10 - Solubility 

In this post, you can check the solutions to the exercises of Solubility of Oasis School Science Grade 9 by Jayananda Kapadi.

Group A

1. What is a mixture? Give one example.
Answer: A mixture is a impure substance which is the combination of two or more than two substance in any proportion by weight. One example is the combination of sand and salt.

2. Define homogeneous mixture with one example.
Answer: Homogeneous mixture is defined as a mixture in which the constituent particles are dissolved completely in the mixture and cannot be seen with our naked eyes. One example is the mixture of milk and sugar.

3. What is heterogeneous mixture? Give one example.
Answer: Heterogeneous mixture is defined as a mixture in which the constituent particles are or partially or not dissolved and can be seen with our naked eyes. One example is the mixture of sand and salt.

4. Separate homogeneous mixture and heterogeneous mixture from the given mixture.
  1. Sugar solution - Homogeneous mixture
  2. Sand and sugar - Heterogeneous mixture
  3. Alcohol and water - Homogeneous mixture
  4. Turbid water - Heterogeneous mixture
5. Define solute and solvent.
Answer: Solute is defined as the solid substance that gets dissolved in a solvent. Similarly, solvent is defined as the liquid or fluid that dissolved the solute in it.

6. What is solubility? Write down the formula to calculate the solubility of a substance.
Answer: Solubility is defined as the amount of solute required to form a saturated solution in 100 grams of a solvent in a given temperature.
The formula to calculate the solubility of a substance is:
$Solubility = \dfrac{wt. \ of \ solute \ in \gm}{wt. \ of\ solvent \ in \gm} * 100$

7. What is a solution? Give one example.
Answer: Solution is the mixture of a solute and solvent in which the mixing particles are smaller than or equal to $10^{-7}$ cm in diameter.

8. Define unsaturated solution and saturated solution.
Answer: Unsaturated solution is a type of solution that can dissolve more amount of solute at that temperature without the application of heat.
Saturated solution is a type of solution that can no longer dissolved more amount of solute at that temperature without the application of heat.


9. What are suspension and colloid? Give any two examples of each.
Answer: Suspension is a heterogeneous mixture consisting particles of diameter between $10^{-5}$cm or larger. Example: Sand in water, mud in water.
Colloid is a mixture consisting small particles of diameter $10^{-7}$ cm to $10^{-5} cm. Example: Milk, Blood.

10. What is a solubility curve? Write.
Answer: A graph obtained by plotting the solubility of a substance in the Y-axis and the corresponding temperature (in degree C) in the X-axis is called as a solubility curve. 

11. What is a crystal? Write one method of making big crystals.
Answer: A crystal is a solid substance having a fixed geometrical shape and edges. One method of making big crystals is crystallization.

12. Define dilute solution and concentrated solution.
Answer: Dilute solution is defined as the solution containing relatively less amount of solute. In contrary to it, a solution containing relatively more amount of solute in it is defined as a concentrated solution.

13. If some more solute can be dissolved in a solution at 25$^o$C, write down the type of solution.
Answer: Since more amount of solute can be dissolved in the solution at a fixed temperature i.e. 25$^o$C, the solution is a unsaturated solution.

14. If concentration of solution reduces and crystals appear when solute is added to solution at 40$^o$C, name the type of solution.
Answer: Since concentration of solution reduces and crystals appear in the solution at a constant temperature on adding more amount of solute, the given solution is a saturated solution.

15. What happens when the saturated solution of copper sulphate is heated?
Answer: When the saturated solution of copper sulphate is heated, it can dissolve more amount of solute in it as it turns into a super saturated solution.

16. What happens when supersaturated solution of sodium chloride is cooled?
Answer: When supersaturated solution of sodium chloride is cooled, excess solute which was dissolved in the solution on raising the temperature cools down and sediments at the bottom of the beaker in the form of crystals.


17. What type of substance is called a crystalline substance?
Answer: A solid substance having a fixed geometrical shape is called a crystalline substance.

18. What type of substance is called an amorphous substance?
Answer: A substance that does not have a fixed geometrical shape is called an amorphous substance.

19. What is the size of particles dissolved in a solution?
Answer: Particles dissolved in a solution are of diameter $10^{-7}$ cm or smaller. 

About this book:

Oasis School Science Grade 10
Author: Jayananda Kapadi
Editor: Dr. Rameshwar Adhikari

About Oasis Publication:

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