2. Speed of Gases

3. Root Mean Square Speed of Gases
R = J *K / mol
J = 1kg * m2 / s2
MM = molar mass

4. Problem page 186
Calculate the root mean square speed of molecular chlorine in m/s at 20 C.

5. Determining Molecular Speed

6. Speed calculations don’t seem to match reality……….. Why????
Gas diffusion
Speed calculations don’t seem to match reality……….. Why????

7. Speed calculations don’t seem to match reality……….. Why????
Gas diffusion
Speed calculations don’t seem to match reality……….. Why????

8. Deviation from ideal behavior
Gases have some volume in the container
Molecules are attracted to each other

9. Deviation from ideal behavior
Gas molecules take up some volume in the container
Molecules are attracted to each other
For most general calculations, these differences are minute and do not effect the results.
For more accuracy, we use Van der Waals equation

10. Van der Waals equation

11. Van der Waals equation

12. Problem on Page 191
Using the data shown in the table, calculate the pressure exerted by 4.37 moles of molecular chlorine confined in a volume of 2.45 L at 38 C. Compare the pressure with that calculated using the ideal gas equation.
PV = nRT