Deck 10: Gases

Question 1

What is the pressure in atmospheres exerted by a column of mercury that is 100. m high? (density of mercury = 13.5951 g/cm³, gravitational constant = 9.80665 m/s², 1 atm = 101,325 Pa = 760 torr = 760 mmHg)

A) 1.4 × 10¹⁰ atm
B) 0.013 atm
C) 0.73 atm
D) 1.37 atm
E) 132 atm

Answer 1

132 atm

Question 2

Which is not a property of a gas?

A) The density of a gaseous substance varies greatly with temperature.
B) A sample of gas assumes the shape and volume of its container.
C) Gases are highly compressible.
D) The densities of gases are much larger than those of corresponding liquids.
E) Gases form homogeneous mixtures with one another in any proportion.

Answer 2

The densities of gases are much larger than those of corresponding liquids.

Question 3

A flask containing argon gas is connected to a closed-ended mercury manometer. The closed end is under vacuum. If the mercury level in the closed arm is 230. mm above that in the arm connected to the flask, what is the argon pressure, in torr?

A) -230. torr
B) 230. torr
C) 530. torr
D) 790. torr
E) 990. torr

Answer 3

230. torr

Question 4

The pressure of sulfur dioxide in a container is 159 kPa. What is this pressure in atmospheres? (1 atm = 101,325 Pa = 760 torr)?

A) 0.209 atm
B) 0.637 atm
C) 1.57 atm
D) 21.2 atm
E) 1.59 ×10⁴ atm

Question 5

"The pressure of an ideal gas is inversely proportional to its volume at constant temperature and number of moles" is a statement of ________ law.

A) Charles's
B) Boyle's
C) Amontons's
D) Avogadro's
E) Gay-Lussac's

Question 6

"The volume of an ideal gas is directly proportional to the number of moles of the gas at constant temperature and pressure" is a statement of ________ law.

A) Charles's
B) Boyle's
C) Dalton's
D) Avogadro's
E) Gay-Lussac's

Question 7

The pressure of hydrogen sulfide gas in a container is 3.565 ×10⁴ Pa. What is this pressure in torr? (1 atm = 101,325 Pa = 760 torr)?

A) 46.91 torr
B) 267.4 torr
C) 351.8 torr
D) 3612 torr
E) 2.709 ×10⁴ torr

Question 8

What is the pressure in atmospheres exerted by a column of water that is 12.5 m high? (density of water = 1.00g/cm³; gravitational constant = 9.80665 m/s², 1 atm = 101,325 Pa = 760 torr = 760 mmHg)

A) 123 atm
B) 1.23 × 10⁵ atm
C) 0.785 atm
D) 1.21 atm
E) 1.23 × 10^-3 atm

Question 9

A sample of an ideal gas has its volume doubled while its temperature remains constant. If the original pressure was 100 torr, what is the new pressure?

A) 10 torr
B) 50 torr
C) 100 torr
D) 200 torr
E) 1000 torr

Question 10

"The volume of an ideal gas is directly proportional to its absolute temperature at constant pressure and number of moles" is a statement of ________ law.

A) Charles's
B) Boyle's
C) Dalton's
D) Avogadro's
E) Gay-Lussac's

Question 11

A sample of a gas has an initial pressure of 0.987 atm and a volume of 12.8 L. What is the final pressure if the volume is increased to 25.6 L?

A) 2.03 atm
B) 1.97 atm
C) 0.494 atm
D) 0.003 atm
E) 323.4 atm

Question 12

The air pressure in a volleyball is 75 psi. What is this pressure in torr? (1 atm = 14.7 psi = 101,325 Pa = 760 torr)?

A) 520 torr
B) 562 torr
C) 3900 torr
D) 7600 torr
E) 75,000 torr

Question 13

Choose all answers that apply. Which of the following is/are characteristic(s) of gases?

A) High compressibility
B) Has a static volume regardless of temperature and pressure
C) Formation of homogeneous mixtures regardless of the nature of gases
D) Relatively large distances between molecules
E) Always has a density of 1.00 gram per liter

Question 14

Which represents the definition of pressure?

A) volume/density
B) temperature × area
C) moles/volume
D) force/area
E) volume × force

Question 15

A flask containing neon gas is connected to an open-ended mercury manometer. The open end is exposed to the atmosphere, where the prevailing pressure is 745 torr. The mercury level in the open arm is 5.0 cm below that in the arm connected to the flask of neon. What is the neon pressure, in torr?

A) -50. torr
B) 50. torr
C) 695 torr
D) 745 torr
E) 795 torr

Question 16

A pressure that will support a column of Hg to a height of 256 mm would support a column of water to what height? The density of mercury is 13.6 g/cm³; the density of water is 1.00 g/cm³.

A) 348 cm
B) 1.00 × 10² ft
C) 18.8 mm
D) 33.8 ft
E) 76.0 cm

Question 17

A sample of nitrogen gas at 298 K and 745 torr has a volume of 37.42 L. What volume will it occupy if the pressure is increased to 894 torr at constant temperature?

A) 22.3 L
B) 31.2 L
C) 44.9 L
D) 112 L
E) 380 L

Question 18

A sample of hydrogen gas exerts a pressure of 466 torr in a container. What is this pressure in atmospheres? (1 atm = 1.01325 ×10⁵ Pa = 760 torr)

A) 0.217 atm
B) 0.466 atm
C) 0.613 atm
D) 1.63 atm
E) 4.60 atm

Question 19

What is the formula which describes the relationship between the pressure and volume at constant temperature and constant number of moles?

A) PV = k₁
B) V/P = k₁
C) P/V = k₁
D) k₁P = V
E) P = -k₁V

Question 20

If the atmospheric pressure in Denver is 0.8800 atm, what is this pressure expressed in mmHg? (1 atm = 101,325 Pa = 760 torr, 1 torr = 1 mmHg)?

A) 151.5 mmHg
B) 1.16 × 10^-3 mmHg
C) 863.6 mmHg
D) 8.92 × 10⁴ mmHg
E) 668.8 mmHg

Question 21

A sample of gas occupies 24.5 L at a pressure of 1.57 atm. What is the pressure if the volume is increased to 48.3 L at constant temperature?

A) 0.796 atm
B) 1.26 atm
C) 3.10 atm
D) 5.38 × 10^-4 atm
E) 1.86 × 10³ atm

Question 22

A fixed quantity of gas has a pressure of 1.35 atm, a volume of 23.8 L, and a temperature of 205.1 K. If the pressure increases to 2.84 atm and the temperature rises to 233.4 K, what is the new volume of the gas?

A) 0.183 L
B) 7.06 L
C) 9.94 L
D) 12.9 L
E) 57.0 L

Question 23

What is the formula which describes the relationship between the pressure, volume, temperature, and moles?

A)
B)
C)
D)
E)

Question 24

What is the formula which describes the relationship between the volume and temperature at constant pressure and constant number of moles?

A) VT = k₂
B) V²/T = k₂
C) V = k₂T
D) k₂VT = 0
E) V = -k₂T

Question 25

What is the volume of NH₃ produced in the following reaction when 3.0 L of N₂ reacts with 4.0 L of H₂ ? N₂(g) + 3H₂(g) → 2NH₃(g)

A) 1.5 L
B) 2.7 L
C) 6.0 L
D) 7.5 L
E) 12 L

Question 26

What is the formula which describes the relationship between the volume and number of moles in the sample at constant pressure and constant temperature?

A) Vn = k₃
B) V² /n = k₃
C) n/V² = k₃
D) V/n = k₃
E) V = -k₃n

Question 27

What is the temperature in Celsius at 77 K, which is the normal boiling point of liquid nitrogen?

A) -350°C
B) -196°C
C) 350°C
D) 196°C
E) 3.55°C

Question 28

A sample of nitrogen gas has the temperature drop from 250.°C to 150.°C at constant pressure. What is the final volume if the initial volume is 310. mL?

A) 0.186 L
B) 0.251 L
C) 0.383 L
D) 0.410 L
E) 0.517 L

Question 29

What is the Kelvin temperature at 24°C?

A) 249 K
B) 11.4 K
C) -297 K
D) -249 K
E) 297 K

Question 30

What is the temperature in Celsius at 4 K, which is the normal boiling point of liquid helium?

A) -269°C
B) 269°C
C) 277°C
D) 68.3°C
E) -277°C

Question 31

A sample of a gas occupies 1.40 L at 25°C and 760 mmHg. What volume will it occupy at the same temperature and 380 mmHg?

A) 2.8 L
B) 2.10 L
C) 1.40 L
D) 1.05 L
E) 0.700 L

Question 32

What are the conditions of STP?

A) 0 K and 1 atm
B) 273.15 K and 760 torr
C) 0°C and 760 atm
D) 273.15°C and 760 torr
E) 0°C and 1 torr

Question 33

A gas sample occupies 8.76 L at a temperature of 37°C. What is the volume if the temperature is lowered to 0°C at constant pressure?

A) 9.95 L
B) 0 L
C) 4.22 L
D) 74.1 L
E) 7.71 L

Question 34

A sample of carbon dioxide gas at 125°C and 248 torr occupies a volume of 275 L. What will the gas pressure be if the volume is increased to 321 L at 125°C?

A) 212 torr
B) 289 torr
C) 356 torr
D) 441 torr
E) 359 torr

Question 35

What is the final temperature of a gas that expands from a volume of 22.4 L at 278 K to a volume of 38.3 L at constant pressure?

A) 163 K
B) 294 K
C) 3.09 K
D) 217 K
E) 475 K

Question 36

If 2.38 mol of a gas has a volume of 120.0 mL, what is the volume of 1.97 mol of the gas at the same temperature and pressure?

A) 25.6 mL
B) 99.3 mL
C) 119 mL
D) 145 mL
E) 563 mL

Question 37

A sample of N₂ gas occupies 2.40 L at 20°C. At what temperature will the N₂ gas occupy a volume of 4.80 L at constant pressure?

A) 10°C
B) 40°C
C) 146°C
D) 313°C
E) 586°C

Question 38

A sample of nitrogen gas has a volume of 32.4 L at 20°C. The gas is heated to 220ºC at constant pressure. What is the final volume of the nitrogen gas?

A) 2.94 L
B) 19.3 L
C) 32.4 L
D) 54.5 L
E) 356 L

Question 39

If 2.3 mol of a gas occupies 50.5 mL, how many moles of the gas will occupy 85.5 mL at the same temperature and pressure?

A) 1.4 mol
B) 0.59 mol
C) 3.9 mol
D) 0.26 mol
E) 2.3 mol

Question 40

If 25.5 L of oxygen are cooled from 150^oC to 50^oC at constant pressure, what is the new volume of oxygen?

A) 0.0514 L
B) 19.5 L
C) 33.4 L
D) 0.03 L
E) 8.5 L

Question 41

What is the molar mass of an unknown gas if a sample weighing 0.389 g is collected in a flask with a volume of 102 cm³ at 97°C and at a pressure of 728 mmHg? (R = 0.08206 L • atm/K • mol, 1 atm = 760 mmHg).

A) 187 g/mol
B) 121 g/mol
C) 112 g/mol
D) 31.6 g/mol
E) 8.28 × 10^-3 g/mol

Question 42

A gas evolved during the fermentation of sugar was collected at 22.5°C and 702 mmHg. After purification its volume was found to be 25.0 L. How many moles of gas were collected? (R = 0.08206 L • atm/K • mol, 1 atm = 760 mmHg)

A) 0.952 mol
B) 1.05 mol
C) 12.5 mol
D) 22.4 mol
E) 724 mol

Question 43

A 0.271-g sample of an unknown vapor occupies 294 mL at 140°C and 847 mmHg. The empirical formula of the compound is CH₂. What is the molecular formula of the compound? (R = 0.08206 L • atm/K • mol)

A) CH₂
B) C₂H₄
C) C₃H₆
D) C₄H₈
E) C₆H₁₂

Question 44

What is the volume occupied by 35.2 g of methane gas (CH₄) at 25°C and 1.0 atm? (R = 0.08206 L • atm/K • mol)

A) 0.0186 L
B) 4.5 L
C) 11.2 L
D) 49.2 L
E) 53.7 L

Question 45

Determine the molar mass of Freon-11 gas if a sample weighing 0.597 g occupies 100 cm³ at 95°C and 1000 mmHg (R = 0.08206 L • atm/K • mol, 1 atm = 760 mmHg).

A) 0.19 g/mol
B) 35.3 g/mol
C) 70.9 g/mol
D) 137 g/mol
E) 384 g/mol

Question 46

What is the volume occupied by 25.2 g of CO₂ at 0.840 atm and 25°C? (R = 0.08206 L • atm/K • mol)

A) 0.060 L
B) 1.34 L
C) 16.7 L
D) 24.2 L
E) 734 L

Question 47

Gases are sold in large cylinders for laboratory use. What pressure is exerted by 2.500 kg of oxygen gas (O₂) stored at 22°C in a 40.0-L cylinder? (R = 0.08206 L • atm/K • mol)

A) 3.55 atm
B) 1.51 ×10³ atm
C) 47.3 atm
D) 7.56 × 10⁴ atm
E) 10.2 atm

Question 48

A sample of propane, a component of LP gas, has a volume of 35.3 L at 315 K and 922 torr. What is its volume at STP? (R = 0.08206 L • atm/K • mol, 1 atm = 760 torr)

A) 25.2 L
B) 30.6 L
C) 33.6 L
D) 37.1 L
E) 49.2 L

Question 49

A sample of nitrogen gas is confined to a 14.0-L container at 375 torr and 37.0°C. How many moles of nitrogen are in the container? (R = 0.08206 L • atm/K • mol, 1 atm = 760 torr)

A) 0.272 mol
B) 2.27 mol
C) 3.69 mol
D) 206 mol
E) 227 mol

Question 50

How many molecules of N₂ gas are present in a 2.5-L flask at 50°C and 650 mmHg? (R = 0.08206 L • atm/K • mol, 1 atm = 760 mmHg, 1 mole = 6.022 × 10²³ molecules)

A) 2.1 × 10^-23 molecules
B) 4.9 × 10²² molecules
C) 3.1 × 10²³ molecules
D) 3.6 × 10²⁵ molecules
E) 0.081 molecules

Question 51

What is the density of Ar(g) at -11°C and 675 mmHg? (R = 0.08206 L • atm/K • mol, 1 atm = 760 mmHg)

A) 1.52 g/L
B) 1.65 g/L
C) -39.3 g/L
D) 40.0 g/L
E) 1.25 kg/L

Question 52

A gas cylinder containing 1.50 mol compressed methane has a volume of 3.30 L. What pressure does the methane exert on the walls of the cylinder if its temperature is 25°C? (R = 0.08206 L • atm/K • mol)

A) 9.00 × 10^-2 atm
B) 0.933 atm
C) 1.11 atm
D) 1.70 atm
E) 11.1 atm

Question 53

What is the mass, in grams, of 2.74 L of CO gas measured at 33°C and 945 mmHg? (R = 0.08206 L • atm/mol • K, 1 atm = 760 mmHg)

A) 0.263 g
B) 2.46 g
C) 3.80 g
D) 35.2 g
E) 206 g

Question 54

What is the density of carbon dioxide gas at -25.2°C and 98.0 kPa? (R = 0.08206 L • atm/K • mol, 1 atm = 101,325 Pa)

A) 0.232 g/L
B) 0.279 g/L
C) 0.994 g/L
D) 1.74 g/L
E) 2.09 g/L

Question 55

What is the initial pressure of a gas having an initial temperature of 905 K, an initial volume of 14.3 L, a final pressure of 0.83 atm, a final temperature of 154 K and a final volume of 2.7 L?

A) 26 atm
B) 0.27 atm
C) 0.75 atm
D) 1.3 atm
E) 0. 92 atm

Question 56

A flask with a volume of 3.16 L contains 9.33 g of an unknown gas at 32.0°C and 1.00 atm. What is the molar mass of the gas? (R = 0.08206 L • atm/K • mol)

A) 7.76 g/mol
B) 66.1 g/mol
C) 73.9 g/mol
D) 81.4 g/mol
E) 144 g/mol

Question 57

What is the density of CO₂(g) at 100.°C and 10.0 atm pressure? (R = 0.08206 L • atm/K • mol)

A) 1.44 g/L
B) 134 g/L
C) 44.0 g/L
D) 53.6 g/L
E) 14.4 g/L

Question 58

If a fixed amount of a gas is at a pressure of 2.71 atm and has a volume of 85.3 L at a temperature of 173.4 K, what is the final temperature of the gas if the pressure changes to 1.04 atm in a 105.3 L container?

A) 49.8 K
B) 75.9 K
C) 366.0 K
D) 82.1 K
E) 557.8 K

Question 59

Assuming ideal behavior, what is the density of argon gas at STP? (R = 0.08206 L • atm/K • mol)

A) 0.0176 g/L
B) 0.0250 g/L
C) 0.0561 g/L
D) 1.78 g/L
E) 181 g/L

Question 60

What is the density of SF₆(g) at 27°C and 0.500 atm pressure? (R = 0.08206 L • atm/K • mol)

A) 3.38 × 10^-3 g/L
B) 2.97 g/L
C) 22.4 g/L
D) 32.9 g/L
E) 3.38 kg/L

Question 61

When active metals such as magnesium are immersed in acid solution, hydrogen gas is evolved. Calculate the volume of H₂(g) at 30.1°C and 0.85 atm that can be formed when 275 mL of 0.725 M HCl solution reacts with excess Mg to give hydrogen gas and aqueous magnesium chloride. Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)
(R = 0.08206 L • atm/K • mol)

A) 3.4 × 10^-3 L
B) 2.2 L
C) 2.9 L
D) 5.8 L
E) 11.7 L

Question 62

A spacecraft is filled with 0.500 atm of N₂ and 0.500 atm of O₂. Suppose an object strikes this spacecraft and puts a very small hole in its side. Under these circumstances,

A) O₂ is lost from the craft 6.9% faster than N₂ is lost.
B) O₂ is lost from the craft 14% faster than N₂ is lost.
C) N₂ is lost from the craft 6.9% faster than O₂ is lost.
D) N₂ is lost from the craft 14% faster than O₂ is lost.
E) N₂ and O₂ are lost from the craft at the same rate.

Question 63

What mass of KClO₃ must be decomposed to produce 126 L of oxygen gas at 133°C and 0.880 atm? (The other reaction product is solid KCl.) (R = 0.08206 L • atm/K • mol)

A) 24.6 g
B) 70.8 g
C) 272 g
D) 408 g
E) 612 g

Question 64

At what temperature is the root mean square speed of helium gas equal to that of oxygen gas at 300. K?

A) 37.5 K
B) 75 K
C) 106 K
D) 292 K
E) 2400. K

Question 65

1.000 atm of oxygen gas, placed in a container having a pinhole opening in its side, leaks from the container 2.14 times faster than does 1.000 atm of an unknown gas placed in this same apparatus. Which of the following species could be the unknown gas?

A) Cl₂
B) SF₆
C) Kr
D) UF₆
E) Xe

Question 66

A block of dry ice (solid CO₂, density = 1.56 g/mL) of dimensions 25.0 cm × 25.0 cm × 25.0 cm is left to sublime (i.e., to pass from the solid phase to the gas phase) in a closed chamber of dimensions 4.00 m × 5.00 m × 3.00 m. Once the sublimation is complete, what is the partial pressure of carbon dioxide in the chamber at 25°C? (R = 0.08206 L • atm/K • mol, 1 atm = 760 mmHg)

A) 172 mmHg
B) 107 mmHg
C) 0.225 mmHg
D) 0.172 mmHg
E) 14.4 mmHg

Question 67

A gaseous compound is 30.4% nitrogen and 69.6% oxygen by mass. A 5.25-g sample of the gas occupies a volume of 1.00 L and exerts a pressure of 1.26 atm at -4.0°C. What is its molecular formula? (R = 0.08206 L • atm/K • mol)

A) NO
B) NO₂
C) N₃O₆
D) N₂O₄
E) N₂O₅

Question 68

Arrange the following gases in order of increasing rate of effusion: C₂H₆, Ar, HCl, and PH₃.

A) Ar < HCl3 < C₂H₆
B) C₂H₆ < PH₃ < HCl < Ar
C) Ar < PH₃ < C₂H₆ < HCl
D) C₂H₆ < HCl < PH₃ < Ar
E) Ar < PH₃ < HCl < C₂H₆

Question 69

A 250.0-mL sample of ammonia, NH₃(g), exerts a pressure of 833 torr at 42.4°C. What mass of ammonia is in the container? (R = 0.08206 L • atm/K • mol, 1 atm = 760 torr)

A) 0.0787 g
B) 0.180 g
C) 8.04 g
D) 17.0 g
E) 59.8 g

Question 70

What volume of chlorine gas at 25°C and 0.950 atm can be produced by the reaction of 12.0 g of MnO₂ in excess HCl(aq)? MnO₂(s) + 4HCl(aq) → MnCl₂(aq) + 2H₂O(l) + Cl₂(g)
(R = 0.08206 L • atm/K • mol)

A) 5.36 × 10^-3 L
B) 0.138 L
C) 0.282 L
D) 3.09 L
E) 3.55 L

Question 71

The mole fraction of oxygen molecules in dry air is 0.2095. What volume of dry air at 1.00 atm and 25°C is required for burning completely 1.00 L of octane (C₈H₁₈, density = 0.7025 g/mL), yielding carbon dioxide and water? (R = 0.08206 L • atm/K • mol)

A) 394 L
B) 1880 L
C) 8220 L
D) 8970 L
E) 17,900 L

Question 72

A 2.50-L flask contains a mixture of methane (CH₄) and propane (C₃H₈) at a pressure of 1.45 atm and 20°C. When this gas mixture is then burned in excess oxygen, 8.60 g of carbon dioxide is formed. (The other product is water.) What is the mole fraction of methane in the original gas mixture?

A) 0.34
B) 1.00
C) 0.66
D) 0.85
E) 0.15

Question 73

A 7.75-L flask contains 0.482 g of hydrogen gas and 4.98 g of oxygen gas at 65°C. What is the partial pressure of oxygen in the flask?

A) 0.557 atm
B) 0.043 atm
C) 1.11 atm
D) 33.5 atm
E) 67 atm

Question 74

Which of the following gases effuses most rapidly?

A) nitrogen
B) oxygen
C) hydrogen chloride
D) ammonia
E) carbon monoxide

Question 75

What volume of CO₂ gas at 645 torr and 800. K could be produced by the decomposition of 45.0 g of CaCO₃? CaCO₃(s) → CaO(s) + CO₂(g)
(R = 0.08206 L • atm/K • mol)

A) 0.449 L
B) 22.4 L
C) 25.0 L
D) 34.8 L
E) 45.7 mL

Question 76

Calculate the volume of H₂(g) at 273 K and 2.00 atm that will be formed when 275 mL of 0.725 M HCl solution reacts with 50.0 g Zn(s) to give hydrogen gas and aqueous zinc chloride. (R = 0.08206 L • atm/K • mol)

A) 0.56 L
B) 1.12 L
C) 2.23 L
D) 4.47 L
E) 3.54 L

Question 77

A 3.0-L sample of helium was placed in container fitted with a porous membrane. Half of the helium effused through the membrane in 24 hours. A 3.0-L sample of oxygen was placed in an identical container. How many hours will it take for half of the oxygen to effuse through the membrane?

A) 8.5 h
B) 12 h
C) 48 h
D) 60. h
E) 68 h

Question 78

A compound composed of carbon, hydrogen, and chlorine effuses through a pinhole 0.411 times as fast as neon. What is the molecular formula of the compound?

A) CHCl₃
B) CH₂Cl₂
C) C₂H₂Cl₂
D) C₂H₃Cl
E) CCl₄

Question 79

The catalytic decomposition of hydrogen peroxide yields oxygen gas and water. In an experiment, decomposition of hydrogen peroxide yielded 75.3 mL of gas collected over water at 25°C and 742 torr. What mass of oxygen gas was collected? (P_water = 24 torr at 25°C, R = 0.08206 L • atm/K • mol)

A) 0.00291 g
B) 0.0931 g
C) 0.0962 g
D) 0.0993 g
E) 0.962 g

Question 80

Magnesium metal (0.100 mol) and hydrochloric acid (0.500 mol HCl) are combined and react to completion. What volume of hydrogen gas, measured at STP, is produced? Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)
(R = 0.08206 L • atm/K • mol)

A) 2.24 L of H₂
B) 4.48 L of H₂
C) 5.60 L of H₂
D) 11.2 L of H₂
E) 22.4 L of H₂