Deck 17: Gibbs Energy and Thermodynamics

Question 1

What is the sign of ΔS_univ for a biological system?

A)positive
B)negative
C)zero
D)It depends on the biological system.

Answer 1

positive

Question 2

Consider a reaction that has a negative Δ_rH and a negative Δ_rS. Which of the following statements is TRUE?

A)This reaction will be spontaneous only at low temperatures.
B)This reaction will be spontaneous at all temperatures.
C)This reaction will be nonspontaneous at all temperatures.
D)This reaction will be nonspontaneous only at low temperatures.
E)This reaction will be spontaneous only at absolute zero (0 Kelvin).

Answer 2

This reaction will be spontaneous only at low temperatures.

Question 3

Consider a reaction that has a positive Δ_rH and a positive Δ_rS. Which of the following statements is TRUE?

A)This reaction will be spontaneous only at low temperatures.
B)This reaction will be spontaneous at all temperatures.
C)This reaction will be nonspontaneous at all temperatures.
D)This reaction will be nonspontaneous at low temperatures.
E)This reaction will be spontaneous only at absolute zero (0 Kelvin).

Answer 3

This reaction will be nonspontaneous at low temperatures.

Question 4

Consider the following reaction at constant pressure. Use the information here to determine the value of ΔS_surr at 398 K. Predict whether or not this reaction will be spontaneous at this temperature. 4NH₃(g)+ 3O₂(g)→ 2N₂(g)+ 6H₂O(g)Δ_rH = -1267 kJ

A)ΔS_surr = +12.67 kJ K^-1 mol^-1, reaction is not spontaneous
B)ΔS_surr = -12.67 kJ K^-1 mol^-1, reaction is spontaneous
C)ΔS_surr = +50.4 kJ K^-1 mol^-1, reaction is not spontaneous
D)ΔS_surr = +3.18 kJ K^-1 mol^-1, reaction is spontaneous
E)ΔS_surr = -3.18 kJ K^-1 mol^-1, reaction is not spontaneous

Question 5

Which of the following statements is TRUE?

A)Entropy is not a state function.
B)Endothermic processes decrease the entropy of the surroundings, at constant T and P.
C)Endothermic processes are never spontaneous.
D)Exothermic processes are always spontaneous.
E)Entropy of the universe is a constant value.

Question 6

Consider a reaction that has a positive Δ_rH and a positive Δ_rS. Which of the following statements is TRUE?

A)This reaction will be spontaneous only at high temperatures.
B)This reaction will be spontaneous at all temperatures.
C)This reaction will be nonspontaneous at all temperatures.
D)This reaction will be nonspontaneous only at high temperatures.
E)This reaction will be spontaneous only at very low temperatures.

Question 7

Which of the following processes shows a decrease in entropy of the system?

A)2NO(g)+ O₂(g)→ 2NO₂(g)
B)COCl₂(g)→ CO(g)+ Cl₂(g)
C)CH₃OH(l)→ CO(g)+ 2H₂(g)
D)NaClO₃(s)→ Na⁺(aq)+ ClO₃^-(aq)
E)H₂(g)+ Cl₂(g)→ 2HCl(g)

Question 8

Consider a reaction that has a negative Δ_rH and a negative Δ_rS. Which of the following statements is TRUE?

A)This reaction will be spontaneous only at high temperatures.
B)This reaction will be spontaneous at all temperatures.
C)This reaction will be nonspontaneous at all temperatures.
D)This reaction will be nonspontaneous only at high temperatures.
E)This reaction will be spontaneous only at absolute zero (0 Kelvin).

Question 9

Which of the following processes have a Δ_rS > 0?

A)2NH₃(g)+ CO₂(g)→ NH₂CONH₂(aq)+ H₂O(l)
B)lithium fluoride forms from Li and F₂
C)2HBr(g)→ H₂(g)+ Br₂(l)
D)sodium chloride dissolves in pure water
E)Ag⁺(aq)+ Cl^-(aq)→ AgCl(s)

Question 10

Consider the following reaction at constant pressure. Use the information here to determine the value of ΔS_surr at 298 K. Predict whether or not this reaction will be spontaneous at this temperature. N₂(g)+ 2O₂(g)→ 2NO₂(g)Δ_rH = +66.4 kJ

A)ΔS_surr = +223 J K^-1 mol^-1, reaction is spontaneous
B)ΔS_surr = -223J K^-1 mol^-1, reaction is not spontaneous
C)ΔS_surr = -66.4 J K^-1 mol^-1, reaction is spontaneous
D)ΔS_surr = +66.4 kJ K^-1 mol^-1, reaction is not spontaneous
E)ΔS_surr = -66.4 J K^-1 mol^-1, reaction is not spontaneous

Question 11

Which of the following statements is TRUE?

A)A spontaneous reaction is a reaction that takes place without any outside intervention.
B)Thermodynamics is a study of reaction rates.
C)A nonspontaneous reaction is a reaction that does not take place under any conditions.
D)Chemical kinetics is a discipline that studies the spontaneity of chemical reactions.
E)Every spontaneous reaction is a very rapid reaction.

Question 12

Consider the following reaction at constant pressure. Use the information here to determine the value of ΔS_surr at 355 K. Predict whether or not this reaction will be spontaneous at this temperature. 2NO(g)+ O₂(g)→ 2NO₂(g)Δ_rH = -114 kJ

A)ΔS_surr = +114 kJ K^-1 mol^-1, reaction is spontaneous
B)ΔS_surr = +114 kJ K^-1 mol^-1, reaction is not spontaneous
C)ΔS_surr = +321 J K^-1 mol^-1, reaction is spontaneous
D)ΔS_surr = -321 J K^-1 mol^-1, reaction is not spontaneous
E)ΔS_surr = +321 J K^-1 mol^-1, reaction is not spontaneous

Question 13

Identify the change in state that does not have an increase in entropy.

A)water freezing
B)water boiling
C)ice melting
D)dry ice subliming
E)water evaporating

Question 14

Consider a reaction that has a positive Δ_rH and a negative Δ_rS. Which of the following statements is TRUE?

A)This reaction will be spontaneous only at high temperatures.
B)This reaction will be spontaneous at all temperatures.
C)This reaction will be nonspontaneous at all temperatures.
D)This reaction will be nonspontaneous only at high temperatures.
E)This reaction will be spontaneous only at absolute zero (0 Kelvin).

Question 15

Which of the following processes have a Δ_rS > 0?

A)CH₃OH(l)→ CH₃OH(s)
B)N₂(g)+ 3H₂(g)→ 2NH₃(g)
C)CH₄(g)+ H₂O (g)→ CO(g)+ 3H₂(g)
D)Na₂CO₃(s)+ H₂O(g)+ CO₂(g)→ 2NaHCO₃(s)
E)H₂O(g)→ H₂O(l)

Question 16

For the following example, what is true about Δ_rH and Δ_rS? 2N₂O(g)→ 2N₂(g)+ O₂(g)

A)a negative Δ_rH and a negative Δ_rS
B)a positive Δ_rH and a negative Δ_rS
C)a negative Δ_rH and a positive Δ_rS
D)a positive Δ_rH and a positive Δ_rS
E)Δ_rH = 0 and a positive Δ_rS

Question 17

Consider a reaction that has a negative Δ_rH and a positive Δ_rS. Which of the following statements is TRUE?

A)This reaction will be spontaneous only at high temperatures.
B)This reaction will be spontaneous at all temperatures.
C)This reaction will be nonspontaneous at all temperatures.
D)This reaction will be nonspontaneous only at high temperatures.
E)This reaction will be spontaneous only at absolute zero (0 Kelvin).

Question 18

In which of the following processes do the molecules become more ordered?

A)water freezing
B)ice melting
C)water evaporating
D)salt dissolving in water
E)dry ice subliming

Question 19

Which of the following relationships is correct at constant T and P?

A)Δ_rG is proportional to -ΔS_univ.
B)Δ_rG > 0 represents a spontaneous process.
C)Δ_rG > 0 represents an increase in kinetic energy.
D)Δ_rG < 0 represents a nonspontaneous process.
E)Δ_rG is not a function of temperature.

Question 20

Which of the following processes have a Δ_rS = 0?

A)water freezes
B)isopropyl alcohol vapour condenses
C)methanol (g, at 555 K)→ methanol (g, at 400 K)
D)carbon dioxide(g)→ carbon dioxide(s)
E)H₂(g)+ F₂(g)→ 2HF(g)

Question 21

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

A)I₂(g)
B)F₂(g)
C)Br₂(l)
D)N₂(g)
E)Cl₂(g)

Question 22

Which one of the following has the highest standard molar entropy, S°, at 25 °C?

A)H₂(g)
B)F₂(g)
C)O₂(g)
D)N₂(g)
E)Cl₂(g)

Question 23

Place the following in order of increasing molar entropy at 298 K. NO CO SO

A)NO < CO < SO
B)SO < CO < NO
C)SO < NO < CO
D)CO < SO < NO
E)CO < NO < SO

Question 24

Above what temperature does the following reaction become nonspontaneous? FeO(s)+ CO(g)→ CO₂(g)+ Fe(s)Δ_rH = -11.0 kJ; Δ_rS = -17.4 J K^-1 mol^-1

A)632 K
B)298 K
C)191 K
D)6.32 × 10³ K
E)0 K

Question 25

Place the following in order of decreasing standard molar entropy. N₂O₄(g)NO(g)NO₂(g)

A)N₂O₄ > NO₂ > NO
B)NO > NO₂ > N₂O₄
C)N₂O₄ > NO > NO₂
D)NO > N₂O₄ > NO₂
E)NO₂ > NO > N₂O₄

Question 26

Place the following in order of decreasing standard molar entropy. NaCl(s)Na₃PO₄(aq)NaCl(aq)

A)NaCl(s)> NaCl(aq)> Na₃PO₄(aq)
B)NaCl(aq)> NaCl(s)> Na₃PO₄(aq)
C)Na₃PO₄(aq)> NaCl(aq)> NaCl(s)
D)NaCl(s)> Na₃PO₄(aq)> NaCl(aq)
E)NaCl(aq)> Na₃PO₄(aq)> NaCl(s)

Question 27

Which of the following statements is TRUE?

A)Entropy is an extensive property.
B)Entropy is not temperature dependent.
C)Exothermic processes decrease the entropy of the surroundings.
D)ΔS_univ is always greater than zero for a nonspontaneous process.
E)Just like enthalpy, entropy has no absolute zero value.

Question 28

Which of the following is TRUE regarding allotropes?

A)Allotropes are different forms of the same element, but they have identical standard molar enthalpies.
B)Allotropes are different forms of the same element and have different standard molar enthalpies.
C)Allotropes are composed of different isotopes of the same element and have different standard molar enthalpies.
D)Allotropes are composed of different isotopes of the same element and identical standard molar enthalpies.
E)Allotropes are different elements with the same structure and have different standard molar enthalpies.

Question 29

Place the following in order of decreasing molar entropy at 298 K. HCl N₂H₄ Ar

A)Ar > N₂H₄ > HCl
B)Ar > HCl > N₂H₄
C)N₂H₄ > Ar > HCl
D)N₂H₄ > HCl > Ar
E)HCl > N₂H₄ > Ar

Question 30

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. C₂H₂(g)+ H₂(g)→ C₂H₄(g)
S°(J J K^-1 mol^-1)200.9 130.7 219.3

A)+112.3 J K^-1 mol^-1
B)+550.9 J K^-1 mol^-1
C)-112.3 J K^-1 mol^-1
D)+337.1 J K^-1 mol^-1
E)-550.9 J K^-1 mol^-1

Question 31

Identify the statement that is TRUE.

A)The entropy of a gas is lower than the entropy of a liquid.
B)Entropy generally decreases with increasing molecular complexity.
C)Free atoms have lower entropy than molecules.
D)Entropy decreases with dissolution.
E)For noble gases, entropy decreases with increase in atomic size.

Question 32

For the following example, what is true about Δ_rH and Δ_rS? H₂O(l)→ H₂O(s)

A)a negative Δ_rH and a negative Δ_rS
B)a positive Δ_rH and a negative Δ_rS
C)a negative Δ_rH and a positive Δ_rS
D)a positive Δ_rH and a positive Δ_rS
E) Δ_rH = 0 and a positive Δ_rS

Question 33

Above what temperature does the following reaction become nonspontaneous? 2H₂S(g)+ 3O₂(g)→ 2SO₂(g)+ 2H₂O(g)Δ_rH = -1036 kJ; Δ_rS = -153.2 J K^-1 mol^-1

A)6.762 × 10³ K
B)158.7 K
C)298 K
D)67.62 K
E)1.587 × 10³ K

Question 34

Place the following in order of increasing molar entropy at 298 K. CO₂ C₃H₈ SO

A)CO₂ < C₃H₈ < SO
B)C₃H₈ < CO₂ < SO
C)SO < CO₂ < C₃H₈
D)C₃H₈ < SO < CO₂
E)CO₂ < SO < C₃H₈

Question 35

Place the following in order of increasing molar entropy at 298 K. Ne Xe He Ar Kr

A)He < Kr < Ne < Ar < Xe
B)Xe < Kr < Ar < Ne < He
C)Ar < He < Ar < Ne < Kr
D)Ar < Ne < Xe < Kr < He
E)He < Ne < Ar < Kr < Xe

Question 36

For the following example, what is true about Δ_rH and Δ_rS? 3O₂(g)→ 2O₃(g)

A)a negative Δ_rH and a negative Δ_rS
B)a positive Δ_rH and a negative Δ_rS
C)a negative Δ_rH and a positive Δ_rS
D)a positive Δ_rH and a positive Δ_rS
E) Δ_rH = 0 and a positive Δ_rS

Question 37

Place the following in order of increasing standard molar entropy. H₂O(l)H₂O(g)H₂O(s)

A)H₂O(g)< H₂O(l)< H₂O(s)
B)H₂O(s)< H₂O(l)< H₂O(g)
C)H₂O(g)< H₂O(s)< H₂O(l)
D)H₂O(l)< H₂O(s)< H₂O(g)
E)H₂O(s)< H₂O(g)< H₂O(l)

Question 38

For the following example, what is true about Δ_rH and Δ_rS? H₂O(l)→ H₂O(g)

A)a negative Δ_rH and a negative Δ_rS
B)a positive Δ_rH and a negative Δ_rS
C)a negative Δ_rH and a positive Δ_rS
D)a positive Δ_rH and a positive Δ_rS
E) Δ_rH = 0 and a positive Δ_rS

Question 39

Below what temperature does the following reaction become nonspontaneous? 2HNO₃(aq)+ NO(g)→ 3NO₂(g)+ H₂O(l)Δ_rH = +136.5 kJ; Δ_rS = +287.5 J K^-1 mol^-1

A)39.2 K
B)151 K
C)475 K
D)4.75 × 10³ K
E)298.17 K

Question 40

Place the following in order of decreasing molar entropy at 298 K. H₂ Cl₂ F₂

A)H₂ > Cl₂ > F₂
B)Cl₂ > H₂ > F₂
C)F₂ > Cl₂ > H₂
D)H₂ > F₂ > Cl₂
E)Cl₂ > F₂ > H₂

Question 41

Calculate Δ_rS° for the following reaction. The S^∘ for each species is shown below the reaction. C₂H₂(g)+ 2H₂(g)→ C₂H₆(g)
S°(J K^-1 mol^-1)200.9 130.7 229.2

A)+303.3 J K^-1 mol^-1
B)+560.8 J K^-1 mol^-1
C)-102.4 J K^-1 mol^-1
D)-233.1 J K^-1 mol^-1
E)229.2 J K^-1 mol^-1

Question 42

Identify the compound with the standard Gibbs energy of formation equal to zero.

A)NaCl(s)
B)N₂(g)
C)NO(g)
D)O₃(g)
E)HCl(g)

Question 43

Given the following equation, N₂O(g)+ NO₂(g)→ 3NO(g)Δ_rG° = -23.0 kJ mol^-1
Calculate Δ_rG° for the following reaction:
3N₂O(g)+ 3NO₂(g)→ 9NO(g)

A)-23.0 kJ mol^-1
B)69.0 kJ mol^-1
C)-69.0 kJ mol^-1
D)-7.67 kJ mol^-1
E)23.0 kJ mol^-1

Question 44

What is the change in Gibbs energy of a process?

A)It is a maximum amount of energy available to do work.
B)It is energy that is lost to the surroundings.
C)It is energy that is used to break chemical bonds.
D)It is energy that is converted to heat.
E)It is the total energy of a process.

Question 45

Estimate Δ_rG° for the following reaction at 387 K. HCN(g)+ 2H₂(g)→ CH₃NH₂(g)Δ_rH°= -158.0 kJ mol^-1; Δ_rS°= -219.9 J K^-1 mol^-1

A)+243 kJ mol^-1
B)-72.9 kJ mol^-1
C)+84.9 kJ mol^-1
D)-92.5 kJ mol^-1
E)-188 kJ mol^-1

Question 46

Determine Δ_rG° at 298 K using the following information: CaCO₃(s)→ CaO(s)+ CO₂(g)Δ_rH°= +179.2 kJ mol^-1; Δ_rS°= +160.2 J K^-1 mol^-1

A)-607.0 kJ mol^-1
B)+112 .0 kJ mol^-1
C)-89.3 kJ mol^-1
D)+131.4 kJ mol^-1
E)+228.1 kJ mol^-1

Question 47

Given the following equation, N₂O(g)+ NO₂(g)→ 3NO(g)Δ_rG° = -23.0 kJ mol^-1
Calculate Δ_rG^o for the following reaction:
3NO(g)→ N₂O(g)+ NO₂(g)

A)-23.0 kJ mol^-1
B)69.0 kJ mol^-1
C)-69.0 kJ mol^-1
D)-7.67 kJ mol^-1
E)23.0 kJ mol^-1

Question 48

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. N₂H₄(l)+ H₂(g)→ 2NH₃(g)
S° (J K^-1 mol^-1)121.2 130.7 192.8

A)+133.7 J K^-1 mol^-1
B)-59.1 J K^-1 mol^-1
C)+118.2 J K^-1 mol^-1
D)-202.3 J K^-1 mol^-1
E)+178.9 J K^-1 mol^-1

Question 49

Calculate Δ_rS° for the following reaction. The S° for each species is shown below the reaction. 4NH₃(g)+ 5O₂(g)→ 4NO(g)+ 6H₂O(g)
S°(J K^-1 mol^-1)192.8 205.2 210.8 188.8

A)+287.4 J K^-1 mol^-1
B)-401.2 J K^-1 mol^-1
C)+160.0 J K^-1 mol^-1
D)-336.6 J K^-1 mol^-1
E)+178.8 J K^-1 mol^-1

Question 50

Calculate Δ_rG° at 298 K using the following information: 2H₂S(g)+ 3O₂(g)→ 2SO₂(g)+ 2H₂O(g)Δ_rG° = ?
Δ_fG°(kJ mol^-1)-33.4 -300.1 -228.6

A)+112.4 kJ mol^-1
B)-495.3 kJ mol^-1
C)-528.7 kJ mol^-1
D)+66.8 kJ mol^-1
E)-990.6 kJ mol^-1

Question 51

Estimate Δ_rG° for the following reaction at 449.0 K. CH₂O(g)+ 2H₂(g)→ CH₄(g)+ H₂O(g)Δ_rH°= -94.9 kJ mol^-1; Δ_rS°= -224.2 J K^-1 mol^-1

A)+5.8 kJ mol^-1
B)+12.9 kJ mol^-1
C)-101 kJ mol^-1
D)+2.4 kJ mol^-1
E)-4.2 kJ mol^-1

Question 52

Determine Δ_rG° at 298 K using the following information: H₂(g)+ CO(g)→ CH₂O(g) Δ_rH°= +1.9 kJ mol^-1; Δ_rS°= -109.6 J K^-1 mol^-1

A)+57.7 kJ mol^-1
B)-30.8 kJ mol^-1
C)+34.6 kJ mol^-1
D)-41.5 kJ mol^-1
E)+17.3 kJ mol^-1

Question 53

What is the name of the reaction that does NOT achieve the theoretical limits with respect to the change in Gibbs energy in thermodynamics?

A)reversible reaction
B)forward reaction
C)reverse reaction
D)equilibrium reaction
E)irreversible reaction

Question 54

What is the name of the reaction that achieves the theoretical limits with respect to the change in Gibbs energy in thermodynamics?

A)reversible reaction
B)forward reaction
C)reverse reaction
D)equilibrium reaction
E)irreversible reaction

Question 55

Given the following equation, N₂O(g)+ NO₂(g)→ 3 NO(g)Δ_rG° = -23.0 kJ mol^-1
Calculate Δ_rG° for the following reaction:
9NO(g)→ 3N₂O(g)+ 3NO₂(g)

A)-23.0 kJ mol^-1
B)69.0 kJ mol^-1
C)-69.0 kJ mol^-1
D)-7.67 kJ mol^-1
E)23.0 kJ mol^-1

Question 56

Estimate Δ_rG° for the following reaction at 775 K. 2Hg(g)+ O₂(g)→ 2HgO(s) Δ_rH°= -304.2 kJ mol^-1; Δ_rS°= -414.2 J K^-1 mol^-1

A)-625 kJ mol^-1
B)-181 kJ mol^-1
C)+17 kJ mol^-1
D)+321 kJ mol^-1
E)-110 kJ mol^-1

Question 57

Identify the compound with the lowest standard Gibbs energy of formation.

A)NaCl(s)
B)N₂(g)
C)NO(g)
D)O₃(g)
E)Cl_2(g)

Question 58

Identify the compound with the highest standard Gibbs energy of formation.

A)NaCl(s)
B)N₂(g)
C)NO(g)
D)O₃(g)
E)Cl₂(g)

Question 59

Calculate ΔρS° for the following reaction. The S° for each species is shown below the reaction. P₄(g)+ 10Cl₂(g)→ 4PCl₅(g)
S°(J K^-1 mol^-1)280.0 223.1 364.6

A)-138.5 J K^-1 mol^-1
B)-1052.6 J K^-1 mol^-1
C)+171.3 J K^-1 mol^-1
D)-583.6 J K^-1 mol^-1
E)+2334.6 J K^-1 mol^-1

Question 60

Determine Δ_rG° at 298 K using the following information: FeO(s)+ CO(g)→ Fe(s)+ CO₂(g)Δ_rH°= -11.0 kJ mol^-1; Δ_rS°= -17.4 J K^-1 mol^-1

A)+191.0 kJ mol^-1
B)-5.8 kJ mol^-1
C)+1.6 kJ mol^-1
D)-6.4 kJ mol^-1
E)+89.5 kJ mol^-1

Question 61

Which of the following is true for ?_rG?

A)If??_rG > 0, the reaction is spontaneous in the forward direction.
B)If Q = 1, then $\Delta$ _rG > ?_rG.
C)If $\Delta$ _rG ? 0, the reaction is spontaneous in both the reverse and forward directions.
D)If $\Delta$ _rG < 0, the reaction is spontaneous in the reverse direction.
E)Under equilibrium conditions, $\Delta$ _rG = 0.

Question 62

Calculate Δ_rG° at 298 K using the following information: 2H₂S(g)+ 3O₂(g)→ 2SO₂(g)+ 2H₂O(g)Δ_rG° = ?
Δ_fH° (kJ mol^-1)-20.6 -296.8 -241.8
S°(J K^-1 mol^-1)205.8 205.2 248.2 188.8

A)-990.3 kJ mol^-1
B)+108.2 kJ mol^-1
C)-466.1 kJ mol^-1
D)+676.2 kJ mol^-1
E)-147.1 kJ mol^-1

Question 63

Calculate Δ_rG° at 298 K using the following information: 4HNO₃(g)+ 5N₂H₄(l)→ 7N₂(g)+ 12H₂O(l)Δ_rG° = ?
Δ_fG° (kJ mol^-1)-73.5 149.3 -237.1

A)-3.2977 × 10³ kJ mol^-1
B)-312.9 kJ mol^-1
C)+2.845 × 10³ kJ mol^-1
D)+110.7 kJ mol^-1
E)-954.7 kJ mol^-1

Question 64

Use Hess's law to calculate Δ_rG° using the following information: NO(g)+ O(g)→ NO₂(g)Δ_rG° = ?
2O₃(g)→ 3O₂(g)Δ_rG° = +489.6 kJ mol^-1
O₂(g)→ 2O(g)Δ_rG° = +463.4 kJ mol^-1
NO(g)+ O₃(g)→ NO₂(g)+ O₂(g)Δ_rG° = - 199.5 kJ mol^-1

A)+753.5 kJ mol^-1
B)+277.0 kJ mol^-1
C)-676.0 kJ mol^-1
D)-1152.5 kJ mol^-1
E)-225.7 kJ mol^-1

Question 65

Calculate Δ_rG at 298 K under the conditions shown below for the following reaction: CaCO₃(s)→ CaO(s)+ CO₂(g)Δ_rG° =+131.1 kJ mol^-1
P(CO₂)= 0.033 atm

A)-49.3 kJ mol^-1
B)-8.32 kJ mol^-1
C)+122.6 kJ mol^-1
D)+39.7 kJ mol^-1
E)+43.3 kJ mol^-1

Question 66

Calculate Δ_rG° at 298 K using the following information: 2HNO₃(aq)+ NO(g)→ 3NO₂(g)+ H₂O(l)Δ_rG° = ?
Δ_fG° (kJ mol^-1)-110.9 87.6 51.3 -237.1

A)-162.5 kJ mol^-1
B)+51.0 kJ mol^-1
C)-54.5 kJ mol^-1
D)+171.1 kJ mol^-1
E)-87.6 kJ mol^-1

Question 67

Use Hess's law to calculate Δ_rG° using the following information: CO(g)→ C(s)+ 1/2 O₂(g) Δ_rG° = ?
CO₂(g)→ C(s)+ O₂(g)Δ_rG° = +394.4 kJ mol^-1
CO(g)+ 1/2 O₂(g)→ CO₂(g)Δ_rG° = -257.2 kJ mol^-1

A)-60.0 kJ mol^-1
B)+651.6 kJ mol^-1
C)-265.8 kJ mol^-1
D)+137.2 kJ mol^-1
E)+523.0 kJ mol^-1

Question 68

Calculate Δ_rG at 298 K under the conditions shown below for the following reaction: 2Hg(g)+ O₂(g)→ 2HgO(s) ΔG° = -180.8 kJ mol^-1
P(Hg)= 0.025 atm, P(O₂)= 0.037 atm

A)+207 kJ mol^-1
B)-154.4 kJ mol^-1
C)-26.5 kJ mol^-1
D)-164 kJ mol^-1
E)+60.7 kJ mol^-1

Question 69

Choose the statement below that is TRUE.

A)If K > 1, Δ_rG for forward reaction is positive.
B)If K < 1, Δ_rG for forward reaction is negative.
C)If K > 1, Δ_rG for reverse reaction is negative.
D)Δ_rG = 0 at equilibrium.
E)If K < 1, Δ_rG for reverse reaction is positive.

Question 70

Which of the following is TRUE if ln K is positive?

A)Δ_rG° is positive and the reaction is spontaneous in the forward direction.
B)Δ_rG° is negative and the reaction is spontaneous in the forward direction.
C)Δ_rG° is negative and the reaction is spontaneous in the reverse direction.
D)Δ_rG° is positive and the reaction is spontaneous in the reverse direction.
E)Δ_rG° is zero and the reaction is at equilibrium.

Question 71

Calculate Δ_rG at 298 K under the conditions shown below for the following reaction: Fe₂O₃(s)+ 3CO(g)→ 2Fe(s)+ 3CO₂(g)ΔG° = -28.0 kJ mol^-1
P(CO)= 1.4 atm, P(CO₂)= 2.1 atm

A)+31.0 kJ mol^-1
B)+2.99 kJ mol^-1
C)-30.7 kJ mol^-1
D)+17.5 kJ mol^-1
E)-25.0 kJ mol^-1

Question 72

Calculate Δ_rG at 298 K under the conditions shown below for the following reaction: 3O₂(g)→ 2O₃(g)Δ_rG° = +326 kJ
P(O₂)= 0.41 atm, P(O₃)= 5.2 atm

A)+341 kJ
B)+17.8 kJ
C)+332 kJ
D)-47.4 kJ
E)-109 kJ

Question 73

Use the free energies of formation given below to calculate the equilibrium constant (K)for the following reaction at 298 K: 2HNO₃(aq)+ NO(g)→ 3 NO₂(g)+ H₂O(l)K = ?
Δ_fG° (kJ mol^-1)-110.9 87.6 51.3 -237.1

A)8.71 × 10⁸
B)0.980
C)1.15 × 10^-9
D)1.02
E)5.11 × 10^-4

Question 74

Which of the following is TRUE if ln K is negative?

A)Δ_rG° is positive and the reaction is spontaneous in the forward direction.
B)Δ_rG° is negative and the reaction is spontaneous in the forward direction.
C)Δ_rG° is negative and the reaction is spontaneous in the reverse direction.
D)Δ_rG° is positive and the reaction is spontaneous in the reverse direction.
E)Δ_rG° is zero and the reaction is at equilibrium.

Question 75

Use Hess's law to calculate Δ_rG° using the following information: ClO(g)+ O₃(g)→ Cl(g)+ 2O₂(g)Δ_rG° = ?
2O₃(g)→ 3O₂(g)Δ_rG° = +489.6 kJ mol^-1
Cl(g)+ O₃(g)→ ClO(g)+ O₂(g)Δ_rG° = -34.5 kJ mol^-1

A)-472.4 kJ mol^-1
B)-210.3 kJ mol^-1
C)+455.1 kJ mol^-1
D)+262.1 kJ mol^-1
E)+524.1 kJ mol^-1

Question 76

Calculate Δ_rG at 298 K under the conditions shown below for the following reaction: SO₃(g)+ H₂O(g)→ H₂SO₄(l)Δ_rG°= -90.5 kJ mol^-1
P(SO₃)= 0.20 atm, P(H₂O)= 0.88 atm

A)+15.9 kJ mol^-1
B)-90.5 kJ mol^-1
C)+51.4 kJ mol^-1
D)-86.2 kJ mol^-1
E)-30.4 kJ mol^-1

Question 77

Which of the following is TRUE if ln K is zero?

A)Δ_rG° is positive and the reaction is spontaneous in the forward direction.
B)Δ_rG° is negative and the reaction is spontaneous in the forward direction.
C)Δ_rG° is negative and the reaction is spontaneous in the reverse direction.
D)Δ_rG° is positive and the reaction is spontaneous in the reverse direction.
E)Δ_rG° is zero and the reaction is at equilibrium.

Question 78

Calculate ?_rG° at 298 K using the following information: 2HNO₃(aq)+ NO(g)? 3NO₂(g)+ H₂O(l)?_rG° = ?
?_fH° (kJ mol^-1)-207.0 91.3 33.2 -285.8
S°(J K^-1 mol^-1)146.0 210.8 240.1 70.0

A)-151 kJ mol^-1
B)-85.5 kJ mol^-1
C)+50.8 kJ mol^-1
D)+222 kJ mol^-1
E)-186 kJ mol^-1

Question 79

Calculate Δ_rG° at 298 K using the following information: 4HNO₃(g)+ 5N₂H₄(l)→ 7N₂(g)+ 12H₂O(l)Δ_rG° = ?
Δ_fH° (kJ mol^-1)-133.9 50.6 -285.8
S°(J K^-1 mol^-1)266.9 121.2 191.6 70.0

A)+4.90 × 10³ kJ mol^-1
B)+3.90 × 10³ kJ mol^-1
C)-2.04 × 10³ kJ mol^-1
D)-3.15 × 10³ kJ mol^-1
E)-3.30 × 10³ kJ mol^-1

Question 80

Which of the following reactions will have the largest equilibrium constant (K)at 298 K?

A)CaCO₃(s)→ CaO(s)+ CO₂(g)Δ_rG° =+131.1 kJ mol^-1
B)2 Hg(g)+ O₂(g)→ 2HgO(s) Δ_rG° = -180.8 kJ mol^-1
C)3O₂(g)→ 2O₃(g) Δ_rG° = +326 kJ mol^-1
D)Fe₂O₃(s)+ 3CO(g)→ 2Fe(s)+ 3CO₂(g)Δ_rG° = -28.0 kJ mol^-1