ใบความรู้ที่ 6 ...
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Transcript of ใบความรู้ที่ 6 ...
5
6 1.
2
1. (Primary cell)
2. (Secondary cell Reversible cell)
- 1 ()() 1
-Zn
Fe
Cd
Cd
Pd
Zn (Hg)
Zn (Hg)
LiMnO2NiO2NiO2Ag2O AgO
PbO2HgO
MnO2MnO2NH4Cl - ZnCl2KOH
KOH
KOH
H2SO4KOH-ZnO
KOH
KOH0.9 - 1.4
1.2 - 1.4
1.1 - 1.3
1.0 - 1.1
1.95 - 2.04
1.30
0.9 - 1.2
3.4
1.1 (Dry cell)
2
1. (Acidic dry cells)
2. (Alkaline dry cells)
. flash ( Leclanche cell) Georges Leclanche .. 1866
1.5 0.8 1.3
1
1 2 () (NH4Cl) (IV) (IV) +4 MnO2 +3 Mn2O3
() Zn ; Zn (s) ( Zn2+ (aq) + 2e-
E0 = +0.763 V
() ;
MnO2 (s) + 2NH4+ (aq) + 2e- ( Mn2O3 (s) + 2NH3 (g) + H2O (l) E0 = +0.50 V
;
Zn(s) + MnO2 (s) + 2NH4+ (aq)(Zn2+ (aq) + Mn2O3 (s) + 2NH3 (g) + H2O (l) ;
= 1.26 V
(250 C 1 atm) 1.5
[ Zn(NH3)4]2+
Zn2+ (aq) + 4NH3 (g) ( [ Zn(NH3)4]2+(aq)
Polarization
(0.0666 kwh/kg)
. (Alkaline dry cells) OH- (Paste) (IV) 1.54
; Zn(s) + 2OH- (aq) ( ZnO (s) + H2O (l) + 2e-
; 2MnO2 (s) + H2O (l) + 2e- ( Mn2O3 (s) + 2OH- (aq)
Zn(s) + 2MnO2 (s) ( Zn(OH)2 (s) + Mn2O3 (s)
2
. ( Mercury cell) - (Rubin - mallory cell) MnO2 HgO ( (II) ) 1.35
; Zn (s) + 2OH- (aq) ( ZnO (s) + H2O (l) + 2e- , E0 = 1.25 V
; HgO (s) + H2O (l) + 2e- ( Hg (l) + 2OH- (aq), E0 = 0.098 V
; Zn (s) + HgO (s) ( ZnO (s) + Hg (l) ,
= 1.35 V
3
. (Zinc-silver oxide cell Button Battery) AgO MnO2 1.58 V
; Zn (s) + 2OH- (aq) ( ZnO (s) + H2O (l) + 2e- , E0 = 1.25 V
; 2AgO (s) + H2O (l) + 2e- ( Ag2O (s) + 2OH- (aq) , E0 = 0.61 V
; Zn (s) + 2AgO (s) ( ZnO (s) + Ag2O (s) ,
= 1.86 V
(II) (I) (Ag2O) (Ag)
Zn (s) + Ag2O (s) + H2O (l) ( Zn(OH)2 (s) + 2Ag (s) , E0 = 1.58 V
4 1.2. (Secondary cell Reversible cell)
(Charging Recharging) -
. (Lead storage battery) (0.022 Kwh/kg) 6 12 (IV) (PbO2) 40% ( 5.3 mol/dm3 ) 1.3 1.1
5
; Pb (s) + SO42- (aq) ( PbSO4 (s) + 2e- , E0 = +0.356 V
; PbO2 (s) + 4H+ (aq) + SO42- (aq) + 2e- ( PbSO4 (s) + 2H2O (l) , E0 = +1.685 V
Pb (s) + PbO2 (s) + 4H+ (aq) + 2SO42- (aq) ( 2PbSO4 (s) + 2H2O (l) ,
= +2.041 V
PbSO4 () Pb 2 (H2SO4) 5.3 mol / dm3 1.
6
(Pb)
A (Anode) (IV) (PbO2) Pb Pb PbO2 ()
(1) Pb (s) ( Pb2+ (aq) + 2e-
(2) Pb2+ (aq) + 2H2O (l) ( PbO2 (s) + 4H+ (aq) + 2e-
; Pb(s) + 2H2O (l) ( PbO2 (s) + 4H+ (aq) + 4e- ()
B (Cathode) H2 Pb H+ H2
2H+ (aq) + 2e- ( H2 (g)
2.
7
17.7 B A
B Pb Pb2+ SO42- PbSO4 B Anode
(1) Pb(s) ( Pb2+ (aq) + 2e-
(2) Pb2+ (aq) + SO42+ (aq) ( PbSO4 (s)
; Pb (s) + SO42- (aq) ( PbSO4 (s) + 2e-
.. (3)
B PbO2 Pb PbO2 H+ Pb2+ H2O Pb2+ SO42- PbSO4 A Cathode
(4) PbO2 (s) + 4H+ (aq) + 2e- ( Pb2+ (aq) + 2H2O (l)
(5) Pb2+ (aq) + SO42- (aq) ( PbSO4 (s)
; PbO2 (s) + 4H+ (aq) + SO42- (aq) + 2e- ( PbSO4 (s) + 2H2O (l) (6)
(3) + (6)
Pb (s) + PbO2 (s) + 4H+ (aq) + 2 SO42- (aq) ( 2PbSO4 (s) + 2H2O (l)
3. 2
2
2
A Anode
PbSO4 (s) + 2H2O (l) ( PbO2 (s) + 4H+ (aq) + 2e-
B Cathode
PbSO4 (s) + 2e- ( Pb (s) + SO42- (aq)
2
2PbSO4 (s) + 2H2O (l) ( Pb(s) + PbO2 (s)+4H+ (aq) + 2SO42- (aq)
Pb(s) + PbO2 (s)+4H+ (aq) + 2SO42- (aq) 2PbSO4 (s) + 2H2O (l)
2
Pb- - - - - -
PbO2- - - - - -
1.
2.
3. 2 , 3 ,
4.
5.
= +2.041 V 6 12 V
6.
Pb , PbO2 , H2SO4PbSO4 , H2O
PbSO4 , H2OPb , PbO2 , H2SO4
7. H2SO4 40% 1.3 H2SO4 1.10
8. H2SO4
. - (Nickel - Cadmium cell) (Nicad cell)
8 -
- (IV)
; Cd (s) + 2OH- (aq) ( Cd (OH)2 (s) + 2e-
, E0 = 0.81 V
; NiO2 (s) + 2H2O (l) + 2e- ( Ni(OH)2 (s) + 2OH- (aq), E0 = 0.49 V
; Cd (s) + NiO2 (s) + 2H2O (l) ( Cd (OH)2 (s) + Ni(OH)2 (s) ,
= +1.30 V
Polarization 1.30 V 3 - -
2.041 V1.30 V
()
()Pb
PbO2Cd
NiO2
H2SO4 KOH NaOH
(((((((((((((((((((((((((
_992120431.unknown
_992122490.unknown
_992126379.unknown
_992127418.unknown
_992120914.unknown
_992120006.unknown