Equilibrium and Ksp

2 SO3(g) 2 SO2(g) + O2(g)

1. After the equilibrium represented above is established, some pure O2(g) is injected into the reaction vessel at constant temperature. After equilibrium is reestablished, which of the following has a lower value compared to its value at the original equilibrium?

(A)Keq for the reaction

(B)The total pressure in the reaction vessel

(C)The amount of SO3(g) in the reaction vessel

(D)The amount of O2(g) in the reaction vessel

(E) The amount of SO2(g) in the reaction vessel

2 NO(g) + O2(g) 2 NO2(g)H < 0

2. Which of the following changes alone would cause a decrease in the value of Keq for the reaction represented above?

(A)Decreasing the temperature

(B)Increasing the temperature

(C)Decreasing the volume of the reaction vessel

(D)Increasing the volume of the reaction vessel

(E)Adding a catalyst

HC2H3O2(aq) + CN–(aq) HCN(aq) + C2H3O2–(aq)

3. The reaction represented above has an equilibrium constant equal to 3.7x104. Which of the following can be concluded from this information?

(A)CN–(aq) is a stronger base than C2H3O2–(aq).

(B)HCN(aq) is a stronger acid than HC2H3O2(aq) .

(C)The conjugate base of CN–(aq) is C2H3O2–(aq).

(D)The equilibrium constant will increase with an increase in temperature.

(E)The pH of a solution containing equimolar amounts of CN–(aq) and HC2H3O2(aq) is 7.0.

4. What is the molar solubility in water of Ag2CrO4? (The Ksp for Ag2CrO4 is 8x10–12)

(A) 8x10–12M(B) 2x10–12M

(E) M

5. H2C2O4 + 2 H2O 2 H3O+ + C2O42–

Oxalic acid, H2C2O4, is a diprotic acid with K1 = 5.36x10–2 and K2 = 5.3x10–5. For the reaction above, what is the equilibrium constant?

(A) 5.36x10–2(B) 5.3x10–5

(E) 1.9x10–13

6.Samples of F2 gas and Xe gas are mixed in a container of fixed volume. The initial partial pressure of the F2 gas is 8.0 atmospheres and that of the Xe gas is 1.7 atmospheres. When all of the Xe gas reacted, forming a solid compound, the pressure of the unreacted F2 gas was 4.6 atmospheres. The temperature remained constant. What is the formula of the compound?

(A)XeF(B)XeF3(C)XeF4

(D)XeF6(E)XeF8

7. PCl3(g) + Cl2(g) PCl5(g) + energy

Some PCl3 and Cl2 are mixed in a container at 200C and the system reaches equilibrium according to the equation above. Which of the following causes an increase in the number of moles of PCl5 present at equilibrium?

I. Decreasing the volume of the container

II Raising the temperature

III Adding a mole of He gas at constant volume

(A) I only(B) II only

(E) I, II, and III

8. 4 HCl(g) + O2(g) 2 Cl2(g) + 2 H2O(g)

Equal numbers of moles of HCl and O2 in a closed system are allowed to reach equilibrium as represented by the equation above Which of the following must be true at equilibrium?

I. [HCl] must he less than [Cl2].

II. [O2] must be greater than [HCl].

III. [Cl2] must equal [H2O].

(A) I only(B) II only

(E) I, II, and III

9. Barium sulfate is LEAST soluble in a 0.01–molar solution of which of the following?

(A) Al2(SO4)3(B) (NH4)2SO4

(E) BaCl2

10.2 SO2(g) + O2(g) 2 SO3(g)

When 0.40 mole of SO2 and 0.60 mole of O2 are placed in an evacuated 1.00–liter flask, the reaction represented above occurs. After the reactants and the product reach equilibrium and the initial temperature is restored, the flask is found to contain 0.30 mole of SO3. Based on these results, the equilibrium constant, Kc, for the reaction is

(A)20.(B)10.(C)6.7

(D)2.0(E)1.2

11.In which of the following systems would the number of moles of the substances present at equilibrium NOT be shifted by a change in the volume of the system at constant temperature?

a. CO(g) + NO(g) CO2(g) + 1/2 N2(g)

b. N2(g) + 3 H2(g) 2 NH3(g)

c. N2(g) + 2 O2(g) 2 NO2(g)

d. N2O4(g) 2 NO2(g)

e. NO(g) + O3(g) NO2(g) + O2(g)

12.Which of the following is the correct equilibrium expression for the hydrolysis of CO32– ?

a. d.

b. e.

13.H2PO4– + HBO32– HPO42– + H2BO3–

The equilibrium constant for the reaction represented by the equation above is greater than 1.0. Which of the following gives the correct relative strengths of the acids and bases in the reaction?

AcidsBases

a. H2PO4– > H2BO3–HBO32– > HPO42–

b. H2BO3– > H2PO4–HBO32– > HPO42–

c. H2PO4– > H2BO3–HPO42– > HBO32–

d. H2BO3– > H2PO4–HPO42– > HBO32–

e. H2PO4– = H2BO3–HPO42– = HBO32–

14.The solubility of CuI is 2x10–6 molar. What is the solubility product constant, Ksp, for CuI?

a. 1.4x10–3 c. 4x10–12 e. 8x10–18

b. 2x10–6 d. 2x10–12

15.MnS(s) + 2 H+ Mn2+ + H2S(g)

At 25C the solubility product constant, Ksp, for MnS in 5x10–15 and the aciddissociationconstants K1 and K2 for H2S are 1x10–7 and 1x10–13, respectively. What is the equilibrium constant for the reaction represented by the equation above at 25C?

a. d.

b. e.