Students can Download Science Chapter 2 Is Matter Around Us Pure Questions and Answers, Notes Pdf, KSEEB Solutions for Class 9 Science helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.
Karnataka State Syllabus Class 9 Science Chapter 2 Is Matter Around Us Pure
KSEEB Class 9 Science Is Matter Around Us Pure Intext Questions and Answers
Question 1.
What Is Meant by a substance?
Answer :
It is a mixture of more than one kind of pure form of matter.
Question 2.
List the points of differences between homogeneous and heterogeneous mixtures.
Answer :
| Homogeneous Mixture | Heterogeneous Mixture |
| It has a variable composition Eg: Salt in water. |
It has non-uniform compositions |
Question 3.
Differentiate between homogeneous and heterogeneous mixture with examples.
Answer :
| Homogeneous mixture | Heterogeneous mixture |
| 1. No physical detectable boundary. | Physical separation is possible. |
| 2. Particles are a mixture and produce monophasic. | Produces biphasic. |
Question 4.
How are sol, solution, and suspension different from each other?
Answer :
| Sol Solution | Suspension |
| A solution is a homogeneous mixture of two or more substances. | Materials that are insoluble in a solvent and have particles that are visible to naked eyes from a suspension. |
Question 5.
To make a saturated solution of 36 g of sodium chloride in 100 g of water at 293 IC find its concentration at this temperature. evaporates faster than kerosene which
Answer :
Mass of solution is left behind (distillation)
Answer :
Mass of solution
= mass of solute + mass of solvent.
= 36 + 100 = 136 g
Mass % of solution
\(=\frac{\text { Mass of solute }}{\text { Mass of solution }}\) x 100
= \(\frac{36}{136}\) x 100 = 26.47%
Question 6.
how will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than 25°C) which arc miscible with each other?
Answer :
Petrol is highly volatile hence it evaporates faster than kerosene which is left behind (distillation)
Question 7.
Name the technique to separate.
(a) Butter from curd
Answer :
Centrifugation
(b) Salt from seawater
Answer :
Evaporation
(e) Camphor from sali
Answer :
Sublimation
Question 8.
Why type of mixtures are separated by the technique of crystallization?
Answer :
Purify solid with some impurities. Example: Separation of sugar crystals from separated sugar sol Lit on.
Question 9.
Classify the following as chemical or physical changes.
1. Cutting of trees
Answer :
Physical change
2. Melting of butter in a pan
Answer :
Physical change
3. Rusting of almirah
Answer :
Chemical change
4. Boiling of water to form steam
Answer :
Physical change
5. Passing of electric current through water and water breaking down into hydrogen and oxygen gases
Answer :
Chemical change.
6. Dissolving common salt in water
Answer :
Physical change
7. Making fruit salad with raw fruits
Answer :
Physical change
8. Burning of paper and wood
Answer :
Chemical change.
Question 10.
Try segregating the things around you as pure substances or mixtures.
Answer :
Pure substances: Gold, Sugar. Water, Rice
Mixtures: Stainless steel, plastic, air, milk.
KSEEB Class 9 Science Is Matter Around Us Pure Textbook Exercise Questions and Answers
Question 1.
Which separation techniques will you 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) Distillation
(b) Sublimation
(c) Filtration
(d) Chromatography
(e) Centrifugation
(f) Separation
(g) Filtration
(h) Magnetic Separation
(i) Sedimentation
(j) Filtration and Decartation
Question 2.
Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.
Answer :
Boil the cup of water containing sugar till sugar dissolves add tea-spoon of tea- leaves, which is insoluble in water boil the content, filter and separate the 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 the substance dissolved in 100 grams of water to form a saturated solution).
(a) What mass of potassium 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) KNO2 needed for the saturated solution at 313 K, which is about 62 gm
\(\frac{620 \times 50}{100}\) = 31gm
(b) KC1 on cooling to get a saturated solution
(c) Solubility at 293 K
- potassium nitrate = 32 gm
- sodium chloride = 36 gm
- potassium chloride = 35 gm
- ammonium chloride = 37 gm
Ammonium chloride, solubility is more at this temperature (solubility increases with increase in temperature)
(d) Rate of solubility increases with increase in temperature.
Question 4.
Explain the following giving examples.
(a) saturated solution
(b) pure substance
(c) colloid
(d) suspension
Answer :
(a) Saturated solution: The maximum quantity of solute dissolves in a given volume of solvent at a given temperature.
(b) Pure substances: Contains only one type of particle. Example: Pure metals like gold.
(c) Colloid: Homogeneous solutions in which solute particles are bigger than true solution examples. Ink, blood, milk.
(d) Suspension: Heterogeneous mixture in which the solute particles are big enough to settle down. Example: Paints, dosa batter.
Question 5.
Classify each of the following as a homogeneous or heterogeneous mixture. soda water, wood, air, soil, vinegar, filtered tea.
Answer :
Homogeneous: Vinegar, filtered tea, air, soda water Heterogeneous: Wood, soil
Question 6.
How would you confirm that a colorless liquid given to you is pure water?
Answer :
The boiling point is the surest test to check the purity. If the water boils arbitrary 100°C.. then it is pure.
Question 7.
Which of the following materials fall into the category of a “pure substance”?
(a) Ice
(b) Milk
(c) Iron
(d) Hydrochloric acid
(e) Calcium oxide
(f) Mercury
(g) Brick
(h) Wood
(i) Air.
Answer :
Pure substances: Iron, ice, hydrochloric, acid, calcium oxide, and mercury.
Question 8.
Identify the solutions among the following mixtures.
(a) Soil
(b) Seawater
(c) Air
(d) Coal
(e) Soda water.
Answer :
Solutions: Water, air, seawater, soda water
Question 9.
Which of the following will show the “Tyndall effect”?
(a) Salt solution
(b) Milk
(c) Copper sulfate solution
(d) Starch solution.
Answer :
Milk and starch silicon
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
Answer :
(a) Elements: Sodium, silver, tin, silicon
(b) Compounds: Calcium carbonate, methane, carbon dioxide, soap
(c) Mixtures: Sugar solution, soil, coal, air, 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:
(a) Growth of a plant,
(b) Rusting of iron
(c) Cooking of food
(d) Digestion of food,
(e) Burning of a candle.
KSEEB Class 9 Science Is Matter Around Us Pure Additional Questions and Answers
Question 1.
What is the special name of Alloy?
Answer :
Solid solution
Question 2.
Mention the properties of Metals.
Answer :
- they have lustrous
- conduct heat and electricity
- they are ductile
- they are malleable
- they are sonorous
Question 3.
Name the liquid metal.
Answer :
Mercury
Question 4.
What are metalloids? Give examples.
Answer :
Elements that have the properties of both metals and nm metals. Ex: boron, silicon, and germanium
Question 5.
What is a compound?
Answer :
A substance composed of two or more elements. Chemically combined with one another in a fixed proportion.
Question 6.
Mention the differences between mixtures and compounds.
Answer :