Question 1

Why can't we say that a spontaneous reaction is a fast reaction?

Accepted Answer

Spontaneity is a thermodynamic

Question 2

For a given reaction,ΔH = -27.7 kJ/mol and ΔS = -76.6 J/Kmol.The reaction will have ΔG = 0 at ________ K.Assume that ΔH and ΔS do not vary with temperature.

Accepted Answer

A)  362 
B)  2765 
C)  298 
D)  2.77 
E)  0.362 
A)  362 
B)  2765 
C)  298 
D)  2.77 
E)  0.362

Question 3

Estimate ΔG°rxn for the following reaction at 417 K. HCN(g)+ 2 H2(g)→ CH3NH2(g)ΔH°= -158.0 kJ; ΔS°= -219.9 J/K

Accepted Answer

A)  +61.9 kJ 
B)  - 66.3 kJ 
C)  + 66.3 kJ 
D)  - 250 kJ 
E)  + 250 kJ 
A)  +61.9 kJ 
B)  - 66.3 kJ 
C)  + 66.3 kJ 
D)  - 250 kJ 
E)  + 250 kJ

Question 4

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

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

Given the following equation, N2O(g)+ NO2(g)→ 3 NO(g)ΔG°rxn = -23.0 kJ
Calculate ΔG°rxn for the following reaction.
2 N2O(g)+ 2 NO2(g)→ 6 NO(g)

Accepted Answer

A)  -23.0 kJ 
B)  46 kJ 
C)  - 46 kJ 
D)  - 11.5 kJ 
E)  23.0 kJ 
A)  -23.0 kJ 
B)  46 kJ 
C)  - 46 kJ 
D)  - 11.5 kJ 
E)  23.0 kJ

Question 7

Calculate ΔGrxn at 298 K under the conditions shown below for the following reaction. SO3(g)+ H2O(g)→ H2SO4(l)ΔG°= -90.5 kJ
P(SO3)= 0.20 atm,P(H2O)= 0.88 atm

Accepted Answer

A)  -90.5 kJ 
B)  - 92.5 kJ 
C)  + 92.5 kJ 
D)  - 88.5 kJ 
E)  + 88.5 kJ 
A)  -90.5 kJ 
B)  - 92.5 kJ 
C)  + 92.5 kJ 
D)  - 88.5 kJ 
E)  + 88.5 kJ

Question 8

All of the following are examples of a spontaneous process EXCEPT

Accepted Answer

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. 
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 9

Given the following equation, N2O(g)+ NO2(g)→ 3 NO(g)ΔG°rxn = -23.0 kJ
Calculate ΔG°rxn for the following reaction.
15 NO(g)→ 5 N2O(g)+ 5 NO2(g)

Accepted Answer

A)  -23.0 kJ 
B)  115 kJ 
C)  - 115 kJ 
D)  - 4.60 kJ 
E)  23.0 kJ 
A)  -23.0 kJ 
B)  115 kJ 
C)  - 115 kJ 
D)  - 4.60 kJ 
E)  23.0 kJ

Question 10

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

Accepted Answer

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 
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 11

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

Accepted Answer

A)  ΔSsurr = +12.67 kJ/K, reaction is spontaneous 
B)  ΔSsurr = -12.67 kJ/K, reaction is spontaneous 
C)  ΔSsurr = +50.4 kJ/K, reaction is spontaneous 
D)  ΔSsurr = +3.18 kJ/K, reaction is spontaneous 
E)  ΔSsurr = -3.18 kJ/K, it is not possible to predict the spontaneity of this reaction without more information. 
A)  ΔSsurr = +12.67 kJ/K, reaction is spontaneous 
B)  ΔSsurr = -12.67 kJ/K, reaction is spontaneous 
C)  ΔSsurr = +50.4 kJ/K, reaction is spontaneous 
D)  ΔSsurr = +3.18 kJ/K, reaction is spontaneous 
E)  ΔSsurr = -3.18 kJ/K, it is not possible to predict the spontaneity of this reaction without more information.

Question 12

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

Accepted Answer

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

Question 13

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

Accepted Answer

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

Question 14

Which one of the following would be expected to have the lowest standard molar entropy,S°,at 25°C?

Accepted Answer

A)  C H4(g) 
B)  C3H6(g) 
C)  C3H8(g) 
D)  C4     OH(g) 
A)  C H4(g) 
B)  C3H6(g) 
C)  C3H8(g) 
D)  C4     OH(g)

Question 15

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

Accepted Answer

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

Question 16

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

Accepted Answer

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

Question 17

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

Accepted Answer

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. 
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 18

How many microstates are possible in a collection of four particles that are present,with two particles each in two connected flasks?
 Sketch them below.

Accepted Answer

There are six micros

Question 19

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

Accepted Answer

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

Question 20

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

Accepted Answer

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 
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

Exam 19: Free Energy and Thermodynamics

Why can't we say that a spontaneous reaction is a fast reaction?

For a given reaction,ΔH = -27.7 kJ/mol and ΔS = -76.6 J/Kmol.The reaction will have ΔG = 0 at ________ K.Assume that ΔH and ΔS do not vary with temperature.

Estimate ΔG°rxn for the following reaction at 417 K. HCN(g)+ 2 H2(g)→ CH3NH2(g)ΔH°= -158.0 kJ; ΔS°= -219.9 J/K

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

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

Given the following equation, N2O(g)+ NO2(g)→ 3 NO(g)ΔG°rxn = -23.0 kJ Calculate ΔG°rxn for the following reaction. 2 N2O(g)+ 2 NO2(g)→ 6 NO(g)

Calculate ΔGrxn at 298 K under the conditions shown below for the following reaction. SO3(g)+ H2O(g)→ H2SO4(l)ΔG°= -90.5 kJ P(SO3)= 0.20 atm,P(H2O)= 0.88 atm

All of the following are examples of a spontaneous process EXCEPT

Given the following equation, N2O(g)+ NO2(g)→ 3 NO(g)ΔG°rxn = -23.0 kJ Calculate ΔG°rxn for the following reaction. 15 NO(g)→ 5 N2O(g)+ 5 NO2(g)

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

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

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

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

Which one of the following would be expected to have the lowest standard molar entropy,S°,at 25°C?

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

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

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

How many microstates are possible in a collection of four particles that are present,with two particles each in two connected flasks? Sketch them below.

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

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

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Estimate ΔG°_rxn for the following reaction at 417 K. HCN(g)+ 2 H₂(g)→ CH₃NH₂(g)ΔH°= -158.0 kJ; ΔS°= -219.9 J/K

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

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

Given the following equation, N₂O(g)+ NO₂(g)→ 3 NO(g)ΔG°_rxn = -23.0 kJ Calculate ΔG°_rxn for the following reaction. 2 N₂O(g)+ 2 NO₂(g)→ 6 NO(g)

Calculate ΔG_rxn at 298 K under the conditions shown below for the following reaction. SO₃(g)+ H₂O(g)→ H₂SO₄(l)ΔG°= -90.5 kJ P(SO₃)= 0.20 atm,P(H₂O)= 0.88 atm

Given the following equation, N₂O(g)+ NO₂(g)→ 3 NO(g)ΔG°_rxn = -23.0 kJ Calculate ΔG°_rxn for the following reaction. 15 NO(g)→ 5 N₂O(g)+ 5 NO₂(g)

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

Consider the following reaction at constant P.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. 4 NH₃(g)+ 3 O₂(g)→ 2 N₂(g)+ 6 H₂O(g)ΔH = -1267 kJ

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

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