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Kerala State Syllabus 8th Standard Basic Science Solutions Chapter 15 Solutions
Solutions Textbook Questions and Answers
Kerala Syllabus 8th Standard Chemistry Notes Question 1.
Given below are some solutions. Identify and write down the solvent and the solute present in them. (Hint: Those present in large amount is the solvent and that in small amount is the solute).
Answer:
| Solution | Solvent | Solute |
| Saltwater | Water | Salt |
| Ornamental gold | Gold | Copper |
| Soda water | Water | CO2 |
| Dilute hydrochloric acid | Water | Hydrochloric acid |
Basic Science For Class 8 Chapter 15 Kerala Syllabus Question 2.
Haven’t you noticed the caption “Shake well before use” in certain medicine bottles?
a. To which class do the substances in them belong to? (Colloid, Solution, Suspension)
b. What is the relevance of such instructions on these bottles?
Answer:
a. Suspension
b. It is used after shaking well because it is settled down after a long time.
8th Class Biology Notes Pdf Malayalam Medium Question 3.
Given below are some activities and observations done by a student using samples of dilute rice water, saltwater, and muddy water.
a. Complete the table with the missing observations, 3
b. Classify these samples into solution, colloid, and suspension.
Answer:
8th Class Biology Notes Pdf Kerala Syllabus Question 4.
There are numerous instances in daily life where solutions are being used. Tabulate some of them.
Answer:
- To make artificial soft drinks
- To make coffee, tea, and juices
- For painting
- Plastering with cement
8th Standard Chemistry Notes Pdf Kerala Syllabus Question 5.
You are now familiar with different types of solutions.
a. What is the difference between saturated and supersaturated solutions?
b. How will you prepare a supersaturated solution of common salt?
c. Unsaturated and supersaturated solutions of copper sulfate are prepared in separate beakers and a crystal of copper sulfate is dipped into each one of them. What would be the observation after a day? Give reasons.
Answer:
a. Saturated solution – The solution in which maximum amount of solute is dissolved A solution which contains more amount of solute than that is required to saturate it is known as Supersaturated solution.
b. Prepare a saturated solution dissolving salt in water. Then the solution is heated and dissolves more solute in it.
c. The size of crystal in the Supersaturated solution increases. This is because of the excess solute stacked on the crystal.
8th Class Chemistry State Syllabus Question 6.
Classify and tabulate the mixtures given below into solution, colloid, and suspension:
Milk, fog, atmospheric air dilute acid, lime water, ink, smoke.
Answer:
Solution:- Dilute acid, atmospheric air
Colloid:- Milk, Smoke, Fog,
Suspension:- Lime water
Solutions Additional Questions & Answers
Hsslive Guru Chemistry 8 Kerala Syllabus Question 1.
Tabulate the components of solution given below.
(saltwater, soda water, ornamental gold, air)
Answer:
| Solution | Components |
| Saltwater | Salt, Water |
| Soda water | C02 Water |
| Ornamental gold | Gold, Copper |
| air | Nitrogen, Hydrogen, CO2, Oxygen, etc |
8th Standard Physics Notes Pdf Kerala Syllabus Question 2.
Complete the table.
Answer:
a. Solid
b. Gas
c. Liquid
d. Liquid
e. Liquid
f. Solid
g. Liquid
h. Liquid
Basic Science Class 8 Chapter 15 Kerala Syllabus Question 3.
A child took 3 glasses of equal quantity of water and put half teaspoon salt in one glass and two teaspoon salts in the other. Which is the concentrated solution? Justify your answer.
Answer:
The concentrated solution is in the second glass because the amount of solute is greater in quantity in a concentrated solution
Kerala Syllabus 8th Standard Physics Notes Question 4.
What are the factors affecting the solubility?
Answer:
The nature of solute and the temperature
Kerala Syllabus 8th Standard Chemistry Notes Malayalam Medium Question 5.
Classify the following mixtures as Homogeneous and Heterogeneous
Sugar solution, muddy water, mixture of water and kerosene, salt solution, air, smoke
Answer:
| Homogeneous | Heterogeneous |
| Sugar solution | Mixture of water anc kerosene |
| Salt solution Air | Muddy water Smoke |
8th Class Biology Notes Pdf Kerala Syllabus Question 6.
Tabulate the two differences of solution and colloid.
Answer:
| Solution | Colloid |
| The size of particle solute is very less | The size of particle is of comparatively larger |
| Cannot scatter the light, therefore, it is not visible | Scatter the light and therefore path of light is visible |
Basic Science Class 8 Ch 15 Kerala Syllabus Question 7.
Tabulate the differences between solution and suspension.
Answer:
| Solution | Suspension |
| Size of the particle very small | Can be seen by naked eye |
| Cannot scatter the beam of light | Scatter the beam of light |
| Cannot separate by filtration | Can be separated by filtration |
| Particles are not settled down when keep if undisturbed | Particles are settled down |
Kerala Syllabus 8th Standard Biology Notes Malayalam Medium Question 8.
Why does the path of light seen when dust particles are spread in cinema theatre and smart room.
Answer:
When dust particles are spread in air the air becomes suspension. Then it can scatter the light and so the path can be seen
Scert Class 8 Science Notes Kerala Syllabus Question 9.
What is meant by stabilizer; give example.
Answer:
The soft drinks available in market do not settle down even after prolonged storage. To retain as such for long time without settling down some chemicals are added to it. These are called stabilizers.
Eg. Brominates vegetable oil.
Basic Science Class 8 Solutions Kerala Syllabus Question 10.
Explain what are saturated and supersaturated solution?
Answer:
The solution obtained by dissolving maximum amount of solute at a given temperature is known as saturated solution. A solution which contains more amount of solute than that is required to saturate it is known as supersaturated solution.
8th Standard Chemistry Textbook Kerala Syllabus Question 11.
How can we prepare the supersaturated solution of salt?
Answer:
Prepare a saturated solution dissolving salt in water. Then the solution is heated and dissolves more solute in it
Class 8 Basic Science Chapter 15 Kerala Syllabus Question 12.
What are crystals; How can we make growing crystals?
Answer:
Prepare a saturated solution of a sol-ute like copper sulfate. When we allow it to evaporated slowly, the crystals are appeared. Select a suitable crystal and hang it in the solution with a twain. After a few days, the crystal can be seen grown as well.
Question 13.
Collect the names of the preservative commonly used and write its the side effects.
Answer:
Common salt, sugar, acetic acid, sodium meta bisulfate. Overuse of salt causes hypertension (blood pressure). Use of sugar effects badly on diabetic patients. Acetic acid causes acidity.
Question 14.
What is “Tyndall effect”
Answer:
The colloidal particles can scatter light and so we can see them. This is Tyndall effect.