Question 1

The entropy change for the following reaction will be positive:
N2 (g) + 3 H2 (g) → 2 NH3 (g)

Accepted Answer

A) True 
 B)False  False

Question 2

Whether the total entropy change (ΔSS1U1B1(S1U1B0S1U1B1total)S1U1B0) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the (ΔSS1U1B1(total)S1U1B0) condition with its description.
-ΔS(total) = 0

Accepted Answer

A)  spontaneous process 
B)  non-spontaneous process 
C)  process at equilibrium 
A)  spontaneous process 
B)  non-spontaneous process 
C)  process at equilibrium C

Question 3

Match the reaction description and whether it is spontaneous and under which conditions
-ΔH > 0, ΔS < 0

Accepted Answer

A)  Never spontaneous 
B)  Spontaneous on heating 
C)  Always spontaneous 
D)  Spontaneous on cooling 
A)  Never spontaneous 
B)  Spontaneous on heating 
C)  Always spontaneous 
D)  Spontaneous on cooling A

Question 4

Match the reaction description and whether it is spontaneous and under which conditions
-ΔH  0

Accepted Answer

A)  Never spontaneous 
B)  Spontaneous on heating 
C)  Always spontaneous 
D)  Spontaneous on cooling 
A)  Never spontaneous 
B)  Spontaneous on heating 
C)  Always spontaneous 
D)  Spontaneous on cooling

Question 5

Calculate the entropy change ( $\triangle_{fus} S^{∘}$ , J K-1 mol-1) when 1.00 mol of methane at its melting point (Tm = - 182.05 °C) freezes (in the process the temperature does not change and $\triangle_{fus} H^{∘}$ for methane is + 0.94 kJ mol-1).

Accepted Answer

A)  - 10.3. 
B)  - 0.01. 
C)  + 10.3. 
D)  - 5.2. 
A)  - 10.3. 
B)  - 0.01. 
C)  + 10.3. 
D)  - 5.2.

Question 6

The standard entropy $S_{298}^{∘}$ of ethanol, at 1 bar, is 159.9 J K-1 mol-1. At 315 K, its standard entropy will be larger.

Accepted Answer

A) True 
 B)False

Question 7

Entropy is identified with the amount of ________ in the system.

Accepted Answer

The answer of Entropy is identified with the amount of...

Question 8

The standard entropy change for the following reaction will be large and positive. CS2 (l) + 3O2 (g) → CO2 (g) + 2SO2 (g)

Accepted Answer

A) True 
 B)False

Question 9

An endothermic reaction has $\mathrm{D}_{\mathrm{r}} \mathrm{H}_{298}^{\circ}=+389.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$ , $D_{1} S_{298}^{\circ}=+497.2 \mathrm{JK}^{-1} \mathrm{mol}^{-1}$ and $D_{1} G_{298}^{\circ}=+241.3 \mathrm{~kJ} m ol^{-1}$ . Find the temperature, T(K), at which the reaction becomes spontaneous.

Accepted Answer

A)  298. 
B)  783. 
C)  0.78. 
D)  1.28. 
A)  298. 
B)  783. 
C)  0.78. 
D)  1.28.

Question 10

Whether the total entropy change (ΔSS1U1B1(S1U1B0S1U1B1total)S1U1B0) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the (ΔSS1U1B1(total)S1U1B0) condition with its description.
-ΔS(total) > 0

Accepted Answer

A)  spontaneous process 
B)  non-spontaneous process 
C)  process at equilibrium 
A)  spontaneous process 
B)  non-spontaneous process 
C)  process at equilibrium

Question 11

Using the data given below estimate the value of the Gibbs energy change of reaction at 325 K, for the following reaction:
N2 (g) + 2 O2 (g) → 2 NO2 (g)
$\begin{array}{|l|c|c|c|}
\hline & \mathrm{N}_{2}(\mathrm{~g}) & \mathrm{O}_{2}(\mathrm{~g}) & \mathrm{NO}_{2}(\mathrm{~g}) \
\hline \Delta_{\mathrm{f}} H_{298}^{\circ} / \mathrm{kJ} \mathrm{mol}^{-1} & 0 & 0 & +33.2 \
\hline S_{298}^{\circ} / \mathrm{J} \mathrm{K}^{-1} \mathrm{~mol}^{-1} & 191.6 & 205.1 & 240.1 \
\hline C_{\mathrm{p}} / \mathrm{JK}^{-1} \mathrm{~mol}^{-1} & 29.1 & 29.4 & 37.2 \
\hline
\end{array}$

Accepted Answer

A)  + 26.1. 
B)  + 105.9. 
C)  + 102.6. 
D)  + 40. 
A)  + 26.1. 
B)  + 105.9. 
C)  + 102.6. 
D)  + 40.

Question 12

Whether the total entropy change (ΔSS1U1B1(S1U1B0S1U1B1total)S1U1B0) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the (ΔSS1U1B1(total)S1U1B0) condition with its description.
-ΔS(total) < 0

Accepted Answer

A)  spontaneous process 
B)  non-spontaneous process 
C)  process at equilibrium 
A)  spontaneous process 
B)  non-spontaneous process 
C)  process at equilibrium

Question 13

The standard entropy change, $\triangle_{T} S_{298}^{∘}$ for the following reaction is: + 511.9 J K-1 mol-1.
C12H22O11 (s) + 12 O2 (g) → 12 CO2 (g) + 11 H2O (l) Calculate the standard entropy change of reaction $\triangle_{T} S ^{∘}$ (in J K-1 mol-1) at 390 116.85 °C.

Accepted Answer

A)  + 511.9. 
B)  + 48.3. 
C)  + 379. 
D)  + 645. 
A)  + 511.9. 
B)  + 48.3. 
C)  + 379. 
D)  + 645.

Question 14

Using $\Delta _{f}G_{298}^{\circ}$ data given below:
$\begin{array}{|c|c|c|c|c|}
\hline & \mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}(\mathrm{~s}) & \mathrm{O}_{2}(\mathrm{~g}) & \mathrm{CO}_{2}(\mathrm{~g}) & \mathrm{H}_{2} \mathrm{O}(\mathrm{l}) \
\hline \Delta_{\mathrm{f}} G_{298}^{\circ} / \mathrm{kJ} \mathrm{mol}^{-1} & -1543 & 0 & -394.4 & -237.1 \
\hline
\end{array}$
Calculate the standard Gibbs energy change, $\Delta _{T}G_{298}^{\circ}$ (kJ mol-1), for the following reaction:
C12H22O11 (s) + 12 O2 (g) → 12 CO2 (g) + 11 H2O (l)

Accepted Answer

A)  + 911.5. 
B)  - 5797.9. 
C)  + 5797.9. 
D)  - 911.5. 
A)  + 911.5. 
B)  - 5797.9. 
C)  + 5797.9. 
D)  - 911.5.

Question 15

Using $\Delta_{f} G_{298}^{\circ}$ data given below:
$\begin{array}{|c|c|c|c|}
\hline & \mathrm{CO}(\mathrm{g}) & \mathrm{H}_{2}(\mathrm{~g}) & \mathrm{CH}_{3} \mathrm{OH}(\mathrm{g}) \
\hline \Delta_{\mathrm{f}} G_{298}^{\circ} / \mathrm{kJ} \mathrm{mol}^{-1} & -137.2 & 0 & -162.0 \
\hline
\end{array}$
Calculate the standard Gibbs energy change, $\Delta_{f} G_{298}^{\circ}$ (kJ mol-1), for the following reaction:
CO (g) + 2 H2 (g) → CH3OH (g)

Accepted Answer

A)  - 299.2. 
B)  + 299.2. 
C)  + 24.8. 
D)  - 24.8. 
A)  - 299.2. 
B)  + 299.2. 
C)  + 24.8. 
D)  - 24.8.

Question 16

Calculate the standard entropy $S_{\mathrm{T}}^{∘}$ of 1 mol of water at 20 °C and 1 bar. The molar heat capacity, Cp, of water is 75.3 J K-1 mol-1 and $S_{298}^{∘}$ is 69.9 J K-1 mol-1.

Accepted Answer

A)  69.9. 
B)  - 133.5. 
C)  68.7. 
D)  71.1. 
A)  69.9. 
B)  - 133.5. 
C)  68.7. 
D)  71.1.

Question 17

Calculate the entropy change ( $\triangle_{vap} S^{∘}$ , J K-1 mol-1) when 1.00 mol of ethanol at its boiling point (Tb =78.45 °C) vaporizes (in the process the temperature does not change, $\triangle_{vap} H^{∘}$	 for ethanol is + 43.5 kJ mol-1).

Accepted Answer

A)  + 124. 
B)  - 124. 
C)  + 554. 
D)  + 0.12. 
A)  + 124. 
B)  - 124. 
C)  + 554. 
D)  + 0.12.

Question 18

Whether Gibbs energy change (ΔG) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the situation with its description.
-ΔG < 0

Accepted Answer

A)  the reaction or process is spontaneous 
B)  the reaction or process is non-spontaneous 
C)  the reaction or process is at equilibrium 
A)  the reaction or process is spontaneous 
B)  the reaction or process is non-spontaneous 
C)  the reaction or process is at equilibrium

Question 19

Using data in Appendix 7, (p. 1350), calculate the standard entropy change of reaction $\triangle_{T} S_{298}^{∘}$ (in J K-1 mol-1) for the following reaction:
NH3 (g) + HNO3 (l) → NH4NO3 (s)

Accepted Answer

A)  - 197. 
B)  + 197. 
C)  -151.1. 
D)  +151.1. 
A)  - 197. 
B)  + 197. 
C)  -151.1. 
D)  +151.1.

Question 20

For water $\triangle_{vap} S^{∘}$ = + 109 J K-1 mol-1 whilst $\triangle_{fus} S^{∘}$ = + 22 J K-1 mol-1. The entropy change for vaporization is larger than the entropy change for fusion because it is measured at a higher temperature.

Accepted Answer

A) True 
 B)False

Exam 14: Entropy and Gibbs Energy

The entropy change for the following reaction will be positive: N2 (g) + 3 H2 (g) → 2 NH3 (g)

Whether the total entropy change (ΔS(total)) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the (ΔS(total)) condition with its description. -ΔS(total) = 0

Match the reaction description and whether it is spontaneous and under which conditions -ΔH > 0, ΔS < 0

Match the reaction description and whether it is spontaneous and under which conditions -ΔH < 0, ΔS > 0

Calculate the entropy change ( △fusS∘\triangle_{fus} S^{∘}△fus​S∘ , J K-1 mol-1) when 1.00 mol of methane at its melting point (Tm = - 182.05 °C) freezes (in the process the temperature does not change and △fusH∘\triangle_{fus} H^{∘}△fus​H∘ for methane is + 0.94 kJ mol-1).

The standard entropy S298∘S_{298}^{∘}S298∘​ of ethanol, at 1 bar, is 159.9 J K-1 mol-1. At 315 K, its standard entropy will be larger.

Entropy is identified with the amount of ________ in the system.

The standard entropy change for the following reaction will be large and positive. CS2 (l) + 3O2 (g) → CO2 (g) + 2SO2 (g)

Whether the total entropy change (ΔS(total)) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the (ΔS(total)) condition with its description. -ΔS(total) > 0

Using the data given below estimate the value of the Gibbs energy change of reaction at 325 K, for the following reaction: N2 (g) + 2 O2 (g) → 2 NO2 (g) () () () / 0 0 +33.2 / 191.6 205.1 240.1 / 29.1 29.4 37.2

Whether the total entropy change (ΔS(total)) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the (ΔS(total)) condition with its description. -ΔS(total) < 0

Using ΔfG298∘\Delta_{f} G_{298}^{\circ}Δf​G298∘​ data given below: () () () / -137.2 0 -162.0 Calculate the standard Gibbs energy change, ΔfG298∘\Delta_{f} G_{298}^{\circ}Δf​G298∘​ (kJ mol-1), for the following reaction: CO (g) + 2 H2 (g) → CH3OH (g)

Calculate the standard entropy ST∘S_{\mathrm{T}}^{∘}ST∘​ of 1 mol of water at 20 °C and 1 bar. The molar heat capacity, Cp, of water is 75.3 J K-1 mol-1 and S298∘S_{298}^{∘}S298∘​ is 69.9 J K-1 mol-1.

Calculate the entropy change ( △vapS∘\triangle_{vap} S^{∘}△vap​S∘ , J K-1 mol-1) when 1.00 mol of ethanol at its boiling point (Tb =78.45 °C) vaporizes (in the process the temperature does not change, △vapH∘\triangle_{vap} H^{∘}△vap​H∘ for ethanol is + 43.5 kJ mol-1).

Whether Gibbs energy change (ΔG) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the situation with its description. -ΔG < 0

Using data in Appendix 7, (p. 1350), calculate the standard entropy change of reaction △TS298∘\triangle_{T} S_{298}^{∘}△T​S298∘​ (in J K-1 mol-1) for the following reaction: NH3 (g) + HNO3 (l) → NH4NO3 (s)

For water △vapS∘\triangle_{vap} S^{∘}△vap​S∘ = + 109 J K-1 mol-1 whilst △fusS∘\triangle_{fus} S^{∘}△fus​S∘ = + 22 J K-1 mol-1. The entropy change for vaporization is larger than the entropy change for fusion because it is measured at a higher temperature.

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The entropy change for the following reaction will be positive: N₂ (g) + 3 H₂ (g) → 2 NH₃ (g)

Whether the total entropy change (ΔS₍_total)) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the (ΔS_(total)) condition with its description. -ΔS_(total) = 0

Calculate the entropy change ( $\triangle_{fus} S^{∘}$ , J K^-1 mol^-1) when 1.00 mol of methane at its melting point (T_m = - 182.05 °C) freezes (in the process the temperature does not change and $\triangle_{fus} H^{∘}$ for methane is + 0.94 kJ mol^-1).

The standard entropy $S_{298}^{∘}$ of ethanol, at 1 bar, is 159.9 J K^-1 mol^-1. At 315 K, its standard entropy will be larger.

The standard entropy change for the following reaction will be large and positive. CS₂ (l) + 3O₂ (g) → CO₂ (g) + 2SO₂ (g)

Whether the total entropy change (ΔS₍_total)) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the (ΔS_(total)) condition with its description. -ΔS_(total) > 0

Using the data given below estimate the value of the Gibbs energy change of reaction at 325 K, for the following reaction: N₂ (g) + 2 O₂(g) → 2 NO₂ (g) () () () / 0 0 +33.2 / 191.6 205.1 240.1 / 29.1 29.4 37.2

Whether the total entropy change (ΔS₍_total)) of a process is positive, negative, or equal to zero defines whether the process is spontaneous. Match the (ΔS_(total)) condition with its description. -ΔS_(total) < 0

Using $\Delta_{f} G_{298}^{\circ}$ data given below: () () () / -137.2 0 -162.0 Calculate the standard Gibbs energy change, $\Delta_{f} G_{298}^{\circ}$ (kJ mol^-1), for the following reaction: CO (g) + 2 H₂ (g) → CH₃OH (g)

Calculate the standard entropy $S_{\mathrm{T}}^{∘}$ of 1 mol of water at 20 °C and 1 bar. The molar heat capacity, C_p, of water is 75.3 J K^-1 mol^-1 and $S_{298}^{∘}$ is 69.9 J K^-1 mol^-1.

Calculate the entropy change ( $\triangle_{vap} S^{∘}$ , J K^-1 mol^-1) when 1.00 mol of ethanol at its boiling point (T_b =78.45 °C) vaporizes (in the process the temperature does not change, $\triangle_{vap} H^{∘}$ for ethanol is + 43.5 kJ mol^-1).

Using data in Appendix 7, (p. 1350), calculate the standard entropy change of reaction $\triangle_{T} S_{298}^{∘}$ (in J K^-1 mol^-1) for the following reaction: NH₃ (g) + HNO₃ (l) → NH₄NO₃ (s)

For water $\triangle_{vap} S^{∘}$ = + 109 J K^-1 mol^-1 whilst $\triangle_{fus} S^{∘}$ = + 22 J K^-1 mol^-1. The entropy change for vaporization is larger than the entropy change for fusion because it is measured at a higher temperature.