Question 1

For an ideal monatomic gas,

Accepted Answer

For an ideal monatomic gas, the heat capacity at constant pressure (C_p) is greater than the heat capacity at constant volume (C_v) because C_p = C_v + R, where R is the ideal gas constant.

Question 2

FIGURE 18-1 -An ideal monatomic gas undergoes the reversible expansion shown in the Figure 18-1, where V₂ = 5V₁ and P₂ = 3P₁. How much heat is gained by the gas in this process, in terms of the initial pressure and volume?

Accepted Answer

The answer of FIGURE 18-1 
-An ideal monatomic gas undergoes...

Question 3

A monatomic ideal gas is compressed isothermically to one-third of its initial volume. The resulting pressure will be

Accepted Answer

For an isothermal process involving an ideal gas, the pressure and volume are inversely proportional (Boyle's Law: PV = constant). If the volume is reduced to one-third, the pressure will increase by a factor of three.

Question 4

The molar specific heat is the amount of heat required to raise the temperature of what amount of matter by one unit of temperature?

Accepted Answer

Molar specific heat is defined as the amount of heat required to raise the temperature of one mole of a substance by one degree.

Question 5

FIGURE 18-1 -An ideal monatomic gas undergoes the reversible expansion shown in Figure 18-1, where V₂ = 5V₁ and P₂ = 3P₁. What is the change in internal energy of the gas in this process, in terms of the initial pressure and volume?

Accepted Answer

The answer of FIGURE 18-1 
-An ideal monatomic gas undergoes...

Question 6

When objects at different temperatures are brought into thermal contact with one another, the resulting spontaneous flow of heat proceeds from the object with the higher

Accepted Answer

Heat always flows from higher temperature to lower temperature.

Question 7

In a given reversible process, the temperature of an ideal gas is kept constant as the gas is compressed to a smaller volume. Select the true statement from among the following:

Accepted Answer

Since the temperature of the gas is kept constant and the gas is being compressed, its volume and pressure will both decrease. According to the first law of thermodynamics, the change in internal energy of a system is equal to the heat added to the system minus the work done by the system. Since the internal energy of an ideal gas is a function of temperature only, and the temperature is constant, the change in internal energy must be zero. Therefore, the work done by the system in compressing the gas must be exactly balanced by the heat released from the gas to its surroundings. Therefore, the correct statement is that the gas must release heat to its surroundings.

Question 8

When a gas expands adiabatically,

Accepted Answer

Adiabatic expansion means that there is no heat flow into or out of the system. Therefore, the first law of thermodynamics reduces to ΔU = Q - W, where Q = 0. Since W is negative (work is done by the gas), ΔU must also be negative. This means that the internal energy of the gas decreases.

Question 9

From the following statements regarding the ratio of the molar specific heat at constant pressure to the molar specific heat at constant volume, C_p/C_v, the only correct one for an ideal monatomic gas is

Accepted Answer

The answer of From the following statements regarding the ratio...

Question 10

An ideal monatomic gas undergoes a reversible expansion to 1.5 times its original volume. In which of these processes does the gas perform the most work?

Accepted Answer

The answer of An ideal monatomic gas undergoes a reversible...

Question 11

A monatomic ideal gas is compressed isobarically to one-third of its initial volume. The resulting pressure will be

Accepted Answer

In an isobaric process, the pressure remains constant. Therefore, the resulting pressure will be equal to the initial value.

Question 12

An ideal monatomic gas undergoes a reversible expansion to 1.5 times its original volume. In which of these processes does the gas have the largest loss of internal energy?

Accepted Answer

In an adiabatic process, there is no exchange of heat between the system and the surroundings. Therefore, the internal energy of the gas can only change due to work done on or by the gas. Since the gas undergoes a reversible expansion, it must do work on the surroundings, leading to a decrease in internal energy. In contrast, in processes where pressure or temperature are held constant, the gas can exchange heat with the surroundings, leading to potential changes in internal energy that cannot be solely attributed to work. Thus, the adiabatic process would result in the largest loss of internal energy.

Question 13

Two identical samples of a monatomic gas are initially at pressure P and occupy volume V. You perform two experiments which will both lead to the gas samples being compressed to final volumes one-third as large as their initial volumes. In one of the experiments you make the gas undergo an isothermal compression. In the second you make the gas undergo an adiabatic compression. It is correct to say that:

Accepted Answer

During an isothermal compression, the temperature remains constant, so the ideal gas law can be used to find that the pressure has to increase to maintain the constant temperature. However, in an adiabatic compression, no heat is exchanged with the system's surroundings. Therefore, the energy must be conserved. During an adiabatic compression, the internal energy must increase, and thus the pressure must increase to maintain the constant temperature. Therefore, the adiabatic compression will lead to a higher final pressure than the isothermal compression.

Question 14

What is meant by "the heat death of the universe"?

Accepted Answer

The heat death of the universe is the theoretical scenario in which the universe reaches a state of maximum entropy in which all matter is evenly distributed and there are no more temperature gradients or energy sources to power any kind of work or force. This means that the universe would eventually become cold, dark, and unable to sustain life or any kind of activity. This is due to the second law of thermodynamics, which states that over time, any isolated system will tend to disorder and entropy.

Question 15

A monatomic ideal gas is compressed adiabatically to one-third of its initial volume. The resulting pressure will be

Accepted Answer

According to the adiabatic compression process, PV^(gamma)=constant, where P is pressure, V is volume, and gamma is the ratio of specific heats (Cp/Cv) for a monatomic ideal gas. As the gas is compressed to one-third of its initial volume, the final volume will be (1/3)V, and thus the final pressure will be P*(V/3)^gamma. Since gamma for a monatomic ideal gas is 5/3, we can simplify this expression to P*(1/3)^(5/3) = P*(1/27). Therefore, the final pressure will be 27 times the initial pressure, which is more than three times as large as the initial value. The correct choice is therefore C.

Question 16

For water at 2°C,

Accepted Answer

At 2°C, water exists in its solid form (ice), and the density of ice is less than the density of liquid water at the same temperature. Therefore, the specific volume (v) of ice is greater than the specific volume of water. The specific heats of both ice and water at constant pressure (CP) and constant volume (CV) are different, but it is not specified which specific heat values are being referred to in the equation. Hence, we cannot make comparisons between CP and CV in this case. Therefore, based on the given information, C_p < C_v.

Question 17

An ideal monatomic gas undergoes a reversible expansion to 1.5 times its original volume. In which of these processes does the gas perform the least amount of work?

Accepted Answer

In an adiabatic process, there is no heat exchange with the surroundings, and the work done is minimized compared to other processes because the internal energy change is solely due to work done on or by the system.

Question 18

If a system undergoes a reversible process,

Accepted Answer

A reversible process is one that can be reversed without causing any net change to the system or surroundings. Therefore, if a system undergoes a reversible process, it must be possible to restore both the system and the surroundings to their original states. This is because the process does not result in any irreversible changes.

Question 19

An ideal monatomic gas undergoes an isothermal expansion. It is correct to affirm that its entropy

Accepted Answer

During an isothermal expansion, the temperature remains constant, which means that the internal energy of the gas remains the same. As the gas expands, the volume increases, which means that the number of microstates available to the system also increases. As a result, the entropy of the gas increases. Therefore, the correct option is C) increases.

Question 20

A certain gas is compressed adiabatically. The amount of work done on the gas is 800 J. What is the change in the internal energy of the gas?

Accepted Answer

In an adiabatic process, there is no heat exchange with the surroundings (Q = 0). According to the first law of thermodynamics, ΔU = Q - W. Since Q = 0, ΔU = -W. Therefore, the change in internal energy is equal to the work done on the gas, which is 800 J.

Quiz 18: The Laws of Thermodynamics