chuong 2 dien cuc6346
Post on 16-Sep-2015
41 Views
Preview:
DESCRIPTION
TRANSCRIPT
-
05/03/2015
1
GV: TS MAI TH HI H
Chng 2
CN BNG TRN B MT IN CC
S tch in giao din 2 pha
Trong lng dung dch (1 pha bt k) :
Mi ht (ion/phn t dung mi) chu cc lc tc dng t mi hng nh nhau
Trong 1 th tch dd ln :
Tng vect mmen lng cc ca cc ht = 0 : cc ht khng s u tin sp
xp theo 1 hng no.
Tng in tch ca cc ht = 0.
5-Mar-15 TS. MTHH 2
S nh hng hn lon ca lng cc nc
-
05/03/2015
2
S tch in giao din 2 pha
5-Mar-15 TS. MTHH 3
Ti giao din dung dch/pha P (kh, kim loi, thnh bnh cha) :
Lc tc dng ln ht t pha pha P t pha lng dd
Cc ht gn giao din phn b khc trong lng dd : phn t dung mi u tin
quay theo 1 hng, c s tng/gim s ion dng so vi ion m
Phn dd gn giao din tr nn tch in (c d in tch qs)
in trng ca pha dd tc ng ln ht trong pha P :
Nu P = kim loi : electron trn KL c th chuyn v pha/ra xa giao din
B mt pha P tch in
Hiu in th gia 2 pha = bc nhy th
Cu trc ca giao din tch in - Mu Helmholtz-Perrin in tch d trn kim loi thu ht cc ion tri du trong dd li gn b mt :
2 lp in tch d tri du , cng ln nm song song lp in kp
lp in kp t in vi in dung C :
Tm ca cc ion pha dd to thnh mt phng Helmholtz ngoi (outer Helmholtz
plane - OHP)
S gim th gia 2 lp l tuyn tnh
5-Mar-15 TS. MTHH 4
d
-
05/03/2015
3
Cu trc ca giao din tch in - Mu Gouy-Chapman
Mt s ion (solvat ha) ri OHP, phn tn xa hn vo lng dd do chuyn ng
nhit. Cng ra xa giao din, mt in tch d cng gim n 0.
Phn in tch d ca dd = Lp khuch tn qd .
Lp khuch tn qd bn in tch qd t cch b mt KL khong cch -1
5-Mar-15 TS. MTHH 5
Cu trc ca giao din tch in - Mu Stern
in tch d qs trong dd chia lm 2 phn :
Phn khng di ng st b mt KL trong OHP : qH
Phn phn tn trong dung dch : qG
2 s gim th :
5-Mar-15 TS. MTHH 6
-
05/03/2015
4
Mt s kiu bc nhy th
Kim loi 1/Kim loi 2 : th tip xc loi 1
Kim loi/Kh : th tip xc loi 2
Dung dch/Kh : th tip xc loi 3
Kim loi/Dung dch in ly : th in cc
Dung dch 1/Dung dch 2 : th khuch tn hay th mng
Ngun gc :
S trao i cc ht in tch gia 2 pha
S hp ph chn lc ion/phn t c cc ranh gii phn chia 2 pha
5-Mar-15 TS. MTHH 7
Khng th o c bc nhy th gia 2 pha bn cht khc nhau
Th in cc - Mt s loi in cc
Cc s pht sinh bc nhy th c ch xy ra trn giao din :
kim loi cht dn in ion in cc
Th in cc = Bc nhy th c c do s chuyn ion, electron thng qua
cc p trn in cc.
Cc loi in cc :
5-Mar-15 TS. MTHH 8
1. in cc loi 1 : lm vic thun nghch vi cation/anion
M(r)|M+
(dd) : M+
(dd) + e M(r)
Ag(r)|AgNO3 (dd)
Pt | H2 (k)|H+ (dd) : 2H
+ + 2e- H2
Pt | Cl2 (k)|Cl- (dd)
-
05/03/2015
5
Mt s loi in cc
5-Mar-15 TS. MTHH 9
2. in cc loi 2 : KL|mui kh tan | dd cha anion ca mui kh tan
M(r) | MX(r) | X-(dd) : MX(r) + e M(r) + X
-(dd)
c Calomen : Hg(l) | Hg2Cl2(r) | KCl(dd) :
Hg2Cl2 (r) + 2e- 2Hg (l) + 2Cl-
c bc clorua : Ag(r) | AgCl(r) | KCl(dd)
c sulfat thy ngn : Hg(l) | HgSO4(r) | H2SO4(dd)
3. in cc loi 3 :
KL|2 loi mui kh tan cng anion | dd cha cation ca mui d tan hn
Pb(r) | PbCO3(r), CaCO3(r) | Ca2+
(dd)
Ag(r) | AgCl(r), PbCl2(r) | Pb2+
(dd) : 2AgCl(r) + 2e + Pb2+ 2Ag(r) + PbCl2(r)
5. c kh : Pt(r)|X2(k)|X+
(dd) : X+ + e X2
c hydro : Pt | H2 (k)|H+ (dd)
c clo : Pt | Cl2 (k)|Cl- (dd)
c oxy : Pt | O2 (k)|H+ (dd) hay Pt | O2 (k)|OH
- (dd) :
O2 + 4H+ + 4e 2H2O
O2 + 2H2O + 4e 4OH-
5-Mar-15 TS. MTHH 10
4. c oxi ha kh : kim loi qu | dd c dng oxi ha v kh
Pt(r)|M+
(dd), M2+
(dd) : M2+
(dd) + e- M+(dd)
Pt(r)|Fe3+
(dd), Fe2+
(dd)
Pt(r)|MnO4-, Mn2+, H+
in cc tiu chun : kh c p sut 1 atm, hot cht trong dung dch = 1
Mt s loi in cc
-
05/03/2015
6
in cc qui chiu (Reference electrode)
5-Mar-15 TS. MTHH 11
c Hydro tiu chun (SHE)
(Standard Hydrogen Electrode)
Pt(r)|H2(k) (1atm) |H+
(dd) (1M)
Qui c : in th = 0 mi nhit
c Calomel bo ha (SCE)
(Saturated Calomel Electrode)
c qui chiu (hay c so snh) : c th c n nh, d lp li; dng lm mc
xc nh cc th in cc khc.
Pin Galvani K hiu pin
c ZnZn2+
5-Mar-15 TS. MTHH 12
c CuCu2+ c Graphite | I-(dd) | I2(r)
c Graphite | MnO4-
(dd), H+
(dd), Mn2+
(dd)
Zn(r)Zn2+(dd)Cu2+(dd) Cu(r) anode (-) cathode (+)
: Ranh gii pha
: giao din khng c th tip xc lng (nh khi dng cu mui)
: giao din c th tip xc lng
-
05/03/2015
7
1 2
3 3
L1 L2
ion
B
Sc in ng ca pin Galvani
Khi mch h (dng in = 0, cc giao din trng thi cn bng) :
5-Mar-15 TS. MTHH 13
Tng cc bc nhy th theo 1 vng kn = 0
E + B3 + 32 + 2L2+L2L1 + L11+ 13 + 3B = 0
Vi : B3 + 3B = 0
32 + 13 = 3 - 2 + 1 - 3 = 12
Sc in ng ca pin E c c do cc bc
nhy th :
- Ranh gii gia B v kim loi 3 : B3
- Ranh gii gia kim loi 3 v 2 : 32
- Ranh gii gia kim loi 2 v L2 : 2L2
- Ranh gii gia dung dch L2 v L1 : L2L1
E = 1L1 - 2L2 - 12+ L1L2
Nu b qua th tip xc :
E = 1L1 - 2L2 = hiu 2 th in cc
Zn(r) + 2H+
(dd) Zn2+
(dd) + H2(k)
+1 0 0 +2
P oxi ha kh
Zn 2e Zn2+ : Qt oxi ha Zn
Zn b oxi ha : soh tng 0 +2
Zn l cht kh : cho/mt e
Zn c tnh kh : Zn kh H+
Qu trnh/S oxi ha A (bi B)
A b oxi ha : soh A tng
A l cht kh : cho/mt e
A c tnh kh : A kh B
2H+ + 2e H2 : Qt kh H+
H+ b kh : soh gim +10
H+ l cht oxi ha : nhn e
H+ c tnh oxi ha : H+ oxi ha Zn
Qu trnh/S kh B (bi A)
B b kh : soh B gim
B l cht oxi ha : nhn e
B c tnh oxi ha : oxi ha A
2 cp Ox/Kh
Zn2+/Zn
H+/H2
Bt kh H2 bm trn l Zn
Zn 2e Zn2+
2H+ + 2e H2
Cht kh Cht oxi ha
Cht kh Cht oxi ha
5-Mar-15 TS. MTHH 14
-
05/03/2015
8
1. Cu + 2Fe3+ Cu2+ + 2Fe2+
Sa li cc pht biu sai :
A. Cu l dng kh, Cu2+ l dng oxi ha.
B. Ion Fe+3 l cht kh, Fe2+ l cht oxi ha.
C. Cp Ox/kh l Cu2+/Cu v Fe2+/Fe3+
D. Cu c tnh kh v oxi ha c Fe3+
E. Fe3+ oxi ha Cu thnh Cu2+
F. Qu trnh oxi ha Cu2+ (cht oxi ha)
G. Qu trnh kh Fe2+ (cht kh)
5-Mar-15 TS. MTHH 15
Phn ng in cc
Qt oxi ha () Anode
Qt kh (+) Cathode
electron
Cu mui : trung ha in tch 2 bnh cha in cc
Zn2+ i vo dd Cu2+ t dd bm vo thanh Cu
Zn b mn
Cu sinh thm
* Dng in : Cu Zn
* 2 in cc b bin i
Thc nghim :
5-Mar-15 TS. MTHH 16
-
05/03/2015
9
5-Mar-15 TS. MTHH 17
2. Pin Zn(r)Zn2+(dd)Ag+(dd) Ag(r)
Chn pht biu ng :
A. Dng in chy t c Zn sang c Ag
B. Dng electron chy t c Zn sang c Ag
C. Khi pin lm vic, Zn b ha tan dn
D. Khi pin lm vic, khi lng thanh Ag tng ln n mt gi tr khng i
E. P trn anode l Zn2+ + 2e Zn
F. P trn cathode l Ag - e Ag+
G. Zn kh c ion bc
Cu trc chung ca pin Galvani
5-Mar-15 TS. MTHH 18
Gm 2 in cc & 2 cp oxi ha kh :
(-) Anode : (Ox1/Kh1) Qt oxi ha :
(+) Cathode : (Ox2/Kh2) Qt kh :
Khi mch h (open circuit) : Sc in ng Epin = th mch h
Khi pin hot ng (phng in) : Epin gim dn
Epin = 0 : khng cn dng e chuyn ng, p trn 2 in cc trng thi cn bng.
Voltaic Cell/ Galvanic Cell Voltage (V)
Pin alkaline (n pin) 1.5
Pin ch-axit ( t) (6 pin 12 V) 2.1
Pin my tnh tay (thy ngn) 1.3
Pin Lithium-ion laptop 3.7
P xy ra trong pin l
t pht c G < 0
Kh1 ne Ox1
Ox2 + ne Kh2
-
05/03/2015
10
Cch xc nh cc th in cc theo thang SHE
5-Mar-15 TS. MTHH 19
Cc th in cc c xc nh tng i so vi th c Hydro theo nguyn tc :
Thit lp pin gm :
c Hydro tiu chun H+/H2
c cn xc nh th cn tm
c gi tr Epin cn tm
3. H pin nh hnh v c dng in chy t c Hydro c Zn v Epin = 0,76 V
Tm th in cc km.
4. Pin Pt|H2 (1atm) |H+ (1M) Ag+ (1M)|Ag c sc
in ng 0,8V. Tm th c ca bc.
Th in cc kh Th in cc oxi ha
5-Mar-15 TS. MTHH 20
Qui c : Th c vit ng vi qt kh = Th c kh Ox/Kh
Vd : oZn/Zn2+ = 0,76 V o
Zn2+/Zn = 0,76 V
Kh ne Ox Kh/Ox Th c oxi ha
Ox + ne Kh Ox/Kh Th c kh
Epin = Ox/Kh (+) + Kh /Ox (-)
Epin = Ox/Kh (+) Ox/Kh (-)
Kh/Ox = Ox/Kh
Epin = cathode (+) anode (-)
-
05/03/2015
11
+2.87
+1.36
+1.23
+0.80
+0.77
+0.40
+0.34
0.00
0.44
0.83
2.71
Tnh
kh
tng d
n (d
n
h
n
g ele
ctron
)
Tn
h o
xi h
a
tn
g d
n (
d
nh
n e
lect
ron
) F2(g) + 2e
2F(aq)
Cl2(g) + 2e 2Cl(aq)
MnO2(g) + 4H+(aq) + 2e Mn2+(aq) + 2H2O(l)
Ag+(aq) + e Ag(s)
Fe3+(g) + e Fe2+(aq)
O2(g) + 2H2O(l) + 4e 4OH(aq)
Cu2+(aq) + 2e Cu(s)
Fe2+(aq) + 2e Fe(s)
2H2O(l) + 2e H2(g) + 2OH
(aq)
Na+(aq) + e Na(s)
2H+(aq) + 2e H2(g)
Bng th c kh tiu chun ca cp Ox/Kh (298K)
0.74 Cr3+(aq) + 3e Cr(s)
+0.53 I2(s) + 2e 2I- (aq)
0.76 Zn2+(aq) + 2e Zn(s)
+1.08 Br2(l) + 2e 2Br- (dd)
+1.51 MnO4-(aq) + 8H+(aq) + 5e Mn2+(aq) + 4H2O(l)
5-Mar-15 TS. MTHH 21
+0.52 Cu+(aq) + 2e Cu(s)
+0.16 Cu2+(aq) + 2e Cu+(aq)
+0.22 AgCl(s) + e Ag(s) + Cl-
5. Cr(r)Cr3+(dd)Ag+(dd)Ag(r). Pht biu sau ng hay sai :
A. P cathode : Cr3+ + 3e- Cr ; p anode Ag Ag+ + e-
B. P cathode : Ag+ + e- Ag ; p anode Cr Cr3+ + 3e-
C. Eopin = o
Ag+/Ag o
Cr3+/Cr = 0,06V
D. Sut in ng chun 1,54V
6. Graphite | I-(dd) | I2(r)MnO4- (dd), H+ (dd), Mn2+ (dd) | Graphite.
Chn pht biu sai :
A. Ti cathode xy ra s kh : MnO4- + 8H+ + 5e- Mn2+ + 4H2O
B. Eopin = o
MnO4-/Mn2+ o
I2/I- = 0,98V
C. Ti anode xy ra s oxi ha : I2 + 2e- 2I-
D. P trong pin : 2MnO4- + 16H+ + 10I- 2Mn2+ + 5I2 + 8H2O
7. Pin in vi p tng cng sau c E
pin = 1,83V : Br2(dd) + Zn(r) Zn2+
(dd) + 2Br-(dd)
Zn2+/Zn = -0,76V. Gi tr
Br2/Br- l :
A. 2,59V B. 1,07V C. -1,07V D. -2,59V
a.
5-Mar-15 TS. MTHH 22
-
05/03/2015
12
Cp c th c ln
hn l cc dng
Tng quan ln - kh nng oxi ha/ kh
5-Mar-15 TS. MTHH 23
Ox2/Kh2 > Ox1/Kh1 :
Cathode (+) : Ox2/Kh2 Ox2 + ne Kh2
Anode (-) : Ox1/Kh1 Kh1 ne Ox1
Ox1 + ne Kh1
Ox2 d nhn e hn Ox1 Kh2 kh nhng e hn Kh1
Kh2 ne Kh1
cng dng dng oxi ha cng mnh, cng d nhn electron
cng m dng kh cng mnh, cng d nhng electron
Ox2 > Ox1 Tnh oxi ha : Tnh kh : Kh2 < Kh1
8. Cho
Fe2+/Fe = - 0,44 V v
H+/H2 . Chn ng :
A. Pin Pt|H2 (1atm) |H+ (1M) Fe2+ (1M)|Fe
B. Pin Fe|Fe2+ (0,1M) H+ (1M) | H2 (0,1atm) | Pt
C. P Fe + H+ Fe2+ + H2
D. H+ c tnh oxi ha yu hn Fe2+
5-Mar-15 TS. MTHH 24
-
05/03/2015
13
Nng lng t do ca p trong pin sc in ng
a (tc) b (sp)
G = cng in c ch cc i m pin thc hin c
G = -nFEpin (vit cho bn p c : G = -nF)
Go = -nFEopin (vit cho bn p c : Go = -nFo)
n : s e- cn bng ng vi p c vit
F = 96500 C/mol
E : sc in ng (Volt = Joule/Coulomb)
P trong pin in ha c :
G < 0, Epin > 0 : p t xy ra, pin = pin Galvani
G > 0, Epin < 0 : p khng t xy ra, pin = bnh in phn
G = 0, Epin = 0 : p trn cc in cc ang trng thi cn bng.
5-Mar-15 TS. MTHH 25
9. Tm th c chun ca Cu2+/Cu+ bit th in cc chun ca 2 cp Cu2+/Cu
v Cu+/Cu ln lt l 0,34 V v 0,522 V. (S : 0,158V)
Quy tc Luther :
no = niio
o : th tiu chun ca p tng cng
n : s electron tham gia vo p tng cng
io : th tiu chun ca p trung gian
ni : s electron tham gia vo p trung gian
5-Mar-15 TS. MTHH 26
-
05/03/2015
14
Phng trnh Nernst tnh th in cc
5-Mar-15 TS. MTHH 27
P trong pin : a (tc) b (sp)
n = s e trao i cn bng
Epin = Eo
pin RT
nF lnQ
Epin = Eo
pin 0,059
n logQ
aspb
atca
Thng s p : Q =
298K :
G = Go + RTlnQ
Chia 2 v cho nF :
298K :
Ox/Kh = o
Ox/Kh 0,059
n logQ
P in cc : aOx + ne bKh
Th in cc & s ph thuc nng cc cht v thay i theo thi gian.
10. Vit phng trnh Nernst :
a. Cu2+ (dd) + 2e Cu (r)
b. Pt|Fe3+ (dd), Fe2+ (dd)
c. Pt|Cl2 (k) | Cl- (dd)
d. MnO4- + 8H+ + 5e- Mn2+ + 4H2O(l)
khi aMnO4- = aMn2+ = 1 :
f. Ag | AgCl (r) |Cl- (dd)
g. Hg (l) | Hg2SO4 (r) |SO42- (dd). Vit pt theo o
h. Pb | PbCO3 (r), CaCO3 (r) |Ca2+ (dd). Vit pt theo o
i. 3Ag+ + Cr 3Ag + Cr3+
j. Pt|H2 (k, 1 atm) | HCl (dd) | AgCl (r) |Ag
k. Pin nng : M|M+ (a1) M+
(a2)|M
5-Mar-15 TS. MTHH 28
Mn+/M
Mn+/M
-
05/03/2015
15
11. Pt|H2 (k, 1 atm) | HCl (a = 0,15) | Hg2Cl2 (r) |Hg. Tm E cho 25oC
oHg2Cl2/Hg = 0,2681
12. H s hot trung bnh ca HBr trong dd nc long 25oC l 0,930 (
5,0 mmolkg-1) v 0,879 ( 20,0 mmolkg-1). Xt c Hydrogen trong dd HBr
25oC hot ng vi p sut 1,15 atm. Tm s thay i ca th c khi nng
axit thay i t 5,0 mmolkg-1 sang 20,0 mmolkg-1 . Chp nhn h s hot
ion m v ion dng bng nhau. (S : 34,2 mV)
5-Mar-15 TS. MTHH 29
Lin h sc in ng nhit
G = H - TS
5-Mar-15 TS. MTHH 30
G
T = - S p
(-nFE)
T = - S p
E
T S =
p nF
E
T p : h s nhit ca s
Bin thin entropi S ca p :
-nFE = H E
T p - TnF
E = E
T p + T
H
nF -
-
05/03/2015
16
13. Cho pin Pt|H2 (k) |HBr (dd) | AgBr (r)|Ag v
s Eo (V) = 0,07131 4,99.10-4(T 298) 3,45.10-6(T-298)2
Tm NL Gibbs, entanpi, entropi tiu chun ca p 298 K.
5-Mar-15 TS. MTHH 31
ng dng - Hng s cn bng ca p
Khi h pin ttcb :
G = 0 : E = 0, Q = K = hng s CB
5-Mar-15 TS. MTHH 32
Eopin = RT
nF lnK
= 0,059
n logK Eopin
298K :
K = 10 nEo/0,059
14. Tnh hng s CB ca p trong pin Cu-Zn : Zn|Zn2+Cu2+|Cu
-
05/03/2015
17
15. Tm hng s cn bng 298,15K ca 2Cu+ (aq) Cu(r) + Cu2+
16. Tm tch s tan v tan ca AgCl t cc gi tr th in cc 298,15K :
5-Mar-15 TS. MTHH 33
Ag+(aq) + e Ag(s) +0.80
AgCl(s) + e Ag(s) + Cl- +0.22
ng dng - o pH ca dung dch
Nguyn tc :
o s ca pin gm :
c so snh : c Hidro, c Calomen, c Bc clorua
c ch th : c th ph thuc vo pH ca dd cn o, nh c Hidro, c
Quinidron, c thy tinh
1. c Hydro l c ch th :
Pt|H2 (1atm) |H+ (?) KClbh|Hg2Cl2 |Hg
c Hydro : H+/H2 = 0,059lgaH+ = -0,059pH
c Calomen c th x bng thc nghim l : Hg2Cl2/Hg = 0,2438 V
S ca pin : E = Hg2Cl2/Hg - H+/H2 = 0,2438 + 0,059pH
pH =
5-Mar-15 TS. MTHH 34
-
05/03/2015
18
ng dng - o pH ca dung dch
2. in cc Quinidron l c ch th :
in cc Quinidron : Pt|Q(dd), QH2(dd), H+(dd)
Quinidron tan t trong nc, p phn ly :
Quinidron (C6H4)2O2(OH)2 Quinon (Q) C6H4O2 + Hydroquinon (QH2) C6H4(OH)2
Cp oxi ha/kh : Q/QH2
Q + 2H+ + 2e QH2
Mch o pH : Hg|Hg2Cl2 KClbhH+(?), Q(dd), QH2(dd)| Pt
E = o quinidron 0,059 pH - cal
5-Mar-15 TS. MTHH 35
Q/QH2 = o
RT
2F ln
aQH2
aQ.aH+2
aQH2 aQ = const
= o + 0,059lgaH+ = o
0,059 pH
ng dng - o pH ca dung dch
3. c thy tinh l c ch th :
Bu thy tinh : nhy vi ion H+ (lm t liti silicat + oxit KL kim)
Giao din bu thy tinh/dd : s trao i ca H+ qua mng thy tinh
bc nhy th :
H+(dung dch) H+ (thy tinh)
(Si-O- + H+ Si-O-H+)
Pha trong bu tt : dd HCl 0,1 M (aH+ = const) : hiu th mng pha trong = const
Bn ngoi bu tt : dd cn o pH c aH+
Th c = hiu s 2 bc nhy th 2 pha ca mng tt
TT = o
TT + 0,059lgaH+
Mch o pH : Ag|AgCl|HCl 0,1 N|thy tinh|dd cn o pHcalomen
5-Mar-15 TS. MTHH 36
-
05/03/2015
19
17. Thit lp pin to ra cc p sau, tm sut in ng tiu chun tng ng :
a. Ag+ + Cl- AgCl
b. 2H2(k) + O2(k) 2H2O(l)
c. 2Na(r) + 2H2O(l) 2NaOH(dd) + H2(k)
d. H2(k) + I2(r)2 HI(dd)
e. H3O+ (dd) + OH-(dd) 2H2O(l)
18. Tm p in cc, p pin v sc in ng tiu chun ca pin sau :
a. Pt K3[Fe(CN)6](dd) K4[Fe(CN)6](dd) CrCl3(dd) Cr
b. Pt Cl2(k) HCl(dd) K2CrO4(dd) Ag2CrO4(r) Ag
c. Cu Cu2+(dd) Mn2+(dd), H+(dd) MnO2(r) Pt
d. Pt H2(k) HCl(dd) AgCl(r) Ag
e. Bi Bi2S3(r) Bi2S3(dd) Bi
f. Zn(r) ZnCl2(dd) Hg2Cl2(r) Hg(l)
19. Tm th c chun ca Fe3+/Fe t th in cc chun ca 2 cp Fe3+/Fe2+ v Fe2+/Fe. (S : -0,037V)
20. Tm sc in ng 25oC ca cc pin nng :
a. Ag AgNO3 (0,01m) AgNO3 (0,1m) Ag
b. Ag AgCl NaCl (0,1m) NaCl (0,01m) AgCl Ag
Bit h s hot trung bnh ca dd AgNO3 0,01m v 0,1m l 0,897 v 0,734. Chp nhn h s
hot ca ion dng v m bng nhau.
TS. MTHH 37
21. 25oC pin Cd-Hg CdCl2 0,01m AgCl Ag c sc in ng 0,7585 V. Cho Eo = 0,5732V. Tm CdCl2
trong dd CdCl2 0,01m. So snh kt qu thu c khi tnh ton theo l thuyt Debye-Huckel.
22. Cho : Ag+ + e Ag o = 0,7996V
[Ag(NH3)2]+ + e Ag + 2NH3
o = 0,373V
Tm hng s khng bn ca phc [Ag(NH3)2]+
23. Xt pin Pt H2(k, p) HCl(dd) AgCl(r) Ag. 25oC v nng HCl 0,01m, sc in ng ca pin l
0,4658 V.
a. Vit pt Nernst cho p pin.
b. Tm G ca p
c. Gi s nh lut Debye-Huckel p dng c, tm oAgCl/Ag khi p = 1atm
24. 25oC sc in ng tiu chun ca pin Bi Bi2S3 (r) Bi2S3 (dd) Bi l 0,96V. Tm tch s tan v tan
ca Bi2S3.
25. 25oC v CuSO4 1,0.10-3 m, ZnSO4 3,0.10
-3 m. P Cu-Zn c Go=-212,7 kJ/mol. Tm :
a. Lc ion ca mi dd.
b. H s hot trung bnh ca mi dd in ly
c. Sc tiu chun ca pin
d. Sc ca pin
Cho + = -=
26. Cho pin Ag|AgCl (r) |HCl (dd) | Hg2Cl2 (r)|Hg 25
oC c sd l 0,0465V, h s nhit ca s l
3,39.10-4 V/. Tm lng nhit do pin ta ra hay thu vo.
5-Mar-15 TS. MTHH 38
-
05/03/2015
20
27. Tm tch s tan v tan ca Hg2Cl2 t cc gi tr th in cc 298,15K :
Hg2Cl2 +2e2Hg+2Cl- 0,27V
Hg22+ + 2e 2Hg 0,79V
Cho p ha tan : Hg2Cl2 (r) Hg22+(dd) + 2Cl- (dd)
28. Ch c th y Ag ra khi lng vt dung dch Ag+ trong qung ch.
Pb(r) + 2Ag+(dd) Pb2+(dd) + 2Ag(r)
Tm hng s cn bng K v G
298 K ca p ny.
Tm sut in ng ca pin nu bt u vi Ag+ 0,02 M v Pb2+ 0,02 M.
Cho oPb = -0,13V v o
Ag = 0,8V. Chp nhn dng nng thay cho hot .
5-Mar-15 TS. MTHH 39
Hng dn gii BT 17.
a. Ag+ + Cl- AgCl
b. Pt H2(k) H+(dd), H2O(l) O2(k) Pt E
o = +1,23V
H2 - 2e 2H+
4H+ + O2 + 4e 2H2O o = +1,23V
c. Na(r) NaOH(dd) H2(k) Pt Eo = +1,88V
d. Pt H2(k) HI (dd) I2(r) Pt
e. Pt H2(k) H2O(l) H2(k) Pt Eo = +0,83V
2H3O+ + 2e H2 + 2H2O 0,00V
H2 + 2OH- -2e2H2O +0,83V
18.
a. Eo = -1,1V
b. Eo = -1,36 + 0,45 = -0,91V
c. Eo = +0,89V
d. Eo = +0,22 V; 2AgCl(r)+H2(k)2HCl(dd) + 2Ag(r)
20.
a. E=0,059 lg aAg+(0,1m) / aAg+(0,01m) = 0,054V
= +
b. E= 0,055V
21.
E=Eo 0,059.3/2 lga
= 0,5076
Theo D-H : = 0,666
5-Mar-15 TS. MTHH 40
-
05/03/2015
21
22.
[Ag(NH3)2]+ Ag+ + 2NH3 K
Ag - e Ag+ o = -0,7996V
[Ag(NH3)2]+ + e Ag + 2NH3
o = 0,373V
Eo= 0,373-0,7996
K=10Eo/0,059 = 6.10-8
23.
a. E=Eo 2RT/F lg(.m/pH21/2)
c. lg = -0,509m1/2 =-0,0509 o = 0,223
24.
2,4.10-98; 1,2.10-20
25.
a. 4.10-3 & 1,2.10-2
b. 0,74 & 0,6
c. 1,102V
d. 1,08
26.
5,26 kJ/mol
27.
2,36.10-18; 8,38.10-7
TS. MTHH 41
top related