Deck 19: Free Energy and Thermodynamics

Question 1

________ is a thermodynamic function that increases with the number of energetically equivalent ways to arrange components of a system to achieve a particular state.

A) Heat of reaction
B) Free energy
C) Entropy
D) Enthalpy
E) Molar equivalence

Answer 1

Entropy

Question 2

Which of the following statements is TRUE?

A) There is a "heat tax" for every energy transaction.
B) A spontaneous reaction is always a fast reaction.
C) The entropy of a system always decreases for a spontaneous process.
D) Perpetual motion machines are a possibility in the near future.
E) None of the above are true.

Answer 2

There is a "heat tax" for every energy transaction.

Question 3

For a given compound,list the decreasing order of entropy for a liquid,solid,and gas.

A) solid > gas > liquid
B) liquid > solid > gas
C) gas > liquid > solid
D) gas > solid > liquid
E) solid > liquid > gas

Answer 3

gas > liquid > solid

Question 4

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 5

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 6

At what temperature does a perfect crystalline solid have S=0?

A) 0 K
B) 0°C
C) 100 °C
D) 273 K
E) It is not possible for a substance to have S=0.

Question 7

Identify the statement that is FALSE.

A) The entropy of a gas is greater than the entropy of a liquid.
B) Entropy generally increases with increasing molecular complexity.
C) Free atoms have greater entropy than molecules.
D) Entropy increases with dissolution.
E) For noble gasses, entropy increases with size.

Question 8

Identify the process that is spontaneous

A) rusting of iron
B) electrolysis
C) photosynthesis
D) water flowing uphill
E) burning gasoline

Question 9

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 10

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 11

Place the following in order of increasing 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 12

The ________ Law of Thermodynamics states the energy is conserved in chemical processes.

A) Zero
B) First
C) Second
D) Third
E) Fourth

Question 13

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 14

Which of the following processes have a ΔS > 0?

A) CH₃OH(l) → CH₃OH(s)
B) N₂(g) + 3 H₂(g) → 2 NH₃(g)
C) CH₄(g) + H₂O(g) → CO(g) + 3 H₂(g)
D) Na₂CO₃(s) + H₂O(g) + CO₂(g) → 2 NaHCO₃(s)
E) All of the above processes have a DS > 0.

Question 15

The ________ Law of Thermodynamics states that for any spontaneous reaction,the entropy of the universe increases.

A) Zero
B) First
C) Second
D) Third
E) Fourth

Question 16

Place the following in order of increasing entropy at 298 K. C₂H₆(g),Pb(s),Mg(s),CH₄(g)

A) Mg, Pb, C₂H₆, CH₄
B) C₂H₆, CH₄, Pb, Mg
C) Pb, Mg, CH₄, C₂H₆
D) Mg, Pb, CH₄, C₂H₆
E) Pb, Mg, C₂H₆, CH₄

Question 17

Which of the following processes have a ΔS < 0?

A) The melting of a cube of ice
B) Dissolving of salt into water
C) Water boiling on the stovetop
D) Dry ice sublimating into carbon dioxide gas
E) Condensation of water vapor into rain drops

Question 18

All of the following are examples of a spontaneous process EXCEPT

A) a nail left outside in the rain starts to rust.
B) a reaction speeding up upon the addition of a catalyst.
C) a book falls off a desk and drops on the floor.
D) a boulder slides down the side of a mountain.
E) water freezing when the temperature drops below 0°C.

Question 19

According to the Second Law of Thermodynamics,in order for a reaction to be spontaneous which value must increase?

A) ∆S_surr
B) ∆S_sys
C) ∆S_universe
D) ∆H_rxn
E) ∆T

Question 20

The ________ Law of Thermodynamics states the entropy of a perfect crystal at absolute zero is zero.

A) Zero
B) First
C) Second
D) Third
E) Fourth

Question 21

Consider a reaction that has a positive ΔH and a negative ΔS.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) It is not possible to determine without more information.

Question 22

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

A) +287.4 J/K
B) -401.2 J/K
C) +160.0 J/K
D) -336.6 J/K
E) +178.8 J/K

Question 23

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

A) -138.5 J/K
B) -1052.6 J/K
C) +171.3 J/K
D) -583.6 J/K
E) +2334.6 J/K

Question 24

For the following example,identify the following. H₂O(l)→ H₂O(g)

A) a negative ΔH and a negative ΔS
B) a positive ΔH and a negative ΔS
C) a negative ΔH and a positive ΔS
D) a positive ΔH and a positive ΔS
E) It is not possible to determine without more information.

Question 25

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

A) +303.3 J/K
B) +560.8 J/K
C) -102.4 J/K
D) -233.1 J/K
E) 229.2 J/K

Question 26

Consider a reaction that has a positive ΔH and a positive ΔS.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) It is not possible to determine without more information.

Question 27

Above what temperature does the following reaction become nonspontaneous?
2 H₂S(g)+ 3 O₂(g)→ 2 SO₂(g)+ 2 H₂O(g)ΔH = -1036 kJ; ΔS = -153.2 J/K

A) 6.762 × 10³ K
B) 158.7 K
C) 298 K
D) This reaction is nonspontaneous at all temperatures.
E) This reaction is spontaneous at all temperatures.

Question 28

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) None of the above are true.

Question 29

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

A) +112.3 J/K
B) +550.9 J/K
C) -112.3 J/K
D) +337.1 J/K
E) -550.9 J/K

Question 30

For the following example,identify the following. H₂O(l)→ H₂O(s)

A) a negative ΔH and a negative ΔS
B) a positive ΔH and a negative ΔS
C) a negative ΔH and a positive ΔS
D) a positive ΔH and a positive ΔS
E) It is not possible to determine without more information.

Question 31

Consider a reaction that has a negative ΔH and a negative ΔS.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) It is not possible to determine without more information.

Question 32

Consider a reaction that has a negative ΔH and a positive ΔS.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) It is not possible to determine without more information.

Question 33

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

A) +133.7 J/K
B) -59.1 J/K
C) +118.2 J/K
D) -202.3 J/K
E) +178.9 J/K

Question 34

Above what temperature does the following reaction become nonspontaneous?
FeO(s)+ CO(g)→ CO₂(g)+ Fe(s)ΔH = -11.0 kJ; ΔS = -17.4 J/K

A) 632 K
B) 298 K
C) 191 K
D) This reaction is nonspontaneous at all temperatures.
E) This reaction is spontaneous at all temperatures.

Question 35

What is the sign of ΔS_univ for a biological system?

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

Question 36

Consider a reaction that has a negative ΔH and a negative ΔS.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) It is not possible to determine without more information.

Question 37

Which of the following statements is TRUE?

A) Entropy is an extensive property.
B) Entropy is temperature independent.
C) Exothermic processes decrease the entropy of the surroundings.
D) ΔS_universe is always greater than zero for a nonspontaneous process.
E) None of the above are true.

Question 38

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

A) ΔG is proportional to -ΔS_univ.
B) ΔG > 0 represents a spontaneous process.
C) ΔG > 0 represents an increase in kinetic energy.
D) ΔG < 0 represents a nonspontaneous process.
E) All of the above are correct.

Question 39

Calculate ∆S°_rxn for the following reaction.The S° for each species is shown below the reaction. 2NO(g)+ 2 H₂(g)→ N₂(g)+ 2 H₂O(l)
S°(J/mol^∙K)210.8 130.7 191.6 69.9

A) +1183.8 J/K
B) -351.6 J/K
C) -469.3 J/K
D) +503.9 J/K
E) +111.4 J/K

Question 40

Consider a reaction that has a positive ΔH and a positive ΔS.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) It is not possible to determine without more information.

Question 41

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

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

Question 42

Calculate ΔG_rxn at 298 K under the conditions shown below for the following reaction. CaCO₃(s)→ CaO(s)+ CO₂(g)ΔG° =+131.1 kJ
P(CO₂)= 0.033 atm

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

Question 43

Calculate the ΔG°_rxn using the following information. 4 HNO₃(g)+ 5 N₂H₄(l)→ 7 N₂(g)+ 12 H₂O(l)ΔG°_rxn = ?
ΔG°_f (kJ/mol)-73.5 149.3 -237.1

A) -3.298 × 10³ kJ
B) -312.9 kJ
C) +2.845 × 10³ kJ
D) +110.7 kJ
E) -954.7 kJ

Question 44

Calculate ΔG_rxn at 298 K under the conditions shown below for the following reaction. 3 O₂(g)→ 2 O₃(g)ΔG° = +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 45

What can change the direction of a reversible reaction?

A) change in temperature
B) change in pressure
C) change in volume
D) A, B, and C
E) none of the above

Question 46

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

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

Question 47

Use Hess's law to calculate ΔG°_rxn using the following information. NO(g)+ O(g)→ NO₂(g)ΔG°_rxn = ?
2 O₃(g)→ 3 O₂(g)ΔG°_rxn = +489.6 kJ
O₂(g)→ 2 O(g)ΔG°_rxn = +463.4 kJ
NO(g)+ O₃(g)→ NO₂(g)+ O₂(g)ΔG°_rxn = - 199.5 kJ

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

Question 48

Choose the statement below that is TRUE.

A) K > 1, ΔG°_rxn is positive.
B) K < 1, ΔG°_rxn is negative.
C) ΔG°_rxn = 0 at equilibrium.
D) ΔG_rxn = 0 at equilibrium.
E) None of the above statements are true.

Question 49

Give the name of the reaction that does not achieve the theoretical limits with respect to free energy in thermodynamics.

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

Question 50

Use Hess's law to calculate ΔG°_rxn using the following information. ClO(g)+ O₃(g)→ Cl(g)+ 2 O₂(g)ΔG°_rxn = ?
2 O₃(g)→ 3 O₂(g)ΔG°_rxn = +489.6 kJ
Cl(g)+ O₃(g)→ ClO(g)+ O₂(g)ΔG°_rxn = -34.5 kJ

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

Question 51

Which of the following is NOT true for ΔG_rxn?

A) If ΔG°_rxn > 0, the reaction is spontaneous in the forward direction.
B) If Q = 1, then ΔG_rxn = ΔG°_rxn.
C) ΔG°_rxn = K
D) If ΔG°_rxn > 0, the reaction is spontaneous in the reverse direction.
E) Under equilibrium conditions, ΔG_rxn = 0.

Question 52

Below what temperature does the following reaction become nonspontaneous?
2 HNO₃(aq)+ NO(g)→ 3 NO₂(g)+ H₂O(l)ΔH = +136.5 kJ; ΔS = +287.5 J/K

A) 39.2 K
B) 151 K
C) 475 K
D) This reaction is nonspontaneous at all temperatures.
E) This reaction is spontaneous at all temperatures.

Question 53

Determine ΔG°_rxn using the following information. 2 H₂S(g)+ 3 O₂(g)→ 2 H₂O(l)+ 2 SO₂(g)ΔH°= +1.12 kJ; ΔS°= -390.7 J/K

A) -118 kJ
B) -348 kJ
C) +28.4 kJ
D) -58.3 kJ
E) +440 kJ

Question 54

Determine ΔG°_rxn using the following information. H₂(g)+ CO(g)→ CH₂O(g)ΔH°= +1.9 kJ; ΔS°= -109.6 J/K

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

Question 55

Calculate the ΔG°_rxn using the following information. 2 H₂S(g)+ 3 O₂(g)→ 2 SO₂(g)+ 2 H₂O(g)ΔG°_rxn = ?
ΔH°_f (kJ/mol)-20.6 -296.8 -241.8
S°(J/mol^∙K)205.8 205.2 248.2 188.8

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

Question 56

Calculate the ΔG°_rxn using the following information. 2 HNO₃(aq)+ NO(g)→ 3 NO₂(g)+ H₂O(l)ΔG°_rxn = ?
ΔG°_f (kJ/mol)-110.9 87.6 51.3 -237.1

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

Question 57

Give the name of the reaction that achieves the theoretical limits with respect to free energy in thermodynamics.

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

Question 58

Calculate the ΔG°_rxn using the following information. 2 HNO₃(aq)+ NO(g)→ 3 NO₂(g)+ H₂O(l)ΔG°_rxn = ?
ΔH°_f (kJ/mol)-207.0 91.3 33.2 -285.8
S°(J/mol^∙K 146.0 210.8 240.1 70.0

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

Question 59

Given the following equation, N₂O(g)+ NO₂(g)→ 3 NO(g)ΔG°_rxn = -23.0 kJ
Calculate ΔG°_rxn for the following reaction.
3 NO(g)→ N₂O(g)+ NO₂(g)

A) -23.0 kJ
B) 69.0 kJ
C) -69.0 kJ
D) -7.67 kJ
E) 23.0 kJ

Question 60

Calculate the ΔG°_rxn using the following information. 4 HNO₃(g)+ 5 N₂H₄(l)→ 7 N₂(g)+ 12 H₂O(l)ΔG°_rxn = ?
ΔH°_f (kJ/mol)-133.9 50.6 -285.8
S°(J/mol^∙K)266.9 121.2 191.6 70.0

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

Question 61

What is TRUE if ln K is positive?

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

Question 62

Determine the equilibrium constant for the following reaction at 298 K. N₂(g)+ O₂(g)→ 2 NO(g)ΔG° = 173.3 kJ

A) 5.31 × 10^-15
B) 4.19 × 10^-31
C) 6.03 × 10^-6
D) 1.32 × 10^-22
E) 2.42× 10^-11

Question 63

Determine the equilibrium constant for the following reaction at 298 K. Cl(g)+ O₃(g)→ ClO(g)+ O₂(g)ΔG° = - 34.5 kJ

A) 5.66 × 10⁵
B) 0.986
C) 8.96 × 10^-7
D) 4.98 × 10^-4
E) 1.12 × 10⁶

Question 64

Determine the equilibrium constant for the following reaction at 655 K. HCN(g)+ 2 H₂(g)→ CH₃NH₂(g)ΔH° = -158 kJ; ΔS°= -219.9 J/K

A) 3.99 × 10¹²
B) 13.0
C) 2.51 × 10^-13
D) 3.26 × 10^-12
E) 3.07 × 10¹¹

Question 65

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

A) CaCO₃(s) → CaO(s) + CO₂(g) ΔG° =+131.1 kJ
B) 2 Hg(g) + O₂(g) → 2 HgO(s) ΔG° = -180.8 kJ
C) 3 O₂(g) → 2 O₃(g) ΔG° = +326 kJ
D) Fe₂O₃(s) + 3 CO(g) → 2 Fe(s) + 3 CO₂(g) ΔG° = -28.0 kJ
E) It is not possible to determine without more information.

Question 66

Below what temperature does the following reaction become nonspontaneous?
I₂(s)+ Cl₂(g)→ 2 ICl(s)ΔH = +36.0 kJ; ΔS = +158.8 J/K

A) 128 K
B) 227 K
C) 313 K
D) This reaction is nonspontaneous at all temperatures.
E) This reaction is spontaneous at all temperatures.

Question 67

Determine the equilibrium constant for the following reaction at 498 K. 2 Hg(g)+ O₂(g)→ 2 HgO(s)ΔH° = -304.2 kJ; ΔS° = -414.2 J/K

A) 1.87 × 10¹⁰
B) 8.10 × 10³¹
C) 2.31 × 10^-22
D) 5.34 × 10^-11
E) 4.33 × 10²¹

Question 68

A reaction has PCl₃ as one of the products.Determine the equilibrium constant for the reaction at 550 K knowing that ΔH° = -210 kJ and ΔS° = -410.1 J/K

A) 6.32 × 10³
B) 3.02 × 10^-2
C) 6.63 × 10^-6
D) 2.41 × 10²
E) 9.43 × 10-9

Question 69

Above what temperature does the following reaction become nonspontaneous?
N₂(s)+ 3 H₂(g)→ 2 NH₃(g)ΔH = -92.22 kJ; ΔS = -198.75 J/K

A) 186 K
B) 326 K
C) 464 K
D) This reaction is nonspontaneous at all temperatures.
E) This reaction is spontaneous at all temperatures.

Question 70

What is TRUE if ln K is negative?

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

Question 71

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

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

Question 72

What is TRUE if ln K is 1?

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

Question 73

Which of the following processes have a ΔS < 0?

A) water freezes
B) isopropyl alcohol condenses
C) ethanol (g, at 555 K) → ethanol (g, at 400 K)
D) carbon dioxide(g) → carbon dioxide(s)
E) All of the above processes have a ΔS < 0.

Question 74

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

A) CaCO₃(s) → CaO(s) + CO₂(g) ΔG° =+131.1 kJ
B) 2 Hg(g) + O₂(g) → 2 HgO(s) ΔG° = -180.8 kJ
C) 3 O₂(g) → 2 O₃(g) ΔG° = +326 kJ
D) Fe₂O₃(s) + 3 CO(g) → 2 Fe(s) + 3 CO₂(g) ΔG° = -28.0 kJ
E) It is not possible to determine without more information.

Question 75

Determine the equilibrium constant for the following reaction at 549 K. CH₂O(g)+ 2 H₂(g)→ CH₄(g)+ H₂O(g)ΔH° = -94.9 kJ; ΔS°= -224.2 J/K

A) 481
B) 1.07 × 10⁹
C) 2.08 × 10^-3
D) 9.35 × 10^-10
E) 1.94 × 10^-12

Question 76

Use the free energies of formation given below to calculate the equilibrium constant (K)for the following reaction at 298 K. 2 HNO₃(aq)+ NO(g)→ 3 NO₂(g)+ H₂O(l)K = ?
ΔG°_f (kJ/mol)-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 77

In which of the following processes does the substance become more orderly?

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

Question 78

Determine the equilibrium constant for the following reaction at 655 K. HCN(g)+ 2 H₂(g)→ CH₃NH₂(g)ΔH° = -158 kJ; ΔS°= -219.9 J/K

A) 3.99 × 10¹²
B) 13.0
C) 2.51 × 10^-13
D) 3.26 × 10^-12
E) 3.07 × 10¹¹

Question 79

Which of the following processes have a ΔS > 0?

A) 2 NH₃(g) + CO₂(g) → NH₂CONH₂(aq) + H₂O(l)
B) lithium fluoride forms from its elements
C) 2 HI(g) → H₂(g) + I₂(l)
D) lithium chloride dissolves in pure water
E) All of the above processes have a DS > 0.

Question 80

Determine the equilibrium constant for the following reaction at 298 K. SO₃(g)+ H₂O(g)→ H₂SO₄(l)ΔG° = -90.5 kJ

A) 1.37 × 10^-16
B) 4.78 × 10¹¹
C) 9.11 × 10^-8
D) 7.31 × 10¹⁵
E) 0.964