ICSE Class 7 Chemistry Important Questions Chapter 4 Chemistry in Everyday Life

Chemistry ICSE Class 7 Important Questions Chapter 4 Chemistry in Everyday Life

Question 1.
Write few uses of silver.
Answer:

1. It is used for making coins, jewellery and silverware.
2. It is used in the preparation of some medicines such as eye drops and in dental hygiene. It is also used for filling tooth cavities.
3. It is used for electroplating metal articles to resist corrosion.

Question 2.
Write two uses of iodine.
Answer:

1. Tincture of iodine is widely used as a disinfectant and antiseptic.
2. It is used to prepare silver iodide which is used for making photographic films.

Question 3.
What is vulcanization ?
Answer:
The process of adding sulphur to rubber is called vulcanization. It makes the rubber more durable.

Question 4.
How are alloys different from its constituent metals from which it is made ?
Answer:
It general, alloys –

1. are stronger than the metals from which they are made.
2. are more resistant to corrosion.
3. have a lower melting point than the constituent metals.
4. have lower electrical conductivity than pure metals.

Question 5.
What are inorganic and organic compounds ?
Answer:
Inorganic compounds are those which are obtained from minerals. For example, common salt, hydrochloric acid, sulphuric acid, etc. Organic compounds are those which are obtained from living organisms such as plants and animals. All organic compound are carbon-based compounds. For example, carbohydrates, fats, proteins.

Question 6.
What is rock salt ?
Answer:
The large crystals of common salt found in the underground deposits are called rock salt, which are usually brown due to the presence of impurities in it.

Question 7.
Write two uses of zinc oxide.
Answer:
1. It is used as a white pigment in paints.
2. It is used as a component in oinments to treat skin diseases.

Question 8.
Name few silicon compounds and mention their uses.
Answer:

1. Sand (silicon dioxide, SiO₂) – It is used in the manufacture of glass and cement.
2. Sodium silicate (water glass, Na₂SiO₃) -It is used as an adhesive for joining pieces of china clay. Dissolved water glass is used as preservative for eggs and also used in the soap industry.
3. Silicon carbide (SiC) – It is used to make cutting tools and as abrasive in grinding wheels and grinding stones.

Question 9.
What are different types of fertilizers ?
Answer:
According to the elements fertilizers supply to the soil, they are classified as :

1. Nitrogenous fertilizers : Examples : urea (NH₂CONH₂), ammonium nitrate (NH₄NO₃), ammonium sulphate [(NH₄),SO₄]
   Potassium fertilizers – Examples : Potassium nitrate (KNO₃), potassium sulphate (K₂SO₄), potassium chloride (KCl).
   Phosphatic fertilizers – Examples, Calcium superphosphate, Diammonium phosphate, triammonium phosphate.
   NPK fertilizers

Question 10.
What is blue vitriol ?
Answer:
Blue vitriol is hydrated copper sulphate [CuS04 5H20]. It is used chiefly as a pesticide and germicide in agriculture. It is also used in electroplating of copper and as an electrolyte for batteries.

Question 11.
Give two examples of
1. pesticides
2. fungicides.
Answer:
1. Pesticides – DDT (dichlorodiphenyl-trichloroethane), BHC (benzene hexachloride) and malathion
2. Fungicides – Sulphur sprays, bordeaux mixture.

Question 12.
State two uses of hydrocarbons.
Answer:
1. Used as fuel, e.g., methane, LPG
2. Serves as raw material for the manufacture of plastics, rubber, fibres, etc.

Question 13.
Write full form of
1. CNG
2. LPG
Answer:
1. CNG – Compressed natural gas
2. LPG – Liquefied petroleum gas

Question 14.
What are the raw materials needed for the manufacture of cement ?
Answer:

1. Limestone – which provides lime
2. Clay – which provides alumina and silica.
3. Gypsum – CaSO₄.2H₂O

Question 15.
Write ingredient used for manufacturing –

1. glass
2. soap
3. mortar
4. concrete

Answer:

1. Glass – limestone, soda ash and sand
2. Soap – Sodium hydroxide, vegetable oils or fats, sodium chloride
3. mortar – cement, sand and water
4. concrete – cement, sand, gravel or marble chips.

Question 16.
Name the plastic that you would use for.

1. making frying pans
2. making raincoats
3. making pipes
4. making thermocol
5. making guttons, switches

Answer:

1. PTFE or TEFLON
2. Polyvinyl chloride (PVC)
3. Polythene
4. Polystyrene
5. Bakelite

Question 17.
What are silicones ?
Answer:
Silicones are chemical substances that consist of silicon and oxygen atoms. They are waterproof and used for making waterproof cloth, waxes and polishes. They are also used as non-stick coatings in utensils.

Question 18.
Differentiate between soaps and detergents.
Answer:
Soap :

1. It is a sodium or potassium salt of a fatty acid.
2. They are not effective in hard water.
3. These are biodegradable.
4. They form scum if hard water is used for washing.

Detergent :

1. They are made from petroleum hydrocarbons.
2. They are effective even in hard water.
3. These are non-biodegradable.
4. They do not form scum with hard water.

Question 19.
Fill in the blanks.
1. …………. and ………….. metals are normally used to make electric wires.
Answer:
Copper and aluminium metals are normally used to make electric wires.

2. Steel is an alloy of iron and ……….
Answer:
Steel is an alloy of iron and carbon.

3. …………. is used for filling spaces in food packages because it is very unreactive.
Answer:
Nitrogen gas is used for filling spaces in food packages because it is very unreactive.

4. In the laboratory,………….. wires are used to perform the flame test’to identify unknown metals or metalloids.
Answer:
In the laboratory, platinum wires are used to perform the flame test’to identify unknown metals or metalloids.

5. ………….. are metals used for packing food materials.
Answer:
Aluminium (foils) are metals used for packing food materials.

6. ………….. is used for plating steel cans used as food containers.
Answer:
Tin is used for plating steel cans used as food containers.

7. ………….. is also called as quicksilver and used in thermometers.
Answer:
Mercury is also called as quicksilver and used in thermometers.

8. ………… is used in fireworks because it burns with a dazzling white light in powder form.
Answer:
Magnesium is used in fireworks because it bums with a v dazzling white light in powder form.

9. ………….. is an essential element in amino acids that make up proteins.
Answer:
Nitrogen is an essential element in amino acids that make up proteins.

10. To remove cataract from eyes, eye surgeons use a ………. blade.
Answer:
To remove cataract from eyes, eye surgeons use a diamond i blade.

11. …………. is the hardest substance known.
Answer:
Diamond is the hardest substance known.

12. ………….. forms the backbone of many important biomolecules such as fats, carbohydrates and proteins.
Answer:
Carbon forms the backbone of many important biomolecules such as fats, carbohydrates and proteins.

13. ………….. is the most important industrial acid and called the king of chemicals.
Answer:
Sulphuric acid is the most important industrial acid and called the king of chemicals.

14. ………….. is used in converting vegetable oil to vegetable ghee.
Answer:
Hydrogen is used in converting vegetable oil to vegetable ghee.

15. ………….. is a noble gas which is used in lighthouse lamps.
Answer:
Xenon is a noble gas which is used in lighthouse lamps.

16. …………… All organic compounds are based compounds.
Answer:
All organic compounds are carbon based compounds.

17. Common salt is chemically called as ……….
Answer:
Common salt is chemically called as sodium chloride.

18. ……………. acid is present in the digestive juices of the human stomach.
Answer:
Hydrochloric acid is present in the digestive juices of the human stomach.

19. ………… is used in the manufacture of quicklime (CaO)
Answer:
Limestone (CaC03) is used in the manufacture of quicklime (CaO)

20. Plaster of Paris is obtained by heating …………. at a very low temperature.
Answer:
Plaster of Paris is obtained by heating gypsum at a very low temperature.

21. ……………. is commonly used as Philosopher’s wool.
Answer:
Zinc oxide (ZnO) is commonly used as Philosopher’s wool,

22. ………….. is used for making blackboard chalks.
Answer:
Plaster of paris is used for making blackboard chalks.

23. …………. Most nitrogeneous fertilizers are obtained from
Answer:
Most nitrogeneous fertilizers are obtained from ammonia

24. The major food groups – carbohydrate, fats and proteins are ………….. organic compounds.
Answer:
The major food groups – carbohydrate, fats and proteins are complex organic compounds.

25. Man-made chemicals used to kill or inhibit fungi or fungal spores are called
Answer:
Man-made chemicals used to kill or inhibit fungi or fungal spores are called fungicides.

26. …………. are essential body-building nutrients.
Answer:
Proteins are essential body-building nutrients.

27. ………….. are the main constituents of petroleum and natural gas.
Answer:
Hydrocarbons are the main constituents of petroleum and natural gas.

28. …………. is the simplest form of hydrocarbons.
Answer:
Methane is the simplest form of hydrocarbons.

29. Any substance which has cleaning properties in water is called a ………….
Answer:
Any substance which has cleaning properties in water is called a detergent.

30. Quinine and chloroquine arc ………….. medicines.
Answer:
Quinine and chloroquine are antimalarial medicines.

31. …………. acts as both antipyretic and analgesic.
Answer:
Aspirin acts as both antipyretic and analgesic.

32. Antibiotics are ineffective against …………..
Answer:
Antibiotics are ineffective against viruses.

33. Silk and cotton are …………… fibres but rayon, nylon are …………. fibres.
Answer:
Silk and cotton are natural fibres but rayon, nylon are synthetic fibres.

34. ……………. is a mixture of copper sulphate and slaked lime and used as a fungicide.
Answer:
Boardeaux mixture is a mixture of copper sulphate and slaked lime and used as a fungicide.

35. …………… is a material that can be shaped by applying heat or pressure.
Answer:
Plastic is a material that can be shaped by applying heat or pressure.

26. …………… are a homogeneous mixture of a solute and a solvent.
Answer:
Solutions are a homogeneous mixture of a solute and a solvent.

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ICSE Class 7 Chemistry Important Questions