Question 1

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?

Accepted Answer

A)   -230.
B)   230.
C)   530.
D)   790.
E)   None of these choices are correct.F) A) and B)
G) C) and D)

Question 2

If the molecular mass of a gas increases by a factor of 4 at constant temperature, its rms speed will

Accepted Answer

A)   decrease by a factor of 4.
B)   increase by a factor of 4.
C)   decrease by a factor of 16.
D)   increase by a factor of 16.
E)   decrease by a factor of 2.F) A) and B)
G) A) and C)

Question 3

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?

Accepted Answer

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

Question 4

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?

Accepted Answer

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

Question 5

Which of the following gases effuses most rapidly?

Accepted Answer

A)   Nitrogen
B)   Oxygen
C)   Hydrogen chloride
D)   Ammonia
E)   Carbon monoxideF) A) and B)
G) A) and E) D

Question 6

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

Accepted Answer

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

Question 7

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

Accepted Answer

A)   520 torr
B)   562 torr
C)   3900 torr
D)   7600 torr
E)   75000 torrF) A) and B)
G) A) and C)

Question 8

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?

Accepted Answer

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

Question 9

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

Accepted Answer

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

Question 10

According to the kinetic theory of gases, in a collision between two molecules the kinetic energy of one molecule will decrease by the same amount that the kinetic energy of the other one increases.

Accepted Answer

A) True 
 B)False

Question 11

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?

Accepted Answer

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

Question 12

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?

Accepted Answer

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

Question 13

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?

Accepted Answer

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

Question 14

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?

Accepted Answer

A)   a
B)   b
C)   c
D)   d
E)   eF) A) and B)
G) B) and D)

Question 15

The ozone layer is important because

Accepted Answer

A)   ozone absorbs low energy radiation which warms the troposphere.
B)   ozone purifies the atmosphere by reacting with excess fluorocarbons.
C)   ozone absorbs ultraviolet radiation.
D)   ozone reflects high energy radiation such as X-rays and gamma rays.
E)   humans need to breathe air containing some ozone.F) A) and B)
G) A) and C)

Question 16

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.

Accepted Answer

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

Question 17

Mercury is 13.6 times as dense as liquid water. What would be the reading of a water-filled barometer at normal atmospheric pressure, 760. mmHg?

Accepted Answer

A)   1.03 × 103 torr
B)   1.03 × 103 Pa
C)   1.03 × 103 mm height of water column
D)   1.03 × 103 cm height of water column
E)   13.6 atmF) A) and C)
G) B) and D)

Question 18

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

Accepted Answer

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

Question 19

"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.

Accepted Answer

A)   Charles's
B)   Graham's
C)   Boyle's
D)   Avogadro's
E)   Dalton'sF) None of the above
G) A) and E)

Question 20

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

Accepted Answer

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

Exam 5: Gases and the Kinetic-Molecular Theory

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?

Correct AnswerverifiedShow Answer

If the molecular mass of a gas increases by a factor of 4 at constant temperature, its rms speed will

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedA

Which of the following gases effuses most rapidly?

Correct AnswerverifiedD

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

According to the kinetic theory of gases, in a collision between two molecules the kinetic energy of one molecule will decrease by the same amount that the kinetic energy of the other one increases.

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedD

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

The ozone layer is important because

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

Mercury is 13.6 times as dense as liquid water. What would be the reading of a water-filled barometer at normal atmospheric pressure, 760. mmHg?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

"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.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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D

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

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

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D

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