AP Chemistry / Unit 3: Properties of Substances and Mixtures
3.5 Kinetic Molecular Theory
Notes
Gas particles move randomly and collide elastically; their volume is negligible.
- Average kinetic energy is proportional to kelvin temperature.
- At the same temperature, lighter molecules move faster.
Practice
At the same temperature, which moves fastest on average?
Lowest molar mass.
Average kinetic energy of a gas depends on:
$KE\propto T$.
Raising temperature makes the Maxwell-Boltzmann curve:
More spread, faster on average.
Ready for more? Take the Unit 3 test.