Deck 15: Chemical Equilibrium

Question 1

The K_eq for the equilibrium below is 7.52 × 10^-2 at 480.0°C. 2Cl₂ (g)+ 2H₂O (g) 4HCl (g)+ O₂ (g)
What is the value of K_eq at this temperature for the following reaction?
4HCl (g)+ O₂ (g) 2Cl₂ (g)+ 2H₂O (g)

A)0.0752
B)-0.0752
C)13.3
D)5.66 × 10^-3
E)0.150

Answer 1

13.3

Question 2

The equilibrium expression for K_p for the reaction below is __________. N₂ (g)+ O₂ (g) 2NO (g)

A)
B)
C)
D)
E)none of the above

Answer 2

none of the above

Question 3

The K_eq for the equilibrium below is 7.52 × 10^-2 at 480.0°C. 2Cl₂ (g)+ 2H₂O (g) 4HCl (g)+ O₂ (g)
What is the value of K_eq at this temperature for the following reaction?
2HCl (g)+ O₂ (g) Cl₂ (g)+ H₂O (g)

A)13.3
B)3.65
C)-0.0376
D)5.66 × 10^-3
E)0.274

Answer 3

3.65

Question 4

What role did Karl Bosch play in development of the Haber-Bosch process?

A)He discovered the reaction conditions necessary for formation of ammonia.
B)He originally isolated ammonia from camel dung and found a method for purifying it.
C)Haber was working in his lab with his instructor at the time he worked out the process.
D)He developed the equipment necessary for industrial production of ammonia.
E)He was the German industrialist who financed the research done by Haber.

Question 5

The equilibrium expression for K_p for the reaction below is __________. 2O₃ (g) 3O₂ (g)

A)
B)
C)
D)
E)

Question 6

Which one of the following is true concerning the Haber process?

A)It is a process used for shifting equilibrium positions to the right for more economical chemical synthesis of a variety of substances.
B)It is a process used for the synthesis of ammonia.
C)It is another way of stating Le Châtelier's principle.
D)It is an industrial synthesis of sodium chloride that was discovered by Karl Haber.
E)It is a process for the synthesis of elemental chlorine.

Question 7

At equilibrium, __________.

A)all chemical reactions have ceased
B)the rates of the forward and reverse reactions are equal
C)the rate constants of the forward and reverse reactions are equal
D)the value of the equilibrium constant is 1
E)the limiting reagent has been consumed

Question 8

The equilibrium-constant expression depends on the __________ of the reaction.

A)stoichiometry
B)mechanism
C)stoichiometry and mechanism
D)the quantities of reactants and products initially present
E)temperature

Question 9

The K_eq for the equilibrium below is 0.112 at 700.0°C. SO₂ (g)+ O₂ (g) SO₃ (g)
What is the value of K_eq at this temperature for the following reaction?
2SO₂ (g)+ O₂ (g) 2SO₃ (g)

A)0.224
B)0.335
C)0.0125
D)0.0560
E)0.112

Question 10

The K_eq for the equilibrium below is 5.4 × 10¹³ at 480.0°C. 2NO (g)+ O₂ (g) 2NO₂ (g)
What is the value of K_eq at this temperature for the following reaction?
NO₂ (g) NO (g)+ 1/2 O₂ (g)

A)5.4 × 10^-13
B)5.4 × 10¹³
C)1.4 × 10^-7
D)5.66 × 10^-3
E)none of the above

Question 11

In what year was Fritz Haber awarded the Nobel Prize in chemistry for his development of a process for synthesizing ammonia directly from nitrogen and hydrogen?

A)1954
B)1933
C)1918
D)1900
E)1912

Question 12

Which one of the following will change the value of an equilibrium constant?

A)changing temperature
B)adding other substances that do not react with any of the species involved in the equilibrium
C)varying the initial concentrations of reactants
D)varying the initial concentrations of products
E)changing the volume of the reaction vessel

Question 13

The value of K_eq for the following reaction is 0.25: SO₂ (g)+ NO₂ (g) SO₃ (g)+ NO (g)
The value of K_eq at the same temperature for the reaction below is __________.
2SO₂ (g)+ 2NO₂ (g) 2SO₃ (g)+ 2NO (g)

A)0.50
B)0.063
C)0.12
D)0.25
E)16

Question 14

Which of the following expressions is the correct equilibrium-constant expression for the following reaction? CO₂ (g)+ 2H₂ (g) CH₃OH (g)

A)
B)
C)
D)
E)

Question 15

Which of the following expressions is the correct equilibrium-constant expression for the equilibrium between dinitrogen tetroxide and nitrogen dioxide? N₂O₄ (g) 2NO₂ (g)

A)
B)
C)
D)[NO₂][N₂O₄]
E)[NO₂]²[N₂O₄]

Question 16

Given the following reaction at equilibrium, if K_c = 1.90 × 10¹⁹ at 25.0°C, K_p = __________. H₂ (g)+ Br₂ (g) 2 HBr (g)

A)5.26 × 10^-20
B)1.56 × 10⁴
C)6.44 × 10⁵
D)1.90 × 10¹⁹
E)none of the above

Question 17

The K_eq for the equilibrium below is 0.112 at 700.0°C. SO₂ (g)+ O₂ (g) SO₃ (g)
What is the value of K_eq at this temperature for the following reaction?
SO₃ (g) SO₂ (g)+ O₂ (g)

A)0.224
B)0.0125
C)0.112
D)8.93
E)-0.112

Question 18

The equilibrium constant for reaction 1 is K. The equilibrium constant for reaction 2 is __________. (1)SO₂ (g)+ (1/2)O₂ (g) SO₃ (g)
(2)2SO₃ (g) 2SO₂ (g)+ O₂ (g)

A)K²
B)2K
C)1/2K
D)1/K²
E)-K²

Question 19

The K_eq for the equilibrium below is 0.112 at 700.0°C. SO₂ (g)+ O₂ (g) SO₃ (g)
What is the value of K_eq at this temperature for the following reaction?
2SO₃ (g) 2SO₂ (g)+ O₂ (g)

A)79.7
B)2.99
C)17.86
D)4.46
E)8.93

Question 20

The K_eq for the equilibrium below is 5.4 × 10¹³ at 480.0°C. 2NO (g)+ O₂ (g) 2NO₂ (g)
What is the value of K_eq at this temperature for the following reaction?
4NO (g)+ 2O₂ (g) 4NO₂ (g)

A)5.4 × 10¹³
B)5.4 × 10^-13
C)1.9 × 10¹²
D)1.9 × 10^-12
E)2.9 × 10²⁷

Question 21

Which of the following expressions is the correct equilibrium-constant expression for the reaction below? HF (aq)+ H₂O (l) H₃O⁺ (aq)+ F^- (aq)

A)[HF][H₂O] / [H₃O⁺][F^-]
B)1 / [HF]
C)[H₃O⁺][F^-] / [HF][H₂O]
D)[H₃O⁺][F^-] / [HF]
E)[F^-] / [HF]

Question 22

The equilibrium constant for the gas phase reaction 2SO₂ (g)+ O₂ (g) 2SO₃ (g)
Is K_eq = 2.80 × 10² at 999 K. At equilibrium, __________.

A)products predominate
B)reactants predominate
C)roughly equal amounts of products and reactants are present
D)only products are present
E)only reactants are present

Question 23

Consider the following equilibrium. 2SO₂ (g)+ O₂ (g) 2SO₃ (g)
The equilibrium cannot be established when __________ is/are placed in a 1.0-L container.

A)0.25 mol SO₂ (g)and 0.25 mol O₂ (g)
B)0.75 mol SO₂ (g)
C)0.25 mol of SO₂ (g)and 0.25 mol of SO₃ (g)
D)0.50 mol O₂ (g)and 0.50 mol SO₃ (g)
E)1.0 mol SO₃ (g)

Question 24

Of the following equilibria, only __________ will shift to the right in response to a decrease in volume.

A)H₂ (g)+ Cl₂ (g) 2 HCl (g)
B)2 SO₃ (g) 2 SO₂ (g)+ O₂ (g)
C)N₂ (g)+ 3 H₂ (g) 2 NH₃ (g)
D)2 Fe₂O₃ (s) 4 Fe (s)+ 3 O₂ (g)
E)2HI (g) H₂ (g)+ I₂ (g)

Question 25

Which of the following expressions is the correct equilibrium-constant expression for the reaction below? 2SO₂ (g)+ O₂ (g) 2SO₃ (g)

A)[SO₃] / [SO₂][O₂]
B)[SO₂] / [SO₃]
C)[SO₃]² / [SO₂]²[O₂]
D)[SO₃]² / [SO₂]²[O₂]²
E)[SO₃] / [SO₂][O₂]²

Question 26

For the endothermic reaction CaCO₃ (s) CaO (s)+ CO₂ (g)
Le Châtelier's principle predicts that __________ will result in an increase in the number of moles of CO₂.

A)increasing the temperature
B)decreasing the temperature
C)increasing the pressure
D)removing some of the CaCO₃ (s)
E)none of the above

Question 27

In which of the following reactions would increasing pressure at constant temperature not change the concentrations of reactants and products, based on Le Châtelier's principle?

A)N₂ (g)+ 3H₂ (g) 2NH₃ (g)
B)N₂O₄ (g) 2NO₂ (g)
C)N₂ (g)+ 2O₂ (g) 2NO₂ (g)
D)2N₂ (g)+ O₂ (g) 2N₂O (g)
E)N₂ (g)+ O₂ (g) 2NO (g)

Question 28

Of the following equilibria, only __________ will shift to the left in response to a decrease in volume.

A)H₂ (g)+ Cl₂ (g) 2 HCl (g)
B)2 SO₃ (g) 2 SO₂ (g)+ O₂ (g)
C)N₂ (g)+ 3 H₂ (g) 2 NH₃ (g)
D)4 Fe (s)+ 3 O₂ (g) 2 Fe₂O₃ (s)
E)2HI (g) H₂ (g)+ I₂ (g)

Question 29

How is the reaction quotient used to determine whether a system is at equilibrium?

A)The reaction quotient must be satisfied for equilibrium to be achieved.
B)At equilibrium, the reaction quotient is undefined.
C)The reaction is at equilibrium when Q < K_eq.
D)The reaction is at equilibrium when Q > K_eq.
E)The reaction is at equilibrium when Q = K_eq.

Question 30

At 400 K, the equilibrium constant for the reaction Br₂ (g)+ Cl₂ (g) 2BrCl (g)
Is K_p = 7.0. A closed vessel at 400 K is charged with 1.00 atm of Br₂ (g), 1.00 atm of Cl₂ (g), and 2.00 atm of BrCl (g). Use Q to determine which of the statements below is true.

A)The equilibrium partial pressures of Br₂, Cl₂, and BrCl will be the same as the initial values.
B)The equilibrium partial pressure of Br₂ will be greater than 1.00 atm.
C)At equilibrium, the total pressure in the vessel will be less than the initial total pressure.
D)The equilibrium partial pressure of BrCl (g)will be greater than 2.00 atm.
E)The reaction will go to completion since there are equal amounts of Br₂ and Cl₂.

Question 31

The expression for K_p for the reaction below is __________. 4CuO (s)+ CH₄ (g) CO₂ (g)+ 4Cu (s)+ 2H₂O (g)

A)
B)
C)
D)
E)

Question 32

The equilibrium constant for the gas phase reaction 2NH₃ (g) N₂ (g)+ 3H₂ (g)
Is K_eq = 230 at 300°C. At equilibrium, __________.

A)products predominate
B)reactants predominate
C)roughly equal amounts of products and reactants are present
D)only products are present
E)only reactants are present

Question 33

The equilibrium constant for the gas phase reaction N₂ (g)+ 3H₂ (g) 2NH₃ (g)
Is K_eq = 4.34 × 10^-3 at 300°C. At equilibrium, __________.

A)products predominate
B)reactants predominate
C)roughly equal amounts of products and reactants are present
D)only products are present
E)only reactants are present

Question 34

The equilibrium-constant expression for the reaction Ti (s)+ 2Cl₂ (g) TiCl₄ (l)
Is given by

A)
B)
C)
D)[Cl₂ (g)]^-2
E)

Question 35

Which of the following expressions is the correct equilibrium-constant expression for the reaction below? CO₂ (s)+ H₂O (l) H⁺ (aq)+ HCO₃^- (aq)

A)[H⁺][HCO₃^-] / [CO₂]
B)[CO₂] / [H⁺][HCO₃^-]
C)[H⁺][HCO₃^-] / [CO₂][H₂O]
D)[CO₂][H₂O] / [H⁺][HCO₃^-]
E)[H⁺][HCO₃^-]

Question 36

The equilibrium constant for the gas phase reaction N₂ (g)+ O₂ (g) 2NO (g)
Is K_eq = 4.20 × 10^-31 at 30°C. At equilibrium, __________.

A)products predominate
B)reactants predominate
C)roughly equal amounts of products and reactants are present
D)only products are present
E)only reactants are present

Question 37

Which of the following expressions is the correct equilibrium-constant expression for the reaction below? (NH₄)₂Se (s) 2NH₃ (g)+ H₂Se (g)

A)[NH₃][H₂Se] / [(NH₄)₂Se]
B)[(NH₄)₂Se] / [NH₃]²[H₂Se]
C)1 / [(NH₄)₂Se]
D)[NH₃]²[H₂Se]
E)[NH₃]²[H₂Se] / [(NH₄)₂Se]

Question 38

The reaction below is exothermic: 2SO₂ (g)+ O₂ (g) 2SO₃ (g)
Le Châtelier's Principle predicts that __________ will result in an increase in the number of moles of SO₃ (g)in the reaction container.

A)increasing the pressure
B)decreasing the pressure
C)increasing the temperature
D)removing some oxygen
E)increasing the volume of the container

Question 39

Which of the following statements is true?

A)Q does not change with temperature.
B)K_eq does not change with temperature, whereas Q is temperature dependent.
C)K does not depend on the concentrations or partial pressures of reaction components.
D)Q does not depend on the concentrations or partial pressures of reaction components.
E)Q is the same as K_eq when a reaction is at equilibrium.

Question 40

In which of the following reactions would increasing pressure at constant temperature change the concentrations of reactants and products, based on Le Châteliers principle?

A)N₂ (g)+ 3H₂ (g) 2NH₃ (g)
B)N₂O₄ (g) 2NO₂ (g)
C)N₂ (g)+ 2O₂ (g) 2NO₂ (g)
D)2N₂ (g)+ O₂ (g) 2N₂O (g)
E)all of the above

Question 41

Acetic acid is a weak acid that dissociates into the acetate ion and a proton in aqueous solution: HC₂H₃O₂ (aq) C₂H₃O₂^- (aq)+ H⁺ (aq)
At equilibrium at 25 °C a 0.100 M solution of acetic acid has the following concentrations: [HC₂H₃O₂] = 0.0990 M, [C₂H₃O₂^-] = 1.33 × 10^-3 M, and [H⁺] = 1.33 × 10^-3 M. The equilibrium constant, K_eq, for the ionization of acetic acid at 25°C is __________.

A)5.71 × 10⁴
B)0.100
C)1.75 × 10^-7
D)1.79 × 10^-5
E)5.71 × 10⁶

Question 42

A sealed 1.0 L flask is charged with 0.500 mol of I₂ and 0.500 mol of Br₂. An equilibrium reaction ensues: I₂ (g)+ Br₂ (g) 2IBr (g)
When the container contents achieve equilibrium, the flask contains 0.84 mol of IBr. The value of K_eq is __________.

A)11
B)4.0
C)110
D)6.1
E)2.8

Question 43

Given the following reaction: CO (g)+ 2H₂(g) CH₃OH (g)
In an experiment, 0.42 mol of CO and 0.42 mol of H₂ were placed in a 1.00-L reaction vessel. At equilibrium, there were 0.29 mol of CO remaining. K_eq at the temperature of the experiment is __________.

A)2.80
B)0.357
C)14.5
D)17.5
E)none of the above

Question 44

Consider the following reaction at equilibrium: 2NH₃ (g) N₂ (g)+ 3H₂ (g)ΔH° = +92.4 kJ
Le Châtelier's principle predicts that adding N₂ (g)to the system at equilibrium will result in __________.

A)a decrease in the concentration of NH₃ (g)
B)a decrease in the concentration of H₂ (g)
C)an increase in the value of the equilibrium constant
D)a lower partial pressure of N₂
E)removal of all of the H₂ (g)

Question 45

Consider the following reaction at equilibrium. 2CO₂ (g) 2CO (g)+ O₂ (g)ΔH° = -514 kJ
Le Châtelier's principle predicts that the equilibrium partial pressure of CO (g)can be maximized by carrying out the reaction __________.

A)at high temperature and high pressure
B)at high temperature and low pressure
C)at low temperature and low pressure
D)at low temperature and high pressure
E)in the presence of solid carbon

Question 46

The value of K_eq for the equilibrium H₂ (g)+ I₂ (g) 2 HI (g)
Is 794 at 25 °C. What is the value of K_eq for the equilibrium below?
1/2 H₂ (g)+ 1/2 I₂ (g) HI (g)

A)397
B)0.035
C)28
D)1588
E)0.0013

Question 47

The value of K_eq for the equilibrium CO₂ (g)+ 2H₂ (g) CH₃OH (g)
Is 14.5 at 483 °C. What is the value of K_eq for the equilibrium below?
1/2 CO₂ + H₂ (g) 1/2 CH₃OH (g)

A)7.30
B)7.35
C)0.136
D)3.81
E)6.90 × 10^-2

Question 48

The value of K_eq for the equilibrium H₂ (g)+ I₂ (g) 2 HI (g)
Is 54.0 at 427°C. What is the value of K_eq for the equilibrium below?
HI (g) 1/2 H₂ (g)+ 1/2 I₂ (g)

A)27
B)7.35
C)0.136
D)2.92 × 10³
E)3.43 × 10^-4

Question 49

The equilibrium constant (K_p)for the interconversion of PCl₅ and PCl₃ is 0.0121: PCl₅ (g) PCl₃ (g)+ Cl₂ (g)
A vessel is charged with PCl₅, giving an initial pressure of 0.123 atm. At equilibrium, the partial pressure of PCl₃ is __________ atm.

A)0.0782
B)0.0455
C)0.0908
D)0.0330
E)0.123

Question 50

Consider the following reaction at equilibrium: 2CO₂ (g) 2CO (g)+ O₂ (g)ΔH° = -514 kJ
Le Châtelier's principle predicts that an increase in temperature will __________.

A)increase the partial pressure of O₂ (g)
B)decrease the partial pressure of CO₂ (g)
C)decrease the value of the equilibrium constant
D)increase the value of the equilibrium constant
E)increase the partial pressure of CO

Question 51

A reaction vessel is charged with hydrogen iodide, which partially decomposes to molecular hydrogen and iodine: 2HI (g) H₂(g)+ I₂(g)
When the system comes to equilibrium at 425 °C, P_HI = 0.708 atm, and PH₂ = PI₂ = 0.0960 atm. The value of K_p at this temperature is __________.

A)6.80 × 10^-2
B)1.30 × 10^-2
C)54.3
D)1.84 × 10^-2
E)K_p cannot be calculated for this gas reaction when the volume of the reaction vessel is not given.

Question 52

Consider the following reaction at equilibrium: 2NH₃ (g) N₂ (g)+ 3H₂ (g)
Le Châtelier's principle predicts that the moles of H₂ in the reaction container will increase with __________.

A)some removal of NH₃ from the reaction vessel (V and T constant)
B)a decrease in the total pressure (T constant)
C)addition of some N₂ to the reaction vessel (V and T constant)
D)a decrease in the total volume of the reaction vessel (T constant)
E)an increase in total pressure by the addition of helium gas (V and T constant)

Question 53

The effect of a catalyst on an equilibrium is to __________.

A)increase the rate of the forward reaction only
B)increase the equilibrium constant so that products are favored
C)slow the reverse reaction only
D)increase the rate at which equilibrium is achieved without changing the composition of the equilibrium mixture
E)shift the equilibrium to the right

Question 54

Consider the following reaction at equilibrium: 2CO₂ (g) 2CO (g)+ O₂ (g)ΔH° = -514 kJ
Le Châtelier's principle predicts that adding O₂ (g)to the reaction container will __________.

A)increase the partial pressure of CO (g)at equilibrium
B)decrease the partial pressure of CO₂ (g)at equilibrium
C)increase the value of the equilibrium constant
D)increase the partial pressure of CO₂ (g)at equilibrium
E)decrease the value of the equilibrium constant

Question 55

Consider the following chemical reaction: CO (g)+ 2H₂ (g) CH₃OH(g)
At equilibrium in a particular experiment, the concentrations of CO and H₂ were 0.15 M and0.36 M,respectively. What is the equilibrium concentration of CH₃OH? The value of K_eq for this reaction is 14.5 at the temperature of the experiment.

A)14.5
B)7.61 × 10^-3
C)2.82 × 10^-1
D)3.72 × 10^-3
E)1.34 × 10^-3

Question 56

The value of K_eq for the equilibrium N₂ (g)+ O₂ (g) 2 NO (g)
Is 4.2 × 10^-31 at 27 °C. What is the value of K_eq for the equilibrium below?
4 NO (g) 2 N₂ (g)+ 2 O₂ (g)

A)5.7 × 10⁶⁰
B)8.4 × 10^-31
C)4.2 × 10³¹
D)8.4 × 10³¹
E)none of the above

Question 57

Dinitrogentetraoxide partially decomposes according to the following equilibrium: N₂O₄ (g) 2NO₂ (g)
A 1.00-L flask is charged with 0.0400 mol of N₂O₄. At equilibrium at 373 K, 0.0055 mol of N₂O₄ remains. K_eq for this reaction is __________.

A)2.2 × 10^-4
B)13
C)0.22
D)0.022
E)0.87

Question 58

Consider the following reaction at equilibrium: 2SO₂ (g)+ O₂ (g) 2SO₃ (g)ΔH° = -99 kJ
Le Châtelier's principle predicts that an increase in temperature will result in __________.

A)a decrease in the partial pressure of SO₃
B)a decrease in the partial pressure of SO₂
C)an increase in K_eq
D)no changes in equilibrium partial pressures
E)the partial pressure of O₂ will decrease

Question 59

Consider the following reaction at equilibrium: C (s)+ H₂O (g) CO (g)+ H₂ (g)
Which of the following conditions will increase the partial pressure of CO?

A)decreasing the partial pressure of H₂O (g)
B)removing H₂O (g)from the system
C)decreasing the volume of the reaction vessel
D)decreasing the pressure in the reaction vessel
E)increasing the amount of carbon in the system

Question 60

The value of K_eq for the equilibrium H₂ (g)+ I₂ (g) 2 HI (g)
Is 794 at 25°C. At this temperature, what is the value of K_eq for the equilibrium below?
HI (g) 1/2 H₂ (g)+ 1/2 I₂ (g)

A)1588
B)28
C)397
D)0.035
E)0.0013

Question 61

Given the following reaction at equilibrium at 300.0 K: NH₄HS (s) NH₃ (g)+ H₂S (g)
If pNH₃ = pH₂S = 0.109 atm, K_p = __________.

A).0119
B)4.99 × 10^-4
C).109
D).0821
E)5.66 × 10^-3

Question 62

Given the following reaction at equilibrium, if K_p = 0.990 at 250.0°C, K_c = __________. PCl₅ (g) PCl₃ (g)+ Cl₂ (g)

A)3.90 × 10^-6
B)2.31 × 10^-2
C)0.990
D)42.9
E)42.5

Question 63

Consider the following chemical reaction: H₂ (g)+ I₂ (g) 2HI (g)
At equilibrium in a particular experiment, the concentrations of H₂, I₂, and HI were 0.25 M, 0.035 M, and 0.55 M, respectively. The value of K_eq for this reaction is __________.

A)23
B)63
C)0.0090
D)5.1
E)34

Question 64

At elevated temperatures, molecular hydrogen and molecular bromine react to partially form hydrogen bromide: H₂ (g)+ Br₂ (g) 2HBr (g)
A mixture of 0.682 mol of H₂ and 0.440 mol of Br₂ is combined in a reaction vessel with a volume of 2.00 L. At equilibrium at 700 K, there are 0.556 mol of H₂ present. At equilibrium, there are __________ mol of Br₂ present in the reaction vessel.

A)0.000
B)0.440
C)0.556
D)0.126
E)0.314

Question 65

At 27°C, K_p = 0.095 for the equilibrium: NH₄HS (s) NH₃ (g)+ H₂S (g)
A sample of solid NH₄HS is placed in a closed vessel and allowed to equilibrate. Calculate the equilibrium partial pressure (atm)of ammonia, assuming that some solid NH₄HS remains.

A)0.31
B)0.095
C)0.052
D)0.0049
E)3.8

Question 66

At 1000.0 K, the equilibrium constant for the reaction 2NO (g)+ Br₂ (g) 2NOBr (g)
Is K_p = 0.017. Calculate K_p for the reverse reaction,
2NOBr (g) 2NO (g)+ Br₂ (g).

A)0.017
B)1.6 × 10^-4
C)59
D)0.99
E)1.1

Question 67

Given the following reaction at equilibrium at 450.0°C: CaCO₃ (s) CaO (s)+ CO₂ (g)
If pCO₂ = 0.0135 atm, K_c = __________.

A)135
B)0.0821
C)0.801
D)2.27 × 10^-4
E)8.01

Question 68

Nitrosyl bromide decomposes according to the following equation. 2NOBr (g) 2NO (g)+ Br₂ (g)
A sample of NOBr (0.64 mol)was placed in a 1.00-L flask containing no NO or Br₂. At equilibrium the flask contained 0.36 mol of NOBr. How many moles of NO and Br₂, respectively, are in the flask at equilibrium?

A).28,.28
B).36,.18
C).28,.14
D).14,.23
E).36,.36

Question 69

K_p = 0.0198 at 721 K for the reaction 2HI (g) H₂ (g)+ I₂ (g)
In a particular experiment, the partial pressures of H₂ and I₂ at equilibrium are 0.836 and 0.701 atm, respectively. The partial pressure of HI is __________ atm.

A)7.87
B)29.6
C)5.44
D)0.108
E)0.0116

Question 70

The equilibrium-constant expression for a reaction written in one direction is the __________ of the one for the reaction written for the reverse direction.

Question 71

In the coal-gasification process, carbon monoxide is converted to carbon dioxide via the following reaction: CO (g)+ H₂O (g) CO₂ (g)+ H₂ (g)
In an experiment, 0.35 mol of CO and 0.40 mol of H₂O were placed in a 1.00-L reaction vessel. At equilibrium, there were 0.16 mol of CO remaining. K_eq at the temperature of the experiment is __________.

A)5.5
B)0.75
C)0.93
D)1.1
E)1.0

Question 72

Phosphorous trichloride and phosphorous pentachloride equilibrate in the presence of molecular chlorine according to the reaction: PCl₃ (g)+ Cl₂ (g) PCl₅ (g)
An equilibrium mixture at 450 K contains
PPCl₃ = 0.124 atm,
PCl₂ = 0.157 atm, and
PPCl₅ = 1.30 atm. What is the value of K_p at this temperature?

A)66.7
B)1.50 × 10^-2
C)2.53 × 10^-2
D)1.02
E)4.63

Question 73

At 200°C, the equilibrium constant (K_p)for the reaction below is 2.40 × 10³. 2NO (g) N₂ (g)+ O₂ (g)
A closed vessel is charged with 36.1 atm of NO. At equilibrium, the partial pressure of O₂ is __________ atm.

A)294
B)35.7
C)17.9
D)6.00
E)1.50 × 10^-2

Question 74

At 900.0 K, the equilibrium constant (K_p)for the following reaction is 0.345. 2SO₂ + O₂ (g) 2SO₃ (g)
At equilibrium, the partial pressure of SO₂ is 35.0 atm and that of O₂ is 15.9 atm. The partial pressure of SO₃ is __________ atm.

A)82.0
B)4.21 × 10^-3
C)192
D)6.20 × 10^-4
E)40.2

Question 75

Given the following reaction at equilibrium, if K_c = 6.34 x 10⁵ at 230.0°C, K_p = __________. 2NO (g)+ O₂ (g) 2NO₂ (g)

A)3.67 × 10^-2
B)1.53 × 10⁴
C)6.44 × 10⁵
D)2.61 × 10⁶
E)2.62 × 10⁷

Question 76

The K_p for the reaction below is 1.49 × 10⁸ at 100.0°C: CO (g)+ Cl₂ (g) COCl₂ (g)
In an equilibrium mixture of the three gases, PCO = PCl₂ = 2.22 × 10^-4 atm. The partial pressure of the product, phosgene (COCl₂), is __________ atm.

A)7.34
B)3.02 × 10¹⁵
C)3.31 × 10^-16
D)3.31 × 10⁴
E)6.67 × 10¹¹

Question 77

The K_eq for the equilibrium below is 7.73 × 10^-2 at 500.0°C. 2Cl₂ (g)+ 2H₂O (g) 4HCl (g)+ O₂ (g)
What is the value of K_eq at this temperature for the following reaction?
Cl₂ (g)+ H₂O (g) 2HCl (g)+ O₂ (g)

A)0.0773
B)5.98 × 10^-3
C)0.278
D)0.0376
E)0.150

Question 78

If the value for the equilibrium constant is much greater than 1, then the equilibrium mixture contains mostly __________.

Question 79

Dinitrogen tetroxide partially decomposes according to the following equilibrium: N₂O₄ (g) 2NO₂ (g)
A 1.000-L flask is charged with 3.00 × 10^-2 mol of N₂O₄. At equilibrium, 2.36 × 10^-2 mol of N₂O₄ remains. K_eq for this reaction is __________.

A)0.723
B)0.391
C)0.212
D)6.94 × 10^-3
E)1.92 × 10^-4

Question 80

If Reaction A + Reaction B = Reaction C, then K_c Reaction C = __________.