2nd Edition Full Test Bank Chapter.4 Molecules

Student name:__________

TRUE/FALSE - Write 'T' if the statement is true and 'F' if the statement is false.
1) At equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction.

⊚ true
⊚ false

2) 2NO(g) + Cl₂(g)then [NO]² [Cl₂] = K [NOCl]².

⊚ true
⊚ false

3) Cu(s) + H₂O(g) is K = [H₂]/[H₂O].

⊚ true
⊚ false

4) If the system 3H2(g) + N2(g)2NH3(g) is at equilibrium and more N2 is added, a net reaction that consumes some of the added N2 will occur until a new equilibrium is reached.

⊚ true
⊚ false

5) When a reaction system reaches equilibrium, the forward and reverse reactions stop.

⊚ true
⊚ false

MULTIPLE CHOICE - Choose the one alternative that best completes the statement or answers the question.
6) During a chemical reaction, what defines when the concentrations of the reactants and products reach a constant level?

A) elementary process
B) reversible reaction
C) rate law
D) rate constant
E) equilibrium

7) Which substances are included in the equilibrium constant expression, Kc?

A) only pure solids
B) only pure liquids
C) only pure solids and liquids
D) only gases and dissolved substances
E) all participating substances

8) What is defined as a fraction with equilibrium product concentrations in the numerator and equilibrium reactant concentrations in the denominator and each concentration raised to a power equal to the corresponding stoichiometric coefficient in the balanced chemical equation?

A) reversibility expression
B) reaction expression
C) equilibrium expression
D) product quotient
E) mass action

9) If, in a particular process, reactants are able to form products, and products are also able to form reactants, then this process may be described as

A) a reversible process.
B) an elementary process.
C) at equilibrium.
D) forbidden.
E) a forward process.

10) Br₂(g) + 3Cl₂(g)

A) K_c = [Br₂] [Cl₂]/[BrCl₃]
B) K_c = [Br₂] [Cl₂]⁵/[BrCl₃]²
C) K_c = [Br₂] [Cl₂]³/[BrCl₃]²
D) K_c = [BrCl₃]²/([Br₂] × [Cl₂]³)
E) K_c = 2[BrCl₃]²/([Br₂] × 3[Cl₂]³)

11) 12CO₂(g) + 6H₂O(g)

A)
B)
C)
D)
E)

12) Write the equilibrium constant expression for the reaction shown.

A)
B)
C)
D)
E)

13) Write the equilibrium constant expression for the reaction shown.

A)
B)
C)
D)
E)

14) Br₂(g) + 3Cl₂(g)?

A) 0.014
B) 108
C) 18
D) 12
E) 432

15) 2H₂O(g) + O₂(g) In a particular experiment, 1.75 moles of H₂O₂ were placed in a 2.5-L reaction chamber at 307ºC. After equilibrium was reached, 1.20 moles of H₂O₂ remained. What is K for the reaction?

A) 2.0 × 10⁻⁴
B) 2.3 × 10⁻²
C) 2.4 × 10^–3
D) 5.5 × 10⁻³
E) 3.9 × 10⁻⁴

16) H₂(g) + I₂(g) In a particular experiment, the concentrations at equilibrium were measured to be [HI] = 0.85 mol/L, [I₂] = 0.60 mol/L, and [H₂] = 0.27 mol/L. What is K for the above reaction?

A) 5.3
B) 0.22
C) 4.5
D) 0.19
E) 1.6 × 10²

17) 2C(g) At 100°C a mixture of these gases at equilibrium showed that [A] = 0.855 M, [B] = 1.23 M, and [C] = 1.75 M. What is the value of K for this reaction?

A) 0.309
B) 0.601
C) 1.66
D) 2.25
E) 3.24

18) COBr₂(g)

A) 5.23
B) 2.14
C) 1.17
D) 0.467
E) 0.191

19) For the nitrogen fixation reaction, 3H2(g) + N2(g)2NH3(g), K = 6.0 × 10−2 at 500°C. If 0.250 M H2 and 0.050 M NH3 are present at equilibrium, what is the equilibrium concentration of N2?

A) 3.3 M
B) 2.7 M
C) 0.20 M
D) 0.083 M
E) 0.058 M

20) The reaction system POBr3(g)POBr(g) + Br2(g) is at equilibrium. Which of the following statements describes the behavior of the system if POBr is added to the container?

A) POBr will be consumed in order to establish a new equilibrium.
B) The partial pressures of POBr3 and POBr will remain steady while the partial pressure of bromine increases.
C) The partial pressure of bromine will increase while the partial pressure of POBr decreases.
D) The partial pressure of bromine remains steady while the partial pressures of POBr3 and POBr increase.
E) The forward reaction will proceed to establish equilibrium.

21) (CH₃)₂CCH₂(g) + H₂O(g) A reaction vessel contains these compounds at equilibrium. What will happen if the volume of the container is reduced by 50% at constant temperature?

A) The forward reaction will proceed in order to reestablish equilibrium.
B) The reverse reaction will proceed in order to reestablish equilibrium.
C) No change occurs.
D) The equilibrium constant will increase.
E) The equilibrium constant will decrease.

22) 2NH₃(g)

A) There will be no effect.
B) More ammonia will be produced at the expense of hydrogen and nitrogen.
C) Hydrogen and nitrogen will be produced at the expense of ammonia.
D) The equilibrium constant will increase.
E) The equilibrium constant will decrease.

23) For the reaction 2X(g) + Y(g)2Z(g), K = 1.00 ×103 at 500 K. If at equilibrium the concentration of X is 0.20 M and the concentration of Y is 0.50 M, what is the equilibrium concentration of Z?

A) 2.2 M
B) 3.2 M
C) 3.5 M
D) 4.5 M
E) 7.1 M

24) At 35ºC, the equilibrium constant for the reaction 2NOCl(g)2NO(g) + Cl2(g) is K = 1.6 × 10−5.An equilibrium mixture was found to have the following concentrations of Cl2 and NOCl: [Cl2] = 1.2 × 10−2 M; [NOCl] = 2.8 × 10−1 M.Calculate the concentration of NO(g) at equilibrium.

A) 1.0 × 10⁻⁴ M
B) 1.0 × 10⁻² M
C) 2.8 × 10⁻¹ M
D) 2.4 × 10⁻² M
E) 1.6 × 10⁻³ M

25) Determine the balanced chemical equation that corresponds to the given equilibrium expression.

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B)
C)
D)
E)

26) Determine the balanced chemical equation that corresponds to the given equilibrium expression.

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B)
C)
D)
E)

27) Which reaction shown will have the highest concentration of products at equilibrium?

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B)
C)
D)
E)

28) Which reaction shown will have the highest concentration of products at equilibrium?

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B)
C)
D)
E)

29) Which reaction shown will have the highest concentration of reactants at equilibrium?

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B)
C)
D)
E)

30) Which reaction shown will have the highest concentration of reactants at equilibrium?

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B)
C)
D)
E)