Download A 4 mole ideal gas system undergoes an adiabatic process where it

A 4 mole ideal gas system undergoes an adiabatic
process where it expands and does 20 J of work on its
environment. How much heat is received by the
system?
1.
2.
3.
4.
-20 J
zero
+5 J
+20 J
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A 5 mole ideal gas system undergoes an adiabatic free
expansion, going from an initial volume of 10 liters to a
final volume of 20 liters. How much work is done by the
system during this adiabatic free expansion?
1.
2.
3.
4.
-50 J
-10 J
zero
+50 J
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A heat engine receives 6000 J of heat from its
combustion process and loses 4000 J through
the exhaust and friction. What is its efficiency?
1.
2.
3.
4.
33%
40%
67%
73%
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
If a heat engine has an efficiency of 30% and its
power output is 600 W, what is the rate of heat
input from the combustion phase?
1.
2.
3.
4.
1800 W
2400 W
2000 W
3000 W
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A steam turbine operates at a boiler temperature of 450
K and an exhaust temperature of 300 K. What is the
maximum theoretical efficiency of this system?
1.
2.
3.
4.
24
50
33
67
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A 4 mole ideal gas system undergoes an adiabatic
process where it expands and does 20 J of work on its
environment. What is its change in internal energy?
1.
2.
3.
4.
-20 J
-5 J
zero
+20 J
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
The maximum theoretical thermodynamic efficiency of a
heat engine operating between hot and cold reservoirs
is a function of which of the following?
1.
2.
3.
4.
hot reservoir temperature
only
cold reservoir
temperature only
both hot and cold
reservoir temperatures
none of these choices are
valid
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
During an isobaric process which one of
the following does not change?
1.
2.
3.
4.
volume
temperature
internal energy
pressure
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A 2 mole ideal gas system is maintained at a
constant volume of 4 liters; if 100 J of heat is
added, what is the work done by the system?
1.
2.
3.
4.
zero
5.0 J
6.7 J
20 J
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A 2 mole ideal gas system is maintained at a constant
volume of 4 liters; if 100 J of heat is added, what is the
change in internal energy of the system?
1.
2.
3.
4.
zero
50 J
67 J
100 J
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
According to the second law of thermodynamics, which
of the following applies to the heat received from a high
temperature reservoir by a heat engine operating in a
complete cycle?
1. must be completely
converted to work
2. equals the entropy
increase
3. converted completely
into internal energy
4. cannot be completely
converted to work
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
An adiabatic free expansion
refers to the fact that
1.
2.
3.
4.
no heat is transferred
between a system and its
surroundings.
the pressure remains
constant.
the temperature remains
constant.
the volume remains
constant.
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
According to the first law of thermodynamics, the
difference in heat gained by a system and the work
done by that same system is equivalent to which of the
following?
1. entropy change
2. internal energy
change
3. temperature
change
4. specific heat
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
If an ideal gas does positive work on its surroundings,
then which one of the following choices may be
assumed with regard to the gas?
1. temperature
increases
2. volume increases
3. pressure increases
4. internal energy
decreases
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
In an isovolumetric process by an ideal
gas, the system's heat gain is equivalent
to a change in which one of the following?
1.
2.
3.
4.
temperature
volume
pressure
internal energy
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A one kilogram chunk of ice at 0°C melts, absorbing
80,000 cal of heat in the process. Which of the following
best describes what happens to this system?
1. increased entropy
2. lost entropy
3. entropy maintained
constant
4. work converted to
energy
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
According to the second law of thermodynamics, for any
process that may occur within an isolated system, which
of the following choices applies?
1. entropy remains
constant
2. entropy increases
3. entropy decreases
4. none of these
choices applies
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Which of the following choices is an
appropriate unit for measuring entropy
changes?
1.
2.
3.
4.
joule-K
newton-K
joule/s
joule/K
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
An electrical power plant manages to send 88% of the heat
produced in the burning of fossil fuel into the water-to-steam
conversion. Of the heat carried by the steam, 40% is converted
to the mechanical energy of the spinning turbine. Which of the
following choices best describes the overall efficiency of the
heat-to-work conversion in the plant (as a percentage)?
1.
2.
3.
4.
25% 25% 25% 25%
greater than 88%
64%
less than 40%
40%
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
1
2
3
4
If one could observe the individual atoms making up a piece of
matter and note that during a process of change their motion
somehow became more orderly, then one may assume which of
the following in regard to the system?
25% 25% 25% 25%
1. increases in entropy
2. decreases in entropy
3. gains in thermal
energy
4. positive work done on
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Which of the following choices best corresponds to what
is required by the second law of thermodynamics for
any process taking place in an isolated system?
1. entropy decreases
2. entropy remains
constant
3. entropy increases
4. entropy equals
work done
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
An ideal gas is maintained at a constant pressure of
70,000 N/m2 during an isobaric process while its
volume decreases by 0.2 m3 . What work is done by the
system on its environment?
1.
2.
3.
4.
14,000 J
350,000 J
-14,000 J
-35,000 J
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
In an isothermal process for an ideal gas system (where
the internal energy doesn't change), which of the
following choices best corresponds to the value of the
work done by the system?
1. its heat intake
2. twice its heat intake
3. the negative of its
heat intake
4. twice the negative
of its heat intake
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A system which receives 70 J of heat from its
environment and does 20 J of work will have
what net change in its internal energy?
1.
2.
3.
4.
90 J
50 J
zero
-70 J
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A heat engine performs 2000 J of work while
rejecting 5000 J of heat to the cold-temperature
reservoir. What is the efficiency of the engine?
1.
2.
3.
4.
71.4%
60.0%
40.0%
28.6%
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A heat engine operating between a pair of hot and cold
reservoirs with respective temperatures of 500 K and
200 K will have what maximum efficiency?
1.
2.
3.
4.
60
50
40
30
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
An 800 MW electric power plant has an efficiency of
30%. It loses its waste heat in large cooling towers.
Approximately how much waste heat (in MJ) is
discharged to the atmosphere per second?
1.
2.
3.
4.
1200 MJ
1800 MJ
800 MJ
560 MJ
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A gasoline engine with an efficiency of 30% operates
between a high temperature T1 and a low temperature T2
= 320 K. If this engine operates with Carnot efficiency,
what is the high-side temperature T1 ?
1.
2.
3.
4.
1066 K
868 K
614 K
457 K
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A Florida home is kept cool in the summer by an air conditioner.
The outside temperature is 36°C and the inside of the home is
kept at 18°C. If 50 MJ of heat is removed from the house per
hour, what is the minimum power that must be provided to run
the air conditioner?
25% 25% 25% 25%
1.
2.
3.
4.
214 W
430 W
860 W
1720 W
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
The surface of the sun is approximately 5700 K and the
temperature of the Earth's surface is about 290 K. What
total entropy change occurs when 1000 J of heat
energy is transferred from the sun to the Earth?
1.
2.
3.
4.
2.89 J/K
3.27 J/K
3.62 J/K
3.97 J/K
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
The efficiency of a Carnot engine
operating between 100°C and 0°C is most
nearly
1.
2.
3.
4.
7%
15%
27%
51%
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
What is the coefficient of performance of a
refrigerator that operates with Carnot efficiency
between temperatures -7°C and +31°C?
1.
2.
3.
4.
7.0
9.1
10.0
13.2
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
How much work is required, using an ideal Carnot
refrigerator, to remove 1 J of heat energy from helium
gas at 4 K and reject this heat to a room temperature
(293 K) environment?
1.
2.
3.
4.
13.9 J
26.7 J
52.6 J
72.3 J
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
On a cold day, a heat pump is used to extract heat
energy from the outside air at -5°C and bring it into the
+20°C house. What minimum amount of work must be
done to bring 1000 J of heat energy into the house?
1.
2.
3.
4.
40.0 J
60.0 J
85.3 J
100.1 J
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Suppose a power plant uses a Carnot engine to generate
electricity, using the atmosphere at 300 K as the low
temperature reservoir. Suppose the power plant produces 1 x
106 J of electricity with the hot reservoir at 500° K during one
day and then produces 1 x 106 J of electricity with the hot
reservoir at 600° K during the second day. On these two days
the thermal pollution was
25% 25% 25% 25%
1.
2.
greatest on the first day
greatest on the second
day
the same on both days
zero on both days
3.
4.
1
2
3
4
5
6
7
8
9
10
11
12
21
22
23
24
25
26
27
28
29
30
31
32
41
42
43
44
45
46
47
48
49
50
13
14
33
34
1
15
16
35
36
2
17
18
37
38
3
19
20
39
40
4
A bottle containing an ideal gas has a volume of 2m3 and a
pressure of 1 x 105 N/m2 at a temperature of 300° K. The bottle
is placed against a metal block that is maintained at 900° K and
the gas expands as the pressure remains constant until the
temperature of the gas reaches 900° K. The change in internal
energy of the gas is +6 x 105 J. How much heat did the gas
absorb?
25% 25% 25% 25%
1.
2.
3.
4.
0
4 x 105 J
6 x 105 J
10 x 105 J
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
1
2
3
4
A bottle containing an ideal gas has a volume of 2m3 and a
pressure of 1 x 105 N/m2 at a temperature of 300° K. The bottle is
placed against a metal block that is maintained at 900° K and the
gas expands as the pressure remains constant until the
temperature of the gas reaches 900° K. The change in internal
energy of the gas is 6 x 10 5 J. What is the change in entropy of
the block?
25% 25% 25% 25%
1.
2.
3.
4.
0
+670 J/K
-440 J/K
-1100 J/K
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
1
2
3
4
When gasoline is burned, it gives off 46,000 J/gram of
heat energy. If an automobile uses 13.0 kg of gasoline
per hour with an efficiency of 21%, what is the average
horsepower output of the engine? (1 HP = 746 W)
1.
2.
3.
4.
46.76 HP
108.7 HP
67.2 HP
33.6 HP
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
An ideal gas at pressure, volume, and temperature, P0 , V0 , and
T0 , respectively, is heated to point A, allowed to expand to point B at
constant temperature 2T0 , and then returned to the original condition. The
internal energy increases by 3P0V0 /2 going from point B to point T0 . In
going around this cycle once, which quantity equals zero?
25% 25% 25% 25%
1.
The total change in
internal energy of the gas.
The total work done by
the gas.
The total heat added to
the gas.
All three are zero.
2.
3.
4.
1
2
3
4
5
6
7
8
9
10
11
12
13
141 15
16 2 17
18 3 19
20 4
21
22
23
24
25
26
27
28
29
30
31
32
33
34
36
38
40
41
42
43
44
45
46
47
48
49
50
35
37
39
An ideal gas at pressure, volume, and temperature, P0 , V0 , and
T0 , respectively, is heated to point A, allowed to expand to point B
at constant temperature 2T0 , and then returned to the original
condition. The internal energy increases by 3P0V0 /2 going from
point B to point T0 . How much heat left the gas from point B to
point T0 ?
25% 25% 25% 25%
1.
2.
3.
4.
0
POVO/2
3 POVO/2
5 POVO/2
1
2
3
4
5
6
7
8
9
10
11
12
131 14
15 2 16
17 3 18
19
21
22
23
24
25
26
27
28
29
30
31
32
33
35
37
39
41
42
43
44
45
46
47
48
49
50
34
36
38
4
20
40
For which system is heat usually
transferred from the cooler part of the
system to warmer material?
25% 25% 25% 25%
1.
2.
3.
4.
a stove as it heats up water
a refrigerator that is running
an electric fan that is running
none of these, because it is
impossible to transfer heat in
this manner
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
An ideal gas at pressure, volume, and temperature, P0 , V0 , and
T0 , respectively, is heated to point A, allowed to expand to point B
at constant temperature 2T0 , and then returned to the original
condition. The internal energy increases by 3P0V0 /2 going from
point B to point T0 . How much heat left the gas from point T0 to
25% 25% 25% 25%
point A?
1.
2.
3.
4.
0
POVO/2
3 POVO/2
5 POVO/2
1
2
3
4
5
6
7
8
9
10
11
12
13
114
15
216
17
318
19
420
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Heat is applied to an ice-water mixture to
melt the ice. In this process
1. work is done by the
ice-water mixture.
2. the temperature
increases.
3. the internal energy
increases.
4. all of these will occur.
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
What is the work done by the gas as it expands from
pressure P1 and volume V1 to pressure P2 and volume
V2 along the indicated straight line?
25% 25% 25% 25%
(P1 + P2) (V2 – V1) /2
(P1 + P2) (V2 – V1)
(P1 - P2) (V2 – V1) /2
(P1 - P2) (V2 + V1)
1.
2.
3.
4.
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
As the ideal gas expands from pressure P1 and volume
V1 to pressure P2 and volume V2 along the indicated
straight line, it is possible that
25% 25% 25% 25%
1.
the temperature stays
constant.
the internal energy
decreases.
the gas is changing state.
all of these are impossible
for this particular graph.
2.
3.
4.
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Which of the following increases the
internal energy of a solid metal rod?
1. Raising it to a greater
height.
2. Throwing it through
the air.
3. Having the rod
conduct heat.
4. Having the rod absorb
heat.
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
An electrical generating plant operates at a boiler temperature of
220°C and exhausts the unused heat into a nearby river at 19°C. If
the generating plant has a power output of 800 megawatts and if
the actual efficiency is 3/4ths the theoretical efficiency, how much
heat per second must be delivered to the boiler? (0°C = 273 K)
25% 25% 25% 25%
1.
2.
3.
4.
5200 megawatts
1810 megawatts
3620 megawatts
2600 megawatts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
1
33
34
2
35
36
3
37
38
394
40
41
42
43
44
45
46
47
48
49
50
During each cycle of operation a refrigerator absorbs 55
cal from the freezer compartment and expels 85 cal to
the room. How much work input is required to operate
the system? (1 cal = 4.186 J)
25% 25% 25% 25%
1.
2.
3.
4.
125 J
146 J
356 J
565 J
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
During each cycle of operation a refrigerator absorbs 55 cal
from the freezer compartment and expels 85 cal to the room.
If one cycle occurs every 10 s, how many minutes will it take
to freeze 500 gm of water, initially at 0°C? (Lv = 80 cal/gm)
25% 25% 25% 25%
1.
2.
3.
4.
800 min
4400 min
121 min
60 min
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
1
34
35
2
36
37
3
38
394
40
41
42
43
44
45
46
47
48
49
50
An electrical generating plant operates at a boiler
temperature of 220°C and exhausts the unused heat
into a nearby river at 18°C. What is the maximum
theoretical efficiency of the plant? (0°C = 273 K)
1.
2.
3.
4.
61%
32%
21%
41%
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
On a winter day an ideal heat pump operates with an
outdoor temperature of 5°C while indoors it is 22°C.
What is the theoretical coefficient of performance of this
heat pump? (0°C = 273 K)
1.
2.
3.
4.
3
7
17
21
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
A 1 kg block of ice at 0°C and 1 ATM melts
completely to water. What is its change in
entropy? (For ice, Lf = 3.34 x 105 J/kg)
1.
2.
3.
4.
3340.0 J/K
2168.7 J/K
613.6 J/K
1223.4 J/K
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
One kilogram of water at the 1 ATM boiling point (100° C)
is heated until all the water vaporizes. What is its change
in entropy? (For water, Lvap = 2.26 x 106 J/kg)
1.
2.
3.
4.
12118 J/K
6059 J/K
3030 J/K
1223 J/K
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
What is the change in entropy (DS) when one mole of
silver (108 g) is completely melted at 961°C? (The heat
of fusion of silver is 8.82 x 104 J/kg.)
1.
2.
3.
4.
5.53 J/K
7.72 J/K
9.91 J/K
12.10 J/K
25% 25% 25% 25%
1
2
3
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
An avalanche of ice and snow of mass 1800 kg slides a
vertical distance of 160 meters down a mountainside. If the
temperature of the ice, snow, mountain and surrounding air
are all at 0°C, what is the change in entropy of the universe?
1.
2.
3.
4.
25% 25% 25% 25%
31015 J/K
10338 J/K
3165 J/K
1055 J/K
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
134
35
236
37
338
39
440
41
42
43
44
45
46
47
48
49
50