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ANSWERS TO QUESTIONS:

1.

a. in distilled water:

Cu(OH)2(s) (( Cu2+(aq) + 2OH-(aq) Ksp Cu(OH)2

Keq = Ksp Cu(OH)2 = 2.2 x 10-20

b. + 6.0M H2C2O4

Cu(OH)2(s) (( Cu2+(aq) + 2OH-(aq) Ksp Cu(OH)2

H2C2O4 (( H+ + HC2O4- Ka1 H2C2O4

HC2O4- (( H+ + C2O42- Ka2 H2C2O4

Cu2+ + C2O42- (( CuC2O4 1/Ksp CuC2O4

2(OH- + H+ (( H2O) 1/K2w

Net Keq = (Ksp Cu(OH)2 x Ka1 x Ka2 )/Ksp CuC2O4

= 1.969 x 10-2

c. pinch of Zinc dust

Cu(OH)2(s) (( Cu2+(aq) + 2OH-(aq) Ksp Cu(OH)2

Zn2+((Zn(s)1

Cu(s)(( Cu2+1

Zn2+ + 2OH-(( Zn(OH)2 1/Ksp Zn(OH)2

Net Keq = Ksp Cu(OH)2/ Ksp Zn(OH)2

= 1.196 x 10-6

d. 6.0M HNO3

Cu(OH)2(s) (( Cu2+(aq) + 2OH-(aq) Ksp Cu(OH)2

2H+((H21

Cu(s)(( Cu2+1

2(OH- + H+ (( H2O) 1/K2w

Net Keq = Ksp Cu(OH)2/ K2w

= 2.2 x 10-6

e. 6.0M NH3

.Cu(OH)2(s) (( Cu2+(aq) + 2OH-(aq) Ksp Cu(OH)2

4(NH3(( NH4 + OH-) Kb NH3 x 4

Cu2+ + 4 NH3(( [Cu(NH3)4]2+1/Kf[Cu(NH3)4]2+

Net Keq = (Ksp Cu(OH)2 x (Kb NH3 x 4))/ Kf[Cu(NH3)4]2+

= 4.619 x 10-53

f. 1.0M Na3PO4

3(Cu(OH)2(s) (( Cu2+(aq) + 2OH-(aq)) Ksp Cu(OH)2

2(PO43- + H2O((HPO42- + H3O+) 1/Ka3 H3PO4

2(HPO43- + H2O((H2PO42- + H3O+) 1/Ka2 H3PO4

2(H2PO43- + H2O((H3PO42- + H3O+) 1/Ka1 H3PO4

3Cu2+ + 2PO43-(( Cu3(PO4)21/Ksp Cu3(PO4)2

Net Keq = (Ksp Cu(OH)2 x 3)/( Ka3 H3PO4 x Ka2 H3PO4 x Ka1 H3PO4 x Ksp Cu3(PO4)2)

= 1.153 x 1021

g. 0.10M Cu(NO3)2

Cu(OH)2(s) (( Cu2+(aq) + 2OH-(aq) Ksp Cu(OH)2

Keq = Ksp Cu(OH)2 = 2.2 x 10-20

2. a. none

b. test tubes 1-5

c. test tubes 3, 5 and 6

d. 2, 4 and 7

e. 2, 4 and 7

f. 3, 5 and 6

3. Part B of the experiment was the Nacl(s) equilibrium wherein 3 test tubes with a milliliter of a saturated NaCl was added with some reagents. The first one was...
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