Please answer to my question
fastly
Answers
Answer:
Ans1)Air is a mixture of 79% nitrogen, 20% oxygen, 1% carbon dioxide, water vapours and some other gases. Air also contains dust particles.
2)Nitrogen
3)
Answer:
Ans:-1)Air is composed of nitrogen gas,oxygen gas,carbon dioxide,water vapour,other gases,dust particles etc.
Ans:-2)Oxygen is the gas present in the atmosphere essential for respiration.
Ans:-3)Deseription-two small candles of same size is fixed on two glass plates.The glass plates now filled up with water candles are lighted and one candle is converted within inverted class.
Observation-it is observed that the candle,which is not covered continues burning but the candle which is covered by a glass goes off after sometime and water level inside that class is increased.
Conclusion-From this activity,it can be concluded that burning of anything is possible only in the presence of oxygen in the air.
Ans:-4)Take some water in a glass or metal container like pan and heat it. Just before water begins to boil, you will notice some bubbles at the inner surface of the pan. These bubbles come from the air dissolved in water. This shows that air is dissolved in water.
Ans:-5)A lump of cotton wool has a lot of air trapped inside the space present in its fibers. When this lump of cotton is immersed in water, all the air is replaced by water. Due to this, the cotton lump shrinks down.