Question 1

As defined by Ludwig Boltzmann,the third law of thermodynamics states that

Accepted Answer

The third law of thermodynamics states that the entropy of a perfect crystal at absolute zero (0 K) is zero. This means that there is no disorder or randomness in the crystal at this temperature. Option A accurately represents this definition. The other choices are either unrelated or incorrect.

Question 2

A statement of the first law of thermodynamics is that

Accepted Answer

The first law of thermodynamics, also known as the law of conservation of energy, states that the total energy of the universe is constant. Energy can neither be created nor destroyed, but it can be converted from one form to another.

Question 3

Which of the following linear chain alcohols is likely to have the highest standard entropy in the liquid state?

Accepted Answer

Entropy generally increases with molecular complexity and size because larger molecules have more vibrational modes and thus more ways to distribute energy. Option E represents the longest linear chain alcohol, implying it has the highest standard entropy in the liquid state due to its increased molecular complexity and size.

Question 4

In which reaction is $\Delta$_rS° expected to be negative?

Accepted Answer

The answer of In which reaction is $\Delta$_rS° expected to...

Question 5

If a chemical reaction occurs in a direction that has a positive change in entropy then

Accepted Answer

A positive change in entropy indicates an increase in disorder within the system.

Question 6

Which of the following changes lead to a $\underline{\text{ decrease }}$  in entropy?

Accepted Answer

Halving the volume of a gas leads to a decrease in entropy, as the molecules are confined to a smaller space and have less disorder.

Question 7

Which of the following statements concerning entropy change is/are true? 1)For a reversible process, ) 2)For a spontaneous process, ) 3)For a reversible process,such as a phase change,$\Delta$S = q_rev/T .

Accepted Answer

1) True, because for a reversible process, the entropy change is only dependent on the heat exchanged and the temperature at which it is exchanged.
2) True, because for a spontaneous process, the entropy change of the universe always increases.
3) True, because for a reversible process, the change in entropy during a phase change can be calculated using the equation: ΔS = q/T.

Question 8

Which of the following compounds has the highest standard entropy per mole at 298 K?

Accepted Answer

The standard entropy of a gas is generally higher than that of a solid or a liquid. Among the given compounds, CO is the only gas, which means it has the highest standard entropy per mole at 298 K.

Question 9

The following processes occur spontaneously at 25 S1U1P1$\circ$S1S1P0C.Which of these processes is/are endothermic? 1)NH₄NO₃ dissolving in water (which is accompanied by a cooling of the water). 2)the expansion of a real gas into a vacuum (which is accompanied by a cooling of the gas). 3)liquid water in an ice cube tray freezing into ice after being placed in a freezer.

Accepted Answer

1) is endothermic because it is accompanied by a cooling of the water. 2) is endothermic because it is accompanied by a cooling of the gas.

Question 10

When a chemical process occurs under standard conditions,which of the following conditions always apply?
1)Gaseous species are at a pressure of 1 bar.
2)Solution concentrations species are 1 molal.
3)The temperature is 298.15 K.

Accepted Answer

The answer of When a chemical process occurs under standard...

Question 11

Which of the following statements is/are CORRECT?
1)Spontaneous changes only occur in the direction that leads to equilibrium.
2)Exothermic reactions are always spontaneous.
3)In any chemical reaction,energy must be conserved.

Accepted Answer

1) Spontaneous changes occur in the direction that leads to equilibrium or maximizes entropy. 
2) Exothermic reactions can be spontaneous, but not always. It depends on the entropy change and temperature. 
3) Energy must be conserved in any chemical reaction according to the law of conservation of energy.

Question 12

Which of the following statements concerning entropy is $\underline{\text{ not  }}$ correct?

Accepted Answer

This statement is incorrect because the spontaneous expansion of a gas is a result of an increase in entropy due to the dispersal of molecules into a larger volume, increasing the number of available microstates. Therefore, option D is the correct answer.

Question 13

For a certain reversible process q = 57.40 kJ at 36.6S1U1P1$\circ$S1S1P0C.What is $\Delta$S for the process?

Accepted Answer

The answer of For a certain reversible process q =...

Question 14

For which of the following reactions will the entropy of the system decrease?

Accepted Answer

In reaction D, two moles of gas (NO2) are converted into one mole of gas (N2O4), resulting in a decrease in the number of gas molecules and thus a decrease in entropy.

Question 15

The second law of thermodynamics states that

Accepted Answer

The second law of thermodynamics states that in any spontaneous process, the entropy of the universe increases. Entropy is a measure of the disorder or randomness in a system. Therefore, the second law implies that in any spontaneous process, there is an increase in disorder or randomness.

Question 16

Which of the following reactions would be expected to have a positive entropy change, ∆S1U1B1rS1U1B0S° > 0? 1. 2 SO2(g) + O2(g) → 2 SO3(g) 2. Ba(OH)2(s) → BaO(s) + H2O(g) 3. CO(g)+ 2 H₂(g)$\to$CH₃OH( )

Accepted Answer

The answer of Which of the following reactions would be...

Question 17

Arrange the following reactions in order of increasing $\Delta$_rS° value. 1.H₂(g)+ F₂(g)$\to$ 2HF(g) 2)NH₄NO₃(s)$\to$ N₂O(g)+ 2H₂O(l) 3)(NH₄)₂Cr₂O₇(s)$\to$ Cr₂O₃(s)+ 4H₂O(l)+ N₂(g)

Accepted Answer

The correct order is 1 < 3 < 2. This is because the F1F1F1S1F1F1F10_rS° value is a measure of the spontaneity of a reaction. The more positive the F1F1F1S1F1F1F10_rS° value, the more spontaneous the reaction. In this case, reaction 1 has the smallest F1F1F1S1F1F1F10_rS° value, followed by reaction 3 and then reaction 2.

Question 18

What is the change in entropy for a system going from 189 possible microstates to 734 possible microstates? (k = 1.381 F1F1F1S1F1F1F10 10^-23 J/K)

Accepted Answer

The answer of What is the change in entropy for...

Question 19

Which of the following statements concerning entropy is/are CORRECT?
1)The entropy of a substance increases when converted from a liquid to a solid.
2)The entropy of a substance decreases as its temperature increases.
3)All substances have positive entropy values at temperatures above 0 K.

Accepted Answer

Entropy generally increases when a substance transitions from a solid to a liquid, not the other way around. Entropy increases with temperature. All substances have positive entropy above 0 K.

Question 20

Which of the following statements regarding the spontaneity of chemical and physical changes is correct?

Accepted Answer

The answer of Which of the following statements regarding the...

Quiz 19: Entropy and Free Energy

As defined by Ludwig Boltzmann,the third law of thermodynamics states that

A statement of the first law of thermodynamics is that

Which of the following linear chain alcohols is likely to have the highest standard entropy in the liquid state?

In which reaction is $\Delta$ _rS° expected to be negative?

If a chemical reaction occurs in a direction that has a positive change in entropy then

Which of the following changes lead to a $\underline{\text{ decrease }}$ in entropy?

Which of the following compounds has the highest standard entropy per mole at 298 K?

When a chemical process occurs under standard conditions,which of the following conditions always apply? 1) Gaseous species are at a pressure of 1 bar. 2) Solution concentrations species are 1 molal. 3) The temperature is 298.15 K.

Which of the following statements is/are CORRECT? 1) Spontaneous changes only occur in the direction that leads to equilibrium. 2) Exothermic reactions are always spontaneous. 3) In any chemical reaction,energy must be conserved.

Which of the following statements concerning entropy is $\underline{\text{ not }}$ correct?

For a certain reversible process q = 57.40 kJ at 36.6^$\circ$C.What is $\Delta$ S for the process?

For which of the following reactions will the entropy of the system decrease?

The second law of thermodynamics states that

Arrange the following reactions in order of increasing $\Delta$ _rS° value. 1.H₂(g) + F₂(g) $\to$ 2HF(g) 2) NH₄NO₃(s) $\to$ N₂O(g) + 2H₂O(l) 3) (NH₄) ₂Cr₂O₇(s) $\to$ Cr₂O₃(s) + 4H₂O(l) + N₂(g)

What is the change in entropy for a system going from 189 possible microstates to 734 possible microstates? (k = 1.381  10^-23 J/K)

Which of the following statements concerning entropy is/are CORRECT? 1) The entropy of a substance increases when converted from a liquid to a solid. 2) The entropy of a substance decreases as its temperature increases. 3) All substances have positive entropy values at temperatures above 0 K.

Which of the following statements regarding the spontaneity of chemical and physical changes is correct?

Quiz 19: Entropy and Free Energy

As defined by Ludwig Boltzmann,the third law of thermodynamics states that

A statement of the first law of thermodynamics is that

Which of the following linear chain alcohols is likely to have the highest standard entropy in the liquid state?

In which reaction is Δ\DeltaΔ rS° expected to be negative?

If a chemical reaction occurs in a direction that has a positive change in entropy then

Which of the following changes lead to a decrease ‾\underline{\text{ decrease }} decrease ​ in entropy?

Which of the following statements concerning entropy change is/are true? 1) For a reversible process, ) 2) For a spontaneous process, ) 3) For a reversible process,such as a phase change, Δ\DeltaΔ S = qrev/T .

Which of the following compounds has the highest standard entropy per mole at 298 K?

When a chemical process occurs under standard conditions,which of the following conditions always apply? 1) Gaseous species are at a pressure of 1 bar. 2) Solution concentrations species are 1 molal. 3) The temperature is 298.15 K.

Which of the following statements is/are CORRECT? 1) Spontaneous changes only occur in the direction that leads to equilibrium. 2) Exothermic reactions are always spontaneous. 3) In any chemical reaction,energy must be conserved.

Which of the following statements concerning entropy is not ‾\underline{\text{ not }} not ​ correct?

For a certain reversible process q = 57.40 kJ at 36.6 ∘\circ∘ C.What is Δ\DeltaΔ S for the process?

For which of the following reactions will the entropy of the system decrease?

The second law of thermodynamics states that

Which of the following reactions would be expected to have a positive entropy change, ∆rS° > 0? 1. 2 SO2(g) + O2(g) → 2 SO3(g) 2. Ba(OH) 2(s) → BaO(s) + H2O(g) 3. CO(g) + 2 H2(g) →\to→ CH3OH( )

Arrange the following reactions in order of increasing Δ\DeltaΔ rS° value. 1.H2(g) + F2(g) →\to→ 2HF(g) 2) NH4NO3(s) →\to→ N2O(g) + 2H2O(l) 3) (NH4) 2Cr2O7(s) →\to→ Cr2O3(s) + 4H2O(l) + N2(g)

What is the change in entropy for a system going from 189 possible microstates to 734 possible microstates? (k = 1.381  10-23 J/K)

Which of the following statements concerning entropy is/are CORRECT? 1) The entropy of a substance increases when converted from a liquid to a solid. 2) The entropy of a substance decreases as its temperature increases. 3) All substances have positive entropy values at temperatures above 0 K.

Which of the following statements regarding the spontaneity of chemical and physical changes is correct?

In which reaction is $\Delta$ _rS° expected to be negative?

Which of the following changes lead to a $\underline{\text{ decrease }}$ in entropy?

Which of the following statements concerning entropy is $\underline{\text{ not }}$ correct?

For a certain reversible process q = 57.40 kJ at 36.6^$\circ$C.What is $\Delta$ S for the process?

Arrange the following reactions in order of increasing $\Delta$ _rS° value. 1.H₂(g) + F₂(g) $\to$ 2HF(g) 2) NH₄NO₃(s) $\to$ N₂O(g) + 2H₂O(l) 3) (NH₄) ₂Cr₂O₇(s) $\to$ Cr₂O₃(s) + 4H₂O(l) + N₂(g)

What is the change in entropy for a system going from 189 possible microstates to 734 possible microstates? (k = 1.381  10^-23 J/K)