Question 1

Consider the combustion of ethane (C₂H₆): C₂H₆( g ) + O₂( g ) → CO₂( g ) + H₂O( l ) If Δ G ° (in kJ/mol) for: C₂H₆( g ) = − 32.9, O₂( g ) = 0, CO₂( g ) = − 394.4, and H₂O( l ) = − 237.2; calculate Δ G ° for the reaction.

Accepted Answer

ΔG° = ΣΔG°(products) - ΣΔG°(reactants)ΔG° = [ΔG°(CO2) + ΔG°(H2O)] - [ΔG°(C2H6) + ΔG°(O2)]ΔG° = [(-394.4 kJ/mol) + (-237.2 kJ/mol)] - [(-32.9 kJ/mol) + (0 kJ/mol)]ΔG° = -631.6 kJ/mol + 32.9 kJ/molΔG° = -598.7 kJ/mol

Question 2

Calculate Δ S for the reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) Δ S in J/mol K for: SO₂( g ) = 248.1, SO₃( g ) = 256.6, O₂( g ) = 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 3

Calculate Δ S for the reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) Δ S in J/mol K for: CaO( s ) = 40, SO₃( g ) = 256.6, CaSO₄( s ) = 107

Accepted Answer

The change in entropy (ΔS) for a reaction can be calculated using the formula ΔS = ΣS(products) - ΣS(reactants). For this reaction, ΔS = [107 J/mol K] - [256.6 + 40 J/mol K] = 107 - 296.6 = -189.6 J/mol K, which rounds to -190 J/K.

Question 4

Calculate Δ G for the reaction: 2 NO₂( g ) → 2 N₂( g ) + O₂( g ) Δ G in kJ/mol for: NO₂( g ) = 51.30

Accepted Answer

The reaction involves 2 moles of NO2, so ΔG = 2 * 51.30 = 102.6 kJ/mol, which is approximately -103 kJ/mol when considering the direction of the reaction.

Question 5

Calculate Δ G for the reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) Δ G in kJ/mol for: CaO( s ) = − 604.2, SO₃( g ) = − 371.1, CaSO₄( s ) = − 1320

Accepted Answer

The answer of Calculate Δ G for the reaction: SO₃( g...

Question 6

The degradation of phosgene (COCl₂) into CO and Cl₂ happens to be non-spontaneous at room temperature and standard state conditions (273 K, 1 atm). What change in temperature must occur to make this a spontaneous reaction?

Accepted Answer

For a reaction to become spontaneous, the Gibbs free energy change ($\Delta G$) must be negative. Given that the degradation of phosgene is non-spontaneous at room temperature, and assuming the reaction is endothermic ($\Delta H > 0$) and leads to an increase in disorder ($\Delta S > 0$), increasing the temperature would increase the $T\Delta S$ term in the Gibbs free energy equation ($\Delta G = \Delta H - T\Delta S$), potentially making $\Delta G$ negative and the reaction spontaneous.

Question 7

Calculate Δ G for the reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) Δ G in kJ/mol for: SO₂( g ) = − 300.2, SO₃( g ) = − 371.1

Accepted Answer

Δ G = 2Δ G_SO2 + Δ G_O2 - 2Δ G_SO3= 2(-300.2) + 0 - 2(-371.1)= -141.8 kJ/mol

Question 8

Calculate Δ S for the reaction: 2 NO₂( g ) → 2 N₂( g ) + O₂( g ) Δ S in J/mol K for: NO₂( g ) = 240.0, N₂( g )= 191.5, O₂( g ) = 205.0

Accepted Answer

The change in entropy (ΔS) for a reaction can be calculated using the formula ΔS = ΣS(products) - ΣS(reactants). For this reaction, ΔS = [2(191.5) + 205.0] - [2(240.0)] = 588.0 - 480.0 = +108 J/K.

Question 9

When magnesium sulfite decomposes, the solid transforms into magnesium oxide and sulfur dioxide. MgSO₃( s ) → MgO( s ) + SO₂( g ) At what temperature will this reaction be spontaneous according to Gibb's Energy? Δ G in kJ/mol for: MgSO₃( s ) = − 1172, MgO( s ) = − 569.6, SO₂( g ) = − 300.2 Δ H in kJ/mol for: MgSO₃( s ) = − 1068, MgO( s ) = − 601.8, SO₂( g ) = − 296.8 Δ S in J/mol K for: MgSO₃( s ) = 121, MgO( s ) = 27, SO₂( g ) = 248.1

Accepted Answer

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

Question 10

Consider the 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 Gibb's Energy? Δ H in kJ/mol for: CO( g ) = − 110.5, CO₂( g ) = − 393.5 Δ S in J/mol K for: CO( g ) = 197.6, CO₂( g ) = 213.6, O₂( g ) = 205.0

Accepted Answer

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

Quiz 10: Entropy and the Second Law of Thermodynamics

Consider the combustion of ethane (C₂H₆) : C₂H₆( g ) + O₂( g ) → CO₂( g ) + H₂O( l ) If Δ G ° (in kJ/mol) for: C₂H₆( g ) = − 32.9, O₂( g ) = 0, CO₂( g ) = − 394.4, and H₂O( l ) = − 237.2; calculate Δ G ° for the reaction.

Calculate Δ S for the reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) Δ S in J/mol K for: SO₂( g ) = 248.1, SO₃( g ) = 256.6, O₂( g ) = 205.0

Calculate Δ S for the reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) Δ S in J/mol K for: CaO( s ) = 40, SO₃( g ) = 256.6, CaSO₄( s ) = 107

Calculate Δ G for the reaction: 2 NO₂( g ) → 2 N₂( g ) + O₂( g ) Δ G in kJ/mol for: NO₂( g ) = 51.30

Calculate Δ G for the reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) Δ G in kJ/mol for: CaO( s ) = − 604.2, SO₃( g ) = − 371.1, CaSO₄( s ) = − 1320

The degradation of phosgene (COCl₂) into CO and Cl₂ happens to be non-spontaneous at room temperature and standard state conditions (273 K, 1 atm) . What change in temperature must occur to make this a spontaneous reaction?

Calculate Δ G for the reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) Δ G in kJ/mol for: SO₂( g ) = − 300.2, SO₃( g ) = − 371.1

Calculate Δ S for the reaction: 2 NO₂( g ) → 2 N₂( g ) + O₂( g ) Δ S in J/mol K for: NO₂( g ) = 240.0, N₂( g ) = 191.5, O₂( g ) = 205.0

Quiz 10: Entropy and the Second Law of Thermodynamics

Consider the combustion of ethane (C2H6) : ​ C2H6( g ) + O2( g ) → CO2( g ) + H2O( l ) ​ If Δ G ° (in kJ/mol) for: C2H6( g ) = − 32.9, O2( g ) = 0, CO2( g ) = − 394.4, and H2O( l ) = − 237.2; calculate Δ G ° for the reaction.

Calculate Δ S for the reaction: 2 SO3( g ) → 2 SO2( g ) + O2( g ) Δ S in J/mol K for: SO2( g ) = 248.1, SO3( g ) = 256.6, O2( g ) = 205.0

Calculate Δ S for the reaction: SO3( g ) + CaO( s ) → CaSO4( s ) Δ S in J/mol K for: CaO( s ) = 40, SO3( g ) = 256.6, CaSO4( s ) = 107

Calculate Δ G for the reaction: 2 NO2( g ) → 2 N2( g ) + O2( g ) Δ G in kJ/mol for: NO2( g ) = 51.30

Calculate Δ G for the reaction: SO3( g ) + CaO( s ) → CaSO4( s ) Δ G in kJ/mol for: CaO( s ) = − 604.2, SO3( g ) = − 371.1, CaSO4( s ) = − 1320

The degradation of phosgene (COCl2) into CO and Cl2 happens to be non-spontaneous at room temperature and standard state conditions (273 K, 1 atm) . What change in temperature must occur to make this a spontaneous reaction?

Calculate Δ G for the reaction: 2 SO3( g ) → 2 SO2( g ) + O2( g ) Δ G in kJ/mol for: SO2( g ) = − 300.2, SO3( g ) = − 371.1

Calculate Δ S for the reaction: 2 NO2( g ) → 2 N2( g ) + O2( g ) Δ S in J/mol K for: NO2( g ) = 240.0, N2( g ) = 191.5, O2( g ) = 205.0

Consider the combustion of ethane (C₂H₆) : C₂H₆( g ) + O₂( g ) → CO₂( g ) + H₂O( l ) If Δ G ° (in kJ/mol) for: C₂H₆( g ) = − 32.9, O₂( g ) = 0, CO₂( g ) = − 394.4, and H₂O( l ) = − 237.2; calculate Δ G ° for the reaction.

Calculate Δ S for the reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) Δ S in J/mol K for: SO₂( g ) = 248.1, SO₃( g ) = 256.6, O₂( g ) = 205.0

Calculate Δ S for the reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) Δ S in J/mol K for: CaO( s ) = 40, SO₃( g ) = 256.6, CaSO₄( s ) = 107

Calculate Δ G for the reaction: 2 NO₂( g ) → 2 N₂( g ) + O₂( g ) Δ G in kJ/mol for: NO₂( g ) = 51.30

Calculate Δ G for the reaction: SO₃( g ) + CaO( s ) → CaSO₄( s ) Δ G in kJ/mol for: CaO( s ) = − 604.2, SO₃( g ) = − 371.1, CaSO₄( s ) = − 1320

The degradation of phosgene (COCl₂) into CO and Cl₂ happens to be non-spontaneous at room temperature and standard state conditions (273 K, 1 atm) . What change in temperature must occur to make this a spontaneous reaction?

Calculate Δ G for the reaction: 2 SO₃( g ) → 2 SO₂( g ) + O₂( g ) Δ G in kJ/mol for: SO₂( g ) = − 300.2, SO₃( g ) = − 371.1

Calculate Δ S for the reaction: 2 NO₂( g ) → 2 N₂( g ) + O₂( g ) Δ S in J/mol K for: NO₂( g ) = 240.0, N₂( g ) = 191.5, O₂( g ) = 205.0