1. Chapter 12
Thermal Energy

2. 12.1- Temperature and Thermal Energy
Thermodynamics- the study of heat transformations into other forms of energy
began with 18th century steam engines

3. Thermal Energy Thermal Energy- total energy of a molecule
From this the average energy per molecule can be calculated

4. Hot Objects
What will happen to this balloon if it is placed in a refrigerator? What about over a pot of boiling water?

5. Solids
Particles cannot move freely- Vibrate

6. Thermal Energy and Temperature
Group 1

7. Energy DOES depend on mass
Temperature- depends on the average kinetic energy of particles; does not depend on mass
How much energy would a 2 kg block have to have compared to 1 kg block at the same temperature?
Energy DOES depend on mass
Average Kinetic Energy per particle= Total Kinetic Energy/ Number of Particle

8. Equilibrium and Thermometry
Conduction- transfer of kinetic energy when particles collide

9. Thermal Equilibrium
Thermal Equilibrium- the state in which the rate of energy flow between the two objects is equal and the objects are at the same temperature
Thermometers: GROUP 2

10. Temperature Scales Celsius- developed with water in mind
Kelvin- no negative temperatures
TC+273=TK
Temperature limits
No upper limit
Lower limit is absolute zero ( oC)

11. Heat and Flow of Thermal Energy
Heat- energy that is transferred between objects
Always flows from hot to cold
Conduction and Convection- GROUP 3
RADIATION- GROUP 4

12. Specific Heat
The amount the temperature increases depends on the mass and type of object.
The amount of energy that must be added to the material to raise the temperature of a unit mass by one temperature unit.
J/kg K
Table 12-1 page 318

13. Heat Transfer Q=mC∆T
Heat transfer is equal to the mass of an object times the specific heat of the object times the difference between the final and initial temperatures.

14. Math Examples

15. Calorimetry: Measuring Specific Heat
Calorimeter-device used to measure changes in thermal energy
Tf=mACATA + mBCBTB
mACA + mBCB

16. Math Practice

17. 12.2 Changes of State and the Laws of Thermodynamics
As the thermal energy of an object increases, the motion of the particles __________, and the temperature __________.

18. Melting Point Change from a solid to a liquid
All energy goes to break forces between particles.
No energy increase KE
Temperature ____________________.

19. Boiling Point Change from a liquid to a gas
Temperature ____________________.

20. Heat of Fusion Amount of energy needed to melt 1 kg of a substance
Q=mHf

21. Heat of Vaporization
Thermal energy needed to vaporize 1 kg of a liquid
Q=mHv

22. What would the equation be for the freezing of a substance?

23. Math Examples

24. You will have all day on Thursday to work on Book Work, the Laboratory Analysis, or the Chapter 12 Study Guide.
Friday we will finish Chapter 12 Notes
Monday we be doing another lab.
Tuesday we will grade the Study Guides
Test Wednesday

25. 1st Law of Thermodynamics Heat Engines Efficiency Refrigerators
Heat Pumps
2nd Law of Thermodynamics
Entropy
Violations of the 2nd Law