Question 1

If CP for an ideal gas is 35.4 J/mol⋅K, which of the following is CV for this gas?

Accepted Answer

A) 12.5 J/mol⋅K 
B) 20.8 J/mol⋅K 
C) 29.1 J/mol⋅K 
D) 27.1 J/mol⋅K 
E) 43.4 J/mol⋅K 
A) 12.5 J/mol⋅K 
B) 20.8 J/mol⋅K 
C) 29.1 J/mol⋅K 
D) 27.1 J/mol⋅K 
E) 43.4 J/mol⋅K D

Question 2

The internal energy of n moles of an ideal gas depends on

Accepted Answer

A) one state variable T. 
B) two state variables T and V. 
C) two state variables T and P. 
D) three state variables T, P and V. 
E) four variables R, T, P and V. 
A) one state variable T. 
B) two state variables T and V. 
C) two state variables T and P. 
D) three state variables T, P and V. 
E) four variables R, T, P and V. A

Question 3

If the rms speed of helium atoms is vrms,He at temperature T, what is the rms speed of CO2 at the same temperature?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)    D

Question 4

Two tanks of gas, one of hydrogen, H2, and one of helium, He, contain equal masses of gas. The gram-molecular mass of He is twice that of H2. Both tanks of gas are at the same temperature, 293 K. Which statement(s) below is(are) correct when we ignore vibrational motion?

Accepted Answer

A) The total internal energy of the hydrogen is the same as that of the helium. 
B) The total internal energy of the hydrogen is 167 times that of the helium. 
C) The total internal energy of the helium is 1.67 times that of the hydrogen. 
D) The total internal energy of the hydrogen is 3.33 times that of the helium. 
E) The total internal energy of the helium is 3.33 times that of the hydrogen. 
A) The total internal energy of the hydrogen is the same as that of the helium. 
B) The total internal energy of the hydrogen is 167 times that of the helium. 
C) The total internal energy of the helium is 1.67 times that of the hydrogen. 
D) The total internal energy of the hydrogen is 3.33 times that of the helium. 
E) The total internal energy of the helium is 3.33 times that of the hydrogen.

Question 5

During the volcanic eruption of Mt. Pelee in 1902, an incredibly hot "burning cloud" rolled down the mountain and incinerated the town of Saint-Pierre. From the damage done, the temperature in the cloud was estimated at 700°C. If the air temperature was 20°C and a mole of air is 29 grams, estimate the molecular weight of the gas in the "burning cloud" that made it heavier than the surrounding air. (As a follow-on, estimate the most probable composition of the cloud. Some typical volcanic gases are H2S, SO2, H2SO4, CO2, NO.)

Accepted Answer

96, H₂SO₄ (s

Question 6

Two tanks of gas, one of hydrogen, H2, and one of helium, He, contain equal numbers of moles of gas. The gram-molecular mass of He is twice that of H2. Both tanks of gas are at the same temperature, 293 K. Which statement(s) below is(are) correct when we ignore vibrational motion?

Accepted Answer

A) The total internal energy of the hydrogen is the same as that of the helium. 
B) The total internal energy of the hydrogen is 1.4 times that of the helium. 
C) The total internal energy of the helium is 1.4 times that of the hydrogen. 
D) The total internal energy of the hydrogen is 1.67 times that of the helium. 
E) The total internal energy of the helium is 1.67 times that of the hydrogen. 
A) The total internal energy of the hydrogen is the same as that of the helium. 
B) The total internal energy of the hydrogen is 1.4 times that of the helium. 
C) The total internal energy of the helium is 1.4 times that of the hydrogen. 
D) The total internal energy of the hydrogen is 1.67 times that of the helium. 
E) The total internal energy of the helium is 1.67 times that of the hydrogen.

Question 7

According to kinetic theory, a typical gas molecule in thermal equilibrium at room temperature has a kinetic energy K = 6.00 × 10−21 J, regardless of mass. Estimate the speed at room temperature of a hydrogen molecule H2 (m = 3.34 × 10−27 kg) and a xenon atom (m = 2.00 × 10−25 kg). [kB = 1.38 × 10−23 J/K]

Accepted Answer

Question 8

One mole of hydrogen, one mole of nitrogen and one mole of oxygen are held in a 22.4 × 103 cm3 enclosed vessel at 20°C. The pressure in the vessel, in N/m2, is

Accepted Answer

A) 109. 
B) 304. 
C) 326. 
D) 1.09 × 105. 
E) 3.26 × 105. 
A) 109. 
B) 304. 
C) 326. 
D) 1.09 × 105. 
E) 3.26 × 105.

Question 9

During an adiabatic compression, a volume of air decreases to 1/4 its original size. Calculate its final pressure if its original pressure was 1 atm. (Assume the air behaves like an ideal gas with γ = 1.4.)

Accepted Answer

A) 7.0 atm 
B) 5.6 atm 
C) 3.5 atm 
D) 2.2 atm 
E) 0.14 atm 
A) 7.0 atm 
B) 5.6 atm 
C) 3.5 atm 
D) 2.2 atm 
E) 0.14 atm

Question 10

When we consider a thin horizontal layer of the atmosphere, of thickness dy, of area A, with pressure P on the bottom, with an average mass m per molecule, and nV molecules per unit volume, the magnitude of the difference of the pressure at the top and bottom of the layer is given by dP =

Accepted Answer

A) mgdy. 
B) mgnVdy. 
C) mgAdy. 
D) mgnVAdy. 
E) mgnVAPdy. 
A) mgdy. 
B) mgnVdy. 
C) mgAdy. 
D) mgnVAdy. 
E) mgnVAPdy.

Question 11

An ideal gas is allowed to expand adiabatically until its volume increases by 50%. By approximately what factor is the pressure reduced? (γ = 5/3.)

Accepted Answer

A) 1.5 
B) 2.0 
C) 2.5 
D) 3.0 
E) 3.5 
A) 1.5 
B) 2.0 
C) 2.5 
D) 3.0 
E) 3.5

Question 12

The root mean square speed of a gas molecule is greater than the average speed, because the former gives a greater weight to

Accepted Answer

A) lighter molecules. 
B) heavier molecules. 
C) lower speeds. 
D) higher speeds. 
E) more probable speeds. 
A) lighter molecules. 
B) heavier molecules. 
C) lower speeds. 
D) higher speeds. 
E) more probable speeds.

Question 13

The average molecular translational kinetic energy of a molecule in an ideal gas is

Accepted Answer

A)    kBT. 
B)    RT. 
C)    kBT. 
D)    RT. 
E)    kBT, where n = number of internal degrees of freedom. 
A)    kBT. 
B)    RT. 
C)    kBT. 
D)    RT. 
E)    kBT, where n = number of internal degrees of freedom.

Question 14

A container having a volume of 1.0 m3 holds 5.0 moles of helium gas at 50°C. If the helium behaves like an ideal gas, the total energy of the system is

Accepted Answer

A) 2.0 × 104 J. 
B) 2.5 × 104 J. 
C) 1.7 × 103 J. 
D) 1.5 × 103 J. 
E) 4.0 × 104 J. 
A) 2.0 × 104 J. 
B) 2.5 × 104 J. 
C) 1.7 × 103 J. 
D) 1.5 × 103 J. 
E) 4.0 × 104 J.

Question 15

A container having a volume of 1.0 m3 holds 5.0 moles of helium gas at 50°C. If the helium behaves like an ideal gas, the average kinetic energy per molecule is

Accepted Answer

A) 6.7 × 10−20 J. 
B) 1.0 × 10−21 J. 
C) 1.0 × 10−20 J. 
D) 6.7 × 10−21 J. 
E) 1.3 × 10−20 J. 
A) 6.7 × 10−20 J. 
B) 1.0 × 10−21 J. 
C) 1.0 × 10−20 J. 
D) 6.7 × 10−21 J. 
E) 1.3 × 10−20 J.

Question 16

The temperature of a quantity of an ideal gas is

Accepted Answer

A) one measure of its ability to transfer thermal energy to another body. 
B) proportional to the average molecular kinetic energy of the molecules. 
C) proportional to the internal energy of the gas. 
D) correctly described by all the statements above. 
E) correctly described only by (a) and (b) above. 
A) one measure of its ability to transfer thermal energy to another body. 
B) proportional to the average molecular kinetic energy of the molecules. 
C) proportional to the internal energy of the gas. 
D) correctly described by all the statements above. 
E) correctly described only by (a) and (b) above.

Question 17

A molecule in a uniform ideal gas can collide with other molecules when their centers are equal to or less than

Accepted Answer

A) one radius away from its center. 
B) one diameter away from its center. 
C) two diameters away from its center. 
D) twice the cube root of volume away from its center. 
E)    diameters away from its center. 
A) one radius away from its center. 
B) one diameter away from its center. 
C) two diameters away from its center. 
D) twice the cube root of volume away from its center. 
E)    diameters away from its center.

Question 18

A 50-gram sample of dry ice (solid CO2) is placed in a 4-liter container. The system is sealed and allowed to reach room temperature (20°C). By approximately how much does the pressure inside the container increase when the dry ice turns to gas? (Ignore the initial volume of the sample.)

Accepted Answer

the pressu

Question 19

Which statement below is NOT an assumption made in the molecular model of an ideal gas?

Accepted Answer

A) The average separation between molecules is large compared with the dimensions of the molecules. 
B) The molecules undergo inelastic collisions with one another. 
C) The forces between molecules are short range. 
D) The molecules obey Newton's laws of motion. 
E) Any molecule can move in any direction with equal probability. 
A) The average separation between molecules is large compared with the dimensions of the molecules. 
B) The molecules undergo inelastic collisions with one another. 
C) The forces between molecules are short range. 
D) The molecules obey Newton's laws of motion. 
E) Any molecule can move in any direction with equal probability.

Exam 20: Kinetic Theory of Gases

If CP for an ideal gas is 35.4 J/mol⋅K, which of the following is CV for this gas?

The internal energy of n moles of an ideal gas depends on

If the rms speed of helium atoms is vrms,He at temperature T, what is the rms speed of CO2 at the same temperature?

Two tanks of gas, one of hydrogen, H2, and one of helium, He, contain equal masses of gas. The gram-molecular mass of He is twice that of H2. Both tanks of gas are at the same temperature, 293 K. Which statement(s) below is(are) correct when we ignore vibrational motion?

Two tanks of gas, one of hydrogen, H2, and one of helium, He, contain equal numbers of moles of gas. The gram-molecular mass of He is twice that of H2. Both tanks of gas are at the same temperature, 293 K. Which statement(s) below is(are) correct when we ignore vibrational motion?

One mole of hydrogen, one mole of nitrogen and one mole of oxygen are held in a 22.4 × 103 cm3 enclosed vessel at 20°C. The pressure in the vessel, in N/m2, is

During an adiabatic compression, a volume of air decreases to 1/4 its original size. Calculate its final pressure if its original pressure was 1 atm. (Assume the air behaves like an ideal gas with γ = 1.4.)

When we consider a thin horizontal layer of the atmosphere, of thickness dy, of area A, with pressure P on the bottom, with an average mass m per molecule, and nV molecules per unit volume, the magnitude of the difference of the pressure at the top and bottom of the layer is given by dP =

An ideal gas is allowed to expand adiabatically until its volume increases by 50%. By approximately what factor is the pressure reduced? (γ = 5/3.)

The root mean square speed of a gas molecule is greater than the average speed, because the former gives a greater weight to

The average molecular translational kinetic energy of a molecule in an ideal gas is

A container having a volume of 1.0 m3 holds 5.0 moles of helium gas at 50°C. If the helium behaves like an ideal gas, the total energy of the system is

A container having a volume of 1.0 m3 holds 5.0 moles of helium gas at 50°C. If the helium behaves like an ideal gas, the average kinetic energy per molecule is

The temperature of a quantity of an ideal gas is

A molecule in a uniform ideal gas can collide with other molecules when their centers are equal to or less than

A 50-gram sample of dry ice (solid CO2) is placed in a 4-liter container. The system is sealed and allowed to reach room temperature (20°C). By approximately how much does the pressure inside the container increase when the dry ice turns to gas? (Ignore the initial volume of the sample.)

Which statement below is NOT an assumption made in the molecular model of an ideal gas?

Getting Started

One-Dimensional Motion

Vectors

Two- and Three-Dimensional Motion

Newtons Laws of Motion

Applications of Newtons Laws of Motion

Gravity

Conservation of Energy

Energy in Nonisolated Systems

Systems of Particles and Conservation of Momentum

Collisions

Rotation I: Kinematics and Dynamics

Rotation II: a Conservation Approach

Static Equilibrium, Elasticity, and Fracture

Fluids

Oscillations

Traveling Waves

Superposition and Standing Waves

Temperature, Thermal Expansion, and Gas Laws

Heat and the First Law of Thermodynamics

Entropy and the Second Law of Thermodynamics

Electric Forces

Electric Fields

Gausss Law

Electric Potential

Capacitors and Batteries

Current and Resistance

Direct Current Dc Circuits

Magnetic Fields and Forces

Gausss Law for Magnetism and Amperes Law

Faradays Law of Induction

Inductors and Ac Circuits

Maxwells Equations and Electromagnetic Waves

Diffraction and Interference

Applications of the Wave Model

Reflection and Images Formed by Reflection

Refraction and Images Formed by Refraction

Relativity

Filters

If the rms speed of helium atoms is vrms,He at temperature T, what is the rms speed of CO₂ at the same temperature?

One mole of hydrogen, one mole of nitrogen and one mole of oxygen are held in a 22.4 × 10³ cm³ enclosed vessel at 20°C. The pressure in the vessel, in N/m², is

A container having a volume of 1.0 m³ holds 5.0 moles of helium gas at 50°C. If the helium behaves like an ideal gas, the total energy of the system is

A container having a volume of 1.0 m³ holds 5.0 moles of helium gas at 50°C. If the helium behaves like an ideal gas, the average kinetic energy per molecule is

A 50-gram sample of dry ice (solid CO₂) is placed in a 4-liter container. The system is sealed and allowed to reach room temperature (20°C). By approximately how much does the pressure inside the container increase when the dry ice turns to gas? (Ignore the initial volume of the sample.)