6th Grade > Chemistry
AIR AROUND US MCQs
Total Questions : 100
| Page 10 of 10 pages
Answer: Option A. ->
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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.
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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.
Answer: Option A. ->
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Atmosphere is the envelope of gases surrounding the Earth.
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Atmosphere is the envelope of gases surrounding the Earth.
Answer: Option A. ->
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Making tea.
Rustling of leaves and flying of kite need air whereas making of tea has nothing to do with moving air.
Answer: Option A. ->
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Each property : 1 Mark
The properties of air are as follows:
1) It is transparent.
2) It supports all life forms on Earth.
3) It is colourless.
4) It occupies space.
5) It is present everywhere - on land, in water and in soil.
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Each property : 1 Mark
The properties of air are as follows:
1) It is transparent.
2) It supports all life forms on Earth.
3) It is colourless.
4) It occupies space.
5) It is present everywhere - on land, in water and in soil.
Answer: Option A. ->
:
a) 1 Mark
b) 1 Mark
c) 1 Mark
a) There is a large amount of moisture in the air on a cloudy day. So, clothes do not dry quickly on a cloudy day. The rate of evaporation is higher i.e. clothes dry quicker when the air is less humid.
b) Hydrogen is a combustible gas and forms an explosive mixture with air, so it is not advisable to fill hydrogen gas in big air balloons.
c) Since air is much heavier than helium, the air pushes the light helium balloon towards higher altitudes where the air is also lighter.
:
a) 1 Mark
b) 1 Mark
c) 1 Mark
a) There is a large amount of moisture in the air on a cloudy day. So, clothes do not dry quickly on a cloudy day. The rate of evaporation is higher i.e. clothes dry quicker when the air is less humid.
b) Hydrogen is a combustible gas and forms an explosive mixture with air, so it is not advisable to fill hydrogen gas in big air balloons.
c) Since air is much heavier than helium, the air pushes the light helium balloon towards higher altitudes where the air is also lighter.
Answer: Option A. ->
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Name of the gas : 1 Mark
Source : 1 Mark
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.
Answer: Option A. ->
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1 Mark 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.
Answer: Option A. ->
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Definition : 1 Mark
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
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Definition : 1 Mark
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
Answer: Option A. ->
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Experiment : 3 Marks
Diagram : 2 Marks
Take a candle and fix it at the center of a glass container. Add some quantity of water in the glass container. Now place an empty glass jar over it. Above the water surface, mark five lines at equal distances as depicted in the diagram below.
Carefully light the candle and wait for a few seconds. The flame will be extinguished due to the absence of oxygen. We can observe that the water level in the glass jar is 1/5 of the volume of air present in the glass jar. The above experiment proves that one part of the air present in the glass jar supports the combustion process, i.e., oxygen. Hence, 1/5th of the volume of air is oxygen. Thus, we can conclude that air contains nitrogen and oxygen in the ratio 4:1.
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Experiment : 3 Marks
Diagram : 2 Marks
Take a candle and fix it at the center of a glass container. Add some quantity of water in the glass container. Now place an empty glass jar over it. Above the water surface, mark five lines at equal distances as depicted in the diagram below.
Carefully light the candle and wait for a few seconds. The flame will be extinguished due to the absence of oxygen. We can observe that the water level in the glass jar is 1/5 of the volume of air present in the glass jar. The above experiment proves that one part of the air present in the glass jar supports the combustion process, i.e., oxygen. Hence, 1/5th of the volume of air is oxygen. Thus, we can conclude that air contains nitrogen and oxygen in the ratio 4:1.
Answer: Option A. ->
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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
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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
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