6th Grade > Chemistry
AIR AROUND US MCQs
Total Questions : 100
| Page 9 of 10 pages
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Oxygen.
Nitrogen and carbon dioxide both do not support combustion whereas oxygen does.
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Scuba divers carry cylinders containing oxygen because they cannot utilise the oxygen dissolved in water for respiration.
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Name of the process : 1 Mark
Explanation : 1 Mark
Winnowing is an agricultural method developed by ancient people for separating grain from chaff.
This separation is done by blowing air through the grains and allowing the wind or a forced current of air to blow away chaff and impurities which are lighter than the grains.
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Name of the process : 1 Mark
Explanation : 1 Mark
Winnowing is an agricultural method developed by ancient people for separating grain from chaff.
This separation is done by blowing air through the grains and allowing the wind or a forced current of air to blow away chaff and impurities which are lighter than the grains.
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Correct Answer : 1 Mark
Use : 1 Mark
Oxygen and carbon dioxide.
Plants use carbon dioxide for photosynthesis and oxygen for respiration.
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Each Point : 1 Mark
1. Moisture determines the Earth’s climatic conditions.
2. The presence of water vapour in the air causes rain.
3. It controls the rate of evaporation from the bodies of plants and animals.
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Experiment : 3 Marks
Diagram : 2 Marks
Fill a glass vessel or a beaker with water. Place the beaker on the tripod over the burner. Let the water in the beaker heat slowly. Now look at the inner surface of the vessel before the water starts boiling, you will be able to see tiny bubbles on the inside. This happens because, on heating water, the air dissolved in the water escapes in the form of bubbles.
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Experiment : 3 Marks
Diagram : 2 Marks
Fill a glass vessel or a beaker with water. Place the beaker on the tripod over the burner. Let the water in the beaker heat slowly. Now look at the inner surface of the vessel before the water starts boiling, you will be able to see tiny bubbles on the inside. This happens because, on heating water, the air dissolved in the water escapes in the form of bubbles.
Answer: Option A. ->
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a) 2 Marks
b) 2 Marks
c) 1 Mark
a) The oxygen content decreases as we move to high altitudes like mountains, so mountaineers carry oxygen cylinders with them to breathe there.
b) Burning of some material releases smoke that contains few gases and fine dust particles that is harmful, thus we feel suffocation in a closed room, where some material is burning.
c) This is done so that the harmful gases and smoke of factories are released at a height away from us.
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a) 2 Marks
b) 2 Marks
c) 1 Mark
a) The oxygen content decreases as we move to high altitudes like mountains, so mountaineers carry oxygen cylinders with them to breathe there.
b) Burning of some material releases smoke that contains few gases and fine dust particles that is harmful, thus we feel suffocation in a closed room, where some material is burning.
c) This is done so that the harmful gases and smoke of factories are released at a height away from us.
Answer: Option A. ->
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Definition : 1 Mark
Causes : 2 Marks
Air pollution occurs when harmful substances including particulates and chemicals are introduced into Earth's atmosphere. It may cause diseases, allergies or death of humans; it may also cause harm to other living organisms such as animals and food crops, and may damage the natural or built environment.
Volcanic eruption, crop pollination and human activities like burning of coal, wood, diesel oil, petrol, kerosene, etc. are the major causes of air pollution.
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Definition : 1 Mark
Causes : 2 Marks
Air pollution occurs when harmful substances including particulates and chemicals are introduced into Earth's atmosphere. It may cause diseases, allergies or death of humans; it may also cause harm to other living organisms such as animals and food crops, and may damage the natural or built environment.
Volcanic eruption, crop pollination and human activities like burning of coal, wood, diesel oil, petrol, kerosene, etc. are the major causes of air pollution.
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Observation : 1 Mark
Reason : 2 Mark
When a bottle containing cold drink is opened, bubbles can be seen coming out with a fizzing sound.
Cold drinks contain dissolved CO2 at high pressure. When we open a bottle of cold drink, the dissolved CO2 gushes out in the form of bubbles with a fizzing sound due sudden decrease in pressure. The fizzing sound is because of sudden release of CO2.
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