NCERT Solutions for Class 9 Science Chapter 2 Is Matter Around Us Pure: Through the chapter Is Matter Around Us Pure, you will be able to understand that pure substances can be elements or compounds. An element is a form of matter that can't be weakened by chemical reactions into simpler substances and compound is a substance composed of two or more different types of elements. They are chemically combined in a fixed proportion and the properties of a compound are different from its constituent elements, whereas a mixture shows the properties of its constituting elements or compounds. The solutions for NCERT Class 9 Science chapter 2 Is Matter Around us Pure covers all the questions mentioned at the end of the chapter and additional questions mentioned in between the chapter.
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In NCERT Class 9 Science chapter Is matter around us pure, you will get to know about types of mixtures, how to separate the components of a mixture, types of pure substances and physical and chemical changes. The NCERT solutions are here to help you to understand all the important topics mentioned in the NCERT syllabus through questions . If you have any problem in answering the questions or you are not getting the correct answers then don't worry, CBSE NCERT solutions for Class 9 Science chapter 2 Is Matter Around Us Pure is there for you to help.
NCERT solutions for class 9 science chapter 2 Is Matter around us pure?: Solved In-text Questions
Topic 2.1 What is a mixture?
Q 1. What is meant by a substance?
A substance is a matter which consists of a single type of particles and has specific properties. For example tin, sulfur, pure sugar (sucrose) etc.
Q 2. List the points of differences between homogeneous and heterogeneous mixtures.
The differences between homogeneous and heterogeneous mixtures-
| HOMOGENEOUS || HETEROGENOUS |
| 1. It has uniform compositions. |
2. No visible boundaries of separation.
3. It consists of only one phase.
examples- sugar + water = sugar solution
| 1. It does not have a uniform composition |
2. Visible boundaries of separation
3. They consist of more than one phase.
examples- sugar +sand = sugar + sand
NCERT free solutions for class 9 science chapter 2 Is Matter around us pure?
Topic 2.2 What is a solution?
Q 1. Differentiate between homogeneous and heterogeneous mixtures with examples.
Homogeneous Mixture: It is a mixture in which different constituents are mixed uniformly and these constituents cannot be easily separated.
Example: Sugar solution, soda, water, soft drinks, vinegar, air, etc.
Heterogeneous mixtures: It is a mixture in which different constituents are not mixed uniformly and the constituents can be easily seen and can be easily separated.
Example: Sugar and sand mixture, milk, ink, paint, wood, blood, etc.
Q 2. How are sol, solution and suspension different from each other?
Difference between sol, solution and suspension are given below:
| Sol(Colloids) || Suspension || Solution |
| 1. Heterogeneous mixture || 1. Heterogeneous mixture || 1.Homogeneous mixture |
| 2. We cannot see the size of the particle with a naked eye. || 2. Particles are visible by the human naked eye || 2. the particles are not visible to a naked eye. |
| 3. They can scatter the beam of light passing through them || 3. scatters the beam of light passing through them || 3. unable to scatter the beam of light. |
| 4. Solute particles cannot be separated by filtration and sedimentation. || 4. Solute particles can be separated by filtration || 4. solute particles cannot be separated by filtration and sedimentation. |
Q 2. Name the technique to separate
(i) butter from curd,
(ii) salt from sea-water
(iii) camphor from salt.
The following techniques are used to separates them-
(i) Centrifugation method
(ii) Evaporation and
NCERT textbook solutions for class 9 science chapter 2 Is Matter around us pure?
Topic 2.4 Physical and Chemical changes
Q 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 the water breaking down into hydrogen and oxygen gases,
• dissolving common salt in water,
• making a fruit salad with raw fruits, and
• burning of paper and wood
- 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
- rusting of almirah,
- passing of electric current, through water and the water breaking down into hydrogen and oxygen gases,
- burning of paper and wood
NCERT solutions for class 9 science chapter 2 Is Matter around us pure?: Solved Exercise Questions
Q 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.
The following separation techniques are used to separate-
a) Sodium chloride from its solution in water. by Evaporation, method
b) Ammonium chloride from a mixture containing sodium chloride and ammonium chloride. by Sublimation
c) Small pieces of metal in the engine oil of a car. by filtration.
d) Different pigments from an extract of flower petals. by chromatography,
e) Butter from curd. by centrifugation,
f) Oil from water. by separation funnel
g) Tea leaves from tea. by filtration,
h) Iron pins from sand. by magnetic separation,
i) Wheat grains from husk. by winnowing or sedimentation,
j) Fine mud particles suspended in water. by decantation and filtration .
Q 4.(a) Explain the following giving examples.
Saturated solution - In a given solvent, when no more solute can be dissolved in a solution at a given temperature is called a saturated solution.
Q 4.(b) Explain the following giving examples
Pure substance -
A pure substance is a matter which consists of a single type of particles and has specific properties. For examples tin, sulphur, pure sugar (sucrose) etc.
Q 4.(c) Explain the following giving examples.
A colloid is a solution in which the solute particle is bigger in size as compare to the true solution. It is a heterogeneous mixture. Because of the small size of colloidal particles, we cannot see them with naked eyes. For example milk and blood.
Q 4.(d) Explain the following giving examples.
It is a heterogeneous solution in which the solute particles do not dissolve in solvent but remain suspended throughout the bulk of the medium. Particles are visible by naked eyes. Chalk-water is an example of this type of solution.
Q 5. Classify each of the following as a homogeneous or heterogeneous mixture.
soda water, wood, air, soil, vinegar, filtered tea.
The mixture of following are homogeneous in nature-
Soda water, vinegar, and filtered tea. as there are no separation boundaries in their solution.
Heterogeneous - Wood, air and soil. As we can easily see the separation boundaries.
Q 7. Which of the following materials fall in the category of a “pure substance”?
(d) Hydrochloric acid
(e) Calcium oxide
A pure substance is a matter which consists of a single type of particles and has specific properties-
Therefore, the following given substances are '' pure substance " -
- Hydrochloric acid
- calcium oxide and
Q 8. Identify the solutions among the following mixtures.
(e) Soda water
A solution is a homogeneous mixture of two or more than two substances.
So, according to the definition, out of the given seawater, air and soda water are examples of solutions.
Q 9. Which of the following will show the “Tyndall effect”?
(a) Salt solution
(c) Copper sulphate solution
(d) Starch solution.
Tyndall effect is shown by the colloidal solution and suspension and it is not shown by a true solution.
Therefore, in the above-given solution only milk and starch solution will be able to scatter the light and hence show Tyndall effect.
Q 10. Classify the following into elements, compounds, and mixtures.
(c) Sugar solution
(e) Calcium carbonate
(l) Carbon dioxide
Elements cannot be broken down into any simpler substance. and the compounds have fixed composition can be broken down into elements by chemical or electrochemical reaction. Mixtures have no fixed composition they are either homogeneous or heterogeneous.
Therefore, Sodium, Silver, Tin, and Silicon are elements.
Q 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.
Out of given following are the examples of chemical changes-
- Growth of plants
- Rusting of iron
- cooking of food
- Digestion of food
- Burning of candle
Is Matter Around Us Pure Class 9 Science Chapter 2 Topics :
2.1 What Is a Mixture?
2.1.1 Types of Mixtures
2.2 What Is a Solution?
2.2.1 Concentration of a Solution
2.2.2 What Is a Suspension?
2.2.3 What Is a Colloidal Solution?
2.3 Separating the Components of a Mixture
2.3.1 How Can We Obtain Coloured Component (dye) from Blue/ Black Ink?
2.3.2 How Can We Separate Cream From Milk?
2.3.3 How Can We Separate a Mixture of Two Immiscible Liquids?
2.3.4 How Can We Separate a Mixture of Salt and Camphor?
2.3.5 Is the Dye in Black Ink a Single Colour?
2.3.6 How Can We Separate a Mixture of Two Miscible Liquids?
2.3.7 How Can We Obtain Different Gases from Air?
2.3.8 How Can We Obtain Pure Copper Sulphate from an Impure Sample?
2.4 Physical and Chemical Changes
2.5 What Are the Types of Pure Substances?
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