ACTIVITIES ADDITIONAL QUESTIONS AND SELF ACTIVITIES
CONTENTS SOLUTION CONCENTRATION OF SOLUTION SATURATED AND UNSATURATED SOLUTION SUPER SATURATED SOLUTION
CHAPTER 15
Leela and Gopi were making lemonade for their friends . Leela cut the lemons and Gopi made the sugar dissolve in water. Then they both mixed them both in a big jar. Have you ever tried to make lemonade? If so can you tell me how it is made in your home?
WHAT IS SOLUTION? You have already noticed that Gopi mixed sugar and water to make sugar solution. Do you know any other solutions? List them below Salt solution
A solution can be made when two substances of different quantities are mixed. The amount of substance dissolved in smaller quantities are called solute and that in larger quantities are called solvent. The solute and solvent mixed together to get solution. Therefore, in sugar solution sugar is the solute, and water is the solvent.
ACTIVITY Complete the table given below. SOLUTION
SOLUTE
SOLVENT
Salt solution
salt
water
CuSO4 solution
water
Soda water
Carbon dioxide
CONCENTRATION OF THE SOLUTION While drinking the lemonade Leela’s friend said that she needs more sweetness to the lemonade. So Leela added a little more sugar to the lemonade to make it sweeter. Why do you think the sweetness increased? Let’s do an experiment! ACTIVITY Take four beakers, beaker A, B, C and D . Fill each of them with water. Then add 1 ACTIVITY teaspoon of CuSO powder in beaker A and and 2 teaspoon of CuSO powder in 4
4
beaker B , 3 teaspoon in beaker C and 4 teaspoon in beaker D. Stir it well. What do you observe?
What do you observe? In which beaker is the colour intense? Why do you think so? A
B
C
D
The concentration of a solution is the amount of solute dissolved in a fixed amount of solution. A solution with relatively higher amount of solute is called concentrated solution and a solution that have lower amount of solute is the dilute solution.
SATURATED AND UNSATURATED SOLUTION While making the sugar solution Gopi accidentally put more sugar in water and tried to make it dissolve by stirring it. He failed to dissolve the whole sugar that he added resulting in the lump of sugar in the bottom of the jar. Leela tried to taste it. “Oh! It’s too sweeet. What do we do now?”
Hearing this Leela’s mother came to the rescue. She added more water to the solution and stirred it well. the sugar completetely dissolved. What do you think may be the reason behind this? ACTIVITY Take a beaker. Add 100 ml of water in it. Then add one spoonful of salt in it and stirr it well. Repeat this process until no salt can be further dissolve in it.
What do you observe? What happens when more salt is added to it?
The solution obtained by dissolving maximum amount of solute is k
saturated solution.The solution before reaching saturation is known unsaturated solution.
SUPERSATURATED SOLUTION Gopi and Leela wondered whether they can make the excess sugar dissolve in water without adding more water to it. Then mother took some of the concentrated sugar solution and heated it . “ Wow! The sugar has completely dissolved in it” Gopi wondered. What may be the reason behind this? The solution which contains more solute than a saturated solution is known as supersaturated solution. It can be made by heating the saturated solution, stirring and adding more solute to it.
ACTIVITY Find out some examples where supersaturated solution is used from your home surroundings and list them below. Gulab jamun
Chocolate milk Additional Information
yum yum yummyyy!!!! Let’s make some sugar candy. Make a supersaturated solution of sugar solution and stir it well.Take a stick and tie a thread in the middle . At the end of the thread tie a sugarcandy crystal in it.Then dipp it in the hot super saturated solution and allow it to cool . See the magic !!!!!
check the link for video explanation. https://youtu.be/WQdXbf8huuQ
SUMMARY A solution is made by adding solute to the solvent. Amount of substance dissolved in smaller quantity is solute and that of larger is solvent Concentration of a solution is the amount of solute dissolved in fixed amount of solution. The solution obtained by dissolving maximum amount of solute is known as saturated solution. The solution before reaching saturation is known as unsaturated solution. The solution which contains more solute than a saturated solution is
ADDITIONAL QUESTIONS 1. The amount of solute dissolved in fixed amunt of solvent is known as [ Solution,
Concentration,
Solvation ]
2. In a solution of dilute hydrochloric acid, which one is solute and what is the solvent? 3. Suggest some examples for solutions which are not liquids. 4. Complete the following table Solution Salt Solution
Solvent Water
Solute ________________
Dilute Hydrochloric Acid ____________
HCl
Soda Watter
Water
_______________
Copper sulphate solution
______________
CuSO4 powder
5. A student was asked to prepare saturated salt solution but accidentally heated the solution, which results in dissolving more salt. What may be the reason behind it ? 6. What happens to the supersaturated solution when the solution is allowed
to cool down?
Lets think Imagine that you are a participant in a sciencefair and you were asked to conduct an experiment on concentration of the solution indicating saturated and unsaturated solution. Prepare a rough procedure of the experiment you
LEARNING OUTCOMES Learners can remember the concept of solution Learners can differentiate between saturated and unsaturated solution. Learners can explain why unsaturated solution on cooling gets precipitate the solutes.
Learners create new experiments for the proper explanation of the concept of super saturation