AP Chemistry Name

AP Chemistry Name : Worksheet : Obj. 26-33 Date :

_____ 1. In which of the following aqueous solutions would you expect AgBr to have the lowest solubility?

a. pure water b. 0.20M NaBr c. 0.10M AgNO3 d. 0.15M KBr e. 0.10M LiBr

_____ 2. In which of the following aqueous solutions would you expect AgBr to have the highest solubility?

a. 0.10M LiBr b. 0.10M AgNO3 c. 0.20M NaBr d. 0.15M KBr e. pure water

_____ 3. Which one of the following is not amphoteric?

a. Al(OH)3 b. Ca(OH)2 c. Cr(OH)3 d. Zn(OH)2 e. Sn(OH)2

_____ 4. For which salt should the aqueous solubility be most sensitive to pH?

a. Ca(NO3)2 b. CaF2 c. CaCl2 d. CaBr2 e. CaI2

_____ 5. Which below best describe(s) the behavior of an amphoteric hydroxide in water?

a. With conc. aq. NaOH, its suspension dissolves. b. With conc. aq. HCl, its suspension dissolves. c. With conc. aq. NaOH, its clear solution forms a precipitate. d. With conc. aq. HCl, its clear solution forms a precipitate. e. With both conc. aq. NaOH and conc. aq. HCl, its suspension dissolves.

_____ 6. Precipitates can be dissolved, in general,

a. never, once they form. b. by adding an additional amount of one of the constituent ions to the solution. c. by complexing one of the constituent ions in a soluble form. d. both "by adding an additional amount of one of the constituent ions to the solution" and "by complexing one of the constituent ions in a soluble form" are true. e. "never, once they form", "by adding an additional amount of one of the constituent ions to the solution", and "by complexing one of the constituent ions in a soluble form" are all true.

_____ 7. You have two salts, AgX and AgY, with very similar Ksp values. You know that Ka for HX is much greater than Ka for HY. Which salt is more soluble in acidic solution?

a. AgX b. AgY c. They are equally soluble in acidic solution. d. Cannot be determined by the information given.

_____ 8. For a solution equimolar in HCN and NaCN, which statement is false?

a. This is an example of the common ion effect. b. The [H+] is larger than it would be if only the HCN was in solution. c. The [H+] is equal to the Ka. d. Addition of more NaCN will shift the acid dissociation equilibrium of HCN to the left. e. Addition of NaOH will increase [CN-] and decrease [HCN]. 9. Two drops of indicator HIn (Ka = 1.0 x 10-9), where HIn is yellow and In- is blue, are placed in 100.0 mL of 0.10 M HC1.

a. What color is the solution initially?

b. The solution is titrated with 0.10 M NaOH. At what pH will the color change (yellow to greenish yellow) occur?

c. What color will the solution be after 200.0 mL of NaOH has been added?

10. Which of the indicators in Fig. 15.8 could be used for the titrations in the following?

a. HCl and NaOH

b. Ca(OH)2 and HClO4 (pH = 8.79 at eq. pt.)

11. Which of the indicators in Fig. 15.8 could be used for the titrations in the following?

a. HC3H5O3 and NaOH(pH = 8.28 at eq. pt.)

b. NH3 and HCl (pH = 5.28 at eq. pt.)

12. Estimate the pH of a solution in which crystal violet is yellow and methyl orange is red. (See Fig. 15.8.)

13. A solution has a pH of 9.0. What would be the color of the solution if each of the following indicators were added? (See Fig. 15.8.)

a. Methyl orange

b. Alizarin

c. Bromcresol green

d. Thymol blue 14. Write balanced equations for the dissolution reactions and the corresponding expressions for the solubility products of the following.

a. AgC2H3O2

b. A1(OH)3

c. Ca3(PO4)2

15. Use the following data to calculate the Ksp value for each solid.

-5 a. The solubility of CaC2O4 is 4.8 x 10 mol/L.

-5 b. The solubility of BiI3 is 1.32 x 10 mol/L. 2+ -2 16. The concentration of Pb in a solution saturated with PbBr2 is 2.14 x 10 M. Calculate Ksp for PbBr2.

17. Calculate the solubility of each of the following compounds in moles per liter. Ignore any acid-base properties.

-18 a. Ag3PO4, Ksp = 1.8 x 10

-9 b. CaCO3, Ksp = 8.7 x 10

-18 2+ c. Hg2Cl2, Ksp = 1.1 x 10 (Hg2 is the cation in solution.)

-32 18. Calculate the molar solubility of A1(OH)3, Ksp = 2 x 10 .

19. For each of the following pairs of solids, determine which solid is least soluble.

-11 -5 a. CaF2(s), Ksp = 4.0 x l0 or BaF2(s), Ksp = 2.4 x 10

-32 -22 b. Ca3(PO4)2(,s), Ksp = 1.3 x 10 , or FePO4(s), Ksp =l.0 x 10

-38 20. Calculate the solubility (in moles per liter) of Fe(OH)3 (Ksp = 4 x 10 ) in each of the following.

a. Water (assume pH is 7.0 and constant)

b. A solution buffered at pH = 5.0

c. A solution buffered at pH = 11.0 -32 21. Calculate the solubility of solid Ca3(PO4)2 (Ksp = 1.3 x 10 ) in a 0.20 M Na3PO4 solution. 22. Which of the following substances show increased solubility as the pH of the solution becomes more acidic? Write equations for the reactions that occur to increase the solubility.

a. Ag3PO4

b. CaCO3

c. Hg2Cl2

d. SrSO4

23. Will a precipitate form when 75.0 mL of 0.020 M BaCl2 and 125 mL of 0.040 M Na2SO4 are mixed -9 together? (Ksp for BaSO4 = 1.5 x 10 )

+ 2- 2+ - 24. Calculate the final concentrations of K (aq), C2O4 (aq) Ba (aq), and Br (aq) in a solution prepared by -8 adding 0.100 L of 0.200 M K2C2O4 to 0.150 L of 0.250 M BaBr2. (For BaC2O4, Ksp = 2.3 x 10 .)

-5 25. A solution contains 1.0 x 10 M Na3PO4. What is the minimum concentration of AgNO3 that would cause -18 precipitation of solid Ag3PO4 (Ksp = 1.8 x 10 )?

Answers : 9a. yellow 9b. 8.0 9c. blue 10a. Phenol red is one possibility 10b. phenolphthalein is one poss. 11a. phenolphthalein 11b. bromcresol green 12. pH < 0.5 13a. yellow 13b. orange 13c. blue 2+ 3- -9 -19 -5 13d. bluish-green 14c. Ca3(PO4)2  3Ca + 3PO4 15a. 2.3 x 10 15b. 8.20 x 10 16. 3.92 x 10 -5 -5 -7 -11 17a. 1.6 x 10 M 17b. 9.3 x 10 M 17c. 6.5 x 10 M 18. 2 x 10 M 19a. CaF2 19b. FePO4 20a. 4 -17 -11 -29 -11 x 10 M 20b. 4 x 10 M 20c. 4 x 10 M 21. 2.3 x 10 M 22. Ag3PO4, (Ag3PO4(s) + H+(aq)  3 2- -4 2- Ag+(aq) + HPO4 (aq)) CaCO3 and SrSO4 23. yes, Q = 1.9 x 10 > Ksp 24. [K+] = 0.160 M, [C2O4 ] = 3.3 x 10-7 M, [Ba2+] = 0.0700 M, [Br -]= 0.300 M 25. [Ag+] > 5.6 x 10-5 M