Q: A solution is prepared by mixing $$0.010\ \mathrm{mol/L}$$ $$\mathrm{Ag^+}$$ and $$0.020\ \mathrm{mol/L}$$ $$\mathrm{Cl^-}. $$The $$K_{sp}$$ for $$\mathrm{AgCl} is$$ $$1.8 \times 10$$^{-10}$$. Calculate Q$$_{sp}$$ and determine if a precipitate will form.

$$Q_{sp} = 2.0 \times 10$$^{-4}$$; Precipitate will form.

Q: The molar solubility of $$\mathrm{$$BaF_2$$} in $$water is $$1.0 \times 10$$^{-3}$$\ \mathrm{mol/L}. $$What is the value of $$K_{sp}$$ for $$\mathrm{$$BaF_2$$}$$?

$$K_{sp} = 4.0 \times 10$$^{-9}$$

Q: Calculate the molar solubility of $$\mathrm{$$MgF_2$$} in$$ $$0.10\ \mathrm{M}$$ $$\mathrm{NaF} if$$ $$K_{sp}$$ for $$\mathrm{$$MgF_2$$} is$$ $$6.4 \times 10$$^{-9}$$.

$$6.4 \times 10$$^{-7}$$\ \mathrm{mol/L}$$

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

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

Question 1

Given the salt $$\mathrm{Pb(IO_3$)_2}$$, which of the following is the correct expression for its solubility product constant ($$K_{sp}$$)?

Accepted Answer

$$K_{sp} = [\mathrm{Pb$$^{2+}$$}][\mathrm{IO_3$^-}]^2$$

Question 2

A solution is prepared by mixing $$0.010\ \mathrm{mol/L}$$ $$\mathrm{Ag^+}$$ and $$0.020\ \mathrm{mol/L}$$ $$\mathrm{Cl^-}. $$The $$K_{sp}$$ for $$\mathrm{AgCl} is$$ $$1.8 	imes 10$$^{-10}$$. Calculate Q$$_{sp}$$ and determine if a precipitate will form.

Accepted Answer

$$Q_{sp} = 2.0 	imes 10$$^{-4}$$; Precipitate will form.

Question 3

The molar solubility of $$\mathrm{$$BaF_2$$} in $$water is $$1.0 	imes 10$$^{-3}$$\ \mathrm{mol/L}. $$What is the value of $$K_{sp}$$ for $$\mathrm{$$BaF_2$$}$$?

Accepted Answer

$$K_{sp} = 4.0 	imes 10$$^{-9}$$

Question 4

Given the formation constant $$K_f$$ for a complex ion is $$1.0 	imes 10^8$, what is the dissociation constant K_D$?

Accepted Answer

$$K_D = 1.0 	imes 10$$^{-8}$$

Question 5

What is the effect on the solubility of $$\mathrm{$$CaF_2$$}$$ when $$\mathrm{NaF} is $$added to the solution?

Accepted Answer

The solubility decreases due to the common ion effect.

Question 6

Calculate the molar solubility of $$\mathrm{$$MgF_2$$} in$$ $$0.10\ \mathrm{M}$$ $$\mathrm{NaF} if$$ $$K_{sp}$$ for $$\mathrm{$$MgF_2$$} is$$ $$6.4 	imes 10$$^{-9}$$.

Accepted Answer

$$6.4 	imes 10$$^{-7}$$\ \mathrm{mol/L}$$

Question 7

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

Accepted Answer

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

Question 8

Which of the following best explains why fluoride ($$\mathrm{F^-}) is $$used in toothpaste to protect tooth enamel?

Accepted Answer

$$\mathrm{F^-}$$ replaces $$\mathrm{OH^-} in $$tooth enamel, forming a less soluble compound.

Question 9

What is the effect of complex ion formation on the solubility of a sparingly soluble salt?

Accepted Answer

It increases the solubility.

Question 10

Which of the following is NOT a state function?

Accepted Answer

Work ($$w)$$

Question 11

What is the sign of enthalpy ($$\Delta H) $$for an exothermic reaction?

Accepted Answer

$$\Delta H is $$negative.

Question 12

Which of the following is a spontaneous process under standard conditions?

Accepted Answer

Iron rusting in moist air

Question 13

Which equation represents the Gibbs Free Energy change?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 14

Which statement best describes the Second Law of Thermodynamics?

Accepted Answer

The entropy of the universe increases in a spontaneous process.

Question 15

Given $$\Delta H^\circ = -100\ \mathrm{kJ}$$ and $$\Delta S^\circ = -200\ \mathrm{J/K} at$$ $$298\ \mathrm{K}$$, calculate $$\Delta G^\circ.$$

Accepted Answer

$$-40.4\ \mathrm{kJ}$$

Question 16

At equilibrium, what is the value of $$\Delta G$$?

Accepted Answer

$$\Delta G = 0$$

Question 17

Given $$\Delta G^\circ = -RT \ln K$$, what is the value of $$K if$$ $$\Delta G^\circ = 0 at$$ $$298\ \mathrm{K}$$?

Accepted Answer

$$K = 1$$

Question 18

For the reaction $$2\mathrm{SO_2$}(g) + \mathrm{O_2$}(g) \rightarrow 2\mathrm{SO_3$}(g)$$, does entropy increase or decrease?

Accepted Answer

Entropy decreases.

Question 19

Which is the best criterion for determining if a process is spontaneous?

Accepted Answer

The sign of $$\Delta G$$

Question 20

What does the sign of the free energy change ($$\Delta G) $$tell us about a chemical reaction?

Accepted Answer

The direction in which the reaction occurs.

Question 21

Which salt will have increased solubility in an acidic solution?

Accepted Answer

$$\mathrm{AgCN}$$

Solubility Equilibria and Thermodynamics: Exam 3 Study Guide

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