1.
Given the following reaction in acidic media:
Fe2+ + Cr2O72–  Fe3+ + Cr3+
answer the following question: The coefficient for water in the balanced reaction is:
a)
b)
c)
d)
e)
2.
1
3
5
7
none of these
Ammonium metavandate reacts with sulfur dioxide in acidic solution as follows (hydrogen ions and H 2O
omitted):
xVO3– + ySO2  xVO2+ + ySO42–
The ratio x : y is
a)
b)
c)
d)
e)
1:1
1:2
2:1
1:3
3:1
3.
When the equation Cl2  Cl– + ClO3– (basic solution) is balanced using the smallest whole-number
coefficients, the coefficient of OH– is:
a)
1
b)
12
c)
3
d)
4
e)
6
4.
When the equation for the following reaction in basic solution is balanced, what is the sum of the coefficients?
MnO2 + HO2–  MnO4–
a)
b)
c)
d)
e)
11
31
14
9
18
Consider a galvanic cell based in the reaction Fe2+ + Cr2O72–  Fe3+ + Cr3+ in acidic solution.
5.
What is the coefficient of Fe3+ in the balanced equation?
a)
6
b)
2
c)
3
d)
4
e)
none of these
6.
Calculate the voltage of the standard cell carrying out this reaction.
a)
0
b)
0.21 V
c)
–0.21 V
d)
0.56 V
e)
–0.56 V
7.
Which of the following is true for the cell shown here? Zn(s)│Zn2+(aq) ║ Cr3+(aq) │Cr(s)
a)
The electrons flow from the cathode to the anode.
b)
The electrons flow from the zinc to the chromium.
c)
The electrons flow from the chromium to the zinc.
d)
The chromium is oxidized.
e)
The zinc is reduced.
8.
A strip of copper is placed in a 1 M solution of copper nitrate and a strip of silver is placed in a 1 M solution of
silver nitrate. The two metal strips are connected to a voltmeter by wires and a salt bridge connects the
solutions. The following standard reduction potentials apply:
Ag+(aq) + e–  Ag(s)
ℰ° = +0.80 V
Cu2+(aq) + 2e–  Cu(s)
ℰ° = +0.34 V
Which of the following statements is false?
a)
b)
c)
d)
e)
9.
Electrons flow in the external circuit from the copper electrode to the silver electrode.
The silver electrode increases in mass as the cell operates.
There is a net general movement of silver ions through the salt bridge to the copper half-cell.
Negative ions pass through the salt bridge from the silver half-cell to the copper half-cell.
Some positive copper ions pass through the salt bridge from the copper half-cell to the silver half-cell.
Which of the following is the strongest oxidizing agent?
MnO4– + 4H+ + 3e–  MnO2 + 2H2O
ℰ° = 1.68 V
I2 + 2e–  2I–
ℰ° = 0.54 V
Zn2+ + 2e–  Zn
ℰ° = –0.76 V
a)
b)
c)
d)
e)
MnO4–
I2
Zn2+
Zn
MnO2
10.
The galvanic cell described by Zn(s)│Zn2+(aq)║Cu2+(aq)│Cu(s) has a standard cell potential of 1.101 volts.
Given that Zn(s)  Zn2+(aq) + 2e– has an oxidation potential of 0.762 volts, determine the reduction potential
for Cu 2 .
a)
1.863 V
b)
–1.863 V
c)
–0.339 V
d)
0.339 V
e)
none of these
11.
What is the cell reaction for the voltaic cell Cr(s) | Cr3+(aq) || Br–(aq) | Br2(g) | Pt?
a)
Cr(s) + 2Br–(aq)
Br2(g) + Cr3+(aq)
3+
–
b)
2Cr (aq) + 6Br (aq)
2Cr(s) + 3Br2(g)
c)
Cr(s) + 3Br2(g)
Cr3+(s) + 2Br–(aq)
d)
2Cr(s) + 3Br2(g)
2Cr3+(aq) + 6Br–(aq)
e)
none of these
12.
Consider the following electrode potentials:
Mg2+ + 2e–  Mg ℰ° = –2.37 V
V2+ + 2e–  V
ℰ° = –1.19 V
Cu2+ + e–  Cu+ ℰ° = 0.16 V
Which one of the reactions below will proceed spontaneously from left to right?
a)
b)
c)
d)
e)
13.
Mg2+ + V  V2+ + Mg
Mg2+ + 2Cu+  2Cu2+ + Mg
V2+ + 2Cu+  V + 2Cu2+
V + 2Cu2+  V2+ + 2Cu+
none of these
Which of the following statements is true concerning the electrochemical cell depicted below?
Ca | Ca2+(aq) || Mn2+(aq) | Mn
Ca2+(aq) + 2e–  Ca(s); ℰ° = –2.87 V
Mn2+(aq) + 2e–  Mn(s); ℰ° = –1.19 V
a)
b)
c)
d)
e)
14.
The cell reaction is spontaneous with a standard cell potential of 1.68 V.
The cell reaction is spontaneous with a standard cell potential of 4.06 V.
The cell reaction is nonspontaneous with a standard cell potential of –1.68 V.
The cell reaction is nonspontaneous with a standard cell potential of –4.06 V.
The cell is at equilibrium.
The reduction potentials for Au3+ and Ni2+ are as follows:
Au3+ + 3e–  Au, ℰ° = +1.50 V
Ni2+ + 2e–  Ni, ℰ° = –0.232 V
Calculate G° (at 25°C) for the reaction:
2Au3+ + 2Ni  3Ni2+ + 2Au
a)
b)
c)
d)
e)
15.
Tables of standard reduction potentials are usually given at 25°C. ℰ° depends on temperature. Which of the
following equations describes the temperature dependence of ℰ°?
nF
a)
ℰ° =
– lnk
RT
b)
ℰ° = H° – TS°
c)
d)
e)
16.
1.00  103 kJ
–7.34  102 kJ
7.34  102 kJ
–1.67  102 kJ
–1.00  103 kJ
H  T S 

nF
nF
H  S 

lnℰ° = –
RT
R
none of these
ℰ° = -
For a reaction in a voltaic cell both H° and S° are positive. Which of the following statements is true?
a)
ℰ°cell will increase with an increase in temperature.
b)
ℰ°cell will decrease with an increase in temperature.
c)
d)
e)
ℰ°cell will not change when the temperature increases.
G° > 0 for all temperatures.
None of the above statements is true.
17.
For a certain reaction, H° = –77.6 kJ and S° = –217 J/K. If n = 3, calculate ℰ° for the reaction at 25°C.
a)
0.0447 V
b)
0.491 V
c)
0.287 V
d)
0.134 V
e)
0.249 V
18.
Determine G° for a cell that utilizes the following reaction:
Cl2(g) + 2Br–(aq)  2Cl–(aq) + Br2(l)
The standard reduction for the chlorine gas is 1.360 volts and the standard reduction for the bromine liquid is
about 1.076 volts.
a)
b)
c)
d)
e)
19.
20.
–470 kJ
–27.4 kJ
–235 kJ
–54.8 kJ
–24.3 kJ
For a particular reaction in a galvanic (voltaic) cell S° is negative. Which of the following statements is true?
a)
ℰ will increase with an increase in temperature.
b)
ℰ will decrease with an increase in temperature.
c)
d)
e)
ℰ will not change when the temperature increases.
G° > 0 for all temperatures.
None of the above statements is true.
A galvanic cell consists of a left compartment with a tin electrode in contact with 0.1 M Sn(NO3)2(aq) and a
right compartment with a lead electrode in contact with 1  10–3 M Pb(NO3)2(aq). The relevant reduction
potentials are:
Pb2+ + 2e–  Pb ℰ° = –0.13 V
Sn2+ + 2e–  Sn
ℰ° = –0.14 V
When this cell is allowed to discharge spontaneously at 25°C, which of the following statements is true?
a)
b)
c)
d)
e)
Electrons will flow from left to right through the wire.
Pb2+ ions will be reduced to Pb metal.
The concentration of Sn2+ ions in the left compartment will increase.
The tin electrode will be the cathode.
No noticeable change will occur, because the cell is at equilibrium.
21.
A concentration cell is constructed using two Ni electrodes with Ni 2+ concentrations of 1.0 M and 1.00  10–4
M in the two half-cells. The reduction potential of Ni2+ is –0.23 V. Calculate the potential of the cell at 25°C.
a)
–0.368 V
b)
+0.132 V
c)
–0.132 V
d)
+0.118 V
e)
+0.0592 V
22.
Which of the following statements is/are correct?
a)
The value of ℰ° is equal to zero in a concentration cell, and the value of ℰ is equal to zero in any cell at
equilibrium.
b)
The value of ℰ° can be equal to zero in a concentration cell, and the value of ℰ must be equal to zero in a
concentration cell.
c)
The values of ℰ° and ℰ are equal to zero in any cell at equilibrium.
d)
e)
ℰ° can never be equal to zero.
At least two of the above choice (A-D) are correct.
23.
Which of the following statements is true about a voltaic cell for which ℰ°cell = 1.00 V?
a)
It has G° > 0.
b)
The system is at equilibrium.
c)
It has K = 1.
d)
The cathode is at a higher energy than the anode.
e)
The reaction is spontaneous.
24.
In order to determine the identity of a particular lanthanide metal (M), a voltaic cell is constructed at 25°C
with the anode consisting of the lanthanide metal as the electrode immersed in a solution of 0.0924 M MCl3,
and the cathode consisting of a copper electrode immersed in a 1.00 M Cu(NO3)2 solution. The two halfreactions are as follows:
M(s) → M3+(aq) + 3e–
Cu2+(aq) + 2e– → Cu(s)
The potential measured across the cell is 2.64 V. What is the identity of the metal?
Reduction Half-Reaction
ℰ° (V)
Cu2+(aq) + 2e– → Cu(s)
0.34
Ce3+(aq) + 3e– → Ce(s)
–2.336
Dy3+(aq) + 3e– → Dy(s)
–2.295
Eu3+(aq) + 3e– → Eu(s)
–1.991
Gd3+(aq) + 3e– → Gd(s)
–2.279
Sm3+(aq) + 3e– → Sm(s)
–2.304
a)
b)
c)
d)
e)
25.
Ce
Eu
Dy
Gd
Sm
Consider the hydrogen–oxygen fuel cell where:
H2(g) + O2(g)
H2O(l)
G° = –237.18 kJ/mol H2
Which of the following statements is true?
a)
b)
c)
d)
e)
At standard conditions, the maximum work the fuel cell could do on the surroundings is 237.18 kJ/mol.
In the real world, the actual amount of useful work the cell can do is less than 237.18 kJ.
More energy is dissipated as waste heat in the fuel cell than in the reversible pathway.
A, B, and C are all true.
A, B, and C are all false.
An antique automobile bumper is to be chrome plated. The bumper, which is dipped into an acidic Cr 2O72–
solution, serves as a cathode of an electrolytic cell. The atomic mass of Cr is 51.996; 1 faraday = 96,485 coulombs.
26.
If oxidation of H2O occurs at the anode, how many moles of oxygen gas will evolve for every 145 grams of
Cr(s) deposited?
a)
4.18
b)
0.697
c)
16.7
d)
11.2
e)
3.72
An antique automobile bumper is to be chrome plated. The bumper, which is dipped into an acidic Cr 2O72–
solution, serves as a cathode of an electrolytic cell. The atomic mass of Cr is 51.996; 1 faraday = 96,485 coulombs.
27.
If the current is 10.0 amperes, how long will it take to deposit 137 grams of Cr(s) onto the bumper?
a)
7.06 h
b)
1.77 days
c)
70.6 min
d)
2.63 min
e)
2 mo, 25 days, 14 h, and 6 s
28.
Electrolysis of a molten salt with the formula MCl, using a current of 3.86 amp for 16.2 min, deposits 1.52 g
of metal. Identify the metal. (1 faraday = 96,485 coulombs)
a)
Li
b)
Na
c)
K
d)
Rb
e)
Ca
29.
Which of the following used to be more precious than gold or silver, due to difficulties refining it?
a)
copper
b)
aluminum
c)
tin
d)
zinc
e)
iron
30.
What mass of chromium could be deposited by electrolysis of an aqueous solution of Cr 2(SO4)3 for 175
minutes using a constant current of 13.0 amperes?
a)
0.187 g
b)
220.7 g
c)
0.409 g
d)
36.8 g
e)
24.5 g
31.
A gas absorbs 0.0 J of heat and then performs 15.2 J of work. The change in internal energy of the gas is
a)
30.4 J
b)
15.2 J
c)
–30.4 J
d)
–15.2 J
e)
none of these
32.
What is the kinetic energy of a 1.50-kg object moving at 86.0 km/hr?
a)
4.28  102 kJ
b)
5.55  103 kJ
c)
4.28  10–4 kJ
d)
8.56  102 kJ
e)
1.79  101 kJ
33.
Which of the following statements correctly describes the signs of q and w for the following exothermic
process at P = 1 atm and T = 370 K?
H2O(g)  H2O(l)
a)
b)
c)
d)
e)
q and w are negative.
q is positive, w is negative.
q is negative, w is positive.
q and w are both positive.
q and w are both zero.
34.
For a particular process q = 20 kJ and w = 15 kJ. Which of the following statements is true?
a)
Heat flows from the system to the surroundings.
b)
The system does work on the surroundings.
c)
E = 35 kJ
d)
All of the above are true.
e)
None of the above are true.
35.
Which of the following statements is correct?
a)
The internal energy of a system increases when more work is done by the system than heat was flowing
into the system.
b)
The internal energy of a system decreases when work is done on the system and heat is flowing into the
system.
c)
The system does work on the surroundings when an ideal gas expands against a constant external
pressure.
d)
All statements are true.
e)
All statements are false.
36.
For a particular process q = –17 kJ and w = 21 kJ. Which of the following statements is false?
a)
Heat flows from the system to the surroundings.
b)
The system does work on the surroundings.
c)
E = +4 kJ
d)
The process is exothermic.
e)
None of the above is false.
37.
One mole of an ideal gas is expanded from a volume of 1.00 liter to a volume of 4.90 liters against a constant
external pressure of 1.00 atm. How much work (in joules) is performed on the surroundings? Ignore
significant figures for this problem. (T = 300 K; 1 L·atm = 101.3 J)
a)
198 J
b)
395 J
c)
1.19  103 J
d)
496 J
e)
none of these
38.
Calculate the work for the expansion of CO 2 from 1.0 to 5.8 liters against a pressure of 1.0 atm at constant
temperature.
a)
4.8 L·atm
b)
5.8 L·atm
c)
0 L·atm
d)
–4.8 L·atm
e)
–5.8 L·atm
39.
A fuel-air mixture is placed in a cylinder fitted with a piston. The original volume is 0.310-L. When the
mixture is ignited, gases are produced and 815 J of energy is released. To what volume will the gases expand
against a constant pressure of 635 mmHg, if all the energy released is converted to work to push the piston?
a)
9.32 L
b)
7.03 L
c)
9.94 L
d)
9.63 L
e)
1.59 L
Ans: c
Algorithm: Yes
Chapter/Section: 6.1
Difficulty: Moderate
Keyword 1: Chemistry
Keyword 2: general chemistry
Keyword 3: thermochemistry
Keyword 4: thermodynamics
Keyword 5: first law of thermodynamics
40.
Which statement is true of a process in which one mole of a gas is expanded from state A to state B?
a)
When the gas expands from state A to state B, the surroundings are doing work on the system.
b)
The amount of work done in the process must be the same, regardless of the path.
c)
It is not possible to have more than one path for a change of state.
d)
The final volume of the gas will depend on the path taken.
e)
The amount of heat released in the process will depend on the path taken.
41.
A chunk of iron at 90.6°C was added to 200.0 g of water at 15.5°C. The specific heat of iron is 0.449 J/g°C,
and the specific heat of water is 4.18 J/g°C. When the temperature stabilized, the temperature of the mixture
was 18.2°C. Assuming no heat was lost to the surroundings, what was the mass of iron added?
a)
468 g
b)
55.5 g
c)
66.9 g
d)
69.4 g
e)
none of these
42.
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.
43.
What is the specific heat capacity of zinc if it requires 146 J to raise the temperature of 15 grams of zinc by
25°C?
a)
2.6 J/g°C
b)
0.39 J/g°C
c)
0.23 J/g°C
d)
0.60 J/g°C
e)
none of these
44.
A 3.9-g sample of Colorado oil shale is burned in a bomb calorimeter, which causes the temperature of the
calorimeter to increase by 5.0°C. The calorimeter contains 1.00 kg of water (heat capacity of H 2O = 4.184
J/g°C) and the heat capacity of the empty calorimeter is 0.10 kJ/°C. How much heat is released per gram of oil
shale when it is burned?
a)
21 kJ/g
b)
42 kJ/g
c)
0 kJ/g
d)
5.5 kJ/g
e)
0.18 kJ/g
45.
If a student performs an endothermic reaction in a calorimeter, how does the calculated value of H differ
from the actual value if the heat exchanged with the calorimeter is not taken into account?
a)
Hcalc would be more negative because the calorimeter always absorbs heat from the reaction.
b)
Hcalc would be less negative because the calorimeter would absorb heat from the reaction.
c)
Hcalc would be more positive because the reaction absorbs heat from the calorimeter.
d)
Hcalc would be less positive because the reaction absorbs heat from the calorimeter.
e)
Hclac would equal the actual value because the calorimeter does not absorb heat.
46.
A bomb calorimeter has a heat capacity of 2.47 kJ/K. When a 0.111-g sample of ethylene (C2H4) was burned
in this calorimeter, the temperature increased by 2.26 K. Calculate the energy of combustion for one mole of
ethylene.
a)
–5.29 kJ/mol
b)
–50.3 kJ/mol
c)
–624 kJ/mol
d)
–0.274 kJ/mol
e)
–1.41  103 kJ/mol
47.
Consider the reaction:
C2 H5 OH(l ) + 3O2 (g )  2CO 2 (g ) + 3H 2 O(l ), H  1.37 × 10 3 kJ
When a 24.8-g sample of ethyl alcohol (molar mass = 46.07 g/mol) is burned, how much energy is released as
heat?
a)
b)
c)
d)
e)
0.538 kJ
0.737 kJ
7.37  102 kJ
3.40  104 kJ
1.86 kJ
48.
The H value for the reaction
g Hg is reacted with oxygen?
a)
0.318 kJ
b)
5.79  103 kJ
c)
28.9 kJ
d)
90.8 kJ
e)
none of these
49.
The total volume of hydrogen gas needed to fill the Hindenburg was 2.01  108 L at 1.00 atm and 24.7°C.
How much energy was evolved when it burned?
H2 (g ) + 12 O2 (g )  H2 O(l ), H  286 kJ
a)
b)
c)
d)
e)
50.
1
2
O2 (g ) + Hg(l )  HgO(s) is -90.8 kJ. How much heat is released when 63.8
8.23  106 kJ
2.84  1010 kJ
2.88  104 kJ
2.35  109 kJ
4.71  109 kJ
Consider the following specific heats of metals.
Metal
Specific Heat
Copper
0.385 J/(g°C)
Magnesium
1.02 J/(g°C)
Tungsten
0.134 J/(g°C)
Silver
0.237 J/(g°C)
Bismuth
0.123 J/(g°C)
If the same amount of heat is added to 25.0 g of each of the metals, which are all at the same initial
temperature, which metal will have the highest temperature?
a)
b)
c)
d)
e)
Copper
Magnesium
Tungsten
Silver
Bismuth