Upload
michael-harding
View
216
Download
0
Tags:
Embed Size (px)
Citation preview
Unit 10 - Chpt 18 - Electrochemistry
• Balance Redox equations
• HW set1: Chpt 18 - pg. 862-865 # 30, 32 - Due Tues. Apr 20
• HW set2: Chpt 18 - pg. 862-865 # 40, 44, 50, 54, 60, 65, 74 - Due Fri. Apr 23
Workbook Lesson pkt
• Lesson 13 - Formal Oxidation number assignments - with examples and homework
• Lesson 28 - Balancing Redox Reactions with examples and homework
Sect 18.2 - 18.5 (slides provided)
Galvanic Cell schematic
Oxidation occurs at anode (vowels)
Reduction occurs at cathode (consonants)
Oxidation produces electrons, so current flows from anode to cathode.
Types of cells
Standard Hydrogen cell platinum electrodemetal electrodes
Cell Potential & Nernst Equation
• Galvanic Cell Potentials - free energy
Go = -nFEo F is Faraday constant 96485 C/mol e-
n = moles of e- from balanced Redox eqn
• Concentration Cell Potentials
G = Go + RTlnQ or K if Ecell = 0
Cell Potential & Nernst Equation
G = Go + RT ln Q
-nFE = -nFEo +RT ln Q
E = Eo - RT/nF ln Q
E = Eo - 0.0592/n log Q
So E of a cell with concentrations not equal to 1 M is the std cell potential with the correction
remember to know electrons transferred in Redox
Equilibrium, K constant
E = Eo - RT/nF log Q
At equilibrium Ecell = 0 and Q = K
0 = Eo - 0.0592/n log K
log K = nEo / 0.0592
K example
• Example 18.10 pg 841
Battery - Dry Cell