Deck 5: Gases

Question 1

At what temperature will a fixed amount of gas with a volume of 175 L at 15°C and 760 mmHg occupy a volume of 198 L at a pressure of 640 mm Hg?

A)274°C
B)214°C
C)114°C
D)1°C
E)-59°C

Answer 1

1°C

Question 2

The pressure of a gas sample was measured to be 489 mmHg.Which of the following is not an equivalent statement of that pressure? (1 atm = 1.01325 * 10⁵ Pa)

A)65.2 kPa
B)6.52 * 10⁴ Pa
C)489 torr
D)0.811 atm

Answer 2

0.811 atm

Question 3

What will happen to the height (h)of the mercury column in the manometer shown below if the stopcock is opened, given that the atmospheric pressure is 755 mmHg?

A)h will decrease
B)h will not change
C)h will increase
D)not enough information given to answer the question

Answer 3

h will decrease

Question 4

The gas pressure in an aerosol can is 1.8 atm at 25°C. If the gas is an ideal gas, what pressure would develop in the can if it were heated to 475°C?

A)0.095 atm
B)0.717 atm
C)3.26 atm
D)4.52 atm
E)34.2 atm

Question 5

The pressure of a gas sample was measured to be 654 mmHg.What is the pressure in kPa? (1 atm = 1.01325 * 10⁵ Pa)

A)87.2 kPa
B)118 kPa
C)6.63 * 10⁴ kPa
D)8.72 * 10⁴ kPa
E)8.72 * 10⁷ kPa

Question 6

The temperature of an ideal gas in a 5.00 L container originally at 1 atm pressure and 25°C is lowered to 220 K. Calculate the new pressure of the gas.

A)1.0 atm
B)1.35 atm
C)8.8 atm
D)0.738 atm
E)0.114 atm

Question 7

Which of these properties is/are characteristic(s)of gases?

A)High compressibility
B)Relatively large distances between molecules
C)Formation of homogeneous mixtures regardless of the nature of gases
D)A and B.
E)A, B, and C.

Question 8

If 30.0 L of oxygen are cooled from 200ºC to 1°C at constant pressure, what is the new volume of oxygen?

A)0.150 L
B)17.4 L
C)23.0 L
D)51.8 L
E)6.00 * 10³ L

Question 9

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 nitrogen?

A)2.94 L
B)19.3 L
C)31.4 L
D)54.5 L
E)356 L

Question 10

A sample of N₂ gas occupies 2.40 L at 20°C. If the gas is in a container that can contract or expand at constant pressure, at what temperature will the N₂ occupy 4.80 L?

A)10°C
B)40°C
C)146°C
D)313°C
E)685°C

Question 11

At what temperature will a fixed mass of gas with a volume of 125 L at 15°C and 750 mmHg occupy a volume of 101 L at a pressure of 645 mm Hg?

A)-73°C
B)10.4°C
C)2°C
D)34°C
E)200°C

Question 12

If the pressure of a gas sample is quadrupled and the absolute temperature is doubled, by what factor does the volume of the sample change?

A)8
B)2
C)1/2
D)1/4
E)1/8

Question 13

If the pressure on a gas sample is tripled and the absolute temperature is quadrupled, by what factor will the volume of the sample change?

A)12
B)4/3
C)3/4
D)1/3
E)4

Question 14

A small bubble rises from the bottom of a lake, where the temperature and pressure are 4°C and 3.0 atm, to the water's surface, where the temperature is 25°C and the pressure is 0.95 atm.Calculate the final volume of the bubble if its initial volume was 2.1 mL.

A)0.72 mL
B)6.2 mL
C)41.4 mL
D)22.4 mL
E)7.1 mL

Question 15

A sample of a gas occupies 1.40 *10³ mL at 25°C and 760 mmHg. What volume will it occupy at the same temperature and 380 mmHg?

A)2,800 mL
B)2,100 mL
C)1,400 mL
D)1,050 mL
E)700 mL

Question 16

What will happen to the height (h)of the column of mercury in the manometer shown below if the stopcock is opened?

A)h will decrease
B)h will not change
C)h will increase
D)not enough information given to answer the question

Question 17

Calculate 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 18

Calculate the number of moles of gas contained in a 10.0 L tank at 22°C and 105 atm.(R = 0.08206 L.atm/K.mol)

A)1.71 * 10^-3 mol
B)0.0231 mol
C)1.03 mol
D)43.4 mol
E)582 mol

Question 19

What is the pressure of the sample of gas trapped in the open-tube mercury manometer shown below if atmospheric pressure is 736 mmHg and h = 9.2 cm?

A)92 mmHg
B)644 mmHg
C)736 mmHg
D)828 mmHg

Question 20

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

Question 21

Determine the molar mass of chloroform gas if a sample weighing 0.389 g is collected in a flask with a volume of 102 cm³ at 97°C. The pressure of the chloroform is 728 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 22

Calculate the mass, in grams, of 2.74 L of CO gas measured at 33°C and 945 mmHg.

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

Question 23

Calculate the density of Br₂(g)at 59.0°C and 1.00 atm pressure.

A)27.2 g/L
B)5.83 g/L
C)769 g/L
D)22.4 g/L
E)3.45 g/L

Question 24

Two moles of chlorine gas at 20.0°C are heated to 350°C while the volume is kept constant.The density of the gas

A)increases.
B)decreases.
C)remains the same.
D)Not enough information is given to correctly answer the question.

Question 25

What is the molar mass of Freon-11 gas if its density is 6.13 g/L at STP?

A)0.274 g/mol
B)3.64 g/mol
C)78.2 g/mol
D)137 g/mol
E)365 g/mol

Question 26

Calculate the density of CO₂(g)at 100°C and 10.0 atm pressure.

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 27

A 1.2 L flask contains 0.500 mole of ammonia (NH₃)at 150°C. Calculate the pressure of the ammonia inside the flask.

A)6.91 * 10^-2 atm
B)5.13 atm
C)12.2 atm
D)14.5 atm
E)22.4 atm

Question 28

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?

A)CH₂
B)C₂H₄
C)C₃H₆
D)C₄H₈
E)C₆H₁₂

Question 29

Calculate the volume occupied by 25.2 g of CO₂ at 0.84 atm and 25°C.R = 0.08206 L.atm/K.mol.

A)0.060 L
B)1.34 L
C)16.9 L
D)24.2 L
E)734 L

Question 30

Gases are sold in large cylinders for laboratory use. What pressure, in atmospheres, will be exerted by 2,500 g of oxygen gas (O₂)when stored at 22°C in a 40.0 L cylinder?

A)3.55 atm
B)1,510 atm
C)47.3 atm
D)7.56 * 10⁴ atm
E)10.2 atm

Question 31

A 1.17 g sample of an alkane hydrocarbon gas occupies a volume of 674 mL at 28°C and 741 mmHg.Alkanes are known to have the general formula CnH2n+2.What is the molecular formula of the gas in this sample? (R = 0.08206 L.atm/K.mol)

A)CH₄
B)C₂H₆
C)C₃H₈
D)C₄H₁₀
E)C₅H₁₂

Question 32

Calculate the density, in g/L, of CO₂ gas at 27°C and 0.50 atm pressure.

A)0.89 g/L
B)1.12 g/L
C)9.93 g/L
D)46.0 g/L
E)2.17 kg/L

Question 33

Determine the molar mass of Freon-11 gas if a sample weighing 0.597 g occupies 100.cm³ at 95°C, and 1,000.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 34

Calculate the density of Ar(g)at -11°C and 675 mmHg.

A)1.52 g/L
B)1.65 g/L
C)-39.3 g/L
D)39.95 g/L
E)1254 g/L

Question 35

Which of these gases will have the greatest density at the same specified temperature and pressure?

A)H₂
B)CClF₃
C)CO₂
D)C₂H₆
E)CF₄

Question 36

How many molecules of N₂ gas can be present in a 2.5 L flask at 50°C and 650 mmHg?

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 37

Calculate the density, in g/L, of SF₆ gas at 27°C and 0.500 atm pressure.

A)3.38 * 10^-3 g/L
B)2.96 g/L
C)22.4 g/L
D)32.9 g/L
E)3.38 kg/L

Question 38

Calculate the density, in g/L, of chlorine (Cl₂)gas at STP.

A)2.13 * 10^-2 g/L
B)46.9 g/L
C)1.58 g/L
D)3.16 g/L
E)0.316 kg/L

Question 39

Which one of these gases is "lighter-than-air"?

A)Cl₂
B)SO₂
C)PH₃
D)NO₂
E)Ne

Question 40

A gas evolved during the fermentation of sugar was collected.After purification its volume was found to be 25.0 L at 22.5°C and 702 mmHg.How many moles of gas were collected?

A)0.95 mol
B)1.05 mol
C)12.5 mol
D)22.4 mol
E)724 mol

Question 41

How many liters of oxygen gas at 153°C and 0.820 atm can be produced by the decomposition of 22.4 g of solid KClO₃? (The other decomposition product is solid potassium chloride.)

A)3.0 L
B)0.085 L
C)4.20 L
D)7.79 L
E)11.7 L

Question 42

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. Which of these choices is its molecular formula?

A)NO
B)NO₂
C)N₃O₆
D)N₂O₄
E)N₂O₅

Question 43

How many liters of chlorine gas at 25°C and 0.950 atm can be produced by the reaction of 12.0 g of MnO₂ with excess HCl(aq)according to the following chemical equation? MnO₂(s)+ 4HCl(aq) $\rarr$ MnCl₂(aq)+ 2H₂O(l)+ Cl₂(g)

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

Question 44

Which statement is false?

A)The average kinetic energies of molecules from samples of different "ideal" gases is the same at the same temperature.
B)The molecules of an ideal gas are relatively far apart.
C)All molecules of an ideal gas have the same kinetic energy at constant temperature.
D)Molecules of a gas undergo many collisions with each other and the container walls.
E)Molecules of greater mass have a lower average speed than those of less mass at the same temperature.

Question 45

What volume of CO₂ gas at 645 torr and 800 K could be produced by the reaction of 45 g of CaCO₃ according to the equation? CaCO₃(s) $\rarr$ CaO(s)+ CO₂(g)

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

Question 46

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.)

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

Question 47

A sample of hydrogen gas was collected over water at 21°C and 685 mmHg. The volume of the container was 7.80 L. Calculate the mass of H₂(g)collected. (Vapor pressure of water = 18.6 mmHg at 21°C.)

A)0.283 g
B)0.572 g
C)0.589 g
D)7.14 g
E)435 g

Question 48

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 excess Mg to give hydrogen gas and aqueous magnesium chloride.

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

Question 49

What volume of oxygen gas at 320 K and 680 torr will react completely with 2.50 L of NO gas at the same temperature and pressure? 2NO(g)+ O₂(g) $\rarr$ 2NO₂(g)

A)1.25 L
B)2.50 L
C)3.00 L
D)1.00 L
E)5.00 L

Question 50

A sample of carbon monoxide gas was collected in a 2.0 L flask by displacing water at 28°C and 810 mmHg. Calculate the number of CO molecules in the flask. The vapor pressure of water at 28°C is 28.3 mmHg.

A)5.0 * 10²²
B)5.2 * 10²²
C)3.8 * 10²³
D)5.4 * 10²³
E)3.8 * 10²⁵

Question 51

Which gas has molecules with the greatest average molecular speed at 25°C?

A)CH₄
B)Kr
C)N₂
D)CO₂
E)Ar

Question 52

Which of these gas molecules have the highest average kinetic energy at 25°C?

A)H₂
B)O₂
C)N₂
D)Cl₂
E)All the gases have the same average kinetic energy.

Question 53

The molecules of different samples of an ideal gas have the same average kinetic energies, at the same

A)pressure.
B)temperature.
C)volume.
D)density.

Question 54

Gas A and gas B are combined in a flask at initial pressures of 1.0 atm each.The flask is sealed and over time they react to completion to give gas C according to the following chemical equation: 2A(g)+ B(g) $\rarr$ C(g)
Assuming the temperature stays constant, what will be the total pressure in the flask after the reaction goes to completion?

A)0.33 atm
B)0.50 atm
C)0.67 atm
D)0.75 atm
E)1.0 atm

Question 55

If equal masses of O₂(g)and HBr(g)are in separate containers of equal volume and temperature, which one of these statements is true?

A)The pressure in the O₂ container is greater than that in the HBr container.
B)There are more HBr molecules than O₂ molecules.
C)The average velocity of the O₂ molecules is less than that of the HBr molecules.
D)The average kinetic energy of HBr molecules is greater than that of O₂ molecules.
E)The pressures of both gases are the same.

Question 56

A mixture of three gases has a total pressure of 1,380 mmHg at 298 K. The mixture is analyzed and is found to contain 1.27 mol CO₂, 3.04 mol CO, and 1.50 mol Ar. What is the partial pressure of Ar?

A)0.258 atm
B)301 mmHg
C)356 mmHg
D)5,345 mmHg
E)8,020 mmHg

Question 57

Liquid nitrogen has a density of 0.807 g/mL at -195.8 °C.If 1.00 L of N₂(l)is allowed to warm to 25°C at a pressure of 1.0 atm, what volume will the gas occupy? (R = 0.08206 L.atm/K.mol)

A)59.1 L
B)182 L
C)705 L
D)1.41 * 10³ L
E)1.97 * 10⁴ L

Question 58

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.

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

Question 59

A 1.07 g sample of a Noble gas occupies a volume of 363 mL at 35°C and 678 mmHg.Identify the Noble gas in this sample? (R = 0.08206 L.atm/K.mol)

A)He
B)Ne
C)Ar
D)Kr
E)Xe

Question 60

Air contains 78% N₂, 21% O₂, and 1% Ar, by volume. What is the density of air at 1,000.torr and -10°C?

A)1.0 g/L
B)6.1 g/L
C)1.3 g/L
D)1.8 g/L
E)0.56 g/L

Question 61

A method of removing CO₂ from a spacecraft is to allow the CO₂ to react with sodium hydroxide. (The products of the reaction are sodium carbonate and water.)What volume of carbon dioxide at 25°C and 749 mmHg can be removed per kilogram of sodium hydroxide that reacts?

A)301 L
B)284 L
C)276 L
D)310 L
E)620 L

Question 62

What is standard temperature and standard pressure?

Question 63

What is the pressure (in atmospheres)of the sample of gas trapped in the open-tube mercury manometer shown below if atmospheric pressure is 735 mmHg and h = 8.3 cm?

Question 64

What is the pressure of the gas trapped in the apparatus shown below when the atmospheric pressure is 720 mmHg?

A)12 mmHg
B)708 mmHg
C)720 mmHg
D)732 mmHg
E)760 mmHg

Question 65

A spacecraft is filled with 0.500 atm of N₂ and 0.500 atm of O₂. Suppose a micrometeor strikes this spacecraft and puts a very small hole in it's 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 66

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)0.341
B)1.00
C)0.659
D)0.855
E)0.145

Question 67

Samples of the following volatile liquids are opened simultaneously at one end of a room. If you are standing at the opposite end of this room, which species would you smell first? (Assume that your nose is equally sensitive to all these species.)

A)ethyl acetate (CH₃COOC₂H₅)
B)camphor (C₁₀H₁₆O)
C)diethyl ether (C₂H₅OC₂H₅)
D)naphthalene (C₁₀H₈)
E)pentanethiol (C₅H₁₁SH)

Question 68

A spacecraft is filled with 0.500 atm of O₂ and 0.500 atm of He. If there is a very small hole in the side of this craft such that gas is lost slowly into outer space,

A)He is lost 2.8 times faster than O₂ is lost.
B)He is lost 8 times faster than O₂ is lost.
C)He is lost twice as fast as O₂ is lost.
D)O₂ is lost 2.8 times faster than He is lost.
E)O₂ is lost 8 times faster than He is lost.

Question 69

What is the pressure of the sample of gas trapped in the closed-tube mercury manometer shown below if atmospheric pressure is 751 mmHg and h = 17.3 cm?

Question 70

A sample of mercury(II)oxide is placed in a 5.00 L evacuated container and heated until it decomposes entirely to mercury metal and oxygen gas. The container is then cooled to 25°C. One now finds that the gas pressure inside the container is 1.73 atm. What mass of mercury(II)oxide was originally placed into the container?

A)913 g
B)76.6 g
C)1.51 g
D)45.6 g
E)153 g

Question 71

What is the significance of the magnitude of the van der Waals "a" constant?

Question 72

For a substance that remains a gas under the conditions listed, deviation from the ideal gas law would be most pronounced at

A)100°C and 2.0 atm.
B)0°C and 2.0 atm.
C)-100°C and 2.0 atm.
D)-100°C and 4.0 atm.
E)100°C and 4.0 atm.

Question 73

Deviations from the ideal gas law are greater at

A)low temperatures and low pressures.
B)low temperatures and high pressures.
C)high temperatures and high pressures.
D)high temperatures and low pressures.

Question 74

What is the definition of a "gas"?

Question 75

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. The partial pressure of carbon dioxide in this chamber at 25°C will be

A)171 mmHg
B)107 mmHg
C)0.225 mmHg
D)0.171 mmHg
E)14.4 mmHg

Question 76

What is the pressure of the sample of gas trapped in the open-tube mercury manometer shown below if atmospheric pressure is 742 mmHg and h = 16.7 cm?

Question 77

Determine the pressure of the gas trapped in the apparatus shown below when the atmospheric pressure is 695 mmHg.

A)45 mmHg
B)650 mmHg
C)695 mmHg
D)740 mmHg
E)760 mmHg

Question 78

What is the pressure (in atmospheres)of the sample of gas trapped in the closed-tube mercury manometer shown below if h = 23.6 cm?

Question 79

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 1.00 L of hexane (C₆H₁₄, density = 0.660 g/mL)completely, yielding carbon dioxide and water?

A)187 L
B)712 L
C)1780 L
D)894 L
E)8490

Question 80

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 1.00 L of octane (C₈H₁₈, density = 0.7025 g/mL)completely, yielding carbon dioxide and water?

A)718 L
B)367 L
C)8980 L
D)1880 L
E)150 L