Chemistry & Chemical Reactions Kotz9e TB 10 PDF

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Chemistry & Chemical Reactions Chapter 10...

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Chapter 10—Gases and Their Properties MULTIPLE CHOICE 1. Which of the following would represent the greatest pressure? a. 58143 Pa b. 307 mmHg c. 11.7 psi d. 0.624 atm

e. 17.7 in Hg

ANS: C

2. A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 736 mm above the pool of mercury. What is the pressure of the atmosphere? a. 1.03 atm b. 0.646 atm c. 463 atm d. 0.968 atm e. 0.736 atm ANS: D

3. The local weather forecaster reports that the current barometric pressure is 30.4 inches of mercury. What is the current pressure in atmospheres? a. 1.02 atm b. 10.29 atm c. 1.00 atm d. 4.05 atm e. 910 atm ANS: A

4. A particular gas exerts a pressure of 637 mmHg. What is this pressure in units of bar? (1 atm = 760 mm Hg = 101.3 kPa = 1.013 bar) a. b. c. d. e.

4.78  105 bar 4.91  105 bar 645 bar 0.827 bar 0.849 bar

ANS: E

5.A physics experiment is conducted at a pressure of 14.3 kPa. What is this pressure in mmHg? (1 atm = 760 mm Hg = 101.3 kPa) a. 18.8 mmHg b. 1.88 10  2 mmHg c. 1.91 mmHg d. 107 mmHg e. 1.43 104 mmHg ANS: D

6. A particular gas exerts a pressure of 3.43 bar. What is this pressure in units of atmospheres? (1 atm = 760 mm Hg = 101.3 kPa = 1.013 bar) a. b. c. d. e.

3.48 atm 2.57  103 atm 2.64  103 atm 3.39 atm 3.43 atm

Kotz 9e

ANS: D

Chapter 10

Gases and Their Properties

Gases and Their Properties

Chapter 10

Kotz 9e

7. A particular gas exerts a pressure of 7.54  104 Pa. What is this pressure in units of atmospheres? (1 atm = 760 mm Hg = 101.3 kPa = 1.013 bar) a. b. c. d. e.

0.744 atm 7.44  109 atm 0.764 atm 0.754 atm 7.64  109 atm

ANS: A

8. It is possible to make a barometer using a liquid other than mercury. What would be the height (in meters) of a column of carbon tetrachloride at a pressure of 0.890 atm, given that 0.890 atm is equal to a 0.676 m column of mercury and the densities of mercury and carbon tetrachloride are 13.5 g/cm 3 and 1.58 g/cm3, respectively. a. 5.78 m b. 0.173 m c. 0.0792 m d. 1.07 m e. 0.936 m ANS: A

9. A flexible vessel contains 45 L of gas where the pressure is 1.4 atm. What will the volume be when the gas is compressed to a pressure of 0.82 atm, the temperature remaining constant? a. 0.013 L b. 26 L c. 45 L d. 0.049 L e. 77 L ANS: E

10. A sample of methane, CH4, occupies a volume of 202.0 mL at 25°C and exerts a pressure of 1155.0 mmHg. If the volume of the gas is allowed to expand to 690.0 mL at 298 K, what will be the pressure of the gas? a. b. c. d. e.

3950 mmHg 4030 mmHg 338.1 mmHg 0.01255 mmHg 488.0 mmHg

ANS: C

11. A flexible vessel contains 38.00 L of gas at a pressure of 2.74 atm. Under conditions of constant temperature and moles of gas, what is the volume of the gas when the pressure of the vessel is decreased by a factor of two? a. 76.0 L ANS: A

b. 19.0 L

c. 0.0132 L

d. 38 L

e. 3.80 L

Gases and Their Properties

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12. A flexible vessel is filled to a certain pressure with 67.00 L of gas. Under conditions of constant temperature and moles of gas, how does the pressure of the gas change when the volume of the gas is tripled? a. b. c. d. e.

The pressure decreases by a factor of three. The pressure decreases by a factor of four. The pressure increases by a factor of two. The pressure remains the same. The pressure decreases by a factor of two.

ANS: A

13. A gas sample is held at constant pressure. The gas occupies 3.62 L of volume when the temperature is 21.6°C. Determine the temperature at which the volume of the gas is 3.49 L. a. 295 K b. 284 K c. 20.8 K d. 557 K e. 306 K ANS: B

14. A balloon has a volume of 2.32 liters at 24.0°C. The balloon is heated to 48.0°C. Calculate the new volume of the balloon. a. 2.32 L b. 2.51 L c. 2.15 L d. 4.64 L e. 1.16 L ANS: B

15. A flexible container is charged with 30.00 L of gas at 313. Under conditions of constant pressure and moles of gas, what is the volume of the gas when the temperature is decreased by a factor of two? a. 15.0 L

b. 60.0 L

c. 0.0167 L

d. 30 L

e. 3.00 L

ANS: A

16. A certain person has a body temperature of 309 K. On a cold day, what volume of air at 278 K must this person with a lung capacity of 3.5 L breathe in to fill his lungs? a. 3.89 L b. 3.15 L c. 3.31 L d. 6.30 L e. none of these ANS: B

17. Absolute zero is the point at which a. a straight-line graph of V versus T (C) intersects the origin. b. a straight-line graph of 1/V versus P at constant T intersects the origin. c. gaseous helium liquefies. d. a straight-line graph of V versus 1/P at constant T intersects the origin. e. a straight-line graph of V versus T (K) intersects the origin. ANS: E

Gases and Their Properties

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18. Which of the following is a correct statement of Charles’s law, ? a. The volume of a gas varies proportionally with the pressure. b. The volume of a gas sample varies directly with the absolute temperature. c. All gas samples of the same volume at STP contain the same number of atoms. d. The pressure of a gas sample varies inversely with the volume. e. All gas samples of the same volume at STP contain the same number of molecules. ANS: B 19. A gas sample is heated from 20.0°C to 57.0°C and the volume is increased from 2.00 L to 4.50 L. If the initial pressure is 0.140 atm, what is the final pressure? a. 0.0477 atm b. –0.177 atm c. 0.411 atm d. 0.242 atm e. 0.0811 atm ANS: E

20. A sample of helium gas occupies 14.7 L at 23°C and 0.956 atm. What volume will it occupy at 40°C and 1.20 atm? a. 19.5 L b. 20.4 L c. 11.1 L d. 12.4 L e. 14.9 L ANS: D

21. The temperature of a specific amount of gas in a sealed container changes from 20.0°C to 40.0°C. If the volume remains constant, the pressure will change from 735 mmHg to ___. a. 735 mmHg b. 368 mmHg c. 1470 mmHg d. 688 mmHg e. 785 mmHg ANS: E

22. A 2.00-L glass soda bottle filled only with air is tightly capped at 19°C and 680.0 mmHg. If the bottle is placed in water at 81°C, what is the pressure in the bottle? a. 160 mmHg

b. 824 mmHg

c. 2900 mmHg

d. 561 mmHg

e. 422 mmHg

ANS: B

23. The volume of a sample of gas measured at 75.0°C and 1.00 atm pressure is 5.00 L. What must the final temperature be in order for the gas to have a final volume of 4.00 L at 1.00 atm pressure? a. 5.4°C

b. 60.0°C

c. –213.0°C

d. 93.8°C

e. 162.0°C

ANS: A

24. A balloon is filled with He gas to a volume of 2.10 L at 35 C. The balloon is placed in liquid nitrogen until its temperature reaches –196 C. Assuming the pressure remains constant, what is the volume of the cooled balloon? a. 0.375 L b. 0.375 L c. 0.525 L d. 0.00909 L e. 8.40 L ANS: C

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25. The pressure of 5.4 L of nitrogen gas in a flexible container is decreased to one-half its original pressure, and its absolute temperature is increased to double the original temperature. The volume is now a. 2.7 L.

b. 5.4 L.

c. 11 L.

d. 22 L.

e. 1.4 L.

ANS: D

26. You have a 30.0 L cylinder of helium at a pressure of 132 atm and a temperature of 19 C. The He is used to fill balloons to a volume of 1.80 L at 745 mm Hg and 27 C. How many balloons can be filled with He? Assume that the cylinder can provide He until its internal pressure reaches 1.00 atm (i.e., there are 131 atmospheres of usable He in the cylinder). a. 1.90  102 b. 1.06  102 c. 4.13  103 d. 7.41  103 e. 2.29  103 ANS: E 27. Equal volumes of propane, C3H8, and carbon monoxide, CO, at the same temperature and pressure have the same ____. a. chemical properties. b. number of atoms. c. average molecular speed. d. density. e. number of molecules. ANS: E 28. Which of the following concerning the behavior of ideal gases is/are true? 1. 2. 3.

Pressure is directly proportional to volume when temperature and moles of gas are held constant. Pressure is directly proportional to moles of gas when temperature and volume are held constant. Volume is inversely proportional to temperature when the pressure and moles of gas are held constant.

a. 1 only

b. 2 only

c. 3 only

d. 1 and 2 only

e. 2 and 3 only

ANS: B 29. For an ideal gas, which two variables are directly proportional to each other (if all other conditions remain constant)? 1. T and n 2. V and n 3. P and T a. 1 only ANS: E

b. 2 only

c. 3 only

d. 1 and 2

e. 2 and 3

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30. What volume of gaseous water, H 2O, has the same moles of gas as 10.0 L of xenon gas at the same temperature and pressure? a. 40.0 L b. 2.50 L c. 10.0 L d. 3.33 L e. 30.0 L ANS: C

31. A 25.0-L sample of nitrogen at 4.45 atm and 23°C is simultaneously expanded to 60.8 L and heated to 37°C. What is the new pressure of the gas? a. 2.94 atm

b. 1.92 atm

c. 212 atm

d. 326 atm

e. 1.75 atm

ANS: B

32. Gaseous chlorine is held in two separate containers at identical temperature and pressure. The volume of container 1 is 1.30 L, and it contains 6.70 mol of the gas. The volume of container 2 is 2.33 L. How many moles of the gas are in container 2? a. 12.0 mol b. 20.3 mol c. 0.452 mol d. 3.74 mol e. none of these ANS: A

33. A gas occupying a volume of 1.50 L exerts a pressure of 700 mmHg at 200°C. Which mathematical expression gives the correct pressure at 6.00 L and 400°C? a. b. c. d. e. ANS: B

34. What volume of oxygen will react with 21 mL of ethanol, assuming the gases are present at the same temperature and pressure? 2 CH3CH2OH(g) + 6 O2(g)  4 CO2(g) + 6 H2O(g) a. 7.0 mL b. 14 mL c. 21 mL d. 42 mL e. 63 mL ANS: E

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Gases and Their Properties

35. You have 49.1 g of O2 gas in a container with twice the volume as one with CO2 gas. The pressure and temperature of both containers are the same. Calculate the mass of carbon dioxide gas you have in the container. a. 0.767 g b. 67.5 g c. 3.07 g d. 33.8 g e. none of these ANS: D 36. If 0.357 g of CH4 gas is introduced into an evacuated 1.75 L flask at 25 C, what is the pressure inside the flask? (R = 0.08206 Latm/molK) a. 0.952 atm b. 0.261 atm c. 0.311 atm d. 0.419 atm e. 4.99 atm ANS: C 37. The pressure of O2 in a 15.0 L flask is 322 mm Hg at 44 C. What mass of O2 is in the flask? (R = 0.08206 Latm/molK) a. 0.244 g b. 5.80 g c. 7.82 g d. 15.2 g e. 56.3 g ANS: C 38. A 45.0 L gas cylinder contains 988 g He at 23 C. What is the pressure inside the cylinder? ( R = 0.08206 Latm/molK) a. 10.4 atm b. 41.4 atm c. 101 atm d. 133 atm e. 533 atm ANS: D 39. What is the pressure of a 59.6-L gas sample containing 3.01 mol of gas at 44.9°C? (R = 0.0821 L • atm/(K • mol), 1 atm = 760 mmHg) a. b. c. d. e.

1.41  102 mmHg 1.73  10–3 mmHg 1.32 mmHg 1.00  103 mmHg 5.77  102 mmHg

ANS: D

Gases and Their Properties

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40. What volume is occupied by 35.0 g of C2H2 at 471 mm Hg and 21 C? (R = 0.08206 Latm/molK) a. 29.0 L b. 52.3 L c. 3.74 L d. 20.1 L e. 0.0689 L ANS: B 41. What volume does 40.5 g of N2 occupy at STP? (R = 0.08206 Latm/molK) a. 64.8 L b. 1.81 L c. 32.4 L d. 50.7 L e. none of these ANS: C

42. Which of the following gases has the greatest density at 35 C and 450 mm Hg? a. CH4 b. Ar c. N2 d. Cl2 e. C3H8 ANS: D 43. Which of the following samples contains the fewest moles of gas? a. 1.00 L of CH4 at STP b. 1.00 L of Ar at –10.0°C and 1.00 atm c. 1.00 L of NH3 at 10°C and 1.00 atm d. 1.00 L of H2 at 0.0°C and 1.76 atm e. 1.00 L of HCl at 20°C and 1.00 atm ANS: E

44. The density of ethane, C2H6 (30.1 g/mol), at 32°C and 1.17 atm pressure is ___. (R = 0.08206 Latm/molK) a. 1.41 g/L

b. 17.2 g/L

c. 1.34 g/L

d. 0.711 g/L

e. 0.144 g/L

ANS: A

45. The density of H2 gas in a rigid container is 0.117 g/L at 55 C. What is the pressure of hydrogen in the flask if it is heated to 125 C? (R = 0.08206 Latm/molK) a. 0.142 atm b. 0.194 atm c. 1.56 atm d. 1.90 atm e. 3.55 atm ANS: D

Gases and Their Properties

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46. At what temperature does 742 mm Hg of CH4 gas have the same density as 742 mm Hg of O2 gas at 273 K? a. 137 K b. 146 K c. 191 K d. 275 K e. 545 K ANS: A 47. A 3.74 gram sample of a certain diatomic gas occupies a volume of 3.48-L at 1.00 atm and a temperature of 45°C. Identify this gas. (R = 0.08206 Latm/molK) a. b. c. d. e. ANS: B

48. It is found that 250. mL of a gas at STP has a mass of 0.700 g. What is the molar mass of the gas? a. 62.7 g/mol b. 2.80 g/mol c. 15.9 g/mol d. 11.2 g/mol e. 128 g/mol ANS: A

49. The density of a gas is 1.96 g/L at STP. What is its molar mass? a. 65.2 g/mol

b. 58.9 g/mol

c. 11.4 g/mol

d. 22.4 g/mol

e. 43.9 g/mol

ANS: E

50. Sodium azide decomposes rapidly to produce nitrogen gas. 2 NaN3(s)  2 Na(s) + 3 N2(g) What mass of sodium azide will inflate a 60.0 L airbag for a car to a pressure of 1.50 atm at 32 C? (R = 0.08206 Latm/molK) a. 2.40 g b. 67.2 g c. 156 g d. 234 g e. 351 g ANS: C 51. What mass of O2 is required to produce 5.00 L NO 2 at 305 K and 752 mm Hg? (R = 0.08206 Latm/molK) 2 NO(g) + O2(g)  2 NO2(g) a. 0.198 g b. 1.58 g c. 3.16 g d. 5.00 g e. 6.33 g ANS: C

Gases and Their Properties

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52. What volume of O2, measured at 24.0°C and 0.630 atm atm, will be produced by the decomposition of 3.00 g KClO3? Assume 100% yield. (R = 0.08206 Latm/molK) 2 KClO3(s)  2 KCl(s) + 3 O2(g) a. 1.42 103 mL b. 9.47 102 mL c. 1.15 102 mL d. 6.31 102 mL e. none of these ANS: A

53. What volume of

measured at STP is produced by the combustion of 6.46 g of natural gas

in excess oxygen? (R = 0.08206 Latm/molK) a. 4.51 L

b. 19.7 L

c. 9.02 L

d. 18.0 L

e. 3.23 L

ANS: D

54. Into a 2.22-liter container at 25°C are placed 1.23 moles of O 2 gas and 3.20 moles of solid C (graphite). If the carbon and oxygen react completely to form CO( g), what will be the final pressure in the container at 25°C? a. 27.1 atm b. 13.5 atm c. 2.27 atm d. 35.2 atm e. none of these ANS: A

55. The following equation represents the partial combustion of methane, CH 4. 2CH4(g) + 3O2(g)  2CO(g) + 4H2O(g) At constant temperature and pressure, what is the maximum volume of carbon monoxide that can be obtained from 3.39  102 L of methane and 1.70  102 L of oxygen? a. b. c. d. e.

5.09  102 L 3.39  102 L 1.19  103 L 1.13  102 L 6.78  102 L

ANS: D

56. Ammonia gas is synthesized according to the balanced equation below. N2(g) + 3 H2(g)  2 NH3(g) If 1.55 L N2 react with 4.92 L H2, what is the theoretical yield (in liters) of NH3? Assume that the volumes of reactants and products are measured at the same temperature and pressure. a. 1.55 L b. 3.10 L c. 3.28 L d. 4.93 L e. 6.42 L ANS: B

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Chapter 10

Gases and Their Properties

Gases and Their Properties

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57. Aqueous hydrochloric acid reacts with magnesium to produce hydrogen gas according to the balanced equation below. 2 HCl(aq) + Mg(s)  MgCl2(aq) + H2(g) If 250.0 mL of 3.00 M HCl is combined with 9.92 g Mg, what volume of hydrogen gas can be produced? Assume the temperature and pressure of the gas are 25 C and 0.988 atm, respectively. ( R = 0.08206 Latm/molK) a. 4.60 L b. 5.05 L c. 9.28 L d. 10.1 L e. 18.6 L ANS: C 58. An excess of sodium hydroxide is treated with 3.3 L of dry hydrogen chloride gas measured at STP, producing sodium chloride and water. What is the mass of sodium chloride is formed? a. 1.65 g

b. 17.2 g

c. 8.6 g

d. 14 g

e. 193 g

ANS: C

59. When 0.5000 grams of an unknown hydrocarbon, CxHy, is completely combusted with excess oxygen, 1.037 L CO2 gas and is produced at 98.3 C and 1.000 atm. What is the empirical formula of the hydrocarbon? (R = 0.08206 Latm/molK) a. CH b. CH2 c. C2H3 d. C3H5 e. C3H8 ANS: E 60. One way to isolate metals from their ores is to react the metal oxide with carbon as shown in the following reaction (M = metal):

If 34.14 g of a metal oxide reacted with excess carbon and 4.38 L of CO 2 formed at 100°C and 1.50 atm, what is the identity of the metal? a. Hg b. Mg c. Cu d. Zn e. Cd ANS: C

61. A mixture of KCl and KClO3 weighing 1.34 grams was heated; the dry O2 generated occupied 143 mL at STP. What percent by mass of the original mixture was KClO 3, which decomposes as follows: a. 38.9%

b. 58.4%

c. 87.6%

d. 10.7%

e. 23.7%

ANS: A

62. An unknown gaseous hydrocarbon contains 85.63% C. Its density is 1.524 g/L at 0.665 atm and 373 K. What is the molecular formula of the gas? ( R = 0.08206 Latm/molK) a. C2H4 b. C3H6 c. C4H8 d. C5H10 e. C6H12 ANS: D

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63. A 22.4 L high pressure reaction vessel is charged with 0.3750 mol of iron powder and 1.78 atm of oxygen gas at standard temperature. On heating, the iron and oxygen react according to the balanced reaction below. 4Fe(s) + 3O2(g)  2Fe2O3(s) After the reaction vessel returns to standard temperature, and assuming the reaction goes to completion, what pressure of oxygen remains? a. 1.50 atm

b. 1.78 atm

c. 1.28 atm

d. 0.281 atm

e. 0.00 atm

ANS: A

64. What is the total volume of gases produced at 1092 K and 1.00 atm pressure when 192 g of ammonium nitrite undergoes the following decomposition reaction? NH4NO2(s)  N2(g) + 2H2O(g) a. 8.97 101 L b. 22.4 L c. 2.69 102 L d. 6.72 101 L e. 8.07 102 L ANS: E

65. In which of the following reactions will the pressure increase upon completion of the reaction at constant temperature? a. C(s) + O2(g)  CO2(g) b. 2NO(g) + O2(g)  2NO2(g) c. C2H6O(l) + 3O2(g)  2CO2(g) + 3H2O(l) d. 4NH3(g) + 5O2(g)  4NO(g) + 6H2O(g) e. Cl2(g) + 3F2(g)  2ClF3(g) ANS: D 66. What is the volume occupied by a mixture of 0.203 mol of N2 and 0.203 mol of O2 gases at 1.16 atm and 44.7°C? a. b. c. d. e.

2.74  102 L 9.13 L 0.642 L 1.28 L 4.57 L

ANS: B

67. A vessel with a volume of 26.9 L contains 2.80 g of nitrogen gas, 0.605 g of hydrogen gas, and 79.9 g of argon gas. At 25°C, what is the pressure in the vessel? a. 75.5 atm b. 0.183 atm c. 2.55 atm d. 2.18 atm e. 58.7 atm

Kotz 9e ANS: D

Chapter 10

Gases and Their Properties

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Chapter 10

Gases and Their Properties

68. Water can be decomposed by electrolysis into hydrogen gas and oxygen gas. What mass of water must decompose to fill a 3.00 L flask to a total pressure of 2.00 atm at 298 K with a mixture hydrogen and oxygen? (R = 0.08206 Latm/molK) 2 H2O( )  2 H2(g) + O2(g) a. 1.47 g b. 2.95 g c. 4.4...