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) B) and E)
G) A) and E)

Question 2

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

Accepted Answer

At STP, the pressure...

Question 3

Given that pressure has dimensions of force * area; that force has dimensions of mass * acceleration; and that the S.I. unit of pressure is the pascal, what is 1 pascal in terms of S.I. base units?

Accepted Answer

A)   1 Pa = 1000 g/cm*s2
B)   1 Pa = 1 g/m*s2
C)   1 Pa = 10¯3 kg*m/s2
D)   1 Pa = 1 kg*m/s2
E)   1 Pa = 1 kg/m*s2F) A) and C)
G) A) and B)

Question 4

For real gases, PV < nRT, always.

Accepted Answer

A) True 
 B)False

Question 5

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?

Accepted Answer

A)   10 torr
B)   50 torr
C)   100 torr
D)   200 torr
E)   1000 torrF) C) and E)
G) B) and E)

Question 6

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

Accepted Answer

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 F) A) and B)
G) C) and D)

Question 7

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) C) and D)
G) B) and D)

Question 8

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  °\degree° 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 is correct. F) None of the above
G) C) and D)

Question 9

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

Accepted Answer

A)   95.0 °\degree° C
B)   85.1 °\degree° C
C)   77.2 °\degree° C
D)   72.9 °\degree° C
E)   65.2 °\degree° C F) D) and E)
G) B) and D)

Question 10

"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.

Accepted Answer

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

Question 11

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

Accepted Answer

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

Question 12

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 13

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?

Accepted Answer

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

Question 14

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

Accepted Answer

A)   32.1 kPa
B)   46.6 kPa
C)   657 kPa
D)   953 kPa
E)   None of these choices is correct since the pressure would have to be negative. F) A) and B)
G) B) and D)

Question 15

Use plots of PV/nRT versus P to show the behavior of an ideal gas and of typical real gases. Label the axes and show their scales.

Accepted Answer

Ideal gas: the plot is a horizontal line...

Question 16

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 °\degree° C.

Accepted Answer

A)   20 m/s
B)   120 m/s
C)   210 m/s
D)   260 m/s
E)   4.4 * 104 m/s F) B) and C)
G) D) and E)

Question 17

A sample of ammonia gas at 65.5 °\degree° C and 524 torr has a volume of 15.31 L. What is its volume when the temperature is -15.8 °\degree° 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)   None of these choices is correct since the volume would have to be negative. F) B) and E)
G) A) and D)

Question 18

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

Accepted Answer

A)   0.0176 g/L
B)   0.0250 g/L
C)   0.0561 g/L
D)   1.78 g/L
E)   181. g/LF) B) and E)
G) A) and E)

Question 19

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 20

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)   →\rightarrow→ 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 H2 F) B) and C)
G) A) and E)

Exam 5: Gases and the Kinetic-Molecular Theory

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

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedAt STP, the pressure...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

Given that pressure has dimensions of force * area; that force has dimensions of mass * acceleration; and that the S.I. unit of pressure is the pascal, what is 1 pascal in terms of S.I. base units?

Correct AnswerverifiedShow Answer

"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.

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

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

Correct AnswerverifiedShow Answer

Use plots of PV/nRT versus P to show the behavior of an ideal gas and of typical real gases. Label the axes and show their scales.

Correct AnswerverifiedIdeal gas: the plot is a horizontal line...View AnswerShow 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) →\rightarrow→ MgCl2(aq) + H2(g)

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 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

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

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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 °\degree° C.

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

For real gases, PV < nRT, always.

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 °\degree° C, what fraction of the container's volume is occupied by the molecules themselves?

Correct AnswerverifiedShow Answer

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

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
At STP, the pressure...
View Answer

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

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified
Ideal gas: the plot is a horizontal line...
View 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) $\rightarrow$ MgCl₂(aq) + H₂(g)

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified

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 $\degree$ C.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

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 $\degree$ C, what fraction of the container's volume is occupied by the molecules themselves?

Correct Answer
verified