Lecture 17. Electrode Potentials M

Lecture 17. Electrode Potentials M - pH Dependence of CaF2...

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Unformatted text preview: pH Dependence of CaF2 solubility pH Note the logarithmic ordinate. Daniel C. Harris, Exploring Chemical Analysis, 4th ed., W.H. Freeman and Company, New York, 2009. Freeman Fractional Composition Fractional Fractional composition of an acid HA Fractional with pKa = 5.0. with Daniel C. Harris, Exploring Chemical Analysis, 4th ed., W.H. Freeman and Company, New York, 2009. Freeman Fractional Composition Fractional H + ] [ A- ] [ Ka = Þ [HA] A- ] [ + HA] [H ] [ = Ka [A ] 1 = = [ A ] + [HA] 1 + [HA] 1+ A- ] [ or simplified : Ka = A ] + [HA] K a + [H + ] [ A- ] [ 1 H+] [ Ka Fractional Composition Fractional Fractional composition of an acid HA Fractional with pKa = 5.0. with Daniel C. Harris, Exploring Chemical Analysis, 4th ed., W.H. Freeman and Company, New York, 2009. Freeman Fractional Composition Fractional Example: Solubility of CaF2 in Water and 0.1 M NaCl Example: What is the difference in solubility of CaF2 in water and in 0.1 M NaCl? Daniel C. Harris, Exploring Chemical Analysis, 2nd ed., W.H. Daniel Freeman and Company, New York, 2001. Freeman Example: Solubility of CaF2 in Water and 0.1 M NaCl Example: What is the difference in solubility of CaF2 in water and in 0.1 M NaCl? ⇒Activity coefficients predict a 62% higher solubility in 0.1 M Activity NaCl than in pure water. ⇒Prove this to yourself! What to do if You Lack the Information to What Calculate Activity Coefficients? (1) Dilution of the sample with water. Why? (2) Dilution of the sample with a concentrated salt solution. Dilution Why? Why? (3) Standard addition: Addition of calibration standard into the Standard sample. Why? sample. Charge Balance Charge ∑ [positive charges] = ∑ [negative charges] Daniel C. Harris, Exploring Chemical Analysis, 2nd ed., W.H. Freeman and Company, New York, 2001. Freeman Mass Balance Mass The quantity of all species in a solution containing a The particular atom (or group of atoms) must equal the amount of that atom (or group) delivered to the solution. solution. Systematic Approach to Equilibrium Calculations Systematic Gary D. Christian, Analytical Chemistry, 6th ed., John Wiley & Sons, Inc., U.S.A., 2004. 2004. Electrode Potentials (Chapter 14) Electrode We will discuss the following chapters in the We order of 14 => 16 => 15 order Chapter 14: Electrode Potentials Chapter Redox Chemistry Zn + Cu2+ Zn2+ + Cuº Reducing Agent Oxidizing Agent Oxidation: loss of electrons Reduction: gain of electrons Oxidizing Agent: takes electrons Reducing Agent: gives electrons Galvanic Cells Galvanic oxidation reduction Why do we need the salt bridge? ...
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This note was uploaded on 04/06/2011 for the course CHEM 2011 taught by Professor Buhlman during the Spring '10 term at Minnesota.

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