Chapter 9 Defining Temperature Section 1 Temperature and Thermal Equilibrium Chapter 9 Defining Temperature Temperature - measure of the average kinetic energy of the particles in a substance. Adding or removing energy usually changes temperature. Internal energy - energy of a substance due to both the random motions of its particles and to the potential energy that results from the distances and alignments between the particles.

Forms of Internal Energy Section 1 Temperature and Thermal Equilibrium Chapter 9 Forms of Internal Energy

Section 1 Temperature and Thermal Equilibrium Chapter 9 Thermal equilibrium - state in which two bodies in physical contact with each other have identical temperatures. The temperature of any two objects in thermal equilibrium always lies between their initial temperatures.

Chapter 9 Thermal Equilibrium Section 1 Temperature and Thermal Equilibrium Chapter 9 Thermal Equilibrium

Chapter 9 Thermal Expansion Section 1 Temperature and Thermal Equilibrium Chapter 9 Thermal Expansion Thermal expansion - if the temperature of a substance increases, so does its volume Coefficient of volume expansion - thermal expansion characteristics of a material Gases have the largest values for this coefficient. Solids typically have the smallest values.

Chapter 9 Thermal Expansion Section 1 Temperature and Thermal Equilibrium Chapter 9 Thermal Expansion

Measuring Temperature Section 1 Temperature and Thermal Equilibrium Chapter 9 Measuring Temperature Ice point or melting point of water is defined as zero degrees Celsius, or 0°C. Steam point or boiling point of water is defined as 100°C.

Section 1 Temperature and Thermal Equilibrium Chapter 9 The number 32.0 indicates the difference between the ice point value in each scale: 0.0ºC and 32.0ºF.

Chapter 9 Kelvin scale - temperature scale with only positive values Section 1 Temperature and Thermal Equilibrium Chapter 9 Kelvin scale - temperature scale with only positive values Because the kinetic energy of the atoms in a substance must be positive, the absolute temperature that is proportional to that energy should be positive also.

Chapter 9 Section 1 Temperature and Thermal Equilibrium The graph suggests that if the temperature could be lowered to –273.15°C, the pressure would be zero. This temperature is designated in the Kelvin scale as 0.00 K, where K represents the temperature unit called the kelvin. Temperatures in the Kelvin scale are indicated by the symbol T.

Section 1 Temperature and Thermal Equilibrium Chapter 9 A temperature difference of one degree is the same on the Celsius and Kelvin scales. The two scales differ only in the choice of zero point. Thus, the ice point (0.00°C) equals 273.15 K, and the steam point (100.00°C) equals 373.15 K. The Celsius temperature can therefore be converted to the Kelvin temperature by adding 273.15:

Temperature Scales and Their Uses Section 1 Temperature and Thermal Equilibrium Chapter 9 Temperature Scales and Their Uses

Chapter 9 Heat and Energy Section 2 Defining Heat Chapter 9 Heat and Energy Heat - energy transferred between objects because of a difference in their temperatures. Energy transferred as heat tends to move from an object at higher temperature to an object at lower temperature. Heat is indicated by the symbol Q. Joule - SI unit for energy.

Transfer of Particles’ Kinetic Energy as Heat Section 2 Defining Heat Chapter 9 Transfer of Particles’ Kinetic Energy as Heat Energy is transferred as heat from the higher-energy particles to the lower-energy particles, as shown on the left. The net energy transferred is zero when thermal equilibrium is reached, as shown on the right.

Section 2 Defining Heat Chapter 9 Temperature and Heat

Thermal Units and Their Values in Joules Section 2 Defining Heat Chapter 9 Thermal Units and Their Values in Joules

Chapter 9 Thermal Conduction Section 2 Defining Heat Chapter 9 Thermal Conduction The type of energy transfer that is due to atoms transferring vibrations to neighboring atoms is called thermal conduction. The rate of thermal conduction depends on the substance. Two other mechanisms for transferring energy as heat are convection and electromagnetic radiation. When this burner is turned on, the skillet’s handle heats up because of conduction.

Convection, Conduction, and Radiation Section 2 Defining Heat Chapter 9 Convection, Conduction, and Radiation

Conservation of Energy Section 2 Defining Heat Chapter 9 Conservation of Energy The sum of the changes in potential, kinetic, and internal energy is equal to zero. CONSERVATION OF ENERGY DPE + DKE + DU = 0 the change in potential energy + the change in kinetic energy + the change in internal energy = 0

Conservation of Energy Section 2 Defining Heat Chapter 9 Conservation of Energy

Section 3 Changes in Temperature and Phase Chapter 9 Specific heat capacity - the energy required to change the temperature of 1 kg of that substance by 1°C. Every substance has a unique specific heat capacity.

Specific Heat Capacities Section 3 Changes in Temperature and Phase Chapter 9 Specific Heat Capacities

Section 3 Changes in Temperature and Phase Chapter 9 Calorimetry Calorimetry is used to determine specific heat capacity. Calorimetry is an experimental procedure used to measure the energy transferred from one substance to another as heat. A simple calorimeter allows the specific heat capacity of a substance to be determined.

Section 3 Changes in Temperature and Phase Chapter 9 Calorimetry

energy absorbed by water = energy released by substance Section 3 Changes in Temperature and Phase Chapter 9 Calorimetry Because the specific heat capacity of water is well known (cp,w= 4.186 kJ/kg•°C), the energy transferred as heat between an object of unknown specific heat capacity and a known quantity of water can be measured. energy absorbed by water = energy released by substance Qw = –Qx cp,wmw∆Tw = –cp,xmx∆Tx

Chapter 9 Sample Problem Calorimetry Section 3 Changes in Temperature and Phase Chapter 9 Sample Problem Calorimetry A 0.050 kg metal bolt is heated to an unknown initial temperature. It is then dropped into a calorimeter containing 0.15 kg of water with an initial temperature of 21.0°C. The bolt and the water then reach a final temperature of 25.0°C. If the metal has a specific heat capacity of 899 J/kg•°C, find the initial temperature of the metal.

Chapter 9 Sample Problem 1. Define Section 3 Changes in Temperature and Phase Chapter 9 Sample Problem 1. Define Given: mm = 0.050 kg cp,m = 899 J/kg•°C mw = 0.15 kg cp,w = 4186 J/kg•°C Tw = 21.0°C Tf = 25.0°C Unknown: Tm = ? Diagram:

Section 3 Changes in Temperature and Phase Chapter 9 Latent Heat When substances melt, freeze, boil, condense, or sublime, the energy added or removed changes the internal energy of the substance without changing the substance’s temperature. These changes in matter are called phase changes. The energy per unit mass that is added or removed during a phase change is called latent heat, abbreviated as L. Q = mL energy transferred as heat during phase change = mass  latent heat

Section 3 Changes in Temperature and Phase Chapter 9 Latent Heat

Section 3 Changes in Temperature and Phase Chapter 9 Latent Heat Heat of fusion (Lf ) - during melting, energy that is added to a substance equals the difference between the total potential energies for particles in the solid and the liquid phases. Heat of vaporization (Lv) - during vaporization, energy that is added to a substance equals the difference in the potential energy of attraction between the liquid particles and between the gas particles.

Chapter 9 Multiple Choice Standardized Test Prep Multiple Choice 1. What must be true about two given objects for energy to be transferred as heat between them? A. The objects must be large. B. The objects must be hot. C. The objects must contain a large amount of energy. D. The objects must have different temperatures.

Chapter 9 Multiple Choice Standardized Test Prep Multiple Choice 1. What must be true about two given objects for energy to be transferred as heat between them? A. The objects must be large. B. The objects must be hot. C. The objects must contain a large amount of energy. D. The objects must have different temperatures.

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued 2. A metal spoon is placed in one of two identical cups of hot coffee. Why does the cup with the spoon have a lower temperature after a few minutes? F. Energy is removed from the coffee mostly by conduction through the spoon. G. Energy is removed from the coffee mostly by convection through the spoon. H. Energy is removed from the coffee mostly by radiation through the spoon. J. The metal in the spoon has an extremely large specific heat capacity.

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued 2. A metal spoon is placed in one of two identical cups of hot coffee. Why does the cup with the spoon have a lower temperature after a few minutes? F. Energy is removed from the coffee mostly by conduction through the spoon. G. Energy is removed from the coffee mostly by convection through the spoon. H. Energy is removed from the coffee mostly by radiation through the spoon. J. The metal in the spoon has an extremely large specific heat capacity.

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the passage below to answer questions 3–4. The boiling point of liquid hydrogen is –252.87°C. 3. What is the value of this temperature on the Fahrenheit scale? A. 20.28°F B. –220.87°F C. –423.2°F D. 0°F

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the passage below to answer questions 3–4. The boiling point of liquid hydrogen is –252.87°C. 3. What is the value of this temperature on the Fahrenheit scale? A. 20.28°F B. –220.87°F C. –423.2°F D. 0°F

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the passage below to answer questions 3–4. The boiling point of liquid hydrogen is –252.87°C. 4. What is the value of this temperature in kelvins? F. 273 K G. 20.28 K H. –423.2 K J. 0 K

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the passage below to answer questions 3–4. The boiling point of liquid hydrogen is –252.87°C. 4. What is the value of this temperature in kelvins? F. 273 K G. 20.28 K H. –423.2 K J. 0 K

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued 5. A cup of hot chocolate with a temperature of 40°C is placed inside a refrigerator at 5°C. An identical cup of hot chocolate at 90°C is placed on a table in a room at 25°C. A third identical cup of hot chocolate at 80°C is placed on an outdoor table, where the surrounding air has a temperature of 0°C. For which of the three cups has the most energy been transferred as heat when equilibrium has been reached? A. The first cup has the largest energy transfer. B. The second cup has the largest energy transfer. C. The third cup has the largest energy transfer. D. The same amount of energy is transferred as heat for all three cups.

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued 5. A cup of hot chocolate with a temperature of 40°C is placed inside a refrigerator at 5°C. An identical cup of hot chocolate at 90°C is placed on a table in a room at 25°C. A third identical cup of hot chocolate at 80°C is placed on an outdoor table, where the surrounding air has a temperature of 0°C. For which of the three cups has the most energy been transferred as heat when equilibrium has been reached? A. The first cup has the largest energy transfer. B. The second cup has the largest energy transfer. C. The third cup has the largest energy transfer. D. The same amount of energy is transferred as heat for all three cups.

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued 6. What data are required in order to determine the specific heat capacity of an unknown substance by means of calorimetry? F. cp,water, Twater, Tsubstance, Tfinal, Vwater, Vsubstance G. cp,substance, Twater, Tsubstance, Tfinal, mwater, msubstance H. cp,water, Tsubstance, mwater, msubstance J. cp,water, Twater, Tsubstance, Tfinal, mwater, msubstance

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued 6. What data are required in order to determine the specific heat capacity of an unknown substance by means of calorimetry? F. cp,water, Twater, Tsubstance, Tfinal, Vwater, Vsubstance G. cp,substance, Twater, Tsubstance, Tfinal, mwater, msubstance H. cp,water, Tsubstance, mwater, msubstance J. cp,water, Twater, Tsubstance, Tfinal, mwater, msubstance

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued 7. During a cold spell, Florida orange growers often spray a mist of water over their trees during the night. Why is this done? A. The large latent heat of vaporization for water keeps the trees from freezing. B. The large latent heat of fusion for water prevents it and thus the trees from freezing. C. The small latent heat of fusion for water prevents the water and thus the trees from freezing. D. The small heat capacity of water makes the water a good insulator.

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued 7. During a cold spell, Florida orange growers often spray a mist of water over their trees during the night. Why is this done? A. The large latent heat of vaporization for water keeps the trees from freezing. B. The large latent heat of fusion for water prevents it and thus the trees from freezing. C. The small latent heat of fusion for water prevents the water and thus the trees from freezing. D. The small heat capacity of water makes the water a good insulator.

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the heating curve to answer questions 8–10. The graph shows the change in temperature of a 23 g sample as energy is added to the sample as heat. 8. What is the specific heat capacity of the liquid? F. 4.4  105 J/kg•°C G. 4.0  102 J/kg•°C H. 5.0  102 J/kg•°C J. 1.1  103 J/kg•°C

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the heating curve to answer questions 8–10. The graph shows the change in temperature of a 23 g sample as energy is added to the sample as heat. 8. What is the specific heat capacity of the liquid? F. 4.4  105 J/kg•°C G. 4.0  102 J/kg•°C H. 5.0  102 J/kg•°C J. 1.1  103 J/kg•°C

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the heating curve to answer questions 8–10. The graph shows the change in temperature of a 23 g sample as energy is added to the sample as heat. 9. What is the latent heat of fusion? A. 4.4  105 J/kg B. 4.0  102 J/kg•°C C. 10.15  103 J D. 3.6  107 J/kg

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the heating curve to answer questions 8–10. The graph shows the change in temperature of a 23 g sample as energy is added to the sample as heat. 9. What is the latent heat of fusion? A. 4.4  105 J/kg B. 4.0  102 J/kg•°C C. 10.15  103 J D. 3.6  107 J/kg

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the heating curve to answer questions 8–10. The graph shows the change in temperature of a 23 g sample as energy is added to the sample as heat. 10. What is the specific heat capacity of the solid? F. 1.85  103 J/kg•°C G. 4.0  102 J/kg•°C H. 5.0  102 J/kg•°C J. 1.1  103 J/kg•°C

Multiple Choice, continued Chapter 9 Standardized Test Prep Multiple Choice, continued Use the heating curve to answer questions 8–10. The graph shows the change in temperature of a 23 g sample as energy is added to the sample as heat. 10. What is the specific heat capacity of the solid? F. 1.85  103 J/kg•°C G. 4.0  102 J/kg•°C H. 5.0  102 J/kg•°C J. 1.1  103 J/kg•°C

Chapter 9 Short Response Standardized Test Prep Short Response Base your answers to questions 11–12 on the information below. The largest of the Great Lakes, Lake Superior, contains 1.20  1016 kg of fresh water, which has a specific heat capacity of 4186 J/kg•°C and a latent heat of fusion of 3.33  105 J/kg. 11. How much energy would be needed to increase the temperature of Lake Superior by 1.0°C?

Chapter 9 Short Response Standardized Test Prep Short Response Base your answers to questions 11–12 on the information below. The largest of the Great Lakes, Lake Superior, contains 1.20  1016 kg of fresh water, which has a specific heat capacity of 4186 J/kg•°C and a latent heat of fusion of 3.33  105 J/kg. 11. How much energy would be needed to increase the temperature of Lake Superior by 1.0°C? Answer: 5.0  1019 J

Short Response, continued Chapter 9 Standardized Test Prep Short Response, continued Base your answers to questions 11–12 on the information below. The largest of the Great Lakes, Lake Superior, contains 1.20  1016 kg of fresh water, which has a specific heat capacity of 4186 J/kg•°C and a latent heat of fusion of 3.33  105 J/kg. 12. If Lake Superior were still liquid at 0°C, how much energy would need to be removed from the lake for it to become completely frozen?

Short Response, continued Chapter 9 Standardized Test Prep Short Response, continued Base your answers to questions 11–12 on the information below. The largest of the Great Lakes, Lake Superior, contains 1.20  1016 kg of fresh water, which has a specific heat capacity of 4186 J/kg•°C and a latent heat of fusion of 3.33  105 J/kg. 12. If Lake Superior were still liquid at 0°C, how much energy would need to be removed from the lake for it to become completely frozen? Answer: 5.00  1021 J

Short Response, continued Chapter 9 Standardized Test Prep Short Response, continued 13. Ethyl alcohol has about one-half the specific heat capacity of water. If equal masses of alcohol and water in separate beakers at the same temperature are supplied with the same amount of energy, which will have the higher final temperature?

Short Response, continued Chapter 9 Standardized Test Prep Short Response, continued 13. Ethyl alcohol has about one-half the specific heat capacity of water. If equal masses of alcohol and water in separate beakers at the same temperature are supplied with the same amount of energy, which will have the higher final temperature? Answer: the ethyl alcohol

Short Response, continued Chapter 9 Standardized Test Prep Short Response, continued 14. A 0.200 kg glass holds 0.300 kg of hot water, as shown in the figure. The glass and water are set on a table to cool. After the temperature has decreased by 2.0°C, how much energy has been removed from the water and glass? (The specific heat capacity of glass is 837 J/kg•°C, and that of water is 4186 J/kg•°C.)

Short Response, continued Chapter 9 Standardized Test Prep Short Response, continued 14. A 0.200 kg glass holds 0.300 kg of hot water, as shown in the figure. The glass and water are set on a table to cool. After the temperature has decreased by 2.0°C, how much energy has been removed from the water and glass? (The specific heat capacity of glass is 837 J/kg•°C, and that of water is 4186 J/kg•°C.) Answer: 2900 J

Chapter 9 Extended Response Standardized Test Prep Extended Response 15. How is thermal energy transferred by the process of convection?

Chapter 9 Extended Response Standardized Test Prep Extended Response 15. How is thermal energy transferred by the process of convection? Answer: The increasing temperature of a liquid or gas causes it to become less dense, so it rises above colder liquid or gas, transferring thermal energy with it.

Extended Response, continued Chapter 9 Standardized Test Prep Extended Response, continued 16. Show that the temperature –40.0° is unique in that it has the same numerical value on the Celsius and Fahrenheit scales. Show all of your work.

Extended Response, continued Chapter 9 Standardized Test Prep Extended Response, continued 16. Show that the temperature –40.0° is unique in that it has the same numerical value on the Celsius and Fahrenheit scales. Show all of your work. Answer:

Measuring Temperature Section 1 Temperature and Thermal Equilibrium Chapter 9 Measuring Temperature

Determining Absolute Zero for an Ideal Gas Section 1 Temperature and Thermal Equilibrium Chapter 9 Determining Absolute Zero for an Ideal Gas

Section 3 Changes in Temperature and Phase Chapter 9 Calorimetry