Deck 5: Gases and the Kinetic-Molecular Theory

Question 1

Which of the lines on the figure below is the best representation of the relationship between the volume and the number of moles of a gas,measured at constant temperature and pressure?

A)a
B)b
C)c
D)d
E)e

Answer 1

c

Question 2

The pressure of hydrogen sulfide gas in a container is 35,650 Pa.What is this pressure in torr?

A)46.91 torr
B)267.4 torr
C)351.8 torr
D)3612 torr
E)27,090 torr

Answer 2

267.4 torr

Question 3

"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'
B)Boyle's
C)Amontons'
D)Avogadro's
E)Dalton's

Answer 3

Charles'

Question 4

The air pressure in a volleyball is 75 psi.What is this pressure in torr?

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

Question 5

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 6

Hydrogen gas exerts a pressure of 466 torr in a container.What is this pressure in atmospheres?

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

Question 7

Mineral oil can be used in place of mercury in certain pressure-measuring instruments when small pressure changes are to be measured.What is the pressure of an oxygen sample in mm of mineral oil if its pressure is 28.5 mm Hg? (d of mineral oil = 0.88 g/mL;d of Hg = 13.5 g/mL)

A)1.9 mm mineral oil
B)15 mm mineral oil
C)32 mm mineral oil
D)380 mm mineral oil
E)440 mm mineral oil

Question 8

"The total pressure in a mixture of unreacting gases is equal to the sum of the partial pressures of the individual gases" is a statement of __________________ Law.

A)Charles'
B)Graham's
C)Boyle's
D)Avogadro's
E)Dalton's

Question 9

"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'
B)Boyle's
C)Amontons'
D)Avogadro's
E)Dalton's

Question 10

A sample container of carbon monoxide occupies a volume of 435 mL at a pressure of 785 torr and a temperature of 298 K.What would its temperature be if the volume were changed to 265 mL at a pressure of 785 torr?

A)182 K
B)298 K
C)387 K
D)489 K
E)538 K

Question 11

A sample of oxygen gas has its absolute temperature halved while the pressure of the gas remained constant.If the initial volume is 400 mL,what is the final volume?

A)20 mL
B)133 mL
C)200 mL
D)400 mL
E)800 mL

Question 12

"The rate of effusion of a gas is inversely proportional to the square root of its molar mass" is a statement of _________________ Law.

A)Charles'
B)Graham's
C)Dalton's
D)Avogadro's
E)Boyle's

Question 13

Which of the lines on the figure below is the best representation of the relationship between the volume of a gas and its pressure,other factors remaining constant?

A)a
B)b
C)c
D)d
E)e

Question 14

The pressure of sulfur dioxide in a container is 159 kPa.What is this pressure in atmospheres?

A)0.209 atm
B)0.637 atm
C)1.57 atm
D)21.2 atm
E)15,900 atm

Question 15

Which of the lines on the figure below is the best representation of the relationship between the volume of a gas and its Celsius temperature,other factors remaining constant?

A)a
B)b
C)c
D)d
E)e

Question 16

Which of the lines on the figure below is the best representation of the relationship between the volume of a gas and its absolute temperature,other factors remaining constant?

A)a
B)b
C)c
D)d
E)e

Question 17

A sample of the inert gas krypton has its pressure tripled while its temperature remained constant.If the original volume is 12 L,what is the final volume?

A)4.0 L
B)6.0 L
C)9 L
D)36 L
E)48 L

Question 18

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 19

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 20

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

Question 21

A 500-mL sample of argon at 800 torr has its absolute temperature quadrupled.If the volume remains unchanged,what is the new pressure?

A)200 torr
B)400 torr
C)800 torr
D)2400 torr
E)3200 torr

Question 22

A sample of methane gas,CH₄(g),occupies a volume of 60.3 L at a pressure of 469 torr and a temperature of 29.3°C.What would be its temperature at a pressure of 243 torr and volume of 60.3 L?

A)-116.5°C
B)15.2°C
C)15.5°C
D)57.7°C
E)310.6°C

Question 23

A sample of ammonia gas at 65.5°C and 524 torr has a volume of 15.31 L.What is its volume when the temperature is -15.8°C and its pressure is 524 torr?

A)3.69 L
B)11.6 L
C)20.2 L
D)63.5 L
E)It is not possible,since the volume would have to be negative.

Question 24

Ima Chemist found the density of Freon-11 (CFCl₃)to be 5.58 g/L under her experimental conditions.Her measurements showed that the density of an unknown gas was 4.38 g/L under the same conditions.What is the molar mass of the unknown?

A)96.7 g/mol
B)108 g/mol
C)127 g/mol
D)165 g/mol
E)175 g/mol

Question 25

A 0.850-mole sample of nitrous oxide,a gas used as an anesthetic by dentists,has a volume of 20.46 L at 123°C and 1.35 atm.What would be its volume at 468°C and 1.35 atm?

A)5.38 L
B)10.9 L
C)19.0 L
D)38.3 L
E)77.9 L

Question 26

A 750-mL sample of hydrogen exerts a pressure of 822 torr at 325 K.What pressure does it exert if the temperature is raised to 475 K at constant volume?

A)188 torr
B)562 torr
C)1.11 $\times$ 10³ torr
D)1.20 $\times$ 10³ torr
E)1.90 $\times$ 10³ torr

Question 27

Calculate the pressure of a helium sample at -207.3°C and 768 mL if it exerts a pressure of 175 kPa at 25.0°C and 925 mL.

A)32.1 kPa
B)46.6 kPa
C)657 kPa
D)953 kPa
E)It is not possible,since the pressure would have to be negative.

Question 28

A carbon dioxide sample weighing 44.0 g occupies 32.68 L at 65°C and 645 torr.What is its volume at STP?

A)22.4 L
B)31.1 L
C)34.3 L
D)35.2 L
E)47.7 L

Question 29

A flask with a volume of 3.16 L contains 9.33 grams of an unknown gas at 32.0°C and 1.00 atm.What is the molar mass of the gas?

A)7.76 g/mol
B)66.1 g/mol
C)74.0 g/mol
D)81.4 g/mol
E)144 g/mol

Question 30

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?

A)0.271 mol
B)2.27 mol
C)3.69 mol
D)206 mol
E)227 mol

Question 31

Dr.I.M.A.Brightguy adds 0.1727 g of an unknown gas to a 125-mL flask.If Dr.B finds the pressure to be 736 torr at 20.0°C,is the gas likely to be methane,CH₄,nitrogen,N₂,oxygen,O₂,neon,Ne,or argon,Ar?

A)CH₄
B)N₂
C)Ne
D)Ar
E)O₂

Question 32

Calculate the temperature of an argon sample at 55.4 kPa and 18.6 L if it occupies 25.8 L at 75.0°C and 41.1 kPa.

A)95.0°C
B)85.1°C
C)77.2°C
D)72.9°C
E)65.2°C

Question 33

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?

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

Question 34

Nitrogen dioxide is a red-brown gas that is responsible for the color of photochemical smog.A sample of nitrogen dioxide has a volume of 28.6 L at 45.3°C and 89.9 kPa.What is its volume at STP?

A)21.8 L
B)27.6 L
C)29.6 L
D)37.6 L
E)153 L

Question 35

What are the conditions of STP?

A)0 K and l atm
B)273.15 K and 760 torr
C)0°C and 760 atm
D)273.15°C and 760 torr
E)None of these choices is correct.

Question 36

What is the density of carbon dioxide gas at -25.2°C and 98.0 kPa?

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 37

What is the pressure in a 7.50-L flask if 0.15 mol of carbon dioxide is added to 0.33 mol of oxygen? The temperature of the mixture is 48.0°C.

A)0.252 atm
B)0.592 atm
C)1.69 atm
D)3.96 atm
E)4.80 atm

Question 38

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?

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

Question 39

A compressed gas cylinder containing 1.50 mol 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?

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

Question 40

Assuming ideal behavior,what is the density of argon gas at STP,in g/L?

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 41

Which of the following gases effuses most rapidly?

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

Question 42

Freon-12,CF₂Cl₂,which has been widely used in air conditioning systems,is considered a threat to the ozone layer in the stratosphere.Calculate the root-mean-square velocity of Freon-12 molecules in the lower stratosphere where the temperature is -65°C.

A)20 m/s
B)120 m/s
C)210 m/s
D)260 m/s
E)4.4 $\times$ 10⁴ m/s

Question 43

Calculate the root-mean-square speed of methane,CH₄ (g),at 78°C.

A)23 m/s
B)350 m/s
C)550 m/s
D)667 m/s
E)740 m/s

Question 44

A gas mixture,with a total pressure of 300.torr,consists of equal masses of Ne (atomic weight 20. )and Ar (atomic weight 40. ).What is the partial pressure of Ar,in torr?

A)75 torr
B)100.torr
C)150.torr
D)200.torr
E)None of these choices is correct.

Question 45

An unknown liquid is vaporized in a 273-mL flask by immersion in a water bath at 99°C.The barometric pressure is 753 torr.If the mass of the substance's vapor retained in the flask is 1.362 g,what is its molar mass?

A)20.4 g/mol
B)40.9 g/mol
C)112 g/mol
D)154 g/mol
E)184 g/mol

Question 46

If 0.750 L of argon at 1.50 atm and 177°C and 0.235 L of sulfur dioxide at 95.0 kPa and 63.0°C are added to a 1.00-L flask and the flask's temperature is adjusted to 25.0°C,what is the resulting pressure in the flask?

A)0.0851 atm
B)0.244 atm
C)0.946 atm
D)1.74 atm
E)1.86 atm

Question 47

Small quantities of hydrogen can be prepared by the addition of hydrochloric acid to zinc.A sample of 195 mL of hydrogen was collected over water at 25°C and 753 torr.What mass of hydrogen was collected? (P_water = 24 torr at 25°C)

A)0.00765 g
B)0.0154 g
C)0.0159 g
D)0.0164 g
E)0.159 g

Question 48

A gas mixture consists of equal masses of methane (molecular weight 16.0)and argon (atomic weight 40.0).If the partial pressure of argon is 200.torr,what is the pressure of methane,in torr?

A)80.0 torr
B)200.torr
C)256 torr
D)500.torr
E)556 torr

Question 49

At what temperature in Kelvin is the root mean square speed of helium atoms (atomic weight = 4.00)equal to that of oxygen molecules (molecular weight = 32.00)at 300.K?

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

Question 50

A compound composed of carbon,hydrogen,and chlorine effuses through a pinhole 0.411 times as fast as neon.Select the correct molecular formula for the compound.

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

Question 51

Magnesium metal (0.100 mol)and a volume of aqueous hydrochloric acid that contains 0.500 mol of HCl are combined and react to completion.How many liters of hydrogen gas,measured at STP,are produced?
Mg(s)+ 2HCl(aq) $\to$ MgCl₂(aq)+ H₂(g)

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

Question 52

Which of the following gases will be the slowest to diffuse through a room?

A)methane,CH₄
B)hydrogen sulfide,H₂S
C)carbon dioxide,CO₂
D)water,H₂O
E)neon,Ne

Question 53

Arrange the following gases in order of increasing rate of effusion.

A)Ar < HCl 3 < C₂H₆
B)C₂H₆ < PH₃ < HCl < Ar
C)Ar < PH₃ < C₂H₆ < HCl
D)C₂H₆ < HCl < PH₃ < Ar
E)Ar 3 < HCl < C₂H₆

Question 54

Select the gas with the highest average kinetic energy per mole at 298 K.

A)O₂
B)CO₂
C)H₂O
D)H₂
E)All have the same average kinetic energy.

Question 55

Lithium oxide is an effective absorber of carbon dioxide and can be used to purify air in confined areas such as space vehicles.What volume of carbon dioxide can be absorbed by 1.00 kg of lithium oxide at 25°C and 1.00 atm?
Li₂O(aq)+ CO₂(g) $\to$ Li₂CO₃(s)

A)687 mL
B)819 mL
C)687 L
D)819 L
E)22.4 L

Question 56

Hydrochloric acid is prepared by bubbling hydrogen chloride gas through water.What is the concentration of a solution prepared by dissolving 225 L of HCl(g)at 37°C and 89.6 kPa in 5.25 L of water?

A)1.49 M
B)1.66 M
C)7.82 M
D)12.5 M
E)16.6 M

Question 57

A 3.0-L sample of helium was placed in a 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 58

Select the gas with the largest root-mean-square molecular speed at 25°C.

A)NH₃
B)CO
C)H₂
D)SF₆
E)All the gases have the same root-mean-square molecular speed at 25°C.

Question 59

Methane,CH₄(g),reacts with steam to give synthesis gas,a mixture of carbon monoxide and hydrogen,which is used as starting material for the synthesis of a number of organic and inorganic compounds.
CH₄(g)+ H₂O(g) $\to$ CO(g)+ H₂(g)[unbalanced]
What mass of hydrogen is formed if 275 L of methane (measured at STP)is converted to synthesis gas?

A)12.3 g
B)24.7 g
C)37.1 g
D)49.4 g
E)74.2 g

Question 60

Hydrogen peroxide was catalytically decomposed and 75.3 mL of oxygen gas was collected over water at 25°C and 742 torr.What mass of oxygen was collected? (P_water = 24 torr at 25°C)

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

Question 61

Nitrogen will behave most like an ideal gas

A)at high temperature and high pressure.
B)at high temperature and low pressure.
C)at low temperature and high pressure.
D)at low temperature and low pressure.
E)at intermediate (moderate)temperature and pressure.

Question 62

Use the van der Waals equation for real gases to calculate the pressure exerted by 1.00 mole of ammonia at 27°C in a 750-mL container.(a = 4.17 L²·atm/mol²,b = 0.0371 L/mol)

A)23.2 atm
B)27.1 atm
C)32.8 atm
D)42.0 atm
E)32.8 torr

Question 63

Dry air is approximately 78% nitrogen,21% oxygen and 1% argon,by number of molecules.What is the partial pressure of oxygen in a sample of dry air,if atmospheric pressure is 751 torr?

Question 64

A 1.00-L sample of a pure gas weighs 0.785 g and is at 0.965 atm and 29.2°C.
a.What is the molar mass of the gas?
b.If the volume and temperature are kept constant while 0.400 g of the same gas are added to that already in the container,what will the new pressure be?

Question 65

Briefly state the conditions corresponding to STP (standard temperature and pressure).

Question 66

A 255-mL gas sample weighing 0.292 g is at 52,810 Pa and 127°C.
a.How many moles of gas are present?
b.What is the molar mass of the gas?

Question 67

Calculate the density in g/L of gaseous SF₆ at 50.0°C and 650.torr.

Question 68

The temperature of the carbon dioxide atmosphere near the surface of Venus is 475°C.Calculate the average kinetic energy per mole of carbon dioxide molecules on Venus.

A)2520 J/mol
B)4150 J/mol
C)5920 J/mol
D)9330 J/mol
E)5920 kJ/mol

Question 69

State Boyle's Law and illustrate it with a graph,using standard x-y coordinate axes.Be sure to label the axes unambiguously with the correct gas variables.

Question 70

State Avogadro's Law.

Question 71

In the fermentation process,yeast converts glucose to ethanol and carbon dioxide.What volume of carbon dioxide,measured at 745 torr and 25.0°C,can be produced by the fermentation of 10.0 g of glucose?
C₆H₁₂O₆(aq) $\to$ 2C₂H₅OH(aq)+ 2CO₂(g)

Question 72

Aluminum metal shavings (10.0 g)are placed in 100.mL of 6.00 M hydrochloric acid.What is the maximum volume of hydrogen,measured at STP,which can be produced?
2Al(s)+ 6HCl(aq) $\to$ 2AlCl₃(aq)+ 3H₂(g)

Question 73

A 3.60-L gas sample is at a pressure of 95.5 kPa and a temperature of 25.0°C.
a.Calculate the volume occupied by the gas at STP,assuming it behaves ideally.
b.If the gas sample weighs 6.10 g,calculate the molar mass of the gas.

Question 74

Starting from the Ideal Gas Equation,derive an equation corresponding to Charles' Law,stating all important assumptions or conditions.

Question 75

At moderate pressures (~ 200 atm),the measured pressure exerted by CO₂ gas is less than that predicted by the ideal gas equation.This is mainly because

A)such high pressures cannot be accurately measured.
B)CO₂ will condense to a liquid at 200 atm pressure.
C)gas phase collisions prevent CO₂ molecules from colliding with the walls of the container.
D)of attractive intermolecular forces between CO₂ molecules.
E)the volume occupied by the CO₂ molecules themselves becomes significant.

Question 76

A 1.30-L sample of argon gas is at 1.02 atm and 21.5°C.
a.What mass of argon is in the container?
b.If the temperature is raised to 500.0°C while the volume remains constant,calculate the new pressure,in atmospheres.

Question 77

At very high pressures (~ 1000 atm),the measured pressure exerted by real gases is greater than that predicted by the ideal gas equation.This is mainly because

A)such high pressures cannot be accurately measured.
B)real gases will condense to form liquids at 1000 atm pressure.
C)gas phase collisions prevent molecules from colliding with the walls of the container.
D)of attractive intermolecular forces between gas molecules.
E)the volume occupied by the gas molecules themselves becomes significant.

Question 78

An oxygen sample of 1.62 L is at 92.3 kPa and 30.0°C.
a.What is the pressure of oxygen,in torr?
b.What volume would the oxygen occupy if the pressure were 120.0 kPa and the temperature were 0.0°C?
c.How many moles of oxygen are in the sample?

Question 79

Chlorofluorocarbons are important air pollutants implicated in global warming and ozone depletion.How fast does the chlorofluorocarbon CF₂Cl₂ diffuse relative to N₂,the main component of the atmosphere? In other words,calculate the ratio of diffusion rates:

Question 80

State Charles' Law and illustrate it with a graph,using standard x-y coordinate axes.Be sure to label the axes unambiguously with the correct gas variables.