Question 1

When calculating the entropy change as a result of transferring heat reversibly to or from a system,the temperature must be constant.

Accepted Answer

The formula for calculating the entropy change as a result of heat transfer is ∆S=q/T, where T is the constant temperature at which the transfer occurs. Therefore, the temperature must be constant in order for this formula to be valid.

Question 2

Use tabulated thermodynamic data to calculate the concentration of CO₂(aq)in equilibrium with an external pressure of 2.50 atm CO₂(g)at 298 K.

Accepted Answer

The answer of Use tabulated thermodynamic data to calculate the...

Question 3

All the following compounds become less stable with respect to their elements as the temperature is raised except

Accepted Answer

The answer of All the following compounds become less stable...

Question 4

Consider the compounds PCl₅(g),HCN(g),CuO(s),NO(g),NH₃(g),and SO₂(g). Which compound will become more stable with respect to its elements if the temperature is raised?

Accepted Answer

The answer of Consider the compounds PCl₅(g),HCN(g),CuO(s),NO(g),NH₃(g),and SO₂(g). Which compound will...

Question 5

For the reaction 2NH₃(g)→ 3H₂(g)+ N₂(g),K_P = 1.47 *10^-6 at 298 K.Estimate the temperature at which K_P = 0.0100.

Accepted Answer

The answer of For the reaction 2NH₃(g)→ 3H₂(g)+ N₂(g),K_P =...

Question 6

Consider the compounds PCl₅(g),HCN(g),CuO(s),NO(g),NH₃(g),and SO₂(g). Which compound will become more stable with respect to its elements if the temperature is raised?

Accepted Answer

The answer of Consider the compounds PCl₅(g),HCN(g),CuO(s),NO(g),NH₃(g),and SO₂(g). Which compound will...

Question 7

The entropy of vaporization of a substance is always larger than its entropy of fusion.

Accepted Answer

When a substance goes from a liquid to a gas during vaporization, its molecules become more disordered and spread out, resulting in an increase in entropy. On the other hand, during fusion from a solid to a liquid, the molecules become more organized and closely packed together, resulting in a smaller increase in entropy. Therefore, the entropy of vaporization is typically greater than the entropy of fusion.

Question 8

The sublimation of solid carbon dioxide is a spontaneous process.Predict the sign (+,-,or 0)of $\Delta$G_rS1U1P1$\circ$S1S1P0,$\Delta$H_rS1U1P1$\circ$S1S1P0,and $\Delta$S_rS1U1P1$\circ$S1S1P0,respectively.

Accepted Answer

The sublimation of solid carbon dioxide is spontaneous, so $\Delta G^\circ$ is negative. The process requires heat input (endothermic), so $\Delta H^\circ$ is positive. The entropy increases as solid turns to gas, so $\Delta S^\circ$ is positive.

Question 9

When calculating the entropy of vaporization of water at 25S1U1P1$\circ$S1S1P0C,the dominant contribution is

Accepted Answer

The dominant contribution when calculating the entropy of vaporization of water at 25°C is the entropy of vaporization of water at its normal boiling point. This is because the process of vaporization involves breaking the intermolecular bonds between water molecules and requires a large input of energy, resulting in a significant increase in entropy. The contribution from heating and cooling the water is less significant in comparison.

Question 10

Which of the following statements is true?

Accepted Answer

A spontaneous process is one that occurs without external intervention and leads to a decrease in the system's free energy. Therefore, statement C is correct. Statement A is false, as the entropy of a compound is related to its structure and molecular motion. Statement B is false, as the molar entropy of liquid sulfur is much higher than that of ice. Statement D is incomplete and cannot be determined without additional information. Statement E is false, as some non-spontaneous processes may have positive changes in energy.

Question 11

Which of the following is true for a spontaneous reaction at constant temperature?

Accepted Answer

For a spontaneous reaction at constant temperature, the change in Gibbs free energy (ΔG) must be negative. Using the equation ΔG = ΔH - TΔS, we can see that for a spontaneous reaction, ΔH must be negative and TΔS must be positive. Therefore, the correct answer is D, which states that ΔH and -TΔS are both negative, leading to a negative value for ΔG. The other answer choices do not provide accurate or relevant information to determine the spontaneity of the reaction at constant temperature.

Question 12

An example of a spontaneous process having $\Delta$H ~ 0 is

Accepted Answer

Mixing of gases like helium and argon at constant temperature and pressure without a change in enthalpy is an example of a spontaneous process where $\Delta H$ is approximately zero.

Question 13

Calculate $\Delta$G for the process
He(g,1 atm,298 K)$\rightarrow$ He(g,10 atm,298 K)

Accepted Answer

The answer of Calculate $\Delta$G for the process
He(g,1 atm,298 K)$\rightarrow$...

Question 14

Which of the following statements is true?

Accepted Answer

A reaction's spontaneity in one direction implies non-spontaneity in the reverse direction due to the thermodynamic principle that if the forward reaction is spontaneous (negative ΔG), the reverse reaction must have a positive ΔG, making it non-spontaneous.

Question 15

Calculate the entropy of vaporization of water at 25S1U1P1$\circ$S1S1P0C and 1 bar.The molar heat capacities of the liquid and gas are 75 and 34 J·K^-1·mol^-1,respectively.The molar enthalpy of vaporization of water at its normal boiling point is 40.7 kJ·mol^-1.

Accepted Answer

The answer of Calculate the entropy of vaporization of water...

Question 16

Use tabulated thermodynamic data to estimate the temperature at which the vapor pressure of benzene is 1.33 kPa.Hint: Assume that the enthalpy and entropy of the reaction are independent of temperature.

Accepted Answer

The answer of Use tabulated thermodynamic data to estimate the...

Question 17

Consider the compounds PCl₅(g),HCN(g),CuO(s),NO(g),NH₃(g),and SO₂(g). Which compound will have approximately the same stability with respect to its elements if the temperature is raised?

Accepted Answer

NO(g) is known to have a standard enthalpy of formation close to zero, indicating that it is relatively stable with respect to its elements even when the temperature is raised.

Question 18

A piece of equipment must be capable of containing water at temperatures well above its normal boiling point.If the piece of equipment withstands an internal pressure of no more than 10.0 atm,calculate the highest temperature at which the system can be safely operated.

Accepted Answer

The answer of A piece of equipment must be capable...

Question 19

For the reaction 2SO₃(g)$\rightarrow$2SO₂(g)+ O₂(g) $\Delta$H_r° = +198 kJ.mol^-1 and $\Delta$S_r° = 190 J.K^-1.mol^-1 at 298 K.The equilibrium constant for this reaction will be greater than 1 at

Accepted Answer

The value of the enthalpy change for the reaction is +198 kJ, indicating that the reaction is endothermic. Therefore, an increase in temperature would favor the forward reaction to offset the added heat. The value of the entropy change for the reaction is positive (+190 J/K), indicating that the reaction proceeds with an increase in disorder or randomness. At temperatures above 1042 K, the increase in entropy would be expected to outweigh the increase in enthalpy, resulting in a positive value for the Gibbs free energy change and a Kc value greater than 1. Therefore, the equilibrium constant for this reaction will be greater than 1 at temperatures above 1042 K.

Question 20

$\Delta$U = 0 for the isothermal expansion of an ideal gas and therefore $\Delta$S = -w_rev/T = nRln(V₂/V₁).

Accepted Answer

This is the expression for the work done by an ideal gas during an isothermal expansion, and it follows from the first law of thermodynamics. Therefore, F1F1F1S1F1F1F10U = 0, and F1F1F1S1F1F1F10S = nRln(V₂/V₁) is a correct expression for the change in entropy.

Quiz 9: Thermodynamics: The Second and Third Laws

When calculating the entropy change as a result of transferring heat reversibly to or from a system,the temperature must be constant.

Use tabulated thermodynamic data to calculate the concentration of CO₂(aq)in equilibrium with an external pressure of 2.50 atm CO₂(g)at 298 K.

All the following compounds become less stable with respect to their elements as the temperature is raised except

Consider the compounds PCl₅(g) ,HCN(g) ,CuO(s) ,NO(g) ,NH₃(g) ,and SO₂(g) . Which compound will become more stable with respect to its elements if the temperature is raised?

For the reaction 2NH₃(g)→ 3H₂(g)+ N₂(g),K_P = 1.47 *10^-6 at 298 K.Estimate the temperature at which K_P = 0.0100.

Consider the compounds PCl₅(g) ,HCN(g) ,CuO(s) ,NO(g) ,NH₃(g) ,and SO₂(g) . Which compound will become more stable with respect to its elements if the temperature is raised?

The entropy of vaporization of a substance is always larger than its entropy of fusion.

The sublimation of solid carbon dioxide is a spontaneous process.Predict the sign (+,-,or 0) of $\Delta$ G_r^$\circ$, $\Delta$ H_r^$\circ$,and $\Delta$ S_r^$\circ$,respectively.

When calculating the entropy of vaporization of water at 25^$\circ$C,the dominant contribution is

Which of the following statements is true?

Which of the following is true for a spontaneous reaction at constant temperature?

An example of a spontaneous process having $\Delta$ H ~ 0 is

Calculate $\Delta$ G for the process He(g,1 atm,298 K) $\rightarrow$ He(g,10 atm,298 K)

Which of the following statements is true?

Calculate the entropy of vaporization of water at 25^$\circ$C and 1 bar.The molar heat capacities of the liquid and gas are 75 and 34 J·K^-1·mol^-1,respectively.The molar enthalpy of vaporization of water at its normal boiling point is 40.7 kJ·mol^-1.

Use tabulated thermodynamic data to estimate the temperature at which the vapor pressure of benzene is 1.33 kPa.Hint: Assume that the enthalpy and entropy of the reaction are independent of temperature.

Consider the compounds PCl₅(g) ,HCN(g) ,CuO(s) ,NO(g) ,NH₃(g) ,and SO₂(g) . Which compound will have approximately the same stability with respect to its elements if the temperature is raised?

A piece of equipment must be capable of containing water at temperatures well above its normal boiling point.If the piece of equipment withstands an internal pressure of no more than 10.0 atm,calculate the highest temperature at which the system can be safely operated.

For the reaction 2SO₃(g) $\rightarrow$ 2SO₂(g) + O₂(g) $\Delta$ H_r° = +198 kJ.mol^-1 and $\Delta$ S_r° = 190 J.K^-1.mol^-1 at 298 K.The equilibrium constant for this reaction will be greater than 1 at

$\Delta$ U = 0 for the isothermal expansion of an ideal gas and therefore $\Delta$ S = -w_rev/T = nRln(V₂/V₁).

Quiz 9: Thermodynamics: The Second and Third Laws

When calculating the entropy change as a result of transferring heat reversibly to or from a system,the temperature must be constant.

Use tabulated thermodynamic data to calculate the concentration of CO2(aq)in equilibrium with an external pressure of 2.50 atm CO2(g)at 298 K.

All the following compounds become less stable with respect to their elements as the temperature is raised except

Consider the compounds PCl5(g) ,HCN(g) ,CuO(s) ,NO(g) ,NH3(g) ,and SO2(g) . Which compound will become more stable with respect to its elements if the temperature is raised?

For the reaction 2NH3(g)→ 3H2(g)+ N2(g),KP = 1.47 *10-6 at 298 K.Estimate the temperature at which KP = 0.0100.

Consider the compounds PCl5(g) ,HCN(g) ,CuO(s) ,NO(g) ,NH3(g) ,and SO2(g) . Which compound will become more stable with respect to its elements if the temperature is raised?

The entropy of vaporization of a substance is always larger than its entropy of fusion.

The sublimation of solid carbon dioxide is a spontaneous process.Predict the sign (+,-,or 0) of Δ\DeltaΔ Gr ∘\circ∘ , Δ\DeltaΔ Hr ∘\circ∘ ,and Δ\DeltaΔ Sr ∘\circ∘ ,respectively.

When calculating the entropy of vaporization of water at 25 ∘\circ∘ C,the dominant contribution is

Which of the following statements is true?

Which of the following is true for a spontaneous reaction at constant temperature?

An example of a spontaneous process having Δ\DeltaΔ H ~ 0 is

Calculate Δ\DeltaΔ G for the process He(g,1 atm,298 K) →\rightarrow→ He(g,10 atm,298 K)

Which of the following statements is true?

Calculate the entropy of vaporization of water at 25 ∘\circ∘ C and 1 bar.The molar heat capacities of the liquid and gas are 75 and 34 J·K-1·mol-1,respectively.The molar enthalpy of vaporization of water at its normal boiling point is 40.7 kJ·mol-1.

Use tabulated thermodynamic data to estimate the temperature at which the vapor pressure of benzene is 1.33 kPa.Hint: Assume that the enthalpy and entropy of the reaction are independent of temperature.

Consider the compounds PCl5(g) ,HCN(g) ,CuO(s) ,NO(g) ,NH3(g) ,and SO2(g) . Which compound will have approximately the same stability with respect to its elements if the temperature is raised?

A piece of equipment must be capable of containing water at temperatures well above its normal boiling point.If the piece of equipment withstands an internal pressure of no more than 10.0 atm,calculate the highest temperature at which the system can be safely operated.

For the reaction 2SO3(g) →\rightarrow→ 2SO2(g) + O2(g) Δ\DeltaΔ Hr° = +198 kJ.mol-1 and Δ\DeltaΔ Sr° = 190 J.K-1.mol-1 at 298 K.The equilibrium constant for this reaction will be greater than 1 at

Δ\DeltaΔ U = 0 for the isothermal expansion of an ideal gas and therefore Δ\DeltaΔ S = -wrev/T = nRln(V2/V1).

Use tabulated thermodynamic data to calculate the concentration of CO₂(aq)in equilibrium with an external pressure of 2.50 atm CO₂(g)at 298 K.

Consider the compounds PCl₅(g) ,HCN(g) ,CuO(s) ,NO(g) ,NH₃(g) ,and SO₂(g) . Which compound will become more stable with respect to its elements if the temperature is raised?

For the reaction 2NH₃(g)→ 3H₂(g)+ N₂(g),K_P = 1.47 *10^-6 at 298 K.Estimate the temperature at which K_P = 0.0100.

Consider the compounds PCl₅(g) ,HCN(g) ,CuO(s) ,NO(g) ,NH₃(g) ,and SO₂(g) . Which compound will become more stable with respect to its elements if the temperature is raised?

The sublimation of solid carbon dioxide is a spontaneous process.Predict the sign (+,-,or 0) of $\Delta$ G_r^$\circ$, $\Delta$ H_r^$\circ$,and $\Delta$ S_r^$\circ$,respectively.

When calculating the entropy of vaporization of water at 25^$\circ$C,the dominant contribution is

An example of a spontaneous process having $\Delta$ H ~ 0 is

Calculate $\Delta$ G for the process He(g,1 atm,298 K) $\rightarrow$ He(g,10 atm,298 K)

Calculate the entropy of vaporization of water at 25^$\circ$C and 1 bar.The molar heat capacities of the liquid and gas are 75 and 34 J·K^-1·mol^-1,respectively.The molar enthalpy of vaporization of water at its normal boiling point is 40.7 kJ·mol^-1.

Consider the compounds PCl₅(g) ,HCN(g) ,CuO(s) ,NO(g) ,NH₃(g) ,and SO₂(g) . Which compound will have approximately the same stability with respect to its elements if the temperature is raised?

For the reaction 2SO₃(g) $\rightarrow$ 2SO₂(g) + O₂(g) $\Delta$ H_r° = +198 kJ.mol^-1 and $\Delta$ S_r° = 190 J.K^-1.mol^-1 at 298 K.The equilibrium constant for this reaction will be greater than 1 at

$\Delta$ U = 0 for the isothermal expansion of an ideal gas and therefore $\Delta$ S = -w_rev/T = nRln(V₂/V₁).