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प्रश्न
A mixture has a variable composition. Give three other reasons why air is considered a mixture and not a compound.
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उत्तर
Air is a mixture because :
- Air has no formula, a mixture has no formula whereas the compound has a formula.
- No energy changes are involved to form air from various gases.
- When air is formed out of its constituents no change in mass nor change in volume takes place.
- Properties of air vary from place to place and from time to time. i.e. there is more CO2 in towns as compared to villages where more oxygen prevales as compared to towns.
- Components of air can be separated by simple physical methods.
संबंधित प्रश्न
What do you observe when a burning candle is covered with an inverted jar.
State two similarities and two differences between respiration and burning.
Water does not have a ______ but has definite ______ and ______.
Why is it said that-
Air is a homogeneous mixture of various gases.
What will happen if the amount of water vapour in the air increases.
Match the statements in List I with the correct answer from List II.
| List I | List II |
| 1. The constituent of air which is around 0.02% | A: Nitrogen |
| 2. The constituent of air which is inert or unreactive | B: Oxygen |
| 3. The constituent of air which is non-combustible, but supports combustion. |
C: Sulphur dioxide |
| 4. A pollutant in air responsible for acid rain | D: Carbon dioxide |
| 5. The main rare gas present in air. | E: Argon |
Fill in the blank:
Rusting is a chemical reaction which involves _____ oxidation.
What should be done if the clothes of a person catch fire accidentally? Why?
About 78% of the volume of air is ______.
Explain the following observations very briefly
A firki does not rotate in a closed area.
