Deck 6: Chemical Equilibrium

Question 1

The value of the equilibrium constant K depends on:
i.the initial concentrations of the reactants.II.the initial concentrations of the products.III.the final concentrations of the reactants.IV.the final concentrations of the products.

A) II and III only
B) III and IV only
C) I and II only
D) three of these
E) none of these

Answer 1

none of these

Question 2

Which of the following statements is true?

A) When two opposing processes are proceeding at identical rates, the system is at equilibrium.
B) An endothermic reaction shifts toward reactants when heat is added to the reaction.
C) The concentration of the products equals that of the reactants and is constant at equilibrium.
D) Catalysts are an effective means of changing the position of an equilibrium.
E) None of the above statements is true.

Answer 2

When two opposing processes are proceeding at identical rates, the system is at equilibrium.

Question 3

For the reaction below, Kp = 1.16 at 890.°C.
CaCO₃(s) ⇌ CaO(s) + CO₂(g)
If a 22.0-g sample of CaCO₃ is put into a 10.4-L container and heated to 890.°C, what percent of the CaCO₃ will react to reach equilibrium?

A)12.6%
B)25.3%
C)57.5%
D)100.%
E) 54.9%

Answer 3

57.5%

Question 4

Consider the reaction
CaCl₂(s) + 2H₂O(g) CaCl₂•2H₂O(s)
What is the equilibrium constant for the reaction as written?

A) K = [H₂O]²
B) K =
C) K =
D) K =
E) K =

Question 5

For the reaction below, K_p = 1.16 at 890.°C.CaCO₃(s)
CaO(s) + CO₂(g)
If a 22.0-g sample of CaCO₃ is put into a 10.4-L container and heated to 890.°C, what percent of the CaCO₃ will react to reach equilibrium?
a.
12.6%
b.
25.3%
c.
57.5%
d.

Question 6

Consider the equation 2NOCl₂(g) 2NO(g) + Cl₂(g). The equilibrium constant is0.0142 at 117°C. Calculate K_p.

A) 0.0142
B) 0.136
C) 0.454
D) 4.44 × 10^-4
E) 46.0

Question 7

Choose the mass action or equilibrium expression for the reaction
2SO₂(g) + O₂(g) 2SO₃(g)

A)
B)
C)
D)
E) none of these

Question 8

If, at a given temperature, the equilibrium constant for the reaction H₂(g) + Cl₂(g)
2HCl(g) is 5.0, then the equilibrium constant for the reaction HCl(g)
(1/2)H₂(g) + (1/2)Cl₂(g) can be represented as
a.
0.040.
b.

Question 9

For the reaction 2NCl₃(g) N₂(g) + 3Cl₂(g), the equilibrium pressures are
P(NCl₃) = 0.136 atm
P(N₂) = 2.32 atm
P(Cl₂) = 0.0580 atm
Determine K_p for this reaction.

A) 0.0245
B) 40.9
C) 9.17
D) 1.48
E) 0.989

Question 10

Which of the following statements concerning equilibrium is not true?

A) A system that is disturbed from an equilibrium condition responds in such a way as to restore equilibrium.
B) The value of the equilibrium constant for a given reaction mixture is the same regardless of the direction from which equilibrium is attained.
C) Equilibrium in molecular systems is dynamic, with two opposing processes balancing one another.
D) The equilibrium constant is independent of temperature.
E) A system moves spontaneously toward a state of equilibrium.

Question 11

The value of the equilibrium constant K is dependent on:
I.the temperature of the system.
II.the nature of the reactants and products.
III.the concentration of the reactants.
IV.the concentration of the products.

A) I and II only
B) III and IV only
C) II and III only
D) three of these
E) none of these

Question 12

The value of K_p for the reaction H₂(g) + O₂(g) H₂O₂(g) is 2.3 × 10⁶ at 610K. Determine the value for K for this reaction at 610K.

A) 1.2 × 10¹⁰
B) 4.6 × 10⁴
C) 1.2 × 10⁸
D) 2.3 × 10⁶
E) 4.3 × 10^-7

Question 13

For the reaction 2H₂(g) + O₂(g) 2H₂O(g), what is the relationship between K and K_p at temperature T?

A) K_p = K(RT)²
B) K = K_p(RT)
C) K = K_p
D) K_p = K(RT)
E) K = K_p(RT)²

Question 14

At -90°C, K for the reaction
N₂O₄(g) 2NO₂(g)
Is 4.66 × 10^-8. We introduce 0.038 mol of N₂O₄ into a 2.3-L vessel at -90°C and let equilibrium be established. The total pressure in the system at equilibrium will be

A) 4.66 × 10^-8 atm.
B) 0.25 atm.
C) 0.12 atm.
D) 0.50 atm.
E) 0.23 atm.

Question 15

Indicate the mass action expression for the following reaction:
2X(g) + Y(g)
3W(g) + V(g)

A)
B)
C) [X]²[Y][W]³[V]
D)

Question 16

For the hypothetical reactions 1 and 2, K₁ = 10² and K₂ = 10^-4.
1) A₂(g) + B₂(g) 2AB(g)
2) 2A₂(g) + C₂(g) 2A₂C(g)
3) A₂C(g) + B₂(g) 2AB(g) + (1/2)C₂(g)
What is the value for K for reaction 3?

A) 10^-2
B) 10⁴
C) 10⁶
D) 10²
E) 10^-4

Question 17

The equilibrium constant for A + 2B 3C is 1.0 × 10^-6.Determine the equilibrium constant for 4A +8B 12C

A) 1.0 × 10^-24
B) 1.0 × 10²⁴
C) 1.0 × 10^-6
D) 4 × 10^-24
E) 4× 10^-6

Question 18

The reaction
H₂(g) + I₂(g) 2HI(g)
Has K_p = 45.9 at 763 K. A particular equilibrium mixture at that temperature contains gaseous HI at a partial pressure of 4.46 atm and hydrogen gas at a partial pressure of 0.240 atm. What is the partial pressure of I₂?

A) 1.81 atm
B) 0.240 atm
C) 0.810 atm
D) 36.7 atm
E) 0.405 atm

Question 19

If, at a given temperature, the equilibrium constant for the reaction
H₂(g) + Cl₂(g) ⇌ 2HCl(g) is 5.0, then the equilibrium constant for the reaction
HCl(g) ⇌ (1/2)H₂(g) + (1/2)Cl₂(g) can be represented as

A)0.040.
B) 25.
C) 0.45.
D) 0.20.
E) 5.0.

Question 20

A system at a state of chemical equilibrium is

A) microscopically dynamic and macroscopically dynamic.
B) microscopically dynamic and macroscopically static.
C) microscopically static and macroscopically static.
D) microscopically static and macroscopically dynamic.
E) none of these

Question 21

Consider the following reaction:
2HF(g)
H₂(g) + F₂(g) (K = 1.00 × 10^-2)
Given 1.18 mol of HF(g), 0.880 mol of H₂(g), and 1.03 mol of F₂(g) are mixed in a 3.00-L flask, determine the reaction quotient, Q, and the net direction to achieve equilibrium.

A) Q = 0.651; the equilibrium shifts to the right.
B) Q =0.768; the equilibrium shifts to the left.
C) Q = 0.768; the equilibrium shifts to the right.
D) Q = 0.651; the equilibrium shifts to the left.
E) Q = 1.17; the system is at equilibrium.

Question 22

At a given temperature, the equilibrium constant K for the reaction
2SO₂(g) + O₂(g)
2SO₃(g)
Is 3.0 × 10⁹. If 2.64 mol of SO₂ and 2.98 mol of O₂ are placed in a 1.77-L container and allowed to react to equilibrium at this temperature, what is the concentration of SO₃ at equilibrium?

A) 1.49 M
B) 0.192 M
C) 2.98 M
D) 3.18 M
E) 1.68M

Question 23

At a certain temperature, K for the reaction
2NO₂
N₂O₄
is 7.5 L/mol. If 2.0 mol of NO₂ is placed in a 2.0-liter container and permitted to react at this temperature, calculate the concentration of N₂O₄ at equilibrium.

A) 0.39 mol/L
B) 0.82 mol/L
C) 7.5 mol/L
D) 0.65 mol/L
E) none of these

Question 24

Consider the reaction
2NOBr(g)
2NO(g) + Br₂(g)
A 1)0-L vessel was initially filled with pure NOBr at a pressure of 3.8 atm and 300 K. At equilibrium, the partial pressure of NOBr was 2.2 atm. Determine the value of K_p for the reaction.

A) 1.2
B) 2.4
C) 0.58
D) 0.42
E) 0.73

Question 25

Consider the following reaction:
2NOCl(g)
2NO(g) + Cl₂(g)
Initially pure NOCl(g) is placed in a vessel at 2.96 atm. At equilibrium, 0.410% of the NOCl has decomposed. Determine the value for K_p.

A) 5.00 × 10^-5
B) 2.57 × 10^-8
C) 6.07 × 10^-3
D) 1.03 × 10^-7
E) 2.06 × 10^-7

Question 26

Consider the decomposition of hydrazine as shown below.N₂H₄(g) 2H₂(g) + N₂(g)
At a certain temperature, K_p = 2.5 × 10³. When pure hydrazine is placed in an otherwise empty vessel at this temperature, equilibrium is reached after 30.0% of the hydrazine has decomposed. Calculate the partial pressure of hydrogen gas at equilibrium.

A) 76 atm
B) 5776 atm
C) 54 atm
D) 127 atm
E) none of these

Question 27

A sample of solid NH₄NO₃ was placed in an evacuated container and then heated so that it decomposed explosively according to the following reaction:
NH₄NO₃(s)
N₂O(g) + 2H₂O(g)
At equilibrium, the total pressure in the container was found to be 2.77 atm at a temperature of 500°C. Calculate K_p.

A) 2.77
B) 7.67
C) 85.0
D) 3.15
E) 3.41

Question 28

Consider the equation 2A(g) 2B(g) + C(g). At a particular temperature, K = 1.6 × 10⁴.If you start with 2.0 M of chemical A, calculate the equilibrium concentration of chemical C.

A) 8.3 × 10^-3 M
B) 1.6 × 10^-2 M
C) 6.25 × 10^-5 M
D) 2.0 M
E) 0.98 M

Question 29

Nitric oxide, an important pollutant in air, is formed from the elements nitrogen and oxygen at high temperatures, such as those obtained when gasoline burns in an automobile engine. At 2000°C, K for the reaction N₂(g) + O₂(g) 2NO(g) is 0.01.Predict the direction in which the system will move to reach equilibrium at 2000°C if 0.4 mol of N₂, 0.1 mol of O₂, and 0.08 mol of NO are placed in a 1.0-L container.

A) The system remains unchanged.
B) The concentration of NO will decrease; the concentrations of N₂ and O₂ will remain unchanged.
C) The concentration of NO will decrease; the concentrations of N₂ and O₂ will increase.
D) The concentration of NO will increase; the concentrations of N₂ and O₂ will decrease.
E) More information is necessary.

Question 30

Consider the equation 2A(g) 2B(g) + C(g). At a particular temperature, K = 1.6 × 10⁴.At a higher temperature, K = 1.8 × 10^-5. If you start with 2.0 M of chemical A, calculate the equilibrium concentration of chemical C.

A) 2.6 × 10^-2 M
B) 6.0 × 10^-3 M
C) 1.0 M
D) 2.1 × 10^-2 M
E) none of these

Question 31

Which of the following is an example of a homogeneous equilibrium?

A) CaCl₂(s) + 2H₂O(g) CaCl₂•2H₂O(s)
B) H₂(g) + I₂(s) 2HI(g)
C) NH₄NO₃(s) N₂O(g) + 2H₂O(g)
D) 2N₂O(g) + N₂H₄(g) 3N₂(g) + 2H₂O(g)
E) none of these

Question 32

What is the equilibrium expression for the following reaction?
NH₄NO₃(s)
N₂O(g) + 2H₂O(g)

A)
B)
C)
D) [N₂O][H₂O]²
E) none of these

Question 33

The following reaction is investigated (assume an ideal gas mixture).2N₂O(g) + N₂H₄(g) 3N₂(g) + 2H₂O(g)
Initially there are 0.08 mol of N₂O and 0.38 mol of N₂H₄, in a 30.0-L container. If there is 0.050 mol of N₂O at equilibrium, how many moles of N₂ are present at equilibrium?

A) 0.053
B) 0.045
C) 0.12
D) 0.030
E) 0.15

Question 34

Consider the following reaction (assume an ideal gas mixture).2NOBr(g) 2NO(g) + Br₂(g)
A 3)0-L vessel was initially filled with pure NOBr, at a pressure of 3.9 atm, at 310K.After equilibrium was established, the partial pressure of NOBr was 2.1 atm. What is K_p for the reaction?

A) 0.66
B) 0.22
C) 1.32
D) 1.54
E) 1.1

Question 35

Nitric oxide, an important pollutant in air, is formed from the elements nitrogen and oxygen at high temperatures, such as those obtained when gasoline burns in an automobile engine. At 2000°C, K for the reaction N₂(g) + O₂(g) 2NO(g) is 0.01.A 1-L container originally holds 0.4 mol of N₂, 0.1 mol of O₂, and 0.08 mol of NO. If the volume of the container holding the equilibrium mixture of N₂, O₂, and NO is decreased to 0.5 L without changing the quantities of the gases present, how will their concentrations change?

A) The concentrations of N₂ and O₂ will increase, and the concentration of NO will decrease.
B) The concentrations of N₂, O₂, and NO will decrease.
C) The concentrations of N₂, O₂, and NO will increase.
D) There will be no change in the concentrations of N₂, O₂, and NO.
E) The concentration of NO will increase, and the concentrations of N₂ and O₂ will decrease.

Question 36

For a particular system at a particular temperature, there are ______ equilibrium constant(s) and _______ equilibrium position(s).

A) one, one
B) one, an infinite number of
C) an infinite number of, one
D) an infinite number of, an infinite number of
E) none of these

Question 37

Consider the following equilibrium:
N₂(g) + 3H₂(g)
2NH₃(g)
With K = 2.3 × 10^-6. 1.00 mol each of all reactants and products is placed in a 1.00-L container.Which way will the reaction initially proceed?

A) To the right.
B) We need to know the temperature.
C) The system is at equilibrium.
D) To the left.
E) none of these

Question 38

Consider the following equilibrium: Which of the following is the proper K_eq expression?

A)
B)
C)
D)
E)

Question 39

Consider the equation 2A(g) 2B(g) + C(g). At a particular temperature, K = 1.6 × 10⁴.If you mixed 5.0 mol B, 0.10 mol C, and 0.0010 mol A in a 1-L container, in which direction would the reaction initially proceed?

A) To the right.
B) To the left.
C) The above mixture is the equilibrium mixture.
D) We cannot tell from the information given.

Question 40

Consider the reaction
2SO₂(g) + O₂(g)
2SO₃(g)
At constant temperature. Initially a container is filled with pure SO₃(g) at a pressure of 2 atm, after which equilibrium is allowed to be reached. If y is the partial pressure of O₂ at equilibrium, what is the value of K_p?

A)
B)
C)
D)
E) none of these

Question 41

Nitrogen gas (N₂) reacts with hydrogen gas (H₂) to form ammonia (NH₃). At 200°C in a closed container, 1.2atm of nitrogen gas is mixed with 2.3 atm of hydrogen gas. At equilibrium, the total pressure is 2.1 atm. Calculate the partial pressure of hydrogen gas at equilibrium.

A) 2.3 atm
B) 0.0 atm
C) 1.8 atm
D) 0.20 atm
E) 0.92 atm

Question 42

Explain how a given system at a given temperature has one equilibrium constant but an infinite number of equilibrium positions.

Question 43

Which of the following statements is false?

A) Decreasing the volume of the container shifts the equilibrium to form more PCl₅.
B) Removing PCl₅ from the container shifts the equilibrium to form more PCl₃.
C) Adding PCl₃ to the container shifts the equilibrium to form more PCl₅.
D) Increasing the temperature shifts the equilibrium to form more PCl₃.

Question 44

Raising the pressure by lowering the volume of the container will

A) cause [B] to increase.
B) have no effect.
C) cause [A] to increase.
D) cannot be determined
E) none of the these

Question 45

Consider the following equilibrium: Which of the following statements about the equilibrium is false?

A) Removing HI as it forms forces the equilibrium to the right.
B) Adding more H₂(g) increases the equilibrium constant.
C) This is a heterogeneous equilibrium.
D) If the pressure on the system is increased by changing the volume, the left side is favored.
E) If the system is heated, the right side is favored.

Question 46

Consider the following equilibrium:N₂(g) + 3H₂(g) 2NH₃(g)
with K = 2.3 × 10^-6. 1.00 mol each of all reactants and products is placed in a 1.00-L container.
Calculate the equilibrium concentration of N₂.

A) 1.5 M
B) 2.0 M
C) 0.5 M
D) 2.5 M
E) 1.0 M

Question 47

Consider the equation 2A(g) 2B(g) + C(g). At a particular temperature, K = 1.6 × 10⁴.
Addition of chemical B to an equilibrium mixture of the above will

A) cause [A] to increase.
B) have no effect.
C) cause [C] to increase.
D) cannot be determined
E) none of these

Question 48

Consider the following equilibrium:N₂(g) + 3H₂(g) 2NH₃(g)
with K = 2.3 × 10^-6. 1.00 mol each of all reactants and products is placed in a 1.00-L container.
Calculate the equilibrium concentration of H₂.

A) 0.5 M
B) 1.0 M
C) 2.5 M
D) 2.0 M
E) 1.5 M

Question 49

Consider the following reaction:
How can the equilibrium be shifted to the right?

A) Remove Cl₂.
B) Decrease the pressure by changing the volume.
C) Remove PCl₃.
D) Add more PCl₅.
E) Any of these will shift the equilibrium to the right.

Question 50

Consider the following equilibrium:N₂(g) + 3H₂(g) 2NH₃(g)
with K = 2.3 × 10^-6. 1.00 mol each of all reactants and products is placed in a 1.00-L container.
Calculate the equilibrium concentration of NH₃(g).

A) 3.7 × 10^-3 M
B) 5.4 × 10^-5 M
C) 7.3 × 10^-3 M
D) 4.3 × 10^-6 M
E) none of these

Question 51

To increase the value of K for the exothermic reaction
2H₂(g) + O₂(g)
H₂O(g)
We should

A) decrease the temperature.
B) decrease the total pressure.
C) increase the total pressure.
D) increase the temperature.
E) Two of these are necessary.

Question 52

Consider the equation 2A(g) 2B(g) + C(g). At a particular temperature, K = 1.6 × 10⁴.Placing the equilibrium mixture in an ice bath (thus lowering the temperature) will

A) have no effect.
B) cause [A] to increase.
C) cause [B] to increase.
D) cannot be determined
E) none of these

Question 53

When the substances in the equation below are at equilibrium at pressure P and temperature T, how can the equilibrium be shifted to favor the products?
CuO(s) + H₂(g)
Cu(s) + H₂O(g)
Change in enthalpy = -2.0 kJ.

A) Increase the pressure by adding an inert gas such as nitrogen.
B) Allow some gas to escape at constant pressure and temperature.
C) Decrease the temperature.
D) Increase the pressure by means of a moving piston at constant temperature.
E) Add a catalyst.

Question 54

For a certain reaction at 25.0°C, the value of K is 1.2 × 10^-3. At 50.0°C the value of K is 3.4 × 10^-1. This means that the reaction is

A) endothermic
B) exothermic
C) We need more information.

Question 55

Consider the equation A(aq) + 2B(aq) 3C(aq) + 2D(aq). 40.0 mL of 0.056 M A is mixed with 25.0 mL 0.108 M B. At equilibrium, the concentration of C is 0.0412 M. Calculate K.

A) 0.029
B) 2.6
C) 0.0020
D) 1.9 × 10^-4
E) 0.013

Question 56

Which of the following statements is true?

A) Increasing the temperature of a system at equilibrium always increases the amount of product.
B) Increasing the temperature of a system at equilibrium changes the value of the equilibrium constant.
C) Increasing the temperature of a system at equilibrium always decreases the amount of product.
D) Changing the temperature of a system at equilibrium does not affect the equilibrium position.
E) none of these

Question 57

Ammonia is prepared industrially by the following reaction:
N₂(g) + 3H₂(g)
2NH₃(g)
For the reaction, ΔH° = -92.2 kJ and K (at 25°C) = 4.0 × 10⁸. When the temperature of the reaction is increased to 500°C, which of the following statements is true?

A) Product formation (at equilibrium) is not favored as the temperature is raised.
B) K for the reaction will be larger at 500°C than at 25°C.
C) The reaction of N₂ with H₂ to form ammonia is endothermic.
D) At equilibrium, more NH₃ is present at 500°C than at 25°C.
E) None of these is true.

Question 58

Explain how chemical equilibrium is microscopically dynamic and macroscopically static.

Question 59

Consider the following reaction (assume an ideal gas mixture).2NOBr(g) 2NO(g) + Br₂(g)
A 2)0-L vessel was initially filled with pure NOBr, at a pressure of 3.9 atm, at 310 K.After equilibrium was reached, the volume was increased to 2.0 L, while the temperature was kept at 300 K. This will result in

A) a decrease in K_p.
B) a shift in the equilibrium position to the right.
C) an increase in K_p.
D) a shift in the equilibrium position to the left.
E) none of these

Question 60

Given the reaction A(g) + B(g) C(g) + D(g). You have the gases A, B, C, and D at equilibrium. Upon adding gas A, the value of K

A) depends on whether the reaction is endothermic or exothermic.
B) does not change as long as the temperature is constant.
C) does not change because A does not figure in the ratio of product to reactant.
D) decreases because A is a reactant, so the ratio of product to reactant decreases.
E) increases because when A is added, more products are made, increasing the ratio of product to reactant.

Question 61

To achieve equilibrium, the original reaction mixture will

A) produce more water and oxygen only
B) experience no change in component pressures
C) always move in a direction to lower the total pressure
D) shift toward products
E) shift toward reactants

Question 62

Derive the relationship between K and K_p.

Question 63

Consider the following chemical reaction involving a pure solid sample A that yields products B and C:
3A(s)
3B(g) + 2C(g)
Identify the equilibrium expression of the reaction.​

A) ​
B) ​
C) ​
D) ​
E) ​

Question 64

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.What is the value of the equilibrium constant for the following reaction at 800°C?
C₆H₁₂(chair)
C₆H₁₂(twist-boat)

A) 0.30
B) 2.3
C) 0.23
D) 0.43
E) 0.77

Question 65

Which of the following determines the equilibrium position of a chemical reaction?
1) Initial concentration of the reactants
2) Relative energies of the reactants and products
3) Relative degree of organization of the reactants and products​

A) 1 only
B) ​1, 2, and 3
C) 2 only
D) ​3 only
E) ​1 and 3

Question 66

Write the equilibrium constant expression for the following reaction:
CaCO₃(s)
CaO(s) + CO₂(g)

Question 67

Once equilibrium was established, some additional chlorine gas was added to the system. This resulted in

A) no net change in the amounts of the other reaction components.
B) an increase in the amount of H₂O relative to the equilibrium mixture.
C) a decrease in the amount of H₂O relative to the equilibrium mixture.
D) a decrease in the amount of HCl relative to the equilibrium mixture.
E) both B and D

Question 68

​For a chemical reaction system, Q and K are the reaction quotient and equilibrium constant, respectively. Identify the true statement(s).1. If Q is equal to K, the system is at equilibrium.2. If Q is greater than K, the ratio of initial concentrations of products to initial concentration of reactants is small.3. If Q is less than K, the ratio of initial concentration of products to initial concentration of reactants is large.

A) 1 only
B) 2 only
C) 3 only
D) 1 and 2
E) 2 and 3

Question 69

State Le Châtelier's principle.

Question 70

At 25° C a sample of N₂O₄(g) is placed in an empty cylinder. After equilibrium is reached, the total pressure is 1.5 atm, and 16% (by moles) of the original N₂O₄ has dissociated to NO₂(g). If the volume of the cylinder is increased until the total pressure is 1.0 atm, what percent (by moles) of the original N₂O₄(g) has dissociated at the new equilibrium position? (Hint: First calculate K_p.)

Question 71

In the reaction
P₄(g) 2P₂(g)K_p = 0.500 atm at 1052°C.
In an experiment, P₄(g) is initially placed into a container at 1052°C. The total pressure of the equilibrium mixture of P₄(g) and P₂(g) is 6.00 atm. Calculate the equilibrium pressures of P₄(g) and P₂(g). Calculate the fraction (by moles) of P₄(g) that has dissociated to reach equilibrium.

Question 72

What is the partial pressure of O₂ at equilibrium?

A) 2.18 atm
B) 0.91 atm
C) 1.64 atm
D) 1.18 atm
E) 2.27 atm

Question 73

Identify the true statement(s) about equilibria.1. Homogeneous equilibria is the equilibria of systems in the gas phase.2. Heterogeneous equilibria is the equilibria of systems involving more than one phase.3. The concentration of pure solids and liquids involved in a chemical reaction is not included in the equilibrium expression for a given reaction.​

A) 1 only
B) 2 only
C) 3 only
D) 1, 2, and 3
E) 2 and 3

Question 74

Consider the following reaction, which is involved in the catalytic destruction of ozone by chlorine atoms.
ClO(g) + O₃(g) Cl(g) + 2O₂(g)
K_p = 2.5 × 10⁶ atm at 25° C. In an experiment at 25° C, ClO(g) at 1.0 × 10^-3 atm was mixed with O₃(g) at 2.0 ×10^-5 atm in a rigid vessel. Calculate the equilibrium pressure of O₃(g) and O₂(g).

Question 75

At equilibrium, the partial pressure of HCl will be

A) impossible to determine with this information
B) less than 2 atm
C) zero
D) between 2 and 4 atm
E) more than 4 atm

Question 76

A mixture of O₂(g) and O₃(g) is present at equilibrium in a rigid container at 152 torr and 125° C. The density of the gaseous mixture is 0.228 g/L. Calculate K_p at 125° C for the reaction
3O₂(g)
2O₃(g)

Question 77

​The ratio of the equilibrium pressure (or concentration) for a given substance to a reference pressure (or concentration) for that substance is called the _____ of the substance.

A) ​molarity
B) activity
C) density
D) acclivity
E) ​affinity

Question 78

What is the value of Q₀, the reaction quotient, based on the conditions above?

A) 0.50
B) 0.125
C) 4.00
D) 1.00
E) None of the above