Deck 14: Chemical Equilibrium

Question 1

The equilibrium constant for the reaction below is 1.7*10¹⁷ at 25 C.
H₂ (g) + Br₂(g) 2 HBr (g) K c (25 C) = 1.7*10¹⁷
What can be stated about the relative equilibrium distribution for this mixture?

A) The mixture contains predominantly H₂ at equilibrium.
B) The mixture contains predominantly Br₂ at equilibrium.
C) The mixture contains predominantly HBr at equilibrium.
D) The mixture contains predominantly H₂ and Br₂ at equilibrium.
E) The mixture contains relatively equal amounts of H₂, Br₂ and HBr at equilibrium.

Answer 1

The mixture contains predominantly HBr at equilibrium.

Question 2

The equilibrium constant, K c , for the reaction below is 1.2*10⁴⁵ at 25 C. CO (g) + 1 / 2 O₂(g) CO₂ (g) What can be stated about the relative equilibrium composition for this mixture?

A) The mixture contains predominantly CO.
B) The mixture contains predominantly O₂.
C) The mixture contains predominantly CO₂.
D) The mixture contains predominantly CO and O₂.
E) The mixture contains relatively equal amounts of CO, O₂ and CO₂.

Answer 2

The mixture contains predominantly CO₂.

Question 3

Consider the following reaction and its corresponding equilibrium constant:
2 ICl (g) I₂ (g) + Cl₂ (g) K c1 = 0.110 What would be the equilibrium constant for the following reaction?
ICl (g) 1 / 2 I₂ (g) + 1 / 2 Cl₂ (g) K c2 = ??

A) 0.0121
B) 0.0550
C) 0.110
D) 0.220
E) 0.332

Answer 3

0.332

Question 4

When the reversible reaction, N₂+ O₂ 2 NO
Has reached a state of dynamic equilibrium , which statement(s) below is(are) true?
I. Both the forward and reverse reactions shut down and no more NO, N₂or O₂are produced.
II. The rate of the forward reaction equals the rate of the reverse reaction.
III. The rate constant of the forward reaction equals the rate constant of the reverse reaction.

A) I only
B) II only
C) III only
D) I and II
E) All of these.

Question 5

Consider the following reaction and its corresponding equilibrium constant.
2 O₃(g) 3 O₂(g) K c = 5.56*10⁵⁵ (at 570 K)
What can be stated about the relative proportions of O₂and O₃ present at equilibrium?

A) Predominately, O₂ exists at equilibrium.
B) Predominately, O₃ exists at equilibrium
C) Comparable amounts of O₂ and O₃ are present at equilibrium.
D) More information is needed to predict relative proportions of O₂ and O₃.

Question 6

Given the following two reactions and their corresponding equilibrium constants:
N₂(g) + O₂(g) 2 NO (g) K c1 = 4.3*10 -²⁵ 2 NO₂ (g) 2 NO (g) + O₂(g) K c2 = 1.6 10 - 10 Combine these two reactions in a manner such that they sum to the net reaction that follows and then evaluate its equilibrium constant. N₂(g) + 2 O₂(g) 2 NO₂ (g) K net = ??

A) 6.9×10 ^{- 35}
B) 7×10 ^{- 15}
C) 6.3×10⁹
D) 3.7×10¹⁴
E) 2.3×10²⁴

Question 7

Given the following two reactions and their corresponding equilibrium constants, K c , at 298 K:
1 / 2 N₂(g) + 1 / 2 O₂ NO (g) K c1 = 6.49*10^{- 16} 2 NO₂ (g) 2 NO (g) + O₂(g) K c2 = 4.25*10^{- 13} What would be the equilibrium constant , K c , for the net reaction given below?
N₂(g) + 2 O₂(g) 2 NO₂ (g) K c, net = ??

A) 1.79×10 ^{- 43}
B) 2.76×10 ^{- 28}
C) 9.91×10 ^{- 19}
D) 1.53×10 ^{- 3}
E) 5.99×10⁴

Question 8

Given the following information, HF (aq) H + (aq) + F - (aq) K c = 6.8*10^{- 4} H₂ C₂ O₄ (aq) 2 H + (aq) + C₂ O₄ 2 - (aq) K c = 3.8*10^{- 6} What is the value of the equilibrium constant for the following reaction?
2 HF (aq) + C₂ O₄ 2 - (aq) 2 F - (aq) + H₂ C₂ O₄ (aq) K c = ??

A) - 5.2×10 ^{- 9}
B) 2.6×10 ^{- 9}
C) 9.9×10 ^{- 8}
D) 1.4×10 ^{- 3}
E) 0.12

Question 9

The equilibrium constant for the reaction below is 2.5*10⁹ at 25 C.
2 HCl (g) H₂ (g) + Cl₂ (g) K eq (25 C) = 3.2*10^{- 34}
What can be stated about the relative equilibrium distribution for this mixture?

A) The mixture contains predominantly H₂.
B) The mixture contains predominantly Cl₂.
C) The mixture contains predominantly HCl.
D) The mixture contains predominantly H₂ and Cl₂.
E) The mixture contains relatively equal amounts of H₂, Cl₂ and HCl.

Question 10

At 400 C the value of K p for the equilibrium 2 NO (g) + O₂(g) 2 NO₂ (g) is 1.0*10⁶ . What is the value of K p for the equilibrium 2 NO₂ (g) 2 NO (g) + O₂(g)?

A) 1.0×10 ^{- 6}
B) (1.0×10⁶)(RT) ^{- 1}
C) (1.0×10⁶)(RT)³
D) 3(1.0×10⁶)/2
E) K _p cannot be determined

Question 11

Given:
2 NO (g) + 2 H₂ (g) N₂(g) + 2 H₂ O (g) K c1 = 6.5*10² What is the equilibrium constant for the following reaction?
1 / 2 N₂(g) + H₂ O (g) NO (g) + H₂ (g) K c2 = ??

A) - 325
B) 2.37×10 ^{- 6}
C) 3.92×10 ^{- 2}
D) 2.55×10¹
E) 4.23×10⁵

Question 12

For the reaction C₂ H₆(g) + 7 / 2 O₂(g) 2 CO₂ (g) + 3 H₂ O (g), the expression for K p is

A)
B)
C)
D)
E)

Question 13

What is the equilibrium constant expression for the following reaction?
2 SO₂ (g) + O₂(g) 2 SO₃(g)

A)
B)
C)
D)
E) K _p = P_SO2²P_O2P_SO3²

Question 14

For the reaction 2 SO₂ (g) + Cl₂ (g) 2 SO₂ Cl₂ (g), the expression for K c is

A)
B)
C)
D)
E)

Question 15

Given:
2 Cl₂ (g) + 2 H₂ O (g) 4 HCl (g) + O₂(g) K c (480 C) = 0.0752 What would be the equilibrium constant, K c , for the equation that follows?
Cl₂ (g) + H₂ O (g) 2 HCl (g) + 1 / 2 O₂(g) K c (480 C) = ??

A) 5.66×10 ^{- 3}
B) 0.0376
C) 0.0752
D) 0.150
E) 0.274

Question 16

At 700 C, K c = 0.112 for the reaction:
SO₂ (g) + 1 / 2 O₂(g) SO₃(g) What is the value of the equilibrium constant for the following reaction at 700 C?
2 SO₂ (g) + O₂(g) 2 SO₃(g) K c = ?

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

Question 17

For the reaction 2 C₂ H₂ (g) + 5 O₂(g) 4 CO₂ (g) + 2 H₂ O (g), the expression for K c is

A)
B)
C)
D)
E)

Question 18

Given:
H₂ O (g) + CO (g) H₂ (g) + CO₂ (g) K c = 1.60 FeO (s) + CO (g) Fe (s) + CO₂ (g) K c = 0.67 What is the equilibrium constant for the following reaction?
Fe (s) + H₂ O (g) FeO (s) + H₂ (g) K c = ??

A) 0.42
B) 0.93
C) 1.07
D) 2.27
E) 2.39

Question 19

Given:
N₂(g) + 3 H₂ (g) 2 NH₃K c (eq 1) = 2.25*10^{- 6} What is the equilibrium-constant, K c , for the formation of one mole of ammonia from nitrogen and hydrogen at 600 K as shown below?
1 / 2 N₂(g) + 3 / 2 H₂ (g) NH₃K c (eq 2) = ??

A) 2.25×10 ^{- 6} (equilibrium-constants are constant at a given temperature)
B) 1.13×10 ^{- 6}
C) 1.5×10 ^{- 3}
D) 5.05×10 ^{- 12}
E) 4.5×10 ^{- 6}

Question 20

The equilibrium constant for the reaction below is 2.5*10⁹ at a particular temperature.
2 SO₂ (g) + O₂(g) 2 SO₃(g)
What can be stated about the relative equilibrium distribution for this mixture?

A) The mixture contains predominantly SO₃.
B) The mixture contains predominantly O₂.
C) The mixture contains predominantly SO₂.
D) The mixture contains predominantly SO₂ and O₂.
E) The mixture contains relatively equal amounts of SO₂, O₂ and SO₃.

Question 21

For the reaction 2 H₂ O (g) 2 H₂ (g) + O₂(g), the relation between K p and K c is:

A) K _p = K _c
B) K _p = K _c(RT)
C) K _p = K _c(RT)³
D) K _p = K _c(RT) ^{- 3}
E) K _p = K _c(RT) ^{- 1}

Question 22

One mole of SO₂ , two moles of O₂, and two moles of SO₃ are placed in a 1.0 liter flask. If K c for the reaction 2 SO₂ (g) + O₂(g) 2 SO₃(g) is 0.50 at this temperature, what occurs in the flask as equilibrium is approached?

A) [SO₃] increases
B) [O₂] increases
C) [SO₂] decreases
D) No reaction occurs since the system is at equilibrium.
E) The equilibrium concentrations of [O₂] and [SO₂] are very small.

Question 23

A scientist places 0.0050 mol of H₂ , 0.0020 mol of I₂ , and 0.050 mol of HI in a 1.0-L container. K c for H₂ (g) + I₂ (g) 2 HI (g) is 12.5 for this particular experiment. Which statement best describes the results of the experiment?

A) Some HI (g) will form.
B) Some H₂ (g) will form.
C) The system is at equilibrium.
D) The temperature must be known.
E) The pressures must be known.

Question 24

What is the partial pressure equilibrium constant, K p , for the following reaction if the concentration equilibrium constant K c = 7.17*10¹⁵ at 200 K?
N₂(g) + 3 H₂ (g) 2 NH₃(g)

A) K _p = 7.21×10 ^{- 35}
B) K _p = 2.66×10¹³
C) K _p = 4.37×10¹⁴
D) K _p = 1.18×10¹⁷
E) K _p = 1.93×10¹⁸

Question 25

The value of K p is 2.72 at 300 C for the reaction 2 NO (g) + Cl₂ (g) 2 NOCl (g). Calculate the value of K c at 300 C.

A) 5.78×10 ^{- 2}
B) 128
C) 67.0
D) 0.110
E) 2.72

Question 26

For the reaction 2 SO₂ (g) + O₂(g) 2 SO₃(g), K c = 0.15 at 300 K. What is the value of K p for this reaction?
(R = 0.0821 L atm/(mol K)

A) 0.15
B) 6.1×10 ^{- 3}
C) 1.6×10²
D) 6.7
E) 3.7

Question 27

At 525 C, the equilibrium partial pressures for the substances in the reaction 2 SO₂ (g) + O₂(g) 2 SO₃(g) were:
P SO = 0.0150 atm, P SO = 0.253 atm, and P O = 0.365 atm. The value of K p for this temperature is:

A) 1.28×10 ^{- 3}
B) 2.16×10 ^{- 2}
C) 46.2
D) 9.63×10 ^{- 3}
E) 779

Question 28

An experiment begins when a researcher places 0.020 mol of N₂, 0.050 mol of H₂ and 0.080 mol NH₃, all in the gas phase, in a 1.0-L container. Calculate Q for:
N₂(g) + 3 H₂ (g) 2 NH₃(g)

A) 1.28×10 ^{- 3}
B) 2.16×10 ^{- 2}
C) 46.2
D) 3.9×10 ^{- 3}
E) 2.6×10³

Question 29

A researcher places 0.10 mol of CO and 0.20 mol of O₂in a 2.0-L container. Calculate Q for:
2 CO₂ (g) 2 CO (g) + O₂(g)

A) 0.
B) 0.00020
C) 0.0020
D) 0.020
E) the result is indeterminably large

Question 30

Consider the following system at equilibrium and its corresponding concentration equilibrium constant:
3 O₂(g) 2 O₃(g) K c = 1.8*10^{- 56} at 570 K What is the value of K p for this reaction at 570 K?

A) K _p = 3.80×10 ^{- 60}
B) K _p = 3.85×10 ^{- 58}
C) K _p = 8.42×10 ^{- 55}
D) K _p = 8.53×10 ^{- 53}
E) K _p = 1.19×10⁵⁴

Question 31

If K c for N₂O₄ (g) 2 NO₂ is 4.5*10^{- 3} at 25 C, what is the value of K c at 25 C for:
2 NO₂ (g) N₂O₄ (g)

A) 2.2×10 ^{- 2}
B) 9.0×10 ^{- 3}
C) 2.2×10²
D) 4.5×10 ^{- 3}
E) 4.5×10³

Question 32

Consider the following reaction at 1200 K:
CH₄ (g) + H₂ O (g) CO (g) + 3 H₂ (g) K c = 0.26 What is the pressure equilibrium constant, K p ?

A) K _p = 0.26; K _p and K _c are always equivalent.
B) K _p = 2.7×10 ^{- 5}
C) K _p = 1.5×10 ^{- 3}
D) K _p = 6.6×10²
E) K _p = 2.5×10³

Question 33

What is the value of K p for 2 CO (g) + O₂(g) 2 CO₂ (g) if K c = 2.24 10 22 ?
The temperature is 1273 K.

A) K _p = (2.24×10²²)(.0821)(1273)
B) K _p = (2.24×10²²)(.0821)⁵(1273)⁵
C) K _p = (2.24×10²²)(.0821) ^{- 1}(1273) ^{- 1}
D) K _p = (.0821)(1273)(2.24×10²²) ^{- 1}
E) none of these

Question 34

Two moles of SO₂ , two moles of O₂, and two moles of SO₃ are placed in a one liter flask. If K c for the reaction 2 SO₂ (g) + O₂(g) 2 SO₃(g) is 0.50 at this temperature, what occurs in the flask as equilibrium is approached?

A) [SO₃] increases
B) [O₂] increases
C) [SO₂] increases
D) All concentrations remain constant since the system is at equilibrium.
E) The equilibrium concentrations of [O₂] and [SO₂] are very small.

Question 35

What is the value of the concentration equilibrium constant, K c (@1000 K), for the following reaction?
CO (g) + Cl₂ (g) COCl₂ (g) K p = 3.9*10^{- 2} (@ 1000 K)

A) K _c = 4.75×10 ^{- 4}
B) K _c = 3.9×10 ^{- 2}
C) K _c = 0.312
D) K _c = 3.20
E) K _c = 324

Question 36

For the reaction I₂ (g) + Cl₂ (g) 2 ICl (g), the relation between K p and K c is:

A) K _p = K _c
B) K _p = K _c(RT)²
C) K _p = K _c(RT) ^{- 2}
D) K _c = K _p(RT)⁴
E) K _p = K _c(RT)⁴

Question 37

Two (2.00) moles of NO, one (1.00) mole of Cl₂ , and two (2.00) moles of NOCl are placed in a 1.00 liter flask. If K c for 2 NO (g) + Cl₂ (g) 2 NOCl (g) is 2.72 at this temperature, what occurs in the flask as equilibrium is approached?

A) The reaction is at equilibrium, so no reaction occurs.
B) The [NO] increases.
C) The [Cl₂] decreases until [Cl₂] = 0.
D) The [NOCl] increases.
E) The [NO] decreases while [Cl₂] increases.

Question 38

At a certain temperature K c = 9.0 for the equilibrium N₂O₄ (g) 2 NO₂ . What is K c at the same temperature for:
NO₂ (g) 1 / 2 N₂O₄ (g)

A) 1.1
B) 3.0
C) 0.33
D) 9.0
E) none of these

Question 39

For the reaction 4 NH₃(g) + 7 O₂(g) 2 N₂O₄ (g) + 6 H₂ O (g), the relation between K p and K c is:

A) K _p = K _c
B) K _p = K _c(RT) ^{- 3}
C) K _c = K _p(RT) ^{- 3}
D) K _p = K _c(RT) ^{- 9}
E) none of these

Question 40

A researcher begins an experiment by adding 0.050 mol of CO₂ and 0.010 mol of H₂ in a 10.0-L container. Under the appropriate conditions, a reaction occurs:
CO₂ (g) + H₂ (g) CO (g) + H₂ O (g) Previous experiments show that K p for this reaction is 0.030 under these conditions. Which statement best describes the results of the experiment?

A) Some CO₂ (g) will form.
B) Some CO (g) will form.
C) Some H₂ (g) will form.
D) The temperature must be known.
E) The pressures must be known.

Question 41

The reaction of chlorine and water vapor was allowed to reach equilibrium at 25 C:
2 Cl₂ (g) + 2 H₂ O (g) 4 HCl (g) + O₂(g)
The volume of the reactor increased so that the pressure in the reaction chamber at equilibrium decreased from 5 atm to 1 atm. Choose the correct statement below.

A) The number of moles of Cl₂ increase.
B) The number of moles of HCl decrease.
C) The number of moles of H₂O increase.
D) The number of moles of O₂ increase.
E) The number of moles of all substances remain unchanged.

Question 42

Consider the reaction:
PCl 3 (g) + Cl₂ (g) PCl₅ (g) K c = 4.2*10^{- 2}
A chemist charged a 1.00 liter reaction vessel with 0.125 moles of PCl₅ , 0.250 moles of Cl₂ and 0.375 moles of PCl 3 . If the equilibrium constant, K c , for this reaction is 4.2 10 - 2 , what is the reaction quotient, Q c , and what can be stated about the direction in which this reaction is occurring?

A) Q _c = 0.75 and the reaction is proceeding from left to right as written.
B) Q _c = 0.75 and the reaction is proceeding from right to left as written.
C) Q _c = 0.75 and the reaction is at equilibrium.
D) Q _c = 1.33 and the reaction is proceeding from left to right as written.
E) Q _c = 1.33 and the reaction is proceeding from right to left as written.

Question 43

Given:
N₂(g) + 3 H₂ (g) 2 NH₃(g) K p (450 C) = 4.51*10^{- 5} At a single moment, if the partial pressure values for these three components were:
PH ₂= 129 atm P N2 = 38 atm P NH3 = 171 atm What can be stated about the reaction quotient , Q , and the direction that the reaction is preceding?

A) Q = 3.49×10 ^{- 2} and the reaction is preceding from left to right as written.
B) Q = 3.49×10 ^{- 2} and the reaction is preceding from right to left as written.
C) Q = 3.58×10 ^{- 4} and the reaction is preceding from left to right as written.
D) Q = 3.58×10 ^{- 4} and the reaction is preceding from right to left as written.
E) Q = 4.51×10 ^{- 5} and the reaction is at equilibrium.

Question 44

Consider the following reaction at 730 K:
H₂ (g) + I₂ (g) 2 HI (g) In one experiment, the following partial pressures were observed at a single moment in time:
PH ₂= 0.250 atm P I2 = 0.370 atm P HI = 2.13 atm After calculating the reaction quotient, Q p , what can be stated about the reaction above, given K p = 49 at 730 K?

A) Q _p K _p and the reaction is proceeding left to right as written.
B) Q _p K _p and the reaction is proceeding right to left as written.
C) Q _p > K _p and the reaction is proceeding left to right as written.
D) Q _p > K _p and the reaction is proceeding right to left as written.
E) Q _p = K _p and the reaction is at equilibrium.

Question 45

The system is in equilibrium with the concentrations as shown at 222 C:
2 NH₃(g) N₂(g) + 3 H₂ (g) Equilibrium pressure 0.4 atm 0.2 atm 0.6 atm By means of a cold trap, ammonia is removed until its equilibrium partial pressure is 0.1 atm. As this change occurs:

A) the position of equilibrium will shift to the right.
B) the value of the equilibrium constant will increase.
C) both answers a and b are correct.
D) the position of equilibrium will not be affected.
E) the partial pressure of hydrogen will decrease.

Question 46

Consider the following chemical reaction at equilibrium:
2 CH₄ (g) + O₂(g) 2 CO (g) + 4 H₂ (g) What is the effect of adding more O₂to this system at equilibrium?

A) The system momentarily proceeds from the left side to the right side until equilibrium is re-established.
B) The system momentarily proceeds from the right side to the left side until equilibrium is re-established.
C) There is no effect. Equilibrium has already been established.
D) The system proceeds from the right side to the left side until all of the O₂ is consumed.

Question 47

For the reaction I₂ (g) + Cl₂ (g) 2 ICl (g) at equilibrium, an increase in the volume of the reaction vessel would:

A) increase the mole amount of ICl
B) increase the mole amount of I₂
C) decrease the mole amount of Cl₂
D) decrease the mole amount of ICl
E) leave the mole amount of ICl, Cl₂, and I₂ unchanged

Question 48

For the reaction
2 NO (g) + 2 CO (g) N₂(g) + 2 CO₂ (g)
At equilibrium, an increase in the volume of the reaction vessel would:

A) decrease the number of moles of both NO and CO.
B) increase the number of moles of both N₂ and CO₂.
C) decrease the number of moles of both NO and CO₂.
D) increase the number of moles of both NO and CO₂.
E) increase the number of moles of both NO and CO.

Question 49

At 1000 K, the value of the K eq for the following reaction equals 0.338.
2 SO₃(g) 2 SO₂ (g) + O₂(g) K c = 0.338
If the partial pressure values for these three components at a single moment were:
P SO₃ = 0.16 atm P SO₂ = 0.41 atm PO₂ = 2.5 atm What can be stated about the reaction quotient , Q , and the direction that the reaction is preceding?

A) Q = 16.4 and the reaction is preceding from left to right as written.
B) Q = 16.4 and the reaction is preceding from right to left as written.
C) Q = 6.4 and the reaction is preceding from left to right as written.
D) Q = 6.4 and the reaction preceding from right to left as written.
E) Q = 6.4 and the reaction is at equilibrium.

Question 50

Under what conditions does changing the pressure have no effect upon the position of equilibrium?
I. When the total pressure is changed by adding an inert gas.
II. When the total number of moles of gas on the reactant side equals the total number of moles of gas on the product side.
III. When all substances present at equilibrium are aqueous phases.

A) I only
B) II only
C) III only
D) I and II
E) all of these

Question 51

The reaction NO (g) + O₃(g) NO₂ (g) + O₂(g) reaches equilibrium at 310 K. Some of the NO₂ gas is then removed from the reaction chamber. Which of the following statements correctly describes the change that would result when equilibrium is restored?

A) The concentration of NO increases.
B) The concentration of O₂ decreases.
C) The concentration of NO remains the same.
D) The concentration of O₃ decreases.
E) The equilibrium constant decreases.

Question 52

At 100 C, the equilibrium constant for the reaction below is 6.71 10 - 9 . COCl₂ (g) CO (g) + Cl₂ (g) At a particular moment, the following partial pressures were observed:
P COCl2 = 6.12 10 - 2 atm P CO = 1.01 10 - 4 atm P Cl2 = 2.03*10^{- 4}atm After calculating the reaction quotient , what can be stated about the direction in which this reaction is proceeding?

A) Not enough information is provided to make an assessment.
B) This reaction is proceeding left to right as written. (reactants to products)
C) This reaction is proceeding right to left as written. (product to reactants)
D) This reaction is at a state of chemical equilibrium.

Question 53

At 700 C, the equilibrium constant ( K c ) for the reaction
N₂(g) + 3 H₂ (g) 2 NH₃(g) is 2.37 10 - 3 .
If 0.683 mol of N₂, 8.80 mol of H₂ and 0.744 mole of NH₃are mixed in a 1.00 L container at 700 C:

A) the value of Q is unknown.
B) the value of Q is greater than K _c.
C) the value of Q is equal to K _c.
D) the reaction is at equilibrium.
E) the value of Q is less than K _c.

Question 54

The reaction of chlorine and water vapor was allowed to reach equilibrium at 125 C:
2 Cl₂ (g) + 2 H₂ O (g) 4 HCl (g) + O₂(g) If the volume of the reaction chamber were suddenly doubled, at equilibrium:

A) the number of moles of O₂ would decrease.
B) the number of moles of Cl₂ would increase.
C) the number of moles of H₂O would decrease.
D) the number of moles of all gases would be unchanged.
E) cannot be determined from information.

Question 55

For the reaction 2 NH₃(g) N₂(g) + 3 H₂ (g), what would you expect if 0.6 atm of inert neon gas is added at constant volume to the equilibrium mixture of gases?

A) Since neon is more dense than hydrogen, it would suppress the reverse reaction; thus, more hydrogen would be formed.
B) The position of equilibrium would shift to the left.
C) Because neon does not react with any of the other chemical species, it cannot change the equilibrium partial pressures of the reactants or products; therefore, the position of equilibrium will remain the same.
D) Because neon is isoelectronic with ammonia, it would compete with ammonia in the forward reaction; therefore, the equilibrium would shift to the right.
E) Neon acts as a catalyst for the reaction thereby lowering the activation energy for the forward reaction.

Question 56

The reaction 2 NO (g) + 2 CO (g) N₂(g) + 2 CO₂ (g) was allowed to reach equilibrium. Additional NO gas was then injected into the reaction chamber and equilibrium was restored. Choose the correct statement below.

A) All concentrations remain the same.
B) A new equilibrium is obtained such that [CO] decreases.
C) A new equilibrium is obtained such that [N₂] decreases.
D) The value of K _c increases.
E) A new equilibrium is obtained such that both [CO] and [N₂] decrease.

Question 57

Which of the following reactions would shift to the right to favor the product side upon increasing the pressure (through a reduction in the volume of the reaction vessel)?
I. H₂ (g) + C₂ N₂(g) 2 HCN (g)
II. CO (g) + Br₂(g) CO Br₂(g)
III. 6 CO₂ (g) + 6 H₂ O ( ) C₆ H₁₂ O₆ (s) + 6 O₂(g)

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

Question 58

Consider the following reaction:
2 HBr (g) H₂ (g) + Br₂(g) In one experiment, the following partial pressures were observed at a single moment in time:
P HBr = 0.25 atm PH ₂= 0.100 atm PBr₂ = 0.019 atm After calculating the reaction quotient, Q p , what can be stated about the reaction above, given K p = 4.18*10 ^{- 9} ?

A) Q _p K _p and the reaction is proceeding left to right as written.
B) Q _p K _p and the reaction is proceeding right to left as written.
C) Q _p > K _p and the reaction is proceeding left to right as written.
D) Q _p > K _p and the reaction is proceeding right to left as written.
E) Q _p = K _p and the reaction is at equilibrium.

Question 59

For the reaction CO₂ (g) + H₂ (g) H₂ O (g) + CO (g) at equilibrium, increasing the volume of the reaction vessel will:

A) increase [H₂O]
B) increase both [H₂O] and [CO]
C) change K _c
D) cause no change in the number of moles of each substance
E) increase both [CO₂] and [H₂]

Question 60

Consider the Haber process for preparing ammonia from nitrogen and hydrogen as shown below and the reaction s corresponding equilibrium constant at 532 C.
N₂(g) + 3 H₂ (g) 2 NH₃(g) K eq (532 C) = 0.19
At a particular moment, the following equilibrium concentrations were observed:
N₂= 0.079 M, H₂ = 0.12 M and NH₃= 0.0051 M. After calculating the reaction quotient , Q , what can be stated about the direction in which this reaction is proceeding?

A) Not enough information is provided to make an assessment.
B) This reaction is proceeding left to right as written. (reactants to products)
C) This reaction is proceeding right to left as written. (product to reactants)
D) This reaction is at a state of chemical equilibrium.

Question 61

At 125 C, K p = 5.2*10^{- 9} and at 500 C, K p = 0.10 for the reaction:
2 Cl₂ (g) + 2 H₂ O (g) 4 HCl (g) + O₂(g) Choose the correct statement.

A) The reaction is endothermic.
B) The reaction is exothermic.
C) K _c is independent of temperature.
D) The [O₂] decreases with increasing temperature.
E) K _p is directly proportional to the temperature.

Question 62

Which of the following reactions is product favored by a higher temperature ?
I. N₂(g) + 2 O₂+ Heat 2 NO₂ (g)
II. 2 N₂(g) + 6 H₂ O (g) 4 NH₃(g) + 3 O₂(g) (endothermic reaction)
III. C₂ H₄ (g) + 3 O₂(g) 2 CO₂ (g) + 2 H₂ O (g) ( D H 0)

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

Question 63

Which system at equilibrium shifts right ?
I. Increasing the pressure by compression for:
H₂ (g) + I₂ (g) 2 HI (g)
II. Increasing the pressure by compression for:
PCl 3 (g) + Cl₂ (g) PCl₅ (g)
III. Increasing the pressure by addition of Argon, an inert gas:
N₂(g) + 3 H₂ (g) 2 NH₃(g)

A) I only
B) II only
C) I and II
D) I and III
E) All of these

Question 64

For the high temperature equilibrium system, 2 H₂ O (g) 2 H₂ (g) + O₂(g), what will be the effect on the equilibrium concentration of O₂(g) upon:
(1) adding H₂ O (g) and (2) decreasing the pressure of the system?

A) (1) and (2) increase the concentration of O₂
B) (1) increases while (2) decreases the concentration of O₂
C) (1) decreases while (2) increases the concentration of O₂
D) (1) and (2) decrease the concentration of O₂
E) none of these

Question 65

Which system at equilibrium shifts right upon heating?
I. PCl 3 (g) + Cl₂ (g) PCl₅ (g) + 111 kJ
II. N₂(g) + 3 H₂ (g) 2 NH₃(g) (exothermic)
III. N₂(g) + O₂(g) 2 NO ( D H 0)

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

Question 66

Consider the following endothermic reaction at equilibrium:
2 N₂(g) + 6 H₂ O 4 NH₃(g) + 3 O₂(g) Which statement is true?

A) Heat shows up as a product in this reaction and supplying heat favors shifting the direction of the reaction to the reactants.
B) Heat shows up as a product in this reaction and supplying heat favors shifting the direction of the reaction to the products.
C) Heat shows up as a reactant in this reaction and supplying heat favors shifting the direction of the reaction to the reactants.
D) Heat shows up as a reactant in this reaction and supplying heat favors shifting the direction of the reaction to the products.

Question 67

The only factor that causes a change in the numerical value of an equilibrium constant is a(n):

A) change in volume.
B) change in pressure.
C) change in concentrations.
D) addition of a catalyst.
E) change in temperature.

Question 68

Which of the following reactions is product favored by a higher temperature ?
I. N₂(g) + 2 O₂ 2 NO₂ (g) (endothermic reaction)
II. 4 NH₃(g) + 3 O₂(g) 2 N₂(g) + 6 H₂ O (g) ( D H 0)
III. 2 CO₂ (g) + 2 H₂ O (g) C₂ H₄ (g) + 3 O₂(g) + heat

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

Question 69

At 500 C, K p = 4.9*10^{- 5} for the exothermic reaction:
N₂(g) + 3 H₂ (g) 2 NH₃(g) The value of K p at 1000 C is:

A) greater than 4.9×10 ^{- 5}
B) less than 4.9×10 ^{- 5}
C) equal tO₄.9×10 ^{- 5}
D) equal to 0.00
E) insufficient information to reach a conclusion

Question 70

What is the effect upon addition of Argon (an inert gas) to the equilibrium reaction shown below?
N₂O₄ (g) 2 NO₂ (g)

A) No effect
B) The reaction shifts to the right.
C) The reaction shifts to the left.
D) More information is needed.

Question 71

Which of the following reaction(s) at equilibrium would shift to the right upon subjecting it to the conditions stated?
I. Increasing the total pressure of the following reaction mixture by introducing an inert gas such as helium:
2 SO₂ (g) + O₂(g) 2 SO₃ .
II. Increasing the pressure of the following reaction mixture through a reduction in volume of the reaction vessel:
H₂ (g) + I₂ (g) 2 HI (g).
III. Decreasing the pressure of the following reaction mixture through an expansion in volume of the reaction vessel:
Co(H₂ O) 6 2+ (aq) + 4 Cl - (aq) CoCl₄² - (aq) + 6 H₂ O ( )

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

Question 72

Inert helium gas was injected into a reaction vessel of fixed volume containing an equilibrium mixture of 2 SO₂ (g) + O₂(g) 2 SO₃(g). The pressure was increased from 1.0 atm to 2.0 atm by the adding helium. Which of the following statements describes the new equilibrium system?

A) [SO₃] increases
B) [SO₂] increases
C) [SO₃] decreases
D) [O₂] increases
E) [SO₃], [SO₂], and [O₂] remain unchanged

Question 73

Which of the following reactions is product favored by a higher temperature ?
I. Co(H₂ O) 6 2+ (aq) + 4 Cl - (aq) + heat CoCl₄² - (aq) + 6 H₂ O ( )
II. 2 SO₂ (g) + O₂(g) 2 SO₃(D H 0)
III. 6 CO₂ (g) + 6 H₂ O (g) C₆ H₁₂ O₆ (s) + 6 O₂(g) (endothermic reaction)

A) I only
B) II only
C) III only
D) I and III
E) All of these

Question 74

The equilibrium governed by the reaction 4 NH₃(g) + 5 O₂(g) 4 NO (g) + 6 H₂ O (g) undergoes a change in volume from 1.0 L to 2.0 L at 600 C. Choose the correct statement below.

A) The number of moles of H₂O decreases.
B) The number of moles of NO remains the same.
C) The number of moles of NH₃ decreases.
D) The value of K _c increases.
E) The number of moles of both H₂O and O₂ decrease.

Question 75

Which of the following reactions is product favored by increasing the temperature of the reaction mixture?
I. 2 NO₂ (g) N₂(g) + 2 O₂(g) (exothermic)
II. 2 CO₂ (g) + 2 H₂ O (g) + heat C₂ H₄ (g) + 3 O₂(g)
III. 2 KCl (s) + 3 O₂(g) 2 KClO₃(s) ( D H 0)

A) I only
B) II only
C) I and III
D) II and III
E) All of these

Question 76

At constant volume, helium gas was injected into an equilibrium mixture of 2 SO₃(g) 2 SO₂ (g) + O₂(g) The total pressure increased from 1.0 atm to 10.0 atm. Which of the following statements is correct?

A) The concentrations of the reacting gases are unchanged.
B) [SO₃] increases
C) [SO₂] increases
D) [O₂] increases
E) [SO₂] and [O₂] decrease

Question 77

For the reaction H₂ (g) + I₂ (g) 2 HI (g) with D H 0, which of the following stresses when applied to an equilibrium mixture will not increase the amount of HI when equilibrium is reestablished?

A) Add 3 moles of H₂ (g) at constant volume.
B) Lower the temperature at constant volume.
C) Increase the volume of the mixture.
D) Add 1 mole of I₂ (g) at constant pressure.
E) All of these increase the amount of HI.

Question 78

At equilibrium, the endothermic reaction N₂(g) + O₂(g) 2 NO (g) produces a maximum amount of NO for which of the following conditions?

A) high P
B) high T
C) low P
D) low T
E) a combination of low P and low T

Question 79

At 600 C, K p = 0.57 for the endothermic reaction:
CO₂ (g) + H₂ (g) CO (g) + H₂ O (g) The value of K p at 300 C is:

A) greater than 0.57
B) equal to 0.57
C) less than 0.57
D) equal to 0.00
E) insufficient information to reach a conclusion

Question 80

Which reaction shown below is shifted in the direction of the products (to the right) by increasing the pressure of the reaction mixture?

A) H₂ (g) + C₂ N₂(g) 2 HCN (g)
B) CO (g) + Br₂(g) CO Br₂(g)
C) CH₄ (g) + 2 H₂ S (g) C S₂(g) + 4 H₂ (g)
D) 2 Na₂ O (s) 4 Na ( ) + O₂(g)
E) None of these.