Download Chapter 6: Thermochemistry

1. Radiant 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.
Ans: C
Category: Easy
Section: 6.1
2. 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.
Ans: B
Category: Easy
Section: 6.1
3. 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.
Ans: A
Category: Easy
Section: 6.1
4. Potential 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.
Ans: D
Category: Easy
Section: 6.1
5. 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.
Ans: D
Category: Medium
Section: 6.2
6. An endothermic reaction causes the surroundings to
A) warm up.
D) decrease in temperature.
B) become acidic.
E) release CO2.
C) condense.
Ans: D
Category: Easy
Section: 6.2
Page 110
Chapter 6: Thermochemistry
7. An exothermic reaction causes the surroundings to
A) warm up.
D) decrease its temperature.
B) become acidic.
E) release CO2.
C) expand.
Ans: A
Category: Easy
Section: 6.2
8. Copper metal has a specific heat of 0.385 J/g·°C. Calculate the amount of heat required to
raise the temperature of 22.8 g of Cu from 20.0°C to 875°C.
A) 1.97  10–5 J
B) 1.0  10–2 J
C) 329 J
D) 7.51 kJ
E) 10.5 kJ
Ans: D
Category: Medium
Section: 6.5
9. Calculate the amount of heat necessary to raise the temperature of 12.0 g of water from
15.4°C to 93.0°C. The specific heat of water = 4.18 J/g·°C.
A) 0.027 J
B) 324 J
C) 389 J
D) 931 J
E) 3,890 J
Ans: E
Category: Medium
Section: 6.5
10. How much heat is required to raise the temperature of 2,500 g of water from 27°C to
72°C? The specific heat of water is 4.184 J/g·°C.
A) 0.19 kJ
B) 10. kJ
C) 280 kJ
D) 470 kJ
E) 750 kJ
Ans: D
Category: Medium
Section: 6.5
11. A beaker contains 115 g of ethanol at 18.2°C. If the ethanol absorbs 1125 J of heat
without losing 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
E) 36.4°C
Ans: D
Category: Medium
Section: 6.5
12. How many degrees of temperature rise will occur when a 25.0 g block of aluminum
absorbs 10.0 kJ of heat? The specific heat of Al is 0.900 J/g·°C.
A) 0.44°C
B) 22.5°C
C) 225°C
D) 360°C
E) 444°C
Ans: E
Category: Medium
Section: 6.5
13. If 325 g of water at 4.2°C absorbs 12.28 kJ, what is the final temperature of the water?
The specific heat of water is 4.184 J/g·°C.
A) 4.21°C
B) 4.8°C
C) 9.0°C
D) 13.2°C
E) 2,938°C
Ans: D
Category: Medium
Section: 6.5
14. A glass containing 200. g of H2O at 20°C was placed in a refrigerator. The water loses
11.7 kJ as it cools to a constant temperature. What is its new temperature? The specific
heat of water is 4.184 J/g·°C.
A) 0.013°C
B) 4°C
C) 6°C
D) 14°C
E) 34°C
Ans: C
Category: Medium
Section: 6.5
Page 111
Chapter 6: Thermochemistry
15. A piece of copper with a mass of 218 g has a heat capacity of 83.9 J/°C. What is the
specific heat of copper?
A) 0.385 J/g·°C
D) 1.32 J/g·°C
4
B) 1.83  10 J/g·°C
E) 24.5 J/g·°C
C) 2.60 J/g·°C
Ans: A
Category: Easy
Section: 6.5
16. 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
D) 39.0 kJ/mol·°C
B) 0.129 J/mol·°C
E) 197 J/mol·°C
C) 25.4 J/mol·°C
Ans: C
Category: Easy
Section: 6.5
17. 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.
E) cannot be predicted.
Ans: B
Category: Medium
Section: 6.5
18. When 0.7521 g of benzoic acid was burned in a calorimeter containing 1,000. g of water,
a temperature rise of 3.60°C was observed. What is the heat capacity of the bomb
calorimeter, excluding the water? The heat of combustion of benzoic acid is –26.42
kJ/g.
A) 15.87 kJ/°C
D) 1.34 kJ/°C
B) 4.18 kJ/°C
E) 752.1 kJ/°C
C) 5.52 kJ/°C
Ans: D
Category: Medium
Section: 6.5
19. 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) 32.9 kJ/°C
B) 7.8 kJ/°C
C) 3.64 kJ/°C
D) 1.76 kJ/°C
E)
15.3 kJ/°C
Ans: C
Category: Medium
Section: 6.5
Page 112
Chapter 6: Thermochemistry
20. Which of the following processes is endothermic?
A) O2(g) + 2H2(g)  2H2O(g)
B) H2O(g)  H2O(l)
C) 3O2(g) + 2CH3OH(g)  2CO2(g) + 2H2O(g)
D) H2O(s)  H2O(l)
Ans: D
Category: Medium
Section: 6.4
21. A 100. mL sample of 0.200 M aqueous hydrochloric acid is added to 100. mL of 0.200 M
aqueous 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
D) –1.96 kJ/mol
B) 1.96 kJ/mol
E) –154 kJ/mol
C) 485 kJ/mol
Ans: E
Category: Difficult
Section: 6.5
22. 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
D) 106 kJ/mol
B) –24.8 kJ/mol
E) –602 kJ/mol
C) 435 kJ/mol
Ans: E
Category: Difficult
Section: 6.5
23. To which one of the following reactions occurring at 25°C does the symbol
H°f[H2SO4(l)] refer?
A) 2H(g) + S(g) + 4O(g)  H2SO4(l)
D) H2SO4(l)  2H(g) + S(s) + 4O(g)
B) H2(g) + S(g) + 2O2(g)  H2SO4(l)
E) H2(g) + S(s) + 2O2(g)  H2SO4(l)
C) H2SO4(l)  H2(g) + S(s) + 2O2(g)
Ans: E
Category: Medium
Section: 6.6
24. To which one of the following reactions occurring at 25°C does the symbol
H°f[HNO3(l)] refer?
A) H(g) + N(g) + O3(g)  HNO3(l)
B) (1/2)H2(g) + (1/2)N2(g) + (3/2)O2(g)  HNO3(l)
C) HNO3(l)  (1/2)H2(g) + (1/2)N2(g) + (3/2)O2(g)
D) HNO3(l)  H(g) + N(g) + 3O(g)
E) H2(g) + N2(g) + O3(g)  HNO3(l)
Ans: B
Category: Medium
Section: 6.6
Page 113
Chapter 6: Thermochemistry
25. When 0.560 g of Na(s) reacts with excess F2(g) to form NaF(s), 13.8 kJ of heat is evolved
at standard-state conditions. What is the standard enthalpy of formation (H°f) of
NaF(s)?
A) 24.8 kJ/mol
D) –7.8 kJ/mol
B) 570 kJ/mol
E) -570 kJ/mol
C) –24.8 kJ/mol
Ans: E
Category: Medium
Section: 6.6
26. When 18.5 g of HgO(s) is decomposed to form Hg(l) and O2(g), 7.75 kJ of heat is
absorbed at standard-state conditions. What is the standard enthalpy of formation
(H°f) of HgO(s)?
A) –90.7 kJ/mol
D) 27.9 kJ/mol
B) –7.75 kJ/mol
E) 143 kJ/mol
C) 0.419 kJ/mol
Ans: A
Category: Medium
Section: 6.6
27. Ethanol undergoes combustion in oxygen to produce carbon dioxide gas and liquid water.
The standard heat of combustion of ethanol, C2H5OH(l), is –1366.8 kJ/mol. Given that
H°f[CO2(g)] = –393.5 kJ/mol and H°f[H2O(l)] = –285.8 kJ/mol, what is the standard
enthalpy of formation of ethanol?
A) 3,010 kJ/mol
D) 687.6 kJ/mol
B) –687.6 kJ/mol
E) 1,367 kJ/mol
C) –277.6 kJ/mol
Ans: C
Category: Difficult
Section: 6.6
28. Find the standard enthalpy of formation of ethylene, C2H4(g), given the following data:
heat of combustion of C2H4(g) = –1411 kJ/mol; H°f[CO2(g)] = –393.5 kJ/mol;
H°f[H2O(l)] = –285.8 kJ/mol.
A) 52 kJ/mol
D) 1.41  103 kJ/mol
B) 87 kJ/mol
E) 2.77  103 kJ/mol
C) 731 kJ/mol
Ans: A
Category: Difficult
Section: 6.6
29. Octane (C8H18) undergoes combustion according to the following thermochemical
equation:
2C8H18(l) + 25O2(g)  16CO2(g) + 18H2O(l)
H°rxn = –11,020 kJ/mol.
Given that H°f[CO2(g)] = –393.5 kJ/mol and H°f[H2O(l)] = –285.8 kJ/mol, calculate
the standard enthalpy of formation of octane.
A) –210 kJ/mol
D) –420 kJ/mol
B) –11,230 kJ/mol
E) 420 kJ/mol
C) 22,040 kJ/mol
Ans: A
Category: Medium
Section: 6.6
Page 114
Chapter 6: Thermochemistry
30. Glycine, C2H5O2N, is important for biological energy. The combustion reaction of
glycine is given by the equation
4C2H5O2N(s) + 9O2(g)  8CO2(g) + 10H2O(l) + 2N2(g)
H°rxn = –3857 kJ/mol
Given that H°f[CO2(g)] = –393.5 kJ/mol and H°f[H2O(l)] = –285.8 kJ/mol, calculate
the enthalpy of formation of glycine.
A) –537.2 kJ/mol
D) –3,178 kJ/mol
B) –268.2 kJ/mol
E) –964 kJ/mol
C) 2,149 kJ/mol
Ans: A
Category: Medium
Section: 6.6
31. Styrene, C8H8, is one of the substances used in the production of synthetic rubber.
When styrene burns in oxygen to form carbon dioxide and liquid water under
standard-state conditions at 25°C, 42.62 kJ are released per gram of styrene. Find the
standard enthalpy of formation of styrene at 25°C.
(Given: H°f[CO2(g)] = –393.5 kJ/mol, H°f[H2O(l)] = –285.8 kJ/mol, H°f[H2O(g)] =
–241.8 kJ/mol)
A) 323.8 kJ/mol
D) ~636.7 kJ/mol
B) ~4249 kJ/mol
E) 147.8 kJ/mol
C) ~8730 kJ/mol
Ans: E
Category: Difficult
Section: 6.6
32. Given 2Al(s) + (3/2)O2(g)  Al2O3(s), H°f = –1,670 kJ/mol for Al2O3 (s).
Determine H° for the reaction 2Al2O3(s)  4Al(s) + 3O2(g).
A) 3,340 kJ/mol
D) –1,670 kJ/mol
B) 1,670 kJ/mol
E) –835 kJ/mol
C) –3,340 kJ/mol
Ans: A
Category: Easy
Section: 6.6
33. Calculate the standard enthalpy of formation of liquid methanol, CH3OH(l), using the
following information:
C(graph) + O2  CO2(g)
H° = –393.5 kJ/mol
H2(g) + (1/2)O2  H2O(l)
H° = –285.8 kJ/mol
CH3OH(l) + (3/2)O2(g)  CO2(g) + 2H2O(l)
H° = –726.4 kJ/mol
A)
B)
C)
Ans:
–1,691.5 kJ/mol
–238.7 kJ/mol
1691.5 kJ/mol
B
Category: Difficult
D)
E)
47.1 kJ/mol
–47.1 kJ/mol
Section: 6.6
Page 115
Chapter 6: Thermochemistry
34. Calculate the standard enthalpy change for the reaction
2C8H18(l) + 17O2(g)  16CO(g) + 18H2O(l).
Given:
2C8H18(l) + 25O2(g) 16CO2(g) + 18H2O(l)
H° = –11,020 kJ/mol
2CO(g) + O2(g)  2CO2(g)
H° = –566.0 kJ/mol
A) 10,450 kJ/mol
D) –6,492 kJ/mol
B) 6,492 kJ/mol
E) –10.450 kJ/mol
C) 15,550 kJ/mol
Ans: D
Category: Medium
Section: 6.6
35. During volcanic eruptions, hydrogen sulfide gas is given off and oxidized by air
according to the following chemical equation:
2H2S(g) + 3O2(g)  2SO2(g) + 2H2O(g)
Calculate the standard enthalpy change for the above reaction given:
3S(s) + 2H2O(g)  2H2S(g) + SO2(g)
H° = 146.9 kJ/mol
S(s) + O2(g)  SO2(g)
H° = –296.4 kJ/mol
A)
B)
C)
Ans:
–1036.1 kJ/mol
–742.3 kJ/mol
–149.5 kJ/mol
A
Category: Medium
D)
E)
443.3 kJ/mol
742.3 kJ/mol
Section: 6.6
36. Calculate the standard enthalpy change for the reaction
2C8H18(l) + 21O2(g)  8CO(g) + 8CO2(g) + 18H2O(l).
Given:
2C8H18(l) + 25O2(g)  16CO2(g) + 18H2O(l)
H° = –11,020 kJ/mol
2CO(g) + O2(g)  2CO2(g)
H° = –566.0
kJ/mol
A) 1.0454  104 kJ/mol
D) –6,492 kJ/mol
B) –8,756 kJ/mol
E) –1.0454  104 kJ/mol
4
C) 1.1586  10 kJ/mol
Ans: B
Category: Medium
Section: 6.6
37. Given the thermochemical equation 2SO2 + O2  2SO3, H°rxn = –198 kJ/mol,
what is the standard enthalpy change for the decomposition of one mole of SO3?
A) 198 kJ/mol
D) 396 kJ/mol
B) –99 kJ/mol
E) –198 kJ/mol
C) 99 kJ/mol
Ans: C
Category: Medium
Section: 6.6
Page 116
Chapter 6: Thermochemistry
38. Given H2(g) + (1/2)O2(g)  H2O(l), H° = –286 kJ/mol, determine the standard enthalpy
change for the reaction 2H2O(l)  2H2(g) + O2(g).
A) H° = –286 kJ/mol
D) H° = +572 kJ/mol
B) H° = +286 kJ/mol
E) H° = –143 kJ/mol
C) H° = –572 kJ/mol
Ans: D
Category: Easy
Section: 6.6
39. Pentaborane B5H9(s) burns vigorously in O2 to give B2O3(s) and H2O(l). Calculate H°rxn
for the combustion of 1 mol of B5H9.
H°f[B2O3(s)] = –1,273.5 kJ/mol
H°f[B5H9(s)] = 73.2 kJ/mol
H°f[H2O(l)] = –285.8 kJ/mol
A) –1,2735 kJ/mol
D) –9,086 kJ/mol
B) –4,543 kJ/mol
E) –8,448 kJ/mol
C) –18,170 kJ/mol
Ans: B
Category: Difficult
Section: 6.6
40. For the reaction
C(graphite) + O2(g)  CO2(g)
H° = –393 kJ/mol
how many grams of C(graphite) must be burned to release 275 kJ of heat?
A) 22.3 g
B) 0.70 g
C) 12.0 g
D) 17.1 g
E) 8.40 g
Ans: E
Category: Medium
Section: 6.4
41. The combustion of butane produces heat according to the equation
2C4H10(g) + 13O2(g)  8CO2(g) + 10H2O(l)
H°rxn = –5,314 kJ/mol
What is the heat of combustion per gram of butane?
A) –32.5 kJ/g
D) –2,656 kJ/g
B) –45.7 kJ/g
E) –15,440 kJ/g
C) –91.5 kJ/g
Ans: B
Category: Medium
Section: 6.4
42. The combustion of octane produces heat according to the equation
2C8H18(l) + 25O2(g)  16CO2(g) + 18H2O(l)
H°rxn= –11,020 kJ/mol
What is the heat of combustion per gram of octane?
A) –5,510 kJ/g
D) –193 kJ/g
B) –96.5 kJ/g
E) –6.292  105 kJ/g
C) –48.2 kJ/g
Ans: C
Category: Medium
Section: 6.4
43. The combustion of butane produces heat according to the equation
2C4H10(g) + 13O2(g)  8CO2(g) + 10H2O(l)
H°rxn= –5,314 kJ/mol
How many grams of butane must be burned to release 1.00  104 kJ of heat?
A) 30.9 g
B) 61.8 g
C) 109 g
D) 153 g
E) 219 g
Ans: E
Category: Medium
Section: 6.4
Page 117
Chapter 6: Thermochemistry
44. The combustion of butane produces heat according to the equation
2C4H10(g) + 13O2(g)  8CO2(g) + 10H2O(l)
H°rxn= –5,314 kJ/mol
How many grams of CO2 are produced per 1.00  104 kJ of heat released?
A) 23.4 g
B) 44.0 g
C) 82.3 g
D) 187 g
E) 662 g
Ans: E
Category: Medium
Section: 6.4
45. Given that CaO(s) + H2O(l)  Ca(OH)2(s), H°rxn = –64.8 kJ/mol, how many grams of
CaO must react in order to liberate 525 kJ of heat?
A) 6.92 g
B) 56.1 g
C) 455 g
D) 606 g
E) 3.40  104 g
Ans: C
Category: Medium
Section: 6.4
46. The combustion of pentane produces heat according to the equation
C5H12(l) + 8O2(g)  5CO2(g) + 6H2O(l)
H°rxn= –3,510 kJ/mol
How many grams of CO2 are produced per 2.50  103 kJ of heat released?
A) 0.0809 g
B) 3.56 g
C) 31.3 g
D) 157 g
E) 309 g
Ans: D
Category: Medium
Section: 6.4
47. 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)
H°rxn= –890.4 kJ/mol
3
A) 1.4  10 g
D) 2.2  104 g
B) 3.6  105 g
E) 1.4  104 g
–4
C) 7.1  10 g
Ans: B
Category: Medium
Section: 6.4
48. Given the thermochemical equation 2SO2(g) + O2(g)  2SO3(g), H°rxn= –198 kJ/mol,
how much heat is evolved when 600. g of SO2 is burned?
A) 5.46  10–2 kJ
D) 59,400 kJ
B) 928 kJ
E) 3.71  103 kJ
3
C) 1.85  10 kJ
Ans: B
Category: Medium
Section: 6.4
49. Determine the heat given off to the surroundings when 9.0 g of aluminum reacts
according to the equation 2Al + Fe2O3  Al2O3 + 2Fe, H°rxn= –849 kJ/mol.
A) 7.6  103 kJ
D) 5.6  102 kJ
B) 2.8  102 kJ
E) 2.5  103 kJ
2
C) 1.4  10 kJ
Ans: C
Category: Medium
Section: 6.4
50. Find the heat absorbed from the surroundings when 15 g of O2 reacts according to the
equation O + O2  O3, H°rxn= –103 kJ/mol.
A) 4.6  10–3 kJ
B) 48 kJ
C) 96 kJ
D) 32 kJ
E) 110 kJ
Ans: B
Category: Medium
Section: 6.4
Page 118
Chapter 6: Thermochemistry
51. Ethanol (C2H5OH) burns according to the equation
C2H5OH(l) + 3O2(g)  2CO2(g) + 3H2O(l), H°rxn = –1367 kJ/mol.
How much heat is released when 35.0 g of ethanol is burned?
A) 1,797 kJ
B) 1,367 kJ
C) 9.61  10–4 kJ
D) 4.78  104 kJ
1,040 kJ
Ans: E
Category: Medium
Section: 6.4
E)
52. Methanol (CH3OH) burns according to the equation
2CH3OH(l) + 3O2(g)  2CO2(g) + 4H2O(l), H°rxn = –1454 kJ/mol.
How much heat, in kilojoules, is given off when 75.0 g of methanol is burned?
A) 727 kJ
D) 1.70  10–3 kJ
B) 3.22  103 kJ
E) 3.41  103 kJ
C) 1.45  103 kJ
Ans: D
Category: Medium
Section: 6.4
53. Calcium oxide and water react in an exothermic reaction:
CaO(s) + H2O(l)  Ca(OH)2(s)
H°rxn = –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
E) 555 kJ
Ans: B
Category: Medium
Section: 6.4
54. Solid sodium peroxide (Na2O2) reacts with liquid water yielding aqueous sodium
hydroxide and oxygen gas. How much heat is released when 250.0 L of oxygen gas is
produced from the reaction of sodium peroxide and water if the reaction is carried out in
an open container at 1.000 atm pressure and 25°C?
(Given: H°f[Na2O2(s)] = –510.9 kJ/mol; H°f[NaOH(aq)] = –469.2 kJ/mol;
H°f[H2O(l)] = –285.8 kJ/mol)
A) 35,400 kJ
B) 1740 kJ
C) 141.7 kJ
D) 3330 kJ
E) 2900 kJ
Ans: E
Category: Difficult
Section: 6.6
55. At 25°C, the standard enthalpy of formation of KCl(s) is –435.87 kJ/mol. When one
mole of KCl(s) is formed by reacting potassium vapor and chlorine gas at 25°C, the
standard enthalpy of reaction is –525.86 kJ/mol. Find H° for the sublimation of
potassium, K(s)  K(g), at 25°C.
A) –345.88 kJ/mol
D) 89.99 kJ/mol
B) 45.00 kJ/mol
E) –525.86 kJ/mol
C) 345.88 kJ/mol
Ans: D
Category: Medium
Section: 6.6
Page 119
Chapter 6: Thermochemistry
56. At 25°C, the standard enthalpy of formation of anhydrous sodium carbonate is –1130.9
kJ/mol, whereas the standard enthalpy of formation of sodium carbonate monohydrate is
–1430.1 kJ/mol. Determine H° at 25°C for the reaction
Na2CO3(s) + H2O(l)  Na2CO3·H2O(s).
(Given: H°f[H2O(l)] = –285.8 kJ/mol)
A) –13.4 kJ/mol
D) –299.2 kJ/mol
B) –285.8 kJ/mol
E) –156.3 kJ/mol
C) –585.0 kJ/mol
Ans: A
Category: Medium
Section: 6.6
57. 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.
Ans: A
Category: Easy
Section: 6.3
58. 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 mol of gas phase K+ ions and Cl– ions.
A) 718 kJ
B) 684 kJ
C) –684 kJ
D) –718 kJ
E) None of these.
Ans: C
Category: Medium
Section: 6.7
59. 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 mol of gas phase Li+ ions and Cl– ions.
A) 791 kJ
B) 865 kJ
C) –865 kJ
D) –791 kJ
E) None of these.
Ans: C
Category: Medium
Section: 6.7
60. The total heat of hydration of 1 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) 37 kJ/mol
D) –37 kJ/mol
B) 1,693 kJ/mol
E) None of these.
C) –1,693 kJ/mol
Ans: D
Category: Medium
Section: 6.7
61. 10.1 g CaO is dropped into a styrofoam coffee cup containing 157 g H2O at 18.0°C.
If the following 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)
H°rxn = –64.8 kJ/mol
A) 18.02°C
B) 35.8°C
C) 311°C
D) 42.2°C
E) 117°C
Ans: B
Category: Medium
Section: 6.5
Page 120
Chapter 6: Thermochemistry
62. The enthalpy change when a strong acid is neutralized by strong base is –56.1 kJ/mol.
If 135 mL of 0.450 M HI at 23.15°C is mixed with 145 mL of 0.500 M NaOH, also at
23.15°C, what will the maximum temperature reached by the resulting solution? (Assume
that there is no heat loss to the container, that the specific heat of the final solution is 4.18
J/g·°C, and that the density of the final solution is that of water.)
A) 26.06°C
B) 29.19°C
C) 32.35°C
D) 20.24°C
E) 36.57°C
Ans: A
Category: Difficult
Section: 6.5
63. The enthalpy change when a strong acid is neutralized by strong base is –56.1 kJ/mol.
If 12.0 mL of 6.00 M HBr at 21.30°C is mixed with 300. mL of 0.250 M NaOH, also at
21.30°C, what will the maximum temperature reached by the resulting solution? (Assume
that there is no heat loss to the container, that the specific heat of the final solution is 4.18
J/g·°C, and that the density of the final solution is that of water.)
A) 18.20°C
B) 24.53°C
C) 101.8°C
D) 24.40°C
E) 34.25°C
Ans: D
Category: Difficult
Section: 6.5
64. 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) 6,190 kJ
B) 6.19 kJ
C) 61.1 J
D) 5.66 kJ
E) 518 J
Ans: B
Category: Medium
Section: 6.3
65. 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) 1.01  104 J
B) –180 J
C) 1.81  104 J
D) –1.81  104 J
180 J
Ans: C
Category: Medium
Section: 6.3
E)
66. 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
D) w = –2.52 kJ
B) w = +24.9 kJ
E) w = –19.3 kJ
C) w = 0
Ans: E
Category: Medium
Section: 6.3
Page 121
Chapter 6: Thermochemistry
67. 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?
Ans: A
Category: Medium
Section: 6.3
68. Which of the following processes always results in an increase in the energy of a system?
A) The system loses heat and does work on the surroundings.
B) The system gains heat and does work on the surroundings.
C) The system loses heat and has work done on it by the surroundings.
D) The system gains heat and has work done on it by the surroundings.
E) None of these is always true.
Ans: D
Category: Medium
Section: 6.3
69. For which of these reactions will the difference between H° and E° be the greatest?
A) 2H2O2(l)  2H2O(l) + O2(g)
B) CaCO3(s)  CaO(s) +CO2(g)
C) NO(g) + O3(g)  NO2(g) + O2(g)
D) 2C2H6(g) + 7O2(g)  4CO2(g) + 6H2O(l)
E) 4NH3(g) + 5O2(g)  4NO(g) + 6H2O(g)
Ans: D
Category: Medium
Section: 6.4
70. For which of these reactions will the difference between H° and E° be the smallest?
A) N2(g) + 3H2(g)  2NH3(g)
B) 4PH3(g)  P4(g) + 6H2(g)
C) H2(g) + Cl2(g)  2HCl(g)
D) CO2(g) + 2H2O(l)  CH4(g) + 2O2(g)
E) P4(s) + 10Cl2(g)  4PCl5(s)
Ans: C
Category: Medium
Section: 6.4
Page 122
Chapter 6: Thermochemistry
71. At 25°C, the following heats of reaction are known:
2ClF(g) + O2(g)  Cl2O(g) + F2O(g)
H°rxn = 167.4 kJ/mol
2ClF3(g) + 2O2(g)  Cl2O(g) + 3F2O(g)
H°rxn = 341.4 kJ/mol
2F2(g) + O2(g)  2F2O(g)
H°rxn = –43.4 kJ/mol
At the same temperature, use Hess's law to calculate H°rxn for the reaction:
ClF(g) + F2(g)  ClF3(g)
A) –217.5 kJ/mol
D) –108.7 kJ/mol
B) –130.2 kJ/mol
E) 465.4 kJ/mol
C) 217.5 kJ/mol
Ans: D
Category: Medium
Section: 6.6
72. The bond enthalpy of the Br–Cl bond is equal to H° for the reaction
BrCl(g)  Br(g) + Cl(g).
Use the following data to find the bond enthalpy of the Br–Cl bond.
Br2(l)  Br2(g)
H° = 30.91 kJ/mol
Br2(g)  2Br(g)
H° = 192.9 kJ/mol
Cl2(g)  2Cl(g)
H° = 243.4 kJ/mol
Br2(l) + Cl2(g)  2BrCl(g) H° = 29.2 kJ/mol
A)
B)
C)
Ans:
219.0 kJ/mol
203.5 kJ/mol
14.6 kJ/mol
A
Category: Medium
D)
E)
438.0 kJ/mol
407.0 kJ/mol
Section: 6.6
73. The heat of solution of ammonium nitrate is 26.2 kJ/mol. If a 5.368 g sample of
NH4NO3 is added 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) 14.3°C
B) 20.8°C
C) –7.7°C
D) 25.6°C
E) 21.4°C
Ans: E
Category: Difficult
Section: 6.5
74. The heat of solution of ammonium chloride is 15.2 kJ/mol. If a 6.134 g sample of
NH4Cl is added to 65.0 mL of water in a calorimeter at 24.5°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 = 365. J/°C.)
A) 27.1°C
B) 18.6°C
C) 19.7°C
D) 21.9°C
E) 30.4°C
Ans: D
Category: Difficult
Section: 6.5
75. Aluminum oxide can be reduced to aluminum metal using carbon, the other reaction
product being carbon monoxide. Determine the enthalpy change when 12.5 g of
aluminum is produced by this method. [H°f(carbon monoxide) = –110.5 kJ/mol;
H°f(aluminum oxide) = –1669.8 kJ/mol]
A) 725 kJ
B) 697 kJ
C) 310 kJ
D) 361 kJ
E) 1504 kJ
Ans: C
Category: Difficult
Section: 6.6
Page 123
Chapter 6: Thermochemistry
76. Ozone (O3) in the atmosphere can be converted to oxygen gas by reaction with nitric
oxide (NO). Nitrogen dioxide is also produced in the reaction. What is the enthalpy
change when 8.50L of ozone at a pressure of 1.00 atm and 25°C reacts with 12.00 L of
nitric oxide at the same initial pressure and temperature? [H°f(NO) = 90.4 kJ/mol;
H°f(NO2) = 33.85 kJ/mol; H°f(O3) = 142.2 kJ/mol]
A) –69.2 kJ
B) –19.7 kJ
C) –1690 kJ
D) –97.6 kJ
E) –167 kJ
Ans: A
Category: Difficult
Section: 6.6
77. Define specific heat.
Ans: The amount of heat required to raise the temperature of one gram of a substance by
one degree Celsius.
Category: Easy
Section: 6.5
78. How many grams of ethylene (C2H4) would have to be burned to produce 450 kJ of heat?
C2H4(g) + 3O2(g)  2CO2(g) + H2O(l)
H°rxn = –1411 kJ/mol
Ans: 8.95 g
Category: Medium
Section: 6.4
79. Calculate the enthalpy of reaction for H2(g) + C2H4(g)  C2H6(g).
[H°f(C2H4(g)) = 52.3 kJ/mol; H°f(C2H6(g)) = –84.7 kJ/mol]
Ans: –137 kJ/mol
Category: Medium
Section: 6.6
80. The enthalpy of combustion of acetylene C2H2 is described by
C2H2(g) + (5/2)O2(g)  2CO2(g) + H2O(l)
H°rxn= –1299 kJ/mol
Calculate the enthalpy of formation of acetylene, given the following enthalpies of
formation
H°f[CO2(g)] = –393.5 kJ/mol
H°f[H2O(l)] = –285.8 kJ/mol
Ans: 226 kJ/mol
Category: Medium
Section: 6.6
81. Given the following H° values,
H2(g) + 1 2 O2(g)  H2O(l)
H°f = –285.8 kJ/mol
H2O2(l)  H2(g) + O2(g)
H°rxn = 187.6 kJ/mol
calculate H°rxn for the reaction H2O2(l)  H2O(l) +
Ans: –98.2 kJ/mol
Category: Medium
Section: 6.6
1
2
O2(g),
82. The heat of solution of calcium chloride CaCl2 is –82.8 kJ/mol, and the combined heats
of hydration of 1 mole of gaseous calcium ions and 2 mole of gaseous chloride ions is
–2327 kJ. What is the lattice energy of calcium chloride?
Ans: 2,244 kJ/mol
Category: Medium
Section: 6.7
Page 124
Chapter 6: Thermochemistry
83. The heat of solution of NH4NO3 is 26.2 kJ/mol. Is heat evolved or absorbed when a
solution of NH4NO3 is diluted by addition of more water?
Ans: Absorbed
Category: Easy
Section: 6.7
84. A 26.2 g piece of copper metal is heated from 21.5°C to 201.6°C. Calculate the amount
of heat absorbed by the metal. The specific heat of Cu is 0.385 J/g·°C.
Ans: 1,820 J
Category: Medium
Section: 6.5
85. A 0.1946 g piece of magnesium metal is burned in a constant-volume calorimeter that has
a heat capacity of 1349 J/°C. The calorimeter contains 500. g of water and the
temperature rise is 1.40°C. Calculate the heat of combustion of magnesium metal in
kJ/g, given that the specific heat of water = 4.184 J/g·°C.
Ans: 24.8 kJ/g
Category: Medium
Section: 6.5
86. A 0.3423 g sample of pentane, C5H12, was burned in a bomb calorimeter. The
temperature of the calorimeter and the 1.000 kg of water contained therein rose from
20.22°C to 22.82°C. The heat capacity of the calorimeter is 2.21 kJ/°C. The heat
capacity of water = 4.184 J/g·°C. How much heat was given off during combustion of
the sample of pentane?
Ans: 16.6 kJ
Category: Medium
Section: 6.5
87. A 0.3423 g sample of pentane, C5H12, was burned in a bomb calorimeter. The
temperature of the calorimeter and the 1.000 kg of water contained therein rose from
20.22°C to 22.82°C. The heat capacity of the calorimeter is 2.21 kJ/°C. The heat
capacity of water = 4.184 J/g·°C. What is the heat of combustion, in kilojoules, per
gram of pentane?
Ans: 48.6 kJ/g
Category: Medium
Section: 6.5
88. A 0.3423 g sample of pentane, C5H12, was burned in a bomb calorimeter. The
temperature of the calorimeter and the 1.000 kg of water contained therein rose from
20.22°C to 22.82°C. The heat capacity of the calorimeter is 2.21 kJ/°C. The heat
capacity of water = 4.184 J/g·°C. What is the heat of combustion, in megajoules (MJ),
per mole of pentane?
Ans: 3.50 MJ/mol
Category: Medium
Section: 6.5
Page 125
Chapter 6: Thermochemistry
89. The heat of combustion of propane, C3H8, 2220 kJ/mol. The specific heat of copper is
0.385 J/g°C. How many grams of propane must be burned to raise the temperature of a
10.0 kg block of copper from 25.0°C to 65.0°C, assuming none of the heat is lost to the
surroundings
Ans: 3.06 g
Category: Medium
Section: 6.5
90. The residential rate for natural gas is about $15 per thousand cubic foot. Burning one
cubic foot of natural gas releases about 1080 kJ of heat. How much would it cost to heat
the water in a 25,000 gallon swimming pool from 52°F to 78°F, assuming all of the heat
from burning the natural gas went towards warming the water? (1 gal = 3.785 L; the
specific heat of water = 4.184 J/g·°C)
Ans: $79
Category: Difficult
Section: 6.5
91. The heat of neutralization of HCl by NaOH is H°rxn = –56.2 kJ/mol. How much heat is
released when 125 mL of 1.750 M HCl is mixed with 195 mL of 0.667 M NaOH?
Ans: 7.31 kJ
Category: Difficult
Section: 6.5
92. The heat released when one mole of water is formed from the elements is 1,198 kJ. An
experiment was conducted that permitted water to form in this manner, and the heat was
contained in 2.0 liters of water. The water temperature before the reaction was 34.5°C,
and after the reaction it had risen to 52.0°C. How many moles of water were formed?
(The specific heat of water is 4.184 J/g·°C.)
Ans: 0.12 mole
Category: Medium
Section: 6.5
93. When an automobile engine starts, the metal parts immediately begin to absorb heat
released during the combustion of gasoline. How much heat will be absorbed by a 165
kg iron engine block as the temperature rises from 15.7°C to 95.7°C? (The specific heat
of iron is 0.489 J/g·°C.)
Ans: 6,450 kJ
Category: Medium
Section: 6.5
94. The value of H°rxn for the following reaction is –6535 kJ/mol.
2C6H6(l) + 15O2(g)  12CO2(g) + 6H2O(g)
How many kilojoules of heat will be evolved during the combustion of 16.0 g of C6H6(l)?
Ans: 669 kJ
Category: Medium
Section: 6.4
Page 126
Chapter 6: Thermochemistry
95. What would be the standard enthalpy change for the reaction of one mole of H2(g) with
one mole of Cl2(g) to produce two moles of HCl(g) at standard state conditions?
[H°f (HCl(g))= –92.3 kJ/mol]
Ans: –185 kJ
Category: Medium
Section: 6.6
96. What is the standard enthalpy of formation of H2(g) at 25°C?
Ans: 0 kJ/mol
Category: Easy
Section: 6.6
97. Find H°rxn for the reaction
CH4(g) + 2O2(g)  CO2(g) + 2H2O(l).
[H°f (CH4(g)) = –74.8 kJ/mol; H°f (CO2(g)) = –393.5 kJ/mol; H°f (H2O(l)) = –285.5
kJ/mol]
Ans: -889.7 kJ/mol
Category: Medium
Section: 6.6
98. Find H°rxn for the reaction
2Ag2S(s) + 2H2O(l)  4Ag(s) + 2H2S(g) + O2(g).
[H°f (Ag2S(s)) = –32.6 kJ/mol; H°f (H2S(g)) = –20.5 kJ/mol; H°f (H2O(l)) = –285.5
kJ/mol]
Ans: 595.2 kJ/mol
Category: Medium
Section: 6.6
99. Find H°rxn for the reaction
2Na(s) + 2H2O(l)  2NaOH(aq) + 2H2(g).
[H°f (NaOH(aq)) = –426.8 kJ/mol; H°f (H2O(l)) = –285.5 kJ/mol]
Ans: –282.6 kJ
Category: Medium
Section: 6.6
100. The specific heat of silver is 0.235 J/g·°C. How many joules of heat are required to heat
a 75 g silver spoon from 20°C to 35°C?
Ans: 260 J
Category: Easy
Section: 6.5
101. At body temperature 2,404 joules of energy are required to evaporate 1.00 g of water.
After vigorous exercise, a person feels chilly because the body is giving up heat to
evaporate the perspiration. A typical person perspires 25 mL of water after 20. minutes of
exercise. How much body heat is this person using to evaporate this water?
Ans: 6.0  104 J
Category: Easy
Section: 6.4
Page 127
Chapter 6: Thermochemistry
102. The combustion of one mole of benzene, C6H6, in oxygen liberates 3268 kJ of heat. The
products of the reaction are carbon dioxide and water. How much heat is given off
when 183 g of oxygen are reacted with excess benzene?
Ans: 2490 kJ
Category: Difficult
Section: 6.4
103. A feverish student weighing 75 kilograms was immersed in 400. kg of water at 4.0°C to
try to reduce the fever. The student's body temperature dropped from 40.0°C to 37.0°C.
Assuming the specific heat of the student to be 3.77 J/g·°C, what was the final
temperature of the water?
Ans: 4.5°C
Category: Difficult
Section: 6.5
104. The specific heats of water and iron are 4.184 and 0.444 J/g°C, respectively. When
equal masses of water and iron both absorb the same amount of heat, the temperature
increase of the water will be 5.42 times greater than that of the iron.
Ans: True
Category: Medium
Section: 6.5
105. Chemical reactions in a bomb calorimeter occur at constant pressure.
Ans: True
Category: Easy
Section: 6.5
106. If 2Mg(s) + O2(g)  2MgO(s), H° = –1203.6 kJ/mol.
For Mg(s) + (1/2)O2(g)  MgO(s), the enthalpy change is H = –601.8 kJ/mol.
Ans: True
Category: Easy
Section: 6.6
107. The heat capacity of 20.0 g of water is 83.7 J/°C.
Ans: True
Category: Medium
Section: 6.5
108. The work done on the surroundings by the expansion of a gas is w = –PV.
Ans: True
Category: Easy
Section: 6.3
109. The heat absorbed by a system at constant pressure is equal to E + PV.
Ans: True
Category: Easy
Section: 6.4
110. In an endothermic process, heat is absorbed by the system.
Ans: True
Category: Easy
Section: 6.2
111. A home aquarium is an example of an open system.
Ans: True
Category: Easy
Section: 6.2
112. The heat of hydration (Hhydr) of ions is always endothermic.
Ans: False
Category: Medium
Section: 6.7
Page 128
Chapter 6: Thermochemistry
1.
In the following diagram of a wave
A)
frequency
B)
amplitude
C)
D)
(a) is amplitude and (b) is
(a) is frequency and (b) is amplitude E)
(a) is wavelength and (b) is
(a) is wavelength and (b) is frequency
Ans: E
Category: Easy
Section: 7.1
2.
A)
B)
3.
(a) is amplitude and (b) is wavelength
As the frequency of an electromagnetic wave increases
its speed must increase.
C)
its amplitude must increase.
its wavelength must increase. D)
its energy must increase.
Ans: D
Category: Easy
Section: 7.2
14 –1
What is the wavelength of radiation that has a frequency of 5.39
s ? (c =
m/s)
–3
nm
B) 556 nm
C) 618 nm
D) 6180 nm
E)
23
nm
Ans: B
Category: Easy
Section: 7.1
8
4.
A)
B)
C)
14
22
–6
2
8
m D)
nm E)
5
m
Ans: D
Category: Easy
m
m
Section: 7.1
Page 129
s –1?
Chapter 6: Thermochemistry
5.
A)
B)
C)
Calculate the frequency of visible light having a wavelength of 486 nm.
14
–15
/s D)
/s
6
–7
2.06
/s E)
/s
14
/s
Ans: C
Category: Easy
Section: 7.1
6.
A)
B)
C)
Calculate the frequency of visible light having a wavelength of 686 nm.
14
–15
/s D)
/s
5
–6
/s E)
/s
14
6.17
/s
Ans: A
Category: Easy
Section: 7.1
7.
What is the energy in joules of one photon of microwave radiation with a
–34
8
A)
B)
C)
–43
–10
J D)
J
9
J E)
J
–24
J
Ans: C
Category: Medium
–33
Section: 7.2
8.
What is the energy in joules of a mole of photons associated with visible light of
wavelength 486 nm?
–16
A)
J D)
12.4 kJ
–25
B)
J E)
246 kJ
–4
C)
J
Ans: E
Category: Medium
Section: 7.2
9.
What is the energy in joules of a mole of photons associated with red light of
2
nm?
5
–43
J
D) 12.4 kJ
42
J
Ans: B
Category: Medium
Section: 7.2
10.
What is the binding energy (in J/mol or kJ/mol) of an electron in a metal whose
14
/s?
17
99.7 kJ/mol D)
kJ/mol
–19
–6
1.66
J/mol E)
J/mol
–43
J/mol
Ans: A
Category: Medium
Section: 7.2
E)
A)
B)
C)
11.
A)
B)
C)
D)
E)
Complete this sentence: Atoms emit visible and ultraviolet light
as electrons jump from lower energy levels to higher levels.
as the atoms condense from a gas to a liquid.
as electrons jump from higher energy levels to lower levels.
as they are heated and the solid melts to form a liquid.
as the electrons move about the atom within an orbit.
Page 130
Chapter 6: Thermochemistry
Ans: C
Category: Easy
Section: 7.3
12.
Calculate the energy, in joules, required to excite a hydrogen atom by causing an
electronic transition from the n = 1 to the n = 4 principal energy level. Recall that the energy
levels of the H atom are given by
–18
En = –2.18
J(1/n2)
–29
–17
A)
J D)
J
5
–18
B)
J E)
J
–18
C)
J
Ans: C
Category: Medium
Section: 7.3
13.
Calculate the wavelength, in nanometers, of the light emitted by a hydrogen atom
when its electron falls from the n = 7 to the n = 4 principal energy level. Recall that the energy
levels of the H atom are given by
–18
En = –
J(1/n2)
–20
14
A)
nm
D)
nm
–6
3
B)
nm
E)
nm
–20
C)
nm
Ans: E
Category: Medium
Section: 7.3
14.
Calculate the frequency of the light emitted by a hydrogen atom during a
transition of its electron from the n = 6 to the n = 3 principal energy level. Recall that for
–18
hydrogen En = –
J(1/n2).
15
–19
A)
/s D)
/s
13
14
B)
/s E)
/s
14
C)
/s
Ans: E
Category: Medium
Section: 7.3
15.
Calculate the frequency of the light emitted by a hydrogen atom during a
transition of its electron from the n = 4 to the n = 1 principal energy level. Recall that for
–18
hydrogen En = –
J(1/n2)
15
–51
A)
/s D)
/s
8
14
B)
/s E)
/s
14
C)
/s
Ans: A
Category: Medium
Section: 7.3
16.
Calculate the wavelength of the light emitted by a hydrogen atom during a
transition of its electron from the n = 4 to the n = 1 principal energy level. Recall that for
–18
hydrogen En = –
J(1/n2)
A) 97.2 nm
B) 82.6 nm
C) 365 nm
D) 0.612 nm
E) 6.8
–18
nm
Ans: A
Category: Medium
Section: 7.3
17.
The second line of the Balmer series occurs at a wavelength of 486.1 nm. What
is the energy difference between the initial and final levels of the hydrogen atom in this emission
process?
Page 131
Chapter 6: Thermochemistry
A)
B)
C)
–28
J D)
J
–19
–48
J E)
J
–22
J
Ans: B
Category: Medium
18
Section: 7.3
18.
A proton is roughly 1800 times more massive than an electron. If a proton and an
electron are traveling at the same speed,
A)
the wavelength of the photon will be about 1800 times longer than the wavelength
of the electron.
B)
the wavelength of the photon will be about 1800 times longer than the
wavelength of the electron.
C)
the wavelength of the photon will be roughly equal to the wavelength of the
electron.
D)
the wavelength of the electron will be about 1800 times longer than the
wavelength of the photon.
E)
the wavelength of the electron will be about 1800 times longer than the
wavelength of the photon.
Ans: E
Category: Medium
Section: 7.3
19.
A photon is roughly 1800 times more massive than an electron. If a proton and an
electron have the same kinetic energy,
A)
the wavelength of the photon will be about 1800 times longer than the wavelength
of the electron.
B)
the wavelength of the photon will be about 1800 times longer than the
wavelength of the electron.
C)
the wavelength of the photon will be roughly equal to the wavelength of the
electron.
D)
the wavelength of the electron will be about 1800 times longer than the
wavelength of the photon.
E)
the wavelength of the electron will be about 1800 times longer than the
wavelength of the photon.
Ans: D
Category: Difficult
Section: 7.3
20.
If a hydrogen atom and a helium atom are traveling at the same speed,
A)
the wavelength of the hydrogen atom will be about 4 times longer than the
wavelength of the helium atom.
B)
the wavelength of the hydrogen atom will be about 2 times longer than the
wavelength of the helium.
C)
the wavelength of the hydrogen atom will be roughly equal to the wavelength of
the helium atom.
D)
the wavelength of the helium atom will be about 2 times longer than the
wavelength of the hydrogen atom.
E)
the wavelength of the helium atom will be about 4 times longer than the
wavelength of the hydrogen atom.
Ans: A
Category: Medium
Section: 7.3
Page 132
Chapter 6: Thermochemistry
21.
If a hydrogen atom and a helium atom have the same kinetic energy,
A)
the wavelength of the hydrogen atom will be about 4 times longer than the
wavelength of the helium atom.
B)
the wavelength of the hydrogen atom will be about 2 times longer than the
wavelength of the helium.
C)
the wavelength of the hydrogen atom will be roughly equal to the wavelength of
the helium atom.
D)
the wavelength of the helium atom will be about 2 times longer than the
wavelength of the hydrogen atom.
E)
the wavelength of the helium atom will be about 4 times longer than the
wavelength of the hydrogen atom.
Ans: B
Category: Difficult
Section: 7.3
22.
In an electron microscope, electrons are accelerated to great velocities.
3
kilometers per
–28
g.
–13
Ans: D
5
–7
Category: Medium
–10
m
Section: 7.4
23.
Calculate the wavelength associated with a 20Ne+ ion moving at a velocity of 2.0
m/s. The atomic mass of Ne-20 is 19.992 amu.
–13
12
A)
m D)
m
–16
–13
B)
m E)
cm
–18
C)
m
Ans: A
Category: Medium
Section: 7.4
24.
Calculate the wavelength of a neutron that has a velocity of 250 cm/s. (The
–24
–34
10–4 m
Ans: D
25.
Category: Medium
Section: 7.4
A common way of initiating certain chemical reactions with light involves the
2
kJ/mol, what is the longest wavelength of light that will produce free chlorine atoms in solution?
A) 246.3 nm
B) 465.2 nm
C) 349.3 nm
D) 698.6 nm
E)
492.6 nm
Ans: E
Category: Difficult
Section: 7.2
26.
The longest wavelength of light that causes electrons to be ejected from the
surface of a copper plate is 243 nm. What is the maximum velocity of the electrons ejected
when light of wavelength 200. nm shines on a copper plate?
6
4
A)
m/s
D)
m/s
5
6
B)
m/s
E)
m/s
4
C)
m/s
Page 133
Chapter 6: Thermochemistry
Ans: B
Category: Difficult
Section: 7.2
27.
When photons with a wavelength of 310. nm strike a magnesium plate, the
5
m/s. Calculate the binding energy of
electrons to the magnesium surface.
A)
386 kJ/mol
D)
321 kJ/mol
B)
419 kJ/mol
E)
353 kJ/mol
C)
32.7 kJ/mol
Ans: E
Category: Difficult
Section: 7.2
28.
Electrons can be used to probe the arrangement of atoms on a solid surface if the
wavelength of the electrons is comparable with the spacing between the atoms. Which of the
following electron velocities would be appropriate for use in this application if the atoms are
separated by 0.320 nm?
6
6
A)
m/s
D)
m/s
3
3
B)
m/s
E)
m/s
8
C)
m/s
Ans: A
Category: Difficult
Section: 7.4
18
29.
nm. If melting ice to water at 0°C requires 6.01 kJ/mol, what is the fewest number of laser
pulses need to melt 10.0 g of ice?
A) 3830
B) 3340
C) 38300
D) 2120
E) 212
Ans: D
Category: Difficult
Section: 7.2
30.
Which one of the following sets of quantum numbers is not possible?
Ans:
B
Category: Medium
Section: 7.6
31.
Which one of the following sets of quantum numbers is not possible?
Ans:
B
Category: Medium
Section: 7.6
Page 134
Chapter 6: Thermochemistry
32.
What is the maximum number of electrons in an atom that can have the following
set of quantum numbers?
n=4
l= 3
ml = –2
ms = +1/2
A) 0
B) 1
C) 2
D) 6
E) 10
Ans: B
Category: Easy
Section: 7.8
33.
A possible set of quantum numbers for the last electron added to complete an
atom of gallium (Ga) in its ground state is
Ans:
C
Category: Medium
Section: 7.8
34.
A possible set of quantum numbers for the last electron added to complete an
atom of germanium (Ge) in its ground state is
Ans:
35.
C
Category: Medium
Section: 7.8
Electrons in an orbital with l = 3 are in a/an
A) d orbital.
B) f orbital.
C) g orbital.
D) p orbital.
E)
s
orbital.
Ans: B
36.
Category: Easy
Section: 7.6
The number of orbitals in a d subshell is
A) 1
B) 2
C) 3
D) 5
E) 7
Ans: D
Category: Easy
Section: 7.6
37.
The maximum number of electrons that can occupy an energy level described by
the principal quantum number, n, is
A) n
B) n + 1
C) 2n
D) 2n2
E) n2
Ans: D
Category: Medium
Section: 7.8
38.
How many orbitals are allowed in a subshell if the angular momentum quantum
number for electrons in that subshell is 3?
A) 1
B) 3
C) 5
D) 7
E) 9
Ans: D
Category: Medium
Section: 7.6
Page 135
Chapter 6: Thermochemistry
39.
statement of
A)
B)
C)
"No two electrons in an atom can have the same four quantum numbers" is a
the Pauli exclusion principle. D)
de Broglie's relation.
Bohr's equation.
E)
Dalton's atomic theory.
Hund's rule.
Ans: A
Category: Easy
Section: 7.8
40.
The orbital diagram for a ground-state nitrogen atom is
Ans:
A
Category: Medium
Section: 7.8
41.
The orbital diagram for a ground-state oxygen atom is
Ans:
D
Category: Medium
Section: 7.8
42.
The orbital diagram for a ground state carbon atom is
Ans:
D
Page 136
Chapter 6: Thermochemistry
Category: Medium
Section: 7.8
43.
Which ground-state atom has an electron configuration described by the following
orbital diagram?
A) phosphorus
B) germanium
C) selenium
E) none of these
Ans: C
Category: Medium
Section: 7.9
D) tellurium
44.
Which ground-state atom has an electron configuration described by the following
orbital diagram?
A) antimony
B) germanium
Ans: E
Category: Medium
C) indium
Section: 7.9
D) lead
E)
tin
45.
Which ground-state atom has an electron configuration described by the following
orbital diagram?
A) phosphorus
B)
nitrogen
C)
arsenic
D) vanadium
none of these
Ans: A
Category: Medium
Section: 7.9
46.
How many unpaired electrons does a ground-state atom of sulfur have?
A) 0
B) 1
C) 2
D) 3
E) 4
Ans: C
Category: Medium
Section: 7.9
47.
A)
B)
C)
A ground-state atom of arsenic has
no unpaired electrons. D)
three unpaired electrons.
one unpaired electron. E)
four unpaired electrons.
two unpaired electrons.
Ans: D
Category: Medium
Section: 7.9
48.
Which element has the following ground-state electron configuration?
1s22s22p63s2
A) Na
B) Mg
C) Al
D) Si
E) Ne
Ans: B
Category: Medium
Section: 7.9
49.
Which element has the following ground-state electron configuration?
[Kr]5s24d105p3
A) Sn
B) Sb
C) Pb
D) Bi
E) Te
Ans: B
Category: Medium
Section: 7.9
Page 137
E)
Chapter 6: Thermochemistry
50.
Which element has the following ground-state electron configuration?
[Ar]4s23d104p5
A) aresnic
B) bromine
C) iodine
D) selenium
E)
tellerium
Ans: B
Category: Medium
Section: 7.9
51.
Which element has the following ground-state electron configuration?
[Kr]5s14d5
A) Mn
B) Mo
C) Nb
D) Re
E) Tc
Ans: B
Category: Medium
Section: 7.9
52.
Which element has the following ground-state electron configuration?
[Kr]5s24d105p2
A) Sn
B) Sb
C) Pb
D) Ge
E) Te
Ans: A
Category: Medium
Section: 7.9
53.
A)
B)
C)
The electron configuration of a ground-state Co atom is
[Ar]4s23d7
D)
[Ar]4s13d5
2 2
6 2 9
1s 2s 2p 3s 3d
E)
[Ar]4s24d7
[Ne]3s23d7
Ans: A
Category: Medium
Section: 7.9
54.
The electron configuration of a ground-state vanadium atom is
A) [Ar]4s24d3
B) [Ar]4s24p3
C) [Ar]4s23d3
D) [Ar]3d5
Ans: C
Category: Medium
Section: 7.9
55.
The electron configuration of a ground-state copper atom is
A) [Ar]4s24d4
B) [Ar]4s24p63d3
C) [Ar]4s23d9
E) [Ar]4s13d10
Ans: E
Category: Medium
D) [Ar]3d9
Section: 7.9
56.
A)
B)
C)
The ground-state electron configuration for an atom of indium is
[Kr]5s24p64d5 D)
[Kr]5s25p64d5
[Ar]4s23d104p1 E)
[Kr]5s24d105p1
2
6 5
[Ar]4s 4p 3d
Ans: E
Category: Medium
Section: 7.9
57.
Which of the following is the ground-state electron configuration of a calcium
atom?
A) [Ne]3s2
B) [Ne]3s23p6
C) [Ar]4s13d1
D) [Ar]4s2
2
[Ar]3d
Ans: D
Category: Medium
Section: 7.9
58.
How many electrons are there in the 2nd principal energy level (n = 2) of a
phosphorus atom?
A) 3
B) 5
C) 6
D) 8
E) 10
Page 138
E)
Chapter 6: Thermochemistry
Ans: D
Category: Medium
Section: 7.9
59.
How many electrons are there in the 3rd principal energy level (n = 3) of a
phosphorus atom?
A) 3
B) 5.
C) 6
D) 8
E) 10
Ans: B
Category: Medium
Section: 7.9
60.
A)
B)
C)
A ground-state atom of manganese has ___ unpaired electrons and is _____.
0, diamagnetic D)
5, paramagnetic
2, diamagnetic E)
7, paramagnetic
3, paramagnetic
Ans: D
Category: Medium
Section: 7.9
61.
A)
B)
C)
A ground-state atom of vanadium has ___ unpaired electrons and is _____.
0, diamagnetic D)
5, paramagnetic
2, diamagnetic E)
4, diamagnetic
3, paramagnetic
Ans: C
Category: Medium
Section: 7.9
62.
A)
B)
C)
A ground-state atom of iron has ___ unpaired electrons and is _____.
0, diamagnetic D)
5, paramagnetic
6, diamagnetic E)
4, paramagnetic
3, paramagnetic
Ans: E
Category: Medium
Section: 7.9
63.
A)
B)
C)
Transition metal elements have atoms or ions with partially filled
s subshells. D)
f subshells.
p subshells. E)
g subshells.
d subshells.
Ans: C
Category: Easy
Section: 7.9
64.
A)
B)
C)
Lanthanide (or rare earth elements) have atoms or ions with partially filled
s subshells. D)
f subshells.
p subshells. E)
g subshells.
d subshells.
Ans: D
Category: Easy
Section: 7.9
65.
Which choice lists two elements with ground-state electron configurations that are
well known exceptions to the Aufbau principle?
A) Cu and C
B) Cr and Cu
C) Cs and Cl
D) Rb and Co
E) Fe and Co
Ans: B
Category: Medium
Section: 7.9
66.
A ground-state chromium atom has how many unpaired electrons?
A) 1
B) 2
C) 4
D) 5
E) 6
Ans: E
Category: Medium
Section: 7.9
Page 139
Chapter 6: Thermochemistry
67.
Which of the following is the electron configuration of an excited state of an
oxygen atom?
A) 1s22s22p4
B) 1s22s22p5
C) 1s22s22p33s1
D) 1s22s22p6
E) 1s22s22p3
Ans: C
Category: Medium
Section: 7.9
68.
Which of the following is the electron configuration of an excited state of an iron
atom?
A) [Ar]4s23d7
E) [Ar]4s13d5
Ans: D
69.
copper atom?
A)
B)
C)
B) [Ar]4s23d6
Category: Medium
C) [Ar]4s23d8
D) [Ar]4s13d7
Section: 7.9
Which of the following is the electron configuration of an excited state of a
[Ar]4s23d9
D)
[Ar]4s23d8
1
10
[Ar]4s 3d
E)
[Ar]4s03d10
[Ar]4s13d8
Ans: A
Category: Medium
Section: 7.9
70.
The ground-state electron configuration of Cr, Mo, and Ag are exceptions to the
Aufbau principle. Which of the following is the electron configuration for Mo?
A) [Kr]5s14d5
B) [Kr]5s24d4
C) [Xe]6s25d4
D) [Ar]4s24d4
2 6
E) [Kr]5s 4d
Ans: A
Category: Medium
Section: 7.9
71.
How many electrons in a ground-state tellurium atom are in orbitals labeled by l =
1?
A) 4
Ans: E
72.
B) 10
C) 12
Category: Medium
D) 16
E) 22
Section: 7.9
How many electrons in a ground-state cadmium atom are in orbitals labeled by ml
= –1?
A) 2
Ans: B
73.
B) 10
C) 12
Category: Medium
D) 18
E) 36
Section: 7.9
Which of the following ground-state atoms is diamagnetic?
A) Ca
B) As
C) Cu
D) Fe
E) none of these
Ans: A
Category: Medium
Section: 7.9
74.
Which of the following atoms is paramagnetic both in its ground state and in all
of its excited states?
A) C
B) N
C) O
D) Ti
E) Cr
Ans: B
Category: Difficult
Section: 7.9
75.
Which of the following is diamagnetic both in its ground state and in all of its
Page 140
Chapter 6: Thermochemistry
excited states?
A) Mg
Ans: E
B) Ne
C) Cu
Category: Difficult
D) Zn
E) none of these
Section: 7.9
76.
The electron in a hydrogen atom falls from an excited energy level to the ground
state in two steps, causing the emission of photons with wavelengths of 2624 and 97.2 nm.
What is the quantum number of the initial excited energy level from which the electron falls?
A) 2
B) 3
C) 4
D) 6
E) 8
Ans: D
Category: Difficult
Section: 7.3
77.
The electron in a hydrogen atom falls from an excited energy level to the ground
state in two steps, causing the emission of photons with wavelengths of 1870 and 102.5 nm.
What is the quantum number of the initial excited energy level from which the electron falls?
A) 2
B) 3
C) 4
D) 6
E) 8
Ans: C
Category: Difficult
Section: 7.3
78.
When the electron in a hydrogen atom falls from the n = 3 excited energy level to
same wavelength would have a velocity of
3
A)
m/s
D)
7.10 m/s
6
8
B)
m/s
E)
m/s
3
C)
m/s
Ans: A
Category: Medium
Section: 7.4
79.
When the electron in a hydrogen atom falls from its first excited energy level to
the
same wavelength would have a velocity of
–7
m/s
D) 3.26 m/s
E) 5.99 m/s
Ans: D
Category: Medium
Section: 7.4
80.
Breaking the oxygen-oxygen bond in hydrogen peroxide requires 210 kJ/mol.
What is the longest wavelength of light that can cause this bond to be broken?
–4
–28
A)
m D)
m
–31
–7
B)
m E)
m
–7
C)
m
Ans: E
Category: Medium
Section: 7.2
81.
Rank the following types of electromagnetic radiation from lowest energy to
highest energy: infrared, microwave, radio waves, gamma rays, visible, and ultraviolet.
Ans: radio waves < microwaves < infrared < visible < ultraviolet < gamma rays
Category: Medium
Section: 7.1
82.
Ans:
An FM radio station broadcasts at a frequency of 101.7 MHz. Calculate the
8
m/s)
2.948 m
Page 141
Chapter 6: Thermochemistry
Category: Easy
83.
Ans:
Section: 7.1
An AM radio station broadcasts at a frequency of 1270 kHz. Calculate the
8
m/s)
236 m
Category: Medium
Section: 7.1
84.
Ans:
Write the ground state electron configuration for the selenium atom.
[Ar] 4s23d104p4
Category: Medium
Section: 7.9
85.
Ans:
Write the ground state electron configuration for the phosphorus atom.
[Ne] 3s23p3
Category: Medium
Section: 7.9
86.
Ans:
Write the ground state electron configuration for an iodine atom.
[Kr] 5s24d105p5
Category: Medium
Section: 7.9
87.
Ans:
Write the ground state electron configuration for a lead atom.
[Xe] 6s24f145d106p2
Category: Medium
Section: 7.9
88.
Ans:
Write the ground state electron configuration for Ni.
[Ar] 4s23d8
Category: Medium
Section: 7.9
89.
Ans:
Write the ground state electron configuration for Cr.
[Ar] 4s13d5
Category: Medium
Section: 7.9
90.
Ans:
Calculate the energy of a photon of light with a wavelength of 360 nm.
–19
J
Category: Medium
Section: 7.2
91.
carbon–12?
Ans:
What is the difference in the electron configuration between carbon–14 and
92.
by an atom?
Ans:
With regard to electron behavior, what happens when light is absorbed or emitted
93.
There is no difference
Category: Easy
Section: 7.8
The electrons move between orbitals.
Category: Easy
Section: 7.3
What is the total number of electrons possible in the 2p orbitals?
Page 142
Chapter 6: Thermochemistry
Ans:
6
Category: Easy
Section: 7.8
94.
Ans:
What is the total number of electrons possible in the 6s orbital?
2
Category: Easy
Section: 7.8
95.
Ans:
What is the ground-state electron configuration for chlorine?
1s22s22p63s23p5
or
[Ne]3s23p5
Category: Medium
Section: 7.9
96.
If one electron is added to the outer shell of chlorine, it would have the same
electron configuration as what element?
Ans: argon
Category: Easy
Section: 7.9
97.
Ans:
What is the electron configuration of calcium?
1s22s22p63s23p64s2
or
[Ar]4s2
Category: Medium
Section: 7.9
98.
If we take away two electrons from the outer shell of calcium, it would have the
same electron configuration as what element?
Ans: argon
Category: Easy
Section: 7.9
99.
The colors of the visible spectrum are blue, green, orange, red, violet, and yellow.
Of these colors, _______ has the most energy.
Ans: violet
Category: Easy
Section: 7.1
100. The colors of the visible spectrum are blue, green, orange, red, violet, and yellow.
Of these colors, ______ has the least energy.
Ans: red
Category: Easy
Section: 7.1
101. The colors of the visible spectrum are blue, green, orange, red, violet, and yellow.
Of these colors, _______ has the longest wavelength.
Ans: red
Category: Easy
Section: 7.1
102. The colors of the visible spectrum are blue, green, orange, red, violet, and yellow.
Of these colors, ______ has the shortest wavelength.
Ans: violet
Category: Easy
Section: 7.1
103.
What is the wavelength, in meters, of an alpha particle with a kinetic energy of
Page 143
Chapter 6: Thermochemistry
–13
Ans:
104.
–13
Ans:
–27
–15
m
Category: Medium
kg)
Section: 7.4
What is the wavelength, in meters, of an alpha particle with a kinetic energy of
–27
kg]
–15
m
Category: Medium
Section: 7.4
105. The scattering of helium atoms by a solid can be used to gain information about
the lattice of atoms, provided the wavelength of the helium atoms is comparable to the
dimensions of the lattice. What is the wavelength, in picometers, of a helium-4 atom with a
–24
kinetic energy of 0.10 eV. (mass of 4
–34
10–19
Ans: 45 pm
Category: Difficult
Section: 7.4
106.
10.0 cm/s?
Ans:
What is the wavelength of a ball bearing with a mass of 10.0 g, and a velocity of
10–22 nm
Category: Medium
Section: 7.4
107. The bonds of oxygen molecules are broken by sunlight. The minimum energy
required to break the oxygen-oxygen bond is 495 kJ/mol. What is the wavelength of sunlight
that can cause this bond breakage?
Ans: 242 nm
Category: Medium
Section: 7.2
108. A photovoltaic cell converts light into electrical energy. Suppose a certain
photovoltaic cell is only 63.5% efficient, in other words, that 63.5% of the light energy is
ultimately recovered. If the energy output of this cell is used to heat water, how many 520 nm
photons must be absorbed by the photovoltaic cell in order to heat 10.0 g of water from 20.0°C
to 30.0°?
21
Ans:
Category: Difficult
Section: 7.2
109. The Bohr model of the hydrogen atom found its greatest support in experimental
work on the photoelectric effect.
Ans: True
Category: Medium
Section: 7.3
110. An electron in a 3p orbital could have a value of 2 for its angular momentum
quantum number (l).
Ans: True
Category: Medium
Section: 7.6
111.
A neon atom in its ground state will be diamagnetic.
Ans: True
Category: Medium
Section: 7.8
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Chapter 6: Thermochemistry
112.
Each shell (principal energy level) of quantum number n contains n subshells
Ans: True
Category: Easy
Section: 7.6
113.
For all atoms of the same element, the 2s orbital is larger than the 1s orbital.
Ans: True
Category: Easy
Section: 7.7
114. According to de Broglie's equation, the wavelength associated with the motion of
a particle increases as the particle mass decreases.
Ans: True
Category: Easy
Section: 7.4
115.
The frequency of the emitted light from a cesium atom is an intensive property.
Ans: True
Category: Easy
Section: 7.2
Page 145