Transcript Chapter 20 Electrochemistry Chemistry, The Central Science

Chemistry, The Central Science, 11th edition
Theodore L. Brown; H. Eugene LeMay, Jr.;
Bruce E. Bursten and Catherine J. Murphy
Chapter 20
Electrochemistry
Donna Narsavage Heald
Siena College
Loudonville, NY
 2009, Prentice Hall
For the reaction given below, what substance is
oxidized and what is reduced?
3 NO2– +
1.
2.
3.
4.
5.
Cr2O72 – +
8 H+
2 Cr3+ + 3 NO3– + 4 H2O
N of NO2– is reduced; Cr of Cr2O72– is oxidized.
N of NO2– is oxidized; Cr of Cr2O72– is reduced.
O of NO2– is oxidized; Cr of Cr2O72– is reduced.
Cr3+ is reduced; N of NO2– is oxidized.
N of NO3– is oxidized; Cr3+ is reduced.
For the reaction given below, what substance is
oxidized and what is reduced?
3 NO2– +
1.
2.
3.
4.
5.
Cr2O72 – +
8 H+
2 Cr3+ + 3 NO3– + 4 H2O
N of NO2– is reduced; Cr of Cr2O72– is oxidized.
N of NO2– is oxidized; Cr of Cr2O72– is reduced.
O of NO2– is oxidized; Cr of Cr2O72– is reduced.
Cr3+ is reduced; N of NO2– is oxidized.
N of NO3– is oxidized; Cr3+ is reduced.
When the following reaction is balanced, what
are the coefficients for each substance?
__Ag + __O2
1.
2.
3.
4.
5.
1, 1, 2, 1, 1
1, 1, 4, 1, 2
1, 1, 2, 1, 2
4, 1, 2, 1, 2
4, 1, 4, 4, 2
+ __H+
__Ag+
+
__H2O
When the following reaction is balanced, what
are the coefficients for each substance?
__Ag + __O2
1.
2.
3.
4.
5.
1, 1, 2, 1, 1
1, 1, 4, 1, 2
1, 1, 2, 1, 2
4, 1, 2, 1, 2
4, 1, 4, 4, 2
+ __H+
__Ag+
+
__H2O
Given the following reaction, which is true?
Cu(s) + 2 Ag+(aq)
1.
2.
3.
4.
5.
Cu2+(aq) + 2 Ag(s)
E° = +0.46 V
Plating Ag onto Cu is a spontaneous process.
Plating Cu onto Ag is a spontaneous process.
Plating Ag onto Cu is a nonspontaneous process.
Plating Cu onto Ag is a nonspontaneous process.
Energy will have to be put in for the reaction to proceed.
Given the following reaction, which is true?
Cu(s) + 2 Ag+(aq)
1.
2.
3.
4.
5.
Cu2+(aq) + 2 Ag(s)
E° = +0.46 V
Plating Ag onto Cu is a spontaneous process.
Plating Cu onto Ag is a spontaneous process.
Plating Ag onto Cu is a nonspontaneous process.
Plating Cu onto Ag is a nonspontaneous process.
Energy will have to be put in for the reaction to proceed.
Given the following reaction, which is true?
Cu(s) + 2 Ag+(aq)
Cu2+(aq) + 2 Ag(s)
E° = +0.46 V
Given the following reaction, which is true?
Cu(s) + 2 Ag+(aq)
Cu2+(aq) + 2 Ag(s)
E° = +0.46 V
Which substance is the stronger oxidizing
agent?
1.
2.
3.
4.
5.
Br2
O2
NO3–
H+
Cl2
Which substance is the stronger oxidizing
agent?
1.
2.
3.
4.
5.
Br2
O2
NO3–
H+
Cl2
Which substance is the stronger reducing
agent?
1.
2.
3.
4.
5.
H 2 O2
Mn2+
NO
I–
Ag
Which substance is the stronger reducing
agent?
1.
2.
3.
4.
5.
H 2 O2
Mn2+
NO
I–
Ag