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Ch 15 Flashcards

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1
Q

The thermochemical equation for the formation of ammonia from elemental nitrogen and hydrogen is as follows.
N2(g) + 3 H2(g) 2 NH3(g) ΔH = –92.2 kJ

Given a system that is initially at equilibrium, which of the following actions cause the reaction to proceed to the left?
adding N2(g)
removing NH3(g)
adding a catalyst
decreasing the temperature
removing H2(g)

A

e.

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2
Q

In 1913, the Haber-Bosch process was patented. The product of the Haber-Bosch process is ________.

A

ammonia

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3
Q

When gaseous carbon monoxide and hydrogen are combined in a sealed vessel and heated they will eventually form an equilibrium mixture of reactants and products according to the balanced chemical equilibrium below.

CO(g) + 3H2(g)
CH4(g) + H2O(g)

In one such reaction 3 moles of one reactant were combined with 1 mole of the other reactant in a fixed volume vessel and heated to 1200 K. Analysis of the reaction mixture at various times gave the results below. Which component of the reaction mixture is represented by curve B?
hydrogen
carbon monoxide
either methane or water
either hydrogen or carbon monoxide
not enough information to decide

A

b.

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4
Q

Which of the following statements is/are CORRECT?
1. For a chemical system, if the reaction quotient (Q) is greater than K, reactant must be converted to products to reach equilibrium.
2. For a chemical system at equilibrium, the forward and reverse rates of reaction are equal.
3. For a chemical system at equilibrium, the concentrations of products divided by the concentrations of reactants equals one.

A

b.

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5
Q

If the reaction quotient, Q, is greater than K in a gas phase reaction, then
the chemical system has reached equilibrium.
the temperature must be increased for the reaction to proceed in the forward direction.
the reaction will proceed in the forward direction until equilibrium is established.
the reaction will proceed in the backward direction until equilibrium is established.
the reaction will proceed in the direction that increases the number of gas phase particles.

A

d.

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6
Q

A flask contains the following chemical system at equilibrium.
CuCO3(s) Cu2+(aq) + 2 CO32–(aq)
Addition of which of the following substances will increase the solubility of CuCO3(s) in water?
1. aqueous hydrochloric acid
2. aqueous sodium carbonate
3. solid copper(II) carbonate

A

not c.

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7
Q

At 25 °C, 0.138 mg AgBr dissolves in 10.0 L of water. What is the equilibrium constant for the reaction below?
AgBr(s) Ag+(aq) + Br–(aq)
5.40 × 10–13
5.40 × 10–11
1.90 × 10–8
7.35 × 10–7
1.90 × 10–6

A

a.

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8
Q

For the reaction 2NO(g) + O2(g) 2NO2(g) at 750°C, what is the relationship between Kc and Kp?
Kc = Kp
Kc = Kp × (RT)–1
Kc = Kp = 1.0
Kc = Kp × (RT)¾
Kc = Kp × (RT)1

A

e.

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9
Q

Which of the following statements is true if reaction quotient (Q) is greater than equilibrium constant (K)?
Reactant concentrations will increase.
Product concentrations will increase.
Reactants will convert to products.
Standard enthalpy of formation of products decreases.
Standard enthalpy of formation of reactants increases.

A

a.

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10
Q

Consider the following equilibrium at 25 °C:

2 ICl(g) I2(g) + Cl2(g); ΔH = 27 kJ; Kp = 6.2 × 10–6

Which of the following would be true if the temperature were increased to 100 °C?
1. The value of Kp would increase.
2. The concentration of ICl(g) would increase.
3. The partial pressure of I2 would increase.
1 only

A

not b. or d. or a.

maybe c.

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11
Q

In which of the following reactions does a decrease in the volume of the reaction vessel at constant temperature favor the formation of the products?
2 H2(g) + O2(g) 2 H2O(g)
NO2(g) + CO(g) NO(g) + CO2(g)
H2(g) + I2(g) 2 HI(g)
2 O3(g) 3 O2(g)
MgCO3(s) MgO(s) + CO2(g)

A

a.

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12
Q

Which of the following is the correct balanced equation for the equilibrium constant expression given below?

H2(g) + I2(g) HI(g)
HI(g) H2(g) + I2(g)
H2(aq) + I2(aq) HI(aq)
HI(aq) H2(aq) + I2(aq)
2 HI(g) H2(g) + I2(g)

A

a.

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13
Q

For which of the following reactions are the numerical values of Kp and Kc the same?
1. 2SO2(g) + O2(g) 2SO3(g)
2. N2(g) + O2(g) 2NO(g)

  1. H2(g) + I2(g) 2HI(g)
    1 only
    2 only
    1 and 2
    2 and 3
    1, 2, and 3
A

not b.

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14
Q

Consider the following equilibrium.

PCl3(g) + Cl2(g) PCl5(g) ΔH = –92 kJ

The concentration of PCl3 at equilibrium can be increased by:
decreasing the temperature.
adding Cl2 to the system.
adding PCl5 to the system.
increasing the pressure.
adding a catalyst.

A

c.

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15
Q

For which of the following reactions is Kp = Kc?
2 CO2(g) 2 CO(g) + O2(g)
CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g)
C(s) + H2O(g) H2(g) + CO(g)
NH3(g) 3/2 H2(g) + 1/2 N2(g)
2 O3(g) 3 O2(g)

A

b.

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16
Q

Which of the following is the correct balanced equation for the equilibrium constant expression given below?

PbF2(aq) Pb(s) + F2(aq)
PbF2(s) Pb2+(aq) + 2 F–(aq)
Pb2+(aq) + 2 F–(aq) PbF2(s)
Pb(s) + F2(aq) PbF2(aq)
PbF+(aq) + F–(aq) PbF2(aq)

A

b.

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17
Q

What is the Kc equilibrium-constant expression for the following equilibrium?

NiO(s) + H2(g) Ni(s) + H2O(g)

A

a.

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18
Q

Which of the following expressions for K is correct for the reaction given below?

HF(aq) + H2O() F–(aq) + H3O+(aq)

A

c.

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19
Q

Which of the following is always true for a reaction where Kc is at 25°C?
The reaction mixture contains mostly reactants at equilibrium.
The reaction mixture contains mostly products at equilibrium.
The rate of reaction is very slow.
There are approximately equal moles of reactants and products at equilibrium.
Both A and C.

A

a.

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20
Q

The symbol Q is called the ________.

A

the reaction quotient

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21
Q

Write a balanced chemical equation which corresponds to the following equilibrium constant expression.

HNO2(aq) + H2O() NO2–(aq) + H3O+(aq)
NO2–(aq) + H3O+(aq) HNO2(aq) + H2O()
NO2–(aq) + H3O+(aq) HNO2(aq)
H+(aq) + OH–(aq) H2O()
HNO2(aq) NO2–(aq) + H3O+(aq)

A

a.

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22
Q

Which of the following statements is/are correct?
1. Product concentrations appear in the numerator of an equilibrium constant expression.
2. A reaction favors the formation of products if K&raquo_space; 1.
3. Stoichiometric coefficients are used as exponents in equilibrium constant expressions.

A

not c. or d.

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23
Q

The reaction quotient, Q, for a system is . If the equilibrium constant for the system at some temperature is , what will happen as the reaction mixture returns to equilibrium?
The equilibrium constant will increase until it equals the reaction quotient.
There will be a net loss in both product(s) and reactant(s).
There will be a net loss in product(s).
There will be a net loss in reactant(s).
The equilibrium constant will increase.

A

d.

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24
Q

Consider the reaction A(aq) 2 B(aq) where Kc = 4.1 at 25 °C. If 0.50 M A(aq) and 1.5 M B(aq) are initially present in a 1.0 L flask at 25 °C, what change in concentrations (if any) will occur in time?
[A] will decrease and [B] will decrease.
[A] will decrease and [B] will increase.
[A] will increase and [B] will decrease.
[A] will increase and [B] will increase.
[A] and [B] remain unchanged.

A

c.

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25
Q

For the reaction CuCl(s) Cu+(aq) + Cl−(aq), Kc = at 25°C. Which of the following concerning a 125 mL solution containing M Cu+, M Cl− and a large excess of CuCl(s) is/are correct?
1. The mixture is at equilibrium.
2. Additional CuCl(s) must precipitate to attain equilibrium.
3. The reaction quotient (Q) is greater than one.

A

not a.

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26
Q

What is the expression for Kc for the following equilibrium?
CaSO3(s) CaO(s) + SO2(g)

A

b.

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27
Q

Assume that the following endothermic chemical reaction is at equilibrium.
C(s) + H2O(g) H2(g) + CO(g)
Which of the following statements is/are CORRECT?
1. Increasing the concentration of H2(g) will cause the reaction to proceed in the backward direction, increasing the equilibrium concentration of H2O(g).
2. Decreasing the temperature will cause the reaction to proceed in the forward direction, increasing the equilibrium concentration of CO(g).
3. Increasing the amount of C(s) will cause the reaction to proceed in the forward direction, increasing the equilibrium concentration of CO(g).

A

not e. or d. or b.
maybe a.

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28
Q

If a stress is applied to an equilibrium system, the system will respond in such a way as to relieve that stress. This is a statement of ________ principle.

A

Le Chatelier’s

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29
Q

The equilibrium constant, K, is always the same within experimental error for all experiments done at a given temperature. Is this statement true or false?
True
False

A

true

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30
Q

For which of the following reactions are the numerical values of Kp and Kc the same?
1. 2SO2(g) + O2(g) 2SO3(g)
2. N2(g) + O2(g) 2NO(g)
3. H2(g) + I2(g) 2HI(g)

A

d.

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31
Q

Which of the following equilibria would not be affected by pressure change at constant temperature?
CO2(g) + H2(g) CO(g) + H2O(g)
CO(g) + O2(g) CO2(g)
2 Hg() + O2(g) 2 HgO(s)
2 H2(g) + O2(g) 2 H2O()
CaCO3(s) CaO(s) + CO2(g)

A

a.

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32
Q

If the reaction quotient, Q, is equal to K in a gas phase reaction, then
the chemical system has reached equilibrium.
the temperature must be increased for the reaction to proceed in the forward direction.
the reaction will proceed in the forward direction until equilibrium is established.
the reaction will proceed in the backward direction until equilibrium is established.
the reaction will proceed in the direction that increases the number of gas phase particles.

A

a.

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33
Q

Write the expression for Kp for the reaction below.
2 NOBr(g) 2 NO(g) + Br2()

A

b.

34
Q

Which of the following expressions for K is correct for the reaction given below?
Al3+(aq) + 4 OH–(aq) Al(OH)4–(aq)

A

e.

35
Q

Which of the following statements about the reaction quotient, Q, is false?
The value of Q can be used to predict equilibrium concentrations.
It has the same expression as Kc.
Its value is calculated using nonequilibrium concentrations.
If Q > Kc, the reaction must move to equilibrium by forming more reactants.
If Q < Kc, the reaction must move to equilibrium by forming more products.

A

not b.
maybe c., if not -> a

36
Q

A 10.0 g sample of solid NH4Cl is heated in a 5.00 L container to 900 °C. At equilibrium, the pressure of NH3(g) is 1.17 atm. Calculate the equilibrium constant, Kp, for the reactio fon below.
NH4Cl(s) NH3(g) + HCl(g)

1.37
4.93
1.17
2.34
None of these

A

a.

37
Q

Consider the following equilibria.
PbBr2(s) Pb2+(aq) + 2 Br–(aq) K1 = 6.6 × 10–6
Pb(OH)2(s) Pb2+(aq) + 2 OH–(aq) K2 = 1.4 × 10–15
Determine the equilibrium constant, Kc, for the reaction below.
PbBr2(s) + 2 OH–(aq) Pb(OH)2(s) + 2 Br–(aq)

9.2 × 10–21
2.1 × 10–10
6.6 × 10–6
4.7 × 109
1.1 × 1020

A

d.

38
Q

Consider the reaction H2 + I2 2HI for which Kc = 44.0 at a high temperature. If an equimolar mixture of reactants gives the concentration of the product to be 0.50 M at equilibrium, determine the equilibrium concentration of the hydrogen.
7.5 × 10–2 M
1.1 × 10–1 M
3.8 × 10–2 M
1.3 × 101 M
5.7 × 10–3 M

A

not c. or e. or d.

39
Q

At a high temperature, equal concentrations of 0.160 mol/L of H2(g) and I2(g) are initially present in a flask. The H2 and I2 react according to the balanced equation below.
H2(g) + I2(g) 2 HI(g)
When equilibrium is reached, the concentration of H2(g) has decreased to 0.036 mol/L. What is the equilibrium constant, Kc, for the reaction?
3.4
4.0
12
22
48

A

e.

40
Q

Nitrosyl bromide decomposes according to the chemical equation below.
2 NOBr(g) 2 NO(g) + Br2(g)
When 0.260 atm of NOBr is sealed in a flask and allowed to reach equilibrium, 22% of the NOBr decomposes. What is the equilibrium constant, Kp, for the reaction?
2.3 × 10–3
4.5 × 10–3
3.5 × 10–2
4.8 × 10–2
8.0 × 10–2

A

a.

41
Q

Consider the following equilibrium:
CO2(g) + H2(g) CO(g) + H2O(g); Kc = 1.6 at 1260 K

Suppose 0.019 mol CO2 and 0.030 mol H2 are placed in a 3.00-L vessel at 1260 K. What is the equilibrium partial pressure of CO(g)? (R = 0.0821 L · atm/K·mol)

4 atm
0.35 atm
1.6 atm
0.66 atm
1 atm

A

a.

42
Q

The equilibrium constant (Kc) for the decomposition of ammonium hydrogen sulfide, NH4HS(s) NH3(g) + H2S(g), is 1.8 × 10–4 at 25 °C. If excess NH4HS(s) is allowed to equilibrate at 25 °C, what is the equilibrium concentration of NH3?
3.2 × 10–8 M
9.0 × 10–5 M
1.8 × 10–4 M
6.7 × 10–3 M
1.3 × 10–2 M

A

e.

43
Q

At 700 K, Kp for the following equilibrium is 5.6 × 10-3.
2HgO(s) 2Hg(l) + O2(g)

Suppose 43.1 g of mercury(II) oxide is placed in a sealed 4.00-L vessel at 700 K. What is the partial pressure of oxygen gas at equilibrium? (R = 0.0821 L · atm/(K · mol))

0.074 atm
0.0056 atm
2.8 atm
14 atm
1.4 atm

A

b.

44
Q

At 800 K, the equilibrium constant, Kp, for the following reaction is 3.2 × 10–7.
2 H2S(g) 2 H2(g) + S2(g)
A reaction vessel at 800 K initially contains 3.00 atm of H2S. If the reaction is allowed to equilibrate, what is the equilibrium pressure of S2?
8.5 × 10–5 atm
6.2 × 10–3 atm
9.0 × 10–3 atm
1.1 × 10–2 atm
1.4 × 10–2 atm

A

c.

45
Q

Nitrogen and oxygen gases may react to form nitrogen monoxide. At 1500 °C, Kc equals 1.0 × 10−5.
N2(g) + O2(g) 2 NO(g)
If 0.030 mol N2 and 0.030 mol O2 are sealed in a 1.0 L flask at 1500 °C, what is the concentration of NO(g) when equilibrium is established?

3.0 × 10−7 M
4.7 × 10−5 M
9.5 × 10−5 M
3.0 × 10−2 M
9.1 × 101 M

A

c.

46
Q

At 25 °C, the decomposition of dinitrogen tetraoxide
N2O4(g) 2 NO2(g)
has an equilibrium constant (Kp) of 0.144. At equilibrium, the total pressure of the system is 0.0758 atm. What is the partial pressure of each gas?
0.0745 atm NO2(g) and 0.0385 N2O4(g)
0.0549 atm NO2(g) and 0.0209 N2O4(g)
0.0531 atm NO2(g) and 0.0227 N2O4(g)
0.0502 atm NO2(g) and 0.0256 N2O4(g)
0.0381 atm NO2(g) and 0.0377 N2O4(g)

A

not c. or d.

47
Q

What is the reaction quotient, Q, for the equilibrium
CuCl(s) Cu+(aq) + Cl−(aq)

when 0.3746 L of M Cu+ is combined with 0.4326 L of M Cl− in the presence of an excess of CuCl(s)?

A

a.

48
Q

For the reaction given below, 2.00 moles of A and 3.00 moles of B are placed in a 6.00-L container.
A(g) + 2B(g) C(g)

At equilibrium, the concentration of A is 0.230 mol/L. What is the value of Kc?

1.20
1.53
5.22
0.230
0.449

A

not b. or e. or a
pretty sure it is e.
answer bank wrong

49
Q

Given the following chemical equilibrium COCl2(g) CO(g) + Cl2(g), calculate the value of Kc when Kp = 6.5 × 1011 at 298 K. (R = 0.08206 L⋅atm/mol ⋅ K)
1.5 × 10–12
3.8 × 10–11
1.1 × 109
2.7 × 1010
1.6 × 1013

A

d.

50
Q

Excess Ag2SO4(s) is placed in water at 25 °C. At equilibrium, the solution contains 0.029 M Ag+(aq). What is the equilibrium constant for the reaction below?
Ag2SO4(s) 2 Ag+(aq) + SO42–(aq)
1.8 × 10–7
6.1 × 10–6
1.2 × 10–5
2.4 × 10–5
8.4 × 10–4

A

c.

51
Q

Given the following equilibria,
Ni2+(aq) + 2 OH–(aq) Ni(OH)2(s) K1 = 1.8 × 1015
Ni2+(aq) + 4 CN–(aq) Ni(CN)42–(aq) K2 = 2.0 × 1031
determine the equilibrium constant, Kc, for the following reaction.
Ni(OH)2(s) + 4 CN–(aq) Ni(CN)42–(aq) + 2 OH–(aq)

2.8 × 10–47
9.0 × 10–17
1.8 × 1015
1.1 × 1016
3.6 × 1046

A

d.

52
Q

Sulfuryl chloride decomposes to sulfur dioxide and chlorine.
SO2Cl2(g) SO2(g) + Cl2(g)
Kc is 0.045 at 648 K. If an initial concentration of 0.075 M SO2Cl2 is allowed to equilibrate, what is the equilibrium concentration of Cl2?
0.0034 M
0.030 M
0.040 M
0.058 M
0.075 M

A

c.

53
Q

The equilibrium constant at 25 °C for the dissolution of silver iodide is 8.5 × 10–17.
AgI(s) Ag+(aq) + I–(aq)
If an excess quantity of AgI(s) is added to water and allowed to equilibrate, what is the equilibrium concentration of I–?
7.2 × 10–33 M
4.3 × 10–17 M
8.5 × 10–17 M
6.5 × 10–9 M
9.2 × 10–9 M

A

e.

54
Q

Nitrogen trifluoride decomposes at to form nitrogen and fluorine gases according to the following equation:
2NF3(g) N2(g) + 3F2(g)

2.50-L reaction vessel is initially charged with 1.22 mol of NF3 and allowed to come to equilibrium at 800 K. Once equilibrium is established, the reaction vessel is found to contain 0.0194 mol of N2. What is the value of Kp at this temperature? (R = 0.0821 L⋅atm/mol⋅K)

2.68 × 10–6
1.91 × 10–3
1.79 × 10–3
2.77 × 10–6
4.43 × 10–7

A

b.

55
Q

A 3.50-mol sample of HI is placed in a 1.00-L vessel at 460°C, and the reaction system is allowed to come to equilibrium. The HI partially decomposes, forming 0.266 mol H2 and 0.266 mol I2 at equilibrium. What is the equilibrium constant Kc for the following reaction at 460°C?
½ H2(g) + ½ I2(g) HI(g)

1.23 × 102
8.10 × 10–3
2.40 × 10–2
11.1
6.45

A

d.

56
Q

At a given temperature, 0.0664 mol N2O4(g) is placed in a 1.00 L flask. After reaching equilibrium, the concentration of NO2(g) is 6.1 × 10–3 M. What is Kc for the reaction below?
N2O4(g) 2 NO2(g)
3.7 ×10–5
1.4 ×10–4
5.9 × 10–4
9.6 × 10–2
1.8 × 103

A

c

57
Q

A sample of solid NH4NO3 was placed in an evacuated container and then heated so that it decomposed explosively according to the following equation:
NH4NO3(s) N2O(g) + 2H2O(g)

At equilibrium the total pressure in the container was found to be 2.72 atm at a temperature of 500.°C. Calculate Kp.

1.64
0.822
2.98
80.5
0.745

A

c.

58
Q

Consider the formation of ozone by the following reaction.
3 O2(g) 2 O3(g)

Calculate the value of Kp, given that Kc = 2.5 × 10–29 at 298 K. (R = 0.08206 L⋅atm/mol ⋅ K)

1.0 × 10–30
2.1 × 10–30
2.5 × 10–29
3.3 × 10–28
6.1 ×10–28

A

a.

59
Q

An aqueous mixture of phenol and ammonia has initial concentrations of 0.200 M C6H5OH(aq) and 0.120 M NH3(aq). At equilibrium, the C6H5O–(aq) concentration is 0.050 M. Calculate the equilibrium constant, K, for the reaction below.
C6H5OH(aq) + NH3(aq) C6H5O– + NH4+(aq)

0.10
0.24
2.1
4.2
4.8

A

b.

60
Q

A 2.5 L flask is filled with 0.25 mol SO3, 0.20 mol SO2, and 0.40 mol O2, and allowed to reach equilibrium. Assume the temperature of the mixture is chosen so that Kc = 0.12. Predict the effect on the concentration of SO3 as equilibrium is achieved by using Q, the reaction quotient.
2 SO3(g) 2 SO2(g) + O2(g)
[SO3] will decrease because Q > K.
[SO3] will decrease because Q < K.
[SO3] will increase because Q < K.
[SO3] will increase because Q > K.
[SO3] will remain the same because Q = K.

A

b.

61
Q

For the equilibrium N2O4(g) 2NO2(g), at 298 K, Kp = 0.15. For this reaction system, it is found that the partial pressure of N2O4 is 3.7 × 10–2 atm at equilibrium. What is the partial pressure of NO2 at equilibrium?
4.9 atm
24 atm
0.0016 atm
0.0055 atm
0.074 atm

A

e.

62
Q

Given the equilibrium constants for the following reactions:
4Cu(s) + O2(g) 2Cu2O(s), K1
4CuO(s) 2Cu2O(s) + O2(g), K2

what is K for the system

2Cu(s) + O2(g) 2CuO(s)

equivalent to?

A

a.

63
Q

The following reaction occurred when a 1.0-liter reaction vessel was initially charged with 2.0 moles of N2(g) and 4.0 moles of H2(g):
3H2(g) + N2(g) 2NH3(g)

Once equilibrium was established, the concentration of NH3(g) was determined to be 0.57 M at 700.°C. The value for Kc at 700.°foC for the formation of ammonia is:

3.2 × 10–1
6.1 × 10–3
1.1 × 10–1
6.0 × 10–2
none of these

A

b.

64
Q

Given the equilibrium constants for the equilibria,
NH4+(aq) + H2O(l) NH3(aq) + H3O+(aq); Kc =
2CH3COOH(aq) + 2H2O(l) 2CH3COO−(aq) + 2H3O+(aq); Kc =

determine Kc for the following equilibrium.

CH3COOH(aq) + NH3(aq) CH3COO−(aq) + NH4+(aq)

3.08 × 104
3.25 × 10-5
9.96 × 10-15
1.00 × 1014
1.75 × 10-5

A

a.

65
Q

A 3.00-liter flask initially contains 3.00 mol of gas A and 1.50 mol of gas B. Gas A decomposes according to the following reaction:
3A 2B + C

The equilibrium concentration of gas C is 0.134 mol/L. Determine the value of the equilibrium constant, Kc.

0.172
0.132
3.19 × 10–3
0.370
none of these

A

not b.

66
Q

exGiven the following chemical equilibria,
N2(g) + O2(g) 2 NO(g) K1
N2(g) + 3 H2(g) 2 NH3(g) K2
H2(g) + 1/2 O2(g) H2O(g) K3
Determine the method used to calculate the equilibrium constant for the reaction below.

4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g) K c

A

b.

67
Q

A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given temperature.
3H2 + N2 2NH3

An analysis of the mixture at equilibrium revealed 2.1 mol N2, 2.8 mol H2, and 1.8 mol NH3. How many moles of H2 were present at the beginning of the reaction?

2.8
4.2
4.6
5.5
4.0

A

d.

68
Q

At a given temperature, K = 0.024 for the equilibrium:
PCl5(g) PCl3(g) + Cl2(g)

What is K for:

Cl2(g) + PCl3(g) PCl5(g)?

1700
24
0.00058
42
0.024

A

d.

69
Q

When 0.20 mole HF is dissolved in water to a volume of 1.00 L, 5.8% of the HF dissociates to form F–(aq). What is the equilibrium constant for the reaction?
HF(aq) + H2O() F–(aq) + H3O+(aq)
1.3 × 10–4
7.1 × 10–4
1.2 × 10–2
1.7 × 10–2
6.2 × 10–2

A

b.

70
Q

Exactly 1.0 mol N2O4 is placed in an empty 1.0-L container and allowed to reach equilibrium described by the equation N2O4(g) 2NO2(g).
If at equilibrium the N2O4 is 27.0% dissociated, what is the value of the equilibrium constant, Kc, for the reaction under these conditions?
0.40
2.5
0.29
0.74
0.10

A

a.

71
Q

If Kc = 0.124 for A2 + 2B 2AB, what is the value of Kc for the reaction
4AB 2A2 + 4B?

0.124
0.248
65.0
–0.124
4.03

A

pretty sure it is e.

question bank wrong

72
Q

Consider the reaction below.
2 HF(g) H2(g) + F2(g) (Kc = 1.00 × 10–2)

Given that 1.00 mol of HF(g), 0.241 mol of H2(g), and 0.750 mol of F2(g) are mixed in a 5.00 L flask, determine the reaction quotient, Q.

Q = 0.0452
Q = 0.181
Q = 0.0362
Q = 1.99
None of these

A

b.

73
Q

For the equilibrium PCl5(g) PCl3(g) + Cl2(g), Kc = 4.0 at 228°C. If pure PCl5 is placed in a 1.00-L container and allowed to come to equilibrium, and the equilibrium concentration of PCl5(g) is 0.19 M, what is the equilibrium concentration of PCl3?
0.095 M
0.4 M
0.19 M
0.87 M
0.009 M

A

d.

74
Q

For the reaction N2O4(g) 2NO2(g), Kp = 0.148 at a temperature of 298 K. What is Kp for the following reaction?
12NO2(g) 6N2O4(g)

9.52 × 104
0.888
1.05 × 10–5
1.13
6.76

A

a.

75
Q

When 1.0 mole of acetic acid is diluted with water to a volume of 1.0 L at 25 °C, 0.42% of the acetic acid ionizes to form acetate ion and hydronium ion.
CH3CO2H(aq) + H2O() CH3CO2–(aq) + H3O+(aq)
What percentage of the acid ionizes when 0.75 mole of acetic acid is diluted with water to 1.0 L at 25 °C?

A

75% ?

76
Q

For the equilibrium PCl5(g) PCl3(g) + Cl2(g), Kc = 2.0 × 101 at 240°C. If pure PCl5 is placed in a 1.00-L container and allowed to come to equilibrium, and the equilibrium concentration of PCl3(g) is 0.50 M, what is the equilibrium concentration of PCl5(g)?
1 M
0.25 M
0.025 M
0.012 M
6.3 M

A

d.

77
Q

In an experiment, 0.46 mol H2 and 0.46 mol I2 are mixed in a 1.00-L container, and the reaction forms HI. If Kc = 49. for this reaction, what is the equilibrium concentration of HI?
I2(g) + H2(g) 2HI(g)

0.88 M
0.81 M
0.72 M
0.115 M
0.061 M

A

not b
I’m pretty sure it is a.

question bank wrong

78
Q

Assume that the following chemical reaction is at equilibrium.
2 ICl(g) I2(g) + Cl2(g) ΔH° = +26.9 kJ
At 25 °C, Kp = 2.0 × 105. If the temperature is increase to 45 °C, which statement applies?

Kp will decrease and the reaction will proceed in the backward direction.
Kp will decrease and the reaction will proceed in the forward direction.
Kp will remain unchanged and the reaction will proceed in the forward direction.
Kp will increase and the reaction will proceed in the backward direction.
Kp will increase and the reaction will proceed in the forward direction.

A

not d or b.
maybe e.
has to be c or e.

79
Q

Which of the following is the correct balanced equation for the equilibrium expression given below?

2 SO2(g) + O2(g) 2 SO3(g)
2 SO3(g) 2 SO2(g) + O2(g)
2 SO3(aq) 2 SO2(aq) + O2(aq)
2 SO2(aq) + O2(aq) 2 SO3(aq)
SO2(g) + O2(g) SO3(g)

A

a.

80
Q

Which of the following is the correct balanced equation for the equilibrium constant expression given below?

PbF2(aq) Pb(s) + F2(aq)
PbF2(s) Pb2+(aq) + 2 F–(aq)
Pb2+(aq) + 2 F–(aq) PbF2(s)
Pb(s) + F2(aq) PbF2(aq)
PbF+(aq) + F–(aq) PbF2(aq)

A

b.

81
Q

What is the Kc expression for the equilibrium given below?
CuI(s) Cu+(aq) + I−(aq)

A

a.

82
Q

hi

A

Chem II (13 decks)

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