Test Bank Chapter 12 Reaction Rates And Chemical Equilibrium - Introduction to Chemistry 5e Answer Key + Test Bank by Rich Bauer. DOCX document preview.
Introduction to Chemistry, 5e (Bauer)
Chapter 12 Reaction Rates and Chemical Equilibrium
1) The rate of a reaction can be increased by all of the following except
A) increasing the temperature.
B) increasing the concentration of the reactants.
C) increasing the surface area of the reactants.
D) adding a catalyst.
E) increasing the volume of the reaction vessel.
2) Which of the following will not increase the rate of a reaction?
A) decreasing the temperature
B) decreasing the concentration of the reactants
C) decreasing the surface area of the reactants
D) removing a catalyst
E) All of these will not increase the rate of a reaction.
3) Factors that influence reaction rates include all of the following except the
A) magnitude of the equilibrium constant.
B) reaction temperature.
C) presence of a catalyst.
D) size of solid reactant particles.
E) concentration of reactants.
4) According to collision theory, the increase in the rate constant with increasing temperature is due mostly to the fact that
A) the activation energy decreases with increasing temperature.
B) the fraction of the collisions having sufficient energy to react increases with increasing temperature.
C) the pressure of the reactants increases with increasing temperature.
D) the heat change for most reactions is negative.
E) the fraction of the collisions that have the proper orientation for reaction increases with increasing temperature.
5) Which of the images shows the molecules in a proper orientation for an effective collision for the following reaction?
2HI(g) → H2(g) + I2(g)
A) I only
B) II only
C) III only
D) I and II
E) II and III
6) Which of the following changes will increase the average kinetic energy of the reactants?
A) increasing the surface area of the reactants
B) increasing the concentration of the reactants
C) adding a catalyst
D) increasing the temperature
E) none of these choices
7) Which of the following changes will increase the fraction of collisions that are effective collisions?
A) increasing the temperature
B) increasing the concentration of the reactants
C) decreasing the concentration of the reactants
D) increasing the surface area of the reactants
E) All of these choices are correct.
8) The kinetics of a reaction is studied at 25ºC and at 50ºC. Which of the following statements is correct?
A) The rate of the reaction at 50ºC will be lower than the rate at 25ºC, since the molecules will be moving too fast to collide effectively.
B) The rate of the reaction at 50ºC will be twice that of the rate at 25ºC, since the temperature has doubled.
C) The rate of the reaction at 50ºC will be greater than the rate at 25ºC, since the activation energy will be lower at the higher temperature.
D) The rate of the reaction at 50ºC will be greater than the rate at 25ºC, since a greater fraction of the molecules will possess sufficient energy to react at the higher temperature.
E) None of these statements is correct.
9) Which of the following statements regarding catalysts is incorrect?
A) A catalyst increases the rate of a reaction by giving the reaction an alternate pathway with a lower activation energy.
B) Catalysts need not be present in large amounts because they are regenerated during the reaction.
C) Enzymes act as catalysts in our bodies.
D) In a chemical reaction, the catalyst is shown on the reactant side of the equation.
E) The shape of an active site on an enzyme is unique, allowing it to react with only one substrate.
10) Which of the following statements regarding catalysts is incorrect?
A) A catalyst increases the rate of a reaction by giving the reaction an alternate pathway with lower activation energy.
B) A catalyst is formed temporarily in an early step of a reaction.
C) Most enzyme catalysts are large protein molecules.
D) In a chemical equation the catalyst is shown above the reaction arrow of the equation.
E) The shape of an active site on an enzyme is unique, allowing it to react with only one substrate.
11) Identify any intermediates in the following three-step reaction:
H2C=CH2 + H3O+ → H3C=CH2+ + H2O
H3C=CH2+ + H2O → CH3CH2OH2+
CH3CH2OH2+ + H2O → CH3CH2OH + H3O+
A) H3O+ is an intermediate.
B) H3C=CH2+ is an intermediate.
C) H3C=CH2+, CH3CH2OH2+, and H2O are intermediates.
D) CH3CH2OH2+ is an intermediate.
E) H2O is an intermediate.
12) A catalyst speeds up a chemical reaction by
A) providing an alternate reaction pathway.
B) increasing the activation energy.
C) shifting the equilibrium.
D) increasing the heat of the reaction.
E) decreasing the heat of the reaction.
13) In a chemical reaction at constant temperature, the addition of a catalyst
A) affects the equilibrium constant.
B) increases the average kinetic energy of the reactants.
C) provides an alternate reaction pathway with a different activation energy.
D) decreases the energy released in the chemical reaction.
E) increases the concentration of the products at equilibrium.
14) Identify an intermediate in the following two-step reaction.
Sn2+ + Fe3+ → Sn3+ + Fe2+ Sn3+ + Fe3+ → Sn4+ + Fe2+
A) Sn2+
B) Fe3+
C) Sn3+
D) Fe2+
E) Sn4+
15) Identify the intermediate(s) in the following two-step reaction.
O3(g) ⇌ O2(g) + O(g) O(g) + O3(g) → 2O2(g)
A) O(g)
B) O3(g)
C) O2(g)
D) O2(g) and O(g)
16) Identify the intermediate in the following two-step reaction.
Cr2+(aq) + Sn4+(aq) ⇌ Cr3+(aq) + Sn3+(aq) Cr2+(aq) + Sn3+(aq) → Cr3+(aq) + Sn2+(aq)
A) Sn3+(aq)
B) Sn4+(aq)
C) Sn2+(aq)
D) Cr2+(aq)
E) Cr3+(aq)
17) Identify the intermediate(s) in the following three-step reaction.
Cl2(g) ⇌ 2Cl(g) CHCl3(g) + Cl(g) → HCl(g) + CCl3(g) CCl3(g) + Cl(g) → CCl4(g)
A) CHCl3(g)
B) HCl(g)
C) Cl2(g)
D) Cl(g)
E) Cl(g) and CCl3(g)
18) Identify any intermediates or catalysts in the following two-step reaction:
S2O82− + I− → 2SO42− + I+ I+ + I− → I2
A) S2O82− is an intermediate.
B) S2O82− is a catalyst.
C) I− is a catalyst.
D) I+ is an intermediate.
E) SO42− is a catalyst.
19) Identify any intermediates or catalysts in the following two-step reaction:
H2O2 + 2Br− + 2H+→ 2H2O + Br2 H2O2 + Br2 → 2H+ + O2 + 2Br−
A) H2O2 is an intermediate.
B) H2O2 is a catalyst, Br− is an intermediate.
C) Br− is a catalyst, Br2 is an intermediate.
D) H+ is a catalyst.
E) Br− and H+ are catalysts, Br2 is an intermediate.
20) Identify any intermediates or catalysts in the following two-step reaction:
Cu2+ + H2 → CuH+ + H+ CuH+ + H+ + H2C=CH2 → Cu2+ + H3C-CH3
A) CuH+ is an intermediate.
B) Cu2+ is a catalyst, H+ is an intermediate.
C) Cu2+ is a catalyst, CuH+ is an intermediate.
D) Cu2+ is a catalyst, CuH+ and H+ are intermediates.
E) CuH+ and H+ are catalysts, Cu2+ is an intermediate.
21) Identify the catalyst in the following three-step process for the decomposition of ozone.
O3(g) ⇌ O2(g) + O(g) NO(g) + O3(g) → NO2(g) + O2(g) O(g) + NO2(g) → O2(g) + NO(g)
A) O(g)
B) O3(g)
C) O2(g)
D) NO(g)
E) NO2(g)
22) Identify the catalyst in the following three-step reaction.
NO(g) + O2(g) → NO3(g) NO3(g) + NO(g) → 2NO2(g) NO2(g) + SO2(g) → NO(g) + SO3(g)
A) SO2(g)
B) NO3(g)
C) O2(g)
D) NO(g)
E) NO2(g)
23) Activated complexes are
A) stable molecules that are formed during an early step of a reaction, and consumed in a later step.
B) materials which act to increase the rate of a reaction without themselves being consumed.
C) substances which form during a reaction that have a definite, well-known structure.
D) short-lived, high-energy chemical species that are produced during a reaction.
E) a molecular species with normal chemical bonds that is produced during a reaction.
24) When a chemical system has reached equilibrium
A) the forward and reverse reactions have stopped.
B) the rate of the forward reaction is greater than the rate of the reverse reaction.
C) the rate of the forward reaction is less than the rate of the reverse reaction.
D) the rate of the forward reaction is equal to the rate of the reverse reaction.
E) the equilibrium constant has reached a minimum.
25) In order to write the equilibrium constant expression for a reaction, you must
A) know the mechanism for the reaction.
B) know the rate of the forward and reverse reactions.
C) know the concentrations of all reactants and products.
D) have the balanced chemical equation for the reaction.
E) know the conditions of pressure, temperature, and concentration for the system.
26) The graph shows the change in concentrations of the reactant and product as a reaction proceeds. At what point is equilibrium first reached?
A) I
B) II
C) III
D) IV
E) V
27) Consider the following reaction carried out in a sealed container: 2SO3(g) ⇌ 2SO2(g) + O2(g) A state of equilibrium can be reached if the container initially contains
A) SO3 only.
B) SO2 and O2 only.
C) SO3 and O2 only.
D) SO3, SO2, and O2.
E) any of these combinations of reactants and products.
28) Consider the following reaction carried out in a sealed container: N2(g) + 3H2(g) ⇌ 2NH3(g) A state of equilibrium can be reached if the container initially contains
A) NH3 only.
B) N2 and H2 only.
C) NH3 and N2 only.
D) NH3, N2, and H2.
E) any of these combinations of reactants and products.
29) Consider the following reaction carried out in a sealed container: N2(g) + 3H2(g) ⇌ 2NH3(g) A state of equilibrium cannot be reached if the container initially contains
A) NH3 only.
B) N2 only.
C) NH3 and N2 only.
D) NH3, N2, and H2.
30) Consider the following reaction carried out in a sealed container: 2SO3(g) ⇌ 2SO2(g) + O2(g) A state of equilibrium cannot be reached if the container initially contains
A) SO3 only.
B) O2 only.
C) SO2 and O2 only.
D) SO3 and O2 only.
E) SO3 , SO2 and O2.
31) Given that evaporation is an endothermic process, which of the following sets of changes would cause the following system at equilibrium to shift to increase the number of I2 molecules in the gas phase? I2(s) ⇌ I2(g)
A) Increasing container volume and increasing temperature
B) Increasing container volume and decreasing temperature
C) Decreasing container volume and increasing temperature
D) Decreasing container volume and decreasing temperature
E) Changing volume or temperature will not affect the number of gas molecules present at equilibrium
32) Given that the following reaction is exothermic, which of the following sets of changes would cause the following system at equilibrium to shift to increase the number of N2O4(g) molecules? 2NO2(g) ⇌ N2O4(g) What observation would indicate that the reaction is at equilibrium in a closed container?
A) Increasing container volume and increasing temperature
B) Increasing container volume and decreasing temperature
C) Decreasing container volume and increasing temperature
D) Decreasing container volume and decreasing temperature
E) Changing volume or temperature will not affect the number of gas molecules present at equilibrium
33) Select the correct equilibrium constant expression for the following reaction: H2(g) + I2(g) ⇌ 2HI(g)
A) 
B) 
C) 
D) 
E) 
34) Select the correct equilibrium constant expression for the reaction: CH4(g) + 2H2S(g) ⇌ CS2(g) + 4H2(g)
A) 
B) 
C) 
D) Keq = [CS2][H2]4 − [CH4][H2S]2
E) Keq = [CS2][H2]4 + [CH4][H2S]2
35) Select the correct equilibrium constant expression for the reaction 4NH3(g) + 3O2(g) ⇌ 2N2(g) + 6H2O(g)
A) Keq = 
B) Keq = 
C) Keq = 
D) Keq = [N2]2[H2O]6 − [NH3]4[O2]3
E) Keq = [N2]2[H2O]6 + [NH3]4[O2]3
36) For the reaction, CoO(s) + H2(g) ⇌ Co(s) + H2O(g), at 550°C, the value of the equilibrium constant, K, is 67. The equilibrium constant expression is
A) 
B) 
C) 
D) 
E) 
37) What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state)?
A) A + B ⇌ C
B) 2A + 2B ⇌ C
C) C ⇌ A + B
D) A + B ⇌ 2C
E) 2C ⇌ A + B
38) What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state)?
A) A2 + B ⇌ C
B) 2A + B ⇌ C
C) C ⇌ A + B
D) C ⇌ A2 + B
E) C ⇌ 2A + B
39) What is the balanced chemical equation that corresponds to the equilibrium constant expression (assuming a homogeneous equilibrium in the gas state)?
A) A + B2 ⇌ C + D
B) A + 2B ⇌ C + D
C) C + D ⇌ A + B
D) C + D ⇌ A + B2
E) C + D ⇌ A + 2B
40) Consider the following reaction at equilibrium at a given temperature: 2NH3(g) + heat ⇌ N2(g) + 3H2(g) Which of the following will cause the value of the equilibrium constant for this process to change?
A) Adding more NH3 to the system, with the volume held constant.
B) Increasing the pressure by reducing the volume of the system.
C) Adding an effective catalyst for the process.
D) Raising the temperature of the system.
E) Adding some neon to the system.
41) For a given reaction, which of the following statements can be made about the value of the equilibrium constant?
A) It always remains the same.
B) It increases when the concentration of one of the products is increased.
C) It increases when the concentration of one of the reactants is increased.
D) It changes when temperature is changed.
E) It can be changed by addition of a catalyst.
42) The value of the equilibrium constant for the following reaction is 0.200 at a given temperature 2HI(g) ⇌ H2(g) + I2(g) Find the value of the equilibrium constant for the reaction: H2(g) + I2(g) ⇌ 2HI(g)
A) 0.200
B) 0.0400
C) 5.00
D) 0.500
E) –0.200
43) The value of the equilibrium constant for the following reaction is 16 at a given temperature: CO(g) + H2O(g) ⇌ CO2(g) + H2(g) Find the value of the equilibrium constant for the reaction: H2(g) + CO2(g) ⇌ CO(g) + H2O(g)
A) 16
B) 4.0
C) 8.0
D) 0.062
E) –16
44) The value of the equilibrium constant for the following reaction is 224 at a given temperature: N2(g) + 3H2(g) ⇌ 2NH3(g) Find the value of the equilibrium constant for the reaction: 2NH3(g) ⇌ N2(g) + 3H2(g)
A) 224
B) 0.00446
C) 448
D) 5.02 x 104
E) –224
45) The value of the equilibrium constant for the following reaction is 16 at a given temperature: 2A ⇌ B What is the value of the equilibrium constant for the reaction B ⇌ 2A?
A) 5.0
B) 25
C) 0.20
D) 0.040
E) –5.0
46) The value of the equilibrium constant for the following reaction is 4.0 at a given temperature: A ⇌ 2B What is the value of the equilibrium constant for the reaction 2B ⇌ A?
A) 4.0
B) 0.25
C) 16
D) 0.062
E) –4.0
47) Which equilibrium constant represents a reaction that is product favored?
A) Keq = 0.025
B) Keq = 5.2
C) Keq = 8.4 x 10–5
D) Keq = 6.3 x 105
E) not enough information
48) Which equilibrium constant represents a reaction that is reactant favored?
A) Keq = 0.025
B) Keq = 5.2
C) Keq = 8.4 x 10–5
D) Keq = 6.3 x 105
E) not enough information
49) Which of the following statements is correct for a reaction in which Keq << 1?
A) The forward reaction is faster than the reverse reaction.
B) The reverse reaction is faster than the forward reaction.
C) There are more products than reactants at equilibrium.
D) There are more reactants than products at equilibrium.
E) None of these statements is correct.
50) Which of the following statements is correct for a reaction in which Keq >> 1?
A) The forward reaction is faster than the reverse reaction.
B) The reverse reaction is faster than the forward reaction.
C) There are more products than reactants at equilibrium.
D) There are more reactants than products at equilibrium.
E) None of these statements is correct.
51) Consider the reaction and the value of its equilibrium constant: S2Cl2(g) + Cl2(g) ⇌ 2SCl2(g) Keq = 4
Examine the figure, and determine if the system is at equilibrium. If it is not, in which direction will it proceed to reach equilibrium?
A) The reaction is at equilibrium.
B) The reaction is not at equilibrium; it will shift to the left.
C) The reaction is not at equilibrium; it will shift to the right.
D) It is not possible to tell if the reaction is at equilibrium.
E) To reach equilibrium, the value of Keq must change.
52) Consider the reaction CO(g) + H2O(g) ⇌CO2(g) + H2(g), represented by the following diagram:
What is the composition of this system when the reaction reaches equilibrium?
A) 3 CO, 3 H2O, 7 CO2, 7 H2
B) 1 CO, 1 H2O, 4 CO2, 4 H2
C) 2 CO, 2 H2O, 8 CO2, 8 H2
D) 8 CO, 8 H2O, 2 CO2, 2 H2
E) 4 CO, 6 H2O, 4 CO2, 6 H2
53) The reaction S2Cl2(g) + Cl2(g) ⇌ 2SCl2(g) has an equilibrium constant of K = 8. The image shows a partially reacted system. What is the composition of this system when the reaction reaches equilibrium?
A) 1 S2Cl2, 3 Cl2, 10 SCl2
B) 2 S2Cl2, 4 Cl2, 8 SCl2
C) 3 S2Cl2, 5 Cl2, 6 SCl2
D) 4 S2Cl2, 6 Cl2, 4 SCl2
E) 5 S2Cl2, 7 Cl2, 2 SCl2
54) The value of the equilibrium constant for the following reaction is 0.200 at a given temperature: 2HI(g) ⇌ H2(g) + I2(g) If [HI] = 0.200 M, [H2] = 0.200 M, and [I2] = 0.200 M, determine if the reaction is at equilibrium. If it is not, in which direction will it proceed to reach equilibrium?
A) The reaction is at equilibrium.
B) The reaction is not at equilibrium, it will shift to the left.
C) The reaction is not at equilibrium, it will shift to the right.
D) It is not possible to tell if the reaction is at equilibrium.
E) To reach equilibrium, the value of Keq must change.
55) The value of the equilibrium constant for the following reaction is 16 at a given temperature: CO(g) + H2O(g) ⇌ CO2(g) + H2(g) If [CO] = 4.0 M, [H2O] = 4.0 M, [CO2] = 4.0 M, and [H2] = 4.0 M, determine if the reaction is at equilibrium. If it is not, in which direction will it proceed to reach equilibrium?
A) The reaction is at equilibrium.
B) The reaction is not at equilibrium, it will shift to the left.
C) The reaction is not at equilibrium, it will shift to the right.
D) It is not possible to tell if the reaction is at equilibrium.
E) To reach equilibrium, the value of Keq must change.
56) The value of the equilibrium constant for the following reaction is 224 at a given temperature: N2(g) + 3H2(g) ⇌ 2NH3(g) If [N2] = 10.0 M, [H2] = 10.0 M, and [NH3] = 10.0 M, determine if the reaction is at equilibrium. If it is not, in which direction will it proceed to reach equilibrium?
A) The reaction is at equilibrium.
B) The reaction is not at equilibrium, it will shift to the left.
C) The reaction is not at equilibrium, it will shift to the right.
D) It is not possible to tell if the reaction is at equilibrium.
E) To reach equilibrium, the value of Keq must change.
57) Consider the following reaction at a specific temperature: 2HI(g) ⇌ H2(g) + I2(g) If [HI] = 0.447 M, [H2] = 0.200 M, and [I2] = 0.200 M at equilibrium, calculate the value of the equilibrium constant under these conditions.
A) 0.200
B) 0.0400
C) 0.0895
D) 0.407
E) 0.0447
58) Consider the following reaction at a specific temperature: CO2(g) + H2(g) CO(g) + H2O(g) If [CO2] = 3.60 M, [H2] = 4.00 M, [CO] = 1.18 M, and [H2O] = 2.40 M at equilibrium, calculate the value of the equilibrium ⇌ instant under these conditions.
A) 0.471
B) 0.197
C) 5.08
D) 2.12
E) 0.444
59) Consider the following reaction at a specific temperature: 2HI(g) ⇌ H2(g) + I2(g) If [HI] = 1.17 M, [H2] = 1.37 M, and [I2] = 0.100 M at equilibrium, calculate the value of the equilibrium constant under these conditions.
A) 1.17
B) 1.26
C) 0.100
D) 10.0
E) 8.54
60) Consider the following reaction at a specific temperature: CO2(g) + H2(g) ⇌ CO(g) + H2O(g) If [CO2] = 1.80 M, [H2] = 2.00 M, [CO] = 0.590 M, and [H2O] = 1.20 M at equilibrium, calculate the value of the equilibrium constant under these conditions.
A) 0.471
B) 0.197
C) 5.08
D) 2.12
E) 0.444
61) Write the equilibrium constant expression for the following reaction: 2HgO(s) ⇌ 2Hg(l) + O2(g)
A) 
B) 
C) Keq = [O2]
D) Keq = [Hg]2[O2]
E) 
62) Write the equilibrium constant expression for the following reaction: PbCl2(s) ⇌ Pb2+(aq) + 2Cl–(aq)
A) 
B) Keq = [Pb2+][ Cl−]2
C) 
D) 
E) 
63) Write the equilibrium constant expression for the following reaction: Pb2+(aq) + 2Cl–(aq) ⇌ PbCl2(s)
A) 
B) Keq = [Pb2+][ Cl−]2
C) 
D) 
E) 
64) Write the equilibrium constant expression for the following reaction: CH3NH2(g) + H2O(l) ⇌ CH3NH3+(aq) + OH–(aq)
A) Keq = [CH3NH3+][OH−]
B) 
C) 
D) 
E) 
65) Write the equilibrium constant expression for the reaction: CH3NH3+(aq) + OH–(aq) ⇌ CH3NH2(g) + H2O(l)
A) Keq = [CH3NH3+][OH−]
B) 
C) 
D) 
E) 
66) Consider the following reaction and the value of its equilibrium constant: FeO(s) + CO(g) ⇌ Fe(s) + CO2(g) Keq = 0.67 If the equilibrium concentration of CO is measured at 0.40 M, what is the equilibrium concentration of CO2?
A) 0.40 M
B) 1.1 M
C) 0.67 M
D) 0.27 M
E) 1.7 M
67) Consider the following reaction and the value of its equilibrium constant: FeO(s) + CO(g) ⇌ Fe(s) + CO2(g) Keq = 0.67 If the equilibrium concentration of CO is measured at 0.50 M, what is the equilibrium concentration of CO2?
A) 0.50 M
B) 1.2 M
C) 0.34 M
D) 0.27 M
E) 1.3 M
68) Consider the following reaction and the value of its equilibrium constant: FeO(s) + CO(g) ⇌ Fe(s) + CO2(g) Keq = 0.67 If the equilibrium concentration of CO is measured at 0.15 M, what is the equilibrium concentration of CO2?
A) 0.10 M
B) 1.2 M
C) 0.15 M
D) 0.52 M
E) 0.22 M
69) Consider the following reaction and the value of its equilibrium constant: H2O(g) + Cl2O(g) ⇌ 2HOCl(g) Keq = 0.090 If the equilibrium concentration of HOCl is measured at 0.15 M, what are the equilibrium concentrations of H2O and Cl2O, assuming that they are equal?
A) 0.15 M
B) 0.090 M
C) 0.50 M
D) 0.25 M
E) 0.60 M
70) Consider the following reaction and the value of its equilibrium constant: H2O(g) + Cl2O(g) ⇌ 2HOCl(g) Keq = 0.090 If the equilibrium concentration of HOCl is measured at 0.20 M, what are the equilibrium concentrations of H2O and Cl2O, assuming that they are equal?
A) 0.67
B) 0.20
C) 0.87
D) 0.44
E) 0.49
71) Which one of the following changes has no effect on the position of the equilibrium?
A) concentration change
B) volume change
C) pressure change
D) temperature change
E) addition of a catalyst
72) The position of equilibrium would not be appreciably affected by changes in the volume of the container for
A) NiO(s) + CO(g) ⇌ Ni(s) + CO2(g).
B) BaCO3(s) ⇌ BaO(s) + CO2(g).
C) 2H2O(g) ⇌ 2H2(g) + O2(g).
D) 2CO(g) + O2(g) ⇌ 2 CO2(g).
E) PCl5(s) ⇌ PCl3(g) + Cl2(g).
73) Consider the following system at equilibrium: CH4(g) + 2H2O(g) ⇌ CO2(g) + 4H2(g) What change will cause the equilibrium to shift to form more CO2?
A) increase [H2]
B) decrease [H2O]
C) decrease [CH4]
D) increase [CH4]
E) decrease [H2]
74) Consider the following system at equilibrium: CH4(g) + 2H2O(g) ⇌ CO2(g) + 4H2(g) What change will cause the equilibrium to shift to form more H2?
A) increase [H2]
B) decrease [H2O]
C) decrease the volume of the reaction vessel
D) decrease [CH4]
E) decrease [CO2]
75) Consider the following system at equilibrium: CH4(g) + 2H2O(g) ⇌ CO2(g) + 4H2(g) What change will cause the equilibrium to shift to form more CH4?
A) decrease [H2]
B) increase [H2O]
C) decrease the volume of the reaction vessel
D) increase [CH4]
E) decrease [CO2]
76) Consider the following system at equilibrium: NO(g) + SO3(g) ⇌ NO2(g) + SO2(g) What change will cause the equilibrium to shift to form more SO2?
A) decrease [NO]
B) increase [NO2]
C) decrease the volume of the reaction vessel
D) decrease [NO2]
E) decrease [SO3]
77) Consider the following reaction: N2(g) + 3H2(g) ⇌ 2NH3(g) + heat Which conditions would favor maximum conversion of the reactants to the products?
A) high temperature and high pressure
B) low pressure; temperature is not important
C) high temperature and low pressure
D) low temperature and high pressure
E) low temperature and low pressure
78) Consider the following system at equilibrium: NO(g) + SO3(g) ⇌ NO2(g) + SO2(g) What change will cause the equilibrium to shift to form more NO?
A) increase [SO3]
B) decrease [SO2]
C) decrease the volume of the reaction vessel
D) decrease [NO2]
E) decrease [SO3]
79) Consider the reaction 3Fe(s) + 4H2O(g) ⇌ 4H2(g) + Fe3O4(s) If the total pressure is increased by reducing the volume,
A) the equilibrium constant increases.
B) no change occurs.
C) more Fe(s) is produced.
D) more H2(g) is produced.
E) more H2O(g) is produced.
80) For the reaction CO(g) + 3H2(g) ⇌ CH4(g) + H2O(g) q = −206 kJ What conditions favor maximum conversion of reactants to products?
A) low pressure and low temperature
B) removal of H2(g) and low temperature
C) high pressure and high temperature
D) high pressure and low temperature
E) low pressure and high temperature
81) Consider the following reaction: N2O4(g) ⇌ 2NO2(g) q = +58.2 kJ What will cause an increase in the concentration of NO2 at equilibrium?
A) The NO2 concentration can never change because the reaction is at equilibrium.
B) an increase in temperature
C) an increase in pressure
D) a decrease in volume
E) adding a catalyst
82) Calcium is somewhat insoluble, so the solid commonly forms an equilibrium with its dissolved ions: CaSO4(s) ⇌ Ca2+(aq) + SO42–(aq) All of the following will affect the position of equilibrium, changing the numbers of dissolved ions in solution, except ________.
A) adding Ca(NO3)2
B) adding Na2SO4
C) adding CaSO4(s)
D) adding water
83) Ethane, C2H6, can be formed by reacting acetylene, C2H2, with hydrogen gas as follows: C2H2(g) + H2(g) ⇌ C2H6(g) Exothermic What change will be observed if the temperature of the reaction mixture at equilibrium were increased?
A) The concentration of C2H6 will increase.
B) The concentration of both C2H2 and H2 will increase.
C) The concentration of both C2H2 and H2 will decrease.
D) The concentration of H2 only will decrease.
E) There will be no change in the equilibrium concentrations.
84) Consider the following reaction initially at equilibrium: NO(g) + Cl2(g) ⇌ NOCl2(g) Endothermic What change will be observed if the temperature of the reaction mixture at equilibrium were decreased?
A) The concentration of NOCl2 will be unchanged.
B) The concentration of NOCl2 will decrease.
C) The concentration of NOCl2 will increase.
D) The concentrations of NO and Cl2 will be unchanged.
E) The concentration of NO and Cl2 will double.
85) The high potential-energy chemical species that is produced when an effective collision occurs is called a catalyst.
86) The amount of energy that reactant molecules must possess in order to react is the activation energy.
87) A reaction that has a high activation energy will have a high rate of reaction.
88) A catalyst increases the rate of a reaction by increasing the kinetic energy of the reactants.
89) A catalyst gives an alternate pathway for a reaction that has a lower activation energy.
90) The enzyme sucrase catalyzes the metabolism of sucrose.
91) Catalysts are not included in an overall chemical reaction because they are regenerated during the reaction.
92) An activated complex is a short-lived, high-energy species that is formed during the process of a chemical reaction.
93) An intermediate in a chemical reaction is a species that the reactant molecules interact with during an early step in a reaction that is regenerated during a later step in the reaction.
94) If the average energy of the products of a chemical reaction is greater than the average energy of the reactants, then the reaction is exothermic.
95) When we say that the position of equilibrium lies to the left, it means that there are fewer reactants than products at equilibrium.
96) When square brackets are placed around the formula for a substance in an equilibrium constant expression, it indicates the percent-by-mass concentration of that substance. For example [NaOH] means the percent-by-mass concentration of NaOH.
97) The only condition which can cause the equilibrium constant for a specific reaction to change is a temperature change.
98) The reaction CaCO3(s) ⇌ CaO(s) + CO2(g) is an example of a heterogeneous equilibrium.
99) If heat is added to the system of an endothermic reaction, the equilibrium will shift to make more reactants.
100) Using collision theory, explain why reaction rates generally increase when temperature increases.
101) Using collision theory, explain why reaction rates generally increase when the concentration of one or more of the reactants increases.
102) Consider the reaction shown in the figure. If the initial conditions are the same in both flasks, with the exception of the concentration of the acetic acid, explain why there is a difference in the size of the balloons after the reaction has progressed for 10 seconds.
©Jim Birk
103) What is the relationship between the following two equilibrium constant expressions?
and 
104) Is the system shown in the figure at equilibrium? If not, in which direction must the reaction proceed?
105) If the initial concentrations of reactants and products are substituted into the equilibrium constant expression, and the value obtained is less than the equilibrium constant, is the system in a state of equilibrium, and if not, in which direction will the reaction shift to reach equilibrium? Explain your answer.
106) The value of the equilibrium constant for the following reaction is 224 at a given temperature: N2(g) + 3H2(g) ⇌ 2NH3(g) If [N2] = 5.00 M, [H2] = 5.00 M, and [NH3] = 5.00 M, is the reaction at equilibrium, and if not, in which direction will it shift?
107) Why are the concentrations of pure liquids and solids not included in the equilibrium constant expression for a given reaction?
108) When yeast bread dough is placed in the freezer, it can be stored for a long period of time without the dough "rising." Use kinetics to explain why this is so.
109) If the equilibrium constant at 25°C is 45, and 6.7 x 103 at 80°C, is the reaction endothermic or exothermic? Explain.
110) Consider the reaction and its equilibrium constant: O3(g) + NO(g) ⇌ O2(g) + NO2(g) Keq = 25
Examine the molecular-level diagram and determine if the reaction is at equilibrium, and if not, in which direction it must proceed in order to reach equilibrium.