1 Outline Chapter 5 Matter and Energy 5-9. Molecular Motion and Temperature 5-10. Liquids and Solids 5-11. Evaporation and Boiling 5-12. Melting 5-13. Heat Engines 5-14. Thermodynamics 5-15. Fate of the Universe 5-16. Entropy 5-1. Temperature 5-2. Heat 5-3. Metabolic Energy 5-4. Density 5-5. Pressure 5-6. Buoyancy 5-7. Gas Laws 5-8. Kinetic Theory of Gases 5-1. Temperature Temperature = average kinetic energy. Heat= total energy. The Lake and the glass of water both are at 70 o F. Which has the most heat? 5-1. Temperature
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Outline Chapter 5 Matter and
Energy
5-9. Molecular Motion and
Temperature
5-10. Liquids and Solids
5-11. Evaporation and Boiling
5-12. Melting
5-13. Heat Engines
5-14. Thermodynamics
5-15. Fate of the Universe
5-16. Entropy
5-1. Temperature
5-2. Heat
5-3. Metabolic Energy
5-4. Density
5-5. Pressure
5-6. Buoyancy
5-7. Gas Laws
5-8. Kinetic Theory of
Gases
5-1. Temperature
Temperature = average kinetic energy.
Heat= total energy.
The Lake and the glass of water both are at
70oF. Which has the most heat?
5-1. Temperature
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5-1. Temperature
The fahrenheit scale in which water freezes at 32°F and boils at 212°F at sea level.The celsius scale in which water freezes at 0°C and boils at 100°C at sea level.
between the molecules of a liquid are stronger than those in a gas but
weaker than those in a solid.
Molecules of a solid do not move freely about but vibrate around fixed
positions.
5-9. Molecular Motion and
Temperature•The absolute temperature of a gas is
proportional to the average kinetic energy of its molecules.
•Gas molecules, even at 0 K (-273° C),
would still possess a small amount of kinetic
energy.
•Compression of a gas increases its
temperature; expansion decreases its
temperature.
•Gas molecules are in constant motion
because their collisions result in no net loss of energy.
Increases decreases
5-11. Evaporation and Boiling
Boiling is when vapor pressure equals atmospheric pressure.
Sublimation is the direct conversion of a substance from the solid to the vapor state, or from the vapor state to the solid state, without it entering the liquid state.
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5-11. Evaporation and Boiling
• As liquid is heated, bubbles of gas begin to form
These bubbles can only form when the gas
inside has enough pressure to overcome the
pressure in the liquid and atmosphere
above the liquid
As the gas inside the bubbles expands, the
buoyant force on the bubble grows,
eventually causing it to rise to the surface
FB
Changes of State
heat of vaporization
heat of fusion
Changes of State
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5-13. Heat Engines
5-13. Heat Engines
http://auto.howstuffworks.com/engine1.htm
How a Refrigerator Works
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5-14. Thermodynamics
•Thermodynamics is the science of heat transformation.
•The first law of thermodynamics states: Energy cannot be created or destroyed, but it can be converted from one form to another.
•The second law of thermodynamics states: It is impossible to take heat from a source and change all of it to mechanical energy or work; some heat must be wasted.
Heat Engine Efficiency
Maximum efficiency of a heat engine depends on the
temperatures at which it takes in and ejects heat; the greater the ratio between the two temperatures, the more efficient the
Entropy is disorder. The universe is increasing its disorder (another version of the 2nd law of thermodynamics).
The heat death of the universe will occur when all particles of matter ultimately have the same average kinetic energy and exist in a state of maximum disorder.
Lecture Quiz 5
1. What do heat engines need to work?
2. What is the difference between heat and temperature?
3. What is room temperature in Centigrade?
4. What are the equations for density and pressure?
5. What is Entropy?
http://jersey.uoregon.edu/vlab/Cannon/
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Lecture Quiz 5
1. What do heat engines need to work? Hot and cold reservoir
2. What is the difference between heat and temperature? T=average KE, H=total energy
3. What is room temperature in Centigrade? 20oC
4. What are the equations for density and pressure? D=M/V P=F/A
5. What is Entropy? Disorder
Lecture Quiz 5
1. What do heat engines need to work?
2. What happens to the temperature of a material while it is melting?
3. What is the maximum efficiency of an engine when the temperature of the fluid in the radiator is 375K and the temperature of the exhaust gases is 750K?
4. What are the two laws of thermodynamics?
5. What is Entropy?
Lecture Quiz 5
1. What do heat engines need to work?Hot and cold reservoir
2. What happens to the temperature of a material while it is melting?It stays the same. Energy goes into phase change.
3. What is the maximum efficiency of an engine when the temperature of the fluid in the radiator is 375K and the temperature of the exhaust gases is 750K?Efficiency = 1- Tcold/Thot = 1-(375K/750k) = 0.50 = 50%
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Lecture Quiz 5
4. What are the two laws of thermodynamics?1-Energy cannot be created or destroyed, but it can be
converted from one form to another.
2-It is impossible to take heat from a source and change all of
it to mechanical energy or work; some heat must be wasted or