3rd quarter review honors chem

UNIT 5 GAS LAWS
1. A gas is compressed and then cooled to its original temperature. Compared to the original conditions the molecules
now
(A)
move faster.
(B)
move slower.
(C)
are farther apart.
(D)
are closer together.
(E)
have contracted in proportion to the pressure applied.
2. Which statement best accounts for the fact that gases can be greatly compressed?
(A)
Molecules occupy space.
(B)
The collisions of molecules are elastic.
(C)
Molecules of gases are in constant motion.
(D)
The molecules of a given gas are identical.
(E)
Molecules of gases are relatively far from each other.
3. The gaseous molecules that have the greatest average velocity at 150 °C are represented by
Atomic Molar Masses
12.0 g·mol–1
19.0 g·mol–1
1.0 g·mol–1
14.0 g·mol–1
16.0 g·mol–1
C
F
H
N
O
(A)
O2
(E)
H2O
(B)
F2
(C)
H2
(D)
N2
4. Which is a basic assumption of the kinetic–molecular theory?
(A)
Particles are in random motion.
(B)
Particles undergo inelastic collisions.
(C)
Particles lose energy with an increase in velocity.
(D)
Particles travel faster as the temperature decreases.
(E)
Particles lose energy when the temperature increases
5. How does the average kinetic energy (KE) of hydrogen molecules compare with that of oxygen molecules when both
gases are at 25 °C?
(A)
They have equal KE’s.
(B)
The KE of hydrogen is 1/4 as great.
(C)
The KE of hydrogen is 1/16 as great.
(D)
The KE of hydrogen is 4 times as great.
6. Equal volumes of oxygen, carbon dioxide, and methane under the same conditions of temperature and pressure
contain the same number of
(A)
atoms.
(D)
electrons.
(B)
molecules.
(E)
neutrons.
(C)
protons.
7. Gases may be most easily liquefied by
(A)
raising the temperature and lowering the pressure.
(B)
raising the pressure and lowering the temperature.
(C)
lowering both the temperature and pressure.
(D)
raising both the temperature and pressure.
(E)
lowering the temperature and keeping the presure unchanged
8. One liter of a certain gas has a mass of 4 g at STP. From this fact, it follows that
(A)
the gas is helium.
(B)
the molar mass of the gas is 4 g·mol–1.
(C)
the molar mass of the gas is 89.6 g·mol–1
(D)
6  1023 molecules of the gas have a mass of 4 g.
(E)
there are two atoms in each molecule of the gas.
9. One liter of oxygen at STP contains approximately the same number of molecules as
(A)
2 L of He at STP.(D)
1/ 5
(B)
1/ 3
L of O3 at STP.
(E)
(C)
l L of CO2 at STP.
L of CH4 at STP.
250 mL of NH3 at STP.
10. A sample of sulfur dioxide gas has a mass of 16 g. The mass of the same number of molecules of nitrogen gas is
Atomic Molar Masses
14.0 g·mol–1
16.0 g·mol–1
32.0 g·mol–1
N
O
S
(A)
7g
(E)
56 g
(B)
14 g
(C)
16 g
(D)
28 g
11. According to the Avogadro Principle, one liter of gaseous hydrogen and one liter of gaseous ammonia contain the
same number of
(A)
atoms at standard conditions.
(B)
molecules at all conditions.
(C)
molecules only at standard conditions.
(D)
atoms if conditions in both containers are the same.
(E)
molecules if conditions in both containers are the same.
12. Which is STP?
(A)
0 °C and 76 mmHg
(D)
100 °C and 76 cmHg
(B)
0 K and 76 mmHg
(E)
273 K and 760 mmHg
(C)
0 K and 760 mmHg
13. In the experimental graph, the extrapolated line intersects the horizontal axis at about –280 °C. Which term is
applied to this value ?
25
20
15
10
5
0
-300
-200
-100
0
T e mpe rature in °C
(A)
triple point
(C)
freezing point
(B)
absolute zero
(D)
critical temperature
100
14. At the same temperature and pressure, which sample of gas contains the same number of molecules as one liter of
oxygen, O2?
(A)
one liter of helium, He
(B)
two liters of neon, Ne
(C)
three liters of carbon dioxide, CO2
(D)
two liters of hydrogen, H2
15. At very low temperatures, the measured volume of a gas is slightly smaller than the volume calculated from the gas
laws. Which is the best explanation?
(A)
The gas molecules have lost some of their elasticity.
(B)
The molecules have become smaller at the lower temperatures.
(C)
The molecules exert attractive forces on each other.
(D)
The molecules have a finite volume that cannot be compressed.
16. At constant volume, why does the pressure of a sample of gas increase as the temperature increases?
(A)
The molecules move faster.
(B)
The molecules become larger.
(C)
The molecular collisions become more elastic.
(D)
The molecules have less free space in which to move
17. The molecules of an ideal gas would
(A)
all be diatomic.
(B)
attract one another more strongly as the pressure increases.
(C)
attract one another more strongly as the temperature increases.
(D)
have negligible size and exert no attraction on one another.
18. Each of three identical containers holds a mole of gas, all at the same temperature.
CH
O
SO
Which gas exerts the greatest pressure? Assume ideal behavior.
(A)
CH4
(B)
O2
(C)
SO2
(D)
They all exert the the same pressure.
19. A weather balloon contains 12 L of hydrogen at 740 mmHg pressure. At what pressure in mmHg will the volume
become 20 L (temperature constant)?
(A)
370
(E)
1480
(B)
444
(C)
760
(D)
1230
20. A gas occupies a 1.5 L container at 25 °C and 2.0 atm. If the gas is transferred to a 3.0 L container at the same
temperature, what will be the new pressure?
(A)
l.0 atm (B)
(E)
5.0 atm
2.0 atm (C)
3.0 atm (D)
4.0 atm
21. Which curve shows the relationship between the volume of an ideal gas (at constant pressure) and its temperature
in kelvins?
B
C
A
0
(A)
A
(B)
B
(C)
D
100
200
300
T e mpe rature , in ke lvins
C
(D)
D
22. A fixed volume of oxygen gas, O2, exerts a pressure of
1.00 atm at a temperature of 25 °C. What is the pressure of the gas when it is heated to 100 °C?
(A)
0.250 atm
(C)
2.50 atm
(B)
1.25 atm
(D)
4.00 atm
23. Which curve represents the relationship between the volume of an ideal gas and its temperature in kelvins at
constant pressure?
(A)
T e mpe rature , K 
(C)
T e mpe rature , K 
(B)
T e mpe rature , K 
(D)
T e mpe rature , K 
24. 100 mL of a gas measured at –l36.5 °C and a pressure of 380 mmHg has at standard conditions a volume of
(A)
100 mL 
(D)
400 mL
(B)
200 mL
(E)
500 mL
(C)
300 mL
25. One liter of gas at STP has a mass of 0.18 g. The molar mass of the gas is approximately
(A)
0. 18 g (B)
(E)
22.40 g
0.36 g (C)
2.00 g (D)
4.00 g
26. A 31 cm3 sample of gas is collected at 37 °C and 720 mmHg. What is its volume at 17 °C and 580 mmHg?
(A)
23 cm3 (B)
27 cm3 (C)
36 cm3 (D)
41 cm3
27. How many moles of a gas are contained in a 100.0 l flask at 2.00 atm and 327˚C ?
(A) .612 moles (B) .333 moles (C) 4.06 moles (D) 9852 moles
28. What will be the volume of 4.00 moles of CO at 27.0˚C and 2280 Torr?
(A) .0474 liters (B) 2.96 moles (C) 22.4 moles (D) 32.8 moles
29. 7 g of a gas occupies 11.2 L at one atmosphere pressure and 546 K. The gas could be
(A)
CO
(B)
Ar
(C)
O2
(D)
CO2
(E)
NH3
30. What is the density of SO2 at STP?
Atomic Molar Masses
O
S
(A)
0.72 g·L–1
(B)
1.43 g·L–1
(C)
2.86 g·L–1
g·mol–1
16
32 g·mol–1

(D)
18.7 g·L–1
(E)
64.0 g·L–1
31. One liter of oxygen is collected by displacement of water. The barometric pressure, corrected for vapor pressure, is
782 mmHg, and the room temperature is 21 °C. The volume of oxygen at STP is
(A)
782 273
1000  760  294 mL
(B)
760 273
1000  782  294 mL
(C)
782 294
1000  760  273 mL
(D)
782 21
1000  760  0 mL
(E)
273 294
1000  760  782 mL
32. A vessel contains 2.50 mol of oxygen gas, 0.50 mol of nitrogen gas, and 1.00 mol of carbon dioxide gas. The total
pressure is 2.00 atm. The partial pressure exerted by the oxygen in the mixture is
(A)
1.25 atm
(D)
2.00 atm
(B)
1.50 atm
(E)
2.50 atm
(C)
1.66 atm
33. What is the partial pressure of the oxygen, O2(g), in a container holding 2.0 mol of oxygen, O2(g), and 3.0 mol of
nitrogen, N2(g) if the total pressure is 800 mm Hg?
(A)
800 mmHg
(D)
400 mmHg
(B)
530 mmHg
(E)
320 mmHg
(C)
480 mmHg
34. A sample of air at 740 mmHg contains 210 cm3 oxygen, O2, 780 cm3 nitrogen, N2, and 10 cm3 other gases. What is
the partial pressure of the oxygen, O2, in mmHg?
(A)
78
(B)
155
(C)
310
(D)
580
UNIT 6 CONDENSED STATE OF MATTER/SOLUTIONS
35. The curve that represents most closely the solubility of a gas in a liquid is,
80
D
C
60
B
40
20
0
(A)
A
(B)
B
A
0°
(C)
C
20 °
40 °
60 °
T e mpe rature in °C
(D)
80 °
D
36. Bubbles rise in a newly opened bottle of a carbonated beverage. This action is explained by the fact that carbon
dioxide is less soluble in water when
(A)
pressure is increased.
(B)
pressure is reduced.
(C)
temperature is increased.
(D)
temperature is reduced.
(E)
liquid carbon dioxide evaporates.
37. In general, the solubilities of gases in water
(A)
decrease as pressure increases.
(B)
are not affected by pressure change.
(C)
are constant for all types of gases.
(D)
are not affected by temperature changes.
(E)
decrease as temperature increases.
38. Which solution contains the greatest mass of solute in 100 g of water? (careful—read all responses)
NaNO
100
KNO
80
K CrO
60
KCl
40
NaCl
20
0
0
20
40
60
80
T e mpe rature in °C
(A)
A saturated solution of NaCl at 100 °C
(B)
A saturated solution of KCl at 50 °C
(C)
A saturated solution of NaNO3 at 25 °C
(D)
A saturated solution of KNO3 at 25 °C
(E)
A saturated solution of K2CrO4 at 50 °C
100
39. Which of these compounds is least soluble in water? (hint—use solubility table!!)
(A)
potassium chloride
(B)
silver chloride
(C)
magnesium chloride
(D)
calcium chloride
(E)
sodium nitrate
40. About how many grams of water would be needed to dissolve 20 g of potassium chlorate at 30 °C?
25 g
20 g
·
15 g
C
10 g
5g
A
B
·
·
D
E
·
·
0g
10 ° 20 ° 30 ° 40 ° 50 ° 60 °
T e mpe rature , °C
(A)
5g
(E)
200 g
(B)
10 g
(C)
20 g
(D)
100 g
41. At a constant temperature in a saturated aqueous salt solution in contact with undissolved salt
(A)
addition of a common ion enables more salt to dissolve.
(B)
the rate of dissolving exceeds that of crystallization.
(C)
the rate of dissolving equals the rate of crystallization of the salt.
(D)
the mass of salt in solution equals the mass of undissolved salt.
(E)
all of the salt is found in the undissolved salt at the bottom of the container.
42. Two salts that are equally soluble at about 46 °C are
120
NaNO
100
80
KBr
60
NaCl
40
20
K Cr O
10
0
Ca(C H O ) 2H O
0° 10° 20° 30° 40° 50° 60° 70° 80°
T e mpe rature in °C
(A)
KBr and NaNO3
(B)
KBr and K2Cr2O7
(C)
NaCl and Ca(C2H3O2)2·2H2O
(D)
K2Cr2O7 and Ca(C2H3O2)2·2H2O
43. Which curve represents the relationship between solubility and temperature of most solids, such as KNO3, in water?
(A)
Te mpe rature
(C)
T e mpe rature
(B)
Te mpe rature
(D)
T e mpe rature
44. Consider the graph:
90
80
70
60
50
40
30
20
10
0
A
B
C
D
0
30
60
90
T e mpe rature in °C
Which compound is most soluble at 30 °C?
(A)
A
(B)
B
(C)
C
(D)
D
45. Which compound on the graph below has the least variation in solubility with a change in temperature from 0° to 80
°C?
100
KBr
80
60
K Cr O
2 2 7
40
NaCl
20
0
.
Ca(C2H3O2) 2 2H2O
10 30 50 70 90
Temperature in °C
(A)
KBr
(C)
K2Cr2O7
(B)
NaCl
(D)
Ca(C2H3O2)2·H2O
46. The curve that represents a substance that is slightly more soluble in hot than in cold water is,
80
E
D
60
C
40
B
20
0
(A)
A
(E)
E
(B)
B
(C)
A
0°
C
20 °
40 °
60 °
T e mpe rature in °C
(D)
80 °
D
47. At 10 °C the substance that is most soluble is represented by curve
80
E
D
60
C
40
B
20
0
(A)
A
(E)
E
(B)
B
(C)
A
0°
C
20 °
40 °
60 °
T e mpe rature in °C
(D)
D
48. Which of these is a non–electrolyte when dissolved in water?
(A)
acetic acid
(D)
sodium chloride
(B)
sulfuric acid
(E)
calcium hydroxide
(C)
ethanol
80 °
49. Which is the best conductor of electricity?
(A)
ether
(D)
sugar solution
(B)
ethanol
(E)
carbon tetrachloride
(C)
vinegar
50. Which solution contains the same total number of ions per liter as 1.0 M FeCl2?
(A)
1.0 M AlCl3
(C)
0.5 M CuSO4
(B)
2.0 M NaCl
(D)
1.5 M KBr
51. Which equation represents the dissolving of barium chloride, BaCl2, in water?
(A)
BaCl2(s)  Ba2+(aq) + Cl2–(aq)
(B)
BaCl2(s)  Ba2+(aq) + 2Cl–(aq)
(C)
BaCl2(s)  Ba(aq) + Cl2(aq)
(D)
BaCl2(s)  Ba(aq) + 2Cl(aq)
52. Which statement explains that a water solution of hydrogen chloride, HCl, is an excellent conductor, while pure
liquid hydrogen chloride does not conduct electricity?
(A)
Water is an electrolyte.
(B)
Hydrogen chloride ionizes in water.
(C)
Hydrogen chloride is a non–electrolyte.
(D)
Hydrogen chloride releases electrons in water.
53. What is the concentration of nitrate ion, NO3–(aq), in a 0.2 M Ba(NO3)2 solution?
Ba(NO3)2(s)  Ba2+(aq) + 2NO3–(aq)
(A)
0.1 M (B)
0.2 M (C)
0.3 M (D)
0.4 M
54. The equation for the dissociation of aluminum chloride is
AlCl3  Al 3+ + 3Cl–
What is the concentration of chloride ion, Cl–, in a 0.30 M AlCl3 solution?
(A)
0.30 M (B)
0.60 M (C)
0.90 M (D)
1.2 M
55. The phrase “like dissolves like” is frequently used in describing solutions. What is “like”?
(A)
their densities
(C)
their heats of formation
(B)
their molar masses
(D)
their molecular polarities
56. Which ion will form a precipitate when added to a 1 M hydroxide ion, OH–(aq), solution?
(A)
Cs+(aq)
(C)
Fe3+(aq)
(B)
NH4+(aq)
(D)
SO42–(aq)
57. How many moles of potassium hydroxide, KOH, are needed to prepare 2 L of a 2 M solution?
(A)
1
(B)
2
(C)
3
(D)
4
58. How many moles of copper(II) ion, Cu2+, are present in 200 mL of a 0.250 M solution of CuSO4?
(A)
0.0500 (B)
0.100 (C)
3.20
(D)
12.5
59. If 2.00 L of 0.600 M hydrochloric acid, HCl, and 3.00 L of 0.400 M hydrochloric acid are mixed, what is the
concentration of the resulting solution?
(A)
2.40 M (B)
l.20 M (C)
0.480 M
(D)
0.200 M
60. What is the molarity when 250 mL of a 3.0 M solution is diluted to one liter?
(A)
0.75 M (B)
1.2 M (C)
3.0 M (D)
7.5 M
61. What volume of concentrated sulfuric acid, 18.0 M H2SO4, is needed to make 2.00 L of a 1.00 M solution?
(A)
18.0 mL (B)
36.0 mL (C)
98.0 mL (D)
111 mL
62. How many grams of sucrose must be used to make 400 mL of 0.500 M sucrose solution?
Molar Mass
sucrose
(A)
34.2 g (B)
342. g·mol–1
42.7 g (C)
68.4 g (D)
137 g
63. What is the molarity of 100 mL of solution containing 1.01 g of potassium nitrate, KNO3?
(A)
1.00 M
(C)
0.100 M
(B)
0.00100 M
(D)
10.0 M
64. What mass of solid calcium chloride, CaCl2, is dissolved in 1000 g of water to prepare a 0.400 m solution?
Atomic Molar Masses
Ca
Cl
(A)
4.40 g (B)
40.1 g·mol–1
35.5 g·mol–1
14.8 g (C)
44.4 g (D)
55.5 g (E)
111 g
65. Five different solutions were prepared by dissolving 0.1 mol of each of these materials in one liter of water. Which
solution has the lowest freezing point?
(A)
K2SO4 (B)
H2SO4 (C)
Na3PO4 (D)
HCl
(E)
NaOH
66. One mole of the nonelectrolyte ethylene glycol is dissolved in 500 g of water. What is the freezing point of the
solution?
Freezing Point Depression Constant
Kf for water = 1.86 °C·m–1
(A)
–0.93 °C
(D)
–3.72 °C
(B)
–1.86 °C
(E)
–5.58 °C
(C)
–2.79 °C
67. What is the boiling point of the solution formed by dissolving 0.25 mol of a nonvolatile, nonelectrolyte in
250 g of water at one atmosphere pressure?
Boiling Point Elevation Constant
Kb for water = 0.52 °C·m–1
(A)
100.00° C
(D)
100.78° C
(B)
100.26° C
(E)
101.04° C
(C)
100.52° C
68. What is the ideal freezing point of a 0.100 m NaCl solution?
Freezing Point Depression Constant
Kf for water = 1.86 °C·m–1
(A)
0.372 °C
(C)
–0.186 °C
(B)
0.186 °C
(D)
–0.372 °C
UNIT 14 THERMOCHEMISTRY
69. The characteristic of a compound that is closely related to its heat of formation is its
(A)
density.
(D)
solubility.
(B)
stability.
(E)
boiling point.
(C)
volatility.
70. In an exothermic reaction the temperature of a 100–g water bath is raised 5 °C. How many joules does the water
absorb?
Specific heat capacity of water
4.19 J·g–1·°C–1
(A)
21 J
(B)
84 J
(C)
419 J
(D)
2090 J
71. How much heat is needed to vaporize one mole of H2O (liquid)?
H2(g) + 1/2O2(g)  H2O(l) + 285.9 kJ
H2(g) + 1/2O2(g)  H2O(g) + 242.0 kJ
(A)
2.24 kJ
(D)
285.9 kJ
(B)
43.9 kJ
(E)
527.9 kJ
(C)
242.0 kJ
72. Note the equation:
2Fe(s) + 3/2O2(g)  Fe2O3(s) H = –840 kJ·mol–1 Fe2O3
If 0.100 mol of iron reacts, how much heat is liberated?
(A)
42.0 kJ
(D)
420 kJ
(B)
84.0 kJ
(E)
840 kJ
(C)
210 kJ
73. Consider the equation:
2Al(s) + Fe2O3(s)  2Fe(s) + Al2O3(s) + 840 kJ
How many grams of aluminum react to produce 84 kJ of heat?
Atomic Molar Mass
27 g·mol–1
Al
(A)
2.7 g
(E)
54. g
(B)
5.4 g
(C)
9.0 g
(D)
27. g
74. Consider the equations:
C(s) + O2(g)  CO2(g)
H = –393.7 kJ·mol–1
CO(g) + 1/2O2(g)  CO2(g) H = –283.1 kJ·mol–1
From this information, calculate H of the equation
C(s) + 1/2O2(g)  CO(g)
75.
(A)
–110.6 kJ·mol–1 (C)
–393.7 kJ·mol–1
(B)
–172.5 kJ·mol–1 (D)
–566.2 kJ·mol–1
A table of heats (enthalpies) of formation is given.
Compound
H2S(g)
O2(g)
H2O(l)
SO2(g)
Hf (kJ·mol–1)
–21
0
–285
–297
H, for this equation?
2H2S(g) + 3O2(g)  2H2O(l) + 2SO2(g)
(A)
–1122 kJ
(C)
+561 kJ
(B)
–603 kJ
(D)
+1122 kJ
76. According to their heats of formation, the most stable of these compounds is
(A)
HI
Hf = –24.7 kJ·mol–1
(B)
H2S
Hf = +22.2 kJ·mol–1
(C)
HBr
Hf = +36.0 kJ·mol–1
(D)
HCl
Hf = +92.1 kJ·mol–1
(E)
HF
Hf = +268.7 kJ·mol–1
77. Which pair of changes insures that a chemical system undergoes a spontaneous reaction?
(A)
a decrease in enthalpy and entropy
(B)
an increase in enthalpy and entropy
(C)
an increase in enthalpy with entropy constant
(D)
an increase in enthalpy and a decrease in entropy
(E)
a decrease in enthalpy and an increase in entropy
78. In which system does randomness decrease?
(A)
ice melting
(B)
solid iodine subliming
(C)
methane gas crystallizing
(D)
salt dissolving in water
(E)
liquid alcohol evaporating
79. Which forward reaction shows an increase in entropy (disorder)?
(A)
CaCO3(s)  CaO(s) + CO2(g)
(B)
2H2(g) + O2(g)  2H2O(l)
(C)
H2(g) + CuO(s)  H2O(l) + Cu(s)
(D)
HCl(g) + NH3(g)  NH4Cl(s)
80. In which state does a sample of benzene have the lowest entropy?
(A)
crystalline benzene at 5.5 °C
(B)
liquid benzene at 5.5 °C
(C)
benzene vapor at 5.5 °C
(D)
a mixture of benzene vapor and air at 5.5 °C
UNIT 15 REACTION KINETICS
81. This potential energy diagram shows that the reaction A + B  C is
A+ B
x
C
Re action Coordinate 
(A)
slow.
(D)
endothermic.
(B)
rapid.
(E)
at equilibrium.
(C)
exothermic.
82. For the reaction
A+BC+D
the figure is the potential–energy diagram
3
1
C+ D
2
4
A+ B
Re action coordinate 
What interval represents the net energy change for this reaction?
(A)
1
(B)
2
(C)
3
(D)
4
83. Which arrow on this diagram represents the heat of reaction?
C
A
B
D
Re action Coordinate 
(A)
A
(B)
B
(C)
C
(D)
D
84. A particular exothermic reaction occurs spontaneously. Which diagram fits this reaction?
(A)
Re action path 
(C)
Re action path 
(B)
Re action path 
(D)
Re action path 
85. What is the heat of reaction, H, for the reaction A  B?
100
80
60
40
20
0
(A)
0 kJ·mol–1
(B)
–20 kJ·mol–1
(C)
(D)
Re action Coordinate 
–40 kJ·mol–1
–80 kJ·mol–1
86. Which best explains how catalysts increase the rate of a chemical reaction?
(A)
They reduce the amount of product.
(B)
They increase the amount of product.
(C)
They reduce the amount of reactants.
(D)
They raise the temperature of the reaction.
(E)
They reduce the activation energy of the reaction.
87. Consider the energy diagram for the reaction A B
100
80
B
60
A
40
20
0
Reaction Coordinate 
Which diagram represents reaction A B using a catalyst?
100
100
80
80
B
A
60
60
B
A
40
40
20
20
0
0
Re
action
Coordinate

(A)
(C) Re action Coordinate 
A
100
100
80
80
B
60
60
A
40
40
20
20
B
0
0
(B) Re action Coordinate  (D) Re action Coordinate 
88. In the reaction mechanism for the decomposition of formic acid, HCOOH,
HCOOH(l) + H+(aq)  HCOOH2 +(aq)
HCOOH2 +(aq)  HCO+(aq) + H2O(l)
HCO+(aq)  CO(g) + H+(aq)
which species acts as a catalyst?
(A)
H+(aq)
(C)
H2O(l)
(B)
CO(l)
(D)
HCOOH2+(aq)
89. On this kinetic energy distribution diagram, in which region can all collisions result in a chemical reaction?
Activation Ene rgy, E
A
B
C D
Kine tic Ene rgy 
(A)
A only
(C)
A, B, and C
(B)
C only
(D)
D only
90. Why does flour burn slowly when in a pile, but rapidly when blown into the air?
(A)
Dispersing the particles allows more energy to be released.
(B)
Dispersed particles have a greater surface area in contact with the air.
(C)
The H of the dispersed particles is greater.
(D)
Air circulating around the particles distributes heat more evenly.
91. Which is the rate–determining step in this hypothetical reaction mechanism?
A
step 1
B
step 2
C
step 3
D
step 4
E
Species Being Formed Rate of its Formation
B
C
D
E
0.0020 mol/hour per mole of A
0.030 mol/hour per mole of B
0.011 mol/hour per mole of C
0.42 mol/hour per mole of D
(A)
step 1 (B)
step 2 (C)
step 3 (D)
step 4
92. A reaction mechanism has several steps. The rate of the overall reaction is equal to
(A)
the rate of the fastest step.
(B)
the rate of the slowest step.
(C)
the average of the rates of the steps.
(D)
the difference between the rate of the fastest step and the rate of the slowest step.
93. Generally an increase of ten degrees Celsius doubles the rate of reaction between gases. What is the explanation for
this increase in reaction rate?
(A)
The pressure is doubled.
(B)
The concentration of the reactants is doubled.
(C)
The average kinetic energy of the molecules is doubled.
(D)
The number of intermolecuiar collisions per unit of time is doubled.
(E)
The number of particles with an energy above a minimum activation energy is doubled.
94. The reaction A + B 
 C + D follows the energy path shown below. What is the activation energy for the reverse
reaction?
80
70
60
50
40
30
20
10
0
C+D
A+ B
Reaction Coordinate
(A)
60 kJ·mol–1
(D)
20 kJ·mol–1
(B)
50 kJ·mol–1
(E)
10 kJ·mol–1
(C)
30 kJ·mol–1
95. Consider the diagram for the reaction
A(g) + B(g) C(g) + D(g)
+100
+80
+60
A+ B
+40
+20
0
-20
-40
C+ D
Re action Coordinate 
What is the activation energy for this reaction?
(A)
+20 kJ·mol–1
(C)
+60 kJ·mol–1
(B)
+40 kJ·mol–1
(D)
–60 kJ·mol–1
96. Consider this reaction at 500 °C:
4HBr(g) + O2(g) 
 2H2O(g) + 2Br2(g)
158 kJ
4HBr
+O
276 kJ
2H O
+ 2Br
Re action Coordinate 
What is the activation energy for the reverse reaction?
(A)
118 kJ (B)
276 kJ (C)
UNIT 16 EQUILIBRIUM
97.
UNIT 17 ACID/BASE CHEMISTRY
UNIT 18 ELECTROCHEMISTRY
158 kJ (D)
434 kJ
Answer Sheet 2nd semester review:
UNIT 5—GAS LAWS
1.
2.
3.
4.
5.
D
E
C
A
A
6. B
7. B
8. C
9. C
10. A
11.
12.
13.
14.
15.
E
E
B
A
C
16.
17.
18.
19.
20.
A
D
D
B
A
21.
22.
23.
24.
25.
C
B
C
A
D
26.
27.
28.
29.
30.
C
C
D
A
C
31.
32.
33.
34.
A
A
E
B
56.
57.
58.
59.
60.
C
D
A
C
A
61.
62.
63.
64.
65.
D
C
C
C
C
66. D
67. C
68. D
UNIT 6 SOLUTIONS/CONDENSED STATE OF MATTER
35.
36.
37.
38.
39.
40.
A
B
E
C
B
E
41.
42.
43.
44.
45.
C
D
C
B
B
46.
47.
48.
49.
50.
C
C
C
C
D
51.
52.
53.
54.
55.
B
B
D
C
D
UNIT 14 THERMOCHEMISTRY
69. B
70. D
71. B
72. A
73. B
74. A
75. A
76. E
77. E
78. C
79. A
80. A
87. C
88. A
89. D
90. B
91. A
92. B
93. E
94. D
UNIT 15 REACTION KINETICS
81. C
82. D
83. B
84. B
85. C
86. E
95. C
96. D

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