Question 1

A 2.0-m3 weather balloon is loosely filled with helium at 1 atm (76 cm Hg)and at 27°C.At an elevation of 20,000 ft, the atmospheric pressure is down to 38 cm Hg and the helium has expanded, being under no constraint from the confining bag.If the temperature at this elevation is -48°C, the gas volume is:

Accepted Answer

A) 0.75 m3  
B) 1.3 m3 
C) 3.0 m3 
D) 4.0 m3 
E) 5.3 m3

Question 2

A diatomic gas can have internal energy consisting of:

Accepted Answer

A) translational motion only 
B) rotational motion only 
C) oscillatory motion only 
D) both translational and rotational motion 
E) translational, rotational, and oscillatory motion, depending on temperature

Question 3

The speeds of 25 molecules are distributed as follows: 5 in the range from 2 to 3 m/s, 10 in the range from 3 to 4 m/s, 5 in the range from 4 to 5 m/s, 3 in the range from 5 to 6 m/s, 1 in the range from 6 to 7 m/s, and 1 in the range from 7 to 8 m/s.Their average speed is about:

Accepted Answer

A) 2 m/s 
B) 3 m/s 
C) 4 m/s 
D) 5 m/s 
E) 6 m/s

Question 4

Both the pressure and volume of an ideal gas of diatomic molecules are doubled.The ratio of the new internal energy to the old both measured relative to the internal energy at 0 K is:

Accepted Answer

A) 1/4 
B) 1/2 
C) 1 
D) 2 
E) 4

Question 5

An air bubble doubles in volume as it rises from the bottom of a lake (1000 kg/m3).Ignoring any temperature changes, the depth of the lake is:

Accepted Answer

A) 21 m 
B) 0.76 m 
C) 4.9 m 
D) 10 m 
E) 0.99 m

Question 6

The temperature of n moles of an ideal monatomic gas is increased by $\Delta$T at constant pressure.The energy Q absorbed as heat, change $\Delta$Eint in internal energy, and work W done by the environment are given by:

Accepted Answer

A) Q = (5/2)nR$\Delta$T, $\Delta$Eint = 0, W = -nR$\Delta$T 
B) Q = (3/2)nR$\Delta$T, $\Delta$Eint = (5/2)nR$\Delta$T, W = -(3/2)nR$\Delta$T 
C) Q = (5/2)nR$\Delta$T, $\Delta$Eint = (5/2)nR$\Delta$T, W = 0 
D) Q = (3/2)nR$\Delta$T, $\Delta$Eint = 0, W = -nR$\Delta$T 
E) Q = (5/2)nR$\Delta$T, $\Delta$Eint = (3/2)nR$\Delta$T, W = -nR$\Delta$T

Question 7

The number of degrees of freedom of a triatomic molecule is:

Accepted Answer

A) 1 
B) 3 
C) 6 
D) 8 
E) 9

Question 8

Ideal monatomic gas A is composed of molecules with mass m while ideal monatomic gas B is composed of molecules with mass 4m.The average molecular speeds are the same if the ratio of the temperatures TA/TB is:

Accepted Answer

A) 1/4 
B) 1/2 
C) 1 
D) 2 
E) 4

Question 9

According to the kinetic theory of gases, the pressure of a gas is due to:

Accepted Answer

A) change of kinetic energy of molecules as they strike the wall 
B) change of momentum of molecules as they strike the wall 
C) average kinetic energy of the molecules 
D) force of repulsion between the molecules 
E) rms speed of the molecules

Question 10

Use R = 8.2 *10-5 m3 . atm/mol .K and NA = 6.02 * 1023 mol-1.The approximate number of air molecules in a 1 m3 volume at room temperature (300 K)and atmospheric pressure is:

Accepted Answer

A) 41 
B) 450 
C) 2.4 *1025 
D) 2.7*1026 
E) 5.4 * 1026

Question 11

The ratio of the specific heat of a gas at constant volume to its specific heat at constant pressure is:

Accepted Answer

A) 1 
B) less than 1 
C) more than 1 
D) has units of pressure/volume 
E) has units of volume/pressure

Question 12

A system consists of N gas molecules, each with mass m.Their rms speed is vrms.Their total translational kinetic energy is:

Accepted Answer

A) (1/2)m(Nvrms)2 
B) (1/2)N(mvrms)2 
C) (1/2)mv2rms 
D) (1/2)Nmv2rms 
E) N[(1/2)mvrms]2

Question 13

An ideal gas is at a temperature of 320 K.What is the average translational kinetic energy of one of its molecules?

Accepted Answer

A) 9.2 x 10-24 J 
B) 1.4 x 10-23 J 
C) 2.1 x 10-23 J 
D) cannot tell without knowing the molar mass 
E) cannot tell without knowing whether the gas is monatomic or diatomic

Question 14

The difference between the molar specific heat at constant pressure and the molar specific heat at constant volume for an ideal gas is:

Accepted Answer

A) the Boltzmann constant k 
B) the universal gas constant R 
C) the Avogadro number NA 
D) kT 
E) RT

Exam 19: The Kinetic Theory of Gases

A diatomic gas can have internal energy consisting of:

The speeds of 25 molecules are distributed as follows: 5 in the range from 2 to 3 m/s, 10 in the range from 3 to 4 m/s, 5 in the range from 4 to 5 m/s, 3 in the range from 5 to 6 m/s, 1 in the range from 6 to 7 m/s, and 1 in the range from 7 to 8 m/s.Their average speed is about:

Both the pressure and volume of an ideal gas of diatomic molecules are doubled.The ratio of the new internal energy to the old both measured relative to the internal energy at 0 K is:

An air bubble doubles in volume as it rises from the bottom of a lake (1000 kg/m³) .Ignoring any temperature changes, the depth of the lake is:

The temperature of n moles of an ideal monatomic gas is increased by $\Delta$ T at constant pressure.The energy Q absorbed as heat, change $\Delta$ E_int in internal energy, and work W done by the environment are given by:

The number of degrees of freedom of a triatomic molecule is:

Ideal monatomic gas A is composed of molecules with mass m while ideal monatomic gas B is composed of molecules with mass 4m.The average molecular speeds are the same if the ratio of the temperatures T_A/T_B is:

According to the kinetic theory of gases, the pressure of a gas is due to:

Use R = 8.2 10^-5 m³ . atm/mol .K and N_A = 6.02 10²³ mol^-1.The approximate number of air molecules in a 1 m³ volume at room temperature (300 K) and atmospheric pressure is:

The ratio of the specific heat of a gas at constant volume to its specific heat at constant pressure is:

A system consists of N gas molecules, each with mass m.Their rms speed is v_rms.Their total translational kinetic energy is:

An ideal gas is at a temperature of 320 K.What is the average translational kinetic energy of one of its molecules?

The difference between the molar specific heat at constant pressure and the molar specific heat at constant volume for an ideal gas is:

Exam 19: The Kinetic Theory of Gases

A diatomic gas can have internal energy consisting of:

The speeds of 25 molecules are distributed as follows: 5 in the range from 2 to 3 m/s, 10 in the range from 3 to 4 m/s, 5 in the range from 4 to 5 m/s, 3 in the range from 5 to 6 m/s, 1 in the range from 6 to 7 m/s, and 1 in the range from 7 to 8 m/s.Their average speed is about:

Both the pressure and volume of an ideal gas of diatomic molecules are doubled.The ratio of the new internal energy to the old both measured relative to the internal energy at 0 K is:

An air bubble doubles in volume as it rises from the bottom of a lake (1000 kg/m3) .Ignoring any temperature changes, the depth of the lake is:

The temperature of n moles of an ideal monatomic gas is increased by Δ\DeltaΔ T at constant pressure.The energy Q absorbed as heat, change Δ\DeltaΔ Eint in internal energy, and work W done by the environment are given by:

The number of degrees of freedom of a triatomic molecule is:

Ideal monatomic gas A is composed of molecules with mass m while ideal monatomic gas B is composed of molecules with mass 4m.The average molecular speeds are the same if the ratio of the temperatures TA/TB is:

According to the kinetic theory of gases, the pressure of a gas is due to:

Use R = 8.2 *10-5 m3 . atm/mol .K and NA = 6.02 * 1023 mol-1.The approximate number of air molecules in a 1 m3 volume at room temperature (300 K) and atmospheric pressure is:

The ratio of the specific heat of a gas at constant volume to its specific heat at constant pressure is:

A system consists of N gas molecules, each with mass m.Their rms speed is vrms.Their total translational kinetic energy is:

An ideal gas is at a temperature of 320 K.What is the average translational kinetic energy of one of its molecules?

The difference between the molar specific heat at constant pressure and the molar specific heat at constant volume for an ideal gas is:

An air bubble doubles in volume as it rises from the bottom of a lake (1000 kg/m³) .Ignoring any temperature changes, the depth of the lake is:

The temperature of n moles of an ideal monatomic gas is increased by $\Delta$ T at constant pressure.The energy Q absorbed as heat, change $\Delta$ E_int in internal energy, and work W done by the environment are given by:

Ideal monatomic gas A is composed of molecules with mass m while ideal monatomic gas B is composed of molecules with mass 4m.The average molecular speeds are the same if the ratio of the temperatures T_A/T_B is:

Use R = 8.2 10^-5 m³ . atm/mol .K and N_A = 6.02 10²³ mol^-1.The approximate number of air molecules in a 1 m³ volume at room temperature (300 K) and atmospheric pressure is:

A system consists of N gas molecules, each with mass m.Their rms speed is v_rms.Their total translational kinetic energy is: