Chem 12
Web Review Solubility
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A. Concepts.
1. Describe the relationship between the rate of dissolving solid and rate of crystallization:
a) a saturated solution and some solid
b) an unsaturated solution and some solid
c) a supersaturated solution
2. Write the equilibrium expression and Ksp equation for Fe2O3.
3. Write the net ionic equation for the reaction between Al(NO3)3 and Na2CO3. Note the difference between this equation and the last one.
4. Mg+2, Sr+2, Ca+2 and Be+2 are possibly in a solution. The solution reacts with Na2SO4 but not NaOH or Na2S. What cations are in the solution?
5. A solution contains SO4-2 or OH- or both. It reacts with Zn(NO3)2and Sr(NO3)2, What anions are in the solution?
6. Ag2CO3(s) ==== 2Ag+ + CO3-2 Describe the effect on the solubility of Ag2CO3 for each change below:
a) add Ag2CO3 b) add water c) add NaCl d) add Pb(NO3)2 e) add Na2CO3 f) add AgNO3.
7. If the trial Ksp = 1.7x10-7 and the Ksp = 3.8x10-7 will a precipitate occur?
8. For a saturated solution of Fe(OH)3 the [OH-] is found to be 1.3x10-4M. Calculate the [Fe+3] and the solubility of the salt in mols/L.
Common ion effect
9. Consider the equilibrium that exists in a saturated solution of PbCl2. Write the equilibrium expression. If the equilibrium shifts to the right, what affect does this have on the solubility? Describe how the addition of each of the following will affect the solubility of PbCl2.
a) AgNO3 b) NaCl c) Na2S d) H2O e) NaNO3 f) Pb(NO3)2 g) Beer
10. If the reaction is endothermic, how does the Ksp and the solubility change if the temperature is increased? What is the only way to change the Ksp?
B. Calculations
Titration
1. In a titration 250ml of a .200M AgNO3 solution was used to precipitate out all of the Cl- in a 500 ml sample. Calculate [Cl-].
2. In a titration 26.5ml of .100M Pb(NO3)2 was used to precipitate out all of the I- in a 3.00ml sample of water. Calculate [I-].
Ksp
3. Co(OH)2 Solubility = 3.0x10-3 g/L Ksp=?
4. Ag2C2O4 Solubility = 8.3x10-4 M Ksp=?
Solubility
5. SrF2 Ksp = 2.8 x 10-9 Solubility in (M) = ?
6. Cu(IO3)2 Ksp = 1.4 x 10-7 Solubility (g/L) = ?
Maximum Ion Concentration
7. Calculate the maximum concentration of OH- that can exist in a .200M Ca(N03)2 solution. Ksp (Ca(OH)2) = 2.8 x 10-8
8. Calculate the maximum concentration of CO3-2 that can exist in a .500M Fe(NO3)3 solution. Ksp (Fe2(CO3)3) = 2.8 x 10-14
Trial Ksp
9. Will a precipitate form if 200ml .0020M Ca(NO3)2 is mixed 300ml of .0030M NaOH?
Ksp ( Ca(OH)2 ) = 1.9 x 10-9
10. Will a precipitate form if 25.0ml of .0020M Pb(NO3)2 is mixed with 25.0ml of .040M NaBr.
Ksp (PbBr2) = 4.8 x 10 -5
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