Sample Test: Heat and Heat Transfer
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2
3
4
5
6
7
Heat transfer by convection occurs when
A.
electromagnetic waves travel from one place to another through a vacuum.
B.
electrons bump into other electrons.
C.
atoms give off heat in the form of electromagnetic waves.
D.
particles of a fluid move from place to place.
E.
none of the above
The reason you can hold your fingers beside (but not above) a candle flame without getting hurt is that
A. hot air rises. B. air is a poor heat conductor. C. hot-air convection currents travel upward.
D. all of the above
Heat travels from the sun to Earth by
A.
conduction. B. radiation C. convection D. insulation E. vacuumization
Energy transfer by convection is primarily restricted to
A. gases.
B. liquids.
C. solids.
D. Liquids and gases. E. Solids, liquids, and gases.
A piece of metal will feel colder than a piece of wood at the same temperature. Why?
A. Metals, in general, have a higher specific heat capacity than wood. B. Metals, in general, are good heat
conductors.
C. Metals are colder than wood. D. Wood, in general, is a poor insulator.
E. Metal atoms are moving more slowly, on the average, than wood atoms.
Temperature is related mostly to the _____.
A. average molecular kinetic energy in a substance
B. total potential energy of an object
C. specific heat of a substance
D. total energy of an object
E. average kinetic energy of an object
Specific heat capacity is related to the amount of internal energy _____.
A. transferred by one molecule B. one molecule contains C. a specific object has
D. transferred by one object
E. needed to change the temperature of one gram of a substance one degree
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Some molecules are able to absorb large amounts of energy easily . Materials composed of such molecules
would have _____.
A. high specific heat capacities B. low specific heat capacities
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Which releases the most energy, 100 grams of 100°C water cooling to 50°C, or 100 grams of iron at 100°C
cooling to 50°C? (The specific heat of iron is 0.50 J/g°C and water is 4.186 J/g°C)
A. Iron B. Water C. both the same
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Which includes a release of energy by a substance:
A. evaporation B. condensation
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The lowest possible temperature in nature is (From Chemistry)
A. 0 ºC B. 100 ºC C. 273 ºC D. 273 K E. 0 K
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Thermal expansion (objects expand or grow larger when heated) occurs in a piece of metal which is heated. The expansion
is most likely a result of
A. atoms becoming larger B. an increase in density C. atoms gaining electrons D. atoms moving farther apart
1. The drawing shows three metal blocks that were just recently stacked together. Draw
arrows to show the direction of heat flow.
2. One end of a metal rod is put into a fire while a person holds the other end. Very quickly,
the metal rod becomes too hot for the person to handle. By what method of heat transfer (conduction,
convection, or radiation) did the heat travel through the rod?
3. A cook wants to raise 400 g (.4 kg) of water from 20 ºC to its boiling point of 100 ºC. How much heat does the
cook need to add to the water? (specific heat of water = 4186 J/g ºC)
4. The masses and specific heats of some samples of liquids are shown in the table below.
Samples
Mass (kg)
Specific Heat
a) The temperature of which sample will rise the most when
Capacity
1000 J is added? Explain your answer.
(J/kg · K)
water
0.750
4200
b) The temperature of which sample will rise the least when
cooking oil
0.750
2100
1000 J is added? Explain your answer.
glycerin
0.750
2400
methanol
0.750
2500
c) A burner is placed beneath the water which is at 30 °C. If
25,000 J of heat energy is given to the water, what is the final temperature of the water? Show your work.
7. The table below shows initial data from a laboratory demonstration.
Material
Mass (kg)
Tinitial (°C)
Specific Heat
In the demonstration, a heated 0.06 kg copper
Water
0.35
30
4190
pipe was dropped into a beaker of water.
Glass Beaker
0.50
30
500
Students in the class were asked to predict the
Copper Pipe
0.06
550
386
final temperature of the beaker of water when it
reached equilibrium with the copper pipe.
a) If this demonstration took place in a closed insulated beaker, what would be the relationship between the heat
lost by the copper and the heat gained by the water and glass?
b) Assume a 0.12 kg copper pipe was used instead of the given 0.06 kg pipe (both heated to the same initial
temperature). How would this change affect the final temperatures of the water and of the glass beaker?
Explain your answer.
SOLUTIONS – Be sure to try the questions before you look at the solutions.
1
D
2
D
3
B
4
D
5
A
6
A
7
E
8
A
9
B
10
B
1
2
3
4
5A
5B
5C
C to B
and
B to A
Conduc
-tion
133,952
Joules
6
degrees
cooking
oil
water
about
38
11
E
6A
Heat
gained =
heat lost
12
D
6B
Greater
temp
change