SEBA Class 9 Science Important Chapter 2 Is Matter Around Us Pure?

SEBA Class 9 Science Important Chapter 2 Is Matter Around Us Pure? Solutions English Medium As Per SEBA New Syllabus to each chapter is provided in the list so that you can easily browse through different chapters SEBA Class 9 General Science Additional Solutions and select need one. NCERT Important Solutions For Class 9 General Science Download PDF. Important Notes for Class 9 Science.

SEBA Class 9 Science Important Chapter 2 Is Matter Around Us Pure?

Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. Assam SEBA Board Class 9 Science Additional Question Answer are part of All Subject Solutions. Here we have given CBSE Class 9 Science Important Notes for All Chapters, You can practice these here.

Is Matter Around Us Pure?

Chapter: 2

IMPORTANT QUESTION ANSWER

Answer the Following Question:

1. What is meant by a pure substance?

Ans: A pure substance consists of only one type of particle and has a uniform composition and properties throughout. Examples include elements (like oxygen) and compounds (like water).

2. What is a solution? Give two examples.

Ans: A solution is a homogeneous mixture where one substance (solute) dissolves in another substance (solvent).

Examples: (i) Sugar in water.

(ii) Salt in water.

3. What is the Tyndall effect?

Ans: The Tyndall effect is the scattering of light by the particles in a colloidal mixture. This makes the path of light visible.

Example: Light passing through fog or milk.

4. What is the effect of temperature on the solubility of a salt?

Ans: Increasing temperature generally increases the solubility of solids in liquids. However, the effect may vary for different substances. For example, potassium nitrate has much higher solubility at higher temperatures.

5. What are colloids? Give two examples.

Ans: Colloids are mixtures in which the solute particles are dispersed throughout the solvent but are not visible to the naked eye. They show the Tyndall effect.

Examples: (i) Milk. 

(ii) Fog.

6. Define the term ‘concentration’ of a solution.

Ans: The concentration of a solution refers to the amount of solute dissolved in a given amount of solvent. It can be expressed in mass by mass percentage, mass by volume percentage, or volume by volume percentage.

7. How can you confirm that a liquid is pure water?

Ans: To confirm that a liquid is pure water, you can check its boiling point (100°C at 1 atmosphere pressure) and freezing point (0°C). Additionally, pure water does not conduct electricity because it lacks ions.

8. Why do we see particles in a colloidal solution scatter light?

Ans: In a colloidal solution, the particles are large enough to scatter the light passing through, making the light’s path visible. This phenomenon is known as the Tyndall effect.

9. Explain the process of filtration with an example.

Ans: Filtration is a process used to separate solid particles from liquids or gases using a filter. The mixture is poured through a porous material that allows only the liquid or gas to pass.

Example: Separating sand from water using a filter paper.

10. How does temperature affect the solubility of a substance?

Ans: Increasing the temperature generally increases the solubility of solid solutes in liquids because the particles move faster, allowing them to dissolve more easily. For gases, the solubility decreases as the temperature rises.

11. What is the importance of the concentration of a solution?

Ans: The concentration of a solution indicates the amount of solute present in a given amount of solvent. It helps determine the strength of the solution, whether it is dilute, concentrated, or saturated. The concentration affects the properties and reactivity of the solution.

12. What is a suspension? How can you separate the components of a suspension?

Ans: A suspension is a heterogeneous mixture where the solute particles are large and visible. These particles settle over time.

To separate a suspension, you can use filtration, where the solid particles are trapped by filter paper, and the liquid passes through.

13. Explain how you can separate a mixture of oil and water.

Ans: You can separate oil and water by using a separating funnel. Since oil is less dense than water, it will form the upper layer, and water will form the lower layer. By opening the valve of the separating funnel, you can collect the two liquids separately.

14. What is the significance of solubility in preparing solutions?

Ans: Solubility determines how much solute can be dissolved in a solvent at a given temperature. It is crucial for preparing solutions of desired concentration, especially in pharmaceuticals, chemical reactions, and daily life (e.g., preparing a sugar syrup).

15. What happens when a solution is cooled slowly?

Ans: When a saturated solution is cooled slowly, the solute particles may crystallize and come out of the solution. This is because the solubility decreases with a drop in temperature, and the solution becomes supersaturated.