THERMODYNAMICS ASSESSMENT
PART 1: Matching: Match the vocabulary word with the corresponding
definition. Each word will be used once.
A. Absolute Zero
E. First Law of Thermodynamics
B. Carnot Efficiency
F. Heat Engine
C. Adiabatic
G. Second Law of Thermodynamics
D. Entropy
H. Thermodynamics
1. __________________The study of heat and its transformation into mechanical
energy.
2. __________________When the kinetic energy of a substance approaches zero, no
more energy can be extracted from the substance, and the substance has
reached its lowest possible temperature.
3. __________________A measure of the amount of disorder.
4. __________________Any device that changes internal energy into mechanical
work.
5. __________________Heat will ever of itself flow from a cold object to a hot object.
6. __________________Whenever heat is added to a system, it transforms to an equal
amount of some other form of energy.
7. __________________The process of compression or expansion of a gas so that no
heat enters or leaves a system.
8. __________________Ideal efficiency = T hot- T cold/ T hot
PART 2: Multiple Choices
1. __________________The lowest possible temperature in nature is
a. -273 C
b. 4 K
c. 0 C
2. __________________A volume of air has a temperature of 0 degrees Celsius. An
equal volume of air that is twice as hot has a temperature of about
a. 0C
b. 2C
c. 100C
d. 273C
e. none of the above
3. __________________The first law of thermodynamics is a restatement of the
a. Carnot cycle
b. Law of heat addition
c. Principle of entropy
d. Conservation of energy
e. None of the above
4. __________________Adiabatic processes occur in
a. The earth’s mantle
b. The oceans
c. The atmosphere
d. All of the above
5. __________________The greater the difference in temperature between input
reservoir and output reservoir for a heat engine, the
a. Less the efficiency
b. Greater the efficiency
c. Neither- efficiency does not depend on temperature difference
6. __________________When mechanical work is done on a system, there can be an
increase in its
a. Temperature
b. Internal energy
c. Both temperature and internal energy
d. Neither temperature nor internal energy
7. __________________If a volume of air is swept upward with no heat input or
output, its temperature
a. Decreases
b. Remains the same
c. increases
8. __________________When work is done by a system and no heat is added to it, the
temperature of the system
a. Remains unchanged
b. Decreases
c. Increases
9. __________________When a volume of air is compressed and no heat enters or leaves,
the air temperature will
a. Increase
b. Remain unchanged
c. decrease
10. __________________Suppose the temperature of the input reservoir in a heat engine
doesn't change. As the sink temperature is lowered, the efficiency of the engine
a. Stays the same
b. Decreases
c. increases
11. __________________Two identical blocks of iron, one at 10 degrees C and the other at
20 degrees C, are put in contact. Suppose the cooler block cools to 5 degrees C
and the warmer block warms to 25 degrees C. This would violate the
a. First law of thermodynamics
b. 2nd law of thermodynamics
c. Both of the above
d. None of the above
12. __________________As a system becomes more disordered, entropy
a. Remains the same
b. Decreases
c. increases
13. __________________Systems that are left alone tend to move toward a state of
a. More entropy
b. Les entropy
c. No entropy
14. __________________Entropy measures
a. Temperature as volume increases
b. Temperature as pressure increases
c. Temperature at constant pressure
d. Messiness
e. Temperature at constant volume
15. __________________Entropy is closely related to the
a. Second law of thermodynamics
b. First law of thermodynamics
c. Both of the above
d. None of the above.
16. __________________Running a refrigerator with its door open in a hot room makes the
room
a. Cooler
b. Warmer
c. None of the above
17. __________________In buildings that are electrically heated, turning the lights on
a. Does not waste energy
b. Wastes energy
c. Does neither of the above
18. __________________Pull a closed plastic bag of dry air quickly down from a high
elevation and the bag of air will become
a. Cooler
b. Hotter
c. Neither of the above
19. __________________Cool a sample of air from zero on the Celsius scale to near zero
on the absolute scale and the air loses
a. Volume
b. Pressure
c. Both A and B
d. Neither A nor B
20. __________________Ceramic automobile engines that operate at higher temperatures
will be
a. Less efficient
b. More efficient
c. Neither of the above
21. __________________The ideal efficiency for a heat engine operating between
temperatures of 2050 K and 310 K is
a. 15%
b. 50%
c. 25%
d. 85%
e. none of the above
22. __________________80 joules of heat is added to a system that performs 55 Joules of
work. The internal energy change of the system is
a. 0 J
b. 25 J
c. 55 J
d. 135 J
PART 2: Plug & Chug
1. Calculate the ideal efficiency of a heat engine that takes in energy at 1000K
and expels heat to a reservoir at 400 K.
2. Calculate the ideal efficiency of a ship’s boiler when steam comes out at 545
K, pushes through a steam turbine, and exits into a condenser that is kept at
300 K by circulating through seawater.
3. Calculate the ideal efficiency of a steam turbine that has a hot reservoir of
110 C high pressure steam and a sink at 30C.
4. In a heat engine drived by ocean temperature differences, the heat source
(water near the surface) is at 292 K and the heat sink (deeper water) is at
283 K. Calculate the idea efficiency of the engine.
5. What is the idea efficiency of an engine of both its hot reservoir and exhaust
are the same temperature (say- 500 K)?
6. If a blob of air is initially at 2C and it expands adiabatically while flowing
upward alongside a mountain a vertical distance of 2 km, what will its
temperature be? What about when it has risen 10 km?
PART 3: Short Answer
1. We know that warm air rises. If this is true, why is it colder at the top of the
mountain than at the bottom (you may want to draw a picture to aid in your
explanation).
2. Is it every possible to entirely convert a given amount of heat into mechanical
energy? Is it possible to entirely convert a given amount of mechanical
energy into heat? In other words is there any situation in reality where a
process or machine is 100% efficient? Explain.
3. Suppose one wishes to cool a kitchen by leaving the refrigerator door open
and closing the kitchen door and windows. What will happen to the room
temperature? Why?
4. What do you think the phrase “thermal pollution” means?