Question 1

Consider the following equilibrium:
4NH3(g) + 3O2(g) ⇌ 2N2(g) + 6H2O(g) + 1531 kJ
The concentrations of the reactants would decrease after ammonia was added to the system.

Accepted Answer

A) True 
 B)False

Question 2

If one starts with pure NO2(g)  at a pressure of 0.500 atm, the total pressure inside the reaction vessel when 2NO2(g)   ⇌\rightleftharpoons⇌  2NO(g)  + O2(g)  reaches equilibrium is 0.674 atm. Calculate the equilibrium partial pressure of NO2.

Accepted Answer

A)   0.152 atm
B)   0.174 atm
C)   0.200 atm
D)   0.326 atm
E)   The total pressure cannot be calculated because Kp is not given F) A) and C)
G) A) and E)

Question 3

Which of the following rate laws is consistent with the following mechanism
A(g)  + B(g)  ⇌ AB(g)  fast equilibrium (Kc1) 
AB(g)  + C(g)   →\rarr→  AC(g)  + B(g)  slow

Accepted Answer

A)   Rate = k[A][B]
B)   Rate = kKc1[A][B][C]
C)   Rate = k[AC][B]/[AB][C]
D)   Rate = [AB]/[A][B]
E)   Rate = Kc1[AC]/[A][C] F) C) and D)
G) A) and B)

Question 4

The equilibrium constant expression for the reaction: 
N2 (g)  + O2 (g)   ⇌\rightleftharpoons⇌  2NO (g)  is

Accepted Answer

A)   Kc = 2[NO]/[N2][O2]
B)   Kc = [N2][O2]/2[NO]
C)   Kc = [N2][O2]/[NO]2
D)   Kc = [NO]2/[N2][O2]
E)   Kc = [NO]/[N2][O2] F) A) and C)
G) A) and D)

Question 5

Hydrogen iodide decomposes according to the equation: 2HI(g)  ⇌ H2(g)  + I2(g) , Kc = 0.0156 at 400ºC
a 0.660 mol sample of HI was injected into a 2.00 L reaction vessel held at 400ºC.Calculate the concentration of H2 equilibrium.

Accepted Answer

A)   0.013 M
B)   0.033 M
C)   0.053 M
D)   0.073 M
E)   None of the aboveF) A) and B)
G) B) and D)

Question 6

The reaction A(g)  + 2B(g)   ⇌\rightleftharpoons⇌  C(g)  was allowed to come to equilibrium. The initial amounts of reactants placed into a 5.00 L vessel were 1.0 mol A and 1.8 molB. After the reaction reached equilibrium, 1.0 mol of B was found. Calculate Kc for this reaction.

Accepted Answer

A)   0.060
B)   5.1
C)   17
D)   19
E)   25 F) A) and D)
G) A) and C)

Question 7

The Kc for the reaction CO2(g)  + H2(g)  ⇌ H2O(g)  + CO(g)  is 1.6 at about 990ºC. Calculate the number of moles of hydrogen gas in the final equilibrium system obtained by initially adding 1.00 mol of H2, 2.00 mol of CO2, 0.750 mol of H2O, and 1.00 mol of CO to a 5.00 L reactor at 990ºC.

Accepted Answer

A)   0.42 mol
B)   0.62 mol
C)   0.82 mol
D)   1.02 mol
E)   None of the aboveF) B) and E)
G) B) and C)

Question 8

When the reaction 2O3(g) ⇌ 3O2(g), for which Kp = 3.0 * 1026 at 773ºC, is at equilibrium, the mixture will contain very little O2 as compared to O3.

Accepted Answer

A) True 
 B)False

Question 9

For the following reaction at equilibrium in a reaction vessel, which change will cause the Br2 concentration to decrease
2NOBr(g)  ⇌ 2NO(g)  + Br2(g) ,  Δ\DeltaΔ Hºrxn= 30 kJ/mol

Accepted Answer

A)   Increase the temperature.
B)   Remove some NO.
C)   Add more NOBr.
D)   Compress the gas mixture into a smaller volume.
E)   Add a catalyst F) B) and C)
G) C) and E)

Question 10

At 35ºC, the equilibrium constant for the reaction 2NOCl(g)   ⇌\rightleftharpoons⇌  2NO(g)  + Cl2(g)  is Kc = 1.6 * 10-5. An equilibrium mixture was found to have the following concentrations of Cl2 and NOCl: [Cl2] = 1.2 * 10-2 M; [NOCl] = 2.8 * 10-1 M. Calculate the concentration of NO(g)  at equilibrium.

Accepted Answer

A)   1.0 * 10-4 M
B)   1.0 * 10-2 M
C)   2.8 * 10-1 M
D)   2.4 * 10-2 M
E)   1.6 * 10-3 M F) B) and C)
G) A) and E)

Question 11

The equilibrium constant expression for the following reaction
CuO(s) + H2(g) ⇌ Cu(s) + H2O(g) is Kc = [H2]/[H2O].

Accepted Answer

A) True 
 B)False

Question 12

Solid ammonium hydrogen sulfide is introduced into a 2.00-L flask, and the flask is sealed. If this solid decomposes according to the equation below 
NH4HS(s)  ⇌ NH3(g)  + H2S(g) , Kp = 0.108 at 25 ∘\circ∘ C,
What is the minimum mass of ammonium hydrogen sulfide that must be present in the flask initially if equilibrium is to be established at 25 ∘\circ∘ C

Accepted Answer

A)   0.917 g
B)   1.37 g
C)   2.74 g
D)   0.581 g
E)   0.452 g F) B) and E)
G) B) and C)

Question 13

Consider the chemical reaction 2NH3(g)  ⇌ N2(g)  + 3H2(g) . The equilibrium is to be established in a 1.0 L container at 1,000 K, where Kc = 4.0 * 10-2. Initially, 1,220 moles of NH3(g)  are present. Calculate Kp for the reaction.

Accepted Answer

A)   210
B)   230
C)   250
D)   270
E)   None of the aboveF) A) and E)
G) A) and C)

Question 14

Which of these situations will result if some CH4(g)  is removed from the reaction CO(g)  + 3H2(g)  ⇌ CH4(g)  + H2O(g)  at equilibrium

Accepted Answer

A)   H2O will be consumed.
B)   More CH4 and H2O will be produced.
C)   Kp will decrease.
D)   More CO will be produced.
E)   No change will occur.F) B) and D)
G) A) and C)

Question 15

Consider the following equilibrium:
4NH3(g) + 3O2(g) ⇌ 2N2(g) + 6H2O(g) + 1531 kJ
The concentrations the reactants would increase after nitrogen gas was removed from the system.

Accepted Answer

A) True 
 B)False

Question 16

At 400ºC, Kc = 64 for the equilibrium H2(g)  + I2(g)  (⇌)  2HI(g) . If 3.00 mol H2 and 3.00 mol I2 are introduced into an empty 4.0 L vessel, find the equilibrium concentration of HI at 400ºC.

Accepted Answer

A)   0.15 M
B)   1.2 M
C)   2.4 M
D)   4.8 M
E)   5.8 MF) None of the above
G) C) and D)

Question 17

75.0 g of PCl5(g)  is introduced into an evacuated 3.00 L vessel and allowed to reach equilibrium at 250ºC.PCl5(g)  ⇌ PCl3(g)  + Cl2(g)  If Kp = 1.80 for this reaction, what is the total pressure inside the vessel at equilibrium

Accepted Answer

A)   2.88 atm
B)   2.27 atm
C)   4.54 atm
D)   7.42 atm
E)   9.69 atmF) A) and C)
G) All of the above

Question 18

The solubility of silver bromide can be increased by dissolving it in a solution containing the thiosulfate anion.
AgBr(s)   ⇌\rightleftharpoons⇌  Ag+ (aq)  + Br- (aq)  K1 = 7.7 x 10-13 
Ag+(aq)  + 2S2O32- (aq)   ⇌\rightleftharpoons⇌  Ag(S2O3) 23- (aq)  K2 = 4.7 x 1013
What is the value of the equilibrium constant for the overall reaction
AgBr(s)  + 2S2O32-(aq)   ⇌\rightleftharpoons⇌  Ag(S2O3) 23-(aq)  + Br-(aq)

Accepted Answer

A)   3.6 x 10-9
B)   12.4 x 1013
C)   4.7 x 10-9
D)   4.7 x 1013
E)   36 F) None of the above
G) D) and E)

Question 19

Given the following information: 2A(g)  + B(g)   ⇌\rightleftharpoons⇌  A2B(g)  Kp1
2A(g)  + C2(g)   ⇌\rightleftharpoons⇌  2AC(g)  Kp2
3/2 A2 + B(g)  + C(g)   ⇌\rightleftharpoons⇌  AC(g)  + A2B(g)  Kp3
Which relationship represents the equilibrium constant for the reaction:
4A(g)  + C2(g)  + A2B(g)   ⇌\rightleftharpoons⇌  3A2(g)  + B(g)  + 2C(g)

Accepted Answer

A)   Knet = Kp1 x Kp2 x Kp3
B)   Knet = Kp1 x Kp2 x 2 Kp3
C)   Knet = Kp1 x Kp2 x Kp32
D)   Knet = Kp1 x Kp2/ Kp3
E)   Knet = Kp1 x Kp2/ Kp32 F) A) and E)
G) B) and D)

Exam 14: Chemical Equilibrium

Correct Answer
verified

75.0 g of PCl₅(g) is introduced into an evacuated 3.00 L vessel and allowed to reach equilibrium at 250ºC.PCl₅(g) ⇌ PCl₃(g) + Cl₂(g) If K_p = 1.80 for this reaction, what is the total pressure inside the vessel at equilibrium

Correct Answer
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At 400ºC, K_c = 64 for the equilibrium H₂(g) + I₂(g) (⇌) 2HI(g) . If 3.00 mol H₂ and 3.00 mol I₂ are introduced into an empty 4.0 L vessel, find the equilibrium concentration of HI at 400ºC.

Correct Answer
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Consider the following equilibrium: 4NH₃(g) + 3O₂(g) ⇌ 2N₂(g) + 6H₂O(g) + 1531 kJ The concentrations the reactants would increase after nitrogen gas was removed from the system.

Correct Answer
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The reaction A(g) + 2B(g) $\rightleftharpoons$ C(g) was allowed to come to equilibrium. The initial amounts of reactants placed into a 5.00 L vessel were 1.0 mol A and 1.8 molB. After the reaction reached equilibrium, 1.0 mol of B was found. Calculate K_c for this reaction.

Correct Answer
verified

Correct Answer
verified

For the following reaction at equilibrium in a reaction vessel, which change will cause the Br₂ concentration to decrease 2NOBr(g) ⇌ 2NO(g) + Br₂(g) , $\Delta$ Hº_rxn= 30 kJ/mol

Correct Answer
verified

Correct Answer
verified

If one starts with pure NO₂(g) at a pressure of 0.500 atm, the total pressure inside the reaction vessel when 2NO₂(g) $\rightleftharpoons$ 2NO(g) + O₂(g) reaches equilibrium is 0.674 atm. Calculate the equilibrium partial pressure of NO₂.

Correct Answer
verified

The equilibrium constant expression for the following reaction CuO(s) + H₂(g) ⇌ Cu(s) + H₂O(g) is K_c = [H₂]/[H₂O].

Correct Answer
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When the reaction 2O₃(g) ⇌ 3O₂(g), for which K_p = 3.0 * 10²⁶ at 773ºC, is at equilibrium, the mixture will contain very little O₂ as compared to O₃.

Correct Answer
verified

Hydrogen iodide decomposes according to the equation: 2HI(g) ⇌ H₂(g) + I₂(g) , K_c = 0.0156 at 400ºC a 0.660 mol sample of HI was injected into a 2.00 L reaction vessel held at 400ºC.Calculate the concentration of H₂ equilibrium.

Correct Answer
verified

Correct Answer
verified

Which of these situations will result if some CH₄(g) is removed from the reaction CO(g) + 3H₂(g) ⇌ CH₄(g) + H₂O(g) at equilibrium

Correct Answer
verified

Consider the following equilibrium: 4NH₃(g) + 3O₂(g) ⇌ 2N₂(g) + 6H₂O(g) + 1531 kJ The concentrations of the reactants would decrease after ammonia was added to the system.

Correct Answer
verified

Correct Answer
verified

The equilibrium constant expression for the reaction: N₂ (g) + O₂ (g) $\rightleftharpoons$ 2NO (g) is

Correct Answer
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Consider the chemical reaction 2NH₃(g) ⇌ N₂(g) + 3H₂(g) . The equilibrium is to be established in a 1.0 L container at 1,000 K, where K_c = 4.0 * 10^-2. Initially, 1,220 moles of NH₃(g) are present. Calculate K_p for the reaction.

Correct Answer
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Which of the following rate laws is consistent with the following mechanism A(g) + B(g) ⇌ AB(g) fast equilibrium (K_c1) AB(g) + C(g) $\rarr$ AC(g) + B(g) slow

Correct Answer
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Exam 14: Chemical Equilibrium

The Kc for the reaction CO2(g) + H2(g) ⇌ H2O(g) + CO(g) is 1.6 at about 990ºC. Calculate the number of moles of hydrogen gas in the final equilibrium system obtained by initially adding 1.00 mol of H2, 2.00 mol of CO2, 0.750 mol of H2O, and 1.00 mol of CO to a 5.00 L reactor at 990ºC.

Correct AnswerverifiedShow Answer

75.0 g of PCl5(g) is introduced into an evacuated 3.00 L vessel and allowed to reach equilibrium at 250ºC.PCl5(g) ⇌ PCl3(g) + Cl2(g) If Kp = 1.80 for this reaction, what is the total pressure inside the vessel at equilibrium

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At 400ºC, Kc = 64 for the equilibrium H2(g) + I2(g) (⇌) 2HI(g) . If 3.00 mol H2 and 3.00 mol I2 are introduced into an empty 4.0 L vessel, find the equilibrium concentration of HI at 400ºC.

Correct AnswerverifiedShow Answer

Consider the following equilibrium: 4NH3(g) + 3O2(g) ⇌ 2N2(g) + 6H2O(g) + 1531 kJ The concentrations the reactants would increase after nitrogen gas was removed from the system.

Correct AnswerverifiedShow Answer

The reaction A(g) + 2B(g) ⇌\rightleftharpoons⇌ C(g) was allowed to come to equilibrium. The initial amounts of reactants placed into a 5.00 L vessel were 1.0 mol A and 1.8 molB. After the reaction reached equilibrium, 1.0 mol of B was found. Calculate Kc for this reaction.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

For the following reaction at equilibrium in a reaction vessel, which change will cause the Br2 concentration to decrease 2NOBr(g) ⇌ 2NO(g) + Br2(g) , Δ\DeltaΔ Hºrxn= 30 kJ/mol

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

If one starts with pure NO2(g) at a pressure of 0.500 atm, the total pressure inside the reaction vessel when 2NO2(g) ⇌\rightleftharpoons⇌ 2NO(g) + O2(g) reaches equilibrium is 0.674 atm. Calculate the equilibrium partial pressure of NO2.

Correct AnswerverifiedShow Answer

The equilibrium constant expression for the following reaction CuO(s) + H2(g) ⇌ Cu(s) + H2O(g) is Kc = [H2]/[H2O].

Correct AnswerverifiedShow Answer

When the reaction 2O3(g) ⇌ 3O2(g), for which Kp = 3.0 * 1026 at 773ºC, is at equilibrium, the mixture will contain very little O2 as compared to O3.

Correct AnswerverifiedShow Answer

Hydrogen iodide decomposes according to the equation: 2HI(g) ⇌ H2(g) + I2(g) , Kc = 0.0156 at 400ºC a 0.660 mol sample of HI was injected into a 2.00 L reaction vessel held at 400ºC.Calculate the concentration of H2 equilibrium.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which of these situations will result if some CH4(g) is removed from the reaction CO(g) + 3H2(g) ⇌ CH4(g) + H2O(g) at equilibrium

Correct AnswerverifiedShow Answer

Consider the following equilibrium: 4NH3(g) + 3O2(g) ⇌ 2N2(g) + 6H2O(g) + 1531 kJ The concentrations of the reactants would decrease after ammonia was added to the system.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The equilibrium constant expression for the reaction: N2 (g) + O2 (g) ⇌\rightleftharpoons⇌ 2NO (g) is

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Consider the chemical reaction 2NH3(g) ⇌ N2(g) + 3H2(g) . The equilibrium is to be established in a 1.0 L container at 1,000 K, where Kc = 4.0 * 10-2. Initially, 1,220 moles of NH3(g) are present. Calculate Kp for the reaction.

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Which of the following rate laws is consistent with the following mechanism A(g) + B(g) ⇌ AB(g) fast equilibrium (Kc1) AB(g) + C(g) →\rarr→ AC(g) + B(g) slow

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Correct Answer
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75.0 g of PCl₅(g) is introduced into an evacuated 3.00 L vessel and allowed to reach equilibrium at 250ºC.PCl₅(g) ⇌ PCl₃(g) + Cl₂(g) If K_p = 1.80 for this reaction, what is the total pressure inside the vessel at equilibrium

Correct Answer
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At 400ºC, K_c = 64 for the equilibrium H₂(g) + I₂(g) (⇌) 2HI(g) . If 3.00 mol H₂ and 3.00 mol I₂ are introduced into an empty 4.0 L vessel, find the equilibrium concentration of HI at 400ºC.

Correct Answer
verified

Consider the following equilibrium: 4NH₃(g) + 3O₂(g) ⇌ 2N₂(g) + 6H₂O(g) + 1531 kJ The concentrations the reactants would increase after nitrogen gas was removed from the system.

Correct Answer
verified

The reaction A(g) + 2B(g) $\rightleftharpoons$ C(g) was allowed to come to equilibrium. The initial amounts of reactants placed into a 5.00 L vessel were 1.0 mol A and 1.8 molB. After the reaction reached equilibrium, 1.0 mol of B was found. Calculate K_c for this reaction.

Correct Answer
verified

Correct Answer
verified

For the following reaction at equilibrium in a reaction vessel, which change will cause the Br₂ concentration to decrease 2NOBr(g) ⇌ 2NO(g) + Br₂(g) , $\Delta$ Hº_rxn= 30 kJ/mol

Correct Answer
verified

Correct Answer
verified

If one starts with pure NO₂(g) at a pressure of 0.500 atm, the total pressure inside the reaction vessel when 2NO₂(g) $\rightleftharpoons$ 2NO(g) + O₂(g) reaches equilibrium is 0.674 atm. Calculate the equilibrium partial pressure of NO₂.

Correct Answer
verified

The equilibrium constant expression for the following reaction CuO(s) + H₂(g) ⇌ Cu(s) + H₂O(g) is K_c = [H₂]/[H₂O].

Correct Answer
verified

When the reaction 2O₃(g) ⇌ 3O₂(g), for which K_p = 3.0 * 10²⁶ at 773ºC, is at equilibrium, the mixture will contain very little O₂ as compared to O₃.

Correct Answer
verified

Hydrogen iodide decomposes according to the equation: 2HI(g) ⇌ H₂(g) + I₂(g) , K_c = 0.0156 at 400ºC a 0.660 mol sample of HI was injected into a 2.00 L reaction vessel held at 400ºC.Calculate the concentration of H₂ equilibrium.

Correct Answer
verified

Correct Answer
verified

Which of these situations will result if some CH₄(g) is removed from the reaction CO(g) + 3H₂(g) ⇌ CH₄(g) + H₂O(g) at equilibrium

Correct Answer
verified

Consider the following equilibrium: 4NH₃(g) + 3O₂(g) ⇌ 2N₂(g) + 6H₂O(g) + 1531 kJ The concentrations of the reactants would decrease after ammonia was added to the system.

Correct Answer
verified

Correct Answer
verified

The equilibrium constant expression for the reaction: N₂ (g) + O₂ (g) $\rightleftharpoons$ 2NO (g) is

Correct Answer
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Consider the chemical reaction 2NH₃(g) ⇌ N₂(g) + 3H₂(g) . The equilibrium is to be established in a 1.0 L container at 1,000 K, where K_c = 4.0 * 10^-2. Initially, 1,220 moles of NH₃(g) are present. Calculate K_p for the reaction.

Correct Answer
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Which of the following rate laws is consistent with the following mechanism A(g) + B(g) ⇌ AB(g) fast equilibrium (K_c1) AB(g) + C(g) $\rarr$ AC(g) + B(g) slow

Correct Answer
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