Q: Given $$K_{sp}$$ for $$\mathrm{AgCl} is$$ $$1.8 \times 10$$^{-10}$$, what is the molar solubility S$ of $$\mathrm{AgCl}$$ in pure water?

$$1.3 \times 10$$^{-5}$$\ \mathrm{mol/L}$$

Q: If $$K_{sp}$$ for $$\mathrm{$$PbCl_2$$} is$$ $$1.7 \times 10$$^{-5}$$, what is the molar solubility S$ of $$\mathrm{$$PbCl_2$$}$$ in pure water?

$$1.6 \times 10$$^{-2}$$\ \mathrm{mol/L}$$

Question 1

For the reaction $$\mathrm{N_2O_4(g) \rightleftharpoons 2 NO_2$(g)}$$, the equilibrium constant $$K_c at 298 K is$$ $$0.144. If $$the initial concentrations are $$[\mathrm{N_2O_4}] = 0.50\ \mathrm{M}$$ and $$[\mathrm{NO_2$}] = 0.10\ \mathrm{M}$$, which direction will the reaction proceed to reach equilibrium?

Accepted Answer

The reaction will proceed to the right (toward products).

Question 2

Which of the following statements about the equilibrium constant $$K is $$CORRECT?

Accepted Answer

$$K$$ depends on temperature and how the equation is written.

Question 3

Consider the following two reactions:

$$\mathrm{A(g) \rightleftharpoons 2B(g)}$$ with $$K_1$$

$$\mathrm{2B(g) \rightleftharpoons C(g)}$$ with $$K_2$$

What is the equilibrium constant for $$\mathrm{A(g) \rightleftharpoons C(g)}$$?

Accepted Answer

$$K_1$$ 	imes $$K_2$$

Question 4

A reaction has $$\Delta n_{	ext{gas}} = 2. If$$ $$K_c = 0.50 at 400 K$$, what is $$K_p$$? ($$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$})$$

Accepted Answer

$$K_p = K_c(RT)^2$

Question 5

Which of the following changes will NOT affect the position of equilibrium for the reaction $$\mathrm{$$CaCO_3$$(s) \rightleftharpoons CaO(s) + CO_2$(g)}$$?

Accepted Answer

Adding more $$\mathrm{$$CaCO_3$$(s)}$$

Question 6

Which of the following is a Lewis acid?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 7

Calculate the pH of a $$0.10\ \mathrm{M}$$ solution of acetic acid ($$K_a = 1.8 	imes 10$$^{-5}$$) using the small-x approximation.

Accepted Answer

$$2.87$$

Question 8

Which of the following mixtures will produce a buffer solution?

Accepted Answer

$$\mathrm{NH_3$}$$ and $$\mathrm{NH_4Cl}$$

Question 9

A buffer is prepared by mixing $$0.20\ \mathrm{mol} of $$acetic acid ($$\mathrm{HAc}) $$and $$0.10\ \mathrm{mol} of $$sodium acetate ($$\mathrm{NaAc}) in$$ $$1.0\ \mathrm{L}$$ solution. If $$pK_a = 4.74$$, what is the pH of the buffer?

Accepted Answer

$$4.44$$

Question 10

Which of the following statements about buffer solutions is TRUE?

Accepted Answer

A buffer is most effective when $$[\mathrm{A^-}]/[\mathrm{HA}] = 1$$

Question 11

Given $$K_{sp}$$ for $$\mathrm{AgCl} is$$ $$1.8 	imes 10$$^{-10}$$, what is the molar solubility S$ of $$\mathrm{AgCl}$$ in pure water?

Accepted Answer

$$1.3 	imes 10$$^{-5}$$\ \mathrm{mol/L}$$

Question 12

Which of the following is the correct $$K_{sp}$$ expression for $$\mathrm{$$CaF_2$$(s) \rightleftharpoons Ca$$^{2+}$$(aq) + 2F^-(aq)}$$?

Accepted Answer

$$K_{sp} = [\mathrm{Ca$$^{2+}$$}][\mathrm{F^-}]^2$$

Question 13

If $$K_{sp}$$ for $$\mathrm{$$PbCl_2$$} is$$ $$1.7 	imes 10$$^{-5}$$, what is the molar solubility S$ of $$\mathrm{$$PbCl_2$$}$$ in pure water?

Accepted Answer

$$1.6 	imes 10$$^{-2}$$\ \mathrm{mol/L}$$

Question 14

Which of the following is the correct $$K_f$$ expression for the formation of $$[\mathrm{Ag(NH_3$)_2}]^+$$ from $$\mathrm{Ag^+}$$ and $$\mathrm{NH_3$}$$?

Accepted Answer

$$K_f = \dfrac{[\mathrm{Ag(NH_3$)_2}]^+}{[\mathrm{Ag^+}][\mathrm{NH_3$}]^2}$$

Question 15

Which of the following will increase the solubility of $$\mathrm{AgBr(s)} in $$water?

Accepted Answer

Adding $$\mathrm{NaCN}$$

Question 16

A solution contains $$[\mathrm{Ag^+}] = 0.010\ \mathrm{M}$$ and $$[\mathrm{CN^-}] = 0.10\ \mathrm{M}. $$What is the equilibrium concentration of $$[\mathrm{Ag(CN)_2}]^- if$$ $$K_f = 1.0 	imes 10$$^{21}$$?

Accepted Answer

$$0.010\ \mathrm{M}$$

Question 17

Which of the following best describes the effect of increasing temperature on an exothermic reaction at equilibrium?

Accepted Answer

The equilibrium shifts toward the reactants.

Question 18

Which of the following is the correct relationship between $$pK_a$$ and $$K_a$$?

Accepted Answer

$$pK_a = -\log K_a$$

Question 19

A student mixes $$0.10\ \mathrm{mol} of$$ $$\mathrm{NH_3$}$$ and $$0.10\ \mathrm{mol} of$$ $$\mathrm{NH_4Cl} in$$ $$1.0\ \mathrm{L} of $$water. If $$pK_b$$ for $$\mathrm{NH_3$} is$$ $$4.75$$, what is the pH of the solution? ($$pK_a + pK_b = 14.00)$$

Accepted Answer

$$9.25$$

Exam 2 Review: Chemical Equilibrium, Acids and Bases, Buffers, Solubility, and Complex Ions

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