Deck 8: Chemical Equilibrium

Question 1

Consider the following reaction in aqueous solution:
2A + 3B + C D + E
Which of the following is the correct law of mass action for this reaction?

A) K_c=[2A][3B][C][D]^-1[E]^-1
B) K_c=[A]²[B]³[C] \ [D][E]
C) K_c=[A]^-2[B]^-3[C]^-1[D][E]
D) K_c=[D][E] / [A]^-2[B]^-3[C]

Answer 1

K_c=[A]^-2[B]^-3[C]^-1[D][E]

Question 2

At 25°C, Kp=2.86´10²⁴ for the reaction:
2SO₂(g) + O₂(g)2SO₃(g)
At this temperature, what is the value of Kp for the reaction
SO₃(g)SO₂(g) + O₂(g)

A) 1.69´10¹²
B) 5.91´10^-13
C) 2.86´10²⁴
D) 3.50´10^-25
E) There is not enough information to answer the question
F) None of the above

Answer 2

5.91´10^-13

Question 3

The following question(s) pertain to the equilibrium 2NO(g) + 2H₂(g) $\rightarrow$ N₂(g) + 2H₂O(g) with initial partial pressures of P_NO=0.3 atm,
=0.4 atm, =0.4 atm.

-Refer to Exhibit 14-1. At a certain temperature equilibrium is established and it is determined that the partial pressure of water is 0.228 atm. What are the equilibrium partial pressures of NO, H2, and N2 respectively?

A) 0.172 atm, 0.172 atm, 0.472 atm
B) 0.192 atm, 0.192 atm, 0.466 atm,
C) 0.578 atm, 0.172 atm, 0.578 atm
D) 0.114 atm, 0.114 atm, 0.472 atm

Answer 3

0.172 atm, 0.172 atm, 0.472 atm

Question 4

pertain to the equilibrium 2NO(g) + 2H₂(g) $\rightarrow$ N₂(g) + 2H₂O(g) with initial partial pressures of P_NO=0.3 atm,
=0.4 atm, =0.4 atm.


-Refer to Exhibit 14-1. What is the numerical value of the equilibrium constant Kp at this temperature

A) 3.63
B) .275
C) 28.0
D) .483
E) None of the above

Question 5

pertain to the equilibrium 2NO(g) + 2H₂(g) $\rightarrow$ N₂(g) + 2H₂O(g) with initial partial pressures of P_NO=0.3 atm,
=0.4 atm, =0.4 atm.


-Refer to Exhibit 14-1. What is the numerical value of the thermodynamic equilibrium constant K at this temperature

A) 28.0
B) 3.63
C) 1.13
D) .483
E) Not enough information is given to answer the question
F) None of the above

Question 6

At 100 C, the following two reactions have the denoted equilibrium constants.
What is the value of the equilibrium constant for the reaction?
2NOBr(g) + C_l2(g) 2NO(g) + 2BrCl(g)

A) 180
B) 0.055
C) 3.125
D) .320
E) None of the above

Question 7

pertain to the reaction H₂(g) + I₂(g) 2HI(g) at 150°C with the reaction vessel being charged in such a way that the initial partial pressure of all the species in the reaction (both reactants and products) is 0.200 atm.


-Refer to Exhibit 14-2. What is the value of Q?

A) 1.00
B) 5.00
C) 0.200
D) 0.100
E) None of the above

Question 8

pertain to the reaction H₂(g) + I₂(g) 2HI(g) at 150°C with the reaction vessel being charged in such a way that the initial partial pressure of all the species in the reaction (both reactants and products) is 0.200 atm.


-Refer to Exhibit 14-2. Based on the equilibrium constant and the value of Q, will more reactants or products be formed as the system approaches equilibrium at this temperature?

A) More products will be formed
B) More reactants will be formed
C) Not enough data to answer the question
D) None of the above

Question 9

pertain to the reaction H₂(g) + I₂(g) 2HI(g) at 150°C with the reaction vessel being charged in such a way that the initial partial pressure of all the species in the reaction (both reactants and products) is 0.200 atm.


-Refer to Exhibit 14-2. What will be the partial pressure of HI when the system reaches equilibrium?

A) 0.200 atm
B) 0.037 atm
C) 0.526 atm
D) 0.373 atm
E) Not enough data to answer the question
F) None of the above

Question 10

pertain to the reaction N₂(g) + 3H₂(g) 2NH₃(g) at 200°C with the reaction vessel being charged in such a way that the initial partial pressures of N₂, H₂, and NH₃ are 0.200, 0.300, and 0.600 atm respectively.


-Refer to Exhibit 14-3. What is the value of the equilibrium constant K_p at this temperature?

A) 0.652
B) 2.78´10^-21
C) 3.59´10²⁰
D) 1.92´10^-14
E) None of the above

Question 11

pertain to the reaction N₂(g) + 3H₂(g) 2NH₃(g) at 200°C with the reaction vessel being charged in such a way that the initial partial pressures of N₂, H₂, and NH₃ are 0.200, 0.300, and 0.600 atm respectively.


-Refer to Exhibit 14-3. Based on the equilibrium constant and the value of Q, will more reactants or products be formed as the system approaches equilibrium at this temperature?

A) More products will be formed
B) More reactants will be formed
C) Not enough data to answer the question

Question 12

pertain to the reaction N₂(g) + 3H₂(g) 2NH₃(g) at 200°C with the reaction vessel being charged in such a way that the initial partial pressures of N₂, H₂, and NH₃ are 0.200, 0.300, and 0.600 atm respectively.


-Refer to Exhibit 14-3. What will be the total pressure in the reaction vessel when the system reaches equilibrium at this temperature?

A) 1.24 atm
B) 0.900 atm
C) 0.744 atm
D) 0.305 atm
E) None of the above

Question 13

At room temperature cyclohexane exists almost exclusively in the chair conformation (99.99%). But at 800°C, 30% of the cyclohexane molecules exist in the twist-boat conformation.
Compared to its value at 25°C, the value of DG° at 800°C for the reaction
C₆H₁₂(chair) C₆H₁₂(twist-boat)
Should

A) be larger in magnitude and have the same sign
B) be larger in magnitude and have the opposite sign
C) be smaller in magnitude and have the same sign
D) be smaller in magnitude and have the opposite sign
E) not enough information to answer the question