9-9-08[lecture3]si - CHEM 116 IN CLASS NOTES(SI TOPICS...

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CHEM 116
IN CLASS NOTES: 09-09-08 (SI)
TOPICS COVERED
1. Kinetic Molecular Theory
2. Graham’s Law of effusion
Conclusion from Clicker question
1. The higher the temperature, the faster the particles of a gas move
2. Increase in temperature leads to increase in the speed of the particles.
3. Particles of a particular gas at certain temperature and pressure do have a wide distribution of
the speeds of the particles. This is because some particles are fast and others are small and their
speeds change all the time.
4. Particles in different gases at the same temperature have different speeds, the heavier the
particle the slower it is and the lighter the particle, the faster it is.
5. Average velocity cannot be used to solve for speed, instead Root- mean square (r.m.s) speed
should be used.
Average Mean Velocity vs. Root Mean Square Velocity (r.m.s)
Kinetic Molecular Theory
Can use this theory to predict the r.m.s speed of a gas.