1. Section 2
Changes of State

2. What you’ll learn?
Define and compare thermal energy. Relate changes in thermal energy to changes of state.

3. Why is it important?
Matter changes state as it heats up or cools down….

4. New Vocabulary: Thermal energy Temperature Heat Melting Freezing
Vaporization
Condensation
Specific heat

5. What makes matter changes from one state to another?
ENERGY-ability to do work
Kinetic Energy
Potential Energy
- Energy in motion
Energy at rest

6. Thermal Energy?
The total kinetic energy of all the particles in a sample of matter.
-depends upon the number of particles and amount of energy

7. Temperature:
The average kinetic energy of the individual particle. (degree of coldness and hotness of a body)

8. Heat:
The transfer of thermal energy from a substance at a temp. to a temp.

9. Specific Heat?
The amount of heat that is required to raise the temperature of 1 gram
of a substance to 1 ° C.

10. CHANGES BETWEEN SOLID & LIQUID STATE
MELTING: Change from solid to liquid Melting point of H2O - 0°C FREEZING: Change from liquid to solid Freezing point of H2O- 0°C
By absorbing & releasing heat

11. MELTING POINT FREEZING POINT
- temp. at which a substance changes from solid to liquid.
FREEZING POINT
- temp. at which a substance changes from a liquid to solid.

12. 2. CHANGES BETWEEN THE LIQUID AND GAS STATE
BOILING
Takes place below the surface of a liquid.
Boiling Point:
-temp. at which liquid boils
Boiling point of H °C
EVAPORIZATION
-Takes place at the surface of the liquid.
VAPORIZATON: the change from a liquid to gas.
2 TYPES;
BOILING
EVAPORIZATION

13. BOILING
EVAPORATION

14. CONDENSATION -change from gas to liquid Formation of droplets
Water vapor in the atmosphere condenses to water droplets (rain).

15. 3.CHANGES BETWEEN SOLID AND GAS STATE
SUBLIMATION
-change from solid to gas without becoming liquid.
Ex. Dry ice (solid of C02)
DEPOSITION
-change from gas to solid

16. IN SUMMARY….