6th Grade > Chemistry
AIR AROUND US MCQs
Total Questions : 100
| Page 5 of 10 pages
Answer: Option A. -> True
:
A
Carbon dioxide fire extinguishers are being used extensively. When sprayed, it forms a layer on the fire thereby cutting off the supply of oxygen. Carbon dioxide also spreads very fast and helps in the cooling of the combustible substance. By reducing the heat and cutting off oxygen supply it extinguishes the fire.
:
A
Carbon dioxide fire extinguishers are being used extensively. When sprayed, it forms a layer on the fire thereby cutting off the supply of oxygen. Carbon dioxide also spreads very fast and helps in the cooling of the combustible substance. By reducing the heat and cutting off oxygen supply it extinguishes the fire.
Answer: Option A. -> Oxygen
:
A
Oxygen is the colourless, odourless gas which supports combustion. Rest of the gases given here don't support combustion.
:
A
Oxygen is the colourless, odourless gas which supports combustion. Rest of the gases given here don't support combustion.
:
Activities : 1 Mark each
The activities which are possible due to the presence of air are:
(a) Respiration in animals and plants
(b) Sailing of boats, airplanes
(c) Burning of any substance
(d) Photosynthesis in plants
(e) Power generation from wind mills
:
Making tea.
Rustling of leaves and flying of kite needair whereas making of tea has nothing to do with moving air.
:
1Mark each
Air pollution can be prevented as follows:
(i) By using smokeless sources of energy like solar energy and electrical energy.
(ii) By using filters for the smoke coming out of the chimneys of factories and power plants.
(iii) By using internal combustion engines in vehicles for complete and efficient burning of fuel.
:
Definition : 1Mark
Conditions: 2 Marks
Rusting is the process in which iron slowly reacts with oxygen in the air in the presence of moisture to form a flaky brown substance called rust.
The two most important conditions of rusting are:
(i) Presence of oxygen (air)
(ii) Presence of moisture
:
Name of the gas: 1Mark
Source:1Mark
Living organisms require oxygen for respiration.
They get oxygen from the atmosphere. The envelope of air around us is called atmosphere and 20% of it is oxygen.
:
In a mixture, the components can easily be separated and they also retain their properties.
The main constituents of air are nitrogen, oxygen, water vapour and carbon dioxide, and they all can easily be separated with their properties being unchanged or altered.
:
Atmosphere is the envelope of gases surrounding the Earth.
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