Section 1 review
In everyday life we might use the words temperature and heat interchangeably. In physics, however, they are different concepts. Temperature measures the average kinetic energy in random thermal motion per atom or molecule. Temperature is measured on the Celsius, Fahrenheit, and Kelvin scales. Both Celsius and Fahrenheit are based on the phase changes of water but the Kelvin scale is based on absolute zero. Matter takes different phases (solid, liquid, or gas) depending on its temperature. Heat, or thermal energy, is the total energy in random thermal motion for a whole collection of atoms or molecules. The strength of intermolecular bonds varies among materials. For this reason, equal amounts of different substances usually contain different amounts of heat even at the same temperature. The specific heat is the thermal energy (or heat) per unit mass for a substance, per degree Celsius. Read the text aloud
temperature, Brownian motion, thermometer, Celsius scale, Fahrenheit scale, absolute zero, Kelvin scale, Avogadro’s number, mole, kinetic theory, Boltzmann’s constant, phases of matter, gas, liquid, solid, heat, thermal energy, calorie, Calorie, specific heat

T C = 5 9 ( T F 32 )
T F = 9 5 T C +32
T K = T C +273.15
N A =6.022× 10 23
E= 3 2 k B T
Q=m c p ( T 2 T 1 ) =m c p ΔT

Review problems and questions

  1. An Italian exchange student living in the United States wants to set his apartment’s thermostat to 20°C. At what temperature in degrees Fahrenheit should he set the thermostat? Read the text aloud Show
  1. An American tourist in Paris, Goldie Locks, set her hotel room thermostat to 68°—not realizing that the thermostat works in degrees Celsius instead of degrees Fahrenheit.
    1. In an hour or two, will her hotel room feel hot, cold, or just right?
    2. At what temperature (in degrees Fahrenheit) did she set the thermostat?
    3. Would you expect there to be some property of the thermostat that would prevent her from setting it at 68°? Explain. Read the text aloud Show
  1. A racing cyclist burns 1,260 Calories in an hour, which go into powering his bicycle.
    1. How many joules does he burn in an hour?
    2. How many watts of power does he generate?
    3. How many incandescent light bulbs rated at 100 W could he theoretically power with this energy?
    4. How many fluorescent bulbs rated at 100 W could he power? Read the text aloud Show
  1. Three 30 g metal balls, one each of aluminum, copper, and lead, are placed into a large beaker of hot water for a few minutes. [The specific heats of aluminum, copper, and lead are 903, 385, and 130 J/(kg °C), respectively.]
    1. Which, if any, of the balls will reach the highest temperature? Explain.
    2. Which, if any, of the balls will have the most thermal energy? Explain. Read the text aloud Show
  1. What is the energy of a mole of carbon atoms at a room temperature of 20°C? Read the text aloud Show
  1. Which of the following should you do if a mercury thermometer breaks in the classroom?
    1. Tell your teacher about it at the end of the class period so that she can clean up the spill before the next class arrives.
    2. Call 911 immediately.
    3. Call the Environmental Protection Agency to have a hazmat crew sent to your school.
    4. Tell your teacher immediately and help other students to exit the area until the spill is cleaned up. Show

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