Outline: 4/11/07

Today: Finish Chapter 19

Coulomb Calculations Redox Applications

CAPA 18 due tonight… CAPA 19 due Friday… Special seminar Thursday pm Special seminar Friday 4pm Pick up Quiz 8 – from me Pick up grade summary – in front

Outline: 4/11/07

Today: Finish Chapter 19

Coulomb Calculations Redox Applications

CAPA 18 due tonight… CAPA 19 due Friday… Special seminar Thursday pm Special seminar Friday 4pm Pick up Quiz 8 – from me Pick up grade summary – in front

SC 1019

6-8pm

Panel @ 8pm

Outline: 4/11/07

Today: Finish Chapter 19

Coulomb Calculations Redox Applications

CAPA 18 due tonight… CAPA 19 due Friday… Special seminar Thursday pm Special seminar Friday 4pm Pick up Quiz 8 – from me Pick up grade summary – in front

Quiz #7

Average = 8.2 Average = 8.2 Good!Good!

Chapter 19 practice problems:

19.1, 19.3, 19.5, 19.9, 19.11, 19.13, 19.15, 19.1, 19.3, 19.5, 19.9, 19.11, 19.13, 19.15, 19.17, 19.19, 19.21, 19.23, 19.25, 19.27, 19.17, 19.19, 19.21, 19.23, 19.25, 19.27, 19.33, 19.35, 19.37, 19.39, 19.41, 19.45, 19.33, 19.35, 19.37, 19.39, 19.41, 19.45, 19.49, 19.53, 19.55, 19.63, 19.65, 19.67, 19.49, 19.53, 19.55, 19.63, 19.65, 19.67, 19.69, 19.73, 19.77, 19.81, 19.83, 19.8519.69, 19.73, 19.77, 19.81, 19.83, 19.85

Grade Summary Go over grade summary sheetGo over grade summary sheet 8 quizzes / 70 pts (drop one)8 quizzes / 70 pts (drop one) 4 pts/seminar report extra credit4 pts/seminar report extra credit CAPA through 17; w/out a few handinsCAPA through 17; w/out a few handins Exam 1, Exam 2 added at 20 or 15%Exam 1, Exam 2 added at 20 or 15% Final exam 60% or 75% or 90%...Final exam 60% or 75% or 90%...

Please see me if there is an data entry errorPlease see me if there is an data entry error

Finish Chapter 19: Current = charge/time 1 Ampere = 1 Coulomb / second

Calculational Example: A lead-acid battery: PbO2+HSO4

+2H++Pb 2PbSO4 +2H2O

Assume 250 g of PbO2 and that this battery supplies 6 Amps until it dies; how long will it last?

250 g PbO2 × 1 mol/ 239.2 g =

1.045 mol PbO2

2.090 mol e × 96485 C/mol = 201654

C (time) × (6 C/sec) = 201654 C

time = 3361 sec = 9.34 hours

PbO2 PbSO4 (+4 +2) : 2e

1.045 mol PbO2 × 2 mol e / mol PbO2=

2.090 mol e

Problem #3 - Worksheet #12:

Current calculation…. Which equations? What is the limiting reagent? How many moles? How much time at 0.2 mA?

Worksheet #12 HgO Hg (+2 0) : 2e

Zn ZnO (0 +2) : 2e

Moles of everything: 1 g HgO × 1mol/216.6g = 0.00462 mol 1 g Zn × 1mol/65.4g = 0.01530 mol What is the limiting reagent? HgO

Moles of electrons: 0.00462l mols HgO × 2 mols e/mol HgO

Moles e to Coulombs conversion: 0.00924 mol e × 96485 C/mol e = 891.5 C = 891.5 Amp . sec How long?

891.5 Amp . sec = (x sec)(0.2×103 Amp) x = 4.46×106 sec = 1238 hours

Practice! Practice! Practice! Practice!

Redox applications: Batteries Fuel Cells Electroplating Ore Extraction/Mining Rust Protection Metallurgy/Alloys Electrolysis

Read pp. 847 - 857 in textbook