Download Thermo PT

Name: ________________________ Class: ___________________ Date: __________
ID: A
Thermo test
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
____
____
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1. Thermal energy is
A. the energy stored within the structural units of chemical substances.
B. the energy associated with the random motion of atoms and molecules.
C. solar energy, i.e. energy that comes from the sun.
D. energy available by virtue of an object's position.
2. Chemical energy is
A. the energy stored within the structural units of chemical substances.
B. the energy associated with the random motion of atoms and molecules.
C. solar energy, i.e. energy that comes from the sun.
D. energy available by virtue of an object's position.
3. Heat is
A. a measure of temperature.
B. a measure of the change in temperature.
C. a measure of thermal energy.
D. a measure of thermal energy transferred between two bodies at different
temperature.
4. An exothermic reaction causes the surroundings to
A. increase in temperature
B. become acidic.
C. decrease in temperature.
D. expand.
5. Calculate the amount of heat necessary to raise the temperature of 135.0 g of water from 50.4°F to
85.0°F. The specific heat of water = 4.184 J/g°C.
A. 1.1 kJ
B. 10.9 kJ
C. 16.6 kJ
D. 19.5 kJ
6. Three separate 3.5g blocks of Al, Cu, and Fe at 25 °C each absorb 0.505 kJ of heat. Which block
reaches the highest temperature? The specific heats of Al, Cu, and Fe are 0.900 J/g°C, 0.385J/g°C,
and 0.444 J/g°C, respectively.
A. Al
B. Cu
C. Fe
D. Al and Cu
1
Name: ________________________
____
ID: A
7. A beaker contains 115 g of ethanol at 18.2°C. If the ethanol absorbs 1125 J of heat without losing
____
8.
____
9.
____ 10.
____ 11.
____ 12.
heat to the surroundings, what will be the final temperature of the ethanol? The specific heat of
ethanol is 2.46 J/g°C.
A. 4.08°C
B. 14.1°C
C. 18.4°C
D. 22.2°C
A 22.0 g block of copper at 45°C absorbs 2.50 kJ of heat. Given the specific heat of Cu is 0.385
J/g°C what will be the final temperature of the Cu?
A. 45°C
B. 340.°C
C. 295°C
D. 30.°C
If 10.6 moles of water at 35°C absorbs 12.30 kJ, what is the final temperature of the water? The
specific heat of water is 4.184 J/g°C.
A. 15°C
B. 20°C
C. 35°C
D. 50.°C
The specific heat of gold is 0.129 J/g°C. What is the molar heat capacity of gold?
A. 0.039 J/mol°C
B. 0.129 J/mol°C
C. 39.0 kJ/mol°C
D. 25.4 J/mol°C
Suppose a 50.0 g block of silver (specific heat = 0.2350 J/g°C) at 100°C is placed in contact with a
50.0 g block of iron (specific heat = 0.4494 J/g°C) at 0°C, and the two blocks are insulated from the
rest of the universe. The final temperature of the two blocks
A. will be higher than 50°C.
B. will be lower than 50°C.
C. will be exactly 50°C.
D. is unrelated to the composition of the blocks.
Naphthalene combustion can be used to calibrate the heat capacity of a bomb calorimeter. The heat
of combustion of naphthalene is –40.1 kJ/g. When 0.8210 g of naphthalene was burned in a
calorimeter containing 1,000. g of water, a temperature rise of 4.21°C was observed. What is the
heat capacity of the bomb calorimeter excluding the water?
A. 1.76 kJ/°C
B. 3.64 kJ/°C
C. 7.8 kJ/°C
D. 15.3 kJ/°
2
Name: ________________________
ID: A
____ 13. A 100. mL sample of 0.200 M aqueous hydrochloric acid is added to 100. mL of 0.200 M aqueous
____ 14.
____ 15.
____ 16.
____ 17.
ammonia in a calorimeter whose heat capacity (excluding any water) is 480. J/K. The following
reaction occurs when the two solutions are mixed.
HCl(aq) + NH3(aq)  NH4Cl(aq)
The temperature increase is 2.34°C. Calculate H per mole of HCl and NH3 reacted.
A. –154 kJ/mol
B. –1.96 kJ/mol
C. 1.96 kJ/mol
D. 154 kJ/mol
A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter. The total heat
capacity of the calorimeter plus water was 5,760 J/°C. If the temperature rise of the calorimeter with
water was 0.570°C, calculate the enthalpy of combustion of magnesium.
Mg(s) + 1/2O2(g)  MgO(s)
A. –3280 kJ/mol
B. –602 kJ/mol
C. –24.8 kJ/mol
D. 106 kJ/mol
The combustion of pentane produces heat according to the equation
C5H12(l) + 8O2(g)  5CO2(g) + 6H2O(l)
Hrxn= –3,510 kJ/mol
3
How many grams of CO2 are produced per 2.50  10 kJ of heat released?
A. 0.0809 g
B. 3.56 g
C. 31.3 g
D. 157 g
An average home in Colorado requires 20. GJ of heat per month. How many grams of natural gas
(methane) must be burned to supply this energy?
CH4(g) + 2O2(g)  CO2(g) + 2H2O(l) Hrxn= –890.4 kJ/mol
–4
A. 7.1  10 g
B. 1.4  103 g
C. 3.6  105 g
D. 1.4  104 g
Given the thermochemical equation 2SO2(g) + O2(g)  2SO3(g), Hrxn= –198 kJ/mol, how much
heat is evolved when 600. g of SO2 is burned?
A. 5.46  10–2 kJ
B. 928 kJ
C. 1.85  103 kJ
D. 3.71  103 kJ
3
Name: ________________________
ID: A
____ 18. Methanol (CH3OH) burns according to the equation
____ 19.
____ 20.
____ 21.
____ 22.
____ 23.
2CH3OH(l) + 3O2(g)  2CO2(g) + 4H2O(l), Hrxn = –1454 kJ/mol.
How much heat, in kilojoules, is given off when 75.0 g of methanol is burned?
A. 727 kJ
B. 3.22  103 kJ
C. 1.45  103 kJ
D. 1.70  103 kJ
Calcium oxide and water react in an exothermic reaction:
CaO(s) + H2O(l)  Ca(OH)2(s) Hrxn = –64.8 kJ/mol
How much heat would be liberated when 7.15 g CaO(s) is dropped into a beaker containing 152g
H2O?
A. 1.97  10–3 kJ
B. 8.26 kJ
C. 508 kJ
D. 547 kJ
According to the first law of thermodynamics:
A. Energy is neither lost nor gained in any energy transformations.
B. Perpetual motion is possible.
C. Energy is conserved in quality but not in quantity.
D. Energy is being created as time passes. We have more energy in the universe now
than when time began.
The heat of solution of KCl is 17.2 kJ/mol and the lattice energy of KCl(s) is 701.2 kJ/mol. Calculate
the total heat of hydration of 1.00 mol of gas phase K+ ions and Cl– ions.
A. –718 kJ
B. –684 kJ
C. 684 kJ
D. 718 kJ
The heat of solution of LiCl is –37.1 kJ/mol, and the lattice energy of LiCl(s) is 828 kJ/mol.
Calculate the total heat of hydration of 1.00 mol of gas phase Li+ ions and Cl– ions.
A. –865 kJ
B. –791 kJ
C. 791 kJ
D. 865 kJ
The total heat of hydration of 1.00 mol of gas phase Li+ ions and Cl – ions is –865 kJ. The lattice
energy of LiCl(s) is 828 kJ/mol. Calculate the heat of solution of LiCl.
A. –1,693 kJ/mol
B. –37 kJ/mol
C. 37 kJ/mol
D. 1,693 kJ/mol
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Name: ________________________
ID: A
____ 24. 10.1 g CaO is dropped into a styrofoam coffee cup containing 157 g H2O at 18.0°C. If the following
____ 25.
____ 26.
____ 27.
____ 28.
reaction occurs, then what temperature will the water reach, assuming that the cup is a perfect
insulator and that the cup absorbs only a negligible amount of heat? (the specific heat of water =
4.18 J/g°C)
CaO(s) + H2O(l)  Ca(OH)2(s) Hrxn = –64.8 kJ/mol
A. 18.02°C
B. 35.8°C
C. 42.2°C
D. 117°C
Calculate the amount of work done, in joules, when 2.5 mole of H2O vaporizes at 1.0 atm and 25°C.
Assume the volume of liquid H2O is negligible compared to that of vapor. (1 Latm = 101.3 J)
A. 61.1 J
B. 518 J
C. 5.66 kJ
D. 6.19 kJ
A gas is compressed in a cylinder from a volume of 20.0 L to 2.0 L by a constant pressure of 10.0
atm. Calculate the amount of work done on the system.
A. –1.81  104 J
B. –180 J
C. 180 J
D. 1.81  104 J
Calculate the amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of
zinc dissolves in excess acid at 30.0°C.
Zn(s) + 2H+(aq)  Zn2+(aq) + H2(g)
A. w = +22.4 kJ
B. w = +24.9 kJ
C. w = 0
D. w = –19.3 kJ
A gas is allowed to expand, at constant temperature, from a volume of 1.0 L to 10.1 L against an
external pressure of 0.50 atm. If the gas absorbs 250 J of heat from the surroundings, what are the
values of q, w, and E?
A.
B.
C.
D.
A
B
C
D
5
Name: ________________________
ID: A
____ 29. The heat of solution of ammonium nitrate is 26.2 kJ/mol. If a 5.368 g sample of NH4NO3 is added
____ 30.
____ 31.
____ 32.
____ 33.
____ 34.
____ 35.
to 40.0 mL of water in a calorimeter at 23.5°C, what is the minimum temperature reached by the
solution? (The specific heat of water = 4.18 J/g°C; the heat capacity of the calorimeter = 650. J/°C.)
A. –7.7°C
B. 14.3°C
C. 20.8°C
D. 21.4°C
Which one of the following substances is expected to have the highest boiling point?
A. Br2
B. Cl2
C. F2
D. I2
Which one of the following substances is expected to have the lowest melting point?
A. BrI
B. CsI
C. LiI
D. NaI
Which one of the following substances is expected to have the highest boiling point?
A. HBr
B. HCl
C. HF
D. HI
Which one of the following substances is expected to have the highest melting point?
A. CH4
B. CCl4
C. CO
D. C(diamond)
Which one of the following substances should exhibit hydrogen bonding in the liquid state?
A. NH3
B. H2
C. H2S
D. CH4
Which two properties are more typical of molecular compounds than of ionic compounds?
i.
They are gases or liquids at room temperature.
ii. They have high melting points.
iii. Solids do not conduct electricity, but liquids do.
iv. Atoms share electrons.
A.
B.
C.
D.
i and vi
i and iii
ii and iii
ii and iv
6
Name: ________________________
ID: A
____ 36. Which of the following characteristics indicates the presence of weak intermolecular forces in a
liquid?
A. a low heat of vaporization
B. a high critical temperature
C. a low vapor pressure
D. a high boiling point
____ 37. Which of the following properties indicates the presence of strong intermolecular forces in a liquid?
A. a low heat of vaporization
B. a low critical temperature
C. a low vapor pressure
D. a low boiling point
____ 38. For which of the following species are the dispersion forces strongest?
A. C4H10
B. C5H12
C. C6H14
D. C8H18
____ 39. The intermolecular forces present in CO include which of the following?
I.
dipole-dipole
II.
ion-dipole
III. dispersion
IV. hydrogen bonding
I, II, III, and IV
I and III
I, III, and IV
I and II
____ 40. Each of the following substances is a liquid at –50°C. Place these liquids in order of increasing
vapor pressure: dimethyl ether (CH3OCH3), propane (C3H8), and ethanol (CH3CH2OH).
A. ethanol < propane < dimethyl ether
B. ethanol < dimethyl ether < propane
C. propane < dimethyl ether < ethanol
D. dimethyl ether < ethanol < propane
____ 41. Which of the following would be expected to have the highest vapor pressure at room temperature?
A. ethanol, bp = 78°C
B. methanol, bp = 65°C
C. water, bp = 100°C
D. acetone, bp = 56°C
____ 42. The boiling points of propanol (CH3CH2CH2OH) and pentanol (CH3CH2CH2CH2CH2OH) are 97°C
and 137°C, respectively. The boiling point of butanol (CH3CH2CH2CH2OH) is predicted to be:
A. < 97°C
B. > 137°C
C. > 97°C and < 137°C
D. 97°C
A.
B.
C.
D.
7
Name: ________________________
ID: A
____ 43. The boiling points of chloromethane (CH3Cl) and dichlormethane (CH2Cl2) are – 24 °C and 40.°C
____ 44.
____ 45.
____ 46.
____ 47.
____ 48.
____ 49.
____ 50.
respectively. The boiling point of trichloromethane (CHCl3) is predicted to be:
A. < – 24 °C
B. > 40.°C
C. > – 24 °C and < 40.°C
D. – 24 °C
Arrange the following in order of increasing melting point: NaCl, H2O, CH4, C6H4(OH)2
A. NaCl < H2O < CH4 < C6H4(OH)2
B. CH4 < H2O < NaCl < C6H4(OH)2
C. CH4 < H2O < C6H4(OH)2 < NaCl
D. CH4 < C6H4(OH)2 < H2O < NaCl
Which one of the following substances should exhibit hydrogen bonding in the liquid state?
A. PH3
B. He
C. CH3OH
D. CH4
Which one of the following substances should exhibit hydrogen bonding in the liquid state?
A. SiH4
B. H2
C. H2S
D. CH3NH2
Which of following can form hydrogen bonds with water molecules?
(1) Na+ (2) CH3COOH (3) C2H6 (4) CH3NH2
A. (1) and (2)
B. (1) and (3)
C. (2) and (3)
D. (2) and (4)
Each of the following substances is a gas at 25°C and 1 atmosphere pressure. Which one will
liquefy most easily when compressed at a constant temperature?
A. F2
B. H2
C. HF
D. SiH4
Which of the following is not true with regard to water?
A. Water has a high heat capacity.
B. Water has an unusually high boiling point.
C. Water can form hydrogen bonds.
D. Ice is more dense than liquid water.
Which property of water allows a razor blade to float on it without sinking?
A. viscosity
B. surface tension
C. density
D. specific heat
8
Name: ________________________
ID: A
____ 51. The structural form of the element Ge closely resembles the structure of
A. C (diamond).
B. N (diatomic).
C. As (tetrahedral).
D. S (S8 ring).
____ 52. Which one of the following substances crystallizes as a covalent crystal?
A. CaO
B. SiO2
C. CO2
D. Pb
____ 53. Which one of the following crystallizes in a metallic lattice?
A. C
B. NaMnO4
C. K
D. LiClO4
____ 54. A liquid boils when its
A. vapor pressure is exactly 1 atmosphere.
B. vapor pressure is equal to, or greater than, the external pressure pushing on it.
C. temperature is equal to 273 K (standard temperature).
D. temperature is greater than room temperature.
____ 55. The heat capacity of liquid water is 4.18 J/g°C and the heat of vaporization is 40.7 kJ/mol. How
many kilojoules of heat must be provided to convert 1.00 g of liquid water at 67°C into 1.00 g of
steam at 100°C?
A. 40.8 J
B. 2.2 kJ
C. 2,400 J
D. 22.7 kJ
____ 56. The specific heat of liquid ethanol, C2H5OH(l), is 2.46 J/g°C and the heat of vaporization is 39.3
kJ/mol. The boiling point of ethanol is 78.3 °C. What amount of enthalpy is required to heat 50.0 g
of liquid ethanol from 23.0 °C to ethanol vapor at 78.3 °C?
A. 42.7 kJ
B. 49.5 kJ
C. 179 kJ
D. 1970kJ
9
Name: ________________________
ID: A
____ 57. Use the graph of vapor pressure to determine the normal boiling point of O2.
84 K
88 K
90 K
92 K
____ 58. What mass of water would need to evaporate from your skin in order to dissipate 1.7  105 J of heat
from your body?
H2O(l)  H2O(g) Hvap = 40.7 kJ/mol
A. 58.4 g
B. 75.2 g
C. 418 g
D. 7.52  104 g
____ 59. Which of the following constants is/are needed to calculate the amount of energy required to heat
30.5g of H2O(s) at –25.0°C to H2O(l) at 55.0°C?

Hfus (H2O)

Hvap (H2O)
III. specific heat of H2O(s)
IV. specific heat of H2O(l)
V.
specific heat of H2O(g)
A.
B.
C.
D.
A.
B.
C.
D.
I, II, III, IV, and IV
III and IV
I, II, III, and IV
I, III, and IV
10
Name: ________________________
ID: A
____ 60. Which of the following constants is/are needed to calculate the amount of energy required to heat
12.0g of H2O(l) at 30.0°C to H2O(l) at 85.0°C?

Hfus (H2O)

Hvap (H2O)
III. specific heat of H2O(s)
IV. specific heat of H2O(l)
V.
specific heat of H2O(g)
I and IV
II and IV
IV only
I, II, and IV
Solid iodine has a vapor pressure of 1.0 mmHg at 39°C. How many moles of iodine will sublime
into a 500. mL flask at this temperature? If the volume of the flask is doubled at constant
temperature, what will happen to the equilibrium vapor pressure of I2? (Assume some solid I2 is
always present in the container.)
A. 2.1  10–4 mol; vapor pressure increases
B. 2.0  10–2 mol; vapor pressure increases
C. 2.6  10–5 mol; no change in vapor pressure
D. 2.1  10–4 mol; no change in vapor pressure
3.59 g of water was introduced into an evacuated 1.50 L flask at 30°C. What mass of water will
evaporate? (Vapor pressure of water at 30°C is 31.82 mmHg.)
A. 2.52  10–3 g
B. 0.04187 g
C. 0.0455g
D. 0.4187 g
Octane is a liquid component of gasoline. Given the following vapor pressures of octane at various
temperatures, estimate the boiling point of octane in Leadville, Colorado, where the atmospheric
pressure is 496 mmHg.
400 mmHg @ 104°C, 500 mmHg @ 111°C, 600 mmHg @ 117°C, 700 mmHg @ 122°C, 760 mmHg
@ 125°C
A. 125°C
B. 120°C
C. 115°C
D. 110°C
The molar enthalpy of vaporization of carbon disulfide is 26.74 kJ/mol, and its normal boiling point
is 46°C. What is the vapor pressure of CS2 at 0°C?
A. 4160 torr
B. 447 torr
C. 313 torr
D. 139 torr
A.
B.
C.
D.
____ 61.
____ 62.
____ 63.
____ 64.
11
Name: ________________________
ID: A
____ 65. The normal boiling point of methanol (CH3OH) is 64.6°C. Given that the vapor pressure of
methanol is 75.0 torr at 15.2°C, calculate the molar enthalpy of vaporization of methanol.
A. 0.383 kJ/mol
B. 3.00 kJ/mol
C. 27.5 kJ/mol
D. 38.0 kJ/mol
____ 66. Find the temperature at which water boils on a day in the mountains when the barometric pressure is
593 mmHg. (Given: the heat of vaporization of water is 40.79 kJ/mol)
A. 41.5°C
B. 68.1°C
C. 93.1°C
D. 97.0°C
____ 67. Based on the phase diagram shown below, how will the melting point of the substance change if the
pressure is increased above 1 atm?
The melting point will decrease.
The melting point will remain the same.
The melting point will increase.
The substance will not melt at pressures of 1 atm and above; instead, the solid
sublimes to form the gas phase.
____ 68. Which of these species would you expect to have the lowest standard entropy (S°)?
A. CH4(g)
B. HF(g)
C. NH3(g)
D. H2O(g)
____ 69. Which of these species has the highest entropy (S°) at 25°C?
A. CH3OH(l)
B. CO(g)
C. MgCO3(s)
D. H2O(l)
A.
B.
C.
D.
12
Name: ________________________
ID: A
____ 70. Arrange the following substances in the order of increasing entropy at 25°C.
A.
B.
C.
D.
HF(g), NaF(s), SiF4(g), SiH4(g), Al(s)
lowest  highest
SiF4(g) < SiH4(g) < NaF(s) < HF(g) < Al(s)
HF(g) < Al(s) < NaF(s) < SiF4(g) < SiH4(g)
Al(s) < NaF(s) < HF(g) < SiH4(g) < SiF4(g)
Al(s) < HF(g) < NaF(s) < SiF4(g) < SiH4(g)
____ 71. Which one of the following reactions would you expect to have the lowest S°?
A. CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)
B. C2H2(g) + 5/2O2(g)  2CO2(g) + H2O(g)
C. C2H4(g) + O2(g)  2CO2(g) + 2H2O(g)
D. C2H6(g) + 7/2O2(g)  2CO2(g) + 3H2O(g)
____ 72. Which response includes all of the following processes that are accompanied by an increase of
entropy?
I and III
II and III
I, II and III
II only
____ 73. Without reference to a table, arrange these reactions according to increasing S.
1) CH4(g) + H2O(g)  CO(g) + 3H2(g)
2) C(s) + O2(g)  CO2(g)
3) H2O2(l)  H2O(l) + 1/2O2(g)
A. 1 < 3 < 2
B. 2 < 3 < 1
C. 2 < 1 < 3
D. 3 < 2 < 1
____ 74. Arrange these reactions according to increasing S.
1) H2O(g)  H2O(l)
2) 2NO(g)  N2(g) + O2(g)
3) MgCO3(s)  MgO(s) + CO2(g)
A. 1 < 2 < 3
B. 2 < 3 < 1
C. 3 < 2 < 1
D. 2 < 1 < 3
A.
B.
C.
D.
13
Name: ________________________
ID: A
____ 75. Which of the following processes would be accompanied by an increase in entropy?
A. H2O(g)  H2O(s)
B. H2O(l)  H2O(s)
C. H2O(g)  H2O(l)
D. H2O(s)  H2O(g)
____ 76. Aluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from
further corrosion.
4Al(s) + 3O2(g)  2Al2O3(s)
Using the thermodynamic data provided below, calculate S° for this reaction.
Al(s)
O2(g)
Al2O3(s)
S°(J/Kmol)
28.3
205.0
50.99
182.3 J/Kmol
131.5 J/Kmol
–182.3 J/Kmol
–626.2 J/Kmol
____ 77. Determine S° for the reaction SO3(g) + H2O(l)  H2SO4(l).
S°(J/Kmol)
SO3
256.2
H2O
69.9
H2SO4
156.9
A.
B.
C.
D.
A.
B.
C.
D.
169.2 J/Kmol
1343.2 J/Kmol
–169.2 J/Kmol
–29.4 J/Kmol
14
Name: ________________________
ID: A
____ 78. Calculate S° for the reaction SO2(s) + NO2(g)  SO3(g) + NO(g).
SO2(g)
SO3(g)
NO(g)
NO2(g)
S°(J/Kmol)
248.5
256.2
210.6
240.5
53.6 J/Kmol
–53.6 J/Kmol
–22.2 J/Kmol
474.8 J/Kmol
____ 79. Calculate S° at 25°C for the reduction of PbO(s), 2PbO(s) + C(s)  2Pb(s) + CO2(g) given these
absolute entropies:
S° (J/Kmol)
PbO(s)
69.45
C(s)
5.7
Pb(s)
64.89
CO2(g)
213.6
A.
B.
C.
D.
+198.8 J/Kmol
+488.0 J/Kmol
–203.3 J/Kmol
+353.6 J/Kmol
____ 80. Which of the following is consistent with a spontaneous process in the forward direction?
A. Suniv > 0, G < 0, TSuniv > 0
B. Suniv < 0, G > 0, TSuniv < 0
C. Suniv > 0, G < 0, TSuniv < 0
D. Suniv < 0, G < 0, TSuniv < 0
____ 81. Which of the following is consistent with a nonspontaneous process in the forward direction?
A. Suniv > 0, G < 0, TSuniv > 0
B. Suniv < 0, G > 0, TSuniv < 0
C. Suniv > 0, G < 0, TSuniv < 0
D. Suniv < 0, G < 0, TSuniv < 0
____ 82. Which of the following is consistent with a spontaneous endothermic reaction?
A. H > 0, S < 0, G < 0
B. H > 0, S > 0, G < 0
C. H < 0, S < 0, G < 0
D. H < 0, S > 0, G > 0
A.
B.
C.
D.
15
Name: ________________________
ID: A
____ 83. Aluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from
further corrosion.
4Al(s) + 3O2(g)  2Al2O3(s)
Calculate G° for this reaction, given that G°f of aluminum oxide is –1576.4 kJ/mol.
A. –3152.8 kJ/mol
B. –1576.4 kJ/mol
C. –788.2 kJ/mol
D. 1576.4 kJ/mol
____ 84. Calculate G° for the reaction 3NO2(g) + H2O(l)  2HNO3(l) + NO(g).
H2O(l)
HNO3(l)
NO(g)
NO2(g)
G°f (kJ/mol)
–237.2
–79.9
86.7
51.8
8.7 kJ/mol
192 kJ/mol
–414 kJ/mol
–192 kJ/mol
____ 85. The normal melting point sulfur is 113 °C. If a sample of solid sulfur is at 95 °C, Predict the signs of
H, S, and G for the melting process at this temperature.
A. H > 0, S > 0, G < 0
B. H > 0, S > 0, G > 0
C. H > 0, S < 0, G < 0
D. H < 0, S > 0, G > 0
____ 86. The normal boiling point of acetic acid is 118.1°C. If a sample of the acetic acid is at 125.2°C,
Predict the signs of H, S, and G for the boiling process at this temperature.
A. H > 0, S > 0, G < 0
B. H > 0, S > 0, G > 0
C. H > 0, S < 0, G < 0
D. H < 0, S > 0, G > 0
____ 87. The equilibrium constant at 427°C for the reaction N2(g) + 3H2(g)
2NH3(g) is Kp = 9.4  10–5.
Calculate the value of G° for the reaction under these conditions.
A. –33 kJ/mol
B. –54 kJ/mol
C. 54 kJ/mol
D. 33 kJ/mol
A.
B.
C.
D.
16
Name: ________________________
ID: A
____ 88. Calculate the equilibrium constant for the decomposition of water
2H2O(l)
2H2(g) + O2(g)
at 25°C, given that G°f (H2O(l)) = –237.2 kJ/mol.
0.83
6.3  10–84
2.5  10–42
1.6  1083
Nitrosyl chloride (NOCl) decomposes at elevated temperatures according to the equation
2NO(g) + Cl2(g).
2NOCl(g)
Calculate Kp for this reaction at 227°C. (H° = 81.2 kJ/mol, S° = 128 J/Kmol)
A. 1.59  10–2
B. 2.10  10–7
C. 62.8
D. 4.90  106
The equilibrium constant for the reaction AgBr(s)
Ag+(aq) + Br– (aq) is the solubility product
–13
constant, Ksp = 7.7  10 at 25°C. Calculate G for the reaction when [Ag+] = 1.0  10–2 M and
[Br–] = 1.0  10–3 M. Is the reaction spontaneous or nonspontaneous at these concentrations?
A. G = 69.1 kJ/mol, nonspontaneous
B. G = –69.1 kJ/mol, spontaneous
C. G = 97.5 kJ/mol, spontaneous
D. G = 40.6 kJ/mol, nonspontaneous
For the reaction 2C(graphite) + H2(g)  C2H2(g), G°= +209.2 kJ/mol at 25°C. If P(H2) = 100.
atm, and P(C2H2) = 0.10 atm, calculate G for this reaction.
A. +207.8 kJ/mol
B. +226.3 kJ/mol
C. +192.1 kJ/mol
D. +17.3 kJ/mol
For the reaction 2NO(g) + O2(g)  2NO2(g) if initially P(NO) = 1.5 atm, P(O2) = 1.4 atm, and
P(NO2) = 2.0 atm, calculate G for this reaction at 25°C. The following data is valid at 25°C:
Gf° (kJ/mol)
NO
86.7
NO2
51.8
A.
B.
C.
D.
____ 89.
____ 90.
____ 91.
____ 92.
A.
B.
C.
D.
–69.9 kJ/mol
–69.2 kJ/mol
522.1 kJ/mol
–79.9 kJ/mol
17
Name: ________________________
ID: A
____ 93. Determine the equilibrium constant (Kp) at 25°C for the reaction
CO(g) + H2O(g)
CO2(g) + H2(g)
G° = –28.5 kJ/mol.
2.9  10–60
1.0  10–4
1.2
1.0  105
Kw for the auto-ionization of water, H2O(l)  H+(aq) + OH– (aq), is 1.0  10–14. What are the signs
(+/–) of S° and H° for the reaction at 25°C?
A. S° = (+) and H° = (+)
B. S° = (+) and H° = (–)
C. S° = (–) and H° = (+)
D. S° = (–) and H° = (–)
The reaction rates of many spontaneous reactions are actually very slow. Which of these statements
is the best explanation for this observation?
A. Kp for the reaction is less than one.
B. The activation energy of the reaction is large.
C. G° for the reaction is positive.
D. Such reactions are endothermic.
The solubility product constant at 25°C for AgI(s) in water has the value 8.3  10–17. Calculate Grxn
at 25°C for the process AgI(s)
Ag+(aq) + I– (aq) where [Ag+] = 9.1  10–9 and [I–] = 9.1  10–9.
A. +4.4 kJ/mol
B. +91.7 kJ/mol
C. 0.0 kJ/mol
D. –91.7 kJ/mol
Find the temperature at which the reaction N2O4(g) 2NO2(g) will be in equilibrium when both
gases are present at partial pressures of 1.00 atm.
A.
B.
C.
D.
____ 94.
____ 95.
____ 96.
____ 97.
NO2(g)
N2O4(g)
A.
B.
C.
D.
H°f (25°C)
33.85 kJ/mol
9.66 kJ/mol
300°C
28°C
55°C
32°C
18
G°f (25°C)
51.8 kJ/mol
98.29 kJ/mol
Name: ________________________
ID: A
____ 98. A sample of solid naphthalene is introduced into an evacuated flask. Use the data below to calculate
the equilibrium vapor pressure of naphthalene (C10H8) in the flask at 35°C.
C10H8(s)
C10H8(g)
H°f (25°C)
78.5 kJ/mol
150.6 kJ/mol
G°f (25°C)
201.6 kJ/mol
224.1 kJ/mol
890. mmHg
0.21 mmHg
696 mmHg
0.086 mmHg
____ 99. Find the temperature at which Kp = 4.00 for the reaction N2O4(g)
2NO2(g). [Given: at 25°C, for
NO2(g), H°f = 33.85 kJ/mol, S° = 240.46 J/molK; for N2O4(g), H°f = 9.66 kJ/mol, S° = 304.3
J/molK; assume that H° and S° are independent of temperature.]
A. 197 °C
B. 56 °C
C. 36 °C
D. 79 °C
____ 100. Find the temperature at which Kp = 42.0 for the reaction H2(g) + I2(g)
2HI(g). [Given: at 25°C,
for H2(g), H°f = 0, S° = 131.0 J/molK; for I2(g), H°f = 62.26 kJ/mol, S° = 260.6 J/molK; for
HI(g), H°f = 25.9 kJ/mol, S° = 206.3 J/molK; assume that H° and S° are independent of
temperature.]
A. 1040 K
B. 168 K
C. 539 K
D. 1400 K
A.
B.
C.
D.
19
ID: A
Thermo test
Answer Section
MULTIPLE CHOICE
1. ANS:
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2. ANS:
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B
EK.5.B.2
A
EK.5.B.2
D
EK.5.B.1
A
EK.5.C.2
B
EK.5.A.2
B
EK.5.A.2
D
EK.5.A.2
B
EK.5.A.2
D
EK.5.A.2
D
EK.5.A.2
B
EK.5.A.2
B
EK.5.A.2
A
EK.5.A.2
B
EK.5.A.2
D
EK.5.B.2
C
EK.5.B.2
B
EK.5.B.2
D
EK.5.B.2
B
EK.5.B.2
A
EK.5.B.2
B
EK.2.C.2
PTS: 1
DIF: Easy
REF: Section: 6.1
PTS: 1
DIF: Easy
REF: Section: 6.1
PTS: 1
DIF: Medium
REF: Section: 6.2
PTS: 1
DIF: Easy
REF: Section: 6.2
PTS: 1
DIF: Medium
REF: Section: 6.5
PTS: 1
DIF: Easy
REF: Section: 6.5
PTS: 1
DIF: Medium
REF: Section: 6.5
PTS: 1
DIF: Medium
REF: Section: 6.5
PTS: 1
DIF: Medium
REF: Section: 6.5
PTS: 1
DIF: Easy
REF: Section: 6.5
PTS: 1
DIF: Medium
REF: Section: 6.5
PTS: 1
DIF: Medium
REF: Section: 6.5
PTS: 1
DIF: Difficult
REF: Section: 6.5
PTS: 1
DIF: Difficult
REF: Section: 6.5
PTS: 1
DIF: Medium
REF: Section: 6.4
PTS: 1
DIF: Medium
REF: Section: 6.4
PTS: 1
DIF: Medium
REF: Section: 6.4
PTS: 1
DIF: Medium
REF: Section: 6.4
PTS: 1
DIF: Medium
REF: Section: 6.4
PTS: 1
DIF: Easy
REF: Section: 6.3
PTS: 1
DIF: Medium
REF: Section: 6.7
1
ID: A
22. ANS:
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23. ANS:
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45. ANS:
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A
EK.2.C.2
B
EK.2.C.2
B
EK.5.A.2
D
EK.5.B.2
D
EK.5.B.2
D
EK.5.B.2
A
EK.5.B.2
D
EK.5.A.2
D
EK.2.B.2
A
EK.2.B.2
C
EK.2.B.2
D
EK.2.D.4
A
EK.2.B.2
A
EK.2.D.4
A
EK.5.B.3
C
EK.5.B.3
D
EK.2.B.2
B
EK.2.B.2
B
EK.5.B.3
D
EK.5.B.3
C
EK.2.B.2
B
EK.2.B.2
C
EK.2.B.2
C
EK.2.B.2
PTS: 1
DIF: Medium
REF: Section: 6.7
PTS: 1
DIF: Medium
REF: Section: 6.7
PTS: 1
DIF: Medium
REF: Section: 6.5
PTS: 1
DIF: Medium
REF: Section: 6.3
PTS: 1
DIF: Medium
REF: Section: 6.3
PTS: 1
DIF: Medium
REF: Section: 6.3
PTS: 1
DIF: Medium
REF: Section: 6.3
PTS: 1
DIF: Difficult
REF: Section: 6.5
PTS: 1
DIF: Easy
REF: Section: 11.2
PTS: 1
DIF: Easy
REF: Section: 11.2
PTS: 1
DIF: Easy
REF: Section: 11.2
PTS: 1
DIF: Easy
REF: Section: 11.6
PTS: 1
DIF: Medium
REF: Section: 11.2
PTS: 1
DIF: Medium
REF: Section: 11.6
PTS: 1
DIF: Easy
REF: Section: 11.8
PTS: 1
DIF: Easy
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.2
PTS: 1
DIF: Medium
REF: Section: 11.2
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.2
PTS: 1
DIF: Medium
REF: Section: 11.2
PTS: 1
DIF: Medium
REF: Section: 11.2
PTS: 1
DIF: Medium
REF: Section: 11.2
2
ID: A
46. ANS:
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69. ANS:
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D
EK.2.B.2
D
EK.2.B.2
C
EK.5.B.3
D
EK.2.A.1
B
EK.2.A.1
A
EK.2.D.3
B
EK.2.D.3
C
EK.2.D.2
B
EK.5.B.3
C
EK.5.B.3
B
EK.5.B.3
C
EK.5.B.3
B
EK.5.B.3
D
EK.5.B.3
C
EK.5.B.3
C
EK.5.B.3
C
EK.5.B.3
D
EK.5.B.3
D
EK.5.B.3
D
EK.5.B.3
C
EK.5.B.3
C
EK.5.B.3
B
EK.5.E.1
B
EK.5.E.1
PTS: 1
DIF: Medium
REF: Section: 11.2
PTS: 1
DIF: Medium
REF: Section: 11.2
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.3
PTS: 1
DIF: Medium
REF: Section: 11.3
PTS: 1
DIF: Medium
REF: Section: 11.6
PTS: 1
DIF: Medium
REF: Section: 11.6
PTS: 1
DIF: Medium
REF: Section: 11.6
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Difficult
REF: Section: 11.8
PTS: 1
DIF: Difficult
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.8
PTS: 1
DIF: Medium
REF: Section: 11.9
PTS: 1
DIF: Easy
REF: Section: 17.3
PTS: 1
DIF: Easy
REF: Section: 17.3
3
ID: A
70. ANS:
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90. ANS:
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92. ANS:
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93. ANS:
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C
EK.5.E.1
B
EK.5.E.1
A
EK.5.E.1
B
EK.5.E.1
A
EK.5.E.1
D
EK.5.E.1
D
EK.5.E.2
C
EK.5.E.2
C
EK.5.E.1
A
EK.5.E.2
A
EK.5.E.3
B
EK.5.E.3
B
EK.5.E.3
A
EK.5.E.3
A
EK.5.E.3
B
EK.5.E.3
A
EK.5.E.3
C
EK.6.D.1
B
EK.6.D.1
A
EK.6.D.1
D
EK.6.D.1
C
EK.6.D.1
B
EK.6.D.1
D
EK.6.D.1
PTS: 1
DIF: Medium
REF: Section: 17.3
PTS: 1
DIF: Medium
REF: Section: 17.3
PTS: 1
DIF: Medium
REF: Section: 17.3
PTS: 1
DIF: Medium
REF: Section: 17.3
PTS: 1
DIF: Medium
REF: Section: 17.3
PTS: 1
DIF: Easy
REF: Section: 17.3
PTS: 1
DIF: Medium
REF: Section: 17.4
PTS: 1
DIF: Medium
REF: Section: 17.4
PTS: 1
DIF: Medium
REF: Section: 17.3
PTS: 1
DIF: Medium
REF: Section: 17.4
PTS: 1
DIF: Medium
REF: Section: 17.5
PTS: 1
DIF: Medium
REF: Section: 17.5
PTS: 1
DIF: Medium
REF: Section: 17.5
PTS: 1
DIF: Medium
REF: Section: 17.5
PTS: 1
DIF: Medium
REF: Section: 17.5
PTS: 1
DIF: Medium
REF: Section: 17.5
PTS: 1
DIF: Medium
REF: Section: 17.5
PTS: 1
DIF: Medium
REF: Section: 17.6
PTS: 1
DIF: Medium
REF: Section: 17.6
PTS: 1
DIF: Medium
REF: Section: 17.6
PTS: 1
DIF: Difficult
REF: Section: 17.6
PTS: 1
DIF: Medium
REF: Section: 17.6
PTS: 1
DIF: Medium
REF: Section: 17.6
PTS: 1
DIF: Medium
REF: Section: 17.6
4
ID: A
94. ANS:
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95. ANS:
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96. ANS:
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97. ANS:
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98. ANS:
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99. ANS:
OBJ:
100. ANS:
OBJ:
A
EK.5.E.3
B
EK.5.E.2
C
EK.6.D.1
C
EK.6.D.1
B
EK.6.D.1
D
EK.6.D.1
A
EK.6.D.1
PTS: 1
DIF: Medium
REF: Section: 17.5
PTS: 1
DIF: Easy
REF: Section: 17.4
PTS: 1
DIF: Medium
REF: Section: 17.6
PTS: 1
DIF: Difficult
REF: Section: 17.6
PTS: 1
DIF: Difficult
REF: Section: 17.6
PTS: 1
DIF: Difficult
REF: Section: 17.6
PTS: 1
DIF: Difficult
REF: Section: 17.6
5