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THERMAL ENERGY
Vocabulary Review Write the term that correctly completes the statement. Use each term once. convection heat engine
second law of thermodynamics entropy heat of fusion
specific heat first law of thermodynamics heat of vaporization
thermal conduction heat radiation
thermal equilibrium 1. _________________________ ____ is the state at which the rate of thermal energy transfer between two objects is equal and the objects are at the same temperature. 2. _________________________ The transfer of thermal energy between objects is called ____ . 3. _________________________ The amount of energy required to raise the temperature of one unit mass of a substance by one temperature unit is the ____ of the substance. 4. _________________________ The amount of energy needed to melt 1 kg of a substance is the ____ . 5. _________________________ The ____ states that the change in thermal energy of an object equals the heat added to the object minus the work done by the object. 6. _________________________ ____ is the transfer of kinetic energy when particles collide. 7. _________________________ ____ is a measure of the energy dispersal of a system. 8. _________________________ A device that converts thermal energy to mechanical energy is a(n) ____ . 9. _________________________ The ____ states that natural processes go in a direction that increases the total entropy of the universe. 10. _________________________ ____ is the motion of a fluid caused by temperature differences. 11. _________________________ The amount of energy required to convert 1 kg of a substance from a liquid to a gas is the ____ . 12. _________________________ The transfer of energy by electromagnetic waves is called ____ . Chapter 12  Thermal Energy
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SECTION 1 Temperature, Heat, and Thermal Energy
In your textbook, read about the theory of thermal energy and temperature. For each statement below, write true or rewrite the italicized part to make the statement true. 1. _________________________ The temperature of an object is a measure of the total kinetic energy of the particles. 2. _________________________ The thermal energy in an object depends on the number of particles in the object and the temperature of the object. 3. _________________________ Two bodies are in rotational equilibrium if they are at the same temperature. 4. _________________________ A Kelvin is equal in magnitude to a Celsius degree. 5. _________________________ Absolute zero is equal to 0°C. 6. _________________________ The freezing point of water is 0°C or 212 K. 7. _________________________ Absolute zero is the point at which a substance has minimal thermal energy. In your textbook, read about specific heat. For each term on the left, write the letter of the corresponding item. 8. _____ unit of specific heat a. K 9. _____ heat b. S 10. _____ degree Celsius c. T 11. _____ Kelvin d. C 12. _____ entropy e. Q 13. _____ energy change f. J/(kg•K) 14. _____ temperature change g. E Answer the following questions. Use complete sentences. 15. Why is the Kelvin temperature scale rather than the Celsius temperature scale used in science? Use “kinetic energy” in your answer. ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Chapter 12  Thermal Energy
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16. The diagram shows the construction of the inner liner of a vacuum bottle. How does a vacuum bottle prevent the transfer of thermal energy: a.
by conduction? __________________________________________ __________________________________________ b.
by convection? __________________________________________ __________________________________________ __________________________________________ c.
by radiation? _________________________________________________________________________ _________________________________________________________________________ 17. What is the specific heat of a metal if it takes 15,000 J of heat to raise the temperature of a 620‐g sample from 15.0C to 85.0C? In your textbook, read about calorimetry. Use the following information to answer questions 18–21. A student uses a foam cup as a calorimeter. The student places 100.0 g of water at 20C in the cup. The student adds 100.0 g of lead shot at 120C to the cup. The water and shot are then allowed to reach thermal equilibrium. The specific heat of lead is 130 J/(kg•K). 18. Is Q for the water positive or negative? ____________________________________________________________________________________ 19. Is Q for the lead shot positive or negative? ____________________________________________________________________________________ 20. Assuming that no thermal energy is lost to the surroundings, how does the total energy of the system compare with the total energy of the water and lead before mixing? ____________________________________________________________________________________ 21. What is the final temperature of the water at thermal equilibrium? ____________________________________________________________________________________ Chapter 12  Thermal Energy
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