1. Intermolecular Forces
Reviewing what we know
Gases
Solids
Low density
Highly compressible
Fill container
High density
Slightly compressible
Rigid (keeps its shape)

2. Intermolecular Forces
Intermolecular forces – occur between molecules
Intramolecular forces – occur inside the molecules

3. Intermolecular Forces
Dipole – dipole attraction

4. Intermolecular Forces
Hydrogen Bonding
Occurs between H and highly electronegative atom (for example N, O, F)

5. Intermolecular Forces
Hydrogen Bonding
Affects physical properties
Boiling point

6. Water and Its Phase Changes
Heating/cooling curve

7. Water and Its Phase Changes
Normal boiling point – at 1 atm = 100oC
Normal freezing point – at 1 atm = 0oC
Density
Liquid water = 1.00 g/mL
Ice = g/mL

8. Boiling Point and Vapor Pressure

9. The Solid State: Types of Solids

10. Solids / Liquids
calorie – Amount of energy required to raise the temperature of 1 gram of H2O by 1oC
1 calorie = joules

11. Specific heat capacity (c) – The
amount of energy required to
change the temp. of 1 gram of a
substance by 1oC.

12. H = mcDT H = heat m = mass c = specific heat constant
DT (delta T) = temperature change Tf - Ti

13. c - liquid H2O = 1.0 cal/gm (4.184 j/gm)
c - ice H2O = 0.5 cal/gm (2.092 j/gm)
c - steam H2O = 0.5 cal/gm (2.092 j/gm)

14. H = Hf . m H = heat Hf = heat of fusion
Hf for H2O = 80 cal/gm ; J/gm
m = mass

15. H = Hv . m H = heat Hv = heat of vaporization
Hv for H2O = 540 cal/gm ; J/gm (2.3 kJ/gm)
m = mass

16. H2O Phase Change Temp (oC) Time Solid H=mcDT Liquid Gas H=Hv*m
Vaporize
100
Condense
No temperature change occurs while: melting, freezing, vaporizing, condensing
H=Hf*m
Melt
Freeze