Question 1

A weather balloon was initially at a pressure of 0.950 atm, and its volume was 35.0 L. The pressure decreased to 0.750 atm, without loss of gas or change in temperature. What was the change in the volume?

Accepted Answer

A)   increased by 44.3 L
B)   increased by 9.3 L
C)   increased by 7.4 L
D)   decreased by 27.6 L
E)   decreased by 7.4 LF) All of the above
G) B) and E)

Question 2

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

Accepted Answer

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

Question 3

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

Accepted Answer

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

Question 4

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

Accepted Answer

A) True 
 B)False

Question 5

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?

Accepted Answer

A)   3.69 L
B)   11.6 L
C)   20.2 L
D)   63.5 L
E)   not possible, since the volume would have to be negativeF) A) and C)
G) C) and E)

Question 6

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?

Accepted Answer

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

Question 7

When a closed-ended manometer is used for pressure measurements, and the closed end is under vacuum, the level of manometer liquid in the closed arm can never be lower than that in the other arm.

Accepted Answer

A) True 
 B)False

Question 8

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, C2H2
B)   CH2, C2H4
C)   CH2, C3H6
D)   CH3, C2H6
E)   CH4, CH4F) C) and D)
G) A) and C)

Question 9

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

Accepted Answer

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

Question 10

For a gas obeying Boyle's Law, a plot of V versus 1/P will give a straight line passing through the origin.

Accepted Answer

A) True 
 B)False

Question 11

At a temperature of absolute zero, the volume of an ideal gas is zero.

Accepted Answer

A) True 
 B)False

Question 12

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.

Accepted Answer

A)   CHCl3
B)   CH2Cl2
C)   C2H2Cl2
D)   C2H3Cl
E)   CCl4F) A) and B)
G) B) and C)

Question 13

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)  → MgCl2(aq)  + H2(g)

Accepted Answer

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 H2F) All of the above
G) C) and D)

Question 14

The volume of a single molecule of water is 2.99 × 10-23 mL. For a sample of gaseous water at 1.00 atm and 150°C, what fraction of the container's volume is occupied by the molecules themselves?

Accepted Answer

A)   5.2 × 10-7
B)   4.5 × 10-5
C)   5.2 × 10-4
D)   5.2 × 10-1
E)   None of these choices are correct.F) C) and E)
G) A) and E)

Question 15

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

Accepted Answer

A)   46.91 torr
B)   267.4 torr
C)   351.8 torr
D)   3612 torr
E)   27090 torrF) A) and E)
G) C) and E)

Question 16

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?

Accepted Answer

A)   9.00 × 10-2 atm
B)   0.933 atm
C)   1.11 atm
D)   1.70 atm
E)   11.1 atmF) A) and D)
G) A) and E)

Question 17

Select the statement that does not apply to an ideal gas.

Accepted Answer

A)   There are no attractive forces between the gas molecules.
B)   There are strong repulsive forces between the gas molecules.
C)   The volume occupied by the molecules is negligible compared to the container volume.
D)   The gas behaves according to the ideal gas equation.
E)   The average kinetic energy of the molecules is proportional to the absolute temperature.F) A) and B)
G) C) and D)

Question 18

Linolenic acid (C18H30O2)  can be hydrogenated to stearic acid by reacting it with hydrogen gas according to the equation: C18H30O2 + 3H2 → C18H36O2
What volume of hydrogen gas, measured at STP, is required to react with 10.5 g of linolenic acid in this reaction?

Accepted Answer

A)   2.53 L
B)   1.69 L
C)   1.27 L
D)   845 mL
E)   422 mLF) D) and E)
G) C) and D)

Question 19

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) A) and E)
G) C) and E)

Question 20

Which of the following changes will not affect the total pressure of gas in a container, assuming all other factors remain constant?

Accepted Answer

A)   The frequency of collisions of molecules with the walls is increased.
B)   The average velocity of the molecules is lowered.
C)   The temperature of the sample is altered.
D)   Half of the molecules are replaced by an equal number of molecules of a gas with a different molecular weight.
E)   The total number of molecules is altered.F) None of the above
G) All of the above

Exam 5: Gases and the Kinetic-Molecular Theory

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

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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

When a closed-ended manometer is used for pressure measurements, and the closed end is under vacuum, the level of manometer liquid in the closed arm can never be lower than that in the other arm.

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Select the statement that does not apply to an ideal gas.

Correct AnswerverifiedShow Answer

A weather balloon was initially at a pressure of 0.950 atm, and its volume was 35.0 L. The pressure decreased to 0.750 atm, without loss of gas or change in temperature. What was the change in the volume?

Correct AnswerverifiedShow Answer

Linolenic acid (C18H30O2) can be hydrogenated to stearic acid by reacting it with hydrogen gas according to the equation: C18H30O2 + 3H2 → C18H36O2 What volume of hydrogen gas, measured at STP, is required to react with 10.5 g of linolenic acid in this reaction?

Correct AnswerverifiedShow Answer

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) → MgCl2(aq) + H2(g)

Correct AnswerverifiedShow Answer

For a gas obeying Boyle's Law, a plot of V versus 1/P will give a straight line passing through the origin.

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

Which of the following changes will not affect the total pressure of gas in a container, assuming all other factors remain constant?

Correct AnswerverifiedShow Answer

The volume of a single molecule of water is 2.99 × 10-23 mL. For a sample of gaseous water at 1.00 atm and 150°C, what fraction of the container's volume is occupied by the molecules themselves?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

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

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?

Correct AnswerverifiedShow Answer

At a temperature of absolute zero, the volume of an ideal gas is zero.

Correct AnswerverifiedShow Answer

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Linolenic acid (C₁₈H₃₀O₂) can be hydrogenated to stearic acid by reacting it with hydrogen gas according to the equation: C₁₈H₃₀O₂ + 3H₂ → C₁₈H₃₆O₂ What volume of hydrogen gas, measured at STP, is required to react with 10.5 g of linolenic acid in this reaction?

Correct Answer
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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) → MgCl₂(aq) + H₂(g)

Correct Answer
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The volume of a single molecule of water is 2.99 × 10^-23 mL. For a sample of gaseous water at 1.00 atm and 150°C, what fraction of the container's volume is occupied by the molecules themselves?

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