8th Standard Syllabus & Materials
8th Standard
TN 8th Tamil இயல் 3 - கல்வி கரையில - வினைமுற்று Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 2 - ஈடில்லா இயற்கை - மயங்கொலிகள் Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 2 - ஈடில்லா இயற்கை -பட்டமரம் Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 2 - ஈடில்லா இயற்கை - இயற்கையை போற்றுவோம் Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 1 - தமிழ் இன்பம் - ஆழிக்கு இணை Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 2-ஈடில்லா இயற்கை - திருக்குறள் Important Questions And Answers Study Material - QB365 Set A
Published on: 04/10/2019
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Download Tamil Nadu 8th Standard Science question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
Questions + Answers key
Take MCQ Science Test1.
Which of the following is known as azote?
Oxygen
Nitrogen
Sulpher
Carbon dioxide
2.
Solvay process is a method to manufacture
lime water
aerated water
distilled water
sodium carbonate
3.
Aerated water contains
air
oxygen
carbon dioxide
nitrogen
4.
Which of the following is true about oxygen?
Completely burning gas
Partially burning gas
Doesn’t support burning
Supports burning
5.
Dry ice is used as a _________.
6.
Nitrogen is ________ than air.
7.
______ is called as vital life
8.
Dry ice
9.
Carbon dioxide
10.
Oxygen
11.
Nitrogen
12.
What is dry ice? What are its uses?
13.
What is global warming?
14.
List out the uses of nitrogen
15.
What are the sources of oxygen?.
16.
How do astronauts breathe when they go beyond earth’s atmosphere?
17.
Why does the fish die when it is taken out of water
18.
Soda bottle bursts sometimes when it is opened during summer. Why?
19.
What are the effects of acid rain? How can we prevent them?
20.
Name the compounds produced when the following substances burn in oxygen.
a) Carbon
b) Sulphur
c) Phosphorous
d) Magnesium
e) Iron
f) Sodium
1.
(b)
Nitrogen
2.
(d)
sodium carbonate
3.
(c)
carbon dioxide
4.
(d)
Supports burning
5.
( )
refrigerent
6.
( )
lighter
7.
( )
Oxygen
8.
Refrigerator
9.
Fire extinguisher
10.
Respiration in living animals
11.
Fertilizer
12.
Solid carbon dioxide is called dry ice.
Uses:
(i) It is used as a refrigerant
(ii) The gas is so cold that moisture in the air condenses on it, creating a dense fog used in stage shows for movie effects.
13.
The increased green house effect is caused due to increase in the air pollutants and it results in the average increase of temperature of the atmosphere. This is Global warming.
14.
Uses of Nitrogen
(i) Liquid nitrogen is used as a refrigerant.
(ii) It provides an inert atmosphere for conducting certain chemical reactions.
(iii) It is used to prepare ammonia (by Haber's process) which is then converted into fertilizers and nitric acid.
(iv) It is used for inflating tyres of vehicle.
(v) It is used for filling the space above mercury in high temperature thermometer to reduce the evaporation of mercury
(vi) Many explosives such as TNT, nitroglycerin and gun powder contain nitrogen.
(vii) It is used for the preservation of fresh foods, manufacture of stainless steel, reducing fire hazards and as part of the gas in incandescent light bulbs.
15.
16.
Spacesuits contain oxygen cylinders and the astronauts carryout artificial respiration to breathe when they go beyond earth's atmosphere. In long term stay in space, Electrolysis of water helps them to generate oxygen.
17.
i) Gills which are the respiratory organs of fishes can only absorb the oxygen dissolved in water. They cannot absorb atmospheric oxygen.
ii) When fishes are taken out of water, they die as cannot breathe the atmospheric oxygen.
18.
The coefficient of expansion of gases is large. The gas in the bottle expands to high temperature in summer. Hence the pressure inside the bottle increases. So it bursts when it is opened during summer.
19.
Effects of Acid rain
(i) It irritates eyes and skin of human beings
(ii) It inhibits germination and growth of seedlings
(iii) It changes the fertility of the soil, destroys plants and aquatic life.
(iv) It causes corrosion of many buildings, bridges etc.
Preventive measures
(i) Minimising the usage of fossil fuels such as petrol, diesel etc.
(ii) Using CNG (Compressed Natural Gas)
(iii) Using non-conventional source of energy
(iv) Proper disposal of the industrial wastes.
20.
a) Carbon - Carbondioxide CO2
b) Sulphur - Sulphur dioxide SO2
c) Phosphorous - Phosphorous trioxide P2O3
Phosphorous pentoxide P2O5
d) Magnesium - Magnesium Oxide MgO
e) Iron - Iron oxide Fe3O4
f) Sodium - Sodium Oxide Na2O
8th Standard Syllabus & Materials
8th Standard
TN 8th Tamil இயல் 3 - கல்வி கரையில - பாடறிந்து ஒழுகுதல் Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 3-கல்வி கரையில - பல்துறைக் கல்வி Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 3-கல்வி கரையில - புத்தியைத் தீட்டு Important Questions And Answers Study Material - QB365 Set A
NEW8th Standard
TN 8th Tamil இயல் 2 - ஈடில்லா இயற்கை - தமிழர் மருத்துவம் ( நேர்காணல்) Important Questions And Answers Study Material - QB365 Set A
Tamilnadu Stateboard 8th Standard Subjects
Tamilnadu Stateboard Standards
