Q1.
Is air a mixture? What kind of mixture is it?
Answer
Yes, air is a mixture — and it is a uniform one.
Air is made mainly of nitrogen, oxygen, argon, carbon dioxide and water vapour. These gases are simply mixed: none of them reacts with the others, and each keeps its own properties inside the mixture.
- Nitrogen makes up about 78% of air and does not take part in combustion.
- Oxygen is needed by most living beings to stay alive, and it helps in combustion.
- Water vapour is there too — when warm air touches a cool surface, the vapour turns into liquid water and tiny droplets form on the surface.
Why it is uniform: The gases are mixed particle by particle, so a sample of air taken from anywhere in this room has the same composition and behaves in the same way. You cannot see or point out the nitrogen apart from the oxygen even with a microscope.
Tip: Dust and smoke floating in air are not part of the mixture we call air — they are pollutants, and they are the reason a sunbeam through a small opening looks full of shining specks.