1. The Kinetic Molecular Theory
Movement in solids, liquids, and gases

2. The theory of moving molecules!
Describes the differences between gas, liquid, and solid states.

3. Assumptions within the KMT
1. Gases are made of tiny particles that are far apart from each other.
2. Gas particles are in continuous, rapid, random motion

4. More Assumptions
3. There are no attractive forces between molecules under normal conditions.
4. Collisions between particles are elastic (no energy is lost due to friction).

5. Last Assumption
5. Particles at the same temperature have the same average kinetic energy.

6. States of Matter: a review

7. KMT & Changing State of Matter
Gases- Attractions are insignificant
Liquids- Attractions are more important, leading to a more ordered state
Solids- Attractions are most important with a very ordered state!

8. KMT & Changing State
Involves adding or removing energy (changing temperature) or changing pressure.

9. KMT & Changing States of Matter
What happens, on a molecular level, when you add heat to a solid?
Molecules vibrate more rapidly
Molecules “escape” to the liquid states and slide past each other.
What happens when you boil/evaporate a liquid?
Molecules absorb more energy, move faster
Can break weak bonds that keep them liquid and “escape: into the gas state.

10. KMT and Changing State of Matter
The opposite occurs when you cool a gas down until it becomes a liquid and then cool the liquid until it solidifies.

11. What happens when we change pressure?
Pressure – the force per unit area
Volume- amount of space an object takes up
Temperature- average kinetic energy of the particles
These 3 concepts are related to each other!

12. Pressure, Volume, & Temperature
What would happen to the pressure from the molecules in the balloon if I decreased the volume?

13. Pressure & Volume Decreasing the Volume would Increase the Pressure
V P
There is an inverse relationship between pressure and volume!

14. Volume & Temperature
What would happen to the balloon if I increased the temperature?

15. Volume & Temperature
Adding heat would increase the speed of the molecules, which increases the pressure inside the balloon, which increases the volume!