the deep sea comprises water, salts, and mud. This will make it heterogeneous.
Q24. A student accidentally added acetone to a solution of salt and water while diluting it. (Boiling point 56 degrees celsius). How can you get the acetone back? Comment.
Answer: Distillation is possible to separate acetone and the mixture of salt/water.
Explanation: Acetone’s boiling point is 56°C, while water is 100°C. Acetone is first to evaporate when the solution is heated.. This can be collected to make acetone.
Q25. What would you observe when?
(a) A saturated potassium chloride solution at 60 degrees Celsius is allowed to cool down to room temperature.
Ans: When the temperature drops from 60°C to room temperature, the solid potassium chloride will separate from the saturated solution. Temperature changes can affect solubility.
(b) Aqueous sugar solution is heated until it reaches dryness.
Answer: Water will first evaporate when the aqueous sugar solution is heated. The sugar will become charred if the solution gets heated to dryness.
(c) A mixture such as iron filings, and sulphur powder, is heated to a high temperature.
Answer: When heated at high temperature , the iron will react chemically with the sulphur, and iron sulphide will form (FeS).
Q26. The following properties can be classified as either chemical or physical:
(a) A steel sample contains 98% iron, 1.5% carbon, and 0.5% other elements.
Ans: Steel is an alloy made of iron and about one percent carbon.
(b) Zinc is dissolved in hydrochloric acids with the formation of hydrogen gas.
Ans: Zinc is a reactive metal. It replaces hydrogen in the hydrochloric acids and forms zinc chloride.
(c) The metallic sodium is soft enough to be cut with a knife.
Ans: The physical property that sodium has is: It’s a soft metal.
(d) When metal oxides interact with water, most form alkalis.
Ans: The chemical properties of metallic oxides are: The metallic oxides react to water and form alkalies.
Q27. Name the process that is associated with the following:
(a) Dry Ice is kept at room temperatures and one-atmosphere pressure.
Answer: Through the sublimation process. The dry ice and solid carbon dioxide melt at lower temperatures to form large quantities of CO2 gas. This is dangerous and can be dangerous to handle. It can also cause burns from freezing.
(b) Ink drops are placed on the water surface in the glass.
Answer: Through the diffusion of ink into water.
(c) A potassium permanganate crystalline is placed in a beaker. Water is added to the beaker, stirring.
Answer: By the dissolution/diffusion of the potassium permanganate.
(d) An acetone bottle left open can cause it to become empty.
Answer: Through the diffusion and evaporation of the acetone.
(e) To separate the cream from milk, it is churned.
Answer: Through centrifugation.
(f) Sand settles when water and sand are left alone for a while.
Answer: Through the sedimentation of sand.
(g) A fine beam of light enters through a small hole in the darkened room and illuminates all particles.
Answer: Through the scattering light (Tyndall effect).
Q28. Each mixture component with the following characteristics should be given as an example. These mixtures can be separated using a suitable method.
(a) A volatile component and a non-volatile one.
Answer: The sodium chloride and ammonium chloride. Sublimation can be used to separate the mixture from the ammonium chloride.
(b) Two volatile compounds with significant differences in boiling points.
Ans: Acetone and water. You can either evaporate or distil the mixture. The boiling point for acetone is 56 degrees Celsius. One hundred degrees Celsius is the boiling point for water. 44 degrees Celsius is the difference between the boiling points
(c) Two immiscible liquids.
Answer: It is the kerosene mixed with water. A separating funnel can help separate the mixture.
(d) A component changes from a solid state to a gaseous one.
Answer: The ammonium chloride and potassium chloride. Sublimation of the ammonium chloride can separate the mixture.
(e) A plant’s two or three coloured constituents are soluble in a solvent.
Ans: Plant pigments. The chromatography method can separate the mixture of the coloured constituents.
Q29. (a) A colloid is a mixture of __________ and its components can be separated using the technique called __________.
Ans: Heterogeneous centrifugation.
(b) Although ice, water, and water vapour have different properties and look different, they are all _________ the same.
(c) A mixture of water and chloroform is placed in a funnel and left to stand for a while. The separating funnel’s upper layer will be of ________, while the lower layer will have __________.
Ans: Water, chloroform. (The density of water and chloroform is lower than that of water).
(d) Mixtures of more than one miscible liquid can be separated using the process called ____________.
Ans: Fractional distillation.
Q30. Explain why colloidal solutions’ particles don’t settle when left alone, but suspensions do.
Answer: The colloidal particles are small and not very heavy. They are always in a state called Brownian motion. This counters gravity’s force on colloidal particles. It also helps stabilise colloidal solutions and prevents them from settling down. Colloidal particles can also be charged and repel one another.
This does not allow colloidal solution particles to settle. Suspension particles are heavier and have less movement. They settle down because of gravity.
Q31. Nonmetals are often poor conductors for heat and electricity. They are not lustrous, non-sonorous, and non-malleable.
(a) Name a nonmetal that is lustrous.
(b) Name a metal that exists at room temperature as a liquid.
(c) A nonmetal in its allotropic state is a good conductor for electricity. Name the allotrope.
(d) Name the nonmetal most likely to make the most significant number of compounds.
(e) Name any nonmetal other than carbon that exhibits allotropy.
(f) Name a metal that is needed for combustion.
(a) Iodine can be a nonmetal that is shiny.
(b) Bromine, a nonmetal, is a liquid that exists at room temperature.
(c) Graphite, the allotropic carbon form, is a good conductor and conductor of electricity.
(d) Carbon, a nonmetal, is known to make the most compounds.
(e) Phosphorus, a nonmetal other carbon that exhibits allotropy, is called phosphate.
(f) Oxygen, a nonmetal, is necessary for combustion.
Very Short Answer Questions
Q32. What is meant by saying that nonmetals are brittle?
Answer: Nonmetals are brittle and cannot be hammered into thin sheets. They will break into smaller pieces if hammered. E.g., sulphur and phosphorus.
Q33. What is the general name of the materials which contain at least two pure substances and show the properties of their constituents?
Answer: Materials made up of two or more pure substances and showed the properties of their constituents are called mixtures.
Q34. What is the significant difference between a solution and an ordinary mixture?
Answer: A mixture is a substance that consists of two or more elements or compounds in any proportion, which might be distinct or indistinct. On the other hand, a solution is an example of a homogenous mixture, i.e., substances in the solution are entirely mixed and indistinguishable.
Q35. Please fill in these blanks with the appropriate words:
(a) A single type of element can make up an element________
(b) Brine is used as ______ and alcohol as a _______
(c) Brass is an alloy that is considered to be a __________
(d) The important metalloids are_____, _______ and _______
(e) These are the sonorous elements ________
(a) A single type of element can make up an element atom.
(b) Brine is used as a mixture and alcohol as a compound.
(c) Brass is an alloy that is considered to be a mixture.
(d) The important metalloids are boron, silicon and germanium.
(e) These are the resonant elements of metals.
Class 9 Science Chapter 2 Extra Questions and Answers – Key Topics
The chapter needs a proper comprehension of the Science concepts, and students must recall the wide range of identities they have read and understood so far.
Science defines a substance as a material that can’t be separated into other types of matter using physical techniques. Substances can be formed from one or more components that make matter. They are often mixed, and the result is inferred to be a mixture.
What is a mixture?
Mixtures can be made up of more than one type of pure matter. We know that sodium chloride dissolved can be separated from water through the physical process called evaporation. But sodium chloride, a pure substance, cannot be separated from water by any physical process into its chemical components.
Sugar is a pure substance that only contains one type of pure matter, and the composition is the same throughout. Soil and soft drinks are not one pure substance. No matter where a pure substance comes from, its characteristic properties remain the same. We can therefore say that a mixture is made up of more than one pure substance.
What is a solution?
A solution is defined as a homogeneous combination of two or more substances. There are many solutions that you will encounter in your day-to-day life. Soda water, lemonade and soda water are just a few examples. These are examples of solutions. A solution is a liquid that has a solid, liquid, or gas dissolved in it.
However, solid solutions (alloys) and gaseous solutions can be found (air). A solution is homogeneous at the particle level. Lemonade, for example, tastes the same everywhere. This is because the solution contains evenly distributed sugar and salt particles.
What is suspension?
A suspension is a mixture that contains solute particles in a heterogeneous medium. The solute particles are not dissolved but remain suspended in the bulk of the medium. The naked eye can see a suspension’s particles.
Properties of a Suspension
- Suspension can be described as a heterogeneous mix.
- The naked eye can see the particles in Suspension.
- A suspension’s particles scatter light through it, making its path visible.
- If a suspension is not disturbed, the solute particles will settle down. Filtration can separate them from the mixture. The Suspension stops scattering light and breaks when the particles settle.
Physical and Chemical Changes
We have learned about some physical properties of matter in the previous chapter. These properties can be observed and described as colour, hardness or rigidity. They also include density, melting point, boiling points, colour and density. These are physical properties. Interconversion of states can be described as a physical change. This is because the changes do not involve a change in the substance’s chemical nature or composition. Although water vapour, water, and ice have different physical properties and appearances, they are chemically the same.
Types of Pure Substances
|Elements or compounds just mix to form a mixture, and no new compound is formed.||Elements react to form new compounds.|
|A mixture has a variable composition.||The composition of each new substance is permanently fixed.|
|A mixture shows the properties of the constituent substances.||The new substance has different properties.|
|The constituents can be separated relatively easily by physical methods.||The constituents can be separated only by chemical or electrochemical reactions.|
Pure and impure substances
Pure material/substance refers to a single type of particle not subject to physical processes. Further, it has a stable structure and a constant melting and boiling point. Pure substances are elements with a fixed composition. In addition, pure materials include water, sulphur and hydrogen, carbon, diamond and other pure substances.
There are two types of pure substances such as elements and compounds. A pure substance cannot be separated into any other substances by chemical or physical methods. Dalton’s research shows that atoms are the simplest type of matter. Further, they can be described as pure substances of only one type. Some examples of elements include hydrogen, carbon, and oxygen.
An impure substance/material contains two or more types of particles that physical methods can separate. The mixtures can contain any impure combination of substances. A mixture can be either homogeneous (or heterogeneous). Some examples of mixtures include salt solution, sugar solution; milk, sugarcane juice; soft drink; sharbat; rocks, minerals, petroleum and LPG; biogas; tap water, tea, coffee, paints, woods, soil, bricks, and other beverages.
Metals, Metalloids and Nonmetals
The following are the three elements that can be divided into:
- Metals: This is a malleable, ductile element that conducts electricity. Examples of metals include iron, copper, aluminium, silver, gold and platinum.
- Nonmetals are chemical compounds or elements that lack metallic properties. They account for approximately 14% to 15% of the elements of the periodic table. Nonmetals include carbon, phosphorus and hydrogen.
- Metalloids are chemical elements that have properties between nonmetals and metals. Boron, Silicon and Bismuth are just a few examples of metalloids.
These are the properties of nonmetals and metals as compared are:
|Metals are strong and durable due to their high tensile strengths.||Nonmetals are solid and durable, but they have a moderate tensile force.|
|Metals possess a resonance quality. When struck, they produce a ringing sound.||Nonmetals don’t have a resonance quality|
|At room temperature, metals are solids.||Nonmetals can be solids, liquids or gases at room temperatures.|
|Metals are great conductors of heat and electricity.||Nonmetals have poor electrical conductors and heads.|
|Metals can be polished to make them lustrous.||Nonmetals can’t be polished.|
Mixtures and their Types
Mixtures can contain more than one type of particle. They don’t react chemically but can be physically mixed in any ratio. You can choose between homogeneous or heterogeneous mixtures.
|Mixture homogeneous||Mixture heterogeneous|
|All components are evenly mixed||The mixture is not well mixed.|
|Homogeneous mixtures are composed of one phase.||Heterogeneous mixtures are composed of more than one phase|
|Example: Sugar is dissolved in water.||Example: Air, sand, and common salt.|
Students can refer to the list of important questions in Class 9 Science Chapter 2, where we have compiled important questions based on mixtures and their types.
Solutions and Their Types
A solution is a homogeneous combination of two or more substances. Some examples of solutions are lemon water, sugar solution and soda water.
- Solvent: A component that dissolves another component in the solution. Solvents are often present in more significant quantities. Solvents can be found in water and alcohol.
- Solute: This is the part of the solution that dissolves into the solvent. It is usually present in smaller quantities. Solutes include sugar, salt, and Iodine.
Properties of solutions
- Solutions can be described as a homogeneous mix.
- The proper solution doesn’t scatter the light.
- Stability is the key to finding the solution.
- A microscope cannot see particles in a solution. The particle size is also less than 1 nm.
- It is impossible to separate the soluble particles from the mixture.
Different types of solutions
- Solid in a solid solution
- In a liquid solution, it is solid
- The liquid in a liquid solution
- Gas in a gas solution
- A liquid solution containing gas
Solubility of the solution and its concentration
- It is also known as the solubility of the solvent.
- Temperature increases the solubility of solids within liquids.
- Temperature increases affect the solubility of liquids.
- Pressure increases the solubility of gases in liquids.
- Changes in pressure do not affect the solubility of solids in liquids.
The concentration of the solution
- It is the mass of the solution in grams, defined as 100g.
- Saturated solutions can be a solution that contains no more solute at a given temperature.
- Unsaturated solutions contain more solute than can be dissolved in water without increasing temperature.
Benefits of Solving Is Matter Around Us Pure Important Questions
Students may face difficulty while understanding the complex concepts in Science. One way to tackle this is to practise important questions in Class 9 Science Chapter 2. Chapter 2 Class 9 Science important questions cover all the essential topics, and these questions are created from an exam perspective and are most likely to be asked in the exam. Solving important questions gives students a competitive edge.
Here are some of the benefits of studying important questions in Class 9 Science Chapter 2:
- Students will revise everything and cover the entire syllabus, and these questions are created by the subject experts exclusively for the exams.
- There is a higher chance that some of these questions will be asked in the exam. It gives students an overall idea of how the questions might appear in their exams and helps them exam ready and not get unnecessarily stressed or anxious.
- The comprehensive guide for essential questions puts together all these questions and helps students prepare well for the annual exams.
- It provides a deep understanding of concepts and helps them prepare for their exams in a balanced manner.
- The questions for each chapter in the textbook are mentioned in this list.
- The list of essential questions in Class 9 Science Chapter 2 consists of objective types, and short and long answers.
- This list covers all the essential questions covered in this chapter and will guide students on how to solve them.
- Directions are detailed while solving these important questions in Class 9 Science Chapter 2.
- The chapter is divided into different sections. Each section is further subdivided into objective type, short answer, long answer, etc.
- The solutions provided offer details of the practicalities required in clearing the question paper, which can benefit students during final exam preparation and their future prospects.
Extramarks is one of the leading online learning platforms that offer comprehensive learning solutions to students in Classes 1 through 12. We also offer additional study and course materials. To access the most essential resources, students can also click on the links below:
Q.1 Complete the table:
Q.2 Justify the given statements.
a. Epidermal cells absorb water for the plant.
b. Cutin is like sunscreen for a desert plant.
c. Cork consists of dead cells.
a. Epidermal cells are present in the root and other parts of the plants. Epidermal cells, as part of the roots, help in the absorption of water from the soil.
b. Cutin is the thick waxy coating that is present on the surface of the desert plants. It protects them against the excessive removal of the water from the plant in the presence of sunlight. Similarly, sunscreen protects the human skin from sunlight.
c. The cork cells lose the protoplast on maturity. Therefore, the cells of cork are the dead cells.
FAQs (Frequently Asked Questions)
1. Is the list of essential questions in Class 9 Science Chapter 2 enough to score good marks?
The solutions we provide are concise and written from an examination perspective. The answers to exercise questions are clearly explained with examples and which are 100% accurate. These solutions will help students prepare for the exam as we follow the guidelines provided by NCERT Book and CBSE Science Syllabus. These solutions will assist students by solving these questions and strengthening their understanding of the key concepts in an easy-to-understand language. Further, this exercise covers all solved exercises and practice questions to speed up their preparation and come out with flying colours.
2. Why does water act as a compound and not a mixture? Explain.
Water is a compound since it contains two components, oxygen and hydrogen. Electrolysis can separate the two constituents. They are combined in a fixed ratio of 1:2. The ratio of oxygen and hydrogen is set and cannot be changed. Therefore, it is difficult to separate water constituents easily. These can only be separated using a unique process called electrolysis.
3. What are the salient features of important questions in Class 9 Science Chapter 2 from Extramarks?
The list of Important questions in Class 9 Science Chapter 2 can help students score high marks in the exams. These questions can be found on our Extramarks website. Students can use these important questions to help them understand the concepts and revise them thoroughly so that they can answer any question with ease. Subject matter experts have prepared them, students can practise all the important questions available on Extramarks to prepare for exams.