ICSE Class 6 Chemistry Important Questions Chapter 7 Water

Chemistry ICSE Class 6 Important Questions Chapter 7 Water

Practice Questions

Question 1.
What should be the characteristics of potable water ?
Answer:

1. It should be odourless and colourless.
2. It should contain dissolved gases like oxygen and carbon dioxide.
3. It should contain dissolved minerals and salts which give it a pleasant taste.
4. It should not contain any suspended impurity, germs or harmful salts like urea, nitrate, etc.

Question 2.
What is Chlorination ?
Answer:
The addition of chlorine to water is called chlorination. It is a method to purify water by killing germs in it.

Question 3.
Name few water-borne diseases.
Answer:
Cholera, diarrhea, typhoid, gastroenteritis, dysentery, jaundice, etc.

Question 4.
Name one water-born disease caused by –
1. bacteria
2. virus.
Answer:
1. Dysentery
2. Hepatitis

Question 5.
Mention the conditions affecting the formation of solutions.
Answer:

1. Nature of the solute and the solvent.
2. Stirring or shaking.
3. Heating
4. Size of the solute particles.

Question 6.
Why is distilled water not good for drinking ? Mention two uses of distilled water.
Answer:
Distilled water is not good for drinking because –
1. It taste flat and
2. it lacks dissolved salts and minerals that are required for our body.

Uses of destilled water :
1. It is used for preparing solutions for medicinal purposes and in laboratories.
2. It is also used in car and inverter batteries.

Question 7.
Define water pollution.
Answer:
Any undesirable change in the physical, chemical and biological conditions of water which make it unfit for plants, animals and human beings is called water pollution.

Question 8.
Write various ways to conserve water.
Answer:

1. Forest area should be increased as they help in causing rainfall.
2. Industrial and domestic waste water should be recycled and reused to the maximum extent possible.
3. Drip irrigation or spray irrigation system should be encouraged.
4. Rainwater harvesting should be done at domestic and community levels.
5. Avoid wasting water at home by not leaving the tap running while brushing your teeth and getting defective taps fixed.

Question 9.
Fill in the blanks.
1. About ………….. percent of the earth’s surface is covered with water.
Answer:
About 70 percent of the earth’s surface is covered with water.

2. Only …………. percent of the earth’s water is fresh water.
Answer:
Only 3 percent of the earth’s water is fresh water.

3. Groundwater comes out of the surface at some places naturally to form ………….
Answer:
Groundwater comes out of the surface at some places naturally to form natural springs.

4. …………. is the only substance which exists in all three states of matter.
Answer:
Water is the only substance which exists in all three states of matter.

5. Almost …………… percent of our body is made up of water.
Answer:
Almost 70 percent of our body is made up of water.

6. ………….. helps in regulating our body temperature.
Answer:
Water helps in regulating our body temperature.

7. A special membrane made of …………. is used in the process of reverse osmosis.
Answer:
A special membrane made of cellulose acetate is used in the process of reverse osmosis.

8. A substance that dissolves in a liquid is said to be ………….. in it and which does not dissolve in a liquid is said to be ………… in it.
Answer:
A substance that dissolves in a liquid is said to be soluble in it and which does not dissolve in a liquid is said to be insoluble in it.

9. The finer (smaller) the size of the solute, the …………. is the rate of formation of solution.
Answer:
The finer (smaller) the size of the solute, the faster is the rate of formation of solution.

10. The solubility of common salt is ………….. g per 100 g of water at 20°C.
Answer:
The solubility of common salt is 36 g per 100 g of water at 20°C.

11. The substances that pollute water are called …………
Answer:
The substances that pollute water are called water pollutants

12. Discharge of hot water from industrial and thermal plants enter water body and change its temperature causing …………… pollution.
Answer:
Discharge of hot water from industrial and thermal plants enter water body and change its temperature causing thermal
pollution.

13. ………….. is the excessive growth of algae and other water plants in water leading to depletion of oxygen level in water and death of aquatic life.
Answer:
Eutrophication is the excessive growth of algae and other water plants in water leading to depletion of oxygen level in water and death of aquatic life.

ICSE Class 6 Chemistry Important Questions