AP Chemistry: Chapter 5-6 Student...
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Transcript of AP Chemistry: Chapter 5-6 Student...
AP Chemistry—WPHS AP Chem Page 1 3/24/2011
AP Chemistry: Student Notes
Objectives
17.1a: Review Redox
Assign Oxidation Numbers to the following:
a. HNO3
b. PbSO4
c. (NH4)2Ce(SO4)3
Balance the following in medium
Al (s) + MnO4- (aq) Al
3+ (aq) + Mn
2+ (aq)
Balance the following in a basic medium
Mg (s) + OCl- (aq) Mg(OH)2 (s) + Cl
- (aq)
17.1a: Review of Redox
17.1: Galvanic Cells
17.2: Standard Reduction Potentials
17.3: Cell Potential and Equilibrium
17.4: The Nernst Equation
17.5--6: Batteries & Corrosion
17.6: Electrolysis
AP Chemistry—WPHS AP Chem Page 2 3/24/2011
Balance the following Redox Reaction: The big nasty problem
K4Fe(CN)6 + KMnO4 + H2SO4 KHSO4 + Fe2(SO4)3 + MnSO4 + HNO3 + CO2 +H2O
AP Chemistry—WPHS AP Chem Page 3 3/24/2011
17.1: Galvanic Cells
Review of Redox Reactions
Oxidation: _______________________
Reduction: ___________________________
How to make a __________________ _____________________ (gc)
Which is a _____________________
You need to make separate __________________ for each _____________ reaction.
The problem with this cell is …..
AP Chemistry—WPHS AP Chem Page 4 3/24/2011
If you put a ______________ ________________ the cell will produce ___________ for a long time.
AP Chemistry—WPHS AP Chem Page 5 3/24/2011
Galvanic Cells: Label All parts
What happens when one of the electrodes is not a metal?
AP Chemistry—WPHS AP Chem Page 6 3/24/2011
17.2: Standard Reduction Potentials
Half-reaction E° (V)
Li+ + e
− ⇄ Li(s) −3.0401
Cs+ + e
− ⇄ Cs(s) −3.026
Rb+ + e
− ⇄ Rb(s) −2.98
K+ + e
− ⇄ K(s) −2.931
Ba2+
+ 2 e− ⇄ Ba(s) −2.912
Sr2+
+ 2 e− ⇄ Sr(s) −2.899
Ca2+
+ 2 e− ⇄ Ca(s) −2.868
Na+ + e
− ⇄ Na(s) −2.71
Mg2+
+ 2 e− ⇄ Mg(s) −2.372
Al(OH)4− + 3 e−
⇄ Al(s) + 4 OH− −2.33
Al(OH)3(s) + 3 e− ⇄ Al(s) + 3OH
− −2.31
Al3+
+ 3 e− ⇄ Al(s) −1.66
Ti3+
+ 3 e− ⇄ Ti(s) −1.21
Mn2+
+ 2 e− ⇄ Mn(s) −1.185
2 H2O + 2 e− ⇄ H2(g) + 2 OH
− −0.8277
Zn2+
+ 2 e− ⇄ Zn(s) −0.7618
Cr3+
+ 3 e− ⇄ Cr(s) −0.74
PbO(s) + H2O + 2 e− ⇄ Pb(s) + 2 OH
− −0.58
H3PO2(aq) + H+ + e
− ⇄ P(white[9]) + 2 H2O −0.508
H3PO3(aq) + 2 H+ + 2 e−
⇄ H3PO2(aq) + H2O −0.499
H3PO3(aq) + 3 H+ + 3 e−
⇄ P(red)[9]
+ 3H2O −0.454
Fe2+
+ 2 e− ⇄ Fe(s) −0.44
2 CO2(g) + 2 H+ + 2 e−
⇄ HOOCCOOH(aq) −0.43
Cr3+
+ e− ⇄ Cr
2+ −0.42
AP Chemistry—WPHS AP Chem Page 7 3/24/2011
Cd2+
+ 2 e− ⇄ Cd(s) −0.40
Cu2O(s) + H2O + 2 e− ⇄ 2 Cu(s) + 2 OH
− −0.360
PbSO4(s) + 2 e− ⇄ Pb(s) + SO4
2− −0.3588
PbSO4(s) + 2 e− ⇄ Pb(Hg) + SO4
2− −0.3505
Co2+
+ 2 e− ⇄ Co(s) −0.28
H3PO4(aq) + 2 H+ + 2 e−
⇄ H3PO3(aq) + H2O −0.276
Ni2+
+ 2 e− ⇄ Ni(s) −0.25
MoO2(s) + 4 H+ + 4 e−
⇄ Mo(s) + 2 H2O −0.15
Si(s) + 4 H+ + 4 e−
⇄ SiH4(g) −0.14
Sn2+
+ 2 e− ⇄ Sn(s) −0.13
Pb2+
+ 2 e− ⇄ Pb(s) −0.13
CO2(g) + 2 H+ + 2 e−
⇄ CO(g) + H2O −0.11
HCOOH(aq) + 2 H+ + 2 e−
⇄ HCHO(aq) + H2O −0.03
2 H+ + 2 e− ⇄ H2(g) 0.0000
S4O62−
+ 2 e− ⇄ 2 S2O3
2− +0.08
HgO(s) + H2O + 2 e− ⇄ Hg(l) + 2 OH
− +0.0977
C(s) + 4 H+ + 4 e−
⇄ CH4(g) +0.13
Sn4+
+ 2 e− ⇄ Sn
2+ +0.15
Cu2+
+ e− ⇄ Cu
+ +0.159
HSO4− + 3 H+
+ 2 e− ⇄ SO2(aq) + 2 H2O +0.16
SO42−
+ 4 H+ + 2 e−
⇄ SO2(aq) + 2 H2O +0.17
TiO2+
+ 2 H+ + e
− ⇄ Ti
3+ + H2O +0.19
H3AsO3(aq) + 3 H+ + 3 e−
⇄ As(s) + 3 H2O +0.24
UO2+ + 4 H+
+ e− ⇄ U
4+ + 2 H2O +0.273
Bi3+
+ 3 e− ⇄ Bi(s) +0.32
VO2+
+ 2 H+ + e
− ⇄ V
3+ + H2O +0.34
AP Chemistry—WPHS AP Chem Page 8 3/24/2011
Cu2+
+ 2 e− ⇄ Cu(s) +0.340
O2(g) + 2 H2O + 4 e− ⇄ 4 OH
−(aq) +0.40
CH3OH(aq) + 2 H+ + 2 e−
⇄ CH4(g) + H2O +0.50
Cu+ + e
− ⇄ Cu(s) +0.520
CO(g) + 2 H+ + 2 e−
⇄ C(s) + H2O +0.52
I2(s) + 2 e− ⇄ 2 I−
+0.54
H3AsO4(aq) + 2 H+ + 2 e−
⇄ H3AsO3(aq) + H2O +0.56
MnO4− + 2 H2O + 3 e−
⇄ MnO2(s) + 4 OH− +0.59
O2(g) + 2 H+ + 2 e−
⇄ H2O2(aq) +0.70
PtCl42−
+ 2 e− ⇄ Pt(s) + 4 Cl
− +0.758
Fe3+
+ e− ⇄ Fe
2+ +0.77
Ag+ + e
− ⇄ Ag(s) +0.7996
Hg22+
+ 2 e− ⇄ 2 Hg(l) +0.80
Hg2+
+ 2 e− ⇄ Hg(l) +0.85
MnO4− + H
+ + e
− ⇄ HMnO4
− +0.90
2 Hg2+
+ 2 e− ⇄ Hg2
2+ +0.91
Pd2+
+ 2 e− ⇄ Pd(s) +0.915
[AuCl4]− + 3 e−
⇄ Au(s) + 4 Cl− +0.93
MnO2(s) + 4 H+ + e
− ⇄ Mn
3+ + 2 H2O +0.95
[AuBr2]− + e
− ⇄ Au(s) + 2 Br
− +0.96
Br2(l) + 2 e− ⇄ 2 Br
− +1.066
Br2(aq) + 2 e− ⇄ 2 Br
− +1.0873
IO3− + 5 H+
+ 4 e− ⇄ HIO(aq) + 2 H2O +1.13
HSeO4− + 3 H+
+ 2 e− ⇄ H2SeO3(aq) + H2O +1.15
Ag2O(s) + 2 H+ + 2 e−
⇄ 2 Ag(s) + H2O +1.17
ClO3− + 2 H+
+ e− ⇄ ClO2(g) + H2O +1.18
Pt2+
+ 2 e− ⇄ Pt(s) +1.188
ClO2(g) + H+ + e
− ⇄ HClO2(aq) +1.19
2 IO3− + 12 H+
+ 10 e− ⇄ I2(s) + 6 H2O +1.20
ClO4− + 2 H+
+ 2 e− ⇄ ClO3
− + H2O +1.20
O2(g) + 4 H+ + 4 e−
⇄ 2 H2O +1.23
MnO2(s) + 4 H+ + 2 e−
⇄ Mn2+
+ 2H2O +1.23
Cl2(g) + 2 e− ⇄ 2 Cl
− +1.36
Cr2O7− − + 14 H+
+ 6 e− ⇄ 2 Cr
3+ + 7 H2O +1.33
CoO2(s) + 4 H+ + e
− ⇄ Co
3+ + 2 H2O +1.42
2 NH3OH+ + H
+ + 2 e−
⇄ N2H5+ + 2 H2O +1.42
2 HIO(aq) + 2 H+ + 2 e−
⇄ I2(s) + 2 H2O +1.44
Ce4+
+ e− ⇄ Ce
3+ +1.44
BrO3− + 5 H+
+ 4 e− ⇄ HBrO(aq) + 2 H2O +1.45
β-PbO2(s) + 4 H+ + 2 e−
⇄ Pb2+
+ 2 H2O +1.460
α-PbO2(s) + 4 H+ + 2 e−
⇄ Pb2+
+ 2 H2O +1.468
2 BrO3− + 12 H+
+ 10 e− ⇄ Br2(l) + 6 H2O +1.48
2ClO3− + 12 H+
+ 10 e− ⇄ Cl2(g) + 6 H2O +1.49
MnO4− + 8 H+
+ 5 e− ⇄ Mn
2+ + 4 H2O +1.51
HO2• + H
+ + e
− ⇄ H2O2(aq) +1.51
Au3+
+ 3 e− ⇄ Au(s) +1.52
NiO2(s) + 4 H+ + 2 e−
⇄ Ni2+
+ 2 OH− +1.59
2 HClO(aq) + 2 H+ + 2 e−
⇄ Cl2(g) + 2 H2O +1.63
Ag2O3(s) + 6 H+ + 4 e−
⇄ 2 Ag+ + 3 H2O +1.67
HClO2(aq) + 2 H+ + 2 e−
⇄ HClO(aq) + H2O +1.67
Pb4+
+ 2 e− ⇄ Pb
2+ +1.69
MnO4− + 4 H+
+ 3 e− ⇄ MnO2(s) + 2 H2O +1.70
H2O2(aq) + 2 H+ + 2 e−
⇄ 2 H2O +1.78
AgO(s) + 2 H+ + e
− ⇄ Ag
+ + H2O +1.77
Co3+
+ e− ⇄ Co
2+ +1.82
Au+ + e
− ⇄ Au(s) +1.83
BrO4− + 2 H+
+ 2 e− ⇄ BrO3
− + H2O +1.85
Ag2+
+ e− ⇄ Ag
+ +1.98
S2O82−
+ 2 e− ⇄ 2 SO4
2− +2.010
O3(g) + 2 H+ + 2 e−
⇄ O2(g) + H2O +2.075
HMnO4− + 3 H+
+ 2 e− ⇄ MnO2(s) + 2 H2O +2.09
F2(g) + 2 e− ⇄ 2 F−
+2.87
F2(g) + 2 H+ + 2 e−
⇄ 2 HF(aq) +3.05
AP Chemistry—WPHS AP Chem Page 9 3/24/2011
Calculating & Using Electrical Potential
The table above assumes that you have a __________ M solution at ________atm and _________ºC
Example 1: What would be the electrical potential for the reaction:
PbO2 + Na Pb2+
+ Na+
Fe3+
+ Mg Mg2+
+ Fe2+
Example 2:
Is H2(g) capable of reducing Ag+(aq)
Is H2(g) capable of reducing Ni2+
(aq)
Is Fe2+
(aq) capable of reducing VO2+
Is Fe2+
capable fo reducing Cr3+
(aq)
Example 3: Rank the following from strongest oxidizing agent to weakest oxidizing agent:
Ce4+
Ce3+
Fe2+
Fe3+
Mg2+
Mg Ni2+
Sn
AP Chemistry—WPHS AP Chem Page 10 3/24/2011
17.3: Cell Potential and Equilibrium
∆G=-nFEº
Example: Using the data in table 17.1, calculate ∆Gº for the reaction:
Cu2+
(aq) + Fe(s) Cu(s) + Fe2+
(aq)
17.4: The Nernst Equation
What happens when concentration and temperatures are not standard?
Nernst Equation
QnF
RTEE ln
Sometimes written as:
Qn
EE ln0592.0
Assuming 25ºC
Example 1: What is the electrical potential for the following cell with the following concentrations?
VO2+ + Zn Zn
2+ + VO
2+
[VO2+] = 2.0 M [H+] = 0.50 M
[VO2+
] = 1.0 x 10-2
M [Zn2+
] = 0.10 M
First: Write the balanced equation: Use the table of reduction potentials
Second: find Eº
Third: Use the Nernst Equation and plug in the concentration values for Q
AP Chemistry—WPHS AP Chem Page 11 3/24/2011
Concentration Cells:
17.4-17.5: Batteries and Corrosion
A Galvanic Cell or a series of galvanic cells hooked together.
AP Chemistry—WPHS AP Chem Page 12 3/24/2011
Corrosion
AP Chemistry—WPHS AP Chem Page 13 3/24/2011
17.7: Electrolysis
The opposite of a galvanic cell: Pump electricity through a non ___________ reaction.
Comparison of a galvanic cell and an electrolytic cell
Electrolytic Cell ____________________________
Electrolysis __________________________________
Ampere: ___________________________
Faraday ________________________________
The Story of Aluminum
AP Chemistry—WPHS AP Chem Page 14 3/24/2011
Example 1:
Calculate the amount of time required to produce 1000 g of magnesium metal by electrolysis of molten
MgCl2 using a current of 50A.
Example 2:
A Cr3+
(aq) solution is electrolyzed, using a current of 7.60 A. What mass of Cr (s) is plated out after
2.00 days?
What amperage is required to plate out 0.250 mol Cr form a Cr3+
solution in a period of 8.00 hours?
AP Chemistry—WPHS AP Chem Page 15 3/24/2011
Example 3:
What reaction will take place at the cathode and the anode when each of the following is electrolyzed?
a. 1.0 M KF solution
b. 1.0 M CuCl2 solution
c. 1.0 M H2O2 solution containing 1.0 M HCl
10, 122, 299 ---> 162, 5, 122, 60, 60, 188
AP Chemistry—WPHS AP Chem Page 16 3/24/2011
AP Style Questions
2002
AP Chemistry—WPHS AP Chem Page 17 3/24/2011
2000