Question 1

A 259.6-L cylinder contains 63.5% He(g)  and 36.5% Kr(g)  by mass at 22.0°C and 1.25 atm total pressure. What is the mass of He in this container?

Accepted Answer

A)   30.0 g
B)   52.2 g
C)   82.2 g
D)   700 g
E)   34.1 gF) A) and B)
G) A) and E)

Question 2

A mixture of KCl and KClO3 weighing 1.80 g was heated; the dry O2 generated occupied 1.40  102 mL at STP. What percent of the original mixture was KClO3? KClO3 decomposes as follows: 2KClO3(s)   2KCl(s)  + 3O2(g)

Accepted Answer

A)   37.2%
B)   72.6%
C)   42.6%
D)   63.8%
E)   28.4%F) A) and B)
G) None of the above

Question 3

What volume of carbon dioxide measured at STP will be formed by the reaction of 1.30 mol of oxygen with 9.00  10-1 mol of ethyl alcohol (CH3CH2OH) ?

Accepted Answer

A)   91.9 L
B)   8.70 L
C)   28.0 L
D)   19.4 L
E)   40.3 LF) All of the above
G) A) and C)

Question 4

Body temperature is about 308 K. On a cold day, what volume of air at 273 K must a person with a lung capacity of 2.00 L breathe in to fill the lungs?

Accepted Answer

A)   1.13 L
B)   2.26 L
C)   1.77 L
D)   3.54 L
E)   none of theseF) A) and E)
G) B) and D)

Question 5

Consider three 1.0-L flasks at STP. Flask A contains Ar gas, flask B contains Kr gas, and flask C contains H2 gas. In which flask do the gas particles have the highest average velocity?

Accepted Answer

A)   flask A
B)   flask B
C)   flask C
D)   The gas particles in all the flasks have the same average velocity.
E)   The gas particles in two of the flasks have the same average velocity.F) B) and D)
G) C) and D)

Question 6

Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N2 gas, and flask C contains O2 gas. In which flask do the molecules have the greatest kinetic energy?

Accepted Answer

A)   flask A
B)   flask B
C)   flask C
D)   The molecules in all the flasks have the same kinetic energy.
E)   The molecules in two of the flasks have the same kinetic energy.F) None of the above
G) C) and E)

Question 7

Suppose a sealed flask contains 1.0 L of oxygen gas that is completely converted to ozone (O3) at the same temperature. Calculate the ratio of the new pressure to the original pressure and the ratio of the number of impacts of ozone molecules with the walls of the container to the number of impacts of oxygen molecules with the walls of the container.

Accepted Answer

Question 8

At 1000°C and 10. torr, the density of a certain element in the gaseous state is 2.9  10-3 g/L. The element is

Accepted Answer

A)   Ne.
B)   Ar.
C)   He.
D)   Na.
E)   Hg.F) D) and E)
G) C) and E)

Question 9

Magnesium metal reacts with hydrochloric acid to form aqueous magnesium chloride and hydrogen gas. An excess of magnesium is reacted with 20.0 mL of 3.00 M hydrochloric acid, and all of the hydrogen is collected in a balloon at 25°C and 1.00 atm. What is the expected volume of the balloon?

Accepted Answer

A)   0.734 L
B)   1.47 L
C)   0.672 L
D)   22.4 L
E)   1.34 LF) A) and B)
G) A) and C)

Question 10

At 200 K, the molecules or atoms of an unknown gas, X, have an average velocity equal to that of Ar atoms at 400 K. What is X? (Assume ideal behavior.)

Accepted Answer

A)   CO
B)   F2
C)   He
D)   HF
E)   HBrF) B) and C)
G) None of the above

Question 11

Near sea level, the atmosphere is composed of 78% nitrogen and 20% oxygen. Other trace gases make up the remaining 2%. At room temperature,

Accepted Answer

A)   all the gas molecules move at the same speed.
B)   the nitrogen gas molecules, on average, move faster than the oxygen molecules.
C)   the nitrogen gas molecules, on average, move slower than the oxygen molecules.
D)   some nitrogen gas molecules could move faster than some of the oxygen gas molecules.
E)   some nitrogen gas molecules could move slower than some of the oxygen molecules.F)   B  and  D G)   C and  DH)   B, D , and  E I) G) and H)
J) A) and D)

Question 12

Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N2 gas, and flask C contains O2 gas. Which contains the lowest density?

Accepted Answer

A)   flask A
B)   flask B
C)   flask C
D)   All are the same.
E)   Two of the flasks contain gases at the same density.F) C) and D)
G) A) and B)

Question 13

Calculate the density of nitrogen at STP.

Accepted Answer

A)   1.25 g/L
B)   0.625 g/L
C)   0.312 g/L
D)   1.60 g/L
E)   0.800 g/LF) A) and E)
G) A) and C)

Question 14

Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and
1 atm pressure.
-Which gas has the highest density?

Accepted Answer

A)   NH3
B)   CH4
C)   Cl2
D)   He
E)   All the gases have the same density.F) B) and C)
G) A) and E)

Question 15

The molar mass of gas Y is

Accepted Answer

A)   89.0 g/mol.
B)   56.0 g/mol.
C)   157 g/mol.
D)  140. g/mol.
E)   125 g/mol.F) C) and D)
G) A) and C)

Question 16

Equimolar amounts of the gases N2 and H2 are mixed in a closed container fitted with a piston (allowing the volume of the container to change, thus keeping the pressure constant) . Calculate the ratio of the final volume of the container to the initial volume of the container when the reaction N2 + 3H2  2NH3 goes to completion.

Accepted Answer

A)   1
B)   2/3
C)   3/2
D)   1/3
E)   none of theseF) A) and C)
G) A) and D)

Question 17

Consider two samples of gas at the same volume and temperature that each contains 1.0 mol of gas. Sample A contains H2 and sample B contains an unknown gas. The ratio of the impacts per second of gas A with the walls of the container to the impacts per second of gas B with the walls of the container is 4. Identify gas B.

Accepted Answer

A)   Ar
B)   CO2
C)   He
D)   Ne
E)   O2F) None of the above
G) A) and E)

Question 18

Which gas, He or H2O vapor, has the lower value of a in the van der Waals equation?

Accepted Answer

A)   H2O
B)   He
C)   The two gases have the same value of a.
D)   It depends on the conditions of pressure and temperature.E) A) and B)
F) A) and C)

Question 19

Consider two samples of helium in separate containers of the same volume. Sample 1 has an absolute temperature four times that of Sample 2. Both samples are at the same pressure. Calculate the ratio n1/n2.

Accepted Answer

A)   2:1
B)   1:1
C)   1:2
D)   4:1
E)   1:4F) None of the above
G) B) and D)

Question 20

Consider two samples of helium in separate containers of the same volume. Sample 1 has an absolute temperature four times that of Sample 2. Both samples are at the same pressure. Calculate the ratio Z1/Z2.

Accepted Answer

A)   4:1
B)   2:1
C)   1:2
D)   1:4
E)   1:1F) None of the above
G) B) and D)

Exam 5: Gases

At 200 K, the molecules or atoms of an unknown gas, X, have an average velocity equal to that of Ar atoms at 400 K. What is X? (Assume ideal behavior.)

Correct Answer
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Calculate the density of nitrogen at STP.

Correct Answer
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Consider two samples of helium in separate containers of the same volume. Sample 1 has an absolute temperature four times that of Sample 2. Both samples are at the same pressure. Calculate the ratio Z₁/Z₂.

Correct Answer
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Correct Answer
verified

Consider two samples of helium in separate containers of the same volume. Sample 1 has an absolute temperature four times that of Sample 2. Both samples are at the same pressure. Calculate the ratio n₁/n₂.

Correct Answer
verified

Correct Answer
verified

Body temperature is about 308 K. On a cold day, what volume of air at 273 K must a person with a lung capacity of 2.00 L breathe in to fill the lungs?

Correct Answer
verified

Consider three 1.0-L flasks at STP. Flask A contains Ar gas, flask B contains Kr gas, and flask C contains H₂gas. In which flask do the gas particles have the highest average velocity?

Correct Answer
verified

What volume of carbon dioxide measured at STP will be formed by the reaction of 1.30 mol of oxygen with 9.00  10^-¹ mol of ethyl alcohol (CH₃CH₂OH) ?

Correct Answer
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Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N₂ gas, and flask C contains O₂gas. In which flask do the molecules have the greatest kinetic energy?

Correct Answer
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A 259.6-L cylinder contains 63.5% He(g) and 36.5% Kr(g) by mass at 22.0°C and 1.25 atm total pressure. What is the mass of He in this container?

Correct Answer
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The molar mass of gas Y is

Correct Answer
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Near sea level, the atmosphere is composed of 78% nitrogen and 20% oxygen. Other trace gases make up the remaining 2%. At room temperature,

Correct Answer
verified

Which gas, He or H₂O vapor, has the lower value of a in the van der Waals equation?

Correct Answer
verified

A mixture of KCl and KClO₃ weighing 1.80 g was heated; the dry O₂ generated occupied 1.40  10² mL at STP. What percent of the original mixture was KClO₃? KClO₃ decomposes as follows: 2KClO₃(s)  2KCl(s) + 3O₂(g)

Correct Answer
verified

Correct Answer
verified

At 1000°C and 10. torr, the density of a certain element in the gaseous state is 2.9  10^-³ g/L. The element is

Correct Answer
verified

Magnesium metal reacts with hydrochloric acid to form aqueous magnesium chloride and hydrogen gas. An excess of magnesium is reacted with 20.0 mL of 3.00 M hydrochloric acid, and all of the hydrogen is collected in a balloon at 25°C and 1.00 atm. What is the expected volume of the balloon?

Correct Answer
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Four identical 1.0-L flasks contain the gases He, Cl₂, CH₄, and NH₃, each at 0°C and 1 atm pressure. -Which gas has the highest density?

Correct Answer
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Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N₂ gas, and flask C contains O₂gas. Which contains the lowest density?

Correct Answer
verified

Exam 5: Gases

At 200 K, the molecules or atoms of an unknown gas, X, have an average velocity equal to that of Ar atoms at 400 K. What is X? (Assume ideal behavior.)

Correct AnswerverifiedShow Answer

Calculate the density of nitrogen at STP.

Correct AnswerverifiedShow Answer

Consider two samples of helium in separate containers of the same volume. Sample 1 has an absolute temperature four times that of Sample 2. Both samples are at the same pressure. Calculate the ratio Z1/Z2.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Consider two samples of helium in separate containers of the same volume. Sample 1 has an absolute temperature four times that of Sample 2. Both samples are at the same pressure. Calculate the ratio n1/n2.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Body temperature is about 308 K. On a cold day, what volume of air at 273 K must a person with a lung capacity of 2.00 L breathe in to fill the lungs?

Correct AnswerverifiedShow Answer

Consider three 1.0-L flasks at STP. Flask A contains Ar gas, flask B contains Kr gas, and flask C contains H2 gas. In which flask do the gas particles have the highest average velocity?

Correct AnswerverifiedShow Answer

What volume of carbon dioxide measured at STP will be formed by the reaction of 1.30 mol of oxygen with 9.00  10-1 mol of ethyl alcohol (CH3CH2OH) ?

Correct AnswerverifiedShow Answer

Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N2 gas, and flask C contains O2 gas. In which flask do the molecules have the greatest kinetic energy?

Correct AnswerverifiedShow Answer

A 259.6-L cylinder contains 63.5% He(g) and 36.5% Kr(g) by mass at 22.0°C and 1.25 atm total pressure. What is the mass of He in this container?

Correct AnswerverifiedShow Answer

The molar mass of gas Y is

Correct AnswerverifiedShow Answer

Near sea level, the atmosphere is composed of 78% nitrogen and 20% oxygen. Other trace gases make up the remaining 2%. At room temperature,

Correct AnswerverifiedShow Answer

Which gas, He or H2O vapor, has the lower value of a in the van der Waals equation?

Correct AnswerverifiedShow Answer

A mixture of KCl and KClO3 weighing 1.80 g was heated; the dry O2 generated occupied 1.40  102 mL at STP. What percent of the original mixture was KClO3? KClO3 decomposes as follows: 2KClO3(s)  2KCl(s) + 3O2(g)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

At 1000°C and 10. torr, the density of a certain element in the gaseous state is 2.9  10-3 g/L. The element is

Correct AnswerverifiedShow Answer

Magnesium metal reacts with hydrochloric acid to form aqueous magnesium chloride and hydrogen gas. An excess of magnesium is reacted with 20.0 mL of 3.00 M hydrochloric acid, and all of the hydrogen is collected in a balloon at 25°C and 1.00 atm. What is the expected volume of the balloon?

Correct AnswerverifiedShow Answer

Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and 1 atm pressure. -Which gas has the highest density?

Correct AnswerverifiedShow Answer

Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N2 gas, and flask C contains O2 gas. Which contains the lowest density?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Consider two samples of helium in separate containers of the same volume. Sample 1 has an absolute temperature four times that of Sample 2. Both samples are at the same pressure. Calculate the ratio Z₁/Z₂.

Correct Answer
verified

Correct Answer
verified

Consider two samples of helium in separate containers of the same volume. Sample 1 has an absolute temperature four times that of Sample 2. Both samples are at the same pressure. Calculate the ratio n₁/n₂.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Consider three 1.0-L flasks at STP. Flask A contains Ar gas, flask B contains Kr gas, and flask C contains H₂gas. In which flask do the gas particles have the highest average velocity?

Correct Answer
verified

What volume of carbon dioxide measured at STP will be formed by the reaction of 1.30 mol of oxygen with 9.00  10^-¹ mol of ethyl alcohol (CH₃CH₂OH) ?

Correct Answer
verified

Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N₂ gas, and flask C contains O₂gas. In which flask do the molecules have the greatest kinetic energy?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Which gas, He or H₂O vapor, has the lower value of a in the van der Waals equation?

Correct Answer
verified

A mixture of KCl and KClO₃ weighing 1.80 g was heated; the dry O₂ generated occupied 1.40  10² mL at STP. What percent of the original mixture was KClO₃? KClO₃ decomposes as follows: 2KClO₃(s)  2KCl(s) + 3O₂(g)

Correct Answer
verified

Correct Answer
verified

At 1000°C and 10. torr, the density of a certain element in the gaseous state is 2.9  10^-³ g/L. The element is

Correct Answer
verified

Correct Answer
verified

Four identical 1.0-L flasks contain the gases He, Cl₂, CH₄, and NH₃, each at 0°C and 1 atm pressure. -Which gas has the highest density?

Correct Answer
verified

Consider three 1-L flasks at the same temperature and pressure. Flask A contains CO gas, flask B contains N₂ gas, and flask C contains O₂gas. Which contains the lowest density?

Correct Answer
verified