Question 1

The figure below represents the spontaneous reaction of H2 (shaded spheres) with O2 (unshaded spheres) to produce gaseous H2O. 2 (shaded spheres) with O2 (unshaded spheres) to produce gaseous H2O.   -What are the signs (+,or -) of ΔH,ΔS,and ΔG for this process? A) ΔH = +,ΔS = +,ΔG = + B) ΔH = +,ΔS = +,ΔG = - C) ΔH = -,ΔS = -,ΔG = + D) ΔH = -,ΔS = -,ΔG = -" class="answers-bank-image d-inline" rel="preload" >
-What are the signs (+,or -) of ΔH,ΔS,and ΔG for this process?

Accepted Answer

A)  ΔH = +,ΔS = +,ΔG = +
B)  ΔH = +,ΔS = +,ΔG = -
C)  ΔH = -,ΔS = -,ΔG = +
D)  ΔH = -,ΔS = -,ΔG = -E) A) and B)
F) A) and C)

Question 2

If ΔG° is negative for a reaction,

Accepted Answer

A)  K 
B)  K = 0.
C)  K is between 0 and 1.
D)  K > 1.E) A) and C)
F) B) and C)

Question 3

A hot penny is dropped into cold water inside a polystyrene foam cup.Assuming negligible heat loss to the atmosphere and the cup,

Accepted Answer

A)  the decrease in entropy of the penny is equal to the increase in entropy of the water.∣ ΔSpenny ∣ = ∣ ΔSwater ∣
B)  the decrease in entropy of the penny is less than the increase in entropy of the water.∣ ΔSpenny ∣ water ∣
C)  the decrease in entropy of the penny is more than the increase in entropy of the water.∣ ΔSpenny ∣ > ∣ ΔSwater ∣
D)  the entropy of both the penny and the water increases.E) B) and C)
F) A) and D)

Question 4

Which of the following is true?

Accepted Answer

A)  As a reaction at constant temperature and pressure goes to equilibrium,|ΔG| decreases.
B)  The larger ΔG°,the faster the reaction.
C)  The standard state for solutes is the pure solute at 1 atm.
D)  When a reaction reaches equilibrium,ΔG° = 0.E) All of the above
F) A) and D)

Question 5

For the vaporization of solid rhombic sulfur,S(s,rhombic)⇌ S(g),ΔG° = 236.7 kJ/mol.At 25°C the vapor pressure of rhombic sulfur is ________ atm.

Accepted Answer

The answer of For the vaporization of solid rhombic sulfur,S(s,rhombic)⇌...

Question 6

Consider the reaction 2A(g) ⇌ A2(g) .The following pictures represent two possible initial states and the equilibrium state of the system. 2(g) .The following pictures represent two possible initial states and the equilibrium state of the system.   -What are the signs (+ or -) of ΔH,ΔS,and ΔG when the system spontaneously goes from initial state 2 to the equilibrium state? A) ΔH = +,ΔS = +,ΔG = + B) ΔH = +,ΔS = +,ΔG = - C) ΔH = -,ΔS = -,ΔG = + D) ΔH = -,ΔS = -,ΔG = -" class="answers-bank-image d-inline" rel="preload" >
-What are the signs (+ or -) of ΔH,ΔS,and ΔG when the system spontaneously goes from initial state 2 to the equilibrium state?

Accepted Answer

A)  ΔH = +,ΔS = +,ΔG = +
B)  ΔH = +,ΔS = +,ΔG = -
C)  ΔH = -,ΔS = -,ΔG = +
D)  ΔH = -,ΔS = -,ΔG = -E) A) and B)
F) A) and C)

Question 7

For a reaction at constant temperature,as Q increases

Accepted Answer

A)  ΔG and ΔG° increase.
B)  ΔG and ΔG° decrease.
C)  ΔG increases,but ΔG° remains constant.
D)  ΔG decreases,but ΔG° remains constant.E) B) and D)
F) None of the above

Question 8

Chemical and physical changes can be classified as spontaneous or nonspontaneous.At 25°C and 1 atm pressure the decomposition of water into hydrogen and oxygen is classified as ________,and the melting of snow is classified as ________.

Accepted Answer

nonspontan...

Question 9

Which of the following must be true in order for this reaction to always proceed spontaneously?

Accepted Answer

A)  K = Q
B)  K > Q
C)  K 
D)  None of these,spontaneity is dependent on reaction conditions.E) B) and D)
F) A) and B)

Question 10

A reaction has ΔH° = 61.9 kJ/mol and ΔS° = 405.4 J/K.Is this reaction spontaneous or nonspontaneous? At what temperature (if any) can the spontaneity be reversed?

Accepted Answer

A)  nonspontaneous,can be made spontaneous at 153 K
B)  nonspontaneous,cannot be made spontaneous at any temperature
C)  spontaneous,can be made nonspontaneous at 153 K
D)  spontaneous,cannot be made nonspontaneous at any temperatureE) A) and C)
F) A) and B)

Question 11

At high temperatures boron carbide vaporizes according to the equation B4C(s) ⇌ 4 B(g) + C(s) 
Which equation describes the relationship between ΔG° and ΔG for this reaction?

Accepted Answer

A)  ΔG = ΔG° + R T ln (pB ∙ [C]/[B4C]) 
B)  ΔG = ΔG° + R T ln pB
C)  ΔG = ΔG° + 4 R T ln pB
D)  ΔG = ΔG° - 4 R T ln pBE) C) and D)
F) A) and C)

Question 12

At constant pressure and temperature,which statement is true?

Accepted Answer

A)  All reactions for which ΔH 
B)  All reactions for which ΔS 
C)  All reactions for which ΔG 
D)  All reactions for which K < 1 are spontaneous.E) A) and D)
F) All of the above

Question 13

For which of the following will the entropy of the system increase?

Accepted Answer

A)  condensation of steam
B)  reaction of zinc with oxygen to form zinc oxide
C)  reaction of nitrogen and hydrogen to form ammonia
D)  sublimation of dry iceE) A) and D)
F) B) and D)

Question 14

Which substance has the highest standard molar entropy at 25°C?

Accepted Answer

A)  C(graphite) 
B)  C2H4(g) 
C)  CH3OCH3(l) 
D)  BaCO3(s) E) B) and C)
F) C) and D)

Question 15

Without doing any calculations,determine whether the standard entropy change,ΔS° is positive or negative for each of the following reactions. reaction 1: C(graphite) + O2(g) → CO2(g) 
Reaction 2: 2 CO(g) + O2(g) → 2 CO2(g)

Accepted Answer

A)  ΔS° is positive for both reactions.
B)  ΔS° is positive for reaction 1 but negative for reaction 2.
C)  ΔS° is positive for reaction 2 but negative for reaction 1.
D)  ΔS° is negative for both reactions.E) A) and B)
F) C) and D)

Question 16

Consider the following gas-phase reaction of A2 (shaded spheres) and B2 (unshaded spheres) :
A2(g) + B2(g) ⇌ 2 AB(g) ΔG ° = +25 kJ 2 (shaded spheres) and B2 (unshaded spheres) : A2(g) + B2(g) ⇌ 2 AB(g) ΔG ° = +25 kJ   -Which of the above reaction mixtures is ΔG of reaction = ΔG °? A) (1)  B) (2)  C) (3)  D) (4) " class="answers-bank-image d-inline" rel="preload" >
-Which of the above reaction mixtures is ΔG of reaction = ΔG °?

Accepted Answer

A)  (1) 
B)  (2) 
C)  (3) 
D)  (4) E) B) and C)
F) A) and D)

Question 17

Which has the highest entropy in each set? I.H2O(s) ,H2O(l) ,H2O(g) at 0.1°C,4.40 atm
II.H2O(l) at 0°C,H2O(l) at 23°C,H2O(l) at 100°C (all at 1.0 atm pressure)

Accepted Answer

A)  H2O(l) in set I and H2O(l) at 0°C in set II
B)  H2O(s) in set I and H2O(l) at 100°C in set II
C)  H2O(g) in set I and H2O(l) at 0°C in set II
D)  H2O(g) in set I and H2O(l) at 100°C in set IIE) A) and C)
F) B) and D)

Question 18

For a process to be at equilibrium,it is necessary that

Accepted Answer

A)  ΔSsys = ΔSsurr.
B)  ΔSsys = -ΔSsurr.
C)  ΔSsys = 0.
D)  ΔSsys = 0 and ΔSsurr = 0.E) A) and B)
F) A) and C)

Question 19

Consider the reaction 2A(g) ⇌ A2(g) .The following pictures represent two possible initial states and the equilibrium state of the system. 2(g) .The following pictures represent two possible initial states and the equilibrium state of the system.   -For initial state 2 what is the relationship between the reaction quotient,Qp,and the equilibrium constant,Kp? A) Qp p B) Qp = Kp = 1 C) Qp = Kp ≠ 1 D) Qp > Kp" class="answers-bank-image d-inline" rel="preload" >
-For initial state 2 what is the relationship between the reaction quotient,Qp,and the equilibrium constant,Kp?

Accepted Answer

A)  Qp p
B)  Qp = Kp = 1
C)  Qp = Kp ≠ 1
D)  Qp > KpE) B) and D)
F) A) and C)

Question 20

Calculate Ksp for PbI2 at 25°C based on the following data: sp for PbI2 at 25°C based on the following data:   A) 4 × 10-31 B) 8 × 10-18 C) 9 × 10-9 D) 5 × 10-5" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  4 × 10-31
B)  8 × 10-18
C)  9 × 10-9
D)  5 × 10-5E) B) and D)
F) B) and C)

Exam 17: Thermodynamics: Entropy, free Energy, and Equilibrium

If ΔG° is negative for a reaction,

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A hot penny is dropped into cold water inside a polystyrene foam cup.Assuming negligible heat loss to the atmosphere and the cup,

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Without doing any calculations,determine whether the standard entropy change,ΔS° is positive or negative for each of the following reactions. reaction 1: C(graphite) + O2(g) → CO2(g) Reaction 2: 2 CO(g) + O2(g) → 2 CO2(g)

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Which of the following is true?

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Consider the following gas-phase reaction of A2 (shaded spheres) and B2 (unshaded spheres) : A2(g) + B2(g) ⇌ 2 AB(g) ΔG ° = +25 kJ -Which of the above reaction mixtures is ΔG of reaction = ΔG °?

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At constant pressure and temperature,which statement is true?

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The figure below represents the spontaneous reaction of H2 (shaded spheres) with O2 (unshaded spheres) to produce gaseous H2O. -What are the signs (+,or -) of ΔH,ΔS,and ΔG for this process?

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At high temperatures boron carbide vaporizes according to the equation B4C(s) ⇌ 4 B(g) + C(s) Which equation describes the relationship between ΔG° and ΔG for this reaction?

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For a process to be at equilibrium,it is necessary that

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For the vaporization of solid rhombic sulfur,S(s,rhombic)⇌ S(g),ΔG° = 236.7 kJ/mol.At 25°C the vapor pressure of rhombic sulfur is ________ atm.

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Which substance has the highest standard molar entropy at 25°C?

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For a reaction at constant temperature,as Q increases

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For which of the following will the entropy of the system increase?

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Consider the reaction 2A(g) ⇌ A2(g) .The following pictures represent two possible initial states and the equilibrium state of the system. -What are the signs (+ or -) of ΔH,ΔS,and ΔG when the system spontaneously goes from initial state 2 to the equilibrium state?

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A reaction has ΔH° = 61.9 kJ/mol and ΔS° = 405.4 J/K.Is this reaction spontaneous or nonspontaneous? At what temperature (if any) can the spontaneity be reversed?

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Which has the highest entropy in each set? I.H2O(s) ,H2O(l) ,H2O(g) at 0.1°C,4.40 atm II.H2O(l) at 0°C,H2O(l) at 23°C,H2O(l) at 100°C (all at 1.0 atm pressure)

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Consider the reaction 2A(g) ⇌ A2(g) .The following pictures represent two possible initial states and the equilibrium state of the system. -For initial state 2 what is the relationship between the reaction quotient,Qp,and the equilibrium constant,Kp?

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Chemical and physical changes can be classified as spontaneous or nonspontaneous.At 25°C and 1 atm pressure the decomposition of water into hydrogen and oxygen is classified as ________,and the melting of snow is classified as ________.

Correct Answerverifiednonspontan...View AnswerShow Answer

Which of the following must be true in order for this reaction to always proceed spontaneously?

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Calculate Ksp for PbI2 at 25°C based on the following data:

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Without doing any calculations,determine whether the standard entropy change,ΔS° is positive or negative for each of the following reactions. reaction 1: C(graphite) + O₂(g) → CO₂(g) Reaction 2: 2 CO(g) + O₂(g) → 2 CO₂(g)

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Correct Answer
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Consider the following gas-phase reaction of A₂ (shaded spheres) and B₂ (unshaded spheres) : A₂(g) + B₂(g) ⇌ 2 AB(g) ΔG ° = +25 kJ -Which of the above reaction mixtures is ΔG of reaction = ΔG °?

Correct Answer
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Correct Answer
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The figure below represents the spontaneous reaction of H₂ (shaded spheres) with O₂ (unshaded spheres) to produce gaseous H₂O. -What are the signs (+,or -) of ΔH,ΔS,and ΔG for this process?

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At high temperatures boron carbide vaporizes according to the equation B₄C(s) ⇌ 4 B(g) + C(s) Which equation describes the relationship between ΔG° and ΔG for this reaction?

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Correct Answer
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Consider the reaction 2A(g) ⇌ A₂(g) .The following pictures represent two possible initial states and the equilibrium state of the system. -What are the signs (+ or -) of ΔH,ΔS,and ΔG when the system spontaneously goes from initial state 2 to the equilibrium state?

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Which has the highest entropy in each set? I.H₂O(s) ,H₂O(l) ,H₂O(g) at 0.1°C,4.40 atm II.H₂O(l) at 0°C,H₂O(l) at 23°C,H₂O(l) at 100°C (all at 1.0 atm pressure)

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Consider the reaction 2A(g) ⇌ A₂(g) .The following pictures represent two possible initial states and the equilibrium state of the system. -For initial state 2 what is the relationship between the reaction quotient,Q_p,and the equilibrium constant,K_p?

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Chemical and physical changes can be classified as spontaneous or nonspontaneous.At 25°C and 1 atm pressure the decomposition of water into hydrogen and oxygen is classified as ,and the melting of snow is classified as .

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nonspontan...
View Answer

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Calculate K_sp for PbI₂ at 25°C based on the following data:

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