Question 1

Consider the following reaction for the combustion of ethane (C ₂H ₆): C₂H₆( g )+ O₂( g )→ CO₂( g )+ H₂O( l ). If Δ G ° (in kJ\moles)for C ₂H ₆( g )is − 32.9, for O ₂( g )is 0, for CO ₂( g )is − 394.4, and for H ₂O( l )is − 237.2; calculate Δ G ° for the reaction.

Accepted Answer

The answer of Consider the following reaction for the combustion...

Question 2

The second law of thermodynamics states that in any spontaneous process, the total entropy change of the universe is positive.

Accepted Answer

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time, and for any spontaneous process, the entropy of the universe increases, making the total entropy change positive.

Question 3

When magnesium sulfite decomposes, the solid transforms into magnesium oxide and sulfur dioxide. The reaction is as follows: MgSO ₃( s )→ MgO( s )+ SO ₂( g ) According to the Gibbs free energy, at what temperature will this reaction be spontaneous? Δ G in kJ\moles for MgSO ₃( s )is − 1172, for MgO( s )is − 569.6, and for SO ₂( g )is − 300.2. Δ H in kJ\moles for MgSO ₃( s )is − 1068, for MgO( s )is − 601.8, and for SO ₂( g )is − 296.8. Δ S in J\moles K for MgSO ₃( s )is 121, for MgO( s )is 27, and for SO ₂( g )is 248.1.

Accepted Answer

The answer of When magnesium sulfite decomposes, the solid transforms...

Question 4

Calculate Δ G° for the following reaction: 2 NO ₂( g )→ N ₂( g )+ 2 O ₂( g ). Δ G _f° in kJ\moles for NO ₂( g )is 51.30.

Accepted Answer

The reaction involves the decomposition of 2 moles of NO₂(g) into N₂(g) and O₂(g). Since ΔG°f for NO₂(g) is given as 51.30 kJ/mol, for 2 moles it would be 2 * 51.30 = 102.6 kJ. The products N₂(g) and O₂(g) are elements in their standard states, so their ΔG°f is 0. Therefore, ΔG° for the reaction is 0 - 102.6 = -102.6 kJ, which is approximately -103 kJ.

Question 5

Calculate Δ G° for the following reaction: SO₃( g )+ CaO( s )→ CaSO₄( s ). Δ G _f° in kJ\moles for CaO( s )is − 604.2, for SO ₃( g )is − 371.1, and for CaSO ₄( s )is − 1320.

Accepted Answer

The answer of Calculate Δ G° for the following reaction:...

Question 6

Calculate Δ S° for the following reaction: 2 SO₃( g )→ 2 SO₂( g )+ O₂( g ). Δ S° in J\moles K for SO ₂( g )is 248.1, for SO ₃( g )is 256.6, and for O ₂( g )is 205.0.

Accepted Answer

ΔS° = ΣS°(products) - ΣS°(reactants) = [2(248.1) + 205.0] - [2(256.6)] = 701.2 - 513.2 = +188 J/mol K.

Question 7

What is the melting point of polyvinyl chloride if the heat of fusion of crystalline polyvinyl chloride is approximately 11.0 kJ\moles, and the corresponding entropy change for melting is 68.75 J moles ^{− 1}K ^{− 1}?

Accepted Answer

The answer of What is the melting point of polyvinyl...

Question 8

In the context of free energy and work, the amount of work available in an irreversible change is always less than 
the maximum work.

Accepted Answer

In an irreversible process, some energy is dissipated as heat, making the work done less than the maximum possible work, which is only achieved in a reversible process.

Question 9

Calculate Δ G° for the following reaction: 2 SO₃( g )→ 2 SO₂( g )+ O₂( g ) Δ G _f° in kJ\moles for SO ₂( g )is − 300.2, and for SO ₃( g )is − 371.1.

Accepted Answer

The answer of Calculate Δ G° for the following reaction:...

Question 10

Which of the following is an example of a state function?

Accepted Answer

Temperature is a state function because it depends only on the current state of the system, not on the path taken to reach that state.

Question 11

Calculate Δ S° for the following reaction: SO₃( g )+ CaO( s )→ CaSO₄( s ). Δ S° in J\moles K for CaO( s )is 40, for SO ₃( g )is 256.6, and for CaSO ₄( s )is 107.

Accepted Answer

The answer of Calculate Δ S° for the following reaction:...

Question 12

The degradation of phosgene (COCl ₂)into CO and Cl ₂is not spontaneous at room temperature and standard state conditions (273 K, 1 atm). Which of the following can make this a spontaneous reaction?

Accepted Answer

Increasing the temperature can make an endothermic reaction spontaneous by providing the necessary energy to overcome the activation energy barrier.

Question 13

A reaction that has a positive Δ H and a negative Δ S is spontaneous at all temperatures.

Accepted Answer

A reaction with a positive ΔH (endothermic) and a negative ΔS (decrease in entropy) is non-spontaneous at all temperatures because both factors oppose spontaneity.

Question 14

Calculate Δ S° for the following reaction: 2 NO ₂( g )→ N ₂( g )+ 2 O ₂( g ). Δ S° in J\moles K for NO ₂( g )is 240.0, for N ₂( g )is 191.5, and for O ₂( g )is 205.0.

Accepted Answer

The answer of Calculate Δ S° for the following reaction:
2...

Question 15

Consider the following reaction of carbon monoxide with oxygen to produce carbon dioxide. 2 CO( g )+ O₂( g )→ 2 CO₂( g ) At what temperature will this reaction be spontaneous according to Gibbs free energy? Δ H in kJ\moles for CO( g )is − 110.5 and for CO ₂( g )is − 393.5. Δ S in J\moles K for CO( g )is 197.6, and for CO ₂( g )is 213.6, O ₂( g )= 205.0.

Accepted Answer

The answer of Consider the following reaction of carbon monoxide...

Quiz 10: Entropy and the Second Law of Thermodynamics

The second law of thermodynamics states that in any spontaneous process, the total entropy change of the universe is positive.

Calculate Δ G° for the following reaction: 2 NO ₂( g ) → N ₂( g ) + 2 O ₂( g ) . Δ G _f° in kJ\moles for NO ₂( g ) is 51.30.

Calculate Δ G° for the following reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) . Δ G _f° in kJ\moles for CaO( s ) is − 604.2, for SO ₃( g ) is − 371.1, and for CaSO ₄( s ) is − 1320.

Calculate Δ S° for the following reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) . Δ S° in J\moles K for SO ₂( g ) is 248.1, for SO ₃( g ) is 256.6, and for O ₂( g ) is 205.0.

What is the melting point of polyvinyl chloride if the heat of fusion of crystalline polyvinyl chloride is approximately 11.0 kJ\moles, and the corresponding entropy change for melting is 68.75 J moles ^{− 1}K ^{− 1}?

In the context of free energy and work, the amount of work available in an irreversible change is always less than the maximum work.

Calculate Δ G° for the following reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) Δ G _f° in kJ\moles for SO ₂( g ) is − 300.2, and for SO ₃( g ) is − 371.1.

Which of the following is an example of a state function?

Calculate Δ S° for the following reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) . Δ S° in J\moles K for CaO( s ) is 40, for SO ₃( g ) is 256.6, and for CaSO ₄( s ) is 107.

The degradation of phosgene (COCl ₂) into CO and Cl ₂is not spontaneous at room temperature and standard state conditions (273 K, 1 atm) . Which of the following can make this a spontaneous reaction?

A reaction that has a positive Δ H and a negative Δ S is spontaneous at all temperatures.

Calculate Δ S° for the following reaction: 2 NO ₂( g ) → N ₂( g ) + 2 O ₂( g ) . Δ S° in J\moles K for NO ₂( g ) is 240.0, for N ₂( g ) is 191.5, and for O ₂( g ) is 205.0.

Quiz 10: Entropy and the Second Law of Thermodynamics

The second law of thermodynamics states that in any spontaneous process, the total entropy change of the universe is positive.

Calculate Δ G° for the following reaction: 2 NO 2 ( g ) → N 2 ( g ) + 2 O 2 ( g ) . Δ G f ° in kJ\moles for NO 2 ( g ) is 51.30.

Calculate Δ G° for the following reaction: ​ SO3( g ) + CaO( s ) → CaSO4( s ) . ​ Δ G f ° in kJ\moles for CaO( s ) is − 604.2, for SO 3 ( g ) is − 371.1, and for CaSO 4 ( s ) is − 1320.

Calculate Δ S° for the following reaction: ​ 2 SO3( g ) → 2 SO2( g ) + O2( g ) . ​ Δ S° in J\moles K for SO 2 ( g ) is 248.1, for SO 3 ( g ) is 256.6, and for O 2 ( g ) is 205.0.

What is the melting point of polyvinyl chloride if the heat of fusion of crystalline polyvinyl chloride is approximately 11.0 kJ\moles, and the corresponding entropy change for melting is 68.75 J moles − 1 K − 1 ?

In the context of free energy and work, the amount of work available in an irreversible change is always less than the maximum work.

Calculate Δ G° for the following reaction: ​ 2 SO3( g ) → 2 SO2( g ) + O2( g ) ​ Δ G f ° in kJ\moles for SO 2 ( g ) is − 300.2, and for SO 3 ( g ) is − 371.1.

Which of the following is an example of a state function?

Calculate Δ S° for the following reaction: ​ SO3( g ) + CaO( s ) → CaSO4( s ) . ​ Δ S° in J\moles K for CaO( s ) is 40, for SO 3 ( g ) is 256.6, and for CaSO 4 ( s ) is 107.

The degradation of phosgene (COCl 2 ) into CO and Cl 2 is not spontaneous at room temperature and standard state conditions (273 K, 1 atm) . Which of the following can make this a spontaneous reaction?

A reaction that has a positive Δ H and a negative Δ S is spontaneous at all temperatures.

Calculate Δ S° for the following reaction: 2 NO 2 ( g ) → N 2 ( g ) + 2 O 2 ( g ) . Δ S° in J\moles K for NO 2 ( g ) is 240.0, for N 2 ( g ) is 191.5, and for O 2 ( g ) is 205.0.

Calculate Δ G° for the following reaction: 2 NO ₂( g ) → N ₂( g ) + 2 O ₂( g ) . Δ G _f° in kJ\moles for NO ₂( g ) is 51.30.

Calculate Δ G° for the following reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) . Δ G _f° in kJ\moles for CaO( s ) is − 604.2, for SO ₃( g ) is − 371.1, and for CaSO ₄( s ) is − 1320.

Calculate Δ S° for the following reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) . Δ S° in J\moles K for SO ₂( g ) is 248.1, for SO ₃( g ) is 256.6, and for O ₂( g ) is 205.0.

What is the melting point of polyvinyl chloride if the heat of fusion of crystalline polyvinyl chloride is approximately 11.0 kJ\moles, and the corresponding entropy change for melting is 68.75 J moles ^{− 1}K ^{− 1}?

Calculate Δ G° for the following reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) Δ G _f° in kJ\moles for SO ₂( g ) is − 300.2, and for SO ₃( g ) is − 371.1.

Calculate Δ S° for the following reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) . Δ S° in J\moles K for CaO( s ) is 40, for SO ₃( g ) is 256.6, and for CaSO ₄( s ) is 107.

The degradation of phosgene (COCl ₂) into CO and Cl ₂is not spontaneous at room temperature and standard state conditions (273 K, 1 atm) . Which of the following can make this a spontaneous reaction?

Calculate Δ S° for the following reaction: 2 NO ₂( g ) → N ₂( g ) + 2 O ₂( g ) . Δ S° in J\moles K for NO ₂( g ) is 240.0, for N ₂( g ) is 191.5, and for O ₂( g ) is 205.0.