1. Evaporation Vaporization = conversion of a liquid to a gas or vapor
Evaporation = transition from a liquid to a gas BELOW a substances boiling point
Some of the liquid particles have enough kinetic energy to overcome the forces of attraction around them and escape into the gas phase

2. Vapor Pressure
Amount of pressure gas particles are exerting on the surface of the liquid (to escape to the air)

3. Temperature and Vapor Pressure
The higher the temperature the faster the particles are moving
The faster the particles are moving the higher the vapor pressure
Low Temp
High Temp

4. Liquid/Vapor Equilibrium
The point at which (in a closed container) the rate of evaporation is equal to the rate of condensation

5. STP Standard Temperature Standard Pressure
STP = Standard Temperature and Pressure
Standard Temperature
0 °C or 273 K
Standard Pressure
1 atmosphere (atm) kilopascals (kPa) 760 Torr (mmHg)

6. Boiling Point
Atmospheric Pressure
Temperature at which vapor pressure  = atmospheric pressure 
Normal boiling point is at standard pressure (Water = 100 °C)
Boiling point is lower at higher elevations (there is less gas above them)
Vapor Pressure
V.P. = A.P.

7. Boiling Point Atm Pressure Atm Pressure Atm Pressure Vapor Pressure
70 ºC
100 ºC
25 ºC
Atm Pressure
Atm Pressure
Atm Pressure
Vapor Pressure
Vapor Pressure
Vapor Pressure

8. How would a change in elevation affect boiling point
How would a change in elevation affect boiling point? Would water boil at 100 ºC on a mountain?
Boiling point is lower at higher elevations (there is less gas above them; lower atmospheric pressure)

9. Altitude and Boiling Point

10. As the temperature of a liquid increases, its vapor pressure
iRespond Question F
Multiple Choice
A.) decreases
B.) increases
C.) remains the same
D.)
E.)

11. As the pressure on the surface of a liquid decreases (atmospheric pressure), the temperature at which the liquid will boil
iRespond Question F
Multiple Choice
A.) decreases
B.) increases
C.) remains the same
The atmospheric pressure is lower, meaning that the vapor pressure will be lower, and will cause boiling to occur at a lower temperature
D.)
E.)

12. Thermochemistry & Phases Test
Phase Changes
Energy transformations
Conservation of Energy
Endothermic/Exothermic reactions
Temperature conversions (memorize K = ºC+ 273)
Heat & Temperature
Heat Flow
Calorimetry problems
Interpret potential energy diagrams
Thermochemical Stoichiometry
(Mole ↔ Energy)
Properties of 3 Phases
Names of Phase Changes
Endothermic/Exothermic Phases Changes
Energy Changes During Phase Changes
Heat of Fusion/Vaporization Calculations
Dynamic Equilibrium During Phase Changes
Vapor Pressure
Boiling (Changes Using Elevation or Pressure)
Interpreting Heating Curves

13. Relationship between intermolecular forces and boiling point
The stronger the intermolecular forces the less vapor pressure; higher boiling point (it requires more heat energy to overcome the attraction between the molecules)
Water has strong intermolecular forces and has a high boiling point (low V.P.)
Gasoline has weak intermolecular forces and has a low boiling point (high V.P.)

14. What is the boiling point of water at 70 kPa?
What do all of the curves have in common?
Which substance has the weakest intermolecular forces?
What is the vapor pressure of propanone at 25 C?
What is the normal boiling point of water?
What pressure is needed for ethanoic acid to boil at 110 C?

15. Phase Diagrams
A way to represent the various phases of a substance and the conditions under which each phase exists.
A phase diagram is a plot of pressure (P) vs temperature (T).
Lines on the diagram represent conditions (T,P) under which a phase change is at equilibrium. That is, at a point on a line, it is possible for two (or three) phases to coexist at equilibrium.
Other regions of the plot, only one phase exists at equilibrium

16. Triple Point – temperature and pressure at which all 3 phases exist in equilibrium
Critical Point - At a temperature above the critical temperature, Tc, and a pressure above the critical pressure, Pc, it is no longer possible to distinguish between the gas and liquid phases. At T > Tc and P > Pc the substance is referred to as a super-critical fluid.