1. A 50. 0 g ball is dropped from an altitude of 2. 0 km
A 50.0 g ball is dropped from an altitude of 2.0 km. Calculate: Ui, Kmax, & W done through the fall

2. Chapter 12
Thermal Energy

3. Thermodynamics
The movement of heat

4. Kinetic Theory All matter is made up of tiny particles
All particles are in constant motion
All collisions are elastic

5. A measure of average kinetic energy
Temperature
A measure of average kinetic energy

6. A measure of heat intensity
Temperature
A measure of heat intensity

7. Thermal Equilibrium
When the average kinetic energy of two or more substances become equal; thus their particles have the same exchange rate

8. Because it is a measure of average kinetic energy, temperature is related to the motion of particles (atoms, molecules, ions, etc)

9. Thermometer
A device, calibrated to some temp scale, that is allowed to come to thermal equilibrium with something else

10. Temperature Scales Celsius (oC) Kelvin (K) Based on MP & BP of water
Based of absolute temperature

11. Temperature Scales
K = oC

12. Convert Temperatures
100 K = ___ oC
100 oC = ___ K

13. A form of energy that flows due to temperature differences
Heat
A form of energy that flows due to temperature differences

14. Heat (Q)
Because particles at higher temp. move faster than particles at a lower temp., the net flow of heat is Hot to Cold

15. Heat (Q)
Heat will continue to have net flow from H  C as long as there is a temperature difference

16. Heat (Q)
When there is no temperature differences, the system has reached thermal equilibrium

17. The movement of energy by means other than temperature difference
Work
The movement of energy by means other than temperature difference

18. 1st Law of Thermo.
The increase in thermal energy = sum of heat added & work done to a system

19. 1st Law of Thermo.
DE = Q + W

20. In Most Engines Heat is added by some high energy source (gas)
Work is done by the engine

21. In Most Engines
DE = Q + W
But W < 0

22. A measure of the disorder in a system
Entropy
A measure of the disorder in a system

23. In natural processes, entropy increases
2nd Law of Thermo.
In natural processes, entropy increases

24. When fuel is burned, entropy is increased

25. The thermal energy required to raise 1 unit mass of matter 1 degree
Specific Heat (C)
The thermal energy required to raise 1 unit mass of matter 1 degree

26. The thermal energy required to raise 1 kg of matter 1 degree K
Specific Heat (C)
The thermal energy required to raise 1 kg of matter 1 degree K

27. Heat transfer = mass x specific heat x the temperature change
Heat (Q or DH)
Heat transfer = mass x specific heat x the temperature change
Q = mCDT

28. Calculate the heat required to raise 50. 0 g of water from 25
Calculate the heat required to raise 50.0 g of water from 25.0oC to 65.0oC. Cwater = 4180 J/kgK

29. Calculate the heat required to raise 250.0 g of lead from
-25.0oC to 175.0oC. Clead = 130 J/kgK

30. 28 kJ of heat was required to raise the temperature of 100
28 kJ of heat was required to raise the temperature of g of a substance from -125oC to 575oC. Calculate: C

31. 3. 6 kJ of heat was required to raise the temperature of 10
3.6 kJ of heat was required to raise the temperature of 10.0 g of a substance from -22oC to 578oC. Calculate: C

32. The total energy of an isolated system is constant
Conservation of Heat
The total energy of an isolated system is constant

33. Because the total amount of heat is constant
Conservation of Heat
Because the total amount of heat is constant
q or DHsystem = 0

34. Conservation of Heat
q or DHsystem = 0
DHsys = DH1 + DH2 + ..
qsys = q1 + Dq2 + ..= 0

35. qsys = q1 + Dq2 = 0 Conservation of Heat mCDT1 + mCDT2 = 0

36. qsys = qgained + qlost qgained = - qlost Conservation of Heat
mCDTgain = - mCDTlost

37. A 50.0 g slug of metal at 77.0 oC is added to 500. g water at 25.0oC.
Teq= 27.0oC.
Calculate: Cmetal
Cwater = 4180 J/kgK

38. A 200.0 g slug of metal at 77.5 oC is added to 400. g water at 25.0oC.
Teq= 27.5oC.
Calculate: Cmetal
Cwater = 4180 J/kgK

39. Solving Mixture Temperatures
qsystem = 0
qsystem = qhot + qcold
mCDThot = -mCDTcold
DT = Tf – Ti
mC(Tf – Ti)hot = -mC(Tf – Ti)cold

40. Conservation of Heat
mChTf - mChTh
+mCcTf - mCcTc
= 0

41. Conservation of Heat
mChTf - mChTh =
-mCcTf + mCcTc

42. 20. 0 g of water at 25. 0oC is added to 30. 0 g water at 75. 0oC
20.0 g of water at 25.0oC is added to g water at 75.0oC. Calculate: Teq Cwater = 4180 J/kgK

43. 500. g of water at 75. 0oC is added to 300. g water in a 200
500. g of water at 75.0oC is added to g water in a 200. g calorimeter all at 25.0oC. Calculate: Teq Cwater = 4180 J/kgK
Ccal = 1000 J/kgK

44. A 500. 0 g slug of metal at 87. 5. oC is added to 4. 0 kg water in a 1
A g slug of metal at 87.5.oC is added to 4.0 kg water in a 1.0 kg can at 25.0oC. Teq= 27.5oC.
Calculate: Cmetal
Cwater = 4180 J/kgK
Ccan = 1.0 J/gK

45. States of Matter
Solid
Liquid
Gas

46. Solid Has definite size & definite shape
Particles vibrate at fixed positions

47. Liquid Has definite size but no definite shape
Particles vibrate at moving positions

48. Gas
Has neither size nor shape
Particles move at random

49. When a substance changes from one state of matter to another
Change of State
When a substance changes from one state of matter to another

50. Change of state involves an energy change

51. Changes of State Melting-Freezing Boiling-Condensation
Sublimation-Deposition

52. Melting Point
The temperature at which a solid is at dynamic equilibrium with its liquid.
Freezing Point (Same)

53. Boiling Point
The temperature at which a liquid is at dynamic equilibrium with its gas.
Condensation Point (Same)

54. Changes of State
During changes of state, the temperature remains constant; all energy is used to change the state

55. Heat of Fusion (Hf)
The heat required to melt one unit mass of a substance at its MP

56. Heat of Fusion (Hf)
Hf water = 3.34 x 105 J/kg
Hf water = 334 J/g

57. Heat of Vaporization (HV)
The heat required to vaporize one unit mass of a substance at its BP

58. Heat of Vaporization (HV)
Hv water = 2.26 x 106 J/kg
Hv water = 2260 J/g

60. Change of State
q = mH

61. Changes of State
qf = mHf
qv = mHv

62. Calculate the heat required to change 250 g ice to water at its MP: Hf = 3.34 x 105 J/kg

63. Calculate the heat required to boil 400 g of water at its BP: HV = 2
Calculate the heat required to boil 400 g of water at its BP: HV = 2.26 x 106 J/kg

64. Calculate the heat change when the temperature of 2
Calculate the heat change when the temperature of 2.0 kg H2O is changed from 50oC to 150oC:

65. Calculate the heat change when the temperature of 4
Calculate the heat change when the temperature of 4.0 kg H2O is changed from
-25.0oC to 125.0oC:

66. Constants for Water Hf = 3.34 x 105 J/kg Hv = 2.26 x 106 J/kg
Cice = J/kgK
Cwater = 4180 J/kgK
Csteam = 2020 J/kgK

67. Total DE equal work done plus heat added to it
1st Law of Thermo
Total DE equal work done plus heat added to it
DE = Q + W

68. Heat Engine
Any engine that converts heat energy to mechanical energy (Steam, internal combustion, etc.)

69. Heat Pumps & Refrigerators
Use pressure changes & the heat of vaporization to transfer heat from cold to hot

70. The total entropy of an isolated system always increases
2nd Law of Thermo
The total entropy of an isolated system always increases

71. 20. 0 g of lead at 75. 0oC is added to 100. 0 g water at 25. 0oC
20.0 g of lead at 75.0oC is added to g water at 25.0oC. Calculate: Teq Cwater = 4180 J/kgK
Clead = 130. J/kgK

72. 50. 0 g of milk at 5. 00oC is added to 500. 0 g coffee in a 400
50.0 g of milk at 5.00oC is added to g coffee in a g cup at 75.0oC. Calculate: Teq Ccoffee = 4.00 J/gK
Ccup = 1.50 J/gK
Cmilk = 3.50 J/gK

73. Ti = 25.0oC Tf = 200.0oC BP = 100.0oC MP = 0.0oC Mass of H2O = 5.00 kg
Calculate: Qtotal
Cice= 2.06 J/gK, Hv = 2260 J/g
Cwater= 4.18 J/gK, Hf = 334 J/g
Csteam= 2.02 J/gK

74. Ti = -50.0oC Tf = 300.0oC BP = 100.0oC MP = 0.0oC
Mass of H2O = 5.00 kg
Calculate: Qtotal
Cice= 2.06 J/gK, Hv = 2260 J/g
Cwater= 4.18 J/gK, Hf = 334 J/g
Csteam= 2.02 J/gK

75. 20. 0 g of lead at 75. 0oC is added to 100. 0 g water at 25. 0oC
20.0 g of lead at 75.0oC is added to g water at 25.0oC. Calculate: Teq Cwater = 4180 J/kgK
Clead = 130. J/kgK

76. A 500. 0 g slug of metal at 86. 5. oC is added to 4. 0 kg water in a 2
A g slug of metal at 86.5.oC is added to 4.0 kg water in a 2.0 kg can at 24.0oC. Teq= 26.5oC.
Calculate: Cmetal
Cwater = 4180 J/kgK
Ccan = 1.0 J/gK

77. A 50. 0 g of ice at -20. 0 oC is added to 2. 0 kg water in a 1
A 50.0 g of ice at oC is added to 2.0 kg water in a 1.0 kg can at 25.0oC. Calculate: Teq
Cw = 4180 J/kgK Cc = 1.0 J/gK
Cice = 2.06 J/gK Hf = 340 J/g

78. A 50. 0 g of steam at 120. 0 oC is added to 2. 0 kg water in a 1
A 50.0 g of steam at oC is added to 2.0 kg water in a 1.0 kg can at 20.0oC. Calculate: Teq
Cw = 4180 J/kgK
Cc = 1.0 J/gK
HV = 2260 J/g

79. Constants will be on the board
A g of steam at oC is added to 2.0 kg ice in a 1.0 kg can at
-20.0oC. Calculate: Teq
Constants will be on the board