Deck 14: Chemical Equilibrium: How Much Product Does a Reaction Really Make

Question 1

The forward rate constant, k_f, and reverse rate constant, k_r, for a chemical reaction are not equal. Which of the following must be true?

A)The reaction will be unable to achieve equilibrium.
B)k_f and k_r will become equal as equilibrium is approached, owing to concentration changes.
C)k_f and k_r will become equal as equilibrium is approached, owing to temperature changes.
D)k_f and k_r will remain unequal but the rates will become equal, owing to concentration changes.
E)k_f and k_r will remain unequal but the rates will become equal, owing to temperature changes.

Answer 1

k_f and k_r will remain unequal but the rates will become equal, owing to concentration changes.

Question 2

A chemical equilibrium 2 A B
Has a forward rate constant, k_f  10 M ^1s^1, and a reverse rate constant, k_r  5.0 s^1. What is the value of the equilibrium constant for this system?

A)0.5
B)2.0
C)20
D)0.050
E)5.0

Answer 2

2.0

Question 3

For an equilibrium reaction with K  4.3  10^3, the reverse rate constant was found to be 2.1  10². What is the value of the forward rate constant?

A)2.0  10^5
B)3.1  10^3
C)9.0  10^1
D)4.9  10⁴
E)5.3  10³

Answer 3

9.0  10^1

Question 4

A chemical equilibrium 2 A B
Has a forward rate constant, k_f  10 M ^1 s^1, and a reverse rate constant, k_r  5 s^1. If the system has a concentration of [A]  0.10 M at equilibrium, what must be the concentration of B at equilibrium?

A)20.0
B)2.0
C)0.20
D)0.020
E)200

Question 5

A chemical equilibrium may be established by starting a reaction with ________

A)reactants only.
B)products only.
C)equal quantities of reactants and products.
D)any quantities of reactants and products.
E)all of the above.

Question 6

Which expression corresponds to the equilibrium constant for the reaction written as 2H₂(g)  O₂(g) 2H₂O₂(g)?

A)[H₂]²[O₂]
B)
C)
D)
E)

Question 7

Which statement about a chemical reaction is not correct?

A)All chemical reactions are reversible since products can be converted back into the reactants.
B)If a reaction is characterized as lying far to the left, then the concentration of products is small when equilibrium is reached.
C)At equilibrium, the rates of the forward reaction and reverse reaction are equal.
D)At equilibrium, the rates of the forward and reverse reactions are equal because both have stopped.
E)Chemical equilibrium is said to be "a dynamic process."

Question 8

In a reversible reaction A B at a particular temperature, the rate constant for the reverse reaction is twice the rate constant for the forward reaction. At equilibrium, how are the concentrations of A and B related?

A)Can't tell, need more information.
B)[A]  [B]
C)[A]  2  [B]
D)[A]   [B]
E)[A]  4  [B]

Question 9

Write the equilibrium expression for the reaction

A)
B)
C)
D)
E)

Question 10

A chemical equilibrium A 3B
Has a forward rate constant, s^1  5 M ^1s^1, and a reverse rate constant, M ^2s^1  0.5 s^1. What is the value of the equilibrium constant for this system?

A)0.1
B)0.5
C)5.0
D)10
E)15

Question 11

The law of mass action is a result of ________

A)the law of conservation of matter.
B)the law of conservation of energy.
C)kinetics of reversible reactions.
D)limiting reactant stoichiometry.
E)the third law of thermodynamics.

Question 12

Which of the following can be predicted from the law of mass action?
I. At equilibrium, the ratio of concentrations of products to reactants, each raised to a power corresponding to the stoichiometric coefficient in the balanced reaction equation, will have a constant value at a given temperature.
II. The direction of the reaction given values for the reactant and product concentrations and the equilibrium constant.
III. The amounts of products that can be produced from a given amount of reactants.

A)I only
B)II and III
C)I, II, and III
D)I and II
E)I and III

Question 13

Which of the following is true for a chemical reaction at equilibrium regarding the concentration of products?

A)They will not change because there are no more reactants.
B)They will not change because the limiting reagent is gone.
C)They will not change because this is a constant for each reaction.
D)They will not change because the forward and reverse rates are equal.
E)They will change continually because of reversibility.

Question 14

For an equilibrium reaction with K  1.2  10⁸, the forward rate constant was found to be 3.5  10⁵. What is the value of the reverse rate constant?

A)3.5  10⁵
B)3.4  10²
C)4.2  10¹³
D)2.9  10^3
E)6.0  10^5

Question 15

Which of the following is true for a chemical reaction at equilibrium?

A)Only the forward reaction stops.
B)Only the reverse reaction stops.
C)Both the forward and reverse reactions stop.
D)The rate constants for the forward and reverse reactions are equal.
E)The rates of the forward and reverse reactions are equal.

Question 16

Which of the following is true for a chemical reaction at equilibrium?

A)All reaction has ceased.
B)The reaction has gone to completion to products.
C)The amount of reactant(s) remaining is always equal to the amount of product(s) formed.
D)The rates of the forward and reverse reactions are equal.
E)The concentrations of products and reactants are still changing.

Question 17

Which of A-D is equal in an equilibrium?

A)the concentrations of reactants and products
B)the rate constants for the forward and reverse reactions
C)the time that a particular atom or molecule spends as a reactant and product
D)the rate of the forward and reverse reaction
E)All of the above are equal.

Question 18

In a reversible reaction A B at a particular temperature, the rate constant for the reverse reaction is 4 times the rate constant for the forward reaction. What is the value of the equilibrium constant at that temperature?

A)Can't tell, need more information.
B)0.25
C)4
D)16
E)0.5

Question 19

Consider the equilibrium A  B C. What is significant about the equilibrium state in which [B]  [C]?

A)[A]  K
B)[A]  [B]  [C]
C)[B]  [C]  K
D)[A]  1/K
E)[C]/[B]  K

Question 20

At a high temperature, carbon dioxide decomposes to produce carbon monoxide and oxygen. Which expression corresponds to the equilibrium constant for the reaction written as

A)
B)
C)
D)
E)

Question 21

Calculate K for the following reaction, provided the concentration versus time graph shown below. 2A 2B  3C

A)0.50
B)0.68
C)1.1
D)1.5
E)2.8

Question 22

An equilibrium that strongly favors products has ________

A)a value of K  1.
B)a value of K  1.
C)a value of Q  1.
D)a value of Q  1.
E)K  Q.

Question 23

A decrease in the number of moles of gas as the reaction goes from reactants to products in a gas-phase equilibrium results in ________

A)K_p  K_c.
B)K_p  K_c.
C)K_p  K_c.
D)K_p  K_c  (RT ) .
E)K_pK_c  (RT ) .

Question 24

Under what conditions are the values of K_c and K_p for a given gas-phase equilibrium the same?

A)if there is no change in the moles of gas in the reaction
B)if there is no change in the temperature during the reaction
C)if the coefficients of the reactants and products are the same
D)if the pressure remains constant
E)if either K_c or K_p  1

Question 25

Two students measured an equilibrium constant for the same chemical reaction. Ken obtained a value of 130 for the equilibrium constant, but Barbie obtained a value of 11.4. The instructor checked their results and said they were both correct. How can that be?

A)The values vary according to the way the measurement is made.Ken must have measured product concentrations, while Barbie measured reactant concentrations.
B)The values vary according to the starting conditions of the reaction prior to equilibrium.Ken must have started with all reactants, while Barbie must have started with all products.
C)The values vary according to the stoichiometric coefficients that are used.The balancing coefficients that Ken used must have been twice those that Barbie used.
D)The values vary according to direction of the reaction.Ken must have used the reverse reaction.
E)The instructor must have made a mistake, because the equilibrium constant for a reaction must always be the same.

Question 26

The equilibrium constant for the formation of hydrogen iodide from hydrogen and iodine is 45.0 at a certain temperature. H₂(g)  I₂(s) 2 HI(g)
Which of the following is true regarding this equilibrium?
I.The reaction is product-favored.
II.The reaction is reactant-favored.
III.Equilibrium lies to the right.
IV.Equilibrium lies to the left.

A)I and III
B)I and IV
C)II and III
D)II and IV
E)None are true, as the concentrations of reactants and products are essentially the same.

Question 27

For the following reaction, K_c = 0.500 at 300K. What is the value of K_p? 2A(g) B(g) 2C(g)  D(g)

A)8.2610^4
B)2.0310^2
C)0.500
D)12.3
E)303

Question 28

Water can decompose at an elevated temperature to give hydrogen and oxygen according to the equation below. At a particular temperature, the partial pressures of H₂O, H₂, and O₂ are 0.055 atm, 0.0065 atm, and 0.0045 atm, respectively, at equilibrium. What is the value of the equilibrium constant, K_P, for this reaction at this temperature? 2H₂O(g) 2H₂(g)  O₂(g)

A)5.3  10^4
B)3.5  10^6
C)6.3  10^5
D)1.6  10⁴
E)3.0  10⁴

Question 29

Sulfur dioxide, gaseous water, and oxygen gas react to prepare sulfuric acid in the following unbalanced equation. Under equilibrium conditions, the partial pressures of the components are P_SO2  0.1 atm, P_H2O  0.05 atm, P_O2  0.25 atm, P_H2SO4  2.75 atm.
What is the value of the equilibrium constant, K_p, for the reaction?

A)3.30  10^4
B)5.0010^4
C)2.2010³
D)3.0310³
E)1.2110⁶

Question 30

For the following hypothetical equilibrium, what is the value of the equilibrium constant if the concentrations at equilibrium are as shown? A  2 B C
[A]  4.5  10^5 M
[B]  2.2  10^2 M
[C]  9.4  10^3 M

A)0.22
B)9.9
C)4.3  10⁵
D)2.3  10⁸
E)9.5  10³

Question 31

Equilibrium constants can be expressed in terms of molar concentration, K_c, or partial pressure, K_P. To relate these two equilibrium constants to each other, ________

A)each concentration must be multiplied by the factor RT.
B)each pressure must be multiplied by the factor RT.
C)K_c must be multiplied by the factor RT.
D)K_P must be multiplied by the factor RT.
E)nothing must be done because their values are equal.

Question 32

Coal (C) can be heated with steam (H₂O) at high temperatures to produce a mixture of hydrogen and carbon monoxide gases. Methanol, which is a useful fuel, can be produced from these gases by the reaction below. At a particular high temperature, the equilibrium concentrations are the following: [H₂]  0.095 mol/L, [CO]  0.035 mol/L, and [CH₃OH]  0.065 mol/L. What is the value of the equilibrium constant, K_c, for this reaction at this temperature?
2H₂(g)  CO(g) CH₃OH(g)

A)4.70
B)290
C)206
D)19.5
E)4.86

Question 33

Calculate K for the following reaction, provided the concentration versus time graph shown below. 3A B  2C

A)2.0
B)10
C)22
D)31
E)44

Question 34

Equilibrium constants for gases can be expressed in terms of concentrations, K_c, or in terms of partial pressures, K_p. Which one of the following statements regarding K_c and K_p is correct?

A)K_c and K_p are equal when all stoichiometric coefficients in the balanced reaction equation equal one.
B)K_c and K_p have the same values but different units.
C)K_c and K_p are equal when the sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants.
D)K_c and K_p can never be equal.
E)K_c and K_p are equal when the conditions are standard (P  1 atm, T  298 K).

Question 35

Which expression corresponds to the equilibrium constant K_c for the reaction written as 2NH₃(g)  2O₂(g) N₂O(g)  3H₂O₂(g)

A)
B)
C)
D)[N₂O][H₂O₂]³
E)

Question 36

The chemical equilibrium constant for the following reaction is 2.15  10². 2NO₂(g) N₂O₄(g)
What is the value of the equilibrium constant for the following reaction?
6NO₂(g) 3N₂O₄(g)

A)6.45  10²
B)9.94  10⁶
C)1.01  10^7
D)1.55  10^3
E)4.65  10^2

Question 37

An increase in the number of moles of gas as the reaction goes from reactants to products in a gas-phase equilibrium results in ________

A)K_p  K_c.
B)K_p  K_c.
C)K_p  K_c.
D)K_p  K_c  (RT ) .
E)K_pK_c  (RT ) .

Question 38

The equilibrium constant for the acid ionization of mercaptoethanol (HSCH₂CH₂OH ) is 1.91  10^10_. HSCH₂CH₂OH(aq) H^(aq)  SCH₂CH₂OH^(aq)
Which of the following is true regarding this equilibrium?
I.The reaction is product-favored.
II.The reaction is reactant-favored.
III.Equilibrium lies far to the right.
IV.Equilibrium lies far to the left.

A)I and III
B)I and IV
C)II and III
D)II and IV
E)None are true, as the concentrations of reactants and products are comparable.

Question 39

The equilibrium constant for the formation of calcium carbonate from the ions in solution is 2.2  10⁸ according to the reaction: What is the value of the equilibrium constant for the reverse of this reaction?

A)the same, 2.2  10⁸
B)(2.2  10⁸)
C)2.2  10^8
D)4.5  10^9
E)4.5  10⁹

Question 40

For the following reaction, K_p = 137 at 3.50 10²K. What is the value of K_c? 2C₄H₁₀(l)  3O₂(g) 8CO₂(g)  10H₂O(g)

A)7.0310^6
B)5.7910^3
C)4.77
D)3.2410⁶
E)2.6710⁹

Question 41

In the following reaction, which of the statements is true, given the concentrations of each species? N₂(g)  3 H₂(g) 2 NH₃(g) K  9.60
[N₂]  [H₂]  0.100 M and [NH₃]  0.352 M

A)The reaction is at equilibrium.
B)More ammonia must form to achieve equilibrium.
C)More nitrogen and hydrogen must form to achieve equilibrium.
D)More nitrogen must be consumed to achieve equilibrium.
E)Equilibrium cannot be established in the system.

Question 42

Given the following reactions and associated equilibrium constants K₁  3.1 K₂  4.5 what is the equilibrium constant for the following reaction?
SO₃(g)  NO(g) SO₂(g)  NO₂(g) K_new  ?

A)1.45
B)7.17  10^-2
C)14.0
D)6.89  10^-1
E)163

Question 43

If the reaction quotient Q has a smaller value than the related equilibrium constant, K, ________

A)the reaction is at equilibrium.
B)the reaction will continue to make more products.
C)the reaction will consume products and make reactants.
D)the reaction will release heat to achieve equilibrium.
E)the value of K will decrease until it is equal to Q.

Question 44

The equilibrium constants for the two reactions are known: M^m 4L^ [ML₄]^m4 K_a
HL H^ L^ K_b
What must be the value of the equilibrium constant, K_overall for the following overall reaction?
M^m  4HL [ML₄]^m4  4H^ K_overall

A)K_aK_b
B)K_a  4K_b
C)K_a  K_b⁴
D)K_aK_b⁴
E)K_aK_b^1/4

Question 45

The chemical equilibrium constant for the following reaction is 14.5. CH₃OH(g) CO(g)  2H₂(g)
What is the value of the equilibrium constant for the following reaction?

A)3.81
B)2.62  10^1
C)7.25
D)1.38  10^1
E)6.90  10^2

Question 46

Which of the following is the equilibrium expression for the scrubbing reaction of calcium oxide and sulfur dioxide to remove sulfur dioxide from the exhaust gases of coal-fired power plants? CaO(s)  SO₂(g) CaSO₃(s)

A)K_c  [SO₂]
B)K_c 
C)K_c  [CaO]  [SO₂]
D)K_c 
E)K_c  [CaSO₃]  [CaO]  [SO₂]

Question 47

Given the following reactions and associated equilibrium constants 2NO(g) K₁  1.70  10^13 NO₂(g)
K₂  6.83  10⁶
What is the equilibrium constant for the following reaction?
2N₂O(g)  3O₂(g) 4NO₂(g) K_new  ?

A)1.59  10^2
B)9.29  10^18
C)40.3
D)62.9
E)1.08  10¹⁷

Question 48

Sulfur dioxide emitted in the burning of coal is "scrubbed" from the effluent using ________

A)limestone (CaCO₃).
B)lime (CaO).
C)calcium metal (Ca).
D)calcium hydride (CaH₂).
E)calcium hydroxide [Ca(OH)₂].

Question 49

Write the expression for the reaction quotient for the reaction Cu^2(aq)  4NH₃(aq) Cu(NH₃)₄^2(aq)

A)Q = [Cu^2]  4[NH₃]  [Cu(NH₃)₄^2]
B)
C)
D)
E)

Question 50

Which statement about an equilibrium constant, K, and a reaction quotient, Q, for a reaction is correct?

A)Values for each can be determined using units of moles/liter or atmospheres.
B)K is the reciprocal of Q: K  1/Q.
C)K always is larger than Q.
D)Q always is larger than K.
E)Q can never equal K.

Question 51

If the reaction quotient Q is equal to the related equilibrium constant, K, ________

A)the reaction is at equilibrium.
B)the reaction will continue to make more products.
C)the reaction will consume products and make reactants.
D)the reaction will release heat to achieve equilibrium.
E)the value of K will increase until it is equal to Q.

Question 52

The equilibrium constant for the reaction below is 1.310^2. What is the value of the equilibrium constant for the following reaction?

A)1.69  10^4
B)1.30  10^2
C)1.14  10^1
D)8.77
E)76.9

Question 53

A series of four equilibrium steps can be defined for the following overall reaction: Cu^2  4NH₃ [Cu(NH₃)₄]^2K_overall
Cu^2  NH₃ [Cu(NH₃)]^2K₁
[Cu(NH₃)]^2  NH₃ [Cu(NH₃)₂]^2K₂
Etc)
What is true about K₄?

A)K₄  K_overall
B)K₄  K₁K₂K₃
C)
D)
E)

Question 54

In equilibrium expressions, the concentrations of pure solids and liquids ________

A)have the assigned value of one.
B)have the assigned value of zero.
C)have constant values, c_S and c_l.
D)are determined from the density and molar mass.
E)are treated as any other solute.

Question 55

Which one of the following is the equilibrium expression, K_P, for the reaction that produces lime, CaO, from limestone, CaCO₃? CaCO₃(s) CaO(s)  CO₂(g)

A)
B)
C)
D)[CaO][CO₂]
E)

Question 56

The equilibrium constant for the reaction below is 17.5. S(s)  3 O₂(g) 2 SO₃(g)
What is the value of the equilibrium constant for the following reaction?
6 SO₃(g) 3S(s)  9 O₂(g)

A)1.87  10^4
B)5.71  10^2
C)17.5
D)306
E)5360

Question 57

In the following reaction, which of the statements is true, given the concentrations of each species? C₆H₆(g)  3H₂(g) C₆H₁₂(g) K  1.2310^3
[C₆H₆]  [H₂]  0.170 M and [C₆H₁₂]  0.025 M

A)More hydrogen must be consumed to achieve equilibrium.
B)More cyclohexane (C₆H₁₂) must form to achieve equilibrium.
C)The reaction is at equilibrium.
D)More benzene (C₆H₆) must be formed to achieve equilibrium.
E)Equilibrium cannot be established in the system.

Question 58

Gaseous hydrogen and iodine can be used to prepare HI in the following balanced chemical reaction. Calculate a value for the reaction quotient when [H₂]  [I₂]  4.67 10^-3 M and [HI]  4.07  10^-2 M. H₂(g)  I₂(g) 2HI(g)

A)1.32  10^2
B)1.87  10³
C)76.0
D)5.36  10^4
E)1.77  10^1

Question 59

Water can decompose at an elevated temperature to give hydrogen and oxygen according to the equation below. At a particular temperature in a vessel containing water vapor and air, the partial pressures of H₂O, H₂, and O₂ are 0.055 atm, 0.0065 atm, and 0.19 atm, respectively. What is the value of the reaction quotient, Q_P, for this reaction under these conditions? 2H₂O(g) 2H₂(g)  O₂(g)

A)0.023
B)1.5  10^4
C)2.7  10^3
D)370
E)4.4  10⁴

Question 60

If the reaction quotient Q has a larger value than the related equilibrium constant, K, ________

A)the reaction is at equilibrium.
B)the reaction will continue to make more products.
C)the reaction will consume products and make reactants.
D)the reaction will release heat to achieve equilibrium.
E)the value of K will increase until it is equal to Q.

Question 61

Which of the following reactions will not shift toward the reactants products when the pressure of the system is altered by changing the volume?

A)2CO₂(g) 2 CO(g)  O₂(g)
B)CaCO₃(s) CaO(s)  CO₂(g)
C)N₂(g)  3H₂(g) 2NH₃(g)
D)H₂(g)  I₂(g) 2HI(g)
E)2SO₂(g)  O₂(g) 2SO₃(g)

Question 62

In a simple equilibrium A  B C, will there be any stress to the system if both B and C are added to the equilibrium system simultaneously and in the same amount?

A)No, these two stresses will always cancel each other out.
B)No, these two stresses will cancel each other out unless the initial concentrations of B and C are also the same.
C)Yes, the same amount of A is also required for the stresses to cancel each other out.
D)Yes, unless the initial concentrations of B and C are also the same.
E)More than two of the above statements are correct.

Question 63

Cylinders of NO gas may contain small quantities of oxygen as an impurity, leading to the formation of NO₂ in equilibrium with the NO and the oxygen. Is this contamination by NO₂ dependent on the pressure in the tank?

A)Yes, there will be more NO₂ at higher pressures.
B)Yes, there will be less NO₂ at higher pressures.
C)No, the amount of NO₂ has nothing to do with pressure.
D)No, the amount of NO₂ depends on the partial pressure, not the total pressure.
E)There is no way to tell without additional information.

Question 64

Which of the following occurs when products are removed from a chemical reaction in solution or the gas phase at equilibrium?

A)Q increases and the equilibrium shifts to produce more products.
B)Q increases and the equilibrium shifts to produce more reactants.
C)Q decreases and the equilibrium shifts to produce more products.
D)Q decreases and the equilibrium shifts to produce more reactants.
E)Q is unchanged by the removal of products.

Question 65

If the temperature of an endothermic reaction at equilibrium could be increased instantaneously, what would be the instantaneous effect on Q and K before equilibrium was again achieved?

A)Q would increase and K would stay the same.
B)Q would decrease and K would stay the same.
C)Q would stay the same and K would increase.
D)Q would stay the same and K would decrease.
E)Both Q and K would stay the same.

Question 66

Given the reaction below, which of the following would cause an increase in the concentration of products? 4NH₃(g)  3O₂(g) 2N₂(g)  6H₂O(g)
I. addition of water
II. removal of ammonia
III. decrease of the volume of the container
IV. addition of oxygen

A)I only
B)II only
C)IV only
D)II and III
E)III and IV

Question 67

Given the reaction below, which of the following would cause an increase in the concentration of reactants? 2HF(g) F₂(g)  H₂(g) H^° 12.0 kJ/mol
I. removal of hydrogen
II. addition of HF
III. increasing the temperature of the reaction
IV. an increase in the volume of the container

A)I only
B)II only
C)III only
D)IV only
E)III and IV

Question 68

Carbon dioxide and argon, which is a noble or inert gas, are placed in a vessel and heated. Equilibrium is reached at some particular temperature. Carbon dioxide dissociates by the following reaction. 2CO₂(g) 2CO(g)  O₂(g)
What is the result of increasing the pressure by adding more argon?
I. The equilibrium shifts to produce more carbon dioxide and reduce the pressure.
II. The equilibrium shifts to remove carbon dioxide and reduce the pressure.
III. The equilibrium does not change because argon is not involved in the reaction.
IV. The equilibrium does not change because the concentrations are not affected.

A)I only
B)II only
C)III only
D)IV only
E)III and IV

Question 69

What happens to the equilibrium between NO₂(g) and N₂O₄(g) in inert argon when the volume is increased and additional argon is added to maintain a constant total pressure?

A)The ratio of NO₂ to N₂O₄ increases solely because of the increase in volume.
B)The ratio of NO₂ to N₂O₄ increases solely because of the addition of argon.
C)The ratio of NO₂ to N₂O₄ decreases solely because of the increase in volume.
D)The ratio of NO₂ to N₂O₄ decreases solely because of the addition of argon.
E)The ratio of NO₂ to N₂O₄ remains the same, because the effects of the two processes cancel each other out.

Question 70

In the Reaction, Initial, Change, Equilibrium (RICE) table started for calculating equilibrium concentrations of the reaction shown, the terms in the "change" row are ________

A)(x, x, x.)
B)(x, x, x.)
C)(x, 4x, x.)
D)(x, 4x, x.)
E)(x, 4x, x.)

Question 71

Solid mercury(II) oxide decomposes when heated to produce liquid mercury and oxygen. 2HgO(s) 2Hg(l)  O₂(g)
An amount of mercury(II) oxide is placed in a vessel at a particular temperature and allowed to reach equilibrium. How could the amount of liquid mercury in the vessel be increased?
I. adding more mercury(II) oxide
II. removing some oxygen
III. increasing the volume of the vessel

A)I only
B)II only
C)III only
D)I and II
E)II and III

Question 72

Which of the following is true regarding the effect of a catalyst on chemical equilibrium?

A)Only the forward rate increases, so the quantity of products increases.
B)Only the forward rate increases, but the quantity of products remains the same.
C)Both the forward and reverse rates increase, and the quantity of products increases.
D)Both the forward and reverse rates increase, but the quantity of products is unchanged.
E)The effect varies depending on whether the reaction is endothermic or exothermic.

Question 73

For a chemical reaction at equilibrium, which of the following will change the value of the equilibrium constant K?
I.changing the temperature
II.changing the total concentration of reactants and products
III.changing the reaction coefficients

A)I only
B)II only
C)III only
D)I and II only
E)I and III only

Question 74

Addition of reactants to a chemical reaction in solution or gas phase at equilibrium results in ________

A)an increase in K and a shift in equilibrium to produce more products.
B)an increase in K and a shift in equilibrium to produce more reactants.
C)a decrease in K and a shift in equilibrium to produce more products.
D)a decrease in K and a shift in equilibrium to produce more reactants.
E)no change in K and a shift in equilibrium to produce more products.

Question 75

Identify whether or not perturbations A-D will affect the equilibrium concentrations of reactants and products in a gas-phase endothermic chemical reaction that involves one or more gases. If all have an effect on the equilibrium concentrations, select response E. Otherwise, identify the one that does not affect the equilibrium concentrations.

A)adding reactants to a gas or solution reaction
B)removing products from a gas or solution reaction
C)decreasing the temperature
D)increasing pressure by adding an inert gas to a reaction in the gas phase
E)All of the above are perturbations to chemical equilibrium.

Question 76

Increasing the temperature of an exothermic reaction results in ________

A)more products and fewer reactants.
B)more reactants and fewer products.
C)more reactants and products.
D)fewer reactants and products.
E)no change in the quantities of reactants and products.

Question 77

Which of the following occurs when reactants are added to a chemical reaction in solution or the gas phase at equilibrium?

A)Q increases and the equilibrium shifts to produce more products.
B)Q increases and the equilibrium shifts to produce more reactants.
C)Q decreases and the equilibrium shifts to produce more products.
D)Q decreases and the equilibrium shifts to produce more reactants.
E)Q is unchanged by the addition of reactants.

Question 78

Addition of products to a chemical reaction in solution or gas phase at equilibrium results in ________

A)an increase in K and a shift in equilibrium to produce more reactants.
B)no change in K and a shift in equilibrium to produce more reactants.
C)a decrease in K and a shift in equilibrium to produce more products.
D)a decrease in K and a shift in equilibrium to produce more reactants.
E)no change in K and a shift in equilibrium to produce more products.

Question 79

How would an increase in temperature affect the following equilibrium? N₂(g)  3H₂(g) 2NH₃(g) H^°  92.0 kJ/mol

A)More product would form and K would increase.
B)More product would form but K would remain constant.
C)K would be unaffected by a temperature change.
D)More reactants would form but K would remain constant.
E)More reactants would form and K would decrease.

Question 80

How would an increase in temperature affect the following equilibrium? H₂O(l ) H₂(g)  O₂(g) H^  482.0 kJ/mol

A)More product would form and K would increase.
B)More product would form but K would remain constant.
C)K would be unaffected by a temperature change.
D)More reactants would form but K would remain constant.
E)More reactants would form and K would decrease.