Looking for reliable SEBA Class 9 Science Chapter 2 (Is Matter Around Us Pure) extra questions and answers for the 2026–27 academic year? Access essential additional practice questions, solution concentration numerical sets, Tyndall effect comparisons, short conceptual notes, and high-yield exam questions designed to help you score top marks in your annual exams.
Extra question and answer
1. What does “pure” mean in science?
Ans. In science, a pure substance means a material that contains only one kind of particle throughout its structure.
2. Give an example of a mixture.
Ans. Milk is a common example of a mixture because it contains water, fat, and protein combined together.
3. What is a mixture?
Ans. A mixture is a combination of two or more pure substances that are physically combined without chemical bonding.
4. What is a homogeneous mixture?
Ans. A homogeneous mixture is a mixture that maintains a uniform composition throughout its entire volume, such as a sugar solution.
5. What is a heterogeneous mixture?
Ans. A heterogeneous mixture is a mixture that has a non-uniform composition in different parts, such as muddy water.
6. What is a solution?
Ans. A solution is a homogeneous mixture formed by two or more substances dissolved together.
7. Name the solvent in sugar solution.
Ans. Water acts as the solvent in a sugar solution.
8. Name the solute in sugar solution.
Ans. Sugar acts as the solute in a sugar solution.
9. Give an example of a colloid.
Ans. Milk, fog, and smoke are common examples of a colloid.
10. Give an example of a suspension.
Ans. Muddy water and chalk powder mixed in water are standard examples of a suspension.
SEBA Class 9 Science Chapter 2 Extra Questions
11. Can a solution scatter light?
Ans. No, a true solution cannot scatter light because its solute particles are too small to reflect light beams.
12. Can a suspension be separated by filtration?
Ans. Yes, the particles of a suspension can be easily separated using simple filtration.
13. Can a colloid settle down on standing?
Ans. No, colloidal particles remain suspended continuously and do not settle down when left undisturbed.
14. What is Tyndall effect?
Ans. The Tyndall effect is the scattering of a beam of light as it passes through colloidal particles.
15. Define physical change.
Ans. A physical change is a process that alters the appearance or physical state of a substance without producing a new chemical substance.
16. Give an example of a physical change.
Ans. The melting of ice into water is an example of a physical change.
17. Define chemical change.
Ans. A chemical change is a reaction in which one or more new substances with entirely different properties are formed.
18. Give an example of a chemical change.
Ans. The burning of paper is an example of a chemical change because it forms ash and smoke.
19. What is an element?
Ans. An element is a basic form of matter that cannot be broken down into simpler substances by chemical reactions.
20. What is a compound?
Ans. A compound is a substance composed of two or more elements chemically combined in a fixed proportion.
Class 9 Science Chapter 2 Important Questions SEBA 2026-27
21. Differentiate between homogeneous and heterogeneous mixtures.
Ans. A homogeneous mixture has a uniform composition throughout, such as a sugar solution, whereas a heterogeneous mixture has a non-uniform composition with distinctly visible parts, such as muddy water.
22. Differentiate between solute and solvent.
Ans. A solute is the component present in a smaller amount that gets dissolved, while a solvent is the component present in a larger amount that dissolves the solute.
23. Name two properties of a solution.
Ans. A solution is a homogeneous mixture whose solute particles are too small to be seen with the naked eye and do not settle down when left undisturbed.
24. Name two properties of a suspension.
Ans. A suspension is a heterogeneous mixture whose particles are large enough to be visible to the naked eye and settle down at the bottom over time.
25. Name two properties of a colloid.
Ans. A colloid is a heterogeneous mixture with medium-sized particles that do not settle down and are capable of scattering a beam of light to show the Tyndall effect.
26. Explain why milk appears homogeneous but is a colloid.
Ans. Milk appears uniform to the naked eye, but it is actually a colloidal mixture because tiny fat droplets are dispersed throughout water, which can scatter light to demonstrate the Tyndall effect.
27. Explain why muddy water is a suspension.
Ans. Muddy water is classified as a suspension because its soil particles are large, clearly visible, scatter light, and gradually settle to the bottom when the mixture is left standing.
28. Differentiate between mixture and compound.
Ans. A mixture consists of elements or compounds physically mixed together in variable proportions and retains the individual properties of its components, whereas a compound is formed by elements chemically combined in a fixed ratio, resulting in entirely new properties.
30. What is saturated solution?
Ans. A saturated solution is a solution in which no more solute can be dissolved at a specific temperature.
30. What is unsaturated solution?
Ans. An unsaturated solution is a solution that contains less solute than its maximum capacity and can still dissolve more solute at a given temperature.
Is Matter Around Us Pure Class 9 SEBA Extra Question Answer
31. How does cooling a saturated solution affect solute?
Ans. Cooling a saturated solution decreases the solubility of the solute, causing the excess dissolved solute to separate out in the form of solid crystals.
32. Define mass by mass % concentration.
Ans. Mass by mass percentage concentration is defined as the mass of the solute in grams dissolved per 100 grams of the total solution.
Formula: Mass by mass % = (Mass of solute / Mass of solution) * 100
33. Define mass by volume % concentration.
Ans. Mass by volume percentage concentration is defined as the mass of solute in grams present in 100 milliliters of the total solution.
Formula: Mass by volume % = (Mass of solute / Volume of solution) * 100
34. Define volume by volume % concentration.
Ans. Volume by volume percentage concentration is defined as the volume of liquid solute present in 100 units of volume of the total solution.
Formula: Volume by volume % = (Volume of solute / Volume of solution) * 100
35. Give one example of physical change and chemical change together.
Ans. The burning of a candle represents both physical and chemical changes occurring together, as the melting of solid wax is a physical change, while the burning of wax vapor into carbon dioxide and heat is a chemical change.
36. State two properties of metals.
Ans. Metals are lustrous, highly malleable, ductile, and excellent conductors of heat and electricity.
37. State two properties of non-metals.
Ans. Non-metals are poor conductors of heat and electricity, non-malleable, non-ductile, and display a variety of different colors.
38. What are metalloids?
Ans. Metalloids are elements that possess intermediate properties, showing characteristics of both metals and non-metals, such as boron, silicon, and germanium.
39. Give two examples of compounds.
Ans. Water (H2O) and common salt (NaCl) are two standard examples of chemical compounds.
40. Give two examples of elements.
Ans. Oxygen, carbon, gold, and iron are primary examples of elements.
SEBA Class 9 Science Chapter 2 Practice Notes
41. Explain the difference between solution, colloid, and suspension with one example each.
Solution: homogeneous, particles very small, do not scatter light, e.g., sugar water.
Colloid: heterogeneous, medium-sized particles, scatter light (Tyndall effect), stable, e.g., milk.
Suspension: heterogeneous, large particles, scatter light, settle down, e.g., muddy water.
42. Explain why air is a solution.
Ans. Air is considered a solution because it is a homogeneous mixture of various gases—such as nitrogen, oxygen, and carbon dioxide—that are uniformly distributed and cannot be distinguished separately.
43. Explain why milk does not settle.
Ans. Milk does not settle because the suspended fat droplets and protein particles are small enough to remain permanently dispersed throughout the liquid, making it a stable colloidal system.
44. Describe physical change with three examples.
Ans. A physical change is a process that alters the physical form or state of a substance without producing a new chemical substance. Examples include the melting of ice, the breaking of glass, and the dissolving of table salt in water.
45. Describe chemical change with three examples.
Ans. A chemical change is a reaction in which one or more new substances with entirely different chemical properties are formed. Examples include the burning of paper, the rusting of iron, and the cooking of food.
46. Explain how a mixture can be separated by physical methods with examples.
Ans. Mixtures are physically combined and can be separated using methods based on differing physical properties. For example, salt can be recovered from water using evaporation, iron filings can be separated from sand using a magnet, and butter can be extracted from curd by churning.
47. Explain sublimation and give two examples.
Ans. Sublimation is the physical phase transition where a solid substance changes directly into a gas state without passing through an intermediate liquid state. Common examples include camphor, naphthalene balls, and dry ice.
48. Explain deposition with one example.
Ans. Deposition is the phase transition in which a gas transforms directly into a solid state without first becoming a liquid. A common natural example is the formation of frost on cold surfaces during sub-zero temperatures.
49. Explain why solution does not scatter light but colloid does.
Ans. A true solution does not scatter light because its solute particles are smaller than 1 nanometer and allow light to pass through unimpeded, whereas a colloid contains medium-sized particles that are large enough to deflect light beams and cause the Tyndall effect.
50. Explain concentration terms: dilute and concentrated solution.
Ans. A dilute solution contains a relatively small amount of dissolved solute in a given volume of solvent, whereas a concentrated solution contains a relatively large amount of dissolved solute in the same volume of solvent.
Class 9 Science Pure Matter Important Questions
51. Explain difference between pure substance and mixture.
Ans. A pure substance consists of only one single type of constituent particle with a fixed composition, whereas a mixture consists of two or more distinct pure substances physically combined in variable proportions.
52. Explain why some mixtures are called heterogeneous.
Ans. Some mixtures are called heterogeneous because their individual components do not mix uniformly and remain visually distinct throughout the volume.
53. Explain why some mixtures are called homogeneous.
Ans. Some mixtures are called homogeneous because their constituent particles blend uniformly at the molecular level and cannot be seen or separated individually by simple observation.
54. Explain one example where physical and chemical changes occur together.
Ans. A classic example is a burning candle, where the melting of solid candle wax into liquid wax is a physical change, while the simultaneous burning of wax vapor to produce carbon dioxide, water vapor, and heat is a chemical change.
55. Explain why oil and water form a heterogeneous mixture.
Ans. Oil and water form a heterogeneous mixture because oil is immiscible in water, causing the two liquids to separate into distinct layers with clearly visible boundaries.
56. Describe how ammonium chloride can be separated from salt.
Ans. Ammonium chloride can be separated from common salt using sublimation; upon heating, ammonium chloride sublimes directly into vapor and condenses on a cool surface, leaving the non-sublimable salt behind.
57. Describe how pigments can be separated from petals.
Ans. Pigments can be extracted from flower petals using paper chromatography, where a suitable solvent moves up the filter paper and separates the different pigments based on their varying solubilities.
58. Explain why sweat cools our body.
Ans. Sweat cools the body because as liquid perspiration evaporates from the skin, it absorbs latent heat of vaporization directly from the body surface, resulting in a temperature drop.
59. Explain why dry ice never becomes liquid.
Ans. Solid carbon dioxide (dry ice) never turns into a liquid under normal atmospheric pressure because it sublimes directly into gaseous carbon dioxide as it absorbs heat.
60. Explain why metals are sonorous.
Ans. Metals are sonorous because their closely packed crystalline structures and strong metallic bonds allow vibrational waves to propagate smoothly across the lattice, producing a ringing sound when struck.
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