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Give reason:
A burning candle stops burning if covered with a glass tumbler
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Give reason:
Mountaineers and divers carry oxygen cylinders with them.
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Give reason:
When water is heated, we see bubbles rising up.
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What are the two necessary conditions for rusting of iron?
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Give the chemical name of rust.
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State the full form of LPG and CNG? How are the two different in their composition?
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Plants and animals maintain the balance of carbon ___________and _________ in the air.
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The supporter of combustion in air is _____.
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Green plants need ________________to prepare food.
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Oxygen is used in ___________the food to get _______.
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Aquatic plants and animals use _________ in water.
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The reddish-brown powder on the surface of iron nails exposed to air and moisture is called _____.
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Write ‘true’ or ‘false for the following;
Carbon dioxide is given out during photosynthesis
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Write ‘true’ or ‘false for the following;
The major component of air is oxygen.
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Write ‘true’ or ‘false for the following;
The composition of air was discovered by Lavoisier.
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Name the components of air with their approximate percentage by volume in air. Does the percentage by volume of each component remain the same, in the atmosphere of different parts of the world? Explain with reasons.
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With the help of a labeled diagram, describe a simple experiment to show the presence of oxygen and nitrogen in air using a piece of white phosphorus.
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You are given a test tube with two outlets and a bottle of lime water. Using same, how would you demonstrate experimentally the presence of carbon dioxide in air.
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Give a reason why water droplets appear on the outer surface of a tumbler containing ice.
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Explain the importance of nitrogen of the air for plant growth.
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