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Question
A mixture has a variable composition. Give three other reasons why air is considered a mixture and not a compound.
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Solution
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.
RELATED QUESTIONS
Match the statements in Column A, with those in Column B.
| Column A | Column B |
| 1. Largest Constituent of air, which dilutes the activity of oxygen. | (a) Oxygen |
| 2. A gas used for filling weather observeation balloons. | (b) Carbonic acid |
| 3. An acid formed by the dissolution of sulphur dioxide gas in water. | (c) Sulphuric acid |
| 4. An acid formed by the dissolution of carbon dioxide in water. | (d) Helium |
| 5. A gas vital for respiration. | (e) Nitrogen |
Give two uses of the following component present in air:
nitrogen
State two similarities and two differences between respiration and burning.
How is air useful to scooters and cars.?
Name two air pollutants which cause global warming.
Write ‘true’ or ‘false for the following;
Air is a compound.
Tick (√) the correct alternative from the choice given for the following statement.
Air pollution is due to the
Name the following.
Inert gases in the air
Answer in your own words.
What are the various constituents of air? Write their uses.
Fill in the blank:
Rusting is a chemical reaction which involves _____ oxidation.
