Unit 12 Study Guide
2.
A 5.10-g sample of iron is heated from 36.0oC to
75.0oC. The amount of energy required is 89.46 J. The
specific heat capacity of this sample of iron is
A)
1.78  104 J/g oC
B)
2.22 J/g oC
C)
0.234 J/g oC
D)
0.450 J/g oC
E)
0.158 J/g oC
4.
Which of the following is a valid unit for specific
heat (or specific heat capacity)?
A)
cal/g °C
B)
cal
C)
cal/g
D)
°C
E)
g °C/cal
6.
Calculate the heat given off when 155.5 g of
copper cools from 155.0oC to 23.0oC. The specific heat
capacity of copper is 0.385 J/g oC.
A)
1.38  103 J
B)
9.28  103 J
C)
5.33  104 J
D)
7.90  103 J
E)
none of these
9.
The specific heat capacity of iron is 0.45 J/g oC.
How many joules of energy are needed to warm 1.93 g of
iron from 20.00oC to 29.00oC?
A)
25 J
B)
17 J
C)
39 J
D)
16 J
E)
7.8 J
10.
How many joules of energy would be required to
heat 29.6 g of carbon from 23.6oC to 54.2oC? (Specific
heat capacity of carbon = 0.71 J/goC.)
A)
6.4  102 J
B)
1.7  103 J
C)
1.1  103 J
D)
1.3  103 J
E)
none of these
13.
Assume that 462.0 J of heat is added to 5.00 g of
water originally at 23.0oC. What would be the final
temperature of the water? (Specific heat capacity of water
= 4.184 J/goC.)
A)
22.1 oC
B)
60.1 oC
C)
73.1 oC
D)
45.1 oC
E)
none of these
17.
Calculate  E given the following information:
q = +41 kJ, w = +24 kJ
A)
17 kJ
B)
65 kJ
C)
D)
E)
–65 kJ
–17 kJ
1.7 kJ
 E for a system is 31 kJ. If 175 kJ of work was
19.
done on the system, how much heat was released?
A)
144 kJ
B)
206 kJ
C)
–206 kJ
D)
–144 kJ
E)
–5.6 kJ
20.
2105.34 J of energy is equivalent to how many
calories?
A)
1.98733  10–3 cal
B)
0.503188 cal
C)
2.10534 cal
D)
2109.52 cal
E)
503.188 cal
23.
Express 3.16  105 J in kilocalories.
A)
1.32  106 kcal
B)
7.55  104 kcal
C)
75.5 kcal
D)
316 kcal
E)
1.32  103 kcal
25.
Perform the indicated conversion: 1.359 kcal =
_______________ J
A)
5.686  103 J
B)
5.686 J
C)
5.686  10–3 J
D)
324.8 J
E)
3.079 J
27.
Perform the indicated conversion: 3.16  103
cal = _______________ J
A)
755 J
B)
1.32  104 J
C)
13.2 J
D)
7.55  105 J
E)
1.32  10–3 J
28.
Determine the enthalpy change when 23.5 g of
carbon is reacted with oxygen according to the reaction
 H = –394 kJ/mol
C(s) + O2(g)  CO2(g)
A)
771 kJ
B)
9.26  103 kJ
C)
–771 kJ
D)
–9.26 kJ
E)
8.19 kJ
29.
For the reaction
1
H2(g) + O2(g)  H2O(l)  H = –286 kJ/mol
2
Calculate the enthalpy change when 5.37 g of hydrogen
gas is reacted with excess oxygen.
A)
–53.3 kJ
B)
C)
D)
E)
30.
762 kJ
–762 kJ
1.54  103 kJ
–1.54  103 kJ
38.
Which of the following processes is exothermic?
A)
rolling a ball up a hill
B)
boiling water in a beaker to make steam
C)
allowing meat to thaw after taking it out
of the freezer
D)
reacting hydrogen and oxygen gases to
make water
E)
a popsicle melting on a warm summer day
39.
heat.
__________ is the ability to do work or produce
For the reaction
1
H2(g) + O2(g)  H2O(l)  H = –286 kJ/mol
2
What is the enthalpy change when 17.5 mol of hydrogen
gas reacts with excess oxygen?
A)
16.3 kJ
B)
–16.3 kJ
C)
6.12  10–2 kJ
D)
–5.01  103 kJ
E)
–2.48  103 kJ
31.
For the reaction
1
H2(g) + O2(g)  H2O(l)  H = –286 kJ/mol
2
Calculate the enthalpy change when 2.82 g of water is
produced.
A)
101 kJ
B)
807 kJ
C)
–807 kJ
D)
44.8 kJ
E)
–44.8 kJ
32.
A 100.0-g sample of water at 27.0oC is poured
into a 71.5-g sample of water at 89.0oC. What will be the
final temperature of the water?
A)
85.8oC
B)
318oC
C)
21.4oC
D)
129oC
E)
52.8oC
34.
The specific heat capacity of gold is 0.13 J/goC.
How many calories of energy are needed to warm 0.767 g
of gold from 30.0oC to 39.5oC?
A)
0.95 cal
B)
0.23 cal
C)
1.7 cal
D)
4.0 cal
E)
30 cal
37.
Which of the following statements about energy
is false?
A)
A reaction cannot be exothermic overall if
activation energy is required.
B)
A system is the most stable when it is at
its lowest energy state.
C)
Energy can be defined as whatever is
required to oppose a natural tendency.
D)
Energy transferred into a system can also
be transferred out of the system.
E)
An atom in an excited state can return to
its ground state by releasing visible light.
A)
B)
C)
D)
E)
Gravity
Temperature
Radiation
Matter
Energy
40.
True or false? The law of conservation of energy
states that energy can be converted from one form to
another but can be neither created nor destroyed.
A)
True
B)
False
43.
__________ is a measure of the random motions
of the components of a substance.
A)
Heat
B)
Temperature
C)
Energy
D)
Radiation
E)
Matter
49.
On a cold winter day, a steel metal fence post
feels colder than a wooden fence post of identical size
because
A)
the specific heat capacity of steel is higher
than the specific heat capacity of wood.
B)
the specific heat capacity of steel is lower
than the specific heat capacity of wood.
C)
steel has the ability to resist a temperature
change better than wood.
D)
the mass of steel is less than wood, so it
loses heat faster.
E)
Two of the above statements are true.
50.
According to the first law of thermodynamics,
the energy of the universe is constant. Does this mean that
ΔE is always equal to zero?
A)
Yes, ΔE = 0 at all times, which is why q =
-w.
B)
No, ΔE does not always equal zero, but
this is due only to factors such as friction and
heat.
C)
No, ΔE does not always equal zero
because it refers to the system’s internal energy,
which is affected by heat and work.
D)
No, ΔE never equals zero because work is
always being done on the system or by the
system.
E)
No, ΔE never equals zero because energy
is always flowing between the system and
surroundings.
53.
54.
True or false? Enthalpy is not a state function.
A)
True
B)
False
Consider the following reaction:
 H = -108.7 kJ/mol
ClF + F2  ClF3;
Is the reaction exothermic or endothermic?
A)
exothermic
B)
endothermic
2.
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6.
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37.
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43.
49.
50.
53.
54.
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