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I. Tick the correct answer.1. The major part of the air is constituted by (a) Hydrogen (b) argon (c) water vapour (d) nitrogen 2. Which of the following gas helps in burning? (a) nitrogen (b) Oxygen (c) carbon dioxide (d) carbon monoxide 3. Which is not a property of air? (a) It is transparent (b) it occupies space (c)it is opaque (d) it is colourless 4.The burning of fuel releases ________________ a) oxygen b) nitrogen c) carbon dioxide d) argon 5. The wind does not help in the movement of which of the following? a) fan b) firki c) windmill d) kite II. Fill in the blanks 1.The layer of air that surrounds the earth is called _________________. 2. Air in motion is called ________________. 3. A ______________shows the direction in which the air is moving at that place. 4 .Plants give out oxygen during a process called _____________. 5. Nitrogen is needed by plants to make _________________. III. Write true or false 1 Oxygen supports burning process. ( ) 2.Air does not help in the dispersal of seeds. ( ) 3.Smoke is produced by the burning of fuels. ( ) 4. Nitrogen and water vapour make up 99% of air. ( ) 5. Air is transparent. ( ) 1. Name the major component of air. 2. State any two properties of air. 3. How will you show that air supports burning? 4. Why do policemen regulating traffic at a crowded city road often wear masks? 5. State any five uses of airplz answer all question |
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Answer» Answer:1a. nitrogen 1b. oxygen 1c. it is opaque 1d. carbon dioxide 1e. fan 2a. atmosphere 2b. wind 2c. wind vane 2d. respiration 2e. dna, proteins and chlorophyll 3a. true 3b. false 3c. true 3d. false 3e. true 1. The major component of air is nitrogen 2. We can show this by conducting an experiment. 1- Take a small candle and a transparent glass. 2- light the candle and put the glass on top of it. Make sure that there aren't any OPENINGS for air to enter. You will see that in a few seconds, the candle stops burning. Now try it with a larger glass and repeat steps 1 and 2. You will see that now the air takes a LITTLE while longer. This proves that air supports burning. 4. Traffic Police wear a mask because they spend their whole day between vehicles and dust. The releasing of gas and EXHAUSTS from cars is a danger to their health and causes health issues. 5. 1- Air helps in maintaining the temperature on the earth’s surface by circulating hot and cold air. Air acts as a conductor of heat. 2- Oxygen present in the air is one of the main life sustaining gas 3- Air which consists of energy is one of the main suppliers of energy. Oxygen particles in the air get absorbed by the lungs help in breaking down food particles. These food particles then later release energy. 4- Another use of air is that it supports burning or combustion 5- Carbon dioxide which is also a component of air is used by plants during the process of photosynthesis and oxygen, water vapor is released by plants as a by-product. Apart from these gases, other gases are also useful such as nitrogen is used in the production of AMMONIA. |
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