Question 1

You are given pure samples of pentane, CH3CH2CH2CH2CH3(l) , and 1,3-pentadiene, CH2=CHCH=CHCH3(l) . What prediction would you make concerning their standard molar entropies at 298 K?

Accepted Answer

A)  S° pentane > S° 1, 3-pentadiene
B)  S° pentane 1, 3-pentadiene
C)  S° pentane ≈ S° 1, 3-pentadiene
D)  S° pentane = S° 1, 3-pentadiene + 2 S°H 2
E)  More information is needed to make reasonable predictions.F) A) and B)
G) A) and C)

Question 2

Which one of the following changes of state increases the entropy of the system?

Accepted Answer

A)  Condensation
B)  Cooling a gas
C)  Freezing
D)  Crystallization
E)  SublimationF) A) and B)
G) C) and D)

Question 3

Which of the following is always true for an endothermic process?

Accepted Answer

A)  q sys > 0, Δ S surr 
B)  q sys surr > 0
C)  q sys surr 
D)  q sys > 0, Δ S surr > 0
E)  w < 0F) B) and E)
G) B) and D)

Question 4

Calculate ΔG° for the reaction SiCl4(g)  + 2Mg(s)  → 2MgCl2(s)  + Si(s) 
4(g)  + 2Mg(s)  → 2MgCl2(s)  + Si(s)    A) 566.60 kJ B) 50.38 kJ C) 25.19 kJ D) −25.19 kJ E) −566.60 kJ" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  566.60 kJ
B)  50.38 kJ
C)  25.19 kJ
D)  −25.19 kJ
E)  −566.60 kJF) B) and C)
G) A) and D)

Question 5

Iron(III)  oxide can be reduced by carbon monoxide. Fe2O3(s)  + 3CO(g)  ⇄ 2Fe(s)  + 3CO2(g) 
Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.
2O3(s)  + 3CO(g)  ⇄ 2Fe(s)  + 3CO2(g)  Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.   A) 7.0 × 10 −6 B) 1.3 × 10 −3 C) 2.2 × 10 4 D) 1.4 × 10 5 E) > 2.0 × 10 5" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  7.0 × 10 −6
B)  1.3 × 10 −3
C)  2.2 × 10 4
D)  1.4 × 10 5
E)  > 2.0 × 10 5F) A) and E)
G) None of the above

Exam 20: Thermodynamics: Entropy, Free Energy, and Reaction Direction

Which one of the following changes of state increases the entropy of the system?

Correct Answer
verified

Calculate ΔG° for the reaction SiCl₄(g) + 2Mg(s) → 2MgCl₂(s) + Si(s)

Correct Answer
verified

Which of the following is always true for an endothermic process?

Correct Answer
verified

You are given pure samples of pentane, CH₃CH₂CH₂CH₂CH₃(l) , and 1,3-pentadiene, CH₂=CHCH=CHCH₃(l) . What prediction would you make concerning their standard molar entropies at 298 K?

Correct Answer
verified

Iron(III) oxide can be reduced by carbon monoxide. Fe₂O₃(s) + 3CO(g) ⇄ 2Fe(s) + 3CO₂(g) Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

Correct Answer
verified

Exam 20: Thermodynamics: Entropy, Free Energy, and Reaction Direction

Which one of the following changes of state increases the entropy of the system?

Correct AnswerverifiedShow Answer

Calculate ΔG° for the reaction SiCl4(g) + 2Mg(s) → 2MgCl2(s) + Si(s)

Correct AnswerverifiedShow Answer

Which of the following is always true for an endothermic process?

Correct AnswerverifiedShow Answer

You are given pure samples of pentane, CH3CH2CH2CH2CH3(l) , and 1,3-pentadiene, CH2=CHCH=CHCH3(l) . What prediction would you make concerning their standard molar entropies at 298 K?

Correct AnswerverifiedShow Answer

Iron(III) oxide can be reduced by carbon monoxide. Fe2O3(s) + 3CO(g) ⇄ 2Fe(s) + 3CO2(g) Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Calculate ΔG° for the reaction SiCl₄(g) + 2Mg(s) → 2MgCl₂(s) + Si(s)

Correct Answer
verified

Correct Answer
verified

You are given pure samples of pentane, CH₃CH₂CH₂CH₂CH₃(l) , and 1,3-pentadiene, CH₂=CHCH=CHCH₃(l) . What prediction would you make concerning their standard molar entropies at 298 K?

Correct Answer
verified

Iron(III) oxide can be reduced by carbon monoxide. Fe₂O₃(s) + 3CO(g) ⇄ 2Fe(s) + 3CO₂(g) Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature.

Correct Answer
verified