SOLUBILITY PRODUCT CONSTANT

Tues March 26, 2013

Today we will:

• Check homework

• Learn how to write the expression for the solubility product constant

• Learn how to calculate concentrations of ions using the solubility product constant.

1 Answers to Solubility Product Constant Homework, section I +2 ­ 1. Mg(OH)2 (s) ↔ Mg (aq) + 2OH (aq) +2 ­2 2. CaCO3 (s) ↔ Ca (aq) + CO3 (aq) +2 ­ 3. PbCl2 (s) ↔ Pb (aq) + 2Cl2 (aq) + ­2 4. Ag2CO3 (s) ↔ 2Ag (aq) + CO3 (aq) +2 ­2 5. SrSO4 (s) ↔ Sr (aq) + SO4 (aq) +2 ­2 6. FeC2O4 (s) ↔ Fe (aq) + C2O4 (aq) +2 ­ 7. Zn(OH)2 (s) ↔ Zn (aq) + 2OH (aq) 8. CuSCN (s) ↔ Cu+(aq) + SCN­ (aq) +3 ­2 9. Al2(SO4)3 (s) ↔ 2Al (aq) + 3SO4 (aq) +2 ­ 10. Ba(NO3)2 (s) ↔ Ba (aq) + 2NO3 (aq) +2 ­ 11. Ni(OH)2 (s) ↔ Ni (aq) + 2OH (aq) +2 ­3 12. Ca3(PO4)2 (s) ↔ 3Ca (aq) + 2PO4 (aq) 13. AgSCN (s) ↔ Ag+(aq) + SCN­ (aq) +2 ­ 14. BaF2 (s) ↔ Ba (aq) + 2F (aq) +2 ­2 15. PbC2O4 (s) ↔ Pb (aq)+ C2O4 (aq) + ­2 16. Ag2CrO4 (s) ↔ 2Ag (aq) + CrO4 (aq) +2 –2 17. MgCO3 (s) ↔ Mg (aq) + CO3 (aq) 18. ZnS (s) ↔ Zn+2(aq) + S­2 (aq) +3 ­3 19. NiPO4 (s) ↔ Ni (aq)+ PO4 (aq) +3 ­ 20. Al(OH)3 (s) ↔ Al (aq) + 3OH (aq)

2 EQUILIBRIUM • Occurs when the forward and reverse reactions happen at an equal rate: there is no net change • Based on a specific temperature and pressure • The total amount of particles remains the same and therefore so does the concentration • • The concentration of a substance is denoted by the use of brackets around the formula [H2] • • The reaction is dynamic ‐ in constant motion

3 Dissolution and precipitation

• Remember: ionic substances separate into their ions in solution and become uniformly distributed in the sol’n • • Dissolution‐ the process in which an ionic solid dissolves in a polar liquid • • Can write an equation for dissociation • • Only dissociated substances are written as ions in equations • Must balance numerically and electrically

4 • Precipitation‐ the process in which ions leave a sol’n and regenerate an ionic solid • • Precipitate‐ solid formed • • Dissolution and precipitation are opposite process • • Solubility equilibrium: rate of dissolution= rate of precipitation

5 6 7 8 1. magnesium hydroxide 11. nickel (II) hydroxide 2. calcium carbonate 12. calcium phosphate 3. plumbous chloride 13. silver thiocyanate 4. silver carbonate 14. barium fluoride 5. strontium sulfate 15. plumbous oxalate 6. ferrous oxalate 16. silver chromate 7. zinc hydroxide 17. magnesium carbonate 8. cuprous thiocyanate 18. zinc sulfide

9. aluminum sulfate 19. nickel (III) phosphate

10. barium nitrate 20. aluminum hydroxid

9 10 11 1. magnesium hydroxide 11. nickel (II) hydroxide 2. calcium carbonate 12. calcium phosphate 3. plumbous chloride 13. silver thiocyanate 4. silver carbonate 14. barium fluoride 5. strontium sulfate 15. plumbous oxalate 6. ferrous oxalate 16. silver chromate 7. zinc hydroxide 17. magnesium carbonate 8. cuprous thiocyanate 18. zinc sulfide

9. aluminum sulfate 19. nickel (III) phosphate

10. barium nitrate 20. aluminum hydroxid

12 12. At 18°C, the concentration of lead ions in a saturated solution ­6 of plumbous oxalate is 5.23 x 10 M. What is the value of Ksp for plumbous oxalate?

13 14. At 25°C, the concentration of silver ions in a saturated solution of silver bromide is 7.07 x 10­7M. What is the value of Ksp for silver bromide?

14 15 8. What will be the equilibrium concentrations of silver and chromate ions in a saturated solution of ­12 silver chromate? (Ksp = 1.1 x 10 )

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