Question 1

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 2

A gas consists of 85.7 percent carbon and 14.3 percent hydrogen, by weight. A sample of this gas weighing 0.673 g occupies 729 mL at a pressure of 720.0 mmHg and a temperature of 77°C. Calculate its empirical and molecular formulas.

Accepted Answer

A)  CH, C 2H 2
B)  CH 2, C 2H 4
C)  CH 2, C 3H 6
D)  CH 3, C 2H 6
E)  CH 4, CH 4F) B) and E)
G) C) and D)

Question 3

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

Accepted Answer

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

Question 4

A ballerina weighs 103 lbs and is up on her toes with only 10.0 cm2 of her slippers in contact with the floor. What pressure is she exerting on the floor?

Accepted Answer

A)  4.59 × 10 5 Pa
B)  4.59 × 10 3 Pa
C)  4.59 × 10 1 Pa
D)  4.59 × 10 −1 Pa
E)  4.59 × 10 −3 PaF) A) and E)
G) D) and E)

Question 5

Mineral oil can be used in place of mercury in manometers 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)

Accepted Answer

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 oilF) B) and E)
G) B) and D)

Question 6

For a pure gas sample, the average kinetic energy is also the most probable kinetic energy.

Accepted Answer

A) True 
 B)False

Question 7

According to the postulates of kinetic-molecular theory, the average kinetic energy of gas molecules is proportional to the absolute temperature.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following gases effuses most rapidly?

Accepted Answer

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

Question 9

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?

Accepted Answer

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

Question 10

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.

Accepted Answer

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

Question 11

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) None of the above
G) C) and E)

Question 12

The rate of diffusion of a gas is inversely proportional to its molar mass.

Accepted Answer

A) True 
 B)False

Question 13

Helium gas is being pumped into a rigid container at a constant temperature. As a result, the pressure of helium in the container is increasing. Select the one correct statement below.

Accepted Answer

A)  As the pressure increases, helium atoms move faster, on average.
B)  As the pressure increases, helium atoms move more slowly, on average.
C)  As the pressure increases, the volume of the container must decrease.
D)  As the pressure increases, helium atoms stay closer to the wall of the container, on average.
E)  As the pressure increases, there are more collisions of helium atoms with the container wall.F) A) and B)
G) B) and E)

Question 14

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? (Pwater = 24 torr at 25°C)

Accepted Answer

A)  0.00765 g
B)  0.0154 g
C)  0.0159 g
D)  0.0164 g
E)  0.159 gF) All of the above
G) C) and D)

Question 15

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

Accepted Answer

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.F) D) and E)
G) B) and D)

Question 16

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) C) and D)

Question 17

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.

Accepted Answer

A)  32.1 kPa
B)  46.6 kPa
C)  657 kPa
D)  953 kPa
E)  Not possible, since the pressure would have to be negativeF) All of the above
G) C) and D)

Question 18

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

Accepted Answer

A)  such high pressures cannot be accurately measured.
B)  CO 2 will condense to a liquid at 200 atm pressure.
C)  gas phase collisions prevent CO 2 molecules from colliding with the walls of the container.
D)  of attractive intermolecular forces between CO 2 molecules.
E)  the volume occupied by the CO 2 molecules themselves becomes significant.F) B) and D)
G) C) and D)

Question 19

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

Accepted Answer

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

Question 20

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) A) and B)
G) None of the above

Exam 5: Gases and the Kinetic-Molecular Theory

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

According to the postulates of kinetic-molecular theory, the average kinetic energy of gas molecules is proportional to the absolute temperature.

Correct AnswerverifiedShow Answer

Helium gas is being pumped into a rigid container at a constant temperature. As a result, the pressure of helium in the container is increasing. Select the one correct statement below.

Correct AnswerverifiedShow Answer

For a pure gas sample, the average kinetic energy is also the most probable kinetic energy.

Correct AnswerverifiedShow Answer

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? (Pwater = 24 torr at 25°C)

Correct AnswerverifiedShow Answer

The rate of diffusion of a gas is inversely proportional to its molar mass.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A gas consists of 85.7 percent carbon and 14.3 percent hydrogen, by weight. A sample of this gas weighing 0.673 g occupies 729 mL at a pressure of 720.0 mmHg and a temperature of 77°C. Calculate its empirical and molecular formulas.

Correct AnswerverifiedShow Answer

The ozone layer is important because

Correct AnswerverifiedShow Answer

A ballerina weighs 103 lbs and is up on her toes with only 10.0 cm2 of her slippers in contact with the floor. What pressure is she exerting on the floor?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following gases effuses most rapidly?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

Mineral oil can be used in place of mercury in manometers 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)

Correct AnswerverifiedShow Answer

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.

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 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 AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

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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)

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A ballerina weighs 103 lbs and is up on her toes with only 10.0 cm² of her slippers in contact with the floor. What pressure is she exerting on the floor?

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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

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