1. Objective:
Define vapor pressure and analyze vapor pressure curves
Define boiling point, determine boiling points from vapor pressure curves and relate vapor pressure to IM Forces

2. Open Container Vaporization:
In an open container, liquids will vaporize from the surface until all the liquid is gone …

3. Closed Container Vaporization:
In a closed container, liquids still vaporize, but can’t escape …
Vapor particles build up inside
and start to re-condense …
At some point, the rate of evap. = rate of conden.

4. Closed Container Vaporization:
When the rates are equal, the amount of water stays constant …
and the amount of water vapor stays constant …
The two states of matter are in equilibrium with each other!!!

5. Closed Container Vaporization:
The PH2O can be measured at this point and recorded …
(assume 25oC)
This is the VAPOR PRESSURE!
The two states of matter are in equilibrium with each other!!!

6. Closed Container Vaporization:
If eqm is achieved and THEN the water is heated …
More molecules are forced to vaporize and eqm is re-achieved, but with more vapor present

7. Closed Container Vaporization:
Vapor pressure vs. temperature can be graphed to create …

8. Vapor Pressure Curve
What will the equilibrium vapor pressure be over a sample of water at 65oC?

9. Now continue heating …
What will happen to this water at 100oC?

10. Boiling Point: temperature when the vapor pressure is equal to atmospheric pressure

11. What is the boiling point of water at sea level where the pressure is 1 atm?

12. What is the boiling point of water on Mt
What is the boiling point of water on Mt. Everest where the pressure is 0.65 atm?

13. Molecular view of boiling:
The point when ALL particles in the liquid have enough KE to escape the IM Forces and vaporize (does not just happen at the surface)
Intermolecular Forces connection:
Substances with stronger IM forces will have lower VP’s

14. Solid State Chemistry Background Knowledge Research
Work in groups of 2-3
Research the type of solid that is on your card
Due at end of period
Lab grade for today