1. What Creates Pressure in a Gas?
The pressure of a gas comes from the continuous collisions of gas molecules with the walls of the container. Each time a molecule hits the wall, it exerts a tiny force. The combined effect of millions of such collisions per second produces measurable pressure.
2. Role of Molecular Motion
Gas molecules move very fast in random directions. Because of this random motion, they constantly strike the container walls.
2.1. Key Idea
Faster molecules → more force on the walls → higher pressure.
2.2. Example
When a gas-filled balloon is heated, the balloon expands because the molecules move faster and push outward more strongly.
3. Pressure Depends on Collision Frequency
The pressure increases if molecules hit the walls more often or with more force. This can happen due to higher speed, more molecules, or smaller container volume.
3.1. Ways to Increase Collision Frequency
- Increase temperature → molecules move faster.
- Decrease volume → molecules have less space and hit walls more often.
- Add more gas → more molecules means more collisions.