Q: Calculate the molar solubility of $$\mathrm{$$PbCl_2$$} in $$pure water if $$K_{sp} = 1.17 \times 10$$^{-5}$$.

$$1.48 \times 10$$^{-2}$$\ \mathrm{M}$$

Question 1

Which of the following statements best explains why NaCl is not infinitely soluble in water, despite being considered 'soluble' by solubility rules?

Accepted Answer

At equilibrium, the rate of NaCl dissolving equals the rate of Na+ and Cl- ions recombining to form solid NaCl.

Question 2

Given the reaction $$\mathrm{N_2O_4(g) \rightleftharpoons 2 NO_2$(g)}$$ with $$K_c = 0.36 at$$ $$100^\circ C$$, and an initial $$[NO_2$] = 0.100\ \mathrm{M}$$, what is the correct setup for the equilibrium expression?

Accepted Answer

$$K_c = \frac{[NO_2$]^2}{[N_2O_4]}$$

Question 3

Which compound will precipitate first when potassium sulfate is added to a solution containing equal concentrations of $$\mathrm{Ba$$^{2+}$$}$$, $$\mathrm{Pb$$^{2+}$$}$$, and $$\mathrm{Ca$$^{2+}$$}$$ ions?

Accepted Answer

$$\mathrm{$$BaSO_4$$}$$

Question 4

A solution is prepared by mixing $$50.0\ \mathrm{mL} of$$ $$0.10\ \mathrm{M}$$ $$\mathrm{$$AgNO_3$$}$$ with $$50.0\ \mathrm{mL} of$$ $$0.10\ \mathrm{M}$$ $$\mathrm{NaCl}. $$Will a precipitate form? ($$K_{sp}$$ for $$\mathrm{AgCl} is$$ $$1.77 	imes 10$$^{-10}$$)

Accepted Answer

Yes, because $$Q \u003e K_{sp}.$$

Question 5

Which of the following combinations will create a buffer solution?

Accepted Answer

$$\mathrm{CH_3NH_2}$$ and $$\mathrm{CH_3NH_3Cl}$$

Question 6

Which of the following best describes the common ion effect?

Accepted Answer

The solubility of an ionic compound decreases in a solution containing a common ion.

Question 7

Calculate the molar solubility of $$\mathrm{$$PbCl_2$$} in $$pure water if $$K_{sp} = 1.17 	imes 10$$^{-5}$$.

Accepted Answer

$$1.48 	imes 10$$^{-2}$$\ \mathrm{M}$$

Question 8

Which of the following is the correct net ionic equation for the reaction between aqueous $$\mathrm{HI}$$ and aqueous $$\mathrm{Ba(OH)_2}$$?

Accepted Answer

$$2\mathrm{H^+(aq) + 2OH^-(aq) \rightarrow 2H_2O(l)}$$

Question 9

Which of the following is an example of a Lewis acid?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 10

A buffer solution is prepared by mixing $$0.50\ \mathrm{mol}$$ acetic acid ($$\mathrm{CH_3COOH}) $$and $$0.50\ \mathrm{mol}$$ sodium acetate ($$\mathrm{CH_3COONa}) in$$ $$1.0\ \mathrm{L} of $$water. If $$0.10\ \mathrm{mol} of $$HCl is added, what will happen to the pH?

Accepted Answer

The pH will decrease slightly.

Question 11

Which of the following best describes an amphiprotic substance?

Accepted Answer

A substance that can act as both an acid and a base.

Question 12

What is the pH of a $$2.0 	imes 10$$^{-3}$$\ \mathrm{M}$$ HCl solution?

Accepted Answer

2.00

Question 13

Which of the following is the correct name for $$\mathrm{H_2SO_3}$$?

Accepted Answer

Sulfurous acid

Question 14

Which of the following is the correct formula for nitric acid?

Accepted Answer

$$\mathrm{$$HNO_3$$}$$

Question 15

Which of the following best describes the effect of increasing temperature on the equilibrium constant $$K$$ for an exothermic reaction?

Accepted Answer

$$K$$ decreases

Question 16

Which of the following is a correct statement about the solubility product constant ($$K_{sp}$$)?

Accepted Answer

$$K_{sp} is $$the equilibrium constant for the dissolution of a solid in water.

Question 17

Which of the following is the correct balanced equation for the reaction of sodium amide ($$\mathrm{$$NaNH_2$$}) $$with methanol ($$\mathrm{CH_3OH}) in $$the context of Brønsted-Lowry acid-base theory?

Accepted Answer

$$\mathrm{NH_2$^- + CH_3OH \rightarrow NH_3$ + CH_3O^-}$$

Question 18

Which of the following is a conjugate acid-base pair?

Accepted Answer

$$\mathrm{H_2O}$$ and $$\mathrm{OH^-}$$

Question 19

Which of the following best describes the effect of adding ammonia to a solution containing $$\mathrm{AgCl(s)}$$?

Accepted Answer

The solubility of $$\mathrm{AgCl}$$ increases due to the formation of a complex ion.

Equilibria, Precipitation, and Acid-Base Chemistry: Study Notes

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