CBSE Important Questions Class 9 Science Chapter 2: Here are the important questions of is matter around us pure class 9 for CBSE Class 9 students. Practicing these questions will help students solidify their understanding of key concepts, such as mixtures, solutions and the separation of substances. By regularly working through these problems, students can enhance their problem-solving skills, grasp fundamental ideas more effectively and perform better in exams. This practice is important for reinforcing theoretical knowledge and ensuring thorough preparation for CBSE exams.
These class 9 science chapter 2 important questions are essential to master the chapter well. Students looking for is matter around us pure important questions and class 9 chapter 2 science important questions will find this content very useful.
CBSE Important Questions Class 9 Science Chapter 2 Overview
These questions are created by subject experts of Physics Wallah for CBSE Class 9 Science Chapter 2 Is Matter Around Us Pure?. By practicing these questions, students can improve their conceptual clarity and develop a stronger understanding of the chapter. The expert created questions help students focus on key areas and prepare effectively for their exams.Is Matter Around Us Pure Class 9 Science Important Questions Answers
Here we have provided CBSE Important Questions Class 9 Science Chapter 2 Is Matter Around Us Pure?-Multiple Choice Question (1 Mark)
1. 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)
2. A change in the physical state can be brought about:
(A) When energy is either given to or taken out from the system
(B) Without any energy change
(C) Only when energy is taken out from the system
(D) Only when energy is given to the system
Ans: (A)
3. Tyndall effect is observed in which one of the following?
(A) True solution
(B) Starch + water
(C) Alum + water
(D) NaCl + water
Ans: (B)
4. Which of the following are homogeneous in nature?
(i) Alloy
(ii) Wood
(iii) Soil
(iv) Air
(A) (iii) and (iv)
(B) (i) and (iii)
(C) (i) and (iv)
(D) (ii) and (iv)
Ans: (C)
5. 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) Dissolution and it is a chemical change
(D) Corrosion and it is a chemical change
Ans: (D)
6. Which of the following is an example of metalloids?
(A) Oxygen
(B) Chlorine
(C) Carbon
(D) Silicon
Ans: (D)
7. 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)
8. Which of the following is an example of pure substance?
(A) Brick
(B) Wood
(C) Iron
(D) Alloy
Ans: (C)
9. An example of a colloid is:
(A) Air
(B) Milk
(C) Salt solution
(D) Salad bowl
Ans: (B)
10. Two chemical substances 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 statements are correct?
(i) P is a compound
(ii) X and Y are compound
(iii) X and Y are elements
(iv) P has a fixed composition
(A) (i), (ii) and (iii)
(B) (i), (ii) and (iv)
(C) (ii), (iii) and (iv)
(D) (i), (iii) and (iv)
Ans: (D)
11. Assertion: The amount of the solute present in the saturated solution at the given temperature is called its solubility.
Reason: Solubility of salts is directly proportional to the temperature.
(A) Both assertion and reason are correct and reason is the correct explanation of assertion.
(B) Both assertion and reason are correct and reason is not the correct explanation of assertion.
(C) Assertion is correct but reason is incorrect.
(D) Both assertion and reason are incorrect.
Ans: (B)
Short Answer Type Questions
12. What is the difference between fog and smoke?
Sol: Fog is a colloidal solution with liquid dispersed in gas. Smoke is a colloidal solution with a solid dispersed in gas.
13. To make a saturated solution, 36 gram of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.
Sol: Mass of sodium chloride (solute) is 36 g.
Mass of water (solvent) is 100 g
Mass of solution = mass of solute + mass of solvent
Mass of solution = 36 + 100 = 136 g
Therefore, concentration percentage
14. The students were asked to prepare a 10% (m/m) sugar solution in water during an experiment. Ramesh dissolved 10 g of sugar in 100 g of water while Sarika prepared it by dissolving 10 g ofsugar in water to make 100 g of the solution.
a. Are the two solutions of the same concentration.
b. Compare the mass % of the two solutions.
Sol:
15. How many grams of water should be added to 15g of salt to obtain 15% of salt solution?
Sol:
16. Classify each of the following as physical or chemical changes. 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) Churning of milk cream to get butter
Sol: a. Physical change because evaporation of water takes place but no change occurs in the composition of the substance.
b. Physical change because it is also involving the only movement of air, no change in the composition of air.
c. Burning of kerosene is a chemical change as new products are formed.
d. Physical change as there is no change in composition. Only the separation of components takes place by the physical phenomenon.
17. How would you confirm that a colourless liquid given to you is pure water?
Sol. Under one atmospheric pressure, the boiling point of water is 100°C and the freezing point is 0°C. When we boil the given colourless liquid, if it boils at 100°C, it is pure water. If not boiling at 100°C temperature, then impurities will be mixed with it hence not pure water.
18. Differentiate between homogeneous and heterogeneous mixtures with examples.
Sol:
19. How are sol, solution, and suspension different from each other?
Sol:
20. 20. A solution contains 60 g of NaCl in 400 g of water. Calculate the concentration in terms of the mass-by-mass percentage of the solution.
Sol. The mass of solute (NaCl) is 60 g
The mass of the solvent (water) is 400 g
Mass of solution= mass of solute + mass of solvent
Mass of solution = 60 + 400 = 460 g
The mass percentage of a solution is a percentage of the ratio of the mass of the solute to the mass of the solution.
21. Differentiate between mixture and compound with examples.
Sol:
| Feature | Mixture | Compound |
|---|---|---|
| Formation | Mixing of elements or compounds | Chemical reaction of elements |
| Composition | Variable | Fixed |
| Properties | Shows constituent properties | New properties |
| Separation methods | Physical methods | Chemical methods |
| Example | Air, blood | NaCl, CO₂ |
22. Distinguish between elements and compounds with one example each.
Sol:
| Feature | Elements | Compounds |
|---|---|---|
| Atoms type | Only one kind of atom | More than one kind of atom |
| Breakdown | Cannot be broken down chemically | Can be broken down chemically |
| Example | Oxygen, Hydrogen | Carbon dioxide, Water |
23. Is water an element or a compound? Give a reason in support of your statement.
Sol. 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.
24. 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?
Sol: Metals are sonorous and highly ductile; hence, this element can be classified as a metal. Other characteristics expected to be possessed by this element are - lustre, malleability, heat and electrical conductivity.
25. (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 this allotropic.
d. Name a non-metal which is known to form the largest number of compounds.
e. Name a non-metal which is required for combustion.
Sol. a. Iodine is a lustrous non-metal.
b. Bromine is a non-metal which exists as a liquid at room temperature.
c. Graphite is the allotropic form of carbon, and it is a good conductor of electricity.
d. Carbon is a non-metal which is known to form the largest number of compounds.
e. Oxygen is a non-metal which is required for combustion.
26. Is air a mixture or a compound? Give three reasons for your answer.
Sol. Air is considered a mixture because of the following reasons:
(i) Air can be separated into its constituents like oxygen, nitrogen, etc., by the physical process of fractional distillation.
(ii) Air shows the properties of all the gases present in it. For example, oxygen supports combustion and air also supports combustion; carbon dioxide turns lime water milky and air also turns lime water milky, though very, very slowly.
(iii) Air has a variable composition because air at different places contains different amounts of various gases.
27. Differentiate between a saturated and an unsaturated solution.
Sol.
Saturated Solution: When a solution cannot dissolve more solute at a given temperature, the point is called the saturation point of the solution and the solution is called saturated solution. This means, no more solute can be dissolved in a saturated solution at a given temperature.
Unsaturated Solution: Solution in which more solution can dissolved at a given temperature, is called unsaturated solution.
Benefits of Practicing CBSE Important Questions Class 9 Science Chapter 2
Practicing CBSE Important Questions for Class 9 Science Chapter 2 Is Matter Around Us Pure? , provide several benefits for students:Deepens Conceptual Understanding: By solving important questions, students reinforce their understanding of key concepts like mixtures, solutions, suspensions, colloids and the methods of separating substances. This ensures a strong foundation in the topic.
Enhances Problem-Solving Skills: Regular practice helps students develop problem-solving skills, enabling them to tackle different types of questions (theoretical, numerical, or application-based) with confidence.
Preparation for Exams: Practicing important questions prepares students for the types of questions they are likely to face in exams. It covers a wide range of possible questions from short-answer to long-answer, improving exam readiness.
Improves Time Management: Working on these questions within a set time frame helps students manage their time efficiently during exams, ensuring they complete the paper within the allotted time.
Clarifies Common Doubts: Many important questions highlight areas where students commonly have doubts. By practicing these questions, students get a chance to clear misconceptions and clarify doubts through repetitive exposure.
Boosts Confidence: Consistent practice builds confidence as students become more familiar with the pattern and format of questions, helping them feel better prepared for their assessments.
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