Chemistry 12 Test 2001

 

1. Consider the following experiment:

 

 

1.0 mL 0.20 M Ag+      +          an unknown solution     →        precipitate

 

1.0 mL 020 M Sr2+      +          an unknown solution     →        no precipitate

 

The unknown solution could contain

 

A         0.20 M OH-    low with Ag+ and high with Sr2+

            B          0.20 M NO3-

            C         0.20 M PO43-

            D         0.20 M SO42-

 

2. A compound has a solubility of 7.1  x  10-5 M at 25 oC. The compound is

 

            A         CuS

            B          AgBr

            C         CaCO3            square the solubility

            D         CaSO4

 

3. A saturated solution of NaCl contains 36.5 g of solute in 0.100 L of solution. The solubility of the compound is

           

            A         0.062 M

            B          1.60 M

            C         3.65 M

            D         6.24 M

 

4. Calculate the [Li+] in 200.0 mL of 1.5 M Li2SO4.

 

            A         0.30 M

            B          0.60 M

            C         1.5 M

            D         3.0 M  Do not divide by L

 

5. The Ksp expression for a saturated solution of Mg(OH)2 is

 

            A         Ksp  =  [Mg2+][OH-]2

                                      [Mg(OH)2]

 

            B         Ksp  =  [Mg2+][OH-]2

 

            C         Ksp  =  [Mg2+][OH-]

 

            D         Ksp  =  [Mg2+][2OH-]2

 

 

 

 

6. Consider the following saturated solution solutions

 

                        CuSO4             BaSO4             CaSO4

 

The order of cation concentration, from highest to lowest, is

 

            A         [Ba2+]               >          [Ca2+]              >          [Cu2+]

            B          [Ca2+]              >          [Cu2+]              >          [Ba2+]

            C         [Cu2+]              >          [Ca2+]              >          [Ba2+]  largest to smallest Ksp

            D         [Cu2+]              >          [Ba2+]               >          [Ca2+]

 

7. When 1.0  x  10-3 moles of CuCl2(s) are added to 1.0 L of 1.0  x  10-3 M IO3-, the

 

            A         Trial Ksp > Ksp and a precipitate forms

            B          Trial Ksp < Ksp and a precipitate forms

C         Trial Ksp > Ksp and no precipitate forms

D         Trial Ksp < Ksp and no precipitate forms

 

8. The solubility of CdS = 2.8 x 10-14 M. The value of the Ksp is

 

            A         7.8  x  10-28      Square the solubility

            B          2.8  x  10-14

            C         5.6  x  10-14

            D         1.7  x  10-7

 

9. The ion concentrations in 0.25 M Al2(SO4)3 are

 

                        [Al3+]               [SO42-]

 

            A         0.25 M             0.25 M

            B         0.50 M                        0.75 M

            C         0.75 M             0.50 M

            D         0.10 M             0.15 M

 

10. Which of the following will not produce a precipitate when equal volumes of 0.20 M solutions are combined?

 

            A         KOH and CaCl2

            B          Zn(NO3)2 and K3PO4

            C         Sr(OH)2 and (NH4)2S Both have high solubility

            D         Na2SO4 and Pb(NO3)2

 

11. Consider the following equilibrium: Mg(OH)2(s)  ⇄  Mg2+(aq)  +  2OH-(aq)

           

A compound that can be added to cause a shift to the right is

 

A         NaOH

            B         HCl     Acids react with OH-

            C         Sr(OH)2

            D         Mg(OH)2

 

12. If the trial ion product for AgBrO3 is calculated to be 1.0  x  10-7, then

 

            A         a precipitate forms because the trial ion product > Ksp

            B          a precipitate forms because the trial ion product < Ksp

            C         no a precipitate forms because the trial ion product > Ksp

            D         no a precipitate forms because the trial ion product < Ksp

 

13.Which of the following will dissolve in water to produce a molecular solution?

 

            A         CaCl2

            B          NaOH

            C         CH3OH           One of these things is not kike the other

            D         Sr(OH)2

 

14. In a solubility equilibrium, the

 

            A         rate of dissolving equals the rate of crystallization

            B          neither dissolving or crystallization occurs

            C         concentration of solute and solvent are equal

            D         mass of dissolved solute is greater than the mass of the solution

 

15. The maximum [SO42-] that can exist in 1.0  x  10-3 M Ca(NO3)2 without a precipitate forming is

 

            A         7.1  x 10-5 M

            B          1.0  x 10-3 M

            C         8.4  x 10-3 M

            D         7.1  x 10-2 M

 

16. When equal volumes of 0.20 M CuSO4(aq) and 020 M Li2S(aq)  are combined, the complete ionic equation is

            A         Cu2+(aq) +          S2-(aq)                 →        CuS(s)

            B          CuSO4(aq)         +          Li2S(aq)  →        CuS(s)               +          Li2SO4(s)

            C         Cu2+(aq)  +  SO42-(aq)  +  2Li+(aq)   + S2-(aq)                 →   Li2SO4(aq)               +          CuS(s)

            D         Cu2+(aq)              +  SO42-(aq)  +  2Li(aq)  +  S2-(aq)  →   CuS(s)     +     2Li+(aq)      + SO42-(aq) 

 

17. Consider the solubility equilibrium:   CaCO3(aq)  ⇄  Ca2+(aq)  +  CO32-(aq)

 

An additional piece of solid CaCO3 is added to the equilibrium above. The rate of dissolving and the rate of crystallization have

 

                                    Rate of Dissolving                     Rate of crystallization

 

            A                     increases                                increases

            B                      increases                                  not changed

            C                     not changed                              increased

            D                     not changed                              not changed                 

 

 

 

 

 

18. At 25 oC, which of the following compounds would dissolve to form a saturated solution with the greatest [Pb2+]?   

 

            A         PbI2

            B         PbCl2               largest Ksp

            C         PbBr2

            D         Pb(IO3)2

 

19. Consider the following anions:

 

            I           10.0 mL of 0.20 M Cl-

            II          10.0 mL of 0.20 M OH-

            III        10.0 mL of 0.20 M SO32-

 

When 10.0 mL of 0.20 M Pb(NO3)2 are added to each of the above, precipitates form in

 

            A         I and II only

            B          I and III only

            C         II and III only

            D         I, II, and III

 

20. Which of the following units could be used to describe solubility?

 

            A         g/s

            B         g/L

            C         M/L

            D         mol/s

 

21. The solubility of SnS is 3.2 x 10-3 M. The value of the Ksp is

 

            A         1.0  x  10-5       square the solubility

            B          3.2  x  10-3

            C         6.4  x  10-3

            D         5.7  x  10-2

 

22. Silver chloride, AgCl, would be least soluble in

 

            A         1.0 M HCl

            B          1.0 M NaNO3

            C         1.0 M ZnCl2

            D         1.0 M AgNO3 

 

23. The solubility of SrF2 is

 

            A         4.3  x  10-9

            B          6.6  x  10-5

            C         1.0  x  10-3       square-root the Ksp

            D         1.6  x  10-3

 

 

 

 

24. The Ksp expression for a saturated solution of AgCO3 is

 

            A         Ksp  =  [Ag2+][CO32-]

            B         Ksp  =  [Ag+]2[CO32-]

            C         Ksp  =  [2Ag+][CO32-]

            D         Ksp  =  [2Ag+]2[CO32-]

 

25. How many moles of solute are dissolved in 200.0 mL of a saturated solution of FeS?

 

            A         1.2  x  10-19

            B          6.0  x  10-19

            C         1.5  x  10-10

            D         7.7  x  10-10

 

26. A solution contains both Ag+ and Mg2+ ions. During selective precipitation, these ions are removed one at a time by adding

 

            A         I- followed by OH-

            B          OH- followed by S2-

            C         SO42- followed by Cl-

            D         NO3- followed by PO43-

 

27. Which of the following does not define solubility?

 

            A         the concentration of solute in a saturated solution

            B         the moles of solute dissolved in a given amount of solution

            C         the maximum mass of solute that can dissolve in a given amount of solution

            D         the minimum amount of solute required to produce one litre of saturated solution

 

28. The ion concentrations in 0.25 M Al2(SO4)3 are

 

                                    [Al3+]               [SO42-]

 

            A                     0.25 M             0.25 M

            B                     0.50 M                        0.75 M

            C                     0.75 M             0.50 M

            D                     0.10 M             0.15 M

 

29. Which of the following will not produce a precipitate when equal volumes of 0.20 M solutions are combined?

 

            A         KOH and SrCl2

            B          Zn(OH)2 and K3PO4

            C         Zn(OH)2 and (NH4)2S

            D         Na2SO4 and Pb(NO3)2

 

30. What is observed when H2SO4 is added to a saturated solution of CaSO4?

 

            A         CaSO4(s) dissolves

            B          the [Ca2+] increases

            C         bubbles of H2 are given off

            D         additional CaSO4 precipitates

31. The solubility of CdS is 2.8  x  10-14 M. The value of the Ksp is

 

            A         7.8  x  10-28                 

            B          2.8  x  10-14

            C         5.6  x  10-14

            D         1.7  x  10-7

 

32. Consider the following solutions: 0.10 M Cl-            0.10 M Br-       0.10 M IO3-     0.10 M BrO3-

 

Equal moles of AgNO3 are added to each solution. It is observed that a precipitate forms in all but one solution. Which solution does not form a precipitate?

 

            A         Cl-

            B          Br-

            C         IO3-

            D         BrO3-    highest Ksp

 

33. Consider the following equilibrium: 2O3(g)     ⇄   3O2(g)    Keq  =  65

 

Initially, 0.10 mole O3 and 0.10 mole of O2 are placed in a 1.0 L container. Which of the following describes the changes in concentrations as the reaction proceeds to equilibrium?

 

                        [O3]                             [O2]

 

            A         decreases                     decreases

            B         decreases                   increases

            C         increases                      decreases

            D         increases                      increases

 

34.Consider the following potential energy diagram for the reversible reaction.

 

 

 

 

 

 

 

 

 

 

 

 

 


                                                Activation Energy (kJ)              ΔH (kJ)

 

A                     10                                                        -20

            B                      10                                                        -30

            C                     30                                                        +10

            D                     20                                                        +30

 

 

35. Increasing the temperature of a reaction increases the rate by

 

            I           increasing frequency of collision

            II          increasing the kinetic energy of collision

            III        decreasing the potential energy of collision

 

            A         I only

            B         I and II only

            C         II and III only

            D         I, II, and III

 

36. What is the Keq expression for the following equilibrium?

 

Fe (s)   +  4H2O(g)  ⇄  Fe3O4(s)  +  4H2(g)

 

            A         Keq  =  [H2]4

           

B          Keq  =  [H2]

                                    [H2O]

 

C         Keq  =  [H2]4

                                                [H2O]4

           

D         Keq  =   [Fe3O4][H2]4

                                                   [Fe]3[H2O]4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Subjective

 

1. Write the net ionic equation representing the reaction that occurs when 50.0 mL of 0.20 M ZnSO4 and 50.0 mL 0.20 M BaS are combined.

 

 

ZnSO4(aq)   +   BaS(aq)   →  BaSO4(s)   +  ZnS(s)

 

 

Zn2+   +   SO42-    +   Ba2+   +   S2-    →   BaSO4(s)     +      ZnS(s)   

 

 

Zn2+   +   SO42-    +   Ba2+   +   S2-    →   BaSO4(s)     +      ZnS(s)   

 

 

 

 

 

 

 

 

 

 

 

2. A 100.0 mL sample of 0.600M Ca(NO3)2 is diluted by adding 400.0 mL of water. Calculate the concentrations of all of the ions.

 

 

 

Ca(NO3)2        ⇄        Ca2+     +          2NO3-

 

 

(100)    0.600 M                      0.120 M          0.240 M

(500)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3. When 1.00 L of CaF2 was evaporated to dryness, 2.66  x  10-2 g of residue was formed. Calculate the Ksp.

 

 

 

Molarity  =     2.66  x  10-2 g  x  1 mole

                                                    78.1 g          =   3.406  x  10-4 M

                                    1.00 L

 

 

 

            CaF2                            ⇄                    Ca2+                 +                      2F-

 

3.406  x  10-4 M                                  3.406  x  10-4 M                      6.812  x  10-4 M

           

 

 

 

            Ksp     =  (3.406  x  10-4 )(6.812  x  10-4) 2

 

                        =   1.58  x  10-10

 

 

 

 

 

 

4. A maximum of 0.60 g Pb(NO3)2 can be added to 1.5 L of 0.100 M NaBr(aq) without forming a precipitate. Calculate the [NaBr].

 

 

 

Molarity  =     0.60 g  x  1 mole

                                        331.2 g        =   0.001208 M

                                    1.5 L

 

 

 

            PbBr2                          ⇄                    Pb2+                 +                      2Br-

 

                                                                        0.001208 M                            0.100 M

 

 

                                    Ksp  =  [Pb2+][Br-]2

 

                                    Ksp  =  [0.001208][0.100]2

 

                                    Ksp  =  1.2  x  10 -5

 

 

 

5. Consider the following solutions at 25 oC

 

 

 

 

 

 

 

 

 

 

 

 


            saturated AgCl(aq)                                                          saturated Ag2CO3(aq)

 

Using calculations, identify the solution with the greater [Ag+].

 

 

            AgCl(s)    ⇄    Ag+   +              Cl-                                Ag2CO3(s)           ⇄      2Ag+    +          CO32-

 

            x                      x                      x                                  x                                  2x                    x

 

 

            Ksp     =          x2                                                                     Ksp  =  4x3

 

            1.8  x  10-10  =  x2                                                                    8.5  x  10-12  =  4x3

 

            x          =          1.3  x  10-5 M                                                  x          =          1.286  x  10-4 M

 

            [Ag+]  =  1.3  x  10-5 M                                                           [Ag+]  =  2x   =   2.6  x  10-4 M

 

                                                                                                            Greater