Characteristics of Gases
Gases (like air, oxygen, smoke) have no fixed shape and no fixed volume. They fill the entire space available to them.
Particle Arrangement
- Packing: Particles are very far apart. Large interparticle spaces.
- Forces: Attraction is negligible (very weak).
- Movement: Particles move freely and randomly at high speeds.
- Compressibility: Very High.
Activity: The Syringe Experiment
If you take a syringe, close the nozzle, and push the piston:
- Solid (Chalk): Cannot push.
- Liquid (Water): Cannot push.
- Gas (Air): Can push easily! This proves gases have large empty spaces that can be reduced by pressure.
Diffusion
Diffusion is the spreading out and mixing of a substance with another substance due to the motion of its particles.
- Example: Burning an incense stick in one corner makes the whole room smell good. The smoke particles collide with air particles and spread rapidly.