Deck 11: Gases and Their Properties

Question 1

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.

Answer 1

The volume of a gas sample varies directly with the absolute temperature.

Question 2

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
B) 19.0 L
C) 0.0132 L
D) 38 L
E) 3.80 L

Answer 2

76.0 L

Question 3

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) The pressure decreases by a factor of three.
B) The pressure decreases by a factor of four.
C) The pressure increases by a factor of two.
D) The pressure remains the same.
E) The pressure decreases by a factor of two.

Answer 3

The pressure decreases by a factor of three.

Question 4

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) mmHg
C) 1.91 mmHg
D) 107 mmHg
E) mmHg

Question 5

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

Question 6

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

Question 7

Absolute zero is the point at which

A) a straight-line graph of V versus T ( ^$\circ$ 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.

Question 8

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

Question 9

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) 3950 mmHg
B) 4030 mmHg
C) 338.1 mmHg
D) 0.01255 mmHg
E) 488.0 mmHg

Question 10

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) 4.78 $\times$ 10⁵ bar
B) 4.91 $\times$ 10⁵ bar
C) 645 bar
D) 0.827 bar
E) 0.849 bar

Question 11

A particular gas exerts a pressure of 7.54 $\times$ 10⁴ Pa.What is this pressure in units of atmospheres? (1 atm = 760 mm Hg = 101.3 kPa = 1.013 bar)

A) 0.744 atm
B) 7.44 $\times$ 10⁹ atm
C) 0.764 atm
D) 0.754 atm
E) 7.64 $\times$ 10⁹ atm

Question 12

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

Question 13

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

Question 14

A flexible container is charged with 30.00 L of gas at 313K.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

Question 15

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/cm³ 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

Question 16

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

Question 17

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

Question 18

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

Question 19

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

Question 20

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) 3.48 atm
B) 2.57 $\times$ 10³ atm
C) 2.64 $\times$ 10³ atm
D) 3.39 atm
E) 3.43 atm

Question 21

If 0.357 g of CH₄ gas is introduced into an evacuated 1.75 L flask at 25 ^$\circ$ 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

Question 22

What volume of gaseous water,H₂O,has the same $\underline{\text{moles }}$ 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

Question 23

You have a 30.0 L cylinder of helium at a pressure of 132 atm and a temperature of 19 ^$\circ$ C.The He is used to fill balloons to a volume of 1.80 L at 745 mm Hg and 27 ^$\circ$ 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 $\times$ 10²
B) 1.06 $\times$ 10²
C) 4.13 $\times$ 10³
D) 7.41 $\times$ 10³
E) 2.29 $\times$ 10³

Question 24

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

Question 25

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

Question 26

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.

Question 27

The pressure of O₂ in a 15.0 L flask is 322 mm Hg at 44 ^$\circ$ 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

Question 28

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

Question 29

A balloon is filled with He gas to a volume of 2.10 L at 35 ^$\circ$ C.The balloon is placed in liquid nitrogen until its temperature reaches -196 ^$\circ$ 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

Question 30

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
B) 2 only
C) 3 only
D) 1 and 2
E) 2 and 3

Question 31

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

Question 32

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

Question 33

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) $\to$ 4 CO₂(g)+ 6 H₂O(g)

A) 7.0 mL
B) 14 mL
C) 21 mL
D) 42 mL
E) 63 mL

Question 34

A 45.0 L gas cylinder contains 988 g He at 23 ^$\circ$ 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

Question 35

What volume is occupied by 35.0 g of C₂H₂ at 471 mm Hg and 21 ^$\circ$ 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

Question 36

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)

Question 37

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.

Question 38

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

Question 39

Which of the following concerning the behavior of ideal gases is/are true?
1)Pressure is directly proportional to volume when temperature and moles of gas are held constant.
2)Pressure is directly proportional to moles of gas when temperature and volume are held constant.
3)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

Question 40

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) 1.41 $\times$ 10² mmHg
B) 1.73 $\times$ 10^-3 mmHg
C) 1.32 mmHg
D) 1.00 $\times$ 10³ mmHg
E) 5.77 $\times$ 10² mmHg

Question 41

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 KClO₃,which decomposes as follows:

A) 38.9%
B) 58.4%
C) 87.6%
D) 10.7%
E) 23.7%

Question 42

Into a 2.22-liter container at 25°C are placed 1.23 moles of O₂ 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

Question 43

The following equation represents the partial combustion of methane,CH₄.
2CH₄(g)+ 3O₂(g) $\to$ 2CO(g)+ 4H₂O(g)
At constant temperature and pressure,what is the maximum volume of carbon monoxide that can be obtained from 3.39 $\times$ 10² L of methane and 1.70 $\times$ 10² L of oxygen?

A) 5.09 $\times$ 10² L
B) 3.39 $\times$ 10² L
C) 1.19 $\times$ 10³ L
D) 1.13 $\times$ 10² L
E) 6.78 $\times$ 10² L

Question 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

Question 45

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

Question 46

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 CO₂ 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

Question 47

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

Question 48

Sodium azide decomposes rapidly to produce nitrogen gas.2 NaN₃(s) $\to$ 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 ^$\circ$ 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

Question 49

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

Question 50

When 0.5000 grams of an unknown hydrocarbon,C_xH_y,is completely combusted with excess oxygen,1.037 L CO₂ gas and is produced at 98.3 ^$\circ$ 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

Question 51

The density of H₂ gas in a rigid container is 0.117 g/L at 55 ^$\circ$ C.What is the pressure of hydrogen in the flask if it is heated to 125 ^$\circ$ 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

Question 52

Which of the following gases has the greatest density at 35 ^$\circ$ C and 450 mm Hg?

A) CH₄
B) Ar
C) N₂
D) Cl₂
E) C₃H₈

Question 53

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

Question 54

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

Question 55

What mass of O₂ is required to produce 5.00 L NO₂ at 305 K and 752 mm Hg? (R = 0.08206 L.atm/mol.K)
2 NO(g)+ O₂(g) $\to$ 2 NO₂(g)

A) 0.198 g
B) 1.58 g
C) 3.16 g
D) 5.00 g
E) 6.33 g

Question 56

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) $\to$ 2 KCl(s)+ 3 O₂(g)

A) mL
B) mL
C) mL
D) mL
E) none of these

Question 57

Ammonia gas is synthesized according to the balanced equation below.
N₂(g)+ 3 H₂(g) $\to$ 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

Question 58

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)

Question 59

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

Question 60

Aqueous hydrochloric acid reacts with magnesium to produce hydrogen gas according to the balanced equation below.
2 HCl(aq)+ Mg(s) $\to$ 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 ^$\circ$ 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

Question 61

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) 2.74 $\times$ 10² L
B) 9.13 L
C) 0.642 L
D) 1.28 L
E) 4.57 L

Question 62

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( ) $\to$ 2 H₂(g)+ O₂(g)

A) 1.47 g
B) 2.95 g
C) 4.42 g
D) 6.63 g
E) 8.84 g

Question 63

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) $\to$ 0 N₂(g)+ 2H₂O(g)

A) L
B) 22.4 L
C) L
D) L
E) L

Question 64

At STP,as the molar mass of the molecules that make up a pure gas increases,the

A) root mean square speed of the molecules increases.
B) root mean square speed of the molecules decreases.
C) root mean square speed of the molecules remains constant.
D) root mean square speed increases to a maximum,then decreases.
E) none of the above.

Question 65

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

Question 66

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) $\to$ 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

Question 67

The rate of effusion of an unknown gas was measured and found to be 14.5 mL/min.Under identical conditions,the rate of effusion of pure oxygen (O₂)gas is 17.0 mL/min.Based on this information,the identity of the unknown gas could be:

A)
B)
C)
D)
E) none of these

Question 68

Which of the following statements are postulates of the kinetic-molecular theory of gases?
1)Gas particles are in constant,random motion.
2)The distance between gas particles is large in comparison to their size.
3)The average kinetic energy of gas particles is proportional to the kelvin temperature.

A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) 1,2,and 3

Question 69

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

Question 70

The partial pressures of CH₄,N₂,and O₂ in a sample of a gas mixture were found to be 183 mmHg,493 mmHg,and 551 mmHg,respectively.Calculate the mole fraction of nitrogen.

A) 0.725
B) 0.359
C) 19.7
D) 0.449
E) 0.402

Question 71

The layer of the atmosphere closest to the Earth's surface is the ________.

A) thermosphere
B) stratosphere
C) stratopause
D) troposphere
E) mesosphere

Question 72

How long will it take 10.0 mL of Ne gas to effuse through a porous barrier if it has been observed that 125 minutes are required for 10.0 mL of Ar gas to effuse through the same barrier?

A) 1.41 min.
B) 31.9 min.
C) 63.1 min.
D) 88.8 min.
E) 176 min.

Question 73

The molar mass of an unknown gas was measured by an effusion experiment.It was found that the unknown gas effused at a rate of 3.7 $\times$ 10^-6 mol/hr,whereas nitrogen gas effused at a rate of 4.3 $\times$ 10^-6mol/hr.The molar mass of the gas is

A) 26 g/mol.
B) 33 g/mol.
C) 21 g/mol.
D) 30 g/mol.
E) 38 g/mol.

Question 74

Methane gas,CH₄,effuses through a barrier at a rate of 0.568 mL/minute.If an unknown gas effuses through the same barrier at a rate of 0.343 mL/minute,what is the molar mass of the gas?

A) 20.8 g/mol
B) 28.0 g/mol
C) 32.0 g/mol
D) 44.0 g/mol
E) 64.0 g/mol

Question 75

Carbon monoxide reacts with oxygen to form carbon dioxide.
2 CO(g)+ O₂(g) $\to$ 2 CO₂(g)
In a 1.00 L flask,4.30 atm of CO reacts with 2.50 atm of O₂.Assuming that the temperature remains constant,what is the final pressure in the flask?

A) 1.80 atm
B) 2.50 atm
C) 4.30 atm
D) 4.65 atm
E) 6.80 atm

Question 76

Calculate the root-mean-square velocity for the O₂ molecules in a sample of O₂ gas at 24.9°C.(R = 8.3145 J/K.mol)

A) 15.24 m/s
B) 139.3 m/s
C) 278.2 m/s
D) 481.9 m/s
E) 9.177 $\times$ 10²⁶ m/s

Question 77

In which of the following reactions will the pressure increase upon completion of the reaction at constant temperature?

A) C(s)+ O₂(g) $\to$ CO₂(g)
B) 2NO(g)+ O₂(g) $\to$ 2NO₂(g)
C) C₂H₆O(l)+ 3O₂(g) $\to$ 2CO₂(g)+ 3H₂O(l)
D) 4NH₃(g)+ 5O₂(g) $\to$ 4NO(g)+ 6H₂O(g)
E) Cl₂(g)+ 3F₂(g) $\to$ 2ClF₃(g)

Question 78

Place the following gases in order of increasing average velocity at 300 K: Ar,CH₄,N₂,and N₂O.

A) Ar = CH₄ = N₂ = N₂O
B) N₂O < Ar < N₂ < CH₄
C) N₂O < N₂ < CH₄ < Ar
D) Ar < N₂ < N₂O < CH₄
E) CH₄ < N₂ < N₂O < Ar

Question 79

A 10.0 L flask at 318 K contains a mixture of Ar and CH₄ with a total pressure of 1.040 atm.If the mole fraction of Ar is 0.715,what is the mass percent of Ar?

A) 13.8%
B) 68.8%
C) 71.5%
D) 82.9%
E) 86.2%

Question 80

A gaseous mixture containing 1.5 mol Ar and 3.5 mol CO₂ has a total pressure of 7.3 atm.What is the partial pressure of CO₂?

A) 2.2 atm
B) 1.4 atm
C) 17 atm
D) 5.1 atm
E) 7.3 atm