Question 1

The mass of 1.12 L of gas Y is found to be 6.23

Accepted Answer

A)   0.180 g/L.
B)   0.200 g/L.
C)   10.6 g/L.
D)   15.6 g/L.
E)   5.56 g/L.

Question 2

A 275.0-mL sample of O2 is collected over water at 60.0°C. The total pressure is 755 torr. What is the volume of the O2 at the STP? (The vapor pressure of water at 60°C is 149 torr) .

Accepted Answer

A)   244.0 mL
B)   224.0 mL
C)   180.0 mL
D)   333.0 mL
E)   none of these

Question 3

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% E

Question 4

Calculate the mean free path in a sample of oxygen gas (M = 3.20 × 10-2 kg/mol)  at 35°C and 1.7 atm. Assume that the diameter of an O2 molecule is 300 pm.

Accepted Answer

A)   0.6 × 10-7 m
B)   ​0.2 × 10-7 m
C)   1.3 × 10-7 m
D)   2.5 × 10-7 m
E)   3.3 × 10-7 m A

Question 5

The root-mean-square velocity of N2 gas at 35°C is

Accepted Answer

A)   52.0 m/s.
B)   177 m/s.
C)   5.58 m/s
D)   524 m/s.
E)   16.6 m/s

Question 6

Which gas, Kr or CO2 , has the lower value of b in the van der Waals equation?

Accepted Answer

A)   The two gases have the same value of
B)   It depends on the conditions of pressure and temperature.
C)   CO2
D)   Kr

Question 7

Calculate the following ratios for a gas at Kelvin temperatures T1 and T2 where T2 = 2T1.
-Mean free path at T1 : Mean free path at T2

Accepted Answer

A)   0.50
B)   1.4
C)   2.0
D)   0.71
E)   1.0

Question 8

Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and 1 atm pressure.
-For which gas do the molecules have the smallest average kinetic energy?

Accepted Answer

A)   He
B)   CH4
C)   NH3
D)   Cl2
E)   The molecules of all the gases have the same average kinetic energy.

Question 9

Consider two 1.0-L containers, one containing He(g)  at 2.50 atm and 24°C and the other containing Ar(g)  at 5.00 atm and 48°C.
-Calculate the ratio of average velocities (He:Ar) .

Accepted Answer

A)   0.108
B)   4.98
C)   0.200
D)   9.22
E)   none of these

Question 10

Which of the following relationships is not true?

Accepted Answer

A)   PV = constant when temperature and moles of gas are held constant.
B)   V/T = constant when pressure and moles of gas are held constant.
C)   nT = constant when pressure and volume are held constant.
D)   P/n = constant when volume and temperature are held constant.
E)   All of these are true.

Question 11

A 3.82-g sample of lead(II)  nitrate, Pb(NO3) 2, molar mass = 331 g/mol, is heated in an evacuated cylinder with a volume of 1.70 L. The salt decomposes when heated, according to the equation
2Pb(NO3) 2(s)  → 2PbO(s)  + 4NO2(g)  + O2(g) 
Assuming complete decomposition, what is the pressure in the cylinder after decomposition and cooling to a temperature of 290. K? Assume the PbO(s)  takes up negligible volume.

Accepted Answer

A)   0.565 atm
B)   0.162 atm
C)   0.784 atm
D)   0.808 atm
E)   0.404 atm

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.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.

Question 13

A certain element (Z) reacts to form three gaseous compounds. Consider the following data (pressure = 1.0 atm).  
Determine the identity of element Z.

Accepted Answer

The answer of A certain element (Z) reacts to form...

Question 14

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)   1:4

Question 15

Which statement about kinetic energy (K.E.)  is true?

Accepted Answer

A)   The K.E. of a body will double if its velocity doubles.
B)   As the velocity of a body increases, its K.E. decreases.
C)   The K.E. of a body is independent of its mass.
D)   All objects moving with the same velocity have the same K.E.
E)   None of these statements is true.

Question 16

Calculate the temperature at which the average kinetic energy of O2 gas is twice that of He gas at 10.0°C.

Accepted Answer

A)   293°C
B)   20.0°C
C)   160.0°C
D)   2.50°C
E)   10.0°C

Question 17

Air has an average molar mass of 29.0 g/mol. The density of air at 1.00 atm and 30°C is

Accepted Answer

A)   40.0 g/mL.
B)   1.17 g/L.
C)   1.29 g/L.
D)   12 g/L.
E)   29.0 g/L.

Question 18

Calculate the following ratios for a gas at Kelvin temperatures T1 and T2 where T2 = 2T1.Average kinetic energy at T1 : Average kinetic energy at T2

Accepted Answer

A)   2.0
B)   0.50
C)   0.71
D)   1.0
E)   1.4

Question 19

A sample of helium gas has been contaminated with argon gas. At 1 atm and 25°C, the density of the mixture is 0.200 g/L. What is the volume percent argon in the sample?

Accepted Answer

The answer of A sample of helium gas has been...

Question 20

Air is 79% N2 and 21% O2 by volume. Calculate the density of air at 1.0 atm, 25°C.

Accepted Answer

A)   1.18 g/L
B)   2.46 g/L
C)   0.590 g/L
D)   14.1 g/L
E)   none of these A

Exam 5: Gases

The mass of 1.12 L of gas Y is found to be 6.23

Correct Answer
verified

A 275.0-mL sample of O₂ is collected over water at 60.0°C. The total pressure is 755 torr. What is the volume of the O₂ at the STP? (The vapor pressure of water at 60°C is 149 torr) .

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
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E

Calculate the mean free path in a sample of oxygen gas (M = 3.20 × 10^-2 kg/mol) at 35°C and 1.7 atm. Assume that the diameter of an O₂ molecule is 300 pm.

Correct Answer
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A

The root-mean-square velocity of N₂ gas at 35°C is

Correct Answer
verified

Which gas, Kr or CO₂ , has the lower value of b in the van der Waals equation?

Correct Answer
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Calculate the following ratios for a gas at Kelvin temperatures T₁ and T₂ where T₂ = 2T₁. -Mean free path at T₁ : Mean free path at T₂

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. -For which gas do the molecules have the smallest average kinetic energy?

Correct Answer
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Consider two 1.0-L containers, one containing He(g) at 2.50 atm and 24°C and the other containing Ar(g) at 5.00 atm and 48°C. -Calculate the ratio of average velocities (He:Ar) .

Correct Answer
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Which of the following relationships is not true?

Correct Answer
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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 O₂ gas.In which flask do the molecules have the greatest kinetic energy?

Correct Answer
verified

A certain element (Z) reacts to form three gaseous compounds. Consider the following data (pressure = 1.0 atm). Determine the identity of element Z.

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
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Which statement about kinetic energy (K.E.) is true?

Correct Answer
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Calculate the temperature at which the average kinetic energy of O₂ gas is twice that of He gas at 10.0°C.

Correct Answer
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Air has an average molar mass of 29.0 g/mol. The density of air at 1.00 atm and 30°C is

Correct Answer
verified

Calculate the following ratios for a gas at Kelvin temperatures T₁ and T₂ where T₂ = 2T₁.Average kinetic energy at T₁ : Average kinetic energy at T₂

Correct Answer
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A sample of helium gas has been contaminated with argon gas. At 1 atm and 25°C, the density of the mixture is 0.200 g/L. What is the volume percent argon in the sample?

Correct Answer
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Air is 79% N₂ and 21% O₂ by volume. Calculate the density of air at 1.0 atm, 25°C.

Correct Answer
verified
A

Exam 5: Gases

The mass of 1.12 L of gas Y is found to be 6.23

Correct AnswerverifiedShow Answer

A 275.0-mL sample of O2 is collected over water at 60.0°C. The total pressure is 755 torr. What is the volume of the O2 at the STP? (The vapor pressure of water at 60°C is 149 torr) .

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 AnswerverifiedE

Calculate the mean free path in a sample of oxygen gas (M = 3.20 × 10-2 kg/mol) at 35°C and 1.7 atm. Assume that the diameter of an O2 molecule is 300 pm.

Correct AnswerverifiedA

The root-mean-square velocity of N2 gas at 35°C is

Correct AnswerverifiedShow Answer

Which gas, Kr or CO2 , has the lower value of b in the van der Waals equation?

Correct AnswerverifiedShow Answer

Calculate the following ratios for a gas at Kelvin temperatures T1 and T2 where T2 = 2T1. -Mean free path at T1 : Mean free path at T2

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. -For which gas do the molecules have the smallest average kinetic energy?

Correct AnswerverifiedShow Answer

Consider two 1.0-L containers, one containing He(g) at 2.50 atm and 24°C and the other containing Ar(g) at 5.00 atm and 48°C. -Calculate the ratio of average velocities (He:Ar) .

Correct AnswerverifiedShow Answer

Which of the following relationships is not true?

Correct AnswerverifiedShow Answer

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 certain element (Z) reacts to form three gaseous compounds. Consider the following data (pressure = 1.0 atm). Determine the identity of element Z.

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

Which statement about kinetic energy (K.E.) is true?

Correct AnswerverifiedShow Answer

Calculate the temperature at which the average kinetic energy of O2 gas is twice that of He gas at 10.0°C.

Correct AnswerverifiedShow Answer

Air has an average molar mass of 29.0 g/mol. The density of air at 1.00 atm and 30°C is

Correct AnswerverifiedShow Answer

Calculate the following ratios for a gas at Kelvin temperatures T1 and T2 where T2 = 2T1.Average kinetic energy at T1 : Average kinetic energy at T2

Correct AnswerverifiedShow Answer

A sample of helium gas has been contaminated with argon gas. At 1 atm and 25°C, the density of the mixture is 0.200 g/L. What is the volume percent argon in the sample?

Correct AnswerverifiedShow Answer

Air is 79% N2 and 21% O2 by volume. Calculate the density of air at 1.0 atm, 25°C.

Correct AnswerverifiedA

Correct Answer
verified

A 275.0-mL sample of O₂ is collected over water at 60.0°C. The total pressure is 755 torr. What is the volume of the O₂ at the STP? (The vapor pressure of water at 60°C is 149 torr) .

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
E

Calculate the mean free path in a sample of oxygen gas (M = 3.20 × 10^-2 kg/mol) at 35°C and 1.7 atm. Assume that the diameter of an O₂ molecule is 300 pm.

Correct Answer
verified
A

The root-mean-square velocity of N₂ gas at 35°C is

Correct Answer
verified

Which gas, Kr or CO₂ , has the lower value of b in the van der Waals equation?

Correct Answer
verified

Calculate the following ratios for a gas at Kelvin temperatures T₁ and T₂ where T₂ = 2T₁. -Mean free path at T₁ : Mean free path at T₂

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. -For which gas do the molecules have the smallest average kinetic energy?

Correct Answer
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Correct Answer
verified

Correct Answer
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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 O₂ gas.In which flask do the molecules have the greatest kinetic energy?

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

Calculate the temperature at which the average kinetic energy of O₂ gas is twice that of He gas at 10.0°C.

Correct Answer
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Correct Answer
verified

Calculate the following ratios for a gas at Kelvin temperatures T₁ and T₂ where T₂ = 2T₁.Average kinetic energy at T₁ : Average kinetic energy at T₂

Correct Answer
verified

Correct Answer
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Air is 79% N₂ and 21% O₂ by volume. Calculate the density of air at 1.0 atm, 25°C.

Correct Answer
verified
A