1. Lecture 6 Chemical Equlibria

2. Ca 2+ (NH 4 ) 2 C 2 O 4 K +, Mg 2+ K +. Mg 2+ CaC 2 O 4 precipitate Filtration Calcium separation CaC 2 O 4

3. Cu 2+ KIO 4 Fe 3+, MnO 4 - Cu 2+ Spectrophotometric determination Manganese determination Fe 3+, Mn 2+

4. Requirements: Yield 100% (± st.deviation of the method) A convenient procedure CaC 2 O 4 can be isolated and weighed Absorbance of MnO 4 - ion can be easily measured in visible light 99.99-100.01% for gravimetry (weighing) – 4 digits! 99.9-100.1% for spectrometry (absorbance) – 3 digits!

5. Chemical Equilibria aA + bB  cC+dD [A] Concentration related to standard state Standard: Liquid or solid – pure liquid or solid Gas -1 atm or 1 bar=10 5 Pa Solution - 1 M

6. Le Chatelier Principle Ca 2+ + H 2 C 2 O 4  CaC 2 O 4 + 2H + CO 2 + H 2 O  H + + HCO 3 -

7. PbI 2  Pb 2+ + 2 I - Pure solid Solubility Product Common Ion effect: more common ion – less solubility

8. Pb 2+ + 4 I -  PbI 4 2- Complex (Ion) Formation Stability constant

9. More I - - higher solubility

10. O H H H H 3 O + ion

11. More neighbors…

15. Weak acid element =O Weak conjugated base

16. + H 2 O + OH - base conjugated acid