Madi Wright
8
[email protected]
CSAS Center – ML 402
CHEM 1002
Lectures:ElectronTransferReactions1–3
Textbook:Chapter17
Topics
• OxidationNumbers
• BalancingRedoxReactions
• Electrochemistry
• ActivitySeries
• CellShorthandNotation
• StandardCellPotential
Opener
Howdidthesecondmidtermgo?!
OxidationNumbers
Rule
Wednesdays
1:35-2:25pm
(5minutes)
(15minutes)
Examples
1.
2.
3.
4.
5.
6.
Madi Wright
8
[email protected]
CSAS Center – ML 402
CHEM 1002
Wednesdays
1:35-2:25pm
Examples
HAsO2(aq)+3H3O+(aq)+3e-→As(s)+5H2O(l)
HClO2àClO3-+HClO
BalancingRedoxReactions
Steps
(20minutes)
Madi Wright
8
[email protected]
CSAS Center – ML 402
CHEM 1002
Wednesdays
1:35-2:25pm
Example
Balancethefollowingreactioninabasicsolution:As(s)+ClO3¯(aq)→H3AsO3(aq)+HClO(aq)
ReductionPotentials
(10minutes)
Labelallofthefollowingpointsonthisgalvaniccell
F
A:
B:
E
C:
D:
A
B
E:
F:
C
D
G:
H:
G
H
Madi Wright
8
[email protected]
CSAS Center – ML 402
CHEM 1002
Wednesdays
1:35-2:25pm
LongAnswerQuestions (15minutes)
1.Writethebalancedoverallredoxreactionfortheelectrochemicalcelldenotedbythefollowing
shorthandnotation:Pt(s)|C2O42–(aq)|CO2(g)||Ag+(aq)|Ag(s)
2.Writetheshorthandnotationoftheelectrochemicalcell,whichhasthereaction:
3Fe2+(aq)+2Cr3+(aq)+24H2O(l)à3Fe(s)+2CrO42–(aq)+16H3O+(aq)
2.AGalvanicelectrochemicalcellisconstructedconsistingofthallium(Tl)metaldippinginan
aqueoussolutionthatis0.050MinTl+,connectedbyasaltbridgetoa0.50Maqueoussolutionof
HClincontactwithaPtelectrodeoverwhichH2gasisbubblingatp=0.90bar.
a)Writethebalancedredoxreaction
b)Determinethecellpotential(inV)at25oC
Closer
• 4weeksleft!
• Start,stop,andcontinue?
(5minutes)