1. States of Matter

2. Heat vs. Hot
Heat is a form of energy and is measured in joules or calories
Hotness is measured as temperature
Temperature is directly proportional to kinetic energy

3. Temperature and Kinetic Energy
Temperature is directly proportional to Kinetic Energy of the particles
Kinetic Energy (energy of particle motion) = ½ mv2 where m is mass of particle and v is velocity of particle
ALL PARTICLES ARE MOVING AT ALL TEMPERATURES ABOVE ABSOLUTE ZERO

4. Distribution of Energies
Individual particles’ energies vary. Temperature depends on the average kinetic energy of all the particles.

5. Phase Changes
Phase changes involve a change in Potential Energy, not Kinetic Energy
THERE IS NO CHANGE IN TEMPERATURE UNTIL THE ENTIRE SAMPLE HAS COMPLETED PHASE CHANGE

6. Endothermic Phase Changes
Heat must be absorbed by sample (Surroundings get cold as heat is transferred INTO system)
Melting: solid to liquid
Sublimation: solid to gas
Vaporization: liquid to gas

7. Exothermic Phase Changes
Material releases heat to the surroundings. (Surroundings get hot as heat is transferred from the system.)
Condensation: gas to liquid
Deposition: gas to solid
Freezing: liquid to solid

8. Forces of Attraction Strongest to Weakest
InTERmolecular
4. Hydrogen bonds
Polar Compounds with H
5. Dipole-Dipole
Polar with no H
6. (London) Dispersion Forces
Nonpolar
InTRAmolecular
1. Ionic
2. Metallic
3. Covalent
The stronger the force, the more energy it takes to break it.

9. Heat and Phase Change Calculations
Freezing and Melting
The energy required to melt 1 mole of a substance is called the molar heat of fusion.
The energy released by freezing 1 mole of a substance is the molar heat of fusion.

10. Heat and Phase Change Calculations
Vaporizing and Condensing
The energy required to convert 1 mole of a liquid substance to gas is the molar heat of vaporization.
The energy released by when 1 mole of gas condenses to liquid is the molar heat of vaporization.

11. Example Problem 1
Calculate the energy required to melt 8.5 g of ice at 0° C. The molar heat of fusion for ice is 6.02 kj/mol.
8.5 g H2O x 1 mol H2O x kj = 2.8 kj
g H2O mol H2O

12. Example Problem 2
Calculate the energy released when 25 g of steam at 100.°C condenses and cools to 55° C. The molar heat of vaporization is 40.6 kj/mol.
Process 1: Condensation
25 g H2O x 1 mol x 40.6 kj = 57 kj released
g mol
Process 2: Cooling
Q = mCΔt
(25 g) ( 4.18 j/g°C) ( 55°-100.°C) = 4700 j released
Total Energy Released = 57 kj kj = 62 kj